Login
Register
E-alert
2021 Vol. 51, No. 4
Display Method:
2021, 51(4): 1-5,11.
doi: 10.13204/j.gyjzG20072006
Abstract:
Based on the ideas of modular design, the structural integration design strategy was put forward, morphological adaptability design strategy and functional compound design strategy for the enclosure system of tall and large space in north China were proposed. Taking the design process of the cable-tensioned box arched enclosure system as an example,how to realize the integration of supporting structure and enclosure interface by the synergistic action of cable and arch was discussed. Shape control and module partition replacement were used to meet the different functional requirements and construction conditions. Multi-layer cavity and integration structure were used to realize the functional compound of unit module. The above design strategies were applied to develop a modular enclosure system with the advantages of reasonable structure, simple structure, good adaptability, convenient installation and disassembly, repeated use, the sytem could adapt well to the climate and construction conditions of cold area, realize the green sustainable goals such as saving energy, manpower, construction period and so on.
Based on the ideas of modular design, the structural integration design strategy was put forward, morphological adaptability design strategy and functional compound design strategy for the enclosure system of tall and large space in north China were proposed. Taking the design process of the cable-tensioned box arched enclosure system as an example,how to realize the integration of supporting structure and enclosure interface by the synergistic action of cable and arch was discussed. Shape control and module partition replacement were used to meet the different functional requirements and construction conditions. Multi-layer cavity and integration structure were used to realize the functional compound of unit module. The above design strategies were applied to develop a modular enclosure system with the advantages of reasonable structure, simple structure, good adaptability, convenient installation and disassembly, repeated use, the sytem could adapt well to the climate and construction conditions of cold area, realize the green sustainable goals such as saving energy, manpower, construction period and so on.
2021, 51(4): 6-11.
doi: 10.13204/j.gyjzG20030609
Abstract:
Taking the design of Liaodong Bay cruise terminal passenger transport center as an example, the optimization method of large space building from based on climate adaptability in cold area was discussed. The topological model of building shape based on controllable parameters was studied, the energy consumption and predicted percentage of dissatisfied of large space building were taken as the optimization objectives, Ladybug and Honeybee tools were used under the platform of Grasshopper parameterization for simulation calculation, Galapagos tools were applied to genetic algorithm optimization to obtain the building shape with optimal evaluation indexes, which could improve the energy consumption and comfort degree of building. The above shape optimization methods of "simulation-calculation-selection" could provide a new idea for green design of large space buildings in cold area, and is of great significance to the development of green buildings in China.
Taking the design of Liaodong Bay cruise terminal passenger transport center as an example, the optimization method of large space building from based on climate adaptability in cold area was discussed. The topological model of building shape based on controllable parameters was studied, the energy consumption and predicted percentage of dissatisfied of large space building were taken as the optimization objectives, Ladybug and Honeybee tools were used under the platform of Grasshopper parameterization for simulation calculation, Galapagos tools were applied to genetic algorithm optimization to obtain the building shape with optimal evaluation indexes, which could improve the energy consumption and comfort degree of building. The above shape optimization methods of "simulation-calculation-selection" could provide a new idea for green design of large space buildings in cold area, and is of great significance to the development of green buildings in China.
2021, 51(4): 12-19.
doi: 10.13204/j.gyjzG20010703
Abstract:
After the Paris Agreement, low-carbon development has become an inevitable choice for countries around the world to cope with climate change. At present, most county economies in China are still in the middle stage of industrialization, and the potential of low-carbon development is huge and the demand is urgent. Therefore, compared with existing studies on low-carbon spatial planning at home and abroad, which mainly focus on urban areas, it is of more practical significance to carry out measurement analysis of carbon income and expenditure at the county level to promote national low-carbon development.The paper took Huantai County, an economically developed region, as the research object, on the basis of integrating multiple data sources, constructed a carbon balance zoning method, and calculated the energy consumption and emission, indirect carbon emission of household consumption and total carbon sink in 2016. The main conclusions are as follows:1) In 2016, the total carbon emission of Huantai County was 5.159 million tons, and the spatial pattern of carbon emission showed a dual center structure with Suo town, Guoli town and Tangshan town as the main center and Maqiao town as the sub center. 2) In 2016, the total amount of carbon sink in Huantai County was 234900 tons, and the spatial pattern of carbon sink showed the characteristics of "high in the northeast and low in the southwest" dominated by Jingjia town and Qifeng town. 3) Taking villages and towns as the basic spatial unit, Huantai County is divided into four types of carbon balance zones:carbon intensity control zone, low-carbon optimization zone, carbon balance zone and carbon sink function zone. On this basis, the paper put forward the county low-carbon spatial planning guidance countermeasures based on the optimization of carbon balance zoning, and explored the effective ways and methods for the county low-carbon development from the perspective of spatial layout.
After the Paris Agreement, low-carbon development has become an inevitable choice for countries around the world to cope with climate change. At present, most county economies in China are still in the middle stage of industrialization, and the potential of low-carbon development is huge and the demand is urgent. Therefore, compared with existing studies on low-carbon spatial planning at home and abroad, which mainly focus on urban areas, it is of more practical significance to carry out measurement analysis of carbon income and expenditure at the county level to promote national low-carbon development.The paper took Huantai County, an economically developed region, as the research object, on the basis of integrating multiple data sources, constructed a carbon balance zoning method, and calculated the energy consumption and emission, indirect carbon emission of household consumption and total carbon sink in 2016. The main conclusions are as follows:1) In 2016, the total carbon emission of Huantai County was 5.159 million tons, and the spatial pattern of carbon emission showed a dual center structure with Suo town, Guoli town and Tangshan town as the main center and Maqiao town as the sub center. 2) In 2016, the total amount of carbon sink in Huantai County was 234900 tons, and the spatial pattern of carbon sink showed the characteristics of "high in the northeast and low in the southwest" dominated by Jingjia town and Qifeng town. 3) Taking villages and towns as the basic spatial unit, Huantai County is divided into four types of carbon balance zones:carbon intensity control zone, low-carbon optimization zone, carbon balance zone and carbon sink function zone. On this basis, the paper put forward the county low-carbon spatial planning guidance countermeasures based on the optimization of carbon balance zoning, and explored the effective ways and methods for the county low-carbon development from the perspective of spatial layout.
2021, 51(4): 20-30,39.
doi: 10.13204/j.gyjzG20062704
Abstract:
Residential buildings are the types of buildings that people use for the longest time, and their energy consumption has a huge impact on the environment. Through the analysis of the current research and development at home and abroad, the paper summarized the index elements that affect residential carbon emissions.In addition, according to the contents of architectural features index elements in small towns, the low-carbon building index elements were filtered out to construct a low-carbon residential building element system guided by features.Taking Changxing County as an example, the paper summarized and sorted out the situation of urban residential buildings in Changxing County, analyzed the relationship between feature index and carbon emission under different elements of residential buildings in Changxing County, and proposed the low-carbon transformation strategy of urban residential buildings in Changxing County, Zhejiang Province.
Residential buildings are the types of buildings that people use for the longest time, and their energy consumption has a huge impact on the environment. Through the analysis of the current research and development at home and abroad, the paper summarized the index elements that affect residential carbon emissions.In addition, according to the contents of architectural features index elements in small towns, the low-carbon building index elements were filtered out to construct a low-carbon residential building element system guided by features.Taking Changxing County as an example, the paper summarized and sorted out the situation of urban residential buildings in Changxing County, analyzed the relationship between feature index and carbon emission under different elements of residential buildings in Changxing County, and proposed the low-carbon transformation strategy of urban residential buildings in Changxing County, Zhejiang Province.
