Login
Register
E-alert
2024 Vol. 54, No. 3
Display Method:
2024, 54(3): 1-8.
doi: 10.3724/j.gyjzG23042512
Abstract:
The value assessment of industrial heritage is based on comparing industrial heritage of the same type. At present, the research of industrial heritage in China still lacks detailed classification and evaluation. Meanwhile, how to find the proper position of heritage in the industrial layout system is also a critical issue. The study traced the evolution of the industrial classification in modern China, sorted out the changes in classification that had been spawned by the introduction of the Western 16 classification into China, i.e. the gradual refinement from the development of the 16 classification to the 30 classification, with several surveys organized by the Executive Yuan, the Legislative Yuan and Accounting Division of the National Government of the Republic of China, as well as in-depth studies conducted by researchers based on the results of the surveys, which comprehensively presented the development of the modern industrial classification. On the basis of sorting out the course of modern industrial classification, the paper integrated the modern classifications into a framework to establish a complete genealogy for the identity of modern industrial heritage and laid the foundation for further in-depth evaluation and presentation.
The value assessment of industrial heritage is based on comparing industrial heritage of the same type. At present, the research of industrial heritage in China still lacks detailed classification and evaluation. Meanwhile, how to find the proper position of heritage in the industrial layout system is also a critical issue. The study traced the evolution of the industrial classification in modern China, sorted out the changes in classification that had been spawned by the introduction of the Western 16 classification into China, i.e. the gradual refinement from the development of the 16 classification to the 30 classification, with several surveys organized by the Executive Yuan, the Legislative Yuan and Accounting Division of the National Government of the Republic of China, as well as in-depth studies conducted by researchers based on the results of the surveys, which comprehensively presented the development of the modern industrial classification. On the basis of sorting out the course of modern industrial classification, the paper integrated the modern classifications into a framework to establish a complete genealogy for the identity of modern industrial heritage and laid the foundation for further in-depth evaluation and presentation.
2024, 54(3): 9-17.
doi: 10.3724/j.gyjzG23042402
Abstract:
This paper introduced the current situation of industrial heritage protection and industrial heritage under the framework of historical and cultural city protection in Fuzhou, and through the analysis of two protection practices of Fujian Mawei Shipping Administration Historical Area, Fuda Yishan Cultural and Creative Industrial Park, the issues encountered in the delineation of the protection scope of industrial heritage (core), construction activity protection control, etc., were summarized from the perspective of historical sections corresponding to the protection framework of Fuzhou's historical and cultural cities. The paper proposed reasonable methods for delineating protection scope and planning control for industrial heritage areas that are both historical sections and have cultural relics protection units, industrial heritage areas with cultural relics protection units but not historical sections, and industrial heritage areas with only historical buildings but no cultural relics protection units or historical sections. It pointed out that the solution to current problems required revision and improvement of protection documents and effective coordination with different planning.
This paper introduced the current situation of industrial heritage protection and industrial heritage under the framework of historical and cultural city protection in Fuzhou, and through the analysis of two protection practices of Fujian Mawei Shipping Administration Historical Area, Fuda Yishan Cultural and Creative Industrial Park, the issues encountered in the delineation of the protection scope of industrial heritage (core), construction activity protection control, etc., were summarized from the perspective of historical sections corresponding to the protection framework of Fuzhou's historical and cultural cities. The paper proposed reasonable methods for delineating protection scope and planning control for industrial heritage areas that are both historical sections and have cultural relics protection units, industrial heritage areas with cultural relics protection units but not historical sections, and industrial heritage areas with only historical buildings but no cultural relics protection units or historical sections. It pointed out that the solution to current problems required revision and improvement of protection documents and effective coordination with different planning.
2024, 54(3): 18-24.
doi: 10.3724/j.gyjzG23062607
Abstract:
This paper introduced the current situation of industrial heritage protection and industrial heritagization under the framework of protection for historical and cultural cities in Fuzhou, and through the analysis of heritage buildings in the former site of Mawei Shipyard and the historical buildings in Fuda Industrial Park, the problems encountered by industrial heritage in the protection of the main body were summarized from the level of cultural relics and monuments under the protection framework of Fuzhou famous historic and cultural cities corresponding to industrial heritage. Some of the possible solutions such as formulating regional norms and revising the Guidelines were proposed to solve the problem of unreasonable transformation and utilization of large space in industrial heritage.
This paper introduced the current situation of industrial heritage protection and industrial heritagization under the framework of protection for historical and cultural cities in Fuzhou, and through the analysis of heritage buildings in the former site of Mawei Shipyard and the historical buildings in Fuda Industrial Park, the problems encountered by industrial heritage in the protection of the main body were summarized from the level of cultural relics and monuments under the protection framework of Fuzhou famous historic and cultural cities corresponding to industrial heritage. Some of the possible solutions such as formulating regional norms and revising the Guidelines were proposed to solve the problem of unreasonable transformation and utilization of large space in industrial heritage.
2024, 54(3): 25-37.
doi: 10.3724/j.gyjzG23090706
Abstract:
Taking the data of “the third national survey of cultural relics” and the industrial heritage data obtained from on-site investigation as the research objects, ArcGIS spatial analysis and mathematical statistics were used to study the temporal and spatial evolution characteristics of industrial heritage in Jiangxi Province and explore its influencing factors. The results showed that: 1) from the perspective of time distribution, the industrial heritage of Jiangxi Province has the characteristics of large time span, uneven distribution and prominent stages, and is mainly modern industrial heritage; 2) from the perspective of spatial distribution, the industrial heritage of Jiangxi Province is concentrated in northwest Jiangxi and southern Jiangxi, forming a spatial pattern of “two cores, two pairs, and zonal distribution” in space; 3) from the perspective of heritage type, the industrial heritage light industry in Jiangxi Province is evenly distributed in blocks, and the other four types of light industry are scattered; 4) from the perspective of time evolution, the spatial distribution of industrial heritage in Jiangxi Province has four obvious transitions; 5) from the perspective of influencing factors, the analysis results of geographic detectors and spatial superposition analysis show that the spatial and temporal distribution differences of industrial heritage in Jiangxi Province are affected by multiple factors. Among them, government policies, river systems, road traffic, and industrial level are strong influencing factors.
Taking the data of “the third national survey of cultural relics” and the industrial heritage data obtained from on-site investigation as the research objects, ArcGIS spatial analysis and mathematical statistics were used to study the temporal and spatial evolution characteristics of industrial heritage in Jiangxi Province and explore its influencing factors. The results showed that: 1) from the perspective of time distribution, the industrial heritage of Jiangxi Province has the characteristics of large time span, uneven distribution and prominent stages, and is mainly modern industrial heritage; 2) from the perspective of spatial distribution, the industrial heritage of Jiangxi Province is concentrated in northwest Jiangxi and southern Jiangxi, forming a spatial pattern of “two cores, two pairs, and zonal distribution” in space; 3) from the perspective of heritage type, the industrial heritage light industry in Jiangxi Province is evenly distributed in blocks, and the other four types of light industry are scattered; 4) from the perspective of time evolution, the spatial distribution of industrial heritage in Jiangxi Province has four obvious transitions; 5) from the perspective of influencing factors, the analysis results of geographic detectors and spatial superposition analysis show that the spatial and temporal distribution differences of industrial heritage in Jiangxi Province are affected by multiple factors. Among them, government policies, river systems, road traffic, and industrial level are strong influencing factors.
