Login
Register
E-alert
2025 Vol. 55, No. 5
Display Method:
2025, 55(5): 1-9.
doi: 10.3724/j.gyjzG24060604
Abstract:
In hot-summer and cold-winter regions， high-rise office buildings exhibit high energy consumption intensity， and the design of photovoltaic facades holds significant energy-saving potential. However， many design parameters pose complexity in their impact on building energy consumption and power generation. Therefore， based on surveys of 43 high-rise office buildings in hot-summer and cold-winter regions （using Wuhan as an example）， typical models of high-rise office building facades were established using ArchiCad software. Coupled with EcoDesigner and PVsyst software， energy consumption and power generation simulations were conducted to explore the influence of building morphology （orientation， standard floor area， floor height， planar aspect ratio）， window-to-wall ratio， and three types of photovoltaic facade forms （vertical surface protrusion， triangular protrusion， and sunshade） on building energy consumption and power generation. The results indicated that： 1） among the three types of design parameters considered in this study， the photovoltaic facade forms had the most significant impact on comprehensive energy consumption， with an energy-saving rate ranging from 23.86% to -2.15%， while building form design parameters had the least significant effect on comprehensive energy consumption， with variations of only 1.4% to -0.89%.； 2） in the design of photovoltaic facades， more attention should be paid to increasing the area of the photovoltaic facade rather than enhancing the intensity of annual solar irradiation； 3） on the premise of identical photovoltaic facade forms and satisfied ventilation/daylighting requirements， the energy-saving effect increased as the window-to-wall ratio decreased.
In hot-summer and cold-winter regions， high-rise office buildings exhibit high energy consumption intensity， and the design of photovoltaic facades holds significant energy-saving potential. However， many design parameters pose complexity in their impact on building energy consumption and power generation. Therefore， based on surveys of 43 high-rise office buildings in hot-summer and cold-winter regions （using Wuhan as an example）， typical models of high-rise office building facades were established using ArchiCad software. Coupled with EcoDesigner and PVsyst software， energy consumption and power generation simulations were conducted to explore the influence of building morphology （orientation， standard floor area， floor height， planar aspect ratio）， window-to-wall ratio， and three types of photovoltaic facade forms （vertical surface protrusion， triangular protrusion， and sunshade） on building energy consumption and power generation. The results indicated that： 1） among the three types of design parameters considered in this study， the photovoltaic facade forms had the most significant impact on comprehensive energy consumption， with an energy-saving rate ranging from 23.86% to -2.15%， while building form design parameters had the least significant effect on comprehensive energy consumption， with variations of only 1.4% to -0.89%.； 2） in the design of photovoltaic facades， more attention should be paid to increasing the area of the photovoltaic facade rather than enhancing the intensity of annual solar irradiation； 3） on the premise of identical photovoltaic facade forms and satisfied ventilation/daylighting requirements， the energy-saving effect increased as the window-to-wall ratio decreased.
The Fun of Interactive： Visiting Corridor Design from the Perspective of Industrial Cultural Tourism
2025, 55(5): 10-16.
doi: 10.3724/j.gyjzG23080709
Abstract:
In the context of high-quality development of various industries， the study of "the fun of interactive" of visiting corridors from the perspective of industrial tourism is not only an effective response to the high-quality development of industrial buildings in the new era， but also an objective expression of the "open and sharing" development concept. Visiting corridors are an excellent channel for modern factories to display corporate culture， and they also serve as a buffer channel for people flow and logistics， making the production clean area free from external influences. From the perspective of industrial cultural tourism， this paper systematically examined the types， functional layouts， spatial scales， and interface forms of visiting corridors， and summarized the design principles of the general applicability of visiting corridors， aiming to improve their expression in terms of interest， interaction， openness， and humanity．
In the context of high-quality development of various industries， the study of "the fun of interactive" of visiting corridors from the perspective of industrial tourism is not only an effective response to the high-quality development of industrial buildings in the new era， but also an objective expression of the "open and sharing" development concept. Visiting corridors are an excellent channel for modern factories to display corporate culture， and they also serve as a buffer channel for people flow and logistics， making the production clean area free from external influences. From the perspective of industrial cultural tourism， this paper systematically examined the types， functional layouts， spatial scales， and interface forms of visiting corridors， and summarized the design principles of the general applicability of visiting corridors， aiming to improve their expression in terms of interest， interaction， openness， and humanity．
2025, 55(5): 17-26.
doi: 10.3724/j.gyjzG23082410
Abstract:
With the rapid development of global urbanization， the ecological environment has been damaged， and the climate has become more and more severe. The most obvious manifestation of this is the urban local microclimate， where perceptions of hot and cold microclimates seriously interfere with people's daily life and work. The urban local microclimate is formed by the interaction of multiple spatial elements， among which building combination and form are the main factors affecting the local spatial wind and thermal environment. As a gateway to the city and a climate-sensitive area， the microclimate environment directly affects the city’s image as well as people’s work and travel. Therefore， this study took Chengdu， a hot-summer and cold-winter region， as an example， through the simulation and superposition analysis of the wind-heat environment in the open space in front of the stationin with different building envelopes during summer and winter， it was found that the envelopes had a more significant effect on the wind-heat effect and uncomfortable values in winter， showing a negative correlation； in summer， the "mouth"-shaped differed from the "paralle"- shaped， and the "paralle"-shaped differed from it in winter， which was negatively correlated. In summer， the wind-heat environment in open spaces with either "mouth"-shaped or "parallel"-shaped configurations showed greater sensitivity to enclosure ratios， while in winter， similar sensitivity was observed between "mouth"-shaped and U-shaped configurations.
With the rapid development of global urbanization， the ecological environment has been damaged， and the climate has become more and more severe. The most obvious manifestation of this is the urban local microclimate， where perceptions of hot and cold microclimates seriously interfere with people's daily life and work. The urban local microclimate is formed by the interaction of multiple spatial elements， among which building combination and form are the main factors affecting the local spatial wind and thermal environment. As a gateway to the city and a climate-sensitive area， the microclimate environment directly affects the city’s image as well as people’s work and travel. Therefore， this study took Chengdu， a hot-summer and cold-winter region， as an example， through the simulation and superposition analysis of the wind-heat environment in the open space in front of the stationin with different building envelopes during summer and winter， it was found that the envelopes had a more significant effect on the wind-heat effect and uncomfortable values in winter， showing a negative correlation； in summer， the "mouth"-shaped differed from the "paralle"- shaped， and the "paralle"-shaped differed from it in winter， which was negatively correlated. In summer， the wind-heat environment in open spaces with either "mouth"-shaped or "parallel"-shaped configurations showed greater sensitivity to enclosure ratios， while in winter， similar sensitivity was observed between "mouth"-shaped and U-shaped configurations.
2025, 55(5): 27-36.
doi: 10.3724/j.gyjzG24041501
Abstract:
Modern sports architecture bears witness to the development and evolution of architecture， cities， and society， serving as an important carrier of historical， artistic， scientific， and social values. However， the current research on the value of modern sports architecture heritage in China remains insufficient， lacking comprehensive evaluation criteria， weights， and appropriate methodologies. This paper conducted an in-depth analysis of modern sports architecture in China， proposed the indicators and weights for the evaluation system of the value of modern architecture heritage in China， and presented a suitable fuzzy comprehensive evaluation method for assessing the value of modern and contemporary sports architecture heritage in China. Furthermore， the evaluation and application of representative modern sports architecture heritage in China were conducted. The research demonstrated that the evaluation system proposed in this paper， based on fuzzy comprehensive evaluation， possessed good feasibility and guidance， providing a more scientific approach for conservation and renovation decision-making processes.
Modern sports architecture bears witness to the development and evolution of architecture， cities， and society， serving as an important carrier of historical， artistic， scientific， and social values. However， the current research on the value of modern sports architecture heritage in China remains insufficient， lacking comprehensive evaluation criteria， weights， and appropriate methodologies. This paper conducted an in-depth analysis of modern sports architecture in China， proposed the indicators and weights for the evaluation system of the value of modern architecture heritage in China， and presented a suitable fuzzy comprehensive evaluation method for assessing the value of modern and contemporary sports architecture heritage in China. Furthermore， the evaluation and application of representative modern sports architecture heritage in China were conducted. The research demonstrated that the evaluation system proposed in this paper， based on fuzzy comprehensive evaluation， possessed good feasibility and guidance， providing a more scientific approach for conservation and renovation decision-making processes.
2025, 55(5): 37-45.
doi: 10.3724/j.gyjzG25012802
Abstract:
Due to inadequate conservation frameworks， substantial industrial heritage in China has been demolished or damaged， necessitating digital reconstruction to preserve historical information. An approach is proposed for 3D data restoration of demolished industrial heritage with incomplete UAV photogrammetry datasets. Depth image technology refines aerial imagery through depth-aware analysis to optimize point clouds， enhancing completeness in information-deficient scenarios. By integrating historical records， remote sensing， and archival photos， detailed point cloud refinement and scene reconstruction are achieved. The resulting 3D models enable morphological restoration of urban industrial architecture， providing a systematic framework for digital heritage preservation and database development using depth-image-based data recovery techniques.