2021, 51(4): 31-39.
doi: 10.13204/j.gyjzG20071005
Abstract:
The ingredients of equation for building shape coefficient contain length, width and height. Integrating the length and width, it forms the dimensions of first floor for the building. Simulating and analyzing by DesignBuilder, it was found that:the building plane-shaped coefficient and its first floor area were closely related with the energy consumption. The building energy consumption was directly proportional to the building plane-shaped coefficient, and inversely proportional to the first floor area. In addition, the equation of the building's plane-energy-consumption coefficient was formulated in this work. In order to research the distribution characteristics of plane-energy-consumption coefficient for the traditional dwellings in Sizhai village at the macro level, the distribution rules and statistical characteristics of dwellings with beeline-shaped plane, L-shaped plane, concave-shaped plane and shaped plane in each subregion were analyzed by G.E. respectively. Besides, utilizing the derived equation, the plane-energy-consumption coefficients for dwellings were computed for each subregion. Based on these statistical data, the conclusion was made that:the energy saving of building with rectangular-ambulatory-plane-shaped plane was the best, followed by cancave-shaped plane,L-shaped plane, beeline-shaped plane.
The ingredients of equation for building shape coefficient contain length, width and height. Integrating the length and width, it forms the dimensions of first floor for the building. Simulating and analyzing by DesignBuilder, it was found that:the building plane-shaped coefficient and its first floor area were closely related with the energy consumption. The building energy consumption was directly proportional to the building plane-shaped coefficient, and inversely proportional to the first floor area. In addition, the equation of the building's plane-energy-consumption coefficient was formulated in this work. In order to research the distribution characteristics of plane-energy-consumption coefficient for the traditional dwellings in Sizhai village at the macro level, the distribution rules and statistical characteristics of dwellings with beeline-shaped plane, L-shaped plane, concave-shaped plane and shaped plane in each subregion were analyzed by G.E. respectively. Besides, utilizing the derived equation, the plane-energy-consumption coefficients for dwellings were computed for each subregion. Based on these statistical data, the conclusion was made that:the energy saving of building with rectangular-ambulatory-plane-shaped plane was the best, followed by cancave-shaped plane,L-shaped plane, beeline-shaped plane.
2021, 51(4): 40-45,98.
doi: 10.13204/j.gyjzG20041109
Abstract:
The northern area of Yangtze-Huaihe region, Anhui Province, is located between the Huaihe River and the Yangtze River, close to the Huaihe River area, and in the northernmost region of Anhui subtropical zone. Based on local climate elements, residents have created traditional buildings that are comfortable in heat and cold, comfortable in ventilation and convenient in lighting. The methods of field survey and literature review were conducted to sum up the region's building layouts of traditional buildings, which were formed by the natural climate conditions, materials of enclosure systems and the characteristics of detailed construction. Through the Ecotect software, the climate adaptability of green construction strategy was simulated and analyzed, the ecological green construction wisdom for adjusting natural climatic resources was summed up, the new ideas of design and construction for the new era of building green sustainable development were proposed.
The northern area of Yangtze-Huaihe region, Anhui Province, is located between the Huaihe River and the Yangtze River, close to the Huaihe River area, and in the northernmost region of Anhui subtropical zone. Based on local climate elements, residents have created traditional buildings that are comfortable in heat and cold, comfortable in ventilation and convenient in lighting. The methods of field survey and literature review were conducted to sum up the region's building layouts of traditional buildings, which were formed by the natural climate conditions, materials of enclosure systems and the characteristics of detailed construction. Through the Ecotect software, the climate adaptability of green construction strategy was simulated and analyzed, the ecological green construction wisdom for adjusting natural climatic resources was summed up, the new ideas of design and construction for the new era of building green sustainable development were proposed.
2021, 51(4): 46-52,19.
doi: 10.13204/j.gyjzG20042002
Abstract:
The goal of energy conservation design and the requirement of building performance have been constantly improved, which has put forward higher requirements for energy conservation design. Moreover, the nonlinear relationship of multiple factors that affect the energy saving design undoubtedly increases the difficulty of further tapping the potential of energy saving design. Aiming at the optimization of passive design of high-rise residential buildings, the paper introduced radial basis function (RBF) neural network and orthogonal experiment design range method, and discussed the influence of passive design factors on energy consumption of high-rise residential buildings under different energy saving targets of 50%, 65% and 75%. In this research, analysis model was set up, and different factors, such as exterior wall, exterior window, roof, floor, interior wall, window-wall ratio, building orientation and number of floors were selected. Meanwhile, based on radial basis function (RBF) neural network, the heating and cooling energy consumption rapid response model was established to explore different energy-saving targets, the influencing factors on the heating and cooling energy consumption relations as well as the influence of the priority order, through the orthogonal experiment design process. The experiment showed that 65% and 75% of the energy saving targets could make the energy saving effect of the outer wall and the outer window of the high-rise residence more prominent. The improvement of energy saving target had changed the influence ranking of passive factors, and the increase in energy efficiency requirements from 50% to 75% reduced the impact of passive factors on energy efficiency from 3% to 0.5%.
The goal of energy conservation design and the requirement of building performance have been constantly improved, which has put forward higher requirements for energy conservation design. Moreover, the nonlinear relationship of multiple factors that affect the energy saving design undoubtedly increases the difficulty of further tapping the potential of energy saving design. Aiming at the optimization of passive design of high-rise residential buildings, the paper introduced radial basis function (RBF) neural network and orthogonal experiment design range method, and discussed the influence of passive design factors on energy consumption of high-rise residential buildings under different energy saving targets of 50%, 65% and 75%. In this research, analysis model was set up, and different factors, such as exterior wall, exterior window, roof, floor, interior wall, window-wall ratio, building orientation and number of floors were selected. Meanwhile, based on radial basis function (RBF) neural network, the heating and cooling energy consumption rapid response model was established to explore different energy-saving targets, the influencing factors on the heating and cooling energy consumption relations as well as the influence of the priority order, through the orthogonal experiment design process. The experiment showed that 65% and 75% of the energy saving targets could make the energy saving effect of the outer wall and the outer window of the high-rise residence more prominent. The improvement of energy saving target had changed the influence ranking of passive factors, and the increase in energy efficiency requirements from 50% to 75% reduced the impact of passive factors on energy efficiency from 3% to 0.5%.
2021, 51(4): 53-57.
doi: 10.13204/j.gyjzG21012105
Abstract:
The thermal parameters (thermal conductivity, thermal diffusion and specific heat capacity) of PF-AASCM were measured with hot-wire method at high temperatures (20 to 800℃). The thermal conductivity, thermal diffusion and specific heat capacity of PF-AASCM ranged from 0.8 to 3.7 W/(m·K), from 0.3 to 1.1 m2/s, and from 0.5 to 1.8 kJ/(kg·K), respectively. The thermal parameters showed a small peak at 200℃, which is indicated that a strong exothermic reaction happens. The thermal conductivity of PF-AASCM and concrete material was compared, and the analysis results showed that the thermal conductivity of PF-AASCM at 800℃ was basically the same as that of concrete. Its thermal diffusivity is higher, thermal conductivity and specific heat are relatively lower. It shows that PF-AASCM has good thermal diffusivity, but poor heat conduction and storage capacity, which indicates that PF-AASCM has heat insulation and heat storage capacity. The central temperature of the high-temperature specimen was measured, which was compared with the simulation results of finite element in the temperature field, the increase of the central temperature of the specimens is in good agreement.