2024, 54(3): 38-45.
doi: 10.3724/j.gyjzG23042007
Abstract:
The integration and interaction between the protective reuse of industrial heritage and sustainable urban development has always been a concern and urgent solution for decision-makers such as the government and enterprises. From the perspective of multi-attribute decision-making, the application of the "PROMETHEE" theory can effectively assist in decision-making on the reuse of industrial heritage. Based on the PROMETHEE multicriteria and multi-attribute analysis theory, taking six industrial heritage sites in Qingdao as an example, a practical and feasible method for ranking and selecting strengths and weaknesses in industrial heritage reuse strategies was proposed by using various comprehensive analysis methods such as qualitative and quantitative analysis. This can provide theoretical basis for finding the most suitable reuse strategies and models for heritage sites, and provide a suitable practical method for solving the problem of high-quality reuse of industrial heritage. Research has found that it used to be difficult to determine the inheritance of reuse methods through empirical analysis, and data analysis using the PROMETHEE multi-criteria decision-making method can help make decision judgments. Among the six selected cases in the research institute, based on the PROMETHEE theory, the most suitable reuse strategies and methods were found for each of the six heritage sites.
The integration and interaction between the protective reuse of industrial heritage and sustainable urban development has always been a concern and urgent solution for decision-makers such as the government and enterprises. From the perspective of multi-attribute decision-making, the application of the "PROMETHEE" theory can effectively assist in decision-making on the reuse of industrial heritage. Based on the PROMETHEE multicriteria and multi-attribute analysis theory, taking six industrial heritage sites in Qingdao as an example, a practical and feasible method for ranking and selecting strengths and weaknesses in industrial heritage reuse strategies was proposed by using various comprehensive analysis methods such as qualitative and quantitative analysis. This can provide theoretical basis for finding the most suitable reuse strategies and models for heritage sites, and provide a suitable practical method for solving the problem of high-quality reuse of industrial heritage. Research has found that it used to be difficult to determine the inheritance of reuse methods through empirical analysis, and data analysis using the PROMETHEE multi-criteria decision-making method can help make decision judgments. Among the six selected cases in the research institute, based on the PROMETHEE theory, the most suitable reuse strategies and methods were found for each of the six heritage sites.
2024, 54(3): 46-53.
doi: 10.3724/j.gyjzG23042001
Abstract:
On the basis of determining the influencing factors of industrial tourism development value and building an evaluation system, the paper evaluated the factors affecting industrial heritage tourism value, and determined the important factors affecting industrial heritage tourism development according to the index weight of each influencing factor, which is convenient for scientific decision-making of industrial tourism development. Using historical document analysis, Delphi method and analytic hierarchy process, the study confirmed that the 10 key factors of industrial heritage tourism development should be the convenience of transportation, richness of exhibition content, accommodation facilities, suitability of tourism participation activities, market scale of mass tourists, number of tourists in heritage sites, interest in tourism process, beauty of sightseeing and viewing, grade of heritage sites, and influence on history. On this basis, the paper put forward three industrial heritage tourism development strategies: “industrial heritage + cultural tourism”, “industrial heritage + intelligent tourism”, “industrial heritage + popular science and ecological education tourism”.
On the basis of determining the influencing factors of industrial tourism development value and building an evaluation system, the paper evaluated the factors affecting industrial heritage tourism value, and determined the important factors affecting industrial heritage tourism development according to the index weight of each influencing factor, which is convenient for scientific decision-making of industrial tourism development. Using historical document analysis, Delphi method and analytic hierarchy process, the study confirmed that the 10 key factors of industrial heritage tourism development should be the convenience of transportation, richness of exhibition content, accommodation facilities, suitability of tourism participation activities, market scale of mass tourists, number of tourists in heritage sites, interest in tourism process, beauty of sightseeing and viewing, grade of heritage sites, and influence on history. On this basis, the paper put forward three industrial heritage tourism development strategies: “industrial heritage + cultural tourism”, “industrial heritage + intelligent tourism”, “industrial heritage + popular science and ecological education tourism”.
2024, 54(3): 54-62.
doi: 10.3724/j.gyjzG23042406
Abstract:
It is extremely important to explore how to closely adjust the protection and reuse of industrial relics to current events and situations under national and local policies. Taking the Xinglin old industrial zone in Jimei, District of Xiamen as an example, this study investigated and sorted out the evolution of the Xinglin old industrial zone, studied the urban industrial landscape, planning layout, architectural space and structural characteristics, and considerd the possibility of the construction of a youth-friendly city and the reuse of industrial relics. On this basis, combined with policies such as the “Action Plan for Building a Youth Friendly Urban Area in Jimei District”, the paper explored the strategies for the reuse of industrial relics in the context of construction of youth-friendly cities from the perspectives of youth entrepreneurship and employment friendliness, youth life friendliness, school village and student friendliness, Taiwan youth integration and youth growth friendliness, and analyzed them through the Xiamen Textile Factory renovation project.
It is extremely important to explore how to closely adjust the protection and reuse of industrial relics to current events and situations under national and local policies. Taking the Xinglin old industrial zone in Jimei, District of Xiamen as an example, this study investigated and sorted out the evolution of the Xinglin old industrial zone, studied the urban industrial landscape, planning layout, architectural space and structural characteristics, and considerd the possibility of the construction of a youth-friendly city and the reuse of industrial relics. On this basis, combined with policies such as the “Action Plan for Building a Youth Friendly Urban Area in Jimei District”, the paper explored the strategies for the reuse of industrial relics in the context of construction of youth-friendly cities from the perspectives of youth entrepreneurship and employment friendliness, youth life friendliness, school village and student friendliness, Taiwan youth integration and youth growth friendliness, and analyzed them through the Xiamen Textile Factory renovation project.
2024, 54(3): 63-71.
doi: 10.3724/j.gyjzG23042504
Abstract:
This paper systematically combed the building structure, components, materials, etc. of Xiamen Haicang Juren House, and used the information surveying and mapping technique and HBIM technique to establish a family library of historical building components and HBIM building information model. Based on HBIM, record management and visual analysis were carried out for the historical information, current status and damaged information of Juren House; the phased information of repair construction was recorded based on the secondary development plug-in. On the one hand, the 3D model considered the information of survey and reparir construction, so as to check, updata, and manage data information in real time; on the other hand, the data of the HBIM model were enriched. The technical route of integrating point cloud data obtained from various digital surveying and mapping mehtods is of exploratory significance for the complete data acquisition of modem architecture heritage in southern Fujian, and has fundamental value for the construction of the family library of modern architectural heritage, component model and technical drawing, as well as the practical application in repair design.
This paper systematically combed the building structure, components, materials, etc. of Xiamen Haicang Juren House, and used the information surveying and mapping technique and HBIM technique to establish a family library of historical building components and HBIM building information model. Based on HBIM, record management and visual analysis were carried out for the historical information, current status and damaged information of Juren House; the phased information of repair construction was recorded based on the secondary development plug-in. On the one hand, the 3D model considered the information of survey and reparir construction, so as to check, updata, and manage data information in real time; on the other hand, the data of the HBIM model were enriched. The technical route of integrating point cloud data obtained from various digital surveying and mapping mehtods is of exploratory significance for the complete data acquisition of modem architecture heritage in southern Fujian, and has fundamental value for the construction of the family library of modern architectural heritage, component model and technical drawing, as well as the practical application in repair design.