Due to inadequate conservation frameworks， substantial industrial heritage in China has been demolished or damaged， necessitating digital reconstruction to preserve historical information. An approach is proposed for 3D data restoration of demolished industrial heritage with incomplete UAV photogrammetry datasets. Depth image technology refines aerial imagery through depth-aware analysis to optimize point clouds， enhancing completeness in information-deficient scenarios. By integrating historical records， remote sensing， and archival photos， detailed point cloud refinement and scene reconstruction are achieved. The resulting 3D models enable morphological restoration of urban industrial architecture， providing a systematic framework for digital heritage preservation and database development using depth-image-based data recovery techniques.
2025, 55(5): 46-57.
doi: 10.3724/j.gyjzG24111306
Abstract:
Yunnan-Vietnam Railway， as an important witness of China’s modern traffic development history， has become a typical case of integration of industrial heritage and traditional villages due to its unique characteristics of "station-village symbiosis". Taking the settlement of Bise Village Station on the Yunnan-Vietnam Railway as the research object， this paper puts forward the strategy of scientific protection and sustainable development by constructing an index system that integrates the value evaluation of heritage and the evaluation of traditional villages. In this paper， AHP （analytic hierarchy process） combined with all-permutation polygon graphic index method and the five-dimensional value framework of history， art， science， society， and culture specified in the Principles for the Conservation of Heritage Sites in China， are used to systematically evaluate Bise Village. The results show that the core value of Bise Village is embodied in the scientific value of the "double-station and double-track" technical node and the social and cultural value of multicultural blending. The mixed structure of stone houses embodies the adaptability wisdom to the mountainous environment. The multi-aesthetic contrast formed between French red tile buildings and Chinese gray brick quadrangle courtyard， and the cultural integrity of the non-material relics， such as the red memory of National Protection Movement， caravan culture， and so on. However， the core value （science and culture） of Bise Village has not been fully displayed， and a core-peripheral development imbalance problem still exists. In the future， it is necessary to further explore the cooperative mechanism of heritage protection and rural revitalization to realize the sustainable development path of "Technical Restoration-Cultural Activation-Regional Linkage".
Yunnan-Vietnam Railway， as an important witness of China’s modern traffic development history， has become a typical case of integration of industrial heritage and traditional villages due to its unique characteristics of "station-village symbiosis". Taking the settlement of Bise Village Station on the Yunnan-Vietnam Railway as the research object， this paper puts forward the strategy of scientific protection and sustainable development by constructing an index system that integrates the value evaluation of heritage and the evaluation of traditional villages. In this paper， AHP （analytic hierarchy process） combined with all-permutation polygon graphic index method and the five-dimensional value framework of history， art， science， society， and culture specified in the Principles for the Conservation of Heritage Sites in China， are used to systematically evaluate Bise Village. The results show that the core value of Bise Village is embodied in the scientific value of the "double-station and double-track" technical node and the social and cultural value of multicultural blending. The mixed structure of stone houses embodies the adaptability wisdom to the mountainous environment. The multi-aesthetic contrast formed between French red tile buildings and Chinese gray brick quadrangle courtyard， and the cultural integrity of the non-material relics， such as the red memory of National Protection Movement， caravan culture， and so on. However， the core value （science and culture） of Bise Village has not been fully displayed， and a core-peripheral development imbalance problem still exists. In the future， it is necessary to further explore the cooperative mechanism of heritage protection and rural revitalization to realize the sustainable development path of "Technical Restoration-Cultural Activation-Regional Linkage".
2025, 55(5): 58-67.
doi: 10.3724/j.gyjzG24072209
Abstract:
To investigate the shear-bearing capacity of high-strength bolt efficient connections with high slip-resistant coefficients under elevated temperatures， tensile tests were first conducted on Q355 and Q960 base material specimens （matching the connection components） and Grade 8.8 bolt material specimens under both ambient and high-temperature conditions. This established the temperature-dependent relationships for elastic modulus， yield strength， and tensile strength of the materials. Subsequently， high-temperature shear performance tests were performed on eight high-strength bolt efficient connections to examine the effects of different temperatures and hole configurations on failure modes， slip loads， and ultimate loads. The results demonstrate that： the failure mode of high-strength bolt efficient connections transitions from net-section failure to bolt shear failure within the 300-400℃ temperature range； both slip load and ultimate load decrease with increasing temperature， showing 75% and 51% reductions respectively at 500℃ compared to ambient conditions for standard hole specimens； different hole configurations exhibit limited influence on the ultimate shear capacity of connections at 500 ℃.
To investigate the shear-bearing capacity of high-strength bolt efficient connections with high slip-resistant coefficients under elevated temperatures， tensile tests were first conducted on Q355 and Q960 base material specimens （matching the connection components） and Grade 8.8 bolt material specimens under both ambient and high-temperature conditions. This established the temperature-dependent relationships for elastic modulus， yield strength， and tensile strength of the materials. Subsequently， high-temperature shear performance tests were performed on eight high-strength bolt efficient connections to examine the effects of different temperatures and hole configurations on failure modes， slip loads， and ultimate loads. The results demonstrate that： the failure mode of high-strength bolt efficient connections transitions from net-section failure to bolt shear failure within the 300-400℃ temperature range； both slip load and ultimate load decrease with increasing temperature， showing 75% and 51% reductions respectively at 500℃ compared to ambient conditions for standard hole specimens； different hole configurations exhibit limited influence on the ultimate shear capacity of connections at 500 ℃.
2025, 55(5): 68-75.
doi: 10.3724/j.gyjzG22110311
Abstract:
In view of the problem that the modular columns of existing modular building steel structures cannot effectively cooperate with each other， this paper proposed the concept and technology to realize the self-locking effective connection and cooperative work between adjacent modular columns without damaging the enclosure structure of the module unit. A numerical simulation method was used to study the bearing performance of the novel cooperative load-bearing modular columns and the influence of key parameters. The results showed that the cooperative load-bearing module column exhibited good bearing capacity， high ultimate bearing capacity， and strong deformation capacity. Compared with the existing module column， the ultimate bearing capacity of the cooperative load-bearing module column was greatly improved， and the cooperative work effect between the columns was obvious. The bearing capacity of the column group increased greatly when lateral connections between columns were formed from nothing， but when lateral connections between modular columns were formed， the effect of increasing the number of lateral connection between columns on improving the bearing capacity of components was relatively weakened. With the increase in slenderness ratio， the lateral connections between columns played an obvious role， and the degree of coordination between columns increased. With the increase of the number of lock components， the ultimate bearing capacity of the cooperative load-bearing module column increasesd slightly. When the number of lock components increased to 3， further increases in the number of lock components did not significantly improve the ultimate bearing capacity of columns.
In view of the problem that the modular columns of existing modular building steel structures cannot effectively cooperate with each other， this paper proposed the concept and technology to realize the self-locking effective connection and cooperative work between adjacent modular columns without damaging the enclosure structure of the module unit. A numerical simulation method was used to study the bearing performance of the novel cooperative load-bearing modular columns and the influence of key parameters. The results showed that the cooperative load-bearing module column exhibited good bearing capacity， high ultimate bearing capacity， and strong deformation capacity. Compared with the existing module column， the ultimate bearing capacity of the cooperative load-bearing module column was greatly improved， and the cooperative work effect between the columns was obvious. The bearing capacity of the column group increased greatly when lateral connections between columns were formed from nothing， but when lateral connections between modular columns were formed， the effect of increasing the number of lateral connection between columns on improving the bearing capacity of components was relatively weakened. With the increase in slenderness ratio， the lateral connections between columns played an obvious role， and the degree of coordination between columns increased. With the increase of the number of lock components， the ultimate bearing capacity of the cooperative load-bearing module column increasesd slightly. When the number of lock components increased to 3， further increases in the number of lock components did not significantly improve the ultimate bearing capacity of columns.
2025, 55(5): 76-85.
doi: 10.3724/j.gyjzG22102904
Abstract:
In order to solve the problem that traditional buckling-restrained braces do not dissipate energy under minor earthquakes， a novel double-yield buckling-restrained brace （DYBRB） with two-stage energy dissipation capability has been proposed. The brace yields energy dissipation and provides stiffness for the structure under minor earthquakes， while demonstrating better energy dissipation capacity under moderate to strong earthquakes. By analyzing the structural characteristics of the DYBRB， the working mechanism of this brace was obtained， the theoretical formulas for the double-yield displacement ratio and the yield bearing capacity ratio of the brace were deduced， and the main parameters affecting its design were identified.The DYBRB numerical model was established by ABAQUS， and its seismic performance was verified from three aspects： energy dissipation capacity， bearing capacity unbalance characteristics， and plastic deformation capacity. The research results showed that the DYBRB's hysteresis curve was stable，full， and symmetrical in tension and compression.The DYBRB exhibited good double-yield energy dissipation characteristics and plastic deformation capacity， enabling multi-level energy dissipation under different levels of earthquake action.
In order to solve the problem that traditional buckling-restrained braces do not dissipate energy under minor earthquakes， a novel double-yield buckling-restrained brace （DYBRB） with two-stage energy dissipation capability has been proposed. The brace yields energy dissipation and provides stiffness for the structure under minor earthquakes， while demonstrating better energy dissipation capacity under moderate to strong earthquakes. By analyzing the structural characteristics of the DYBRB， the working mechanism of this brace was obtained， the theoretical formulas for the double-yield displacement ratio and the yield bearing capacity ratio of the brace were deduced， and the main parameters affecting its design were identified.The DYBRB numerical model was established by ABAQUS， and its seismic performance was verified from three aspects： energy dissipation capacity， bearing capacity unbalance characteristics， and plastic deformation capacity. The research results showed that the DYBRB's hysteresis curve was stable，full， and symmetrical in tension and compression.The DYBRB exhibited good double-yield energy dissipation characteristics and plastic deformation capacity， enabling multi-level energy dissipation under different levels of earthquake action.
