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2025 Vol. 55, No. 9
Display Method:
2025, 55(9): 1-7.
doi: 10.3724/j.gyjzG25061101
Abstract:
Using the MMS-200 thermal simulation testing machine， the microstructure of the heat-affected zone （HAZ） of the Q420qENH steel matrix in Q420qENH composite steel plates was determined under different t8/5 cooling speeds. Based on microstructural observation and hardness analysis， the microstructural and hardness changes of the weld heat-affected zone （HAZ） of Q420qENH steel were determined at different t8/5 cooling speeds， and the continuous cooling transformation （CCT） curves of the weld HAZ were plotted. The results showed that when the t8/5 cooling rate was between 1 ℃/s and 10 ℃/s， the transformation products of the test steel were F+GB， and there were no significant changes in grain size and hardness as the cooling rate increased； When the t8/5 cooling rate was between 15 ℃/s and 45 ℃/s， the transformation products of the test steel were ferrite and lower bainite， with grain size decreasing and hardness increasing. Among these， Q420qENH steel exhibited the highest grain size and hardness at a cooling rate of 15 ℃/s. To ensure that the welded joint meets performance requirements， when welding Q420qENH steel base material， the cooling rate should be controlled between 1 ℃/s and 45 ℃/s， with corresponding weld heat input controlled within a range of 7.2 kJ/cm to 48.0 kJ/cm.
Using the MMS-200 thermal simulation testing machine， the microstructure of the heat-affected zone （HAZ） of the Q420qENH steel matrix in Q420qENH composite steel plates was determined under different t8/5 cooling speeds. Based on microstructural observation and hardness analysis， the microstructural and hardness changes of the weld heat-affected zone （HAZ） of Q420qENH steel were determined at different t8/5 cooling speeds， and the continuous cooling transformation （CCT） curves of the weld HAZ were plotted. The results showed that when the t8/5 cooling rate was between 1 ℃/s and 10 ℃/s， the transformation products of the test steel were F+GB， and there were no significant changes in grain size and hardness as the cooling rate increased； When the t8/5 cooling rate was between 15 ℃/s and 45 ℃/s， the transformation products of the test steel were ferrite and lower bainite， with grain size decreasing and hardness increasing. Among these， Q420qENH steel exhibited the highest grain size and hardness at a cooling rate of 15 ℃/s. To ensure that the welded joint meets performance requirements， when welding Q420qENH steel base material， the cooling rate should be controlled between 1 ℃/s and 45 ℃/s， with corresponding weld heat input controlled within a range of 7.2 kJ/cm to 48.0 kJ/cm.
2025, 55(9): 8-20.
doi: 10.3724/j.gyjzG25061104
Abstract:
With the increasing application of high-performance weather-resistant/stainless steel composite panels in the construction of bridges on plateaus with complex environment， welding of high-performance composite panels has become a key link. The welding process of high-performance S31603/Q420qENH composite steel plates was studied， and the composite test plates were welded using the independently developed base-layer weathering flux core welding wire JWT60NHQ， transition layer JWE309LMoT1-1 flux core welding wire， and cladding JWE316LT1-1 flux core welding wire， and the optimal welding process control plan was formulated to ensure the acquisition of stable welding joints. This study obtained transition layer welding materials with different ferrite contents through design and adjustment of the formula， analyzed the impact of the ferrite content of the transition layer welding material on various properties of the composite board joints， and tested the element distribution in each area of the welded joint， joint hardness， impact performance of -40 ℃， corrosion resistance， etc.Comprehensive analysis obtained the optimal welding process system， and it was concluded that when the ferrite number FN in the welded metal of the transition layer welding material was 10~13 （ferrite content was 10.8%~14.3%）， it can provide guarantee for the performance's stability of the composite panel joints.
With the increasing application of high-performance weather-resistant/stainless steel composite panels in the construction of bridges on plateaus with complex environment， welding of high-performance composite panels has become a key link. The welding process of high-performance S31603/Q420qENH composite steel plates was studied， and the composite test plates were welded using the independently developed base-layer weathering flux core welding wire JWT60NHQ， transition layer JWE309LMoT1-1 flux core welding wire， and cladding JWE316LT1-1 flux core welding wire， and the optimal welding process control plan was formulated to ensure the acquisition of stable welding joints. This study obtained transition layer welding materials with different ferrite contents through design and adjustment of the formula， analyzed the impact of the ferrite content of the transition layer welding material on various properties of the composite board joints， and tested the element distribution in each area of the welded joint， joint hardness， impact performance of -40 ℃， corrosion resistance， etc.Comprehensive analysis obtained the optimal welding process system， and it was concluded that when the ferrite number FN in the welded metal of the transition layer welding material was 10~13 （ferrite content was 10.8%~14.3%）， it can provide guarantee for the performance's stability of the composite panel joints.
2025, 55(9): 21-28.
doi: 10.3724/j.gyjzG25042207
Abstract:
Compared with conventional bridge steel， weather-resistant bridge steel takes both mechanical properties and weather resistance into account， and has a promising application prospect in steel bridge engineering. However， the addition of alloy elements has a certain impact on the welding performance. For Q550qENH weather-resistant bridge steel plates， a series of experimental study was conducted， including material reinspection test， welding material reinspection test， steel plate welding performance test， a series of temperature impact test for butt joints， and welding process qualification test for typical joints. The matching welding materials for Q550qENH weather-resistant bridge steel plates were determined. The welding performance and weather resistance of this steel grade were evaluated and analyzed. And welding process qualification tests were carried out according to relevant standards. The test results showed that the -40 ℃ low-temperature impact energy AkV2 of the weld metal was above 54 J， and the value of the corrosion resistance index I was above 6.5， which met the requirements of the relevant steel bridge manufacturing specifications. This provided technical support for the promotion and application of weather-resistant bridge steel in large-scale bridges.
Compared with conventional bridge steel， weather-resistant bridge steel takes both mechanical properties and weather resistance into account， and has a promising application prospect in steel bridge engineering. However， the addition of alloy elements has a certain impact on the welding performance. For Q550qENH weather-resistant bridge steel plates， a series of experimental study was conducted， including material reinspection test， welding material reinspection test， steel plate welding performance test， a series of temperature impact test for butt joints， and welding process qualification test for typical joints. The matching welding materials for Q550qENH weather-resistant bridge steel plates were determined. The welding performance and weather resistance of this steel grade were evaluated and analyzed. And welding process qualification tests were carried out according to relevant standards. The test results showed that the -40 ℃ low-temperature impact energy AkV2 of the weld metal was above 54 J， and the value of the corrosion resistance index I was above 6.5， which met the requirements of the relevant steel bridge manufacturing specifications. This provided technical support for the promotion and application of weather-resistant bridge steel in large-scale bridges.
2025, 55(9): 29-41.
doi: 10.3724/j.gyjzG25031302
Abstract:
In high-altitude corrosive environments， weathering steel is extensively utilized due to its superior corrosion resistance. However， welded joint regions， characterized by altered chemical compositions and microstructures， are prone to attack by corrosive media， leading to mechanical property degradation. This study investigates 16 mm-thick Q500qENH base metal and V-shaped/Y-shaped welded joint specimens using a cyclic immersion corrosion test designed to replicate the realistic dry-wet alternating conditions of plateau environments. Monotonic tensile tests were subsequently performed on specimens subjected to varying corrosion durations. Through comprehensive analysis of fracture locations， yield load， ultimate load， yield strength， and tensile strength， the performance degradation mechanism of weathering steel welded joints under typical high-altitude corrosion was elucidated. The results demonstrated that welding reduced corrosion resistance and enhanced brittleness， evidenced by greater mechanical property degradation in welded joints compared to base metal specimens. For the base metal， its strength degraded rapidly in the early stage of corrosion， while the degradation rate slowed down in the later stage due to the densification of the rust layer. Among the welded joints， Y-shaped joints were the most sensitive to corrosion but had the highest initial strength. Most specimens exhibited ductile failure， and only some V-shaped joints showed brittle fracture after 27 days of corrosion.In this study， a predictive model for the yield strength of the base metal （applicable to an average corrosion rate range of 0~3%） was established. Additionally， a strength reduction factor of 0.97 （corresponding to a corrosion rate of 2.30%） was proposed as the maintenance threshold. This research provides a reference for the engineering design of weathering steel structures in plateau environments.