2024, 54(3): 72-79.
doi: 10.3724/j.gyjzG21112510
Abstract:
Along with the transformation of tourism and the increase of tourists in traditional villages, the spatial forms and functions are confronted with protection, adjustment and evolution. This study summarized the organizational patterns and design strategies within tourists' behavior demand-oriented Huizhou villages by analyzing organization characteristics of villages’ spatial factors and tourists' behavioral needs.The analysis showed that there were differences in spatial factors and organizational patterns for different activities. Under the guidance of different behavioral needs, the organization of space could be summarized as follows: 1) organizational pattern with direct correlation of space factors; 2) organizational pattern with necessary conditions; 3) organization pattern with compound function orientation. Local existing spatial factors were combined to form a variety of spatial patterns, which could promote the demand-oriented spatial adaptation, the maintenance of spatial forms, and the improvement of theories and practical strategies related to village spatial design and construction.
Along with the transformation of tourism and the increase of tourists in traditional villages, the spatial forms and functions are confronted with protection, adjustment and evolution. This study summarized the organizational patterns and design strategies within tourists' behavior demand-oriented Huizhou villages by analyzing organization characteristics of villages’ spatial factors and tourists' behavioral needs.The analysis showed that there were differences in spatial factors and organizational patterns for different activities. Under the guidance of different behavioral needs, the organization of space could be summarized as follows: 1) organizational pattern with direct correlation of space factors; 2) organizational pattern with necessary conditions; 3) organization pattern with compound function orientation. Local existing spatial factors were combined to form a variety of spatial patterns, which could promote the demand-oriented spatial adaptation, the maintenance of spatial forms, and the improvement of theories and practical strategies related to village spatial design and construction.
2024, 54(3): 80-89.
doi: 10.3724/j.gyjzG23060703
Abstract:
On the basis of finding out the background of heritage resources, analyzing the composition of heritage value, and following the law of heritage work, the protection pattern of linear cultural heritage network can be clarified, which can provide a scientific basis for its systematic protection and development. Therefore, by means of historical literature research, geospatial analysis, principal component analysis and other methods, the identification, feature analysis and value assessment of the “heritage sources” of Hui-Hang Ancient Road were completed. Based on the analysis results, the protection scope of four spatial levels, namely the whole area, the ancient road network, the heritage protection area and the heritage resource point, was defined. At the same time, the key points of protection, activation and utilization at all levels were proposed in order to promote the overall protection of heritage resources along the Hui-Hang Ancient Road.
On the basis of finding out the background of heritage resources, analyzing the composition of heritage value, and following the law of heritage work, the protection pattern of linear cultural heritage network can be clarified, which can provide a scientific basis for its systematic protection and development. Therefore, by means of historical literature research, geospatial analysis, principal component analysis and other methods, the identification, feature analysis and value assessment of the “heritage sources” of Hui-Hang Ancient Road were completed. Based on the analysis results, the protection scope of four spatial levels, namely the whole area, the ancient road network, the heritage protection area and the heritage resource point, was defined. At the same time, the key points of protection, activation and utilization at all levels were proposed in order to promote the overall protection of heritage resources along the Hui-Hang Ancient Road.
2024, 54(3): 90-96.
doi: 10.3724/j.gyjzG23053004
Abstract:
In order to study the wind environment problems in the old community, taking the residential zone of Henan University of Science and Technology in Luoyang City, Henan Province, as the research object, taking the original meteorological data of Zhengzhou City as the data source, substituting it into Phoenics as a boundary condition to simulate the wind environment, and combining the relevant technical standards of green buildings to analyze the wind speed and wind pressure of the dominant wind in July. Some improvement measures for the existing wind environment problems in the campus were provided, and the wind environment was simulated again after the improvement. The results showed that by overhead the ground floor of the first row of windward buildings and appropriately increasing the wind direction angle, the outdoor average wind speed was increased by 0.7 m/s, which had a good improvement on the wind environment of the residential zone and building energy consumption, and also verified the feasibility and importance of CFD simulation in architectural planning and design.
In order to study the wind environment problems in the old community, taking the residential zone of Henan University of Science and Technology in Luoyang City, Henan Province, as the research object, taking the original meteorological data of Zhengzhou City as the data source, substituting it into Phoenics as a boundary condition to simulate the wind environment, and combining the relevant technical standards of green buildings to analyze the wind speed and wind pressure of the dominant wind in July. Some improvement measures for the existing wind environment problems in the campus were provided, and the wind environment was simulated again after the improvement. The results showed that by overhead the ground floor of the first row of windward buildings and appropriately increasing the wind direction angle, the outdoor average wind speed was increased by 0.7 m/s, which had a good improvement on the wind environment of the residential zone and building energy consumption, and also verified the feasibility and importance of CFD simulation in architectural planning and design.
2024, 54(3): 97-109.
doi: 10.3724/j.gyjzG22102703
Abstract:
At present, there are a series of problems in the design and construction of rural buildings in China, such as lack of construction standards, uncontrollable building quality, and low degree of construction industrialization. In the direction of new construction industrialization, it is an effective way to solve the above problems by adopting the mode of building productization design and construction. In this mode, constructing an industrialized rural building product design system and implementation path, establishing a productization design method for industrialized rural buildings including products platform design method and rural building product design process and three-level component combination design method based on component library. At last, a construction management technology including three-level component nesting modeling technology, component spatial position coding technology, and component lifecycle construction management technology was developed. The above technologies and methods were verified in the research, productization design practice of industrial rural buildings represented by "Dream House" and "Kongjia Village Service Center". The design system, design method and construction management technology could effectively improve the design and construction level of rural buildings , as well as the quality of rural buildings, also could promote the development of the rural building industry.
At present, there are a series of problems in the design and construction of rural buildings in China, such as lack of construction standards, uncontrollable building quality, and low degree of construction industrialization. In the direction of new construction industrialization, it is an effective way to solve the above problems by adopting the mode of building productization design and construction. In this mode, constructing an industrialized rural building product design system and implementation path, establishing a productization design method for industrialized rural buildings including products platform design method and rural building product design process and three-level component combination design method based on component library. At last, a construction management technology including three-level component nesting modeling technology, component spatial position coding technology, and component lifecycle construction management technology was developed. The above technologies and methods were verified in the research, productization design practice of industrial rural buildings represented by "Dream House" and "Kongjia Village Service Center". The design system, design method and construction management technology could effectively improve the design and construction level of rural buildings , as well as the quality of rural buildings, also could promote the development of the rural building industry.
2024, 54(3): 110-117.
doi: 10.3724/j.gyjzG23030201
Abstract:
Fiber cement board as the bottom formwork of steel truss deck is a new type of steel bars truss deck. In order to ensure the construction safety of steel bars truss deck with cement fiber board bottom formworks and provide a basis for revising the Code for Design and Construction of Composite Slabs (CECS 273︰ 2010), the bearing capacity of 36 long specimens and 36 short specimens of the steel bars truss decks with fiber cement board bottom formworks was tested. The results showed that the nail cap pulling failure, bottom formwork edge failure, and fastener failure would occur at the lateral edges of bottom formworks under the action of concentrated line load. Based on the analysis of experimental phenomena and data, the paper proposed theoretical and practical calculation formulas for nail cap pull-out failure and bottom formwork edge failure, and also provided standard test methods for the bearing capacity of connectors. The theoretical calculation formula given in the paper agreed well with the test results, while the results obtained by practical formula were conservative.