The thermal parameters (thermal conductivity, thermal diffusion and specific heat capacity) of PF-AASCM were measured with hot-wire method at high temperatures (20 to 800℃). The thermal conductivity, thermal diffusion and specific heat capacity of PF-AASCM ranged from 0.8 to 3.7 W/(m·K), from 0.3 to 1.1 m2/s, and from 0.5 to 1.8 kJ/(kg·K), respectively. The thermal parameters showed a small peak at 200℃, which is indicated that a strong exothermic reaction happens. The thermal conductivity of PF-AASCM and concrete material was compared, and the analysis results showed that the thermal conductivity of PF-AASCM at 800℃ was basically the same as that of concrete. Its thermal diffusivity is higher, thermal conductivity and specific heat are relatively lower. It shows that PF-AASCM has good thermal diffusivity, but poor heat conduction and storage capacity, which indicates that PF-AASCM has heat insulation and heat storage capacity. The central temperature of the high-temperature specimen was measured, which was compared with the simulation results of finite element in the temperature field, the increase of the central temperature of the specimens is in good agreement.
2021, 51(4): 58-62,180.
doi: 10.13204/j.gyjzG21010708
Abstract:
The thermal parameters of the wall made of plant fiber-reinforced alkali-activated slag cementitious material were measured through the cold and hot box heat flow meter method. The wall size was selected with 780 mm×950 mm×190 mm, and the thermocouples and heat flow meters were used to measure the temperature and heat flow on both sides of the wall. Then, the thermal resistance 0.408 m2·K/W and heat transfer coefficient 1.792 W/(m2·K) of the wall were measured by the dynamic method and the static method, respectively. Finally, The thermal conductivity of the wall was calculated as 0.136 W/(m·K). Compared with the air thermal conductivity of 0.84 W/(m·K) and the thermal conductivity of concrete wall of 1.74 W/(m·K), the thermal conductivity of plant fiber-reinforced alkali-activated slag cementitious material was lower, which could prove that the fiber-reinforced alkali-activated slag cementitious material had good thermal insulation performance.
The thermal parameters of the wall made of plant fiber-reinforced alkali-activated slag cementitious material were measured through the cold and hot box heat flow meter method. The wall size was selected with 780 mm×950 mm×190 mm, and the thermocouples and heat flow meters were used to measure the temperature and heat flow on both sides of the wall. Then, the thermal resistance 0.408 m2·K/W and heat transfer coefficient 1.792 W/(m2·K) of the wall were measured by the dynamic method and the static method, respectively. Finally, The thermal conductivity of the wall was calculated as 0.136 W/(m·K). Compared with the air thermal conductivity of 0.84 W/(m·K) and the thermal conductivity of concrete wall of 1.74 W/(m·K), the thermal conductivity of plant fiber-reinforced alkali-activated slag cementitious material was lower, which could prove that the fiber-reinforced alkali-activated slag cementitious material had good thermal insulation performance.
2021, 51(4): 63-73,117.
doi: 10.13204/j.gyjzG20120405
Abstract:
Taking the dwellings in southern Anhui as the research objects, more than 50 newly-built dwellings were investigated and surveyed, and the spatial connection relations were abstracted from the perspective of spatial connection. Using the research method of spatial topological structure relations, the topological relations of dwelling plans and the characteristics of space types of topological nodes and three kinds of local structure including chains, trees, and ring were analyzed. Through calculation of the topological structure, the spatial topological relations of dwellings were divided into four connection types:courtyards, halls, corridors and composites. On the basis, the overall structure characteristics of hierarchic trees, hierarchic trees with multiple branches, and hierarchic trees with ring relations were combined with the functional attributes of spaces, revealing the isomorphic characteristics of residential lifestyles and spatial layouts. The research showed that the plan design of the dwellings had a certain general organization mode, which reflectd the regional characteristics of organization for dwelling plans. The research of topological structure for dwellings could provid standardized combination forms and design basis for the combination of dwelling plans in the background of industrialization.
Taking the dwellings in southern Anhui as the research objects, more than 50 newly-built dwellings were investigated and surveyed, and the spatial connection relations were abstracted from the perspective of spatial connection. Using the research method of spatial topological structure relations, the topological relations of dwelling plans and the characteristics of space types of topological nodes and three kinds of local structure including chains, trees, and ring were analyzed. Through calculation of the topological structure, the spatial topological relations of dwellings were divided into four connection types:courtyards, halls, corridors and composites. On the basis, the overall structure characteristics of hierarchic trees, hierarchic trees with multiple branches, and hierarchic trees with ring relations were combined with the functional attributes of spaces, revealing the isomorphic characteristics of residential lifestyles and spatial layouts. The research showed that the plan design of the dwellings had a certain general organization mode, which reflectd the regional characteristics of organization for dwelling plans. The research of topological structure for dwellings could provid standardized combination forms and design basis for the combination of dwelling plans in the background of industrialization.
2021, 51(4): 74-80.
doi: 10.13204/j.gyjzG20021505
Abstract:
China has been undergoing the phase of rapid city construction for nearly thirty years, in which the city appearance has improved considerably. The massive city construction has come to an end. Megacities, represented by Shanghai, have ascended to the era of stock from the era of increment. How to renovate and update the common buildings that deserve preservation but are not cultural heritages in order to make them both inherit historical traces and adapt to the current using function, and enhance the regional functions, environmental quality and local culture of existing buildings to bring a new life experience to people's lives and save construction costs is the major issue of city construction renewal at present. Two old construction renewal projects of Shanghai Ba Fen Yuan Art Museum and Tongji Architectural Design and Research Institute were taken as examples to analyze the realization of the personalized upgrade and sustainable development of city old buildings by means of reasonable renewal and industrial transformation in the practical activities of analyzing the reuse of old buildings.
China has been undergoing the phase of rapid city construction for nearly thirty years, in which the city appearance has improved considerably. The massive city construction has come to an end. Megacities, represented by Shanghai, have ascended to the era of stock from the era of increment. How to renovate and update the common buildings that deserve preservation but are not cultural heritages in order to make them both inherit historical traces and adapt to the current using function, and enhance the regional functions, environmental quality and local culture of existing buildings to bring a new life experience to people's lives and save construction costs is the major issue of city construction renewal at present. Two old construction renewal projects of Shanghai Ba Fen Yuan Art Museum and Tongji Architectural Design and Research Institute were taken as examples to analyze the realization of the personalized upgrade and sustainable development of city old buildings by means of reasonable renewal and industrial transformation in the practical activities of analyzing the reuse of old buildings.
2021, 51(4): 81-86,80.
doi: 10.13204/j.gyjzG20011708
Abstract:
At present, cities are required to follow the concepts of "smart growth" and "compact city", emphasize multi planning and three line management, and further promoting the utilization of urban stock land to a new height.Due to the negative environmental impact, inconvenient industrial conditions, low land efficiency and other reasons, industrial land in urban central area has become the preferred target for stock renewal. This study aims at how to coordinate the industrial heritage protection and urban renewal. Based on the analysis of the status quo of the residual industrial land, this paper proposes the method of "qualitative+quantitative" method to evaluate and determine the retained heritage objects, and then puts forward the suggestions of "changing the nature of industrial land, transforming and utilizing the industrial heritage, optimizing the spatial renewal and integration. The renewal strategy of "planning management guiding implementation" is to comprehensively coordinate the protection of heritage value and comply with the dual demands of urban renewal, so as to form a renewal mode of coordinating the protection of industrial heritage land.