In high-altitude corrosive environments， weathering steel is extensively utilized due to its superior corrosion resistance. However， welded joint regions， characterized by altered chemical compositions and microstructures， are prone to attack by corrosive media， leading to mechanical property degradation. This study investigates 16 mm-thick Q500qENH base metal and V-shaped/Y-shaped welded joint specimens using a cyclic immersion corrosion test designed to replicate the realistic dry-wet alternating conditions of plateau environments. Monotonic tensile tests were subsequently performed on specimens subjected to varying corrosion durations. Through comprehensive analysis of fracture locations， yield load， ultimate load， yield strength， and tensile strength， the performance degradation mechanism of weathering steel welded joints under typical high-altitude corrosion was elucidated. The results demonstrated that welding reduced corrosion resistance and enhanced brittleness， evidenced by greater mechanical property degradation in welded joints compared to base metal specimens. For the base metal， its strength degraded rapidly in the early stage of corrosion， while the degradation rate slowed down in the later stage due to the densification of the rust layer. Among the welded joints， Y-shaped joints were the most sensitive to corrosion but had the highest initial strength. Most specimens exhibited ductile failure， and only some V-shaped joints showed brittle fracture after 27 days of corrosion.In this study， a predictive model for the yield strength of the base metal （applicable to an average corrosion rate range of 0~3%） was established. Additionally， a strength reduction factor of 0.97 （corresponding to a corrosion rate of 2.30%） was proposed as the maintenance threshold. This research provides a reference for the engineering design of weathering steel structures in plateau environments.
2025, 55(9): 42-52.
doi: 10.3724/j.gyjzG25031303
Abstract:
In order to study the corrosion resistance of Q500qENH weathering steel welded joints in the plateau area， a cyclic immersion corrosion simulation test was carried out for the complex polluted environment dominated by an industrial atmosphere in the Qinghai-Tibet Plateau region. Accelerated corrosion tests were carried out on the base metal specimens， as well as V-type and Y-type welded joint specimens of Q500qENH weathering steel. Four corrosion cycles were set in the test： 0 d， 9 d， 18 d， and 27 d. By comparing the corrosion rate， cross-section loss rate， corrosion velocity， and corrosion depth under different corrosion cycles， the acceleration of the cyclic immersion corrosion test was evaluated. The results showed that the corrosion process of Q500qENH weathering steel had obvious stratification， which was highlighted as a rapid corrosion stage and a slow corrosion stage. Under the same corrosion cycle， the corrosion speed of the welded joint specimens was consistently higher than that of the base metal specimens. However， the difference between them initially increased， then decreased， and eventually stabilized over time. By equivalently converting the results of the cyclic immersion test and the natural atmospheric exposure corrosion test， it was found that the corrosion speed was extremely slow in the complex polluted environment （dominated by an industrial atmosphere in the Qinghai-Tibet Plateau region）， and the corrosion time would be far more than 30 years.
In order to study the corrosion resistance of Q500qENH weathering steel welded joints in the plateau area， a cyclic immersion corrosion simulation test was carried out for the complex polluted environment dominated by an industrial atmosphere in the Qinghai-Tibet Plateau region. Accelerated corrosion tests were carried out on the base metal specimens， as well as V-type and Y-type welded joint specimens of Q500qENH weathering steel. Four corrosion cycles were set in the test： 0 d， 9 d， 18 d， and 27 d. By comparing the corrosion rate， cross-section loss rate， corrosion velocity， and corrosion depth under different corrosion cycles， the acceleration of the cyclic immersion corrosion test was evaluated. The results showed that the corrosion process of Q500qENH weathering steel had obvious stratification， which was highlighted as a rapid corrosion stage and a slow corrosion stage. Under the same corrosion cycle， the corrosion speed of the welded joint specimens was consistently higher than that of the base metal specimens. However， the difference between them initially increased， then decreased， and eventually stabilized over time. By equivalently converting the results of the cyclic immersion test and the natural atmospheric exposure corrosion test， it was found that the corrosion speed was extremely slow in the complex polluted environment （dominated by an industrial atmosphere in the Qinghai-Tibet Plateau region）， and the corrosion time would be far more than 30 years.
2025, 55(9): 53-61.
doi: 10.3724/j.gyjzG25031304
Abstract:
Cyclic immersion corrosion tests simulating industrial atmospheric environments and monotonic tensile tests were conducted on weathering steel welded joints after rust layer stabilization treatment to investigate the influence of rust layer stabilization on the corrosion resistance and mechanical properties of the joints. The results indicated that the stabilization treatment enhanced the compactness of the inner rust layer， effectively suppressed long-term mechanical performance degradation， and provided excellent long-term anti-corrosion effects. Under monotonic tensile loading， all welded joint specimens fractured in the base metal region at a distance of 5-20 mm from the weld， exhibiting significant plastic deformation.
Cyclic immersion corrosion tests simulating industrial atmospheric environments and monotonic tensile tests were conducted on weathering steel welded joints after rust layer stabilization treatment to investigate the influence of rust layer stabilization on the corrosion resistance and mechanical properties of the joints. The results indicated that the stabilization treatment enhanced the compactness of the inner rust layer， effectively suppressed long-term mechanical performance degradation， and provided excellent long-term anti-corrosion effects. Under monotonic tensile loading， all welded joint specimens fractured in the base metal region at a distance of 5-20 mm from the weld， exhibiting significant plastic deformation.
2025, 55(9): 62-72.
doi: 10.3724/j.gyjzG25031305
Abstract:
To investigate the fatigue damage of welded joints in 500qENH weathering steel bridge decks under complex loading conditions， this study employed ABAQUS-Franc 3D cross-platform collaborative simulation technology to model the dynamic crack propagation process， with a particular emphasis on elucidating the influence mechanisms of initial crack morphology （including depth-to-width ratio and inclination angle） and top-plate thickness on crack evolution. Numerical analysis results demonstrated that under vehicular loading， significant spatial heterogeneity of stress intensity factors （SIFs） was observed at vulnerable joints， with mid-span loading representing the most critical loading scenario. Crack propagation paths were predominantly governed by geometric constraint effects， exhibiting a phased evolution pattern characterized by an initial increase followed a by subsequent decrease in the crack depth-to-width ratio， where crack depth exerted more substantial influence on fatigue life than width dimension. Enlargement of initial crack dimensions elevated SIF amplitudes by 18% to 35%. Inclined cracks at 15° manifested 23% higher peak SIF values compared to vertical cracks. Increased top-plate thickness nonlinearly enhanced crack propagation life with progressively accelerated extension rates. Elevated wheel load pressure induced decelerating reduction rates in crack propagation life.
To investigate the fatigue damage of welded joints in 500qENH weathering steel bridge decks under complex loading conditions， this study employed ABAQUS-Franc 3D cross-platform collaborative simulation technology to model the dynamic crack propagation process， with a particular emphasis on elucidating the influence mechanisms of initial crack morphology （including depth-to-width ratio and inclination angle） and top-plate thickness on crack evolution. Numerical analysis results demonstrated that under vehicular loading， significant spatial heterogeneity of stress intensity factors （SIFs） was observed at vulnerable joints， with mid-span loading representing the most critical loading scenario. Crack propagation paths were predominantly governed by geometric constraint effects， exhibiting a phased evolution pattern characterized by an initial increase followed a by subsequent decrease in the crack depth-to-width ratio， where crack depth exerted more substantial influence on fatigue life than width dimension. Enlargement of initial crack dimensions elevated SIF amplitudes by 18% to 35%. Inclined cracks at 15° manifested 23% higher peak SIF values compared to vertical cracks. Increased top-plate thickness nonlinearly enhanced crack propagation life with progressively accelerated extension rates. Elevated wheel load pressure induced decelerating reduction rates in crack propagation life.
2025, 55(9): 73-85.
doi: 10.3724/j.gyjzG25031306
Abstract:
Weathering steel is widely used in plateau construction because of its excellent working performance in complex environment. In order to study the low temperature fatigue performance of welded joints of Q500qENH weathering steel， based on the linear elastic fracture mechanics method and the interactive use of ABAQUS and FRANC3D software， the fatigue crack propagation of V-shaped butt joint and cross shaped transmission angle welded joints at -40 ℃ were simulated. And the model was verified by comparing with low temperature fatigue experimental results. On this basis， several key factors affecting the fatigue life were analyzed. The results showed that： the initial crack size and initial crack angle mainly affected the early crack propagation pattern and the final fatigue life of the welded joints. The fatigue life was minimum when the length of the major and minor axes of the initial elliptical crack was equal， and the initial crack plane was perpendicular to the length of the specimen. The initial crack location in the lengthwise direction of angle welding surface had great influence on the fatigue life of the cross shaped transmission angle welded joints， while had little influence on the V-shaped butt joint.
