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2014 Vol. 44, No. 04
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2014, 44(04): 1-6.
Abstract:
A three-dimensional finite element analysis model for elliptical concrete-filled steel tubular long columns subjected to axial compression is developed and the corresponding tests are carried out． The predicted relationship curves of load versus deflection in the middle column height and damage modes are in good agreement with the measured results． The finite element analysis model is thus used to investigate the stress and strain distribution of each component and the interaction between the steel tube and the core concrete in the whole loading process． And then，the main parameters influencing the relationship curves of load versus deflection in the middle column height such as slenderness ratio，material strength，steel tube wall thickness and cross sectional dimension are investigated． The results show the typical failure modes of these columns were the lateral overall bending at about mid-height，the slenderness ratio have obvious effects on their mechanical behavior，while the yield strength of steel tube has slight effect on their mechanical behavior．
A three-dimensional finite element analysis model for elliptical concrete-filled steel tubular long columns subjected to axial compression is developed and the corresponding tests are carried out． The predicted relationship curves of load versus deflection in the middle column height and damage modes are in good agreement with the measured results． The finite element analysis model is thus used to investigate the stress and strain distribution of each component and the interaction between the steel tube and the core concrete in the whole loading process． And then，the main parameters influencing the relationship curves of load versus deflection in the middle column height such as slenderness ratio，material strength，steel tube wall thickness and cross sectional dimension are investigated． The results show the typical failure modes of these columns were the lateral overall bending at about mid-height，the slenderness ratio have obvious effects on their mechanical behavior，while the yield strength of steel tube has slight effect on their mechanical behavior．
2014, 44(04): 7-11.
Abstract:
A finite element analysis model of elliptical concrete-filled steel tubular ( CFST) long columns subjected to eccentric compression is established using the finite element analysis software ABAQUS and the corresponding tests of 12 specimens are carried out． The results show the predicted relationship curves of load versus deflection in the middle column and damage modes are in good agreement with the measured results． The finite element analysis model is thus used to investigate the stress and strain distribution of each component and the interaction between the steel tube and the core concrete in the whole loading process． And then，the main parameters influencing the relationship curves of load versus deflection in the middle column such as slenderness ratio，material strength，steel tube wall thickness and eccentric distance are investigated． The results show the typical failure modes of these columns were the lateral overall bending at about mid-height，the slenderness ratio，the compressive strength of concrete，the steel tube wall thickness and the load eccentricity have obvious effects on their mechanical behavior，while the yield strength of steel tube has slight effect on their mechanical behavior．
A finite element analysis model of elliptical concrete-filled steel tubular ( CFST) long columns subjected to eccentric compression is established using the finite element analysis software ABAQUS and the corresponding tests of 12 specimens are carried out． The results show the predicted relationship curves of load versus deflection in the middle column and damage modes are in good agreement with the measured results． The finite element analysis model is thus used to investigate the stress and strain distribution of each component and the interaction between the steel tube and the core concrete in the whole loading process． And then，the main parameters influencing the relationship curves of load versus deflection in the middle column such as slenderness ratio，material strength，steel tube wall thickness and eccentric distance are investigated． The results show the typical failure modes of these columns were the lateral overall bending at about mid-height，the slenderness ratio，the compressive strength of concrete，the steel tube wall thickness and the load eccentricity have obvious effects on their mechanical behavior，while the yield strength of steel tube has slight effect on their mechanical behavior．
2014, 44(04): 12-15.