At present, cities are required to follow the concepts of "smart growth" and "compact city", emphasize multi planning and three line management, and further promoting the utilization of urban stock land to a new height.Due to the negative environmental impact, inconvenient industrial conditions, low land efficiency and other reasons, industrial land in urban central area has become the preferred target for stock renewal. This study aims at how to coordinate the industrial heritage protection and urban renewal. Based on the analysis of the status quo of the residual industrial land, this paper proposes the method of "qualitative+quantitative" method to evaluate and determine the retained heritage objects, and then puts forward the suggestions of "changing the nature of industrial land, transforming and utilizing the industrial heritage, optimizing the spatial renewal and integration. The renewal strategy of "planning management guiding implementation" is to comprehensively coordinate the protection of heritage value and comply with the dual demands of urban renewal, so as to form a renewal mode of coordinating the protection of industrial heritage land.
2021, 51(4): 87-92,153.
doi: 10.13204/j.gyjzG20061404
Abstract:
Aiming at the problem of ecological restoration of mining relics during the construction of characteristic towns, based on the background of the establishment of Tangshan Healthy pension characteristic towns in Nanjing,taking Nanjing Tangshan Mine Park as the research object. According to the sustainable site nitiative (sites), studies the strategies and methods of ecological restoration of mining heritage. Reshape the ecological landscape of characteristic towns, cultivate the cultural connotation of towns, propose measures for the aggregation and upgrading of town industries, and provide decision-making reference for the construction of similar characteristic towns.
Aiming at the problem of ecological restoration of mining relics during the construction of characteristic towns, based on the background of the establishment of Tangshan Healthy pension characteristic towns in Nanjing,taking Nanjing Tangshan Mine Park as the research object. According to the sustainable site nitiative (sites), studies the strategies and methods of ecological restoration of mining heritage. Reshape the ecological landscape of characteristic towns, cultivate the cultural connotation of towns, propose measures for the aggregation and upgrading of town industries, and provide decision-making reference for the construction of similar characteristic towns.
2021, 51(4): 93-98.
doi: 10.13204/j.gyjzG1907130005
Abstract:
Considering the adverse effects of strong wind climbing on transmission towers and sea-crossing bridges under island terrain, an island with the tower engineering construction background along the Zhejiang coast was studied based on Computational Fluid Dynamics. The vertical wind speed distribution of islands with different slopes was studied by numerical simulation, and the vertical wind speed at the top of the slope was fitted. The results showed that the maximum vertical wind speed was at about 3/5 height of the windward slope. Within the height range of 150 m from the measured point to the top of the island, the distribution of the vertical wind speed on the top of the slope with the gradient approximated to an exponential function, and when it exceeded this range, the vertical wind speed remainsed unchanged with the gradient. Under different slope conditions, the maximum vertical wind speed above the top of the slope was in the range of 50~200 m from the top of the slope.
Considering the adverse effects of strong wind climbing on transmission towers and sea-crossing bridges under island terrain, an island with the tower engineering construction background along the Zhejiang coast was studied based on Computational Fluid Dynamics. The vertical wind speed distribution of islands with different slopes was studied by numerical simulation, and the vertical wind speed at the top of the slope was fitted. The results showed that the maximum vertical wind speed was at about 3/5 height of the windward slope. Within the height range of 150 m from the measured point to the top of the island, the distribution of the vertical wind speed on the top of the slope with the gradient approximated to an exponential function, and when it exceeded this range, the vertical wind speed remainsed unchanged with the gradient. Under different slope conditions, the maximum vertical wind speed above the top of the slope was in the range of 50~200 m from the top of the slope.
2021, 51(4): 99-104.
doi: 10.13204/j.gyjzG20030204
Abstract:
The model of parametric vibration for tension suspension cable with horizontal movable boundary is established, and the partial differential vibration equation was derived by Hamilton Principles. According to the boundary constraint, modal superposition method, and Galerkin method, the partial differential equation was transformed into an ordinary differential equation. The modes about resonance of the ordinary differential equation were analyzed by the perturbation method, and the displacement responses of the tension suspension cable under different resonance modes were solved by using the fourth-order Runge-Kutta function. Finally, the safety of the two resonance modes was evaluated by a specific numerical example. The results showed that the displacement of the x-axis in the 1:1:1:1:1 resonance mode was only 31.25% of that in the 1:1:2:1 resonance mode, and the displacement of the z-axis in the 1:1:1:1:1 resonance mode was only 2.181% of that in the 1:1:2:1 resonance mode. The frequency of horizontal excitation was far away from the in-plane natural frequency as far as possible to ensure that the amplitude of the cable was in a safe range.
The model of parametric vibration for tension suspension cable with horizontal movable boundary is established, and the partial differential vibration equation was derived by Hamilton Principles. According to the boundary constraint, modal superposition method, and Galerkin method, the partial differential equation was transformed into an ordinary differential equation. The modes about resonance of the ordinary differential equation were analyzed by the perturbation method, and the displacement responses of the tension suspension cable under different resonance modes were solved by using the fourth-order Runge-Kutta function. Finally, the safety of the two resonance modes was evaluated by a specific numerical example. The results showed that the displacement of the x-axis in the 1:1:1:1:1 resonance mode was only 31.25% of that in the 1:1:2:1 resonance mode, and the displacement of the z-axis in the 1:1:1:1:1 resonance mode was only 2.181% of that in the 1:1:2:1 resonance mode. The frequency of horizontal excitation was far away from the in-plane natural frequency as far as possible to ensure that the amplitude of the cable was in a safe range.
2021, 51(4): 105-110.
doi: 10.13204/j.gyjzG20021002
Abstract:
A new type of bamboo-wood composite joist consisting of a rectangular timber frame and two layers of orthogonal oblique placement bamboo strips connected on both sides was proposed. In order to investigate the flexural capacity of the joists, a total of 4 bamboo-wood composite joists in 2 groups of different timber frame forms were tested respectively, the deformation and failure characteristics of the joists were observed. The load-deflection curves of the specimens were obtained. During the test, the split of bamboo strips showed the sign of joist wreck. The joists performed very good ductility because large deflection occurred from the initial wreck to final failure accompanied with the increasing of load. The results showed that the new type of bamboo-wood composite joists could meet the strength and deformation requirements of floor joists for light wooden structures and low-rise cold-formed thin-walled steel buildings under floor load, and strength failure should not occur within the allowable deflection range. The study could prove the engineering application value of such components, and provide a reference for further technical optimization and theoretical analysis.
A new type of bamboo-wood composite joist consisting of a rectangular timber frame and two layers of orthogonal oblique placement bamboo strips connected on both sides was proposed. In order to investigate the flexural capacity of the joists, a total of 4 bamboo-wood composite joists in 2 groups of different timber frame forms were tested respectively, the deformation and failure characteristics of the joists were observed. The load-deflection curves of the specimens were obtained. During the test, the split of bamboo strips showed the sign of joist wreck. The joists performed very good ductility because large deflection occurred from the initial wreck to final failure accompanied with the increasing of load. The results showed that the new type of bamboo-wood composite joists could meet the strength and deformation requirements of floor joists for light wooden structures and low-rise cold-formed thin-walled steel buildings under floor load, and strength failure should not occur within the allowable deflection range. The study could prove the engineering application value of such components, and provide a reference for further technical optimization and theoretical analysis.