Weathering steel is widely used in plateau construction because of its excellent working performance in complex environment. In order to study the low temperature fatigue performance of welded joints of Q500qENH weathering steel， based on the linear elastic fracture mechanics method and the interactive use of ABAQUS and FRANC3D software， the fatigue crack propagation of V-shaped butt joint and cross shaped transmission angle welded joints at -40 ℃ were simulated. And the model was verified by comparing with low temperature fatigue experimental results. On this basis， several key factors affecting the fatigue life were analyzed. The results showed that： the initial crack size and initial crack angle mainly affected the early crack propagation pattern and the final fatigue life of the welded joints. The fatigue life was minimum when the length of the major and minor axes of the initial elliptical crack was equal， and the initial crack plane was perpendicular to the length of the specimen. The initial crack location in the lengthwise direction of angle welding surface had great influence on the fatigue life of the cross shaped transmission angle welded joints， while had little influence on the V-shaped butt joint.
2025, 55(9): 86-94.
doi: 10.3724/j.gyjzG25061801
Abstract:
To accurately evaluate the fatigue performance of welded joints in weathering steel bridge decks under the coupling effect of low-temperature environment and multiple vehicle-borne factors， this paper conducted tensile tests and fatigue crack propagation tests on Q500qENH weathering steel specimens under multi-temperature conditions. To verify the test results， corresponding finite element simulations of fatigue crack propagation in the specimens were performed. An orthotropic steel bridge deck finite element model was established to conduct a comparative analysis of the fatigue crack propagation behavior of vulnerable welded joints under multiple constant temperature conditions. Based on this model， the fatigue life prediction of vulnerable welded joints under variable temperature conditions was carried out. The results showed that： the yield strength and tensile strength of Q500qENH weathering steel significantly increased at low temperatures， while the fatigue crack propagation rate significantly decreased； the fatigue life test result fit well with the simulation result， indicating the effectiveness of the test data； the life of vulnerable welded joints decreased with the increase of temperature， the fatigue performance of the top plate weld toe joints was poor， and the longitudinal rib butt joints had a longer fatigue life； low average temperature can effectively delay the crack propagation of the top plate weld toe of the bridge deck and improve the fatigue life.
To accurately evaluate the fatigue performance of welded joints in weathering steel bridge decks under the coupling effect of low-temperature environment and multiple vehicle-borne factors， this paper conducted tensile tests and fatigue crack propagation tests on Q500qENH weathering steel specimens under multi-temperature conditions. To verify the test results， corresponding finite element simulations of fatigue crack propagation in the specimens were performed. An orthotropic steel bridge deck finite element model was established to conduct a comparative analysis of the fatigue crack propagation behavior of vulnerable welded joints under multiple constant temperature conditions. Based on this model， the fatigue life prediction of vulnerable welded joints under variable temperature conditions was carried out. The results showed that： the yield strength and tensile strength of Q500qENH weathering steel significantly increased at low temperatures， while the fatigue crack propagation rate significantly decreased； the fatigue life test result fit well with the simulation result， indicating the effectiveness of the test data； the life of vulnerable welded joints decreased with the increase of temperature， the fatigue performance of the top plate weld toe joints was poor， and the longitudinal rib butt joints had a longer fatigue life； low average temperature can effectively delay the crack propagation of the top plate weld toe of the bridge deck and improve the fatigue life.
2025, 55(9): 95-103.
doi: 10.3724/j.gyjzG23070301
Abstract:
Promoting the industrial construction of rural dwellings is an important part of rural development at the present stage， and standardization is the foundation of architectural industrialization. This study takes residential buildings in the Loess Plateau as its object， starts from the "frame" system inherent in traditional dwelling spaces， translates it into a "modular" mode， and uses light-gauge steel structures to standardize the spatial design of residential buildings in this region. Adopting a "steel-for-wood" approach， it explores a regional development mode for industrial construction and proposes a scientifically feasible spatial standardization system suitable for the region.
Promoting the industrial construction of rural dwellings is an important part of rural development at the present stage， and standardization is the foundation of architectural industrialization. This study takes residential buildings in the Loess Plateau as its object， starts from the "frame" system inherent in traditional dwelling spaces， translates it into a "modular" mode， and uses light-gauge steel structures to standardize the spatial design of residential buildings in this region. Adopting a "steel-for-wood" approach， it explores a regional development mode for industrial construction and proposes a scientifically feasible spatial standardization system suitable for the region.
2025, 55(9): 104-114.
doi: 10.3724/j.gyjzG23072603
Abstract:
The vitality of rural tourism destinations is an important factor in the revitalization of traditional village tourism. The widespread application of multi-source data and machine learning analysis systems has broadened the research perspective of rural built-up environments. However， in the current research on the factors affecting rural spatial vitality， there is a lack of more detailed exploration of the causes of human subjective perception factors. This study took Beigang Village， Pingtan County， as the research object. Firstly， the population thermal data， POI （Point of Interest） data， and street scene shooting data were classified and organized. Secondly， the semantic segmentation method and public perception score were used to obtain the proportion and scoring data of landscape elements. Finally， XGBoost （eXtreme Gradient Boosting） method was used to construct the model， and the contribution of different elements was explained through the SHAP （Shapley Additive Explanations） method. The experimental results showed that： 1） Blue vision rate， width， paving degree， and dirtiness are the four most influential indicators， and have a certain non-linear relationship， reflecting the important significance of characteristic landscape construction for enhancing rural spatial vitality. 2） Many indicators， such as green vision rate and blue vision rate， exhibit a distribution pattern of jumping aggregation， indicating weak continuity in landscape planning and design. The conclusion indicates that the fault characterization of different landscape elements and the interaction mechanism between landscape elements and spatial vitality have expanded the application methods of multi-source data and detailed landscape data in meso and micro scale spaces， providing reference for rural tourism destination planning and landscape design.
The vitality of rural tourism destinations is an important factor in the revitalization of traditional village tourism. The widespread application of multi-source data and machine learning analysis systems has broadened the research perspective of rural built-up environments. However， in the current research on the factors affecting rural spatial vitality， there is a lack of more detailed exploration of the causes of human subjective perception factors. This study took Beigang Village， Pingtan County， as the research object. Firstly， the population thermal data， POI （Point of Interest） data， and street scene shooting data were classified and organized. Secondly， the semantic segmentation method and public perception score were used to obtain the proportion and scoring data of landscape elements. Finally， XGBoost （eXtreme Gradient Boosting） method was used to construct the model， and the contribution of different elements was explained through the SHAP （Shapley Additive Explanations） method. The experimental results showed that： 1） Blue vision rate， width， paving degree， and dirtiness are the four most influential indicators， and have a certain non-linear relationship， reflecting the important significance of characteristic landscape construction for enhancing rural spatial vitality. 2） Many indicators， such as green vision rate and blue vision rate， exhibit a distribution pattern of jumping aggregation， indicating weak continuity in landscape planning and design. The conclusion indicates that the fault characterization of different landscape elements and the interaction mechanism between landscape elements and spatial vitality have expanded the application methods of multi-source data and detailed landscape data in meso and micro scale spaces， providing reference for rural tourism destination planning and landscape design.
2025, 55(9): 115-123.
doi: 10.3724/j.gyjzG24042213
Abstract:
As an important part of historical and cultural heritage， the delineation of construction control zones for industrial heritage units is mostly based on the methods used for ancient buildings. However， this method often fails to account for the relevance and continuity of industrial activities， as well as their unique specificities. Furthermore， there is a lack of unified understanding and effective control over the indirect influence zones in the broader areas beyond the tightly-constructed control zones. Therefore， based on theories and practices related to the construction control zones of historical and cultural heritage， this paper employed field theory and incorporated relevant research to analyze the relational space and hierarchical field effects of industrial heritage. On the premise of constructing the concepts of strong， balanced， and weak fields， emphasizing the related activities and visual impacts， and highlighting the relationship between industrial heritage and the overall development level of the small city， this paper proposed a "2+2" classification concept and method for delineating four types of construction control zones. Additionally， the method was empirically applied to Xihai Town， a city known for its red ideals and beliefs and abundant industrial heritage.