Fiber cement board as the bottom formwork of steel truss deck is a new type of steel bars truss deck. In order to ensure the construction safety of steel bars truss deck with cement fiber board bottom formworks and provide a basis for revising the Code for Design and Construction of Composite Slabs (CECS 273︰ 2010), the bearing capacity of 36 long specimens and 36 short specimens of the steel bars truss decks with fiber cement board bottom formworks was tested. The results showed that the nail cap pulling failure, bottom formwork edge failure, and fastener failure would occur at the lateral edges of bottom formworks under the action of concentrated line load. Based on the analysis of experimental phenomena and data, the paper proposed theoretical and practical calculation formulas for nail cap pull-out failure and bottom formwork edge failure, and also provided standard test methods for the bearing capacity of connectors. The theoretical calculation formula given in the paper agreed well with the test results, while the results obtained by practical formula were conservative.
2024, 54(3): 118-125.
doi: 10.3724/j.gyjzG23061405
Abstract:
A dynamic performance test was conducted on a magnetorheological damping self-centering brace (MR-SCB) that can provide both Coulomb damping and viscous damping simultaneously. The results showed that the brace exhibited a full flag-shaped hysteretic curve, with excellent recentering and energy dissipation capabilities. Its energy dissipation in half-cycle did not change significantly with the change of the pre-pressed force and stiffness of disc spring group. The ultimate bearing capacity increased with the increase of the pre-pressed force and stiffness, while the residual displacement decreased with the increase of pre-pressed force. When the loading frequency and displacement were 0.7 Hz and 22 mm, respectively, the equivalent viscous damping ratio and residual displacement of brace were 0.215 and 5.3 mm, respectively, increasing by 14.4% and 61.1% compared with those under 0.3 Hz excitation. A nonlinear simulation analysis was conducted on a steel frame structure with MR-SCBs, and it was found that compared with traditional self-centering braces, MR-SCB dissipated more input seismic energy, achieving better control effect on the displacement of frame. Under rarely occurred earthquakes, the statistical dispersion of residual displacement response was lower, and the maximum result was reduced from 0.061% to 0.049%. The interstory drift and residual displacement of the structure decreased with the increase of proportion of viscous damping force of braces.
A dynamic performance test was conducted on a magnetorheological damping self-centering brace (MR-SCB) that can provide both Coulomb damping and viscous damping simultaneously. The results showed that the brace exhibited a full flag-shaped hysteretic curve, with excellent recentering and energy dissipation capabilities. Its energy dissipation in half-cycle did not change significantly with the change of the pre-pressed force and stiffness of disc spring group. The ultimate bearing capacity increased with the increase of the pre-pressed force and stiffness, while the residual displacement decreased with the increase of pre-pressed force. When the loading frequency and displacement were 0.7 Hz and 22 mm, respectively, the equivalent viscous damping ratio and residual displacement of brace were 0.215 and 5.3 mm, respectively, increasing by 14.4% and 61.1% compared with those under 0.3 Hz excitation. A nonlinear simulation analysis was conducted on a steel frame structure with MR-SCBs, and it was found that compared with traditional self-centering braces, MR-SCB dissipated more input seismic energy, achieving better control effect on the displacement of frame. Under rarely occurred earthquakes, the statistical dispersion of residual displacement response was lower, and the maximum result was reduced from 0.061% to 0.049%. The interstory drift and residual displacement of the structure decreased with the increase of proportion of viscous damping force of braces.
2024, 54(3): 126-132.
doi: 10.3724/j.gyjzG23030303
Abstract:
A crack detection method based on hierarchical residual neural network is proposed to improve the automation of the crack detection task for underwater structures of bridges. The method utilizes a multi-level feature residual linkage mechanism, which suppresses the interference of noise features on the building surface, extracts and fuses feature images at different levels, and enhances the model's capacity to accurately delineate cracked and non-cracked regions. Meanwhile, with the help of transfer learning method, the model is initialized with the parameters of the pre-trained model and the weights are adjusted with the underwater crack dataset, so that the model has the capacity to analyze the bridge underwater structure crack dataset with very small amount of data. The model was experimentally validated on a self-collected bridge underwater structural crack dataset. The results showed that the hierarchical residual neural network could accurately classify cracked pixels from non-cracked pixels, and the predicted pixel accuracy reached 87.2%, which proved the feasibility of the method. The model provides an effective solution for automating the bridge underwater structural crack detection task, and also provides a reference idea for other similar image detection tasks.
A crack detection method based on hierarchical residual neural network is proposed to improve the automation of the crack detection task for underwater structures of bridges. The method utilizes a multi-level feature residual linkage mechanism, which suppresses the interference of noise features on the building surface, extracts and fuses feature images at different levels, and enhances the model's capacity to accurately delineate cracked and non-cracked regions. Meanwhile, with the help of transfer learning method, the model is initialized with the parameters of the pre-trained model and the weights are adjusted with the underwater crack dataset, so that the model has the capacity to analyze the bridge underwater structure crack dataset with very small amount of data. The model was experimentally validated on a self-collected bridge underwater structural crack dataset. The results showed that the hierarchical residual neural network could accurately classify cracked pixels from non-cracked pixels, and the predicted pixel accuracy reached 87.2%, which proved the feasibility of the method. The model provides an effective solution for automating the bridge underwater structural crack detection task, and also provides a reference idea for other similar image detection tasks.
2024, 54(3): 133-142.
doi: 10.13204/j.gyjzG22111310
Abstract:
The damage index can quantify the damage degree of structures and components under earthquake, and provide an important theoretical basis for the post-seismic damage assessment and design of structures. For this reason, this paper conducted on the experiments of seismic performance and cumulative damage analysis about 15 concrete columns confined by high-strength stirrups. The test results showed that the stirrup did not yield at the peak point and the tensile stress of stirrup was 56%–91% of the yield strength. The stirrup could yield at the ultimate displacement but did not break. The concrete columns confined by high-strength stirrups showed good bearing capacity and deformation capacity in the whole loading process. For concrete columns confined by high-strength stirrups whose concrete grade is C50 and longitudinal reinforcement strength grade is HRB500, the comparison between calculated results of different damage models and test results showed that the Chai model could accurately predict the damage degree. For specimens with a shear-span ratio of 3, larger reinforcement ratio and stirrup ratio, the damage index calculated by Kunnath model was slightly smaller at the stage of minor damage and moderate failure. The Fu model could predict the damage degree of confined concrete columns at five stages, but the calculated values were greater than 1 and did not converge. Confined concrete columns with larger shearspan ratio would decrease the development rate of damage, and the increase in axial compression ratio would aggravate the damage degree of confined concrete columns. With high reinforcement ratio and stirrup ratio, the damage development rate was slower and the damage degree was relatively lower with the same cyclic times. In the stirrup design of confined concrete columns, the cumulative damage can be decreased and delayed based on a rational configuration of longitudinal rebar sand stirrups.
The damage index can quantify the damage degree of structures and components under earthquake, and provide an important theoretical basis for the post-seismic damage assessment and design of structures. For this reason, this paper conducted on the experiments of seismic performance and cumulative damage analysis about 15 concrete columns confined by high-strength stirrups. The test results showed that the stirrup did not yield at the peak point and the tensile stress of stirrup was 56%–91% of the yield strength. The stirrup could yield at the ultimate displacement but did not break. The concrete columns confined by high-strength stirrups showed good bearing capacity and deformation capacity in the whole loading process. For concrete columns confined by high-strength stirrups whose concrete grade is C50 and longitudinal reinforcement strength grade is HRB500, the comparison between calculated results of different damage models and test results showed that the Chai model could accurately predict the damage degree. For specimens with a shear-span ratio of 3, larger reinforcement ratio and stirrup ratio, the damage index calculated by Kunnath model was slightly smaller at the stage of minor damage and moderate failure. The Fu model could predict the damage degree of confined concrete columns at five stages, but the calculated values were greater than 1 and did not converge. Confined concrete columns with larger shearspan ratio would decrease the development rate of damage, and the increase in axial compression ratio would aggravate the damage degree of confined concrete columns. With high reinforcement ratio and stirrup ratio, the damage development rate was slower and the damage degree was relatively lower with the same cyclic times. In the stirrup design of confined concrete columns, the cumulative damage can be decreased and delayed based on a rational configuration of longitudinal rebar sand stirrups.