2025, 55(5): 86-94.
doi: 10.3724/j.gyjzG23072602
Abstract:
In order to promote the widespread application of modular steel structures in practical engineering and solve the comprehensive problems of weak connection performance of connectors， difficulty in bolt installation， and difficulty in ensuring welding quality during beam-column welding in the existing forms of joint connections between modular units， this paper proposes a type of joint design for steel modular units using single-sided bolts and inner sleeves. This joint mainly consists of inner sleeves， high-strength single-sided bolts， square steel pipe columns， H-shaped steel beams， etc. By using ANSYS finite element simulation software to perform quasi-static and low-frequency reciprocating loading on the four established connection modes of joints， the failure modes， bending moment capacity， hysteresis curve， skeleton curve， and energy dissipation performance of the four nodes were analyzed. Finally， referring to existing structural engineering， the mechanical performance parameters of the joints obtained from the research were assigned to the overall multi-layer steel structure model established by MIDAS/Gen， and the structure was subjected to dead loads， live loads， wind loads， and seismic actions to further explore the connection performance of joints within the overall structure. The results showed that when a single-sided extended end-plate was used in the floor beam， the bending capacity of the joint increased by approximately 8.32%. When intermediate connecting bolts and cover plates were used， the bending capacity of the joint increased by approximately 16.61% and 10.33%， respectively. When the flush end plates were used， the hysteresis curves of the joint significantly exhibited pinching phenomenon， significantly reducing energy dissipation performance. The connection performance of this joint not only met the requirements of existing specification（GB/T 50011-2010） but also exhibited good energy dissipation performance， meeting the requirements of multi-layer pure modular steel structures up to 8 stories.
In order to promote the widespread application of modular steel structures in practical engineering and solve the comprehensive problems of weak connection performance of connectors， difficulty in bolt installation， and difficulty in ensuring welding quality during beam-column welding in the existing forms of joint connections between modular units， this paper proposes a type of joint design for steel modular units using single-sided bolts and inner sleeves. This joint mainly consists of inner sleeves， high-strength single-sided bolts， square steel pipe columns， H-shaped steel beams， etc. By using ANSYS finite element simulation software to perform quasi-static and low-frequency reciprocating loading on the four established connection modes of joints， the failure modes， bending moment capacity， hysteresis curve， skeleton curve， and energy dissipation performance of the four nodes were analyzed. Finally， referring to existing structural engineering， the mechanical performance parameters of the joints obtained from the research were assigned to the overall multi-layer steel structure model established by MIDAS/Gen， and the structure was subjected to dead loads， live loads， wind loads， and seismic actions to further explore the connection performance of joints within the overall structure. The results showed that when a single-sided extended end-plate was used in the floor beam， the bending capacity of the joint increased by approximately 8.32%. When intermediate connecting bolts and cover plates were used， the bending capacity of the joint increased by approximately 16.61% and 10.33%， respectively. When the flush end plates were used， the hysteresis curves of the joint significantly exhibited pinching phenomenon， significantly reducing energy dissipation performance. The connection performance of this joint not only met the requirements of existing specification（GB/T 50011-2010） but also exhibited good energy dissipation performance， meeting the requirements of multi-layer pure modular steel structures up to 8 stories.
2025, 55(5): 95-103.
doi: 10.3724/j.gyjzG23021107
Abstract:
Static load tests were carried out on three types of lightweight composite slab units with different inner packing structures. The composite slab unit consists of a thin-walled steel framework filled with steel rebars/wire mesh reinforced ceramsite concrete. These units can be assembled to form a new type of lightweight prefabricated floor slab. The test results showed that the composite slab unit exhibitsed significant bearing capacity and deformation capacity. When specimens exhibited through cracking at the concrete bottom， severe buckling of thin-walled steel members， and crushing of the support-end concrete， with the vertical displacement of specimens reaching L/45 （L = span length）， the concrete filled in the thin-walled steel framework was not pushed out by the concentrated load acting on the center of the grid； the bearing capacity of the composite slab unit was improved by properly arranging the steel rebars and laying the steel wire mesh in the area grid； increasing the reinforcement ratio in the area of the composite slab unit not only improved the overall elastic stiffness but also enhanced the deformation capacity of the specimens； the increase of the ultimate load of the composite slab unit was greater than the increase of the elastic stiffness when the steel wire mesh was arranged in the framework area of the specimens.
Static load tests were carried out on three types of lightweight composite slab units with different inner packing structures. The composite slab unit consists of a thin-walled steel framework filled with steel rebars/wire mesh reinforced ceramsite concrete. These units can be assembled to form a new type of lightweight prefabricated floor slab. The test results showed that the composite slab unit exhibitsed significant bearing capacity and deformation capacity. When specimens exhibited through cracking at the concrete bottom， severe buckling of thin-walled steel members， and crushing of the support-end concrete， with the vertical displacement of specimens reaching L/45 （L = span length）， the concrete filled in the thin-walled steel framework was not pushed out by the concentrated load acting on the center of the grid； the bearing capacity of the composite slab unit was improved by properly arranging the steel rebars and laying the steel wire mesh in the area grid； increasing the reinforcement ratio in the area of the composite slab unit not only improved the overall elastic stiffness but also enhanced the deformation capacity of the specimens； the increase of the ultimate load of the composite slab unit was greater than the increase of the elastic stiffness when the steel wire mesh was arranged in the framework area of the specimens.
2025, 55(5): 104-112.
doi: 10.3724/j.gyjzG22101811
Abstract:
In order to explore the influence of the degree of plug wedge tightness on the torsional stiffness of disc-button steel tubular scaffolding， the mechanical properties of the steel tubular scaffolding joint were reasonably analyzed. By constructing the specimens of φ48 and φ60 connection joints of disc fastener frame， the torsional stiffness tests of the joints under different wedge tightness conditions were carried out， and the influence mechanism of plug wedge tightness on the torsional stiffness of the disc-button joint was revealed. Through quantitative analysis of the semi-rigidity of the joint， a reasonable range for plug wedge tightness was proposed. Through statistical nonlinear regression analysis， the relations between initial torsional stiffness and plug wedge tightness in disc-button joints were obtained. The analysis results showed that ： the plug wedge tightness had a great influence on the torsional stiffness of the disc-button joint. The plug wedge tightness should be controlled within a reasonable range to meet the bearing capacity requirements， and by using the "semi-rigid-relaxation-slip" trilinear piecewise broken line model， the torsional line stiffness of disc-button joints at different stages within different wedge tightness ranges was obtained， so as to systematically characterize the mechanical properties of disc-button steel tubular scaffolding and avoid security risks that caused by structural defects.
In order to explore the influence of the degree of plug wedge tightness on the torsional stiffness of disc-button steel tubular scaffolding， the mechanical properties of the steel tubular scaffolding joint were reasonably analyzed. By constructing the specimens of φ48 and φ60 connection joints of disc fastener frame， the torsional stiffness tests of the joints under different wedge tightness conditions were carried out， and the influence mechanism of plug wedge tightness on the torsional stiffness of the disc-button joint was revealed. Through quantitative analysis of the semi-rigidity of the joint， a reasonable range for plug wedge tightness was proposed. Through statistical nonlinear regression analysis， the relations between initial torsional stiffness and plug wedge tightness in disc-button joints were obtained. The analysis results showed that ： the plug wedge tightness had a great influence on the torsional stiffness of the disc-button joint. The plug wedge tightness should be controlled within a reasonable range to meet the bearing capacity requirements， and by using the "semi-rigid-relaxation-slip" trilinear piecewise broken line model， the torsional line stiffness of disc-button joints at different stages within different wedge tightness ranges was obtained， so as to systematically characterize the mechanical properties of disc-button steel tubular scaffolding and avoid security risks that caused by structural defects.
2025, 55(5): 113-122.
doi: 10.3724/j.gyjzG23072806
Abstract:
The effectiveness of the temporary anchorage system is crucial for the safe application of the external steel anchor box cable replacement process. Taking the cable replacement project of a long-span concrete cable-stayed bridge as the background， a cable replacement system that uses pull-bolts as the anchoring system for the external steel anchor box is proposed. A full-scale model and a main beam segment model were designed and manufactured. The working principle and failure mechanism of this cable replacement system were explored through pull-bolt pretension tests and uniaxial static tensile tests under four contact conditions， and validated by numerical simulation. The results indicated that the anchoring performance of the system was determined by the interface friction between the external steel anchor box and the plain concrete pad as well as the bending-shear strength of the pull-bolts. The diagonal pre-tightening process ensured more uniform force distribution among the pull-bolts， and the design should consider the impact of individual bolt failure. The equivalent friction coefficient of dry contact between steel and plain concrete pads was relatively large. Before and after the failure of the plain concrete pad， the pull-bolts transitioned from being primarily in shear to being primarily in bending. Ultra-high performance concrete （UHPC） could be used in this type of cable replacement system.