Abstract:
A finite element analysis ( FEA) model for elliptical concrete-filled steel tubular member under pure bending is developed by the universal FEA software ABAQUS． The corresponding tests of 6 members under pure bending are conducted to verify the FEA model． It can be found that，in general，good agreement is obtained between the predicted and test results． The FEA model is then used to investigate the mechanism of such composite members further． The stress distribution of the steel tube and the concrete，and the interaction between the steel tube and the core concrete are analyzed． And then，the main parameters influencing the ultimate bearing capacity and the loaddeformation relationship curves under pure bending such as shear span ratio，steel tube strength，concrete strength， major axis length and minor axis length are investigated． The results show the typical failure modes of these members were the lateral overall bending at about mid-length，the yield strength of steel tube，the compressive strength of concrete，the major axis length，the minor axis length and the steel tube wall thickness have obvious effects on their mechanical behavior，while the shear span ratio has slight effect on their mechanical behavior．
A finite element analysis ( FEA) model for elliptical concrete-filled steel tubular member under pure bending is developed by the universal FEA software ABAQUS． The corresponding tests of 6 members under pure bending are conducted to verify the FEA model． It can be found that，in general，good agreement is obtained between the predicted and test results． The FEA model is then used to investigate the mechanism of such composite members further． The stress distribution of the steel tube and the concrete，and the interaction between the steel tube and the core concrete are analyzed． And then，the main parameters influencing the ultimate bearing capacity and the loaddeformation relationship curves under pure bending such as shear span ratio，steel tube strength，concrete strength， major axis length and minor axis length are investigated． The results show the typical failure modes of these members were the lateral overall bending at about mid-length，the yield strength of steel tube，the compressive strength of concrete，the major axis length，the minor axis length and the steel tube wall thickness have obvious effects on their mechanical behavior，while the shear span ratio has slight effect on their mechanical behavior．
2014, 44(04): 16-20.
Abstract:
Finite element analysis ( FEA) models for 5 kinds of special-shaped ( triangular section，fan-shaped section，D-shaped section，1 /4 circular section，semicircular section) steel tubular stub columns with the same perimeter of cross-section under axial compression are developed using the finite element analysis software ABAQUS and the corresponding tests are conducted for comparison． The predicted load versus strain relationship curves and failure modes are in good agreement with the measured results． The FEA models are then used to analyze the stress and plastic strain distribution of the steel tube during the whole loading process． And finally，the main parameters influencing the bearing capacity and deformation such as section form，steel tube wall thickness and steel tube yield strength are investigated． The results show the typical failure modes of these stub columns were the local buckling at about mid-height，the section shape，the steel tube wall thickness and the steel tube yield strength have obvious effects on their mechanical behavior．
Finite element analysis ( FEA) models for 5 kinds of special-shaped ( triangular section，fan-shaped section，D-shaped section，1 /4 circular section，semicircular section) steel tubular stub columns with the same perimeter of cross-section under axial compression are developed using the finite element analysis software ABAQUS and the corresponding tests are conducted for comparison． The predicted load versus strain relationship curves and failure modes are in good agreement with the measured results． The FEA models are then used to analyze the stress and plastic strain distribution of the steel tube during the whole loading process． And finally，the main parameters influencing the bearing capacity and deformation such as section form，steel tube wall thickness and steel tube yield strength are investigated． The results show the typical failure modes of these stub columns were the local buckling at about mid-height，the section shape，the steel tube wall thickness and the steel tube yield strength have obvious effects on their mechanical behavior．
2014, 44(04): 21-26.
Abstract:
The finite element analysis ( FEA) models for 5 special-shaped ( triangular section，fan-section，Dsection， 1 /4 circular section and semicircular section) concrete-filled steel tubular stub columns with the same perimeter of cross-section under axial compression are developed using ABAQUS software and the corresponding 6 group tests are conducted for comparison． The predicted load versus strain relationship curves and failure modes are in good agreement with the measured results． The FEA models are then used to analyze the interaction between the concrete and the steel tube during the whole loading process． And then，the main parameters influencing the bearing capacity and deformation such as section shape，steel tube wall thickness，steel tube yield strength，concrete compression strength are investigated． The results show the typical failure modes of these stub columns were the outward bulge at about mid-height，the section shape，the steel tube wall thickness and the concrete compression strength have obvious effects on their mechanical behavior，while the steel tube yield strength has slight effect on their mechanical behavior．
The finite element analysis ( FEA) models for 5 special-shaped ( triangular section，fan-section，Dsection， 1 /4 circular section and semicircular section) concrete-filled steel tubular stub columns with the same perimeter of cross-section under axial compression are developed using ABAQUS software and the corresponding 6 group tests are conducted for comparison． The predicted load versus strain relationship curves and failure modes are in good agreement with the measured results． The FEA models are then used to analyze the interaction between the concrete and the steel tube during the whole loading process． And then，the main parameters influencing the bearing capacity and deformation such as section shape，steel tube wall thickness，steel tube yield strength，concrete compression strength are investigated． The results show the typical failure modes of these stub columns were the outward bulge at about mid-height，the section shape，the steel tube wall thickness and the concrete compression strength have obvious effects on their mechanical behavior，while the steel tube yield strength has slight effect on their mechanical behavior．
2014, 44(04): 27-31.