2024, 54(3): 143-152.
doi: 10.13204/j.gyjzG21092803
Abstract:
Shaped steel embedded UHPC (ultra-high-performance concrete) has obvious advantages over shaped steel embedded normal concrete in bond strength and deformation performance. The bond-slip relation of shaped steel embedded UHPC shows unique slip pseudo-plasticity, but the constitutive model characterizing the bond slip has not been reported. Based on the published test data, the formula to predict the characteristic bond strength and slip was developed by using the key parameters of grey correlation and a new bond stress-slip constitutive models for steel-UHPC was proposed. This study also verified the model accuracy against the published test data. Based on that, the finite element (FE) model was established to analyze the development of interface slip by using the cohesive zone model to simulate the bond-slip properties between H-shaped steel and UHPC. The comparison between the FE analysis and the test results showed that the proposed cohesive zone model could accurately simulate the slip and damage development of the shaped steel-UHPC interface.
Shaped steel embedded UHPC (ultra-high-performance concrete) has obvious advantages over shaped steel embedded normal concrete in bond strength and deformation performance. The bond-slip relation of shaped steel embedded UHPC shows unique slip pseudo-plasticity, but the constitutive model characterizing the bond slip has not been reported. Based on the published test data, the formula to predict the characteristic bond strength and slip was developed by using the key parameters of grey correlation and a new bond stress-slip constitutive models for steel-UHPC was proposed. This study also verified the model accuracy against the published test data. Based on that, the finite element (FE) model was established to analyze the development of interface slip by using the cohesive zone model to simulate the bond-slip properties between H-shaped steel and UHPC. The comparison between the FE analysis and the test results showed that the proposed cohesive zone model could accurately simulate the slip and damage development of the shaped steel-UHPC interface.
2024, 54(3): 153-160.
doi: 10.13204/j.gyjzG22051009
Abstract:
Eight UHPC-RC (ultra-high performance concrete-reinforced concrete) composite columns (including two RC contrast columns) were fabricated by using ultra-high performance concrete (UHPC) to replace certain thickness of ordinary concrete on the tensile zone of reinforced concrete (RC) columns. The influence of eccentricity, UHPC layer thickness and UHPC layers with or without steel bars on cracking performance, ultimate bearing capacity and ductility of composite columns was studied. The results showed that UHPC layers significantly improved the crack resistance of RC columns, delayed the occurrence of cracks to different degrees, and presented the typical multi-cracks on the tensile side of UHPC-RC composite columns. The ultimate bearing capacity and ductility of UHPC-RC composite columns were improved to various extends, with the increase of UHPC layer thickness and combination of UHPC layers and steel reinforcing bars (R-UHPC). The formula of calculating the ultimate bearing capacity of UHPC-RC composite columns was proposed, and it showed a good agreement between the calculated values and the experimental results.
Eight UHPC-RC (ultra-high performance concrete-reinforced concrete) composite columns (including two RC contrast columns) were fabricated by using ultra-high performance concrete (UHPC) to replace certain thickness of ordinary concrete on the tensile zone of reinforced concrete (RC) columns. The influence of eccentricity, UHPC layer thickness and UHPC layers with or without steel bars on cracking performance, ultimate bearing capacity and ductility of composite columns was studied. The results showed that UHPC layers significantly improved the crack resistance of RC columns, delayed the occurrence of cracks to different degrees, and presented the typical multi-cracks on the tensile side of UHPC-RC composite columns. The ultimate bearing capacity and ductility of UHPC-RC composite columns were improved to various extends, with the increase of UHPC layer thickness and combination of UHPC layers and steel reinforcing bars (R-UHPC). The formula of calculating the ultimate bearing capacity of UHPC-RC composite columns was proposed, and it showed a good agreement between the calculated values and the experimental results.
2024, 54(3): 161-166.
doi: 10.13204/j.gyjzG21061009
Abstract:
Based on the current studies of various composite bridge decks, a novel composite deck with large-scale corrugated steel plate and ultra-high performance concrete (UHPC) layer is proposed. The fatigue property of the composite deck will be enhanced by increasing rigidity through the high-performance of UHPC and decreasing weld joints through large-scale corrugated steel plate. With the fatigue studies of the novel composite decks, it can be found that the increase of the UHPC thickness and the decrease of the diaphragm distance will reduce the fatigue stress amplitude of all fatigue details, so a UHPC thickness of 70–90 cm and a spacing of less than 4 cm between diaphragms are recommended. The increase of the U-rib height will also reduce the stress amplitude of almost all fatigue details, except the fatigue detail between the web of the U-rib and the diaphragm. Meanwhile, the UHPC thickness and the reinforcement ratio are the critical factors of the fatigue property of the UHPC layer. For the UHPC layer with the thickness less than 9 cm, the limitation of the minimum reinforcement ratio will ensure the fatigue property of the UHPC layer.
Based on the current studies of various composite bridge decks, a novel composite deck with large-scale corrugated steel plate and ultra-high performance concrete (UHPC) layer is proposed. The fatigue property of the composite deck will be enhanced by increasing rigidity through the high-performance of UHPC and decreasing weld joints through large-scale corrugated steel plate. With the fatigue studies of the novel composite decks, it can be found that the increase of the UHPC thickness and the decrease of the diaphragm distance will reduce the fatigue stress amplitude of all fatigue details, so a UHPC thickness of 70–90 cm and a spacing of less than 4 cm between diaphragms are recommended. The increase of the U-rib height will also reduce the stress amplitude of almost all fatigue details, except the fatigue detail between the web of the U-rib and the diaphragm. Meanwhile, the UHPC thickness and the reinforcement ratio are the critical factors of the fatigue property of the UHPC layer. For the UHPC layer with the thickness less than 9 cm, the limitation of the minimum reinforcement ratio will ensure the fatigue property of the UHPC layer.
2024, 54(3): 167-173.
doi: 10.3724/j.gyjzG22062701
Abstract:
To explore the microscopic mechanisms of the macroscopic shear responses of dense-mixed soil with different contents of fine particles affected by initial stress ratios, the discrete element method was used to study the macroscopic and microscopic shear responses of mixed soil. Mixed soil consisted of spherical fine particles and coarse particles with real gravel shapes. Research indicated that an increase in initial stress ratios could increase both friction and dilatancy angles at initial loading stages. It was found that initial stress ratios had little influence on engineering classifications of mixed soil by analyzing the contact contributions of coarse-coarse, coarse-fine, and fine-fine particles. With increase in initial stress ratios, the shear strength of mixed soil increased at initial loading stages, which was closely related to an increase in contact forces particles. With increase in initial stress ratios, the increase in internal fiction angles at initial loading stages could be attributed to the anisotropic increase degree of contact, normal contact force, normal and tangential branch vectors beyond the anisotropic decrease degree of tangential contact force.