2021, 51(4): 111-117.
doi: 10.13204/j.gyjzG21011108
Abstract:
This paper mainly introduced the key techniques of shaking table test model design and finite element modeling for ductile joint reinforced with cover plate (CPF) and normal steel frame(NSF) considering the floor effect; The contrastive analysis and study on the damage phenomena, strain development in the joint area under the action of severe and mega earthquakes. By using multi-precision shell elements and coupling the translational and rotational degrees of freedom between the floor and the beam upper flange, the finite element analysis results were in good agreement with the experimental results. The results of the comparative analysis of the damage phenomena and strain development law in the joint area showed that CPF steel frame effectively moved the plastic hinge away from the welding at the beam end, in this way, beam hinge failure mechanism of strong column and weak beam, strong joint and weak component was realized. The energy dissipation capacity and bearing capacity of the structure were improved.
This paper mainly introduced the key techniques of shaking table test model design and finite element modeling for ductile joint reinforced with cover plate (CPF) and normal steel frame(NSF) considering the floor effect; The contrastive analysis and study on the damage phenomena, strain development in the joint area under the action of severe and mega earthquakes. By using multi-precision shell elements and coupling the translational and rotational degrees of freedom between the floor and the beam upper flange, the finite element analysis results were in good agreement with the experimental results. The results of the comparative analysis of the damage phenomena and strain development law in the joint area showed that CPF steel frame effectively moved the plastic hinge away from the welding at the beam end, in this way, beam hinge failure mechanism of strong column and weak beam, strong joint and weak component was realized. The energy dissipation capacity and bearing capacity of the structure were improved.
2021, 51(4): 118-125,171.
doi: 10.13204/j.gyjzG20032904
Abstract:
This paper presented an experimental study on the mechanical properties of 40 steel grouted sleeve splices considering the effects of the loading modes (repeated tensile loading, repeated tensile and compression loading at high stress and repeated tensile and compression loading at large strain) and anchorage length (6.5d,7d,8d). The failure modes, load-displacement curves, strain distribution, etc. were studied. The constraint mechanism of the connection specimens and the crack development process of the grouting material were analyzed. The stress distribution in smooth section and deformed section of the sleeve, and the critical anchorage length of the rebar were determined. The test results showed that the failure modes should include the rebar tensile failure and rebar pull-out at the threaded end. The rigidity degeneration of the splices was obvious under cyclic load. The energy-dissipating capacity of specimens decreased with the decrease in anchorage length. The longitudinal and circumferential peak strain positions on the sleeve surface and the bonding stress distribution between the smooth section and the deformed section were significantly affected by the anchorage length of the rebar. The critical anchorage lengths of rebar diameter of 12 mm and 20 mm were 5.42 and 5.48 times the rebar diameter respectively.
This paper presented an experimental study on the mechanical properties of 40 steel grouted sleeve splices considering the effects of the loading modes (repeated tensile loading, repeated tensile and compression loading at high stress and repeated tensile and compression loading at large strain) and anchorage length (6.5d,7d,8d). The failure modes, load-displacement curves, strain distribution, etc. were studied. The constraint mechanism of the connection specimens and the crack development process of the grouting material were analyzed. The stress distribution in smooth section and deformed section of the sleeve, and the critical anchorage length of the rebar were determined. The test results showed that the failure modes should include the rebar tensile failure and rebar pull-out at the threaded end. The rigidity degeneration of the splices was obvious under cyclic load. The energy-dissipating capacity of specimens decreased with the decrease in anchorage length. The longitudinal and circumferential peak strain positions on the sleeve surface and the bonding stress distribution between the smooth section and the deformed section were significantly affected by the anchorage length of the rebar. The critical anchorage lengths of rebar diameter of 12 mm and 20 mm were 5.42 and 5.48 times the rebar diameter respectively.
2021, 51(4): 126-131.
doi: 10.13204/j.gyjzG19110704
Abstract:
The slurry anchor lapping of corrugated pipe restrained by spiral stirrup is a technique to connect assembly components of low cost and simplicity. In order to study the seismic performance of the connection technique, two prefabricated members with slurry anchor lapping of corrugated pipe restrained by spiral stirrup and one cast-in-place structural column were designed and manufactured. The quasi-static load test was carried out to analyze the failure mode, hysteretic curve, skeleton curve, bearing capacity, ductility, stiffness degradation curve and energy dissipation capacity of the structural columns. The test results showed that:1) the slurry anchor lapping of corrugated pipe restrained by spiral stirrup connection technique could effectively connect the precast column, and its seismic performance was better than that of the cast-in-place column on the whole; 2) the crack development and failure mode of the precast structural column were similar with that of the cast-in-place specimen; 3) the seismic performance of the precast column without bonding treatment was slightly worse than that of the cast-in-place column, but the seismic performance of the column base with non-bonding treatment could be improved; 4) the ultimate bearing capacity and ductility coefficient of precast members were higher than that of cast-in-place member; 5) the average secant stiffness degradation curve of precast members was higher than that of cast-in-place member; 6) the energy dissipation capacity of precast members was higher than that of cast-in-place member, and the unbonded treatment of column base was beneficial in improving the energy dissipation capacity of assembly members.
The slurry anchor lapping of corrugated pipe restrained by spiral stirrup is a technique to connect assembly components of low cost and simplicity. In order to study the seismic performance of the connection technique, two prefabricated members with slurry anchor lapping of corrugated pipe restrained by spiral stirrup and one cast-in-place structural column were designed and manufactured. The quasi-static load test was carried out to analyze the failure mode, hysteretic curve, skeleton curve, bearing capacity, ductility, stiffness degradation curve and energy dissipation capacity of the structural columns. The test results showed that:1) the slurry anchor lapping of corrugated pipe restrained by spiral stirrup connection technique could effectively connect the precast column, and its seismic performance was better than that of the cast-in-place column on the whole; 2) the crack development and failure mode of the precast structural column were similar with that of the cast-in-place specimen; 3) the seismic performance of the precast column without bonding treatment was slightly worse than that of the cast-in-place column, but the seismic performance of the column base with non-bonding treatment could be improved; 4) the ultimate bearing capacity and ductility coefficient of precast members were higher than that of cast-in-place member; 5) the average secant stiffness degradation curve of precast members was higher than that of cast-in-place member; 6) the energy dissipation capacity of precast members was higher than that of cast-in-place member, and the unbonded treatment of column base was beneficial in improving the energy dissipation capacity of assembly members.
2021, 51(4): 132-138,147.
doi: 10.13204/j.gyjzG20040902
Abstract:
In order to study the uplift bearing characteristics of the rock-socketed belled pile in sandstone strata, based on the 500 kV double-circuit line project of State Grid, load tests for aixal uplift piles in situ for rock-socketed belled piles were conducted, and the characteristics of the side friction resistance and axial force of piles were obtained, and then a simplified calculation method for the ultimate bearing capacity of rock-socketed belled pile was proposed. The results of field tests showed that the curves of uplift loads and displacement for rock-socketed belled piles were steep, to increase the pile length could effectively improve the ultimate uplift bearing capacity of uplift piles, but with the increase of the pile length, the effect of belled end would decrease and the load bearing ratios of the pile tips and pile shafts gradually decreased from 69.9% to 31.4%; the belled ends of short belled piles bore the uplift loads at initial stages of being loaded, while the belled ends of long rock-socketed piles did not bear loads necessarily, so the belled ends for longer uplift piles were not necessary; when the strength of pile shafts was higher than that of rock around piles, the uplift bearing capacity of test piles was provided by the shear strength of rock around piles, and the ultimate side friction resistance could be equivalent to the shear strength of rock around piles.