As an important part of historical and cultural heritage， the delineation of construction control zones for industrial heritage units is mostly based on the methods used for ancient buildings. However， this method often fails to account for the relevance and continuity of industrial activities， as well as their unique specificities. Furthermore， there is a lack of unified understanding and effective control over the indirect influence zones in the broader areas beyond the tightly-constructed control zones. Therefore， based on theories and practices related to the construction control zones of historical and cultural heritage， this paper employed field theory and incorporated relevant research to analyze the relational space and hierarchical field effects of industrial heritage. On the premise of constructing the concepts of strong， balanced， and weak fields， emphasizing the related activities and visual impacts， and highlighting the relationship between industrial heritage and the overall development level of the small city， this paper proposed a "2+2" classification concept and method for delineating four types of construction control zones. Additionally， the method was empirically applied to Xihai Town， a city known for its red ideals and beliefs and abundant industrial heritage.
2025, 55(9): 124-133.
doi: 10.3724/j.gyjzG23051615
Abstract:
The concept of "renewal" promotes the integration of aging-adapted infrastructure with gradual， diversified spatial improvement methods. In the context of community all-age activity circles， aging-adapted renewal emphasizes the continuation and upgrading of frequently visited and interactive active spaces. Under the influence of social networks， outdoor all-age activity circles can be categorized into three types： close-to-home， neighborhood-connected， and expanded-neighborhood interest-based. Based on field research， this study analyzed the preferences of elderly individuals across these circles regarding 18 spatial elements， subsequently proposing targeted aging-adapted renewal design strategies.
The concept of "renewal" promotes the integration of aging-adapted infrastructure with gradual， diversified spatial improvement methods. In the context of community all-age activity circles， aging-adapted renewal emphasizes the continuation and upgrading of frequently visited and interactive active spaces. Under the influence of social networks， outdoor all-age activity circles can be categorized into three types： close-to-home， neighborhood-connected， and expanded-neighborhood interest-based. Based on field research， this study analyzed the preferences of elderly individuals across these circles regarding 18 spatial elements， subsequently proposing targeted aging-adapted renewal design strategies.
Research on Static Performance of an Aircraft Hangar Grid Roof Under Different Supporting Conditions
2025, 55(9): 134-140.
doi: 10.3724/j.gyjzG23072713
Abstract:
In order to explore the influence of different supporting conditions on the static performance of the three-sided supporting grid roof unique to hangar buildings， the vertical displacement， static internal force of members， reaction force of bearing joints， and horizontal displacement were systematically analyzed for an aircraft hangar grid roof under three models： a hinged support model （Model 1）， an elastic support model （Model 2）， and an overall analysis model （Model 3）. The results showed that， compared with the other two models， the nodal displacements， member internal forces， and bearing reaction forces in Model 1 were more discrete. The static internal forces in the upper chords of the roof were generally large， followed by those in the lower chords， while the web members exhibited smaller static internal forces. The numerical values and trends of vertical nodal displacements， static internal forces of members， and nodal reaction forces in the X and Y directions at corresponding positions of Model 2 and Model 3 were very close. In practice， the horizontal stiffness of Model 3 was greater than that of Model 2， with a significant difference in Y-direction stiffness near the opening edge. The hinged support method for the static design of the hangar roof structure posed safety risks， whereas the simplified method for elastic supports exhibited better practicality.
In order to explore the influence of different supporting conditions on the static performance of the three-sided supporting grid roof unique to hangar buildings， the vertical displacement， static internal force of members， reaction force of bearing joints， and horizontal displacement were systematically analyzed for an aircraft hangar grid roof under three models： a hinged support model （Model 1）， an elastic support model （Model 2）， and an overall analysis model （Model 3）. The results showed that， compared with the other two models， the nodal displacements， member internal forces， and bearing reaction forces in Model 1 were more discrete. The static internal forces in the upper chords of the roof were generally large， followed by those in the lower chords， while the web members exhibited smaller static internal forces. The numerical values and trends of vertical nodal displacements， static internal forces of members， and nodal reaction forces in the X and Y directions at corresponding positions of Model 2 and Model 3 were very close. In practice， the horizontal stiffness of Model 3 was greater than that of Model 2， with a significant difference in Y-direction stiffness near the opening edge. The hinged support method for the static design of the hangar roof structure posed safety risks， whereas the simplified method for elastic supports exhibited better practicality.
2025, 55(9): 141-151.
doi: 10.3724/j.gyjzG23070305
Abstract:
To address the issue of brittle fracture of welding joints in special center-supported steel frame systems and achieve multi-staged energy dissipation， a buckling-resistant bracing system with a weakened ductile casting was introduced into the special center-supported steel frame structure. Twelve structural models with different parameters were established using ABAQUS software for low-cycle reciprocating loading. The results showed that the energy dissipation performance of the structure with the new bracing system was excellent， and the non-elastic deformation of the structure was mainly concentrated in the energy dissipation section of the weakening-type ductile casting， which effectively alleviated the stress concentration problem in the welding joint zone. Under the constraint of the sleeve， the length of the energy dissipation section of the weakening-type ductile casting had no significant effect on the energy dissipation performance， ultimate bearing capacity， and stiffness of the model. Combining the ultimate bearing capacity analysis， the seismic performance of the structural system was optimal when the axial force super-strong coefficient was controlled between 0.92 and 1.10. Based on the finite element analysis results， the elastic stiffness and yield bearing capacity of the structure were derived， and the error between the theoretical results and the numerical simulation results was within 10%， indicating satisfactory predictability.
To address the issue of brittle fracture of welding joints in special center-supported steel frame systems and achieve multi-staged energy dissipation， a buckling-resistant bracing system with a weakened ductile casting was introduced into the special center-supported steel frame structure. Twelve structural models with different parameters were established using ABAQUS software for low-cycle reciprocating loading. The results showed that the energy dissipation performance of the structure with the new bracing system was excellent， and the non-elastic deformation of the structure was mainly concentrated in the energy dissipation section of the weakening-type ductile casting， which effectively alleviated the stress concentration problem in the welding joint zone. Under the constraint of the sleeve， the length of the energy dissipation section of the weakening-type ductile casting had no significant effect on the energy dissipation performance， ultimate bearing capacity， and stiffness of the model. Combining the ultimate bearing capacity analysis， the seismic performance of the structural system was optimal when the axial force super-strong coefficient was controlled between 0.92 and 1.10. Based on the finite element analysis results， the elastic stiffness and yield bearing capacity of the structure were derived， and the error between the theoretical results and the numerical simulation results was within 10%， indicating satisfactory predictability.
2025, 55(9): 152-158.
doi: 10.3724/j.gyjzG23072409
Abstract:
The seismic performance analysis of a steel braced frame focuses on accurately simulating the strong nonlinear behavior of steel braces， including buckling and fracture. In OpenSEES software， a fiber beam-column element model with initial imperfection was used to simulate the buckling behavior of conventional steel braces （CBs）， while the Coffin-Manson relationship was employed to describe the low-cycle fatigue properties of both buckling-restrained braces （BRBs） and CBs.The hysteretic simulation results of the braces verified the method's feasibility. Based on this simulation approach， the seismic performance of buckling-restrained braced frames （BRBFs） and conventional braced frames （CBFs） was comparatively analyzed. Both systems were designed for the same building conditions following code requirements.The results showed that the area demand of the BRB was less than that of the CB， and the pushover curve of the CBF had a larger initial stiffness， while the buckling of the CB led to a sudden decrease in the structural bearing capacity.The structural responses of the BRBF were lower than those of the CBF under rare earthquakes. Under repeated strong earthquakes， some conventional braces （CBs） fractured， while all buckling-restrained braces （BRBs） remained intact.Compared to structural responses under rare earthquakes， both structural systems exhibited increased responses under repeated strong earthquakes， with conventional braced steel frames demonstrating greater response amplification than buckling-restrained braced frames.