To explore the microscopic mechanisms of the macroscopic shear responses of dense-mixed soil with different contents of fine particles affected by initial stress ratios, the discrete element method was used to study the macroscopic and microscopic shear responses of mixed soil. Mixed soil consisted of spherical fine particles and coarse particles with real gravel shapes. Research indicated that an increase in initial stress ratios could increase both friction and dilatancy angles at initial loading stages. It was found that initial stress ratios had little influence on engineering classifications of mixed soil by analyzing the contact contributions of coarse-coarse, coarse-fine, and fine-fine particles. With increase in initial stress ratios, the shear strength of mixed soil increased at initial loading stages, which was closely related to an increase in contact forces particles. With increase in initial stress ratios, the increase in internal fiction angles at initial loading stages could be attributed to the anisotropic increase degree of contact, normal contact force, normal and tangential branch vectors beyond the anisotropic decrease degree of tangential contact force.
2024, 54(3): 174-181.
doi: 10.3724/j.gyjzG22082708
Abstract:
The rock content in freezing-thawing cycles is one of the key factors influencing the hydro-thermal transfer and freezing-thaw transferring characteristics of soil-rock mixtures. To study the effect of freezing-thawing cycles on hydro-thermal transfer, frost heave and thawing settlement of soil-rock mixtures, the soil-rock mixtures composed by Qinghai-Tibet silty clay and gravel with different stone content ratios (10%, 25%, 40%) were selected as research objects, and 10 unidirectional freezing-thawing cycles were conducted. The results indicated that the differences in the temperature and unfrozen water content of soil-rock mixtures during the freezing-thaw cycles had a strong correlation with the rock content. With an increase in the rock content, the completely frozen time for soil-rock mixtures has been extended, and the variable rate of the unfrozen wate content decreased. The difference of buried depth mainly influenced the temperature transfer of soil-rock mixture, and had an indirect effect on the variation of volumetric unfrozen water. For the samples with stone contents of 10% and 40%, the displacement change was manifested as shrinkage during freezing and expansion after thawing, and with an increase in the stone content, the shrinkage of specimens during freezing tended to decrease.
The rock content in freezing-thawing cycles is one of the key factors influencing the hydro-thermal transfer and freezing-thaw transferring characteristics of soil-rock mixtures. To study the effect of freezing-thawing cycles on hydro-thermal transfer, frost heave and thawing settlement of soil-rock mixtures, the soil-rock mixtures composed by Qinghai-Tibet silty clay and gravel with different stone content ratios (10%, 25%, 40%) were selected as research objects, and 10 unidirectional freezing-thawing cycles were conducted. The results indicated that the differences in the temperature and unfrozen water content of soil-rock mixtures during the freezing-thaw cycles had a strong correlation with the rock content. With an increase in the rock content, the completely frozen time for soil-rock mixtures has been extended, and the variable rate of the unfrozen wate content decreased. The difference of buried depth mainly influenced the temperature transfer of soil-rock mixture, and had an indirect effect on the variation of volumetric unfrozen water. For the samples with stone contents of 10% and 40%, the displacement change was manifested as shrinkage during freezing and expansion after thawing, and with an increase in the stone content, the shrinkage of specimens during freezing tended to decrease.
2024, 54(3): 182-190.
doi: 10.3724/j.gyjzG22090209
Abstract:
By studying the variations of bearing capacity characteristics of two bored piles before and after being grouted, the radius of the plastic influential zone of cement pastes after being compactedly grouted at pile ends was derived by Vesic’ s theory. A single pile model and pile group models considering different quantities of piles, pile spacing, and grouting conditions were respectively constructed, in which the pile spacing was 2 to 6-times pile diameters for 2×2 pile groups and 3-times pile diameters for 3×3 pile groups. Then, the effect of grouting at pile ends on settlement, pile end resistance, pile side resistance, and ratios of pile end resistance and total resistance were studied. The conclusions were that the grouting bearing capacity efficiency for pile group foundations dropped with an increase in pile quantities in the same pile space. The order of the bearing capacity of 2×2 pile group foundations from large to small was the foundation with pile space of 5-, 6-, 4-, and 3-times pile diameters. When the pile spacing was 5-times pile diameters, the bonding effect of expanding heads of pile ends and pile group effect were maximized. In the same working condition, the ratio of end resistance and total resistance was significantly enhanced after being grouted, while in the same quantity of piles, the ratio of end resistance and total resistance dropped gradually with an increase in pile space. When the pile space was smaller, the end resistance of piles increased more apparently than the side friction resistance of piles. As the ferrule effect by side piles, corner piles and surrounding soil on middle piles in settlement processes of pile foundations, lateral friction resistance of corner piles and side piles worked earlier than that of middle piles. The order of lateral friction resistance from large to small was that of corner piles, side piles and middle piles.
By studying the variations of bearing capacity characteristics of two bored piles before and after being grouted, the radius of the plastic influential zone of cement pastes after being compactedly grouted at pile ends was derived by Vesic’ s theory. A single pile model and pile group models considering different quantities of piles, pile spacing, and grouting conditions were respectively constructed, in which the pile spacing was 2 to 6-times pile diameters for 2×2 pile groups and 3-times pile diameters for 3×3 pile groups. Then, the effect of grouting at pile ends on settlement, pile end resistance, pile side resistance, and ratios of pile end resistance and total resistance were studied. The conclusions were that the grouting bearing capacity efficiency for pile group foundations dropped with an increase in pile quantities in the same pile space. The order of the bearing capacity of 2×2 pile group foundations from large to small was the foundation with pile space of 5-, 6-, 4-, and 3-times pile diameters. When the pile spacing was 5-times pile diameters, the bonding effect of expanding heads of pile ends and pile group effect were maximized. In the same working condition, the ratio of end resistance and total resistance was significantly enhanced after being grouted, while in the same quantity of piles, the ratio of end resistance and total resistance dropped gradually with an increase in pile space. When the pile space was smaller, the end resistance of piles increased more apparently than the side friction resistance of piles. As the ferrule effect by side piles, corner piles and surrounding soil on middle piles in settlement processes of pile foundations, lateral friction resistance of corner piles and side piles worked earlier than that of middle piles. The order of lateral friction resistance from large to small was that of corner piles, side piles and middle piles.
2024, 54(3): 191-199.
doi: 10.3724/j.gyjzG23033014
Abstract:
Pile foundations are the most commonly used foundation forms of terrestrial photovoltaic supports, which mainly bear horizontal loads. The analysis method for horizontal bearing characteristics of pile foundations normally in use at present is the p-y curve method recommended by American Petroleum Institute (API). To research the applicability of the p-y curve method recommended in calculating deformation of small-diameter rigid piles acted by horizontal loads, a three-dimensional finite element numerical model of small-diameter rigid piles with four different pile diameters was constructed based on a photovoltaic project. The horizontal bearing characteristics were analyzed and the p-y curves of pile foundations at different depths were obtained. On that basis, a modified p-y curve calculation model of small and medium diameter single piles in sandy soil was proposed considering pile diameters and depths. The results indicated that the horizontal displacement of small diameter rigid piles was inversely proportional to pile diameters, and the influence of pile diameters on pile bending moment was not significant. Compared with numerical simulations, the initial stiffness calculated by the p-y curve recommended by API was larger and the ultimate soil resistance was smaller, the p-y curre method recommended by API was not suitable for calculations of small-diameter rigid piles under horizontal loads. Based on the numerical simulation results, the relation equations among pile diameters, depth and initial foundation stiffness or ultimate soil resistance were fitted, and a modified model of the p-y curve was established. The modified model was verified that agreed fairly well with the actual values.