In order to study the uplift bearing characteristics of the rock-socketed belled pile in sandstone strata, based on the 500 kV double-circuit line project of State Grid, load tests for aixal uplift piles in situ for rock-socketed belled piles were conducted, and the characteristics of the side friction resistance and axial force of piles were obtained, and then a simplified calculation method for the ultimate bearing capacity of rock-socketed belled pile was proposed. The results of field tests showed that the curves of uplift loads and displacement for rock-socketed belled piles were steep, to increase the pile length could effectively improve the ultimate uplift bearing capacity of uplift piles, but with the increase of the pile length, the effect of belled end would decrease and the load bearing ratios of the pile tips and pile shafts gradually decreased from 69.9% to 31.4%; the belled ends of short belled piles bore the uplift loads at initial stages of being loaded, while the belled ends of long rock-socketed piles did not bear loads necessarily, so the belled ends for longer uplift piles were not necessary; when the strength of pile shafts was higher than that of rock around piles, the uplift bearing capacity of test piles was provided by the shear strength of rock around piles, and the ultimate side friction resistance could be equivalent to the shear strength of rock around piles.
2021, 51(4): 139-147.
doi: 10.13204/j.gyjzG19082020
Abstract:
Tunnel anchorage of suspension bridges is the key components bearing loads from main cables. The bearing capacity of tunnel anchorage was mainly influenced by the parameters of surrounding rocks, embedment depth and the appearance of anchor blocks. In order to further verify the inherent laws and parameter sensitivity, considering the influence factors such as embedment, length of anchor blocks and surrounding rock classification, indoor model tests of tunnel anchorage were designed and conducted, and the effects of the influence factors on the uplift bearing capacity for tunnel anchorage were studied. Based on the related parameters of the indoor model tests, numerical simulations for the indoor model tests were conducted. The results showed the numerical simulation results were in good agreements with the results by the model tests, and the influence factors and the damage characteristics obtained by the model tests were in accordance with the results from the numerical simulations. The main influence factors of the uplift-bearing capacity for tunnel anchorage were the classification of surrounding rock, embedment and bottom angles of anchor blocks, and the influence of the length for the anchor blocks was not obvious.
Tunnel anchorage of suspension bridges is the key components bearing loads from main cables. The bearing capacity of tunnel anchorage was mainly influenced by the parameters of surrounding rocks, embedment depth and the appearance of anchor blocks. In order to further verify the inherent laws and parameter sensitivity, considering the influence factors such as embedment, length of anchor blocks and surrounding rock classification, indoor model tests of tunnel anchorage were designed and conducted, and the effects of the influence factors on the uplift bearing capacity for tunnel anchorage were studied. Based on the related parameters of the indoor model tests, numerical simulations for the indoor model tests were conducted. The results showed the numerical simulation results were in good agreements with the results by the model tests, and the influence factors and the damage characteristics obtained by the model tests were in accordance with the results from the numerical simulations. The main influence factors of the uplift-bearing capacity for tunnel anchorage were the classification of surrounding rock, embedment and bottom angles of anchor blocks, and the influence of the length for the anchor blocks was not obvious.
2021, 51(4): 148-153.
doi: 10.13204/j.gyjzG20072603
Abstract:
In order to study the effect of reinforcement on the bearing capacity of foundation, the limit equilibrium method and slice method were adopted for calculating the ultimate bearing capacity of reinforced foundation in non-cohensive soil based on Terzaghi ultimate bearing capacity theory.The slip blocks of foundation were divided into the active zone, transition zone and passive zone, in which the angle δ1 between the side of the active zone and horizontal plane was not a fixed value but could meet the minimum prinicple of the bearing capacity of the foundation at failure. The sliding surface of the transition zone assumed to be a logarithmic spiral was divided into many triangular slices in calculation. The reinforcement was equivalent to tensile forces acting on the blocks. Based on the limit equilibrium theory, the force equilibrum formulas on the passive zone, active zone and transition zone were established,which could calculate the angles of δ1 corresponding to the ultimate bearing capacity of foundation. By optimizing δ1, the minimum bearing capacity of foundation could be calculated. The effects of the layers of being reinforced, embedment, spacing, length and internal friction angles on the bearing capacity of foundation were also analyzed. By comparison with experimental data, the feasibility of the method was verified.
In order to study the effect of reinforcement on the bearing capacity of foundation, the limit equilibrium method and slice method were adopted for calculating the ultimate bearing capacity of reinforced foundation in non-cohensive soil based on Terzaghi ultimate bearing capacity theory.The slip blocks of foundation were divided into the active zone, transition zone and passive zone, in which the angle δ1 between the side of the active zone and horizontal plane was not a fixed value but could meet the minimum prinicple of the bearing capacity of the foundation at failure. The sliding surface of the transition zone assumed to be a logarithmic spiral was divided into many triangular slices in calculation. The reinforcement was equivalent to tensile forces acting on the blocks. Based on the limit equilibrium theory, the force equilibrum formulas on the passive zone, active zone and transition zone were established,which could calculate the angles of δ1 corresponding to the ultimate bearing capacity of foundation. By optimizing δ1, the minimum bearing capacity of foundation could be calculated. The effects of the layers of being reinforced, embedment, spacing, length and internal friction angles on the bearing capacity of foundation were also analyzed. By comparison with experimental data, the feasibility of the method was verified.
2021, 51(4): 154-160.
doi: 10.13204/j.gyjzG20062604
Abstract:
The effect of nano-TiO2 particles on the compressive, tensile and freeze-thaw durability of concrete was studied, and the normal concrete and the nano-TiO2 concrete were simulated at room temperature by PFC 2D. The results showed that the nano-TiO2 particles could improve the compactness of concrete, at room temperature, 3% nano-TiO2 particles had the most improvement in concrete compressive strength, which was 20.18% higher than normal concrete. The tensile performance of nano-TiO2 concrete was unchanged, but the freeze-thaw resistance of nano-TiO2 concrete had been greatly improved. After being subjected to 100 freeze-thaw cycles, its freeze resistance increased by 136.8% compared to normal concrete. PFC 2D could well simulate the compressive and tensile mechanical properties of normal concrete and nano-particle modified concrete. Due to the discreteness of concrete, there was a slight difference between the simulated and experimental stress and strain trends, but it could accurately reflect its peak stress and strain.
The effect of nano-TiO2 particles on the compressive, tensile and freeze-thaw durability of concrete was studied, and the normal concrete and the nano-TiO2 concrete were simulated at room temperature by PFC 2D. The results showed that the nano-TiO2 particles could improve the compactness of concrete, at room temperature, 3% nano-TiO2 particles had the most improvement in concrete compressive strength, which was 20.18% higher than normal concrete. The tensile performance of nano-TiO2 concrete was unchanged, but the freeze-thaw resistance of nano-TiO2 concrete had been greatly improved. After being subjected to 100 freeze-thaw cycles, its freeze resistance increased by 136.8% compared to normal concrete. PFC 2D could well simulate the compressive and tensile mechanical properties of normal concrete and nano-particle modified concrete. Due to the discreteness of concrete, there was a slight difference between the simulated and experimental stress and strain trends, but it could accurately reflect its peak stress and strain.