The seismic performance analysis of a steel braced frame focuses on accurately simulating the strong nonlinear behavior of steel braces， including buckling and fracture. In OpenSEES software， a fiber beam-column element model with initial imperfection was used to simulate the buckling behavior of conventional steel braces （CBs）， while the Coffin-Manson relationship was employed to describe the low-cycle fatigue properties of both buckling-restrained braces （BRBs） and CBs.The hysteretic simulation results of the braces verified the method's feasibility. Based on this simulation approach， the seismic performance of buckling-restrained braced frames （BRBFs） and conventional braced frames （CBFs） was comparatively analyzed. Both systems were designed for the same building conditions following code requirements.The results showed that the area demand of the BRB was less than that of the CB， and the pushover curve of the CBF had a larger initial stiffness， while the buckling of the CB led to a sudden decrease in the structural bearing capacity.The structural responses of the BRBF were lower than those of the CBF under rare earthquakes. Under repeated strong earthquakes， some conventional braces （CBs） fractured， while all buckling-restrained braces （BRBs） remained intact.Compared to structural responses under rare earthquakes， both structural systems exhibited increased responses under repeated strong earthquakes， with conventional braced steel frames demonstrating greater response amplification than buckling-restrained braced frames.
2025, 55(9): 159-167.
doi: 10.3724/j.gyjzG22110203
Abstract:
Due to the different spatial layout of the building， there are irregular-shaped panel zones in the steel frame for unequal height of the left and right beams. In order to study the effect of shear deformation in these irregular-shaped panel zones on the seismic fragility of steel frames， a mathematical model for evaluating the shear deformation performance of such irregular-shaped panel zones was developed. This model was based on numerical simulations of 40 sets of irregular-shaped panel zones， combined with existing test data. Afterwards， OpenSEES was used to analyze the seismic fragility of the steel frame mode， considering the shear deformation in panel zones. This study examined the influence of several key parameters on seismic performance： the beam depth ratio， span ratio， column-beam strength ratio， and beam-column's linear stiffness ratio. The results showed that varying the depth ratio of beams had a significant effect on the seismic fragility of the steel frame under ground motions of the same intensity. With the depth ratio of the beams ranging from 0.571 to 1.000， a smaller ratio resulted in better seismic performance of the structure.When reaching the four limit states， the failure probability of the steel frame was the lowest at a beam depth ratio of 0.571， indicating the optimal seismic performance of the structure. Variations in span ratios within the range of 0.871 to 1.086 had a relatively limited effect on the vulnerability of the structure， suggesting that this range can be considered a stable safety interval.
Due to the different spatial layout of the building， there are irregular-shaped panel zones in the steel frame for unequal height of the left and right beams. In order to study the effect of shear deformation in these irregular-shaped panel zones on the seismic fragility of steel frames， a mathematical model for evaluating the shear deformation performance of such irregular-shaped panel zones was developed. This model was based on numerical simulations of 40 sets of irregular-shaped panel zones， combined with existing test data. Afterwards， OpenSEES was used to analyze the seismic fragility of the steel frame mode， considering the shear deformation in panel zones. This study examined the influence of several key parameters on seismic performance： the beam depth ratio， span ratio， column-beam strength ratio， and beam-column's linear stiffness ratio. The results showed that varying the depth ratio of beams had a significant effect on the seismic fragility of the steel frame under ground motions of the same intensity. With the depth ratio of the beams ranging from 0.571 to 1.000， a smaller ratio resulted in better seismic performance of the structure.When reaching the four limit states， the failure probability of the steel frame was the lowest at a beam depth ratio of 0.571， indicating the optimal seismic performance of the structure. Variations in span ratios within the range of 0.871 to 1.086 had a relatively limited effect on the vulnerability of the structure， suggesting that this range can be considered a stable safety interval.
2025, 55(9): 168-175.
doi: 10.3724/j.gyjzG22122806
Abstract:
To evaluate the influence of double-beam composite action on the lateral resistance of modular steel buildings， full-scale tests， numerical simulations， and theoretical analyses were conducted on four modular steel sub-frame specimens with composite double beams. The lateral resistance was analyzed， the load transfer mechanism was verified， and finally the lateral force-resisting mechanism was revealed with the development of an initial lateral stiffness model. The results showed that after the installation of high-strength bolts，the lateral bearing capacity and initial lateral stiffness increased by approximately 15% and 19%， respectively. The mechanistic analysis indicated that the composite bolted double-beam system optimized the lateral load transfer path in modular buildings， enhancing the mechanical coupling between upper and lower modules. Additionally， the composite bending action of the double beams improved the equivalent stiffness of double-beam structures， thereby effectively enhancing the overall lateral resistance. Based on the theoretical formula for equivalent bending stiffness of double-beam structures， a mechanical model for the initial lateral stiffness of modular steel sub-frames was proposed. The calculated results from the model agreed well with both experimental and numerical results.
To evaluate the influence of double-beam composite action on the lateral resistance of modular steel buildings， full-scale tests， numerical simulations， and theoretical analyses were conducted on four modular steel sub-frame specimens with composite double beams. The lateral resistance was analyzed， the load transfer mechanism was verified， and finally the lateral force-resisting mechanism was revealed with the development of an initial lateral stiffness model. The results showed that after the installation of high-strength bolts，the lateral bearing capacity and initial lateral stiffness increased by approximately 15% and 19%， respectively. The mechanistic analysis indicated that the composite bolted double-beam system optimized the lateral load transfer path in modular buildings， enhancing the mechanical coupling between upper and lower modules. Additionally， the composite bending action of the double beams improved the equivalent stiffness of double-beam structures， thereby effectively enhancing the overall lateral resistance. Based on the theoretical formula for equivalent bending stiffness of double-beam structures， a mechanical model for the initial lateral stiffness of modular steel sub-frames was proposed. The calculated results from the model agreed well with both experimental and numerical results.
2025, 55(9): 176-184.
doi: 10.3724/j.gyjzG22112307
Abstract:
In order to explore the hysteretic constitutive relationship of TA2/Q235 titanium-steel clad plates under cyclic loading， a total of 28 titanium-steel clad plate specimens under various loading protocols were tested. The monotonic behavior， hysteretic behavior， and fracture morphology of the specimens were obtained. The hysteretic curves of the specimens subjected to cyclic loading were plump without obvious pinching effects， demonstrating a mixed hardening characteristic combining isotropic hardening and kinematic hardening. Microvoid coalescence fracture， a typical mode of ductile fracture， was observed from the fracture morphology. The skeleton curves of titanium-steel clad plates were fitted using the Ramberg-Osgood equation， while the Chaboche plastic constitutive model was used to characterize the hysteretic behavior of the specimens. Based on the experimental results， the material parameters for both the skeleton curve model and hysteretic constitutive model were calibrated. The effects of the cladding ratio were examined using the calibrated hysteretic constitutive model. The results showed that the isotropic hardening effect of the titanium-steel clad plates became more significant with a decreasing cladding ratio， while the kinematic hardening characteristic remained unchanged. Using the ABAQUS finite element software， a numerical simulation of the cyclic loading test process was conducted. The simulation results agreed well with the experimental hysteresis curves， indicating that the calibrated parameters accurately predicted the response of titanium-steel clad plates under cyclic loading.
In order to explore the hysteretic constitutive relationship of TA2/Q235 titanium-steel clad plates under cyclic loading， a total of 28 titanium-steel clad plate specimens under various loading protocols were tested. The monotonic behavior， hysteretic behavior， and fracture morphology of the specimens were obtained. The hysteretic curves of the specimens subjected to cyclic loading were plump without obvious pinching effects， demonstrating a mixed hardening characteristic combining isotropic hardening and kinematic hardening. Microvoid coalescence fracture， a typical mode of ductile fracture， was observed from the fracture morphology. The skeleton curves of titanium-steel clad plates were fitted using the Ramberg-Osgood equation， while the Chaboche plastic constitutive model was used to characterize the hysteretic behavior of the specimens. Based on the experimental results， the material parameters for both the skeleton curve model and hysteretic constitutive model were calibrated. The effects of the cladding ratio were examined using the calibrated hysteretic constitutive model. The results showed that the isotropic hardening effect of the titanium-steel clad plates became more significant with a decreasing cladding ratio， while the kinematic hardening characteristic remained unchanged. Using the ABAQUS finite element software， a numerical simulation of the cyclic loading test process was conducted. The simulation results agreed well with the experimental hysteresis curves， indicating that the calibrated parameters accurately predicted the response of titanium-steel clad plates under cyclic loading.