Pile foundations are the most commonly used foundation forms of terrestrial photovoltaic supports, which mainly bear horizontal loads. The analysis method for horizontal bearing characteristics of pile foundations normally in use at present is the p-y curve method recommended by American Petroleum Institute (API). To research the applicability of the p-y curve method recommended in calculating deformation of small-diameter rigid piles acted by horizontal loads, a three-dimensional finite element numerical model of small-diameter rigid piles with four different pile diameters was constructed based on a photovoltaic project. The horizontal bearing characteristics were analyzed and the p-y curves of pile foundations at different depths were obtained. On that basis, a modified p-y curve calculation model of small and medium diameter single piles in sandy soil was proposed considering pile diameters and depths. The results indicated that the horizontal displacement of small diameter rigid piles was inversely proportional to pile diameters, and the influence of pile diameters on pile bending moment was not significant. Compared with numerical simulations, the initial stiffness calculated by the p-y curve recommended by API was larger and the ultimate soil resistance was smaller, the p-y curre method recommended by API was not suitable for calculations of small-diameter rigid piles under horizontal loads. Based on the numerical simulation results, the relation equations among pile diameters, depth and initial foundation stiffness or ultimate soil resistance were fitted, and a modified model of the p-y curve was established. The modified model was verified that agreed fairly well with the actual values.
2024, 54(3): 200-205.
doi: 10.3724/j.gyjzG22090804
Abstract:
In order to study the mechanical properties of the interface between anchor bolts and soil, the pull-out tests on indoor anchor bolts were performed. The effects of confining pressure, water content and soil strength on the mechanical properties the interfaces between anchorage bodies and soil were studied taking precast and cast-in-situ anchor bolts as objects. Simultaneously, the shear properties of the two types of anchor bolts were compared, and the whole process model of shear stress-shear displacement between interfaces of anchorage bodies and soil was proposed. The results indicated that the higher the confining pressures were, the greater the shear stresses of the interfaces and the ultimate pullout forces of anchor bolts were. With the increase in the water content, the ultimate pullout forces of anchor bolts increased first and then decreased, and when the water content of soil closed its optimal water content, the anchorage properties of anchor bolts were relatively better. The higher the soil strength was the greater the ultimate pullout forces of anchor bolts were. The ultimate forces of cast-in-situ anchor bolts were greater than that of precast anchor bolts, and the differences of the ultimate pullout force between the two types of anchor bolts were greater with the increase in confining pressures. The failure modes of the two types of anchor bolts were consistent. The proposed fitting curves of stress-strain relations between interfaces of anchorage bodies and soil were fairly good agreement with the measured curves by tests.
In order to study the mechanical properties of the interface between anchor bolts and soil, the pull-out tests on indoor anchor bolts were performed. The effects of confining pressure, water content and soil strength on the mechanical properties the interfaces between anchorage bodies and soil were studied taking precast and cast-in-situ anchor bolts as objects. Simultaneously, the shear properties of the two types of anchor bolts were compared, and the whole process model of shear stress-shear displacement between interfaces of anchorage bodies and soil was proposed. The results indicated that the higher the confining pressures were, the greater the shear stresses of the interfaces and the ultimate pullout forces of anchor bolts were. With the increase in the water content, the ultimate pullout forces of anchor bolts increased first and then decreased, and when the water content of soil closed its optimal water content, the anchorage properties of anchor bolts were relatively better. The higher the soil strength was the greater the ultimate pullout forces of anchor bolts were. The ultimate forces of cast-in-situ anchor bolts were greater than that of precast anchor bolts, and the differences of the ultimate pullout force between the two types of anchor bolts were greater with the increase in confining pressures. The failure modes of the two types of anchor bolts were consistent. The proposed fitting curves of stress-strain relations between interfaces of anchorage bodies and soil were fairly good agreement with the measured curves by tests.
2024, 54(3): 206-214.
doi: 10.3724/j.gyjzG23060210
Abstract:
The good bonding performance between rebars and concrete is the basis for the normal operation of reinforced concrete members and has a significant impact on the structural performance. The incorporation of steel fibers into concrete significantly improves the crack-resistant and tensile properties of concrete, thereby effectively improving the bonding properties between rebars and concrete. The research status of bonding performance between rebars and steel fiber reinforced concrete (SFRC) was summarized, including three aspects: bonding mechanism, bonding strength, and bond-slip models. Firstly, the bonding mechanism between rebars and SFRC was elucidated through the bonding force composition, bonding failure modes and steel fiber reinforcement mechanism; secondly, the applicability of the test results of different central pull-out specimens and test devices to the design of the structure were summarized, and the bonding strength test methods and influencing factors were analyzed, in addition to the types of rebars, concrete strength, transverse reinforcement restraint and other factors, the addition of steel fibers had an important influence on the bonding performance; then, the bonding strength calculation model and bond-slip constitutive relations were summarized and analyzed, and the applicability, advantages and disadvantages of each model were compared and analyzed. Finally, some methods and measures to improve the bonding performance of reinforcement and concrete were suggested.
The good bonding performance between rebars and concrete is the basis for the normal operation of reinforced concrete members and has a significant impact on the structural performance. The incorporation of steel fibers into concrete significantly improves the crack-resistant and tensile properties of concrete, thereby effectively improving the bonding properties between rebars and concrete. The research status of bonding performance between rebars and steel fiber reinforced concrete (SFRC) was summarized, including three aspects: bonding mechanism, bonding strength, and bond-slip models. Firstly, the bonding mechanism between rebars and SFRC was elucidated through the bonding force composition, bonding failure modes and steel fiber reinforcement mechanism; secondly, the applicability of the test results of different central pull-out specimens and test devices to the design of the structure were summarized, and the bonding strength test methods and influencing factors were analyzed, in addition to the types of rebars, concrete strength, transverse reinforcement restraint and other factors, the addition of steel fibers had an important influence on the bonding performance; then, the bonding strength calculation model and bond-slip constitutive relations were summarized and analyzed, and the applicability, advantages and disadvantages of each model were compared and analyzed. Finally, some methods and measures to improve the bonding performance of reinforcement and concrete were suggested.
2024, 54(3): 215-226.
doi: 10.3724/j.gyjzG22083103
Abstract:
Duobao pagodas are common in East Asia, which are a unique part of architectural types of pagodas. Up to now, the definition on Duobao pagodas in East Asia has not been clear-cul, relevant research has not been systematic, especially the research on historical origins, development contexts and architectural styles must be supplemented. Based on sorting of historical literatures and investigations of existing remains and analysis of development and dissemination of Chinese Buddhism in East Asia, the architectureal concept of Duobao pagodas in East Asia was analyzed, and the original background of Duobao pagodas and their evolution courses were systematically sorts out. On the basis, the evolution motivation and context in China, the Korean Peninsula and Japan were explored, and the regional architectural styles of existing Duobao pagodas in East Asia affected by the different geographical and climatic conditions, political culture, customs and other factors were generalized from the aspects of structural characteristics, ideological concepts, aesthetic styles, and plastic arts, and their cultural connotation and construction characteristics were unearthed.
Duobao pagodas are common in East Asia, which are a unique part of architectural types of pagodas. Up to now, the definition on Duobao pagodas in East Asia has not been clear-cul, relevant research has not been systematic, especially the research on historical origins, development contexts and architectural styles must be supplemented. Based on sorting of historical literatures and investigations of existing remains and analysis of development and dissemination of Chinese Buddhism in East Asia, the architectureal concept of Duobao pagodas in East Asia was analyzed, and the original background of Duobao pagodas and their evolution courses were systematically sorts out. On the basis, the evolution motivation and context in China, the Korean Peninsula and Japan were explored, and the regional architectural styles of existing Duobao pagodas in East Asia affected by the different geographical and climatic conditions, political culture, customs and other factors were generalized from the aspects of structural characteristics, ideological concepts, aesthetic styles, and plastic arts, and their cultural connotation and construction characteristics were unearthed.