The effectiveness of the temporary anchorage system is crucial for the safe application of the external steel anchor box cable replacement process. Taking the cable replacement project of a long-span concrete cable-stayed bridge as the background， a cable replacement system that uses pull-bolts as the anchoring system for the external steel anchor box is proposed. A full-scale model and a main beam segment model were designed and manufactured. The working principle and failure mechanism of this cable replacement system were explored through pull-bolt pretension tests and uniaxial static tensile tests under four contact conditions， and validated by numerical simulation. The results indicated that the anchoring performance of the system was determined by the interface friction between the external steel anchor box and the plain concrete pad as well as the bending-shear strength of the pull-bolts. The diagonal pre-tightening process ensured more uniform force distribution among the pull-bolts， and the design should consider the impact of individual bolt failure. The equivalent friction coefficient of dry contact between steel and plain concrete pads was relatively large. Before and after the failure of the plain concrete pad， the pull-bolts transitioned from being primarily in shear to being primarily in bending. Ultra-high performance concrete （UHPC） could be used in this type of cable replacement system.
Study on Size Effect of Bending-Shear Performance of High-Strength Reinforced Concrete Short Columns
2025, 55(5): 123-131.
doi: 10.3724/j.gyjzG24022906
Abstract:
In order to study the size effect of bending-shear performance of high-strength reinforced concrete short columns， based on the principles of geometric similarity and bearing capacity similarity， reinforced concrete short column specimens with cross-sectional side lengths of 300， 500， and 700 mm and concrete strength grade C60 were designed and fabricated. Low cycle repeated quasi-static tests were conducted on the specimens， and the failure modes， skeleton curves， and steel rebar strain of the specimens were discussed. Furthermore， the variation laws of shear performance with cross-sectional size， such as nominal bending stress， nominal rotation angle， P-Δ effect， ductility， energy dissipation capacity， and safety reserve factor， were analyzed. The test results indicated that all specimens had bending-shear failure. Before reaching the peak load， the cracks developed stably， which conformed to Bažant’s Type2 size effect model. The specimen had good ductility and energy dissipation capacity， with a ductility coefficient of 3-5 and a minimum ductility coefficient of 3.65. The nominal bending stress， nominal angle， P-Δ effect， ductility， and energy dissipation capacity exhibited significant size effects. The cross-sectional size increased from 300 mm to 700 mm， the peak nominal stress decreased by 16.7%， the safety reserve coefficient decreased by 11%， the specimen ductility decreased by 36.4%， and the average energy dissipation coefficient decreased by 54.3%. On the basis of tests， the theoretical formula for the bending bearing capacity of normal sections in GB/T 50010—2010 was modified based on the Type2 size effect model. The modified safety reserve coefficient no longer has size effects， ensuring that large-sized specimens have the same safety as small-sized specimens.
In order to study the size effect of bending-shear performance of high-strength reinforced concrete short columns， based on the principles of geometric similarity and bearing capacity similarity， reinforced concrete short column specimens with cross-sectional side lengths of 300， 500， and 700 mm and concrete strength grade C60 were designed and fabricated. Low cycle repeated quasi-static tests were conducted on the specimens， and the failure modes， skeleton curves， and steel rebar strain of the specimens were discussed. Furthermore， the variation laws of shear performance with cross-sectional size， such as nominal bending stress， nominal rotation angle， P-Δ effect， ductility， energy dissipation capacity， and safety reserve factor， were analyzed. The test results indicated that all specimens had bending-shear failure. Before reaching the peak load， the cracks developed stably， which conformed to Bažant’s Type2 size effect model. The specimen had good ductility and energy dissipation capacity， with a ductility coefficient of 3-5 and a minimum ductility coefficient of 3.65. The nominal bending stress， nominal angle， P-Δ effect， ductility， and energy dissipation capacity exhibited significant size effects. The cross-sectional size increased from 300 mm to 700 mm， the peak nominal stress decreased by 16.7%， the safety reserve coefficient decreased by 11%， the specimen ductility decreased by 36.4%， and the average energy dissipation coefficient decreased by 54.3%. On the basis of tests， the theoretical formula for the bending bearing capacity of normal sections in GB/T 50010—2010 was modified based on the Type2 size effect model. The modified safety reserve coefficient no longer has size effects， ensuring that large-sized specimens have the same safety as small-sized specimens.
Analysis of Tensioning Time for Composite Beam-String Structures Considering Solar Radiation Effects
2025, 55(5): 132-142.
doi: 10.3724/j.gyjzG23122503
Abstract:
During the tensioning construction process， the composite beam-string structure is fully exposed to solar radiation. At the moment of structural forming through tensioning， its temperature exceeds ambient levels while demonstrating obvious non-uniformity. In order to clarify the influence of non-uniform temperature effects on the structure’s mechanical properties， a simplified simulation method for non-uniform temperature loads was proposed based on a practical project， and the finite element software ANSYS was used to numerically simulate the structure’s mechanical properties at different tensioning stages under solar exposure. First， field tests and refined numerical simulations were conducted to obtain the temperature distribution patterns along both transverse and longitudinal directions of the top chord composite beam. A temperature gradient model was subsequently established for critical beam sections at various stages. For efficient computation of the beam-string structure considering global non-uniform temperature effects， a quartered beam element simulation method was proposed. Using the finite element software ANSYS， the influence of initial non-uniform temperature fields at different tensioning stages on the structure’s mechanical performance during service life was simulated， and the magnitudes of all mechanical property indicators change in a V shape with the tensioning time. Through a comparison， the optimal tensioning opportunity for the structure was 13：00.
During the tensioning construction process， the composite beam-string structure is fully exposed to solar radiation. At the moment of structural forming through tensioning， its temperature exceeds ambient levels while demonstrating obvious non-uniformity. In order to clarify the influence of non-uniform temperature effects on the structure’s mechanical properties， a simplified simulation method for non-uniform temperature loads was proposed based on a practical project， and the finite element software ANSYS was used to numerically simulate the structure’s mechanical properties at different tensioning stages under solar exposure. First， field tests and refined numerical simulations were conducted to obtain the temperature distribution patterns along both transverse and longitudinal directions of the top chord composite beam. A temperature gradient model was subsequently established for critical beam sections at various stages. For efficient computation of the beam-string structure considering global non-uniform temperature effects， a quartered beam element simulation method was proposed. Using the finite element software ANSYS， the influence of initial non-uniform temperature fields at different tensioning stages on the structure’s mechanical performance during service life was simulated， and the magnitudes of all mechanical property indicators change in a V shape with the tensioning time. Through a comparison， the optimal tensioning opportunity for the structure was 13：00.
2025, 55(5): 143-151.
doi: 10.3724/j.gyjzG22082203
Abstract:
The new type of dry gas holder is a large thin-walled longitudinal-ring cylindrical shell with external reinforcement.The buckling characteristics of this kind of structure are relatively significant and sensitive to dimple imperfections.Due to limitations in test equipment，site conditions，materials，and funds，the buckling characteristics of large thin-walled longitudinal-ring stiffened cylindrical shells with dimple imperfections are generally studied by scaled model test.Generalized similitude condition and scaling laws were derived based on the smear stiffened method and energy method.Based on the dimple imperfection function，using static analysis，dimple imperfections were introduced into ideal stiffened cylindrical shells.An incomplete similarity analysis for the post-buckling of longitudinal-ring rectangular stiffened cylindrical shells with dimple imperfections was carried out under lateral compression.The results showed that combined with the corresponding buckling scaled principle formula， the post-buckling of rectangular stiffened cylindrical shells with dimple imperfections under lateral compression based on the incomplete similarity model could better predict the post-buckling characteristics of the prototype.Furthermore，the closer the Poisson's ratio of the incomplete similarity models was to that of the prototype， the more accurate the post-buckling similarity prediction became.
The new type of dry gas holder is a large thin-walled longitudinal-ring cylindrical shell with external reinforcement.The buckling characteristics of this kind of structure are relatively significant and sensitive to dimple imperfections.Due to limitations in test equipment，site conditions，materials，and funds，the buckling characteristics of large thin-walled longitudinal-ring stiffened cylindrical shells with dimple imperfections are generally studied by scaled model test.Generalized similitude condition and scaling laws were derived based on the smear stiffened method and energy method.Based on the dimple imperfection function，using static analysis，dimple imperfections were introduced into ideal stiffened cylindrical shells.An incomplete similarity analysis for the post-buckling of longitudinal-ring rectangular stiffened cylindrical shells with dimple imperfections was carried out under lateral compression.The results showed that combined with the corresponding buckling scaled principle formula， the post-buckling of rectangular stiffened cylindrical shells with dimple imperfections under lateral compression based on the incomplete similarity model could better predict the post-buckling characteristics of the prototype.Furthermore，the closer the Poisson's ratio of the incomplete similarity models was to that of the prototype， the more accurate the post-buckling similarity prediction became.
2025, 55(5): 152-162.
doi: 10.3724/j.gyjzG22090904
Abstract:
Structures can obtain good self-centering performance by using superelastic NiTi alloy bars. However， due to the mechanical property degradation of NiTi alloy bars， the self-centering and energy dissipation capacity of the structure will be degraded. Therefore， it is necessary to further study the mechanical property stability of NiTi shape memory alloy bars. In this paper， the constant amplitude cyclic tensile tests were carried out on four Ti-50.8%Ni bars after different heat treatments. The effects of the number of cycles and heat treatment conditions on the hysteresis curve morphology， phase transition stress， elastic modulus， residual strain， and energy dissipation capacity of these bars were studied. The degradation of mechanical properties of different bar specimens was compared and analyzed according to the test results. The results showed that the elastic modulus and ultimate stress of NiTi alloy bars changed little in constant amplitude cyclic tensile tests， while the phase transition stress， deformation recovery rate， and equivalent damping ratio degraded significantly. The positive phase transition stress of martensite exhibited a greater reduction compared to the inverse phase transition stress， and the stress degradation of the NiTi alloy bars with better superelasticity was more obvious. Furthermore， both excessively high and low heat treatment temperatures led to superelastic deterioration of NiTi alloy bars， and their energy dissipation capacity was greatly reduced under cyclic loading.