2025, 55(9): 185-192.
doi: 10.3724/j.gyjzG22122003
Abstract:
To study the effects of the roughness of the composite beam joint surface and the position of the joint surface on the shear performance of the composite beam， shear tests were conducted on five composite beam specimens and one monolithic beam specimen. The failure characteristics， damage evolution process， load-deflection curve， bearing capacity， and load-longitudinal strain curve of each specimen were compared and analyzed. The test results showed that the roughness of the joint surface had little influence on the initial crack development of composite beam specimens but a significant influence on the appearance and development of joint surface cracks. The coarser joint surface led to shorter misaligned cracks， less damage， and a higher peak load in the composite beam specimens. When the joint surface was closer to the compression zone， it led to a smaller cracking displacement and lower cracking load at the joint surface， as well as longer misaligned cracks. These factors significantly influenced the integrity of the specimens， and the peak bearing capacity of the specimens decreased significantly. The shear bearing capacity of the composite beam specimens with rough treatment of the joint surface was calculated according to the current Chinese and American codes. The calculated shear bearing capacity for the composite beam specimens with rough treatment was relatively conservative. However， when the construction state of the composite beam joint surface was poor—such as when the joint surface was smooth or lacked rough treatment—the design could not be carried out in accordance with the code， as the calculation results would be unsafe.
To study the effects of the roughness of the composite beam joint surface and the position of the joint surface on the shear performance of the composite beam， shear tests were conducted on five composite beam specimens and one monolithic beam specimen. The failure characteristics， damage evolution process， load-deflection curve， bearing capacity， and load-longitudinal strain curve of each specimen were compared and analyzed. The test results showed that the roughness of the joint surface had little influence on the initial crack development of composite beam specimens but a significant influence on the appearance and development of joint surface cracks. The coarser joint surface led to shorter misaligned cracks， less damage， and a higher peak load in the composite beam specimens. When the joint surface was closer to the compression zone， it led to a smaller cracking displacement and lower cracking load at the joint surface， as well as longer misaligned cracks. These factors significantly influenced the integrity of the specimens， and the peak bearing capacity of the specimens decreased significantly. The shear bearing capacity of the composite beam specimens with rough treatment of the joint surface was calculated according to the current Chinese and American codes. The calculated shear bearing capacity for the composite beam specimens with rough treatment was relatively conservative. However， when the construction state of the composite beam joint surface was poor—such as when the joint surface was smooth or lacked rough treatment—the design could not be carried out in accordance with the code， as the calculation results would be unsafe.
2025, 55(9): 193-199.
doi: 10.3724/j.gyjzG24070301
Abstract:
Experimental investigations were conducted on three partially-encased composite steel-concrete column specimens with cross-shaped sections （short for cross-shaped PEC columns） under constant vertical load and cyclic horizontal loading. The specimens consisted of one PEC column with a main steel component （MSC） of solid web steel （short for SWS cross-shaped PEC column） and two PEC columns with MSCs of honeycomb steel （short for HS cross-shaped PEC columns） having different axial compression ratios. The effects of the MSC web opening and the axial compression ratios on the seismic performance of cross-shaped PEC columns were investigated. The results showed that the failure characteristics of the PEC columns were concrete crushing accompanied by elastic-plastic buckling of the compression flange， ultimately leading to a compression-bending failure mode. The load-displacement hysteresis curves of the column specimens were full， and the hysteresis loops under different cycle numbers at the same loading stage （same amplitude） were nearly identical， indicating that the PEC columns exhibited good energy dissipation capacity and bearing capacity stability.The bearing capacity， elastic lateral stiffness， ductility， and energy dissipation capacity of the SWS cross-shaped PEC column were higher than those of the HS cross-shaped PEC columns under the same axial compression force. With the increase in axial compression ratio， the bearing capacity and lateral stiffness of HS cross-shaped PEC columns increased， but the ductility and deformation capacity decreased significantly， and the energy dissipation capacity also decreased. The full-section plasticity theory could effectively predict the bearing capacity of the cross-shaped PEC columns under uniaxial bending.
Experimental investigations were conducted on three partially-encased composite steel-concrete column specimens with cross-shaped sections （short for cross-shaped PEC columns） under constant vertical load and cyclic horizontal loading. The specimens consisted of one PEC column with a main steel component （MSC） of solid web steel （short for SWS cross-shaped PEC column） and two PEC columns with MSCs of honeycomb steel （short for HS cross-shaped PEC columns） having different axial compression ratios. The effects of the MSC web opening and the axial compression ratios on the seismic performance of cross-shaped PEC columns were investigated. The results showed that the failure characteristics of the PEC columns were concrete crushing accompanied by elastic-plastic buckling of the compression flange， ultimately leading to a compression-bending failure mode. The load-displacement hysteresis curves of the column specimens were full， and the hysteresis loops under different cycle numbers at the same loading stage （same amplitude） were nearly identical， indicating that the PEC columns exhibited good energy dissipation capacity and bearing capacity stability.The bearing capacity， elastic lateral stiffness， ductility， and energy dissipation capacity of the SWS cross-shaped PEC column were higher than those of the HS cross-shaped PEC columns under the same axial compression force. With the increase in axial compression ratio， the bearing capacity and lateral stiffness of HS cross-shaped PEC columns increased， but the ductility and deformation capacity decreased significantly， and the energy dissipation capacity also decreased. The full-section plasticity theory could effectively predict the bearing capacity of the cross-shaped PEC columns under uniaxial bending.
2025, 55(9): 200-208.
doi: 10.3724/j.gyjzG23071905
Abstract:
In this paper， 12 ordinary aluminum tube and stiffened aluminum tube stub columns were tested under axial compression at low temperature to study their performance indicators， such as axial compression failure mode， load displacement curve， load strain curve， strength， stiffness and ductility coefficient under low temperature， and analyze the impact of low temperature level （20，-30，-60 ℃） and aluminum tube inner wall stiffening on axial compression performance of aluminum tube stub columns. The results showed that the failure mode of the ordinary aluminum tubular short column was elephant foot buckling at the end， while the failure mode of a stiffened aluminum tubular short column was local buckling at the waist of the aluminum tube and failure due to instability of the stiffening rib. The load displacement curves of aluminum tubular short columns at low temperatures were similar to those at normal temperatures， including elastic， nonlinear and degenerate sections. Low temperature improved the strength and weakens the ductility of aluminum alloy short columns， but had no significant effect on the initial stiffness. The stiffening of the inner wall of the aluminum tube had a significant effect on the load displacement curve， which was mainly reflected in the improvement of strength and ductility. Finally， based on Eurocode 3“Design of Steel Structures-Part 1.4： General Rules-Supplementary Rules for Stainless Steels”， American code AISC 360-22 “Specification for Structural Steel Buildings”and Chinese code GB 50017—2017“Standard for Steel Structure Design”， the calculation methods of compression bearing capacity of aluminum tubular short columns were compared and analyzed. The results showed that the calculated values of the bearing capacity design formulas of Eurocode 3 and Chinese code were too large and tend to be unsafe， while the American code was relatively conservative and most close to the test values.
In this paper， 12 ordinary aluminum tube and stiffened aluminum tube stub columns were tested under axial compression at low temperature to study their performance indicators， such as axial compression failure mode， load displacement curve， load strain curve， strength， stiffness and ductility coefficient under low temperature， and analyze the impact of low temperature level （20，-30，-60 ℃） and aluminum tube inner wall stiffening on axial compression performance of aluminum tube stub columns. The results showed that the failure mode of the ordinary aluminum tubular short column was elephant foot buckling at the end， while the failure mode of a stiffened aluminum tubular short column was local buckling at the waist of the aluminum tube and failure due to instability of the stiffening rib. The load displacement curves of aluminum tubular short columns at low temperatures were similar to those at normal temperatures， including elastic， nonlinear and degenerate sections. Low temperature improved the strength and weakens the ductility of aluminum alloy short columns， but had no significant effect on the initial stiffness. The stiffening of the inner wall of the aluminum tube had a significant effect on the load displacement curve， which was mainly reflected in the improvement of strength and ductility. Finally， based on Eurocode 3“Design of Steel Structures-Part 1.4： General Rules-Supplementary Rules for Stainless Steels”， American code AISC 360-22 “Specification for Structural Steel Buildings”and Chinese code GB 50017—2017“Standard for Steel Structure Design”， the calculation methods of compression bearing capacity of aluminum tubular short columns were compared and analyzed. The results showed that the calculated values of the bearing capacity design formulas of Eurocode 3 and Chinese code were too large and tend to be unsafe， while the American code was relatively conservative and most close to the test values.