2024, 54(3): 227-236.
doi: 10.3724/j.gyjzG23062506
Abstract:
In order to study the flexural performance of reinforced concrete beams strengthened with high-strength polyurethane composites (HSPUC), the static failure tests of two reinforced concrete beams strengthened by HSPUC reinforcement layer with different strengthening areas at the bottom of the beams and one comparative reinforced concrete beam were carried out, and the failure modes, bearing capacity, crack characteristics, deformation and strain development laws, and interface slip of the test beams were investigated. A refined numerical model was constructed through the finite element program ABAQUS to simulate the flexural performance of reinforced concrete beams strengthened with HSPUC, and the effects of flexural strength and thickness of reinforcement layer on the flexural performance were analyzed. The results showed that the test beams strengthened by HSPUC in non-full length range and full length range of the bottom of the beam experienced debonding failure of the protective layer at the beam end and plastic flexural failure, respectively. Their ultimate bearing capacity increased by 30.4% and 79.4% compared to the unreinforced test beam, respectively. The HSPUC reinforcement method made full use of the high-strength mechanical properties of HSPUC, which could delay the occurrence and development of cracks and therefore effectively inhibit the stiffness decrease caused by crack propagation, significantly improving the flexural stiffness and ultimate bearing capacity of reinforced concrete beams. The reliable bonding strength and good cooperative working performance between the HSPUS layer and the reinforced concrete beam were observed. The mid-span load-deflection curves calculated by the numerical model were in good agreement with the experimental curves, so the numerical model can be used to calculate and analyze the entire flexural process of reinforced concrete beams strengthened with HSPUC.
In order to study the flexural performance of reinforced concrete beams strengthened with high-strength polyurethane composites (HSPUC), the static failure tests of two reinforced concrete beams strengthened by HSPUC reinforcement layer with different strengthening areas at the bottom of the beams and one comparative reinforced concrete beam were carried out, and the failure modes, bearing capacity, crack characteristics, deformation and strain development laws, and interface slip of the test beams were investigated. A refined numerical model was constructed through the finite element program ABAQUS to simulate the flexural performance of reinforced concrete beams strengthened with HSPUC, and the effects of flexural strength and thickness of reinforcement layer on the flexural performance were analyzed. The results showed that the test beams strengthened by HSPUC in non-full length range and full length range of the bottom of the beam experienced debonding failure of the protective layer at the beam end and plastic flexural failure, respectively. Their ultimate bearing capacity increased by 30.4% and 79.4% compared to the unreinforced test beam, respectively. The HSPUC reinforcement method made full use of the high-strength mechanical properties of HSPUC, which could delay the occurrence and development of cracks and therefore effectively inhibit the stiffness decrease caused by crack propagation, significantly improving the flexural stiffness and ultimate bearing capacity of reinforced concrete beams. The reliable bonding strength and good cooperative working performance between the HSPUS layer and the reinforced concrete beam were observed. The mid-span load-deflection curves calculated by the numerical model were in good agreement with the experimental curves, so the numerical model can be used to calculate and analyze the entire flexural process of reinforced concrete beams strengthened with HSPUC.
2024, 54(3): 237-245.
doi: 10.13204/j.gyjzG22050603
Abstract:
The structural safety of the boiler steel frame of a cast iron plant that has been used for more than ten years was tested, and the frequently and rarely occurred earthquakes under the seismic fortification target were calculated. Five common natural seismic waves were two artificial waves, as well as seven long-period seismic waves of far-field harmonic seismic waves and near-fault pulse seismic waves were selected. Based on the interlayer displacement angle, the deformation characteristics and seismic performance of the structure were analyzed. According to the calculation results, the reinforcement design scheme of the existing structure was proposed, and the seismic calculation of the structure after reinforcement was carried out again. The analysis results after reinforcement showed that the far-field harmonic-like seismic wave had the largest response to the structure, and the ordinary seismic wave had the smallest response. The maximum inter-story drift angles under frequently occurred earthquakes were all less than the limit value of 1/250 in Code for Seismic Design of Buildings (GB 50011—2010); the interlayer displacement angles under rarely occurred earthquakes were all less than 1/50; the maximum value of the average interlayer displacement angle of the structure appeared at the bottom, was 1/88, which was 29.5% lower than that of the original structure. The reinforcement design scheme could meet the requiremerts of GB 50011—2010, and realize the seismic fortification goal of‘no damage under frequently occurred earthquakes and no collapse under rarely occurred earthquakes’.
The structural safety of the boiler steel frame of a cast iron plant that has been used for more than ten years was tested, and the frequently and rarely occurred earthquakes under the seismic fortification target were calculated. Five common natural seismic waves were two artificial waves, as well as seven long-period seismic waves of far-field harmonic seismic waves and near-fault pulse seismic waves were selected. Based on the interlayer displacement angle, the deformation characteristics and seismic performance of the structure were analyzed. According to the calculation results, the reinforcement design scheme of the existing structure was proposed, and the seismic calculation of the structure after reinforcement was carried out again. The analysis results after reinforcement showed that the far-field harmonic-like seismic wave had the largest response to the structure, and the ordinary seismic wave had the smallest response. The maximum inter-story drift angles under frequently occurred earthquakes were all less than the limit value of 1/250 in Code for Seismic Design of Buildings (GB 50011—2010); the interlayer displacement angles under rarely occurred earthquakes were all less than 1/50; the maximum value of the average interlayer displacement angle of the structure appeared at the bottom, was 1/88, which was 29.5% lower than that of the original structure. The reinforcement design scheme could meet the requiremerts of GB 50011—2010, and realize the seismic fortification goal of‘no damage under frequently occurred earthquakes and no collapse under rarely occurred earthquakes’.
2024, 54(3): 246-251.
doi: 10.3724/j.gyjzG23122201
Abstract:
The new mode of higher education has demoned more for university campus planning and construction. The planning of Huaimi Medical Center's new campus represents a further exploration of future campus planning modes. In addition to fully meeting the basic functional needs of universities, the new campus planning adheres to the "small block and dense road network" mode of the new urban road layout, as well as the open campus planning and design concept of city-school integration. The planning cleverly combines the spatial order and architectural form guided by traditional building layout and the concept of faculty system with modem campus planning. The new ideas in design concepts, planning layout, special design, and green campus evaluation are introduced, then a magnificent and elegant medicine temple is presented. The exploration of the new campus planning mode deepens the understanding of university construction in the new era and provides experiential references and technical supports for future campus planning and design
The new mode of higher education has demoned more for university campus planning and construction. The planning of Huaimi Medical Center's new campus represents a further exploration of future campus planning modes. In addition to fully meeting the basic functional needs of universities, the new campus planning adheres to the "small block and dense road network" mode of the new urban road layout, as well as the open campus planning and design concept of city-school integration. The planning cleverly combines the spatial order and architectural form guided by traditional building layout and the concept of faculty system with modem campus planning. The new ideas in design concepts, planning layout, special design, and green campus evaluation are introduced, then a magnificent and elegant medicine temple is presented. The exploration of the new campus planning mode deepens the understanding of university construction in the new era and provides experiential references and technical supports for future campus planning and design