Structures can obtain good self-centering performance by using superelastic NiTi alloy bars. However， due to the mechanical property degradation of NiTi alloy bars， the self-centering and energy dissipation capacity of the structure will be degraded. Therefore， it is necessary to further study the mechanical property stability of NiTi shape memory alloy bars. In this paper， the constant amplitude cyclic tensile tests were carried out on four Ti-50.8%Ni bars after different heat treatments. The effects of the number of cycles and heat treatment conditions on the hysteresis curve morphology， phase transition stress， elastic modulus， residual strain， and energy dissipation capacity of these bars were studied. The degradation of mechanical properties of different bar specimens was compared and analyzed according to the test results. The results showed that the elastic modulus and ultimate stress of NiTi alloy bars changed little in constant amplitude cyclic tensile tests， while the phase transition stress， deformation recovery rate， and equivalent damping ratio degraded significantly. The positive phase transition stress of martensite exhibited a greater reduction compared to the inverse phase transition stress， and the stress degradation of the NiTi alloy bars with better superelasticity was more obvious. Furthermore， both excessively high and low heat treatment temperatures led to superelastic deterioration of NiTi alloy bars， and their energy dissipation capacity was greatly reduced under cyclic loading.
2025, 55(5): 163-171.
doi: 10.3724/j.gyjzG22072114
Abstract:
During the welding process of welded structures composed of steel pipes， typical volumetric welding defects such as porosity are easily formed， which may result in high-cycle fatigue failure of the structure under low-amplitude cyclic loads. Therefore， based on a combination of experimental and numerical simulations， the paper studied the effect of porosity defects on the high-cycle fatigue life of welded steel pipe specimens. First， two groups of steel pipe weldments with intact welding and porosity defects were designed for high-cycle fatigue tests； then a simulation model of porosity weldments was established and verified based on the test results； finally， the influence of different axial directions， circumferential directions， and radial dimensions of porosity defects on the stress concentration factor and high-cycle fatigue life of steel pipe weldments was analyzed using the simulation model. The results showed that the three-dimensional size of porosity defects exhibited different influence mechanisms on the stress concentration and high-cycle fatigue life of steel pipe weldments. Since the size of the welded pipe wall was much smaller than the other two directions， the stress concentration and high-cycle fatigue life were most sensitive to the radial size of the defect， casuing drastic variations in stress concentration and significant reductions in high-cycle fatigue life； because the increase in the axial size of the defect did not reduce the effective bearing area of the section but decreased the specificity of the defect shape， the stress concentration factor decreased with the increase of the axial size of the defect， thereby maintaining a long high-cycle fatigue life； since the increased circumferential size of the defect reduced the effective bearing area of the section， the stress concentration factor increased with the increase of the defect's circumferential size， thereby decreasing the high-cycle fatigue life to a certain extent.
During the welding process of welded structures composed of steel pipes， typical volumetric welding defects such as porosity are easily formed， which may result in high-cycle fatigue failure of the structure under low-amplitude cyclic loads. Therefore， based on a combination of experimental and numerical simulations， the paper studied the effect of porosity defects on the high-cycle fatigue life of welded steel pipe specimens. First， two groups of steel pipe weldments with intact welding and porosity defects were designed for high-cycle fatigue tests； then a simulation model of porosity weldments was established and verified based on the test results； finally， the influence of different axial directions， circumferential directions， and radial dimensions of porosity defects on the stress concentration factor and high-cycle fatigue life of steel pipe weldments was analyzed using the simulation model. The results showed that the three-dimensional size of porosity defects exhibited different influence mechanisms on the stress concentration and high-cycle fatigue life of steel pipe weldments. Since the size of the welded pipe wall was much smaller than the other two directions， the stress concentration and high-cycle fatigue life were most sensitive to the radial size of the defect， casuing drastic variations in stress concentration and significant reductions in high-cycle fatigue life； because the increase in the axial size of the defect did not reduce the effective bearing area of the section but decreased the specificity of the defect shape， the stress concentration factor decreased with the increase of the axial size of the defect， thereby maintaining a long high-cycle fatigue life； since the increased circumferential size of the defect reduced the effective bearing area of the section， the stress concentration factor increased with the increase of the defect's circumferential size， thereby decreasing the high-cycle fatigue life to a certain extent.
2025, 55(5): 172-180.
doi: 10.3724/j.gyjzG25030509
Abstract:
The carbon emission factor of steel is a critical basis for carbon emission accounting in civil and structural engineering. Nevertheless， the existing factors provided by current standards and literature exhibit significant variability and fail to reflect the time-varying characteristic of steel industry evolution. This paper collected production inventory data from 10 representative Chinese iron & steel enterprises using blast furnaces and converters as their main production equipment， along with data provided by the statistical annual reports from the China Iron & Steel Association. Based upon this， a material and energy inventory database was established for structural steel products over the past five years. By using the input-output method， the carbon emission factors for steel products were calculated from these statistical data. Considering the environmental performance data provided by the steel industry Environmental Product Declaration （EPD） platform， the data samples and statistical parameters for the carbon emission factors of steel rebars， section steel， steel plates， and general steel products were established. Based on this analysis， recommended values for the carbon emission factors of commonly-used steel products in civil and structural engineering were proposed. The main conclusions are as follows： 1） The recommended carbon emission factors for steel rebars， section steels， and steel plates are 2150 kg CO2e/t， 2260 kg CO2e/t， and 2240 kg CO2e/t， respectively. 2） The carbon emission factors of steel rebars， section steel， and steel plates calculated herein are 190 kg CO2e/t， 105 kg CO2e/t， and 160 kg CO2e/t lower，respectively， than the corresponding values specified in the Standard for Building Carbon Emission Calculation（GB/T 51366-2019）， demonstrating evident decarbonization of these steel products over the past five years. 3） Compared to the carbon emission factors reported in the 2004 literature， the values calculated in this study show a reduction of more than 1300 kg CO2e/t for steel rebars， section steel， and steel plates， demonstrating the remarkable progress in the green and low-carbon development of structural steel products in China over the past two decades.
The carbon emission factor of steel is a critical basis for carbon emission accounting in civil and structural engineering. Nevertheless， the existing factors provided by current standards and literature exhibit significant variability and fail to reflect the time-varying characteristic of steel industry evolution. This paper collected production inventory data from 10 representative Chinese iron & steel enterprises using blast furnaces and converters as their main production equipment， along with data provided by the statistical annual reports from the China Iron & Steel Association. Based upon this， a material and energy inventory database was established for structural steel products over the past five years. By using the input-output method， the carbon emission factors for steel products were calculated from these statistical data. Considering the environmental performance data provided by the steel industry Environmental Product Declaration （EPD） platform， the data samples and statistical parameters for the carbon emission factors of steel rebars， section steel， steel plates， and general steel products were established. Based on this analysis， recommended values for the carbon emission factors of commonly-used steel products in civil and structural engineering were proposed. The main conclusions are as follows： 1） The recommended carbon emission factors for steel rebars， section steels， and steel plates are 2150 kg CO2e/t， 2260 kg CO2e/t， and 2240 kg CO2e/t， respectively. 2） The carbon emission factors of steel rebars， section steel， and steel plates calculated herein are 190 kg CO2e/t， 105 kg CO2e/t， and 160 kg CO2e/t lower，respectively， than the corresponding values specified in the Standard for Building Carbon Emission Calculation（GB/T 51366-2019）， demonstrating evident decarbonization of these steel products over the past five years. 3） Compared to the carbon emission factors reported in the 2004 literature， the values calculated in this study show a reduction of more than 1300 kg CO2e/t for steel rebars， section steel， and steel plates， demonstrating the remarkable progress in the green and low-carbon development of structural steel products in China over the past two decades.
2025, 55(5): 181-189.
doi: 10.3724/j.gyjzG23030904
Abstract:
In order to study the mechanical properties of basalt fiber reinforced polymer （BFRP）-confined square steel tubular mortar specimens under axial compression， static axial compression tests were conducted on nine specimens with different BFRP layers and section heights. The characteristics of the load-square steel tube longitudinal strain （displacement） curve， failure mode， ultimate bearing capacity， and synergistic reaction between the square steel tube and BFRP were analyzed. ABAQUS simulations were used to obtain the nominal compressive stress-square steel tube longitudinal strain curves and deformation modes of the specimens. The effects of BFRP layers， square steel tube cross-sectional height， and other factors on the static performance of the specimens were investigated and discussed. Additionally， the effects of the number of BFRP layers and the height of the square steel tube section on the static performance of the specimens were explored. Based on performance analysis， the axial compressive strength （fbfscy） of BFRP-confined square steel tubular mortar specimens was defined and fitted to obtain the formula for calculating their ultimate bearing capacity under axial compression. Applying this formula to optimize the ultimate bearing capacity of reinforced components in tunnel lining engineering， using the commonly-used Ι16 I-beam as the benchmark for replacement， and considering economic efficiency and space occupancy， this paper propose optimized parameters for reinforced components （w=54.2 mm、m=3、fy=235 MPa、fcu=80 MPa、fbf=3092 MPa）.