2025, 55(9): 209-217.
doi: 10.3724/j.gyjzG22072202
Abstract:
As a major international event， the Beijing Winter Olympics used a large number of scaffolding for the construction of temporary stands or stages. The temporary stand support frame with plug-in joints was taken as the research object. A 2×2 full-scale model was designed and manufactured， and unidirectional horizontal loading tests were conducted to investigate its slip modes， displacement response， and strain distribution under no load， 0.5 kN/m2， 2.0 kN/m2， and 3.5 kN/m2 conditions. The load-displacement curve was plotted to determine the structural slip load. For experimental comparison， wind loads corresponding to Level 10-12 wind forces in the competition zone were selected to verify the safety and stability of the frame structure in practical engineering applications. An 8×2 analytical model was established using SAP2000 to evaluate the mechanical properties indicators such as modal characteristics， anti-overturning stability， and stress ratios of the overall structure.The results showed that the frame structure exhibited excellent anti-slip stability， and most of the members remained in an elastic stress state during the test. Since the external load applied in the test was much higher than the actual wind load， the structural system possessed a large safety reserve. This study can provide technical support and reference for the practical application of plug-in scaffold support frames.
As a major international event， the Beijing Winter Olympics used a large number of scaffolding for the construction of temporary stands or stages. The temporary stand support frame with plug-in joints was taken as the research object. A 2×2 full-scale model was designed and manufactured， and unidirectional horizontal loading tests were conducted to investigate its slip modes， displacement response， and strain distribution under no load， 0.5 kN/m2， 2.0 kN/m2， and 3.5 kN/m2 conditions. The load-displacement curve was plotted to determine the structural slip load. For experimental comparison， wind loads corresponding to Level 10-12 wind forces in the competition zone were selected to verify the safety and stability of the frame structure in practical engineering applications. An 8×2 analytical model was established using SAP2000 to evaluate the mechanical properties indicators such as modal characteristics， anti-overturning stability， and stress ratios of the overall structure.The results showed that the frame structure exhibited excellent anti-slip stability， and most of the members remained in an elastic stress state during the test. Since the external load applied in the test was much higher than the actual wind load， the structural system possessed a large safety reserve. This study can provide technical support and reference for the practical application of plug-in scaffold support frames.
2025, 55(9): 218-225.
doi: 10.3724/j.gyjzG24090604
Abstract:
An accurate prediction of long-term embankment settlements is crucial for ensuring road safety and maintaining normal operations. Existing studies have employed inverse analysis of soil parameters based on monitoring data， subsequently updating settlement predictions using the inferred parameters. However， this method is hindered by high computational costs， limiting its widespread application in practical engineering. This paper proposed a long-term settlement prediction method for embankments based on sparse dictionary learning. A dictionary was constructed using finite element simulation results， and key atoms within the dictionary were identified and weighted through the analysis of settlement and horizontal displacement monitoring data. The long-term settlement was then predicted as a linear combination of a few significant atoms. The effectiveness of the proposed method was demonstrated using the Ballina trial embankment in Australia. Results indicated that the method successfully identified key atoms and their weights based on the dictionary derived from finite element analysis. By integrating sparse dictionary learning with multi-source monitoring data， this approach facilitated accurate long-term settlement predictions with low computational cost and high prediction accuracy.
An accurate prediction of long-term embankment settlements is crucial for ensuring road safety and maintaining normal operations. Existing studies have employed inverse analysis of soil parameters based on monitoring data， subsequently updating settlement predictions using the inferred parameters. However， this method is hindered by high computational costs， limiting its widespread application in practical engineering. This paper proposed a long-term settlement prediction method for embankments based on sparse dictionary learning. A dictionary was constructed using finite element simulation results， and key atoms within the dictionary were identified and weighted through the analysis of settlement and horizontal displacement monitoring data. The long-term settlement was then predicted as a linear combination of a few significant atoms. The effectiveness of the proposed method was demonstrated using the Ballina trial embankment in Australia. Results indicated that the method successfully identified key atoms and their weights based on the dictionary derived from finite element analysis. By integrating sparse dictionary learning with multi-source monitoring data， this approach facilitated accurate long-term settlement predictions with low computational cost and high prediction accuracy.
2025, 55(9): 226-237.
doi: 10.3724/j.gyjzG24072902
Abstract:
In China， the insufficient capabilities of construction equipment and traditional methods have long limited deep soil mixing （DSM） technology， presenting a bottleneck for constructing large diameter and deep mixing columns with sufficient mixing uniformity and consistent strength in the thick soft soils. The newly developed CS-DSM technology represents a significant improvement in drilling tool structure design， monitoring and control systems， and construction processes to resolve the drawbacks of the traditional DSM， namely poor uniformity， low compressive strength， drilling bit balling， surface spoiling， and waste on binder materials. Full-scale field comparison tests were conducted between CS-DSM columns and DDM columns. By combining core drilling and static load tests， the differences between the two methods were studied in terms of pile integrity， continuity， cement-soil strength， and bearing and deformation characteristics of a single column. The results indicated that the CS-DSM method offered more controllable and reliable construction quality comparing to the DDM method， reducing construction time by 44.4%， increasing single pile bearing capacity by 25%， and improving initial deformation stiffness by 97.0%. Based on field experiments conducted on an intercity transit project in Guangzhou， this paper showcased major aspects of CS-DSM technology including equipment and column installation process， monitoring and controlling technique， characterization of column uniformity， and UCS test data of core samples. The results indicated that the "one mixing cycle with slurry injected during the down stage" process reduced construction time by 40% compared to the traditional method. The frame-type mixing tool achieved an excellent degree of mixing for columns with adiameter of 1 m and a length of 46 m， and ensured a blade rotation number T of 600/m above， equivalent to the soilcrete per unit volume experiencing more than 40 passes of the mixing blade. The cement contents in the weakly and strongly reinforced zones were 8% and 18%~20%， respectively. The 21-day core sample strengths from both zones were minimum 4 times greater than the design strength. In conclusion， the CS-DSM method stably enhances mixing uniformity and develop high strength along the full column length. The field trial studies on this new technology can provide a reference for the promotion and application of the CS-DSM method.
In China， the insufficient capabilities of construction equipment and traditional methods have long limited deep soil mixing （DSM） technology， presenting a bottleneck for constructing large diameter and deep mixing columns with sufficient mixing uniformity and consistent strength in the thick soft soils. The newly developed CS-DSM technology represents a significant improvement in drilling tool structure design， monitoring and control systems， and construction processes to resolve the drawbacks of the traditional DSM， namely poor uniformity， low compressive strength， drilling bit balling， surface spoiling， and waste on binder materials. Full-scale field comparison tests were conducted between CS-DSM columns and DDM columns. By combining core drilling and static load tests， the differences between the two methods were studied in terms of pile integrity， continuity， cement-soil strength， and bearing and deformation characteristics of a single column. The results indicated that the CS-DSM method offered more controllable and reliable construction quality comparing to the DDM method， reducing construction time by 44.4%， increasing single pile bearing capacity by 25%， and improving initial deformation stiffness by 97.0%. Based on field experiments conducted on an intercity transit project in Guangzhou， this paper showcased major aspects of CS-DSM technology including equipment and column installation process， monitoring and controlling technique， characterization of column uniformity， and UCS test data of core samples. The results indicated that the "one mixing cycle with slurry injected during the down stage" process reduced construction time by 40% compared to the traditional method. The frame-type mixing tool achieved an excellent degree of mixing for columns with adiameter of 1 m and a length of 46 m， and ensured a blade rotation number T of 600/m above， equivalent to the soilcrete per unit volume experiencing more than 40 passes of the mixing blade. The cement contents in the weakly and strongly reinforced zones were 8% and 18%~20%， respectively. The 21-day core sample strengths from both zones were minimum 4 times greater than the design strength. In conclusion， the CS-DSM method stably enhances mixing uniformity and develop high strength along the full column length. The field trial studies on this new technology can provide a reference for the promotion and application of the CS-DSM method.