2021, 51(4): 161-166,203.
doi: 10.13204/j.gyjzG20101904
Abstract:
In order to solve the problems of fast setting time and poor operability of magnesium phosphate cement, metakaolin and hollow glass microbeads were used to modify the cement, and magnesium phosphate cement with properties of reinforcement material was prepared. The influence of metakaolin and hollow glass microbeads on cement strength, setting time and working performance were studied. The results showed that when the mass ratio of magnesium oxide and potassium dihydrogen phosphate was 1-1.5, the setting time gradually lengthens and the strength declined as the content of metakaolin increased. The content of metakaolin should be 0.5-0.8. With the increase of the content of hollow glass microbeads, the setting time tended to prolong, the fluidity increased significantly and the strength decreased slightly. The optimal content of hollow glass microbeads was 0.08-0.12. The magnesium phosphate cement prepared had controllable setting time, reliable strength, and low apparent density, which could meet the requirements of reinforcement materials.
In order to solve the problems of fast setting time and poor operability of magnesium phosphate cement, metakaolin and hollow glass microbeads were used to modify the cement, and magnesium phosphate cement with properties of reinforcement material was prepared. The influence of metakaolin and hollow glass microbeads on cement strength, setting time and working performance were studied. The results showed that when the mass ratio of magnesium oxide and potassium dihydrogen phosphate was 1-1.5, the setting time gradually lengthens and the strength declined as the content of metakaolin increased. The content of metakaolin should be 0.5-0.8. With the increase of the content of hollow glass microbeads, the setting time tended to prolong, the fluidity increased significantly and the strength decreased slightly. The optimal content of hollow glass microbeads was 0.08-0.12. The magnesium phosphate cement prepared had controllable setting time, reliable strength, and low apparent density, which could meet the requirements of reinforcement materials.
2021, 51(4): 167-171.
doi: 10.13204/j.gyjzG20031602
Abstract:
Both rice husk ash and metakaolin are pozzolanic active materials. In the experiment,chemical slurry of rice husk ash and metakaolin were used to strengthen the recycled coarse aggregate. The effects of chemical slurry on the properties of recycled coarse aggregate and the properties of recycled concrete prepared were tested. Studies showed that the properties of recycled coarse aggregate and recycled concrete could be optimized by 5 different ratios of chemical slurry. When the mixing ratio of rice husk ash and metakaolin was 3:1, the crushing index of recycled coarse aggregate decreased by 1.5%, the void ratio decreased by 2.4%,the apparent density and bulk density improved,the water absorption increased by 2.2%.Compared with the reference group, the compressive strength of recycled concrete prepared with reinforced aggregate increased by 8.6%, the flexural strength increased by 4.4% and the wear resistance was better.
Both rice husk ash and metakaolin are pozzolanic active materials. In the experiment,chemical slurry of rice husk ash and metakaolin were used to strengthen the recycled coarse aggregate. The effects of chemical slurry on the properties of recycled coarse aggregate and the properties of recycled concrete prepared were tested. Studies showed that the properties of recycled coarse aggregate and recycled concrete could be optimized by 5 different ratios of chemical slurry. When the mixing ratio of rice husk ash and metakaolin was 3:1, the crushing index of recycled coarse aggregate decreased by 1.5%, the void ratio decreased by 2.4%,the apparent density and bulk density improved,the water absorption increased by 2.2%.Compared with the reference group, the compressive strength of recycled concrete prepared with reinforced aggregate increased by 8.6%, the flexural strength increased by 4.4% and the wear resistance was better.
2021, 51(4): 172-180.
doi: 10.13204/j.gyjzG20123002
Abstract:
The HS-Small model (the HSS model) was proposed based on the hardening soil model (the HS model) considering the small strain characteristics of soils, which is more accurate in simulating and predicting the deformation of underground engineerings and can meet the strict deformation control requirements, the numerical analysis results by the HSS model agree well with the measured data. Therefore, more and more numerical analysis of underground engineerings have adopted the HSS model. However, the HSS model has many parameters, and it is difficult and inconvenient to obtain the parameter values. Conventional geological survey reports hardly provide the relevant parameter values of the HSS model, and some high-precision, long-period indoor tests need to be conducted to measure them. Therefore, it is necessary and meaningful to summarize the research status of parameter selection for the HSS model, which can provide engineering experiences and reference to subsequent projects. On the basis of research on a large number of documents at home and abroad, the calculating methods for parameters of the HSS model and the recommended values were summarized.On the other hand, some deficiencies in existing research results were pointed out,which could provide some reference to further research.
The HS-Small model (the HSS model) was proposed based on the hardening soil model (the HS model) considering the small strain characteristics of soils, which is more accurate in simulating and predicting the deformation of underground engineerings and can meet the strict deformation control requirements, the numerical analysis results by the HSS model agree well with the measured data. Therefore, more and more numerical analysis of underground engineerings have adopted the HSS model. However, the HSS model has many parameters, and it is difficult and inconvenient to obtain the parameter values. Conventional geological survey reports hardly provide the relevant parameter values of the HSS model, and some high-precision, long-period indoor tests need to be conducted to measure them. Therefore, it is necessary and meaningful to summarize the research status of parameter selection for the HSS model, which can provide engineering experiences and reference to subsequent projects. On the basis of research on a large number of documents at home and abroad, the calculating methods for parameters of the HSS model and the recommended values were summarized.On the other hand, some deficiencies in existing research results were pointed out,which could provide some reference to further research.
2021, 51(4): 181-188.
doi: 10.13204/j.gyjzG21052612
Abstract:
Research progress was introduced in the paper concerning the bearing capacity of concrete-infilled double steel corrugated-plate composite walls with T-section (T-CDSCW), including cross-sectional capacity, integral stability, and relevant experimental study and finite element analysis. Due to the excellent bearing capacity, CDSCWs have broad application prospects in high-rise buildings. The T-CDSCW is composed of flange and web wall elements and rectangular concrete-filled steel tubular boundary elements. The design of bearing capacity involves the local buckling of steel corrugated-plates, the cross-sectional capacity under axial compression and biaxial bending moment, and the integral stability under axial compression and both axial compression and bending in the web plane. The failure modes in the experiments were the local buckling of steel tubes and corrugated-plates, the flexural buckling of the T-CDSCW, and the flexural failure under cyclic loading. The bearing capacity and seismic performance could be simulated by refined and simplified finite element models. Some of the design formulas introduced in the paper have been adopted in Technical Specification for Structures with Corrugated Steel Plate Components (T/CECS 624-2019), and related experimental research and finite element analysis could provide the basis for the compilation of the standard.
Research progress was introduced in the paper concerning the bearing capacity of concrete-infilled double steel corrugated-plate composite walls with T-section (T-CDSCW), including cross-sectional capacity, integral stability, and relevant experimental study and finite element analysis. Due to the excellent bearing capacity, CDSCWs have broad application prospects in high-rise buildings. The T-CDSCW is composed of flange and web wall elements and rectangular concrete-filled steel tubular boundary elements. The design of bearing capacity involves the local buckling of steel corrugated-plates, the cross-sectional capacity under axial compression and biaxial bending moment, and the integral stability under axial compression and both axial compression and bending in the web plane. The failure modes in the experiments were the local buckling of steel tubes and corrugated-plates, the flexural buckling of the T-CDSCW, and the flexural failure under cyclic loading. The bearing capacity and seismic performance could be simulated by refined and simplified finite element models. Some of the design formulas introduced in the paper have been adopted in Technical Specification for Structures with Corrugated Steel Plate Components (T/CECS 624-2019), and related experimental research and finite element analysis could provide the basis for the compilation of the standard.