In order to study the mechanical properties of basalt fiber reinforced polymer （BFRP）-confined square steel tubular mortar specimens under axial compression， static axial compression tests were conducted on nine specimens with different BFRP layers and section heights. The characteristics of the load-square steel tube longitudinal strain （displacement） curve， failure mode， ultimate bearing capacity， and synergistic reaction between the square steel tube and BFRP were analyzed. ABAQUS simulations were used to obtain the nominal compressive stress-square steel tube longitudinal strain curves and deformation modes of the specimens. The effects of BFRP layers， square steel tube cross-sectional height， and other factors on the static performance of the specimens were investigated and discussed. Additionally， the effects of the number of BFRP layers and the height of the square steel tube section on the static performance of the specimens were explored. Based on performance analysis， the axial compressive strength （fbfscy） of BFRP-confined square steel tubular mortar specimens was defined and fitted to obtain the formula for calculating their ultimate bearing capacity under axial compression. Applying this formula to optimize the ultimate bearing capacity of reinforced components in tunnel lining engineering， using the commonly-used Ι16 I-beam as the benchmark for replacement， and considering economic efficiency and space occupancy， this paper propose optimized parameters for reinforced components （w=54.2 mm、m=3、fy=235 MPa、fcu=80 MPa、fbf=3092 MPa）.
2025, 55(5): 190-200.
doi: 10.3724/j.gyjzG24091601
Abstract:
To study the seismic performance of frames with cantilever beam segments in different connection types， 12 planar frames with four different connection types were designed. A simplified model of these frames was established based on the beam-column connection simplification theory. First， a simplified model of the double-flanged plane frame from the literature was established， and quasi-static and quasi-dynamic numerical calculations were carried out. The results showed that the hysteresis curves， skeleton curves， and the maximum displacement of the column top were in good agreement with the experimental results. Based on the reliability of the simplified beam-column connection model， a dynamic time-history analysis of 12 framework simplified models was carried out by using ABAQUS software. By comparing the natural vibration periods， inter-story drift angles， column-top displacement time-history curves， and column-bottom shear time-history curves of the frame， the seismic performance of four types of cantilever beam-connected frames was analyzed. The results showed that the 6-story frame with the reinforced embedded connection with cantilever beam exhibited good seismic performance， but its energy dissipation capacity was poor， and the seismic performance decreased with the increase of the number of frames. The frame with the traditional butt connection and cantilever beam exhibited better seismic performance， but strengthening measures should be taken at the weak layer. There was little difference in seismic performance between the frames with embedded bolted connections and embedded bolt-welded hybrid connections. The energy dissipation at the connection was reduced by welding the flange between the cantilever beam and the main beam.
To study the seismic performance of frames with cantilever beam segments in different connection types， 12 planar frames with four different connection types were designed. A simplified model of these frames was established based on the beam-column connection simplification theory. First， a simplified model of the double-flanged plane frame from the literature was established， and quasi-static and quasi-dynamic numerical calculations were carried out. The results showed that the hysteresis curves， skeleton curves， and the maximum displacement of the column top were in good agreement with the experimental results. Based on the reliability of the simplified beam-column connection model， a dynamic time-history analysis of 12 framework simplified models was carried out by using ABAQUS software. By comparing the natural vibration periods， inter-story drift angles， column-top displacement time-history curves， and column-bottom shear time-history curves of the frame， the seismic performance of four types of cantilever beam-connected frames was analyzed. The results showed that the 6-story frame with the reinforced embedded connection with cantilever beam exhibited good seismic performance， but its energy dissipation capacity was poor， and the seismic performance decreased with the increase of the number of frames. The frame with the traditional butt connection and cantilever beam exhibited better seismic performance， but strengthening measures should be taken at the weak layer. There was little difference in seismic performance between the frames with embedded bolted connections and embedded bolt-welded hybrid connections. The energy dissipation at the connection was reduced by welding the flange between the cantilever beam and the main beam.
2025, 55(5): 201-207.
doi: 10.3724/j.gyjzG23082412
Abstract:
During the service of engineering structures such as high-rise buildings， viaducts， and marine platforms， pile foundations typically bear complex jmlateral and vertical loads. Existing research often overlooks the impact of the coupling effect of multi-directional loads on the lateral deformation of pile foundations. This study considered a single pile as a finite-length Euler-Bernoulli beam and proposed an analytical solution for its mechanical response under the influence of coupled multi-directional loads， which had been validated through ABAQUS finite element simulations. The results showed that the influence of vertical loads on lateral displacement and bending moments increased with the increase of horizontal loads. An increase in both horizontal and vertical loads resulted to greater lateral displacement and bending moments， with the impact of horizontal loads being more significant. A coupling effect was observed between bending moments and vertical loads， and its influence increased with higher bending moments.An increase in the soil’s elastic modulus reduced the displacement of the pile foundation， with a greater impact on the internal forces than on the lateral displacement.
During the service of engineering structures such as high-rise buildings， viaducts， and marine platforms， pile foundations typically bear complex jmlateral and vertical loads. Existing research often overlooks the impact of the coupling effect of multi-directional loads on the lateral deformation of pile foundations. This study considered a single pile as a finite-length Euler-Bernoulli beam and proposed an analytical solution for its mechanical response under the influence of coupled multi-directional loads， which had been validated through ABAQUS finite element simulations. The results showed that the influence of vertical loads on lateral displacement and bending moments increased with the increase of horizontal loads. An increase in both horizontal and vertical loads resulted to greater lateral displacement and bending moments， with the impact of horizontal loads being more significant. A coupling effect was observed between bending moments and vertical loads， and its influence increased with higher bending moments.An increase in the soil’s elastic modulus reduced the displacement of the pile foundation， with a greater impact on the internal forces than on the lateral displacement.
2025, 55(5): 208-216.
doi: 10.3724/j.gyjzG23083129
Abstract:
In order to solve the problems of low early strength and poor water stability in lime-fly ash soil （a mixture of lime， fly ash， and red clay）， while considering the recycling of solid waste phosphogypsum， the study investigated the effects of phosphogypsum on the mechanical properties of lime-fly ash soil by indoor tests， and the microstructural characteristics and compositional changes of lime-fly ash soil before and after improvement were analyzed by scanning electron microscope tests and X-ray diffraction tests. The results revealed that phosphogypsum significantly enhanced the soil's early strength and water stability. With increasing phosphogypsum dosage， the soil’s unconfined compressive strength （UCS） initially increased and then decreased. The optimal mix（lime∶fly ash∶phosphogypsum=1∶2∶0.5） achieved peak strength at 8% lime addition， with UCS increasing by 67.2% at 7 days and tripling at 28 days. After saturation， the 7-day cured specimens showed no significant visual changes but demonstrated improved disintegration resistance. The water stability coefficient was elevated by 43%， reaching 0.91 at 28 days. SEM analysis demonstrated that phosphogypsum addition promoted the formation of new hydration products， transforming the soil structure from discrete granular particles into a denser cementitious network. XRD analysis identified these products as ettringite， which contributed to the soil’s strength enhancement.
In order to solve the problems of low early strength and poor water stability in lime-fly ash soil （a mixture of lime， fly ash， and red clay）， while considering the recycling of solid waste phosphogypsum， the study investigated the effects of phosphogypsum on the mechanical properties of lime-fly ash soil by indoor tests， and the microstructural characteristics and compositional changes of lime-fly ash soil before and after improvement were analyzed by scanning electron microscope tests and X-ray diffraction tests. The results revealed that phosphogypsum significantly enhanced the soil's early strength and water stability. With increasing phosphogypsum dosage， the soil’s unconfined compressive strength （UCS） initially increased and then decreased. The optimal mix（lime∶fly ash∶phosphogypsum=1∶2∶0.5） achieved peak strength at 8% lime addition， with UCS increasing by 67.2% at 7 days and tripling at 28 days. After saturation， the 7-day cured specimens showed no significant visual changes but demonstrated improved disintegration resistance. The water stability coefficient was elevated by 43%， reaching 0.91 at 28 days. SEM analysis demonstrated that phosphogypsum addition promoted the formation of new hydration products， transforming the soil structure from discrete granular particles into a denser cementitious network. XRD analysis identified these products as ettringite， which contributed to the soil’s strength enhancement.
2025, 55(5): 217-225.
doi: 10.3724/j.gyjzG23050303
Abstract:
Based on the demand for three-dimensional urban development， the number and scale of subway superstructure projects are gradually increasing， which has a significant impact on existing subway stations and tunnels during the construction process in Tianjin’s soft soil areas. Taking the existing subway station topping project of Tianjin Subway Line 5 as a case study， the paper analyzed the entire excavation process， including pre-excavation dewatering， based on the measurement data. It further studied the impact of deep and large excavations with simultaneous two-sided excavation on existing subway stations and tunnels. A deformation control method for existing structures during construction by refining the dewatering scheme was proposed. The study showed that： 1） Simultaneous deep and large excavations on both sides exerted a huge impact on the existing subway station and tunnel structures between them. The vertical displacement of the existing structures risked exceeding the alarm value or even the control value. Additionally， the vertical and horizontal deformation patterns differed significantly between the existing structure and the new diaphragm wall： during the excavation process， the main structure of the station experienced continuous heave， while the diaphragm wall initially settled but transitioned to heave upon reaching the final excavation depth， with both structures ultimately reaching a similar heave value of approximately 11.0 mm. In terms of horizontal deformation， the newly constructed diaphragm wall exhibited progressively increasing outward displacement as excavation progressed， whereas the station structure showed an initial increase followed by a gradual reduction in horizontal displacement， resulting in a final horizontal displacement of the diaphragm wall that was more than twice that of the station structure. 2） The influence of dewatering in the excavation on the main body of the existing structure and the new diaphragm wall had a large difference. By formulating a refined dewatering scheme， controlled pre-settlement of the station structure could be achieved before excavation. This approach effectively minimized construction-induced heave of the existing station while ensuring compliance with deformation control standards for the new diaphragm wall and supporting structures， thereby guaranteeing construction safety.