2025, 55(9): 238-246.
doi: 10.3724/j.gyjzG23081305
Abstract:
The lithologic foundation of nuclear power engineering in China is becoming increasingly scarce， and the development of inland nuclear power has become an inevitable trend. Improving the seismic ability of nuclear power structure on non-lithologic foundation has become one of the key topics in the construction of inland nuclear power plants. Based on the overall simulation analysis of soil-structure interaction with external fluctuations， this paper proposed the construction of an underground partition wall on the ground based on hydraulic curtain technology as an isolation measure， and discussed the effect of reducing the input of seismic wave energy to the superstructure. Firstly， based on the fine simulation of the external wave problem of soil-structure interaction， the effects of layout and material parameters of various underground isolation walls on the isolation effect were compared. Then， the seismic isolation measures are applied to the structural analysis of nuclear power plant， and the influence on the floor spectrum of nuclear power plant was studied. The research results show that the proposed inclined underground wall has good seismic isolation effect and can provide a new way to improve the seismic capability of important buildings such as nuclear island.
The lithologic foundation of nuclear power engineering in China is becoming increasingly scarce， and the development of inland nuclear power has become an inevitable trend. Improving the seismic ability of nuclear power structure on non-lithologic foundation has become one of the key topics in the construction of inland nuclear power plants. Based on the overall simulation analysis of soil-structure interaction with external fluctuations， this paper proposed the construction of an underground partition wall on the ground based on hydraulic curtain technology as an isolation measure， and discussed the effect of reducing the input of seismic wave energy to the superstructure. Firstly， based on the fine simulation of the external wave problem of soil-structure interaction， the effects of layout and material parameters of various underground isolation walls on the isolation effect were compared. Then， the seismic isolation measures are applied to the structural analysis of nuclear power plant， and the influence on the floor spectrum of nuclear power plant was studied. The research results show that the proposed inclined underground wall has good seismic isolation effect and can provide a new way to improve the seismic capability of important buildings such as nuclear island.
2025, 55(9): 247-254.
doi: 10.3724/j.gyjzG23081301
Abstract:
Occlusal pile supporting structure has been widely applied in deep foundation pit engineering in recent years， due to its advantages of less disturbance to the surrounding foundation， higher reliability and integrity， and less environmental impact. However， when the pit depth is large and the site is limited， the linear and circular supporting structures are difficult to meet the requirements. In this paper， the arch support structure of a large arch bridge in the Minjiang River was taken as the case. Based on the calculation theory of thin shell， a theoretical calculation model of arc-shaped occlusion pile was established and compared with the three-dimensional finite element calculation results and the field measured data. At the same time， the important parameters of the structure were changed to optimize the reasonable design parameters of the supporting structure. The results showed that the horizontal displacement of the arc-shaped occlusal pile supporting structure increased gradually from the corner point to the edge center. The maximum depth of a 50 m deep foundation pit with a side length was 18.6 m， and the maximum deformation was only 10 mm， which can effectively resist the deformation of soil and water pressure. The calculated deformation of the supporting structure based on the theoretical model of the shell was in good agreement with the measured values. The diameter of the occlusal pile was 1.0 m to 1.4 m， and the addition of the pile top tie beam could greatly improve the supporting ability. The effect of the arrangement of the side， middle and outside was far better than that of the corner position. This research has certain guiding significance for the optimization of the arc occlusal pile supporting structure.
Occlusal pile supporting structure has been widely applied in deep foundation pit engineering in recent years， due to its advantages of less disturbance to the surrounding foundation， higher reliability and integrity， and less environmental impact. However， when the pit depth is large and the site is limited， the linear and circular supporting structures are difficult to meet the requirements. In this paper， the arch support structure of a large arch bridge in the Minjiang River was taken as the case. Based on the calculation theory of thin shell， a theoretical calculation model of arc-shaped occlusion pile was established and compared with the three-dimensional finite element calculation results and the field measured data. At the same time， the important parameters of the structure were changed to optimize the reasonable design parameters of the supporting structure. The results showed that the horizontal displacement of the arc-shaped occlusal pile supporting structure increased gradually from the corner point to the edge center. The maximum depth of a 50 m deep foundation pit with a side length was 18.6 m， and the maximum deformation was only 10 mm， which can effectively resist the deformation of soil and water pressure. The calculated deformation of the supporting structure based on the theoretical model of the shell was in good agreement with the measured values. The diameter of the occlusal pile was 1.0 m to 1.4 m， and the addition of the pile top tie beam could greatly improve the supporting ability. The effect of the arrangement of the side， middle and outside was far better than that of the corner position. This research has certain guiding significance for the optimization of the arc occlusal pile supporting structure.
2025, 55(9): 255-265.
doi: 10.3724/j.gyjzG23011208
Abstract:
Since the 20th century， expansive soil instability accidents have frequently occurred worldwide， seriously threatening industrial and civil buildings， railways， highways， water conservancy， and other facilities. In order to mitigate geological hazards caused by shallow instability of expansive soil slopes， more effective prevention and control treatment should be carried out. On the basis of summarizing relevant domestic and international data， this paper investigated typical accident cases of expansive soil slopes. It focused on the research status of shallow instability testing， numerical simulation， and theoretical analysis of such slopes. The mechanism of shallow instability of expansive soil slopes were analyzed and summarized， along with the difficulties and hot issues in the current research. In addition， the research progress on control measures for shallow instability of expansive soil slopes was tracked and analyzed. This included a review of various mitigation techniques such as retaining and reinforcement structures， slope surface drainage systems， chemical improvement treatments， and vegetation protection engineering， as well as key factors influencing the effectiveness of these measures， including variations in moisture content， wet-dry cycles， slope gradient， and the development of soil cracks. Finally， future research directions were discussed and proposed based on the development trends and existing problems identified in current research.
Since the 20th century， expansive soil instability accidents have frequently occurred worldwide， seriously threatening industrial and civil buildings， railways， highways， water conservancy， and other facilities. In order to mitigate geological hazards caused by shallow instability of expansive soil slopes， more effective prevention and control treatment should be carried out. On the basis of summarizing relevant domestic and international data， this paper investigated typical accident cases of expansive soil slopes. It focused on the research status of shallow instability testing， numerical simulation， and theoretical analysis of such slopes. The mechanism of shallow instability of expansive soil slopes were analyzed and summarized， along with the difficulties and hot issues in the current research. In addition， the research progress on control measures for shallow instability of expansive soil slopes was tracked and analyzed. This included a review of various mitigation techniques such as retaining and reinforcement structures， slope surface drainage systems， chemical improvement treatments， and vegetation protection engineering， as well as key factors influencing the effectiveness of these measures， including variations in moisture content， wet-dry cycles， slope gradient， and the development of soil cracks. Finally， future research directions were discussed and proposed based on the development trends and existing problems identified in current research.
2025, 55(9): 266-275.
doi: 10.3724/j.gyjzG24101504
Abstract:
Current modular integrated construction （MiC） faces multiple challenges in various stages， including project design， module prefabrication， on-site installation， and post-construction operation and maintenance. These challenges include low design standardization， low factory production efficiency， long on-site module dwell time， and high post-operation maintenance costs. To maximize the benefits of MiC projects， this paper introduces the concept of integrated digital delivery （IDD）， a new management model， and investigates its application in MiC projects. The paper outlined the business processes of MiC projects， conducted an analysis of the applicability of the IDD model in MiC projects， based on the identified challenges. Furthermore， a tailored IDD application model for MiC projects was proposed. In addition， the paper examined the implementation of the IDD model in an affordable housing project and evaluated its maturity. Through theoretical analysis and practical case study， the paper demonstrated the feasibility and effectiveness of applying the IDD model to MiC projects， providing theoretical support and practical experience for similar future projects， and exploring a viable direction for the innovative development of industrialization in construction sector.
Current modular integrated construction （MiC） faces multiple challenges in various stages， including project design， module prefabrication， on-site installation， and post-construction operation and maintenance. These challenges include low design standardization， low factory production efficiency， long on-site module dwell time， and high post-operation maintenance costs. To maximize the benefits of MiC projects， this paper introduces the concept of integrated digital delivery （IDD）， a new management model， and investigates its application in MiC projects. The paper outlined the business processes of MiC projects， conducted an analysis of the applicability of the IDD model in MiC projects， based on the identified challenges. Furthermore， a tailored IDD application model for MiC projects was proposed. In addition， the paper examined the implementation of the IDD model in an affordable housing project and evaluated its maturity. Through theoretical analysis and practical case study， the paper demonstrated the feasibility and effectiveness of applying the IDD model to MiC projects， providing theoretical support and practical experience for similar future projects， and exploring a viable direction for the innovative development of industrialization in construction sector.