2021, 51(4): 189-193.
doi: 10.13204/j.gyjzG201903190009
Abstract:
Fiber-reinforced polymer (FRP) composites are widely externally bonded on or near surface mounted into the tension side of reinforced concrete (RC) beams to enhance the flexural capacity. Such a technique becomes one of the mainstream techniques for the flexural strengthening of RC beams. FRP plated RC beams usually fail due to debonding failure in either intermediate crack induced debonding (IC debonding) or concrete cover debonding. The debonding failure usually occurs with the maximum strain of the FRP being only 20%~40% of its rupture strain, thus limiting the utilization of the high tensile strength of the materials. Appropriate anchorages can effectively suppress or delay the occurrence of the debonding failure, thus improving the strengthening efficiency and the utilization of the materials. The scholars at home and abroad have proposed different forms of anchoring measures, and their effects, durability, and construction complexity are different. The oblique U-jacket was proposed to suppress or mitigate the concrete cover debonding of RC beams. Four full-scale RC beams strengthened by FRP with or without end oblique U-jacket to identify the effect of the U-jacket on the suppression or mitigation of concrete cover debonding. The test results showed that the ultimate bearing capacity and ductility of the tested beams with externally bonded and near surface mounted reinforced concrete beams could be increased by 62.03% and 117.85%, 61.08% and 155.44%, respectively.
Fiber-reinforced polymer (FRP) composites are widely externally bonded on or near surface mounted into the tension side of reinforced concrete (RC) beams to enhance the flexural capacity. Such a technique becomes one of the mainstream techniques for the flexural strengthening of RC beams. FRP plated RC beams usually fail due to debonding failure in either intermediate crack induced debonding (IC debonding) or concrete cover debonding. The debonding failure usually occurs with the maximum strain of the FRP being only 20%~40% of its rupture strain, thus limiting the utilization of the high tensile strength of the materials. Appropriate anchorages can effectively suppress or delay the occurrence of the debonding failure, thus improving the strengthening efficiency and the utilization of the materials. The scholars at home and abroad have proposed different forms of anchoring measures, and their effects, durability, and construction complexity are different. The oblique U-jacket was proposed to suppress or mitigate the concrete cover debonding of RC beams. Four full-scale RC beams strengthened by FRP with or without end oblique U-jacket to identify the effect of the U-jacket on the suppression or mitigation of concrete cover debonding. The test results showed that the ultimate bearing capacity and ductility of the tested beams with externally bonded and near surface mounted reinforced concrete beams could be increased by 62.03% and 117.85%, 61.08% and 155.44%, respectively.
2021, 51(4): 194-198,212.
doi: 10.13204/j.gyjzG19122310
Abstract:
In order to study the flexural performance of engineered cementious composite (ECC) -concrete composite beams equipped with fiber reinforced polymer (FRP) steel bars and ordinary steel bars, the bending failure of 32 composite beams with mixed FRP bars and ordinary steel bars with different ECC height replacement rates was tested by a four-point loading test. The test results showed that, because the fiber material in ECC had excellent tensile properties, compared with ordinary concrete beams with the same reinforcement, cracking, yielding, ultimate bending moment and stiffness of hybrid and ECC beams were improved. The average crack spacing and width decreased with the increase of ECC height replacement rate. Although the reinforcement ratio of traditional ordinary concrete beams and hybrid reinforced composite beams was basically the same, the ductility of hybrid reinforced composite beams is higher than that of ordinary concrete beams, reinforced BFC beams had good energy dissipation capacity due to their excellent deformation capacity.
In order to study the flexural performance of engineered cementious composite (ECC) -concrete composite beams equipped with fiber reinforced polymer (FRP) steel bars and ordinary steel bars, the bending failure of 32 composite beams with mixed FRP bars and ordinary steel bars with different ECC height replacement rates was tested by a four-point loading test. The test results showed that, because the fiber material in ECC had excellent tensile properties, compared with ordinary concrete beams with the same reinforcement, cracking, yielding, ultimate bending moment and stiffness of hybrid and ECC beams were improved. The average crack spacing and width decreased with the increase of ECC height replacement rate. Although the reinforcement ratio of traditional ordinary concrete beams and hybrid reinforced composite beams was basically the same, the ductility of hybrid reinforced composite beams is higher than that of ordinary concrete beams, reinforced BFC beams had good energy dissipation capacity due to their excellent deformation capacity.
2021, 51(4): 199-203.
doi: 10.13204/j.gyjzG20051402
Abstract:
The marine environment has very high requirements for the performance of anticorrosive coatings for steel structures, especially the adhesion between steel and coatings, which is the basis of anticorrosive coatings. The influence of flake type, flake content, flake particle size, curing agent type and curing agent proportion on coating adhesion was studied by conducting tests on 18 specimens and using epoxy resin as the substrate. The adhesion of the coating reached the maximum when the basalt flake content was 20%, the particle size was 400, the curing agent was polyamide, and the ratio of epoxy resin to polyamide was 2:1.
The marine environment has very high requirements for the performance of anticorrosive coatings for steel structures, especially the adhesion between steel and coatings, which is the basis of anticorrosive coatings. The influence of flake type, flake content, flake particle size, curing agent type and curing agent proportion on coating adhesion was studied by conducting tests on 18 specimens and using epoxy resin as the substrate. The adhesion of the coating reached the maximum when the basalt flake content was 20%, the particle size was 400, the curing agent was polyamide, and the ratio of epoxy resin to polyamide was 2:1.
2021, 51(4): 204-212.
doi: 10.13204/j.gyjzG20102206
Abstract:
Spherical structure is a difficulty in construction design, especially for the hybrid structure with external spherical space grid structure and internal multi-layer irregular system which are few cases at present. The basic layout and seismic analysis of the spherical Exhibition Center of Suzhou high speed railway new city was introduced. The special-shaped curved surface of the structure adopts the steel structure bidirectional cross space grid structure system; the horizontal lateral resistance system adopts the steel frame concrete shear wall system with four core tubes and circular steel tube columns; in the vertical bearing system, the horizontal floor beam adopts the steel beam, the secondary beam adopts the steel reinforced concrete composite beam, and the floor adopts the steel truss floor bearing plate; in order to meet the needs of large space development from one to three floors Hall function, 3.5 m high steel truss is set to hang the frame column and floor of the lower seven floors. Through the simulation of small, medium and rare earthquakes, the overall safety of the structure is analyzed, and the key components such as shear wall, suspension truss, steel cover and key joints of truss suspension are specially analyzed. All indexes meet the requirements, and the purpose of structural seismic design is achieved.
Spherical structure is a difficulty in construction design, especially for the hybrid structure with external spherical space grid structure and internal multi-layer irregular system which are few cases at present. The basic layout and seismic analysis of the spherical Exhibition Center of Suzhou high speed railway new city was introduced. The special-shaped curved surface of the structure adopts the steel structure bidirectional cross space grid structure system; the horizontal lateral resistance system adopts the steel frame concrete shear wall system with four core tubes and circular steel tube columns; in the vertical bearing system, the horizontal floor beam adopts the steel beam, the secondary beam adopts the steel reinforced concrete composite beam, and the floor adopts the steel truss floor bearing plate; in order to meet the needs of large space development from one to three floors Hall function, 3.5 m high steel truss is set to hang the frame column and floor of the lower seven floors. Through the simulation of small, medium and rare earthquakes, the overall safety of the structure is analyzed, and the key components such as shear wall, suspension truss, steel cover and key joints of truss suspension are specially analyzed. All indexes meet the requirements, and the purpose of structural seismic design is achieved.