Based on the demand for three-dimensional urban development， the number and scale of subway superstructure projects are gradually increasing， which has a significant impact on existing subway stations and tunnels during the construction process in Tianjin’s soft soil areas. Taking the existing subway station topping project of Tianjin Subway Line 5 as a case study， the paper analyzed the entire excavation process， including pre-excavation dewatering， based on the measurement data. It further studied the impact of deep and large excavations with simultaneous two-sided excavation on existing subway stations and tunnels. A deformation control method for existing structures during construction by refining the dewatering scheme was proposed. The study showed that： 1） Simultaneous deep and large excavations on both sides exerted a huge impact on the existing subway station and tunnel structures between them. The vertical displacement of the existing structures risked exceeding the alarm value or even the control value. Additionally， the vertical and horizontal deformation patterns differed significantly between the existing structure and the new diaphragm wall： during the excavation process， the main structure of the station experienced continuous heave， while the diaphragm wall initially settled but transitioned to heave upon reaching the final excavation depth， with both structures ultimately reaching a similar heave value of approximately 11.0 mm. In terms of horizontal deformation， the newly constructed diaphragm wall exhibited progressively increasing outward displacement as excavation progressed， whereas the station structure showed an initial increase followed by a gradual reduction in horizontal displacement， resulting in a final horizontal displacement of the diaphragm wall that was more than twice that of the station structure. 2） The influence of dewatering in the excavation on the main body of the existing structure and the new diaphragm wall had a large difference. By formulating a refined dewatering scheme， controlled pre-settlement of the station structure could be achieved before excavation. This approach effectively minimized construction-induced heave of the existing station while ensuring compliance with deformation control standards for the new diaphragm wall and supporting structures， thereby guaranteeing construction safety.
2025, 55(5): 226-238.
doi: 10.3724/j.gyjzG23042604
Abstract:
Q3 loess is a kind of loess with strong collapsibility. After soaking and saturation in water， its collapsibility disappears and then converts into a high compressibility soil. Generally， it is in an undercompacted state under natural conditions， exhibiting high compressibility， large deformation， low bearing capacity， poor engineering performance， etc.， which is easy to lead to engineering accidents. The stress-strain relations and strength characteristics of Q3 loess with continuous humidification under different initial overburden loads were studied by conventional triaxial tests with GDS unsaturated soil triaxial apparatus. The results showed that the stress-strain curves of Q3 loess were hardened in the process of continuous humidification. The smaller the degree of humidification， the greater the consolidation pressure， and the higher the stress-strain curve； when the initial overburden load was 0 to 100 kPa， the rise of the stress-strain curve was low and flat， and when it was greater than 100 kPa， the rise of the stress-strain curve gradually steepened. Under all test conditions， the failure line of p-q strength was approximately linear； the strength of Q3 loess was closely related to its water content and initial overburden load. With the increase of water content， both cohesion and internal friction angle exhibited nonlinear attenuation； with the increase of the initial overburden load， they first decreased and then increased.
Q3 loess is a kind of loess with strong collapsibility. After soaking and saturation in water， its collapsibility disappears and then converts into a high compressibility soil. Generally， it is in an undercompacted state under natural conditions， exhibiting high compressibility， large deformation， low bearing capacity， poor engineering performance， etc.， which is easy to lead to engineering accidents. The stress-strain relations and strength characteristics of Q3 loess with continuous humidification under different initial overburden loads were studied by conventional triaxial tests with GDS unsaturated soil triaxial apparatus. The results showed that the stress-strain curves of Q3 loess were hardened in the process of continuous humidification. The smaller the degree of humidification， the greater the consolidation pressure， and the higher the stress-strain curve； when the initial overburden load was 0 to 100 kPa， the rise of the stress-strain curve was low and flat， and when it was greater than 100 kPa， the rise of the stress-strain curve gradually steepened. Under all test conditions， the failure line of p-q strength was approximately linear； the strength of Q3 loess was closely related to its water content and initial overburden load. With the increase of water content， both cohesion and internal friction angle exhibited nonlinear attenuation； with the increase of the initial overburden load， they first decreased and then increased.
2025, 55(5): 239-247.
doi: 10.3724/j.gyjzG23032904
Abstract:
Taking sandstone-like samples containing two non-coplanar fissures as the research object， uniaxial compression tests and PFC2D numerical simulations were carried out to study the mechanical properties and energy evolution laws of rock specimens under different fissure dip angles α. The results showed that as the fissure dip angle increased， the crack initiation， damage， and peak stress of the sample first decreased and then increased， while the crack fracture zone decreased. By analyzing the internal relationship between the number of microcracks and energy during the loading process of the sample， it was revealed that the failure of the sample was a gradual failure process of bearing capacity. Both the number of microcracks and the energy of the sample first decreased and then increased with the increase of fissure dip angle. The elastic energy dissipation ratio K of rock samples was introduced， which confirmed that the mutability of K could be used as one of the characteristic parameters of rock instability and failure， and the brittleness index correction coefficient of rock specimens could reflect the brittle failure characteristics and energy release characteristics of rock samples.
Taking sandstone-like samples containing two non-coplanar fissures as the research object， uniaxial compression tests and PFC2D numerical simulations were carried out to study the mechanical properties and energy evolution laws of rock specimens under different fissure dip angles α. The results showed that as the fissure dip angle increased， the crack initiation， damage， and peak stress of the sample first decreased and then increased， while the crack fracture zone decreased. By analyzing the internal relationship between the number of microcracks and energy during the loading process of the sample， it was revealed that the failure of the sample was a gradual failure process of bearing capacity. Both the number of microcracks and the energy of the sample first decreased and then increased with the increase of fissure dip angle. The elastic energy dissipation ratio K of rock samples was introduced， which confirmed that the mutability of K could be used as one of the characteristic parameters of rock instability and failure， and the brittleness index correction coefficient of rock specimens could reflect the brittle failure characteristics and energy release characteristics of rock samples.
2025, 55(5): 248-261.
doi: 10.3724/j.gyjzG23070105
Abstract:
This study provides a comprehensive review of the current research on the propagation and attenuation of site vibrations induced by industrial sources. The exposition began by elucidating the definition， classification， and load forms associated with industrial sources. Subsequently， two analytical methods were summarized based on these studies： prediction and testing approaches for vibration propagation and attenuation. The discussion then elaborated on theoretical analysis prediction， empirical formula prediction， and numerical simulation prediction within the domain of vibration propagation attenuation prediction methods. Additionally， it delved into the current landscape of empirical testing methods in analytical studies. Finally， drawing upon a literature review， this paper explored pressing issues in the analysis of vibration propagation attenuation under the influence of industrial sources， providing forward-looking perspectives. This endeavor aims to stimulate the advancement of research in the realm of vibration propagation attenuation induced by industrial sources and to provide means of support for micro-vibration prevention and control within site regions， thereby enhancing environmental comfort.
This study provides a comprehensive review of the current research on the propagation and attenuation of site vibrations induced by industrial sources. The exposition began by elucidating the definition， classification， and load forms associated with industrial sources. Subsequently， two analytical methods were summarized based on these studies： prediction and testing approaches for vibration propagation and attenuation. The discussion then elaborated on theoretical analysis prediction， empirical formula prediction， and numerical simulation prediction within the domain of vibration propagation attenuation prediction methods. Additionally， it delved into the current landscape of empirical testing methods in analytical studies. Finally， drawing upon a literature review， this paper explored pressing issues in the analysis of vibration propagation attenuation under the influence of industrial sources， providing forward-looking perspectives. This endeavor aims to stimulate the advancement of research in the realm of vibration propagation attenuation induced by industrial sources and to provide means of support for micro-vibration prevention and control within site regions， thereby enhancing environmental comfort.
2025, 55(5): 262-269.
doi: 10.3724/j.gyjzG24050805
Abstract:
Saline soil environments contain large amounts of erosion salts such as sulfates and chloride salts， which will have an important impact on the performance of UHPC. In this paper， an environmental erosion simulation system for western saline soils was formulated， and indoor accelerated erosion tests were designed to explore the performance degradation laws of UHPC under sulfate erosion and sulfate-chloride composite erosion. Microscopic testing methods such as XRD， TG-DTG， SEM and MIP revealed the degradation mechanism of UHPC under different salt erosion conditions. The results showed that after 240 d of sulfate-chloride composite erosion， the surface of the specimen appeared to flake off， and more holes were produced and a large number of salt crystals were precipitated. Compared with the uneroded specimen， its compressive strength， flexural strength， equivalent bending toughness and relative dynamic elastic modulus were reduced by 7.36%， 25.49%， 10.87%， and 97.83%， respectively. At the end of composite salt erosion， the characteristic peaks of ettringite and gypsum in the specimen were stronger than those under sulfate erosion condition， and a large number of needle-like ettringite crystals were formed inside， and the expansion stress generated led to the appearance of more penetrating cracks and connected pores inside the structure. After composite salt erosion， the proportion of harmful pores such as capillary pores and macropores increased， while the number of gel pores decreased relatively， which had a greater impact on the pore structure than the sulfate-eroded specimen.
Saline soil environments contain large amounts of erosion salts such as sulfates and chloride salts， which will have an important impact on the performance of UHPC. In this paper， an environmental erosion simulation system for western saline soils was formulated， and indoor accelerated erosion tests were designed to explore the performance degradation laws of UHPC under sulfate erosion and sulfate-chloride composite erosion. Microscopic testing methods such as XRD， TG-DTG， SEM and MIP revealed the degradation mechanism of UHPC under different salt erosion conditions. The results showed that after 240 d of sulfate-chloride composite erosion， the surface of the specimen appeared to flake off， and more holes were produced and a large number of salt crystals were precipitated. Compared with the uneroded specimen， its compressive strength， flexural strength， equivalent bending toughness and relative dynamic elastic modulus were reduced by 7.36%， 25.49%， 10.87%， and 97.83%， respectively. At the end of composite salt erosion， the characteristic peaks of ettringite and gypsum in the specimen were stronger than those under sulfate erosion condition， and a large number of needle-like ettringite crystals were formed inside， and the expansion stress generated led to the appearance of more penetrating cracks and connected pores inside the structure. After composite salt erosion， the proportion of harmful pores such as capillary pores and macropores increased， while the number of gel pores decreased relatively， which had a greater impact on the pore structure than the sulfate-eroded specimen.
2025, 55(5): 270-279.
doi: 10.3724/j.gyjzG24071902
Abstract:
The interfacial bonding strength and failure mechanism of magnesium phosphate cement （MPC） mortar and ordinary concrete （NC） are very important for the structural performance of MPC mortar to reinforce NC. In this paper， the double-sided shear test was used to study the influence of four different interface types on the bonding properties of the MPC mortar-NC interface， the failure process of the specimen was observed， the relationship curve between the bond strength and the slip amount was obtained， the failure mode and failure mechanism of the specimen were analyzed. The effects of curing ages（7 days and 28 days） as well as different compressive strengths （60 MPa and 55 MPa） on the interface bonding properties were compared. On the basis of theoretical analysis and combined with the experimental data， a calculation formula for the shear capacity of the bonded interface was proposed， suitable for different interface treatment conditions. In addition， a two-line constitutive model was established for the non-planting interface， and a three-line constitutive model was developed for the planting interface. This study provides theoretical support and design basis for the application of MPC in structural reinforcement engineering.
The interfacial bonding strength and failure mechanism of magnesium phosphate cement （MPC） mortar and ordinary concrete （NC） are very important for the structural performance of MPC mortar to reinforce NC. In this paper， the double-sided shear test was used to study the influence of four different interface types on the bonding properties of the MPC mortar-NC interface， the failure process of the specimen was observed， the relationship curve between the bond strength and the slip amount was obtained， the failure mode and failure mechanism of the specimen were analyzed. The effects of curing ages（7 days and 28 days） as well as different compressive strengths （60 MPa and 55 MPa） on the interface bonding properties were compared. On the basis of theoretical analysis and combined with the experimental data， a calculation formula for the shear capacity of the bonded interface was proposed， suitable for different interface treatment conditions. In addition， a two-line constitutive model was established for the non-planting interface， and a three-line constitutive model was developed for the planting interface. This study provides theoretical support and design basis for the application of MPC in structural reinforcement engineering.
2025, 55(5): 280-291.
doi: 10.3724/j.gyjzG24040506
Abstract:
To prepare a low-carbon and cost-effective high-strength and high-ductility concrete （ HS-HDC ）， the paper designed 16 groups of orthogonal tests with 5 factors and 4 levels of coal gangue powder， silica fume， PVA fibers， water-binder ratio， and sand-binder ratio， three tests of uniaxial compression， four-point bending， and electron microscope scanning were carried out to explore the influence of each factor on the mechanical properties of HS-HDC and its microscopic mechanism. The test results showed that the integrity of the uniaxial compression failure specimen was good. When the fiber volume content was not less than 1.0%， the surface cracks of the failure specimen were vertically distributed， and the higher the fiber content， the smaller the surface crack width of the specimen. The coal gangue powder and water-binder ratio significantly affected the compressive strength， with contribution rates of 44.83% and 33.56%， respectively. The four-point bending specimen exhibited two failure forms： single crack and multiple cracks， demonstrating a typical three-stage failure mode. Only PVA fibers had a significant effect on the bending strength， with a contribution rate of 66.10%. The comprehensive mechanical properties of the H5 mixture ratio （ coal gangue powder 0.6， silica fume 0.14， PVA fibers 1.7%， water-binder ratio 0.3， sand-binder ratio 0.5 ） were the best. The cubic compressive strength was 69.0 MPa， the flexural strength was 19.7 MPa， the equivalent flexural toughness was 108.9 kJ/m3， and the tensile strain capacity was 1.05%. Cement and fibers were the two most critical components that affected embodied energy and embodied carbon. Using solid waste to replace part of cement was a very effective way to reduce carbon emissions.
To prepare a low-carbon and cost-effective high-strength and high-ductility concrete （ HS-HDC ）， the paper designed 16 groups of orthogonal tests with 5 factors and 4 levels of coal gangue powder， silica fume， PVA fibers， water-binder ratio， and sand-binder ratio， three tests of uniaxial compression， four-point bending， and electron microscope scanning were carried out to explore the influence of each factor on the mechanical properties of HS-HDC and its microscopic mechanism. The test results showed that the integrity of the uniaxial compression failure specimen was good. When the fiber volume content was not less than 1.0%， the surface cracks of the failure specimen were vertically distributed， and the higher the fiber content， the smaller the surface crack width of the specimen. The coal gangue powder and water-binder ratio significantly affected the compressive strength， with contribution rates of 44.83% and 33.56%， respectively. The four-point bending specimen exhibited two failure forms： single crack and multiple cracks， demonstrating a typical three-stage failure mode. Only PVA fibers had a significant effect on the bending strength， with a contribution rate of 66.10%. The comprehensive mechanical properties of the H5 mixture ratio （ coal gangue powder 0.6， silica fume 0.14， PVA fibers 1.7%， water-binder ratio 0.3， sand-binder ratio 0.5 ） were the best. The cubic compressive strength was 69.0 MPa， the flexural strength was 19.7 MPa， the equivalent flexural toughness was 108.9 kJ/m3， and the tensile strain capacity was 1.05%. Cement and fibers were the two most critical components that affected embodied energy and embodied carbon. Using solid waste to replace part of cement was a very effective way to reduce carbon emissions.
2025, 55(5): 292-301.
doi: 10.3724/j.gyjzG24122004
Abstract:
In order to study the carbon absorption capacity of concrete under load， X-ray diffraction（XRD）， therrmogravimetry（TG） and mercury intrusion porosimetry（MIP） were used to explain the influence of different carbonization treatment time and load level on the mechanics and carbon absorption capacity of concrete.The grey entropy analysis method was used to analyze the effect of different pore structures on the CO2 uptake of concrete. The results show that the CO2 uptake in the compressive zone of concrete under different load levels increases first and then flat with the increase of carbonization time.In the early stage of carbonization treatment， the number of the most probable pore size and macropores of concrete increased， and the CO2 uptake increases. In the middle stage of carbonization treatment， the most probable pore size decreases， and the CO2 uptake tends to be gentle. In the later stage of carbonization treatment， the porosity decreases， the pore tortuosity increases， and the CO2 uptake tends to be gentle. The order of influence on the CO2 uptake of concrete is pore tortuosity > most probable pore size > porosity. When the concrete under the combined action of load and carbonization treatment is at a higher load level， the connectivity of concrete pores and the amount of CO2 uptake increase. The number of large pores in the compressive zone of concrete under 60 % load level increases with the increase of carbonization treatment time， and its carbon absorption capacity is the best. The order of influence on the CO2 uptake of concrete is macropore > large pores > gelpores > medium pores.
In order to study the carbon absorption capacity of concrete under load， X-ray diffraction（XRD）， therrmogravimetry（TG） and mercury intrusion porosimetry（MIP） were used to explain the influence of different carbonization treatment time and load level on the mechanics and carbon absorption capacity of concrete.The grey entropy analysis method was used to analyze the effect of different pore structures on the CO2 uptake of concrete. The results show that the CO2 uptake in the compressive zone of concrete under different load levels increases first and then flat with the increase of carbonization time.In the early stage of carbonization treatment， the number of the most probable pore size and macropores of concrete increased， and the CO2 uptake increases. In the middle stage of carbonization treatment， the most probable pore size decreases， and the CO2 uptake tends to be gentle. In the later stage of carbonization treatment， the porosity decreases， the pore tortuosity increases， and the CO2 uptake tends to be gentle. The order of influence on the CO2 uptake of concrete is pore tortuosity > most probable pore size > porosity. When the concrete under the combined action of load and carbonization treatment is at a higher load level， the connectivity of concrete pores and the amount of CO2 uptake increase. The number of large pores in the compressive zone of concrete under 60 % load level increases with the increase of carbonization treatment time， and its carbon absorption capacity is the best. The order of influence on the CO2 uptake of concrete is macropore > large pores > gelpores > medium pores.