Abstract:
A three-dimensional finite element analysis model for square tapered concrete-filled steel tubular long columns subjected to longitudinal compression is developed and the corresponding tests are conducted． The predicted relationship curves of load versus 3 /4 height deflection，bearing capacities and failure modes have good agreements with the tested results． Based on the finite element analysis，stress and strain distribution in the whole loading process is analyzed，and interaction between steel tube and concrete is put forward． The influences of the main parameters such as slenderness ratio，eccentricity，tapered angle，have been analyzed on the ultimate loads and the relationship curves of load versus 3 /4 height deflection of square tapered concrete-filled steel tubular long columns． The results show the typical failure modes of these columns were the lateral overall bending at about 3 /4 height，the slenderness ratio，the tapered angle，the load eccentricity，the compressive strength of concrete and the steel tube wall thickness have obvious effects on their mechanical behavior，while the yield strength of steel tube has sight effect on their mechanical behavior．
A three-dimensional finite element analysis model for square tapered concrete-filled steel tubular long columns subjected to longitudinal compression is developed and the corresponding tests are conducted． The predicted relationship curves of load versus 3 /4 height deflection，bearing capacities and failure modes have good agreements with the tested results． Based on the finite element analysis，stress and strain distribution in the whole loading process is analyzed，and interaction between steel tube and concrete is put forward． The influences of the main parameters such as slenderness ratio，eccentricity，tapered angle，have been analyzed on the ultimate loads and the relationship curves of load versus 3 /4 height deflection of square tapered concrete-filled steel tubular long columns． The results show the typical failure modes of these columns were the lateral overall bending at about 3 /4 height，the slenderness ratio，the tapered angle，the load eccentricity，the compressive strength of concrete and the steel tube wall thickness have obvious effects on their mechanical behavior，while the yield strength of steel tube has sight effect on their mechanical behavior．
2014, 44(04): 32-36.
Abstract:
A three-dimensional finite element analysis model for circular tapered concrete-filled steel tubular long columns subjected to longitudinal compression is developed and the corresponding tests are conducted． The predicted relationship curves of load versus 3 /4 height deflection，bearing capacities and failure modes have good agreements with the tested results． Based on the finite element analysis，stress and strain distribution in the whole loading process is analyzed，and interaction between steel tubes and concrete is put forward． In the meantime，the main parameters such as slenderness ratio，tapered angle，eccentricity，strength of the materials，steel tube wall thickness have been analyzed on the ultimate loads of circular tapered concrete-filled steel tubular long columns and the relationship curves of load versus 3 /4 height deflection． The results show the typical failure modes of these columns were the lateral overall bending at about 3 /4 height，the slenderness ratio，the tapered angle，the load eccentricity，the compressive strength of concrete and the steel tube wall thickness have obvious effects on their mechanical behavior，while the yield strength of steel tube has slight effect on their mechanical behavior．
A three-dimensional finite element analysis model for circular tapered concrete-filled steel tubular long columns subjected to longitudinal compression is developed and the corresponding tests are conducted． The predicted relationship curves of load versus 3 /4 height deflection，bearing capacities and failure modes have good agreements with the tested results． Based on the finite element analysis，stress and strain distribution in the whole loading process is analyzed，and interaction between steel tubes and concrete is put forward． In the meantime，the main parameters such as slenderness ratio，tapered angle，eccentricity，strength of the materials，steel tube wall thickness have been analyzed on the ultimate loads of circular tapered concrete-filled steel tubular long columns and the relationship curves of load versus 3 /4 height deflection． The results show the typical failure modes of these columns were the lateral overall bending at about 3 /4 height，the slenderness ratio，the tapered angle，the load eccentricity，the compressive strength of concrete and the steel tube wall thickness have obvious effects on their mechanical behavior，while the yield strength of steel tube has slight effect on their mechanical behavior．
2014, 44(04): 37-39.
Abstract:
At present，many problems exist in the construction of national mine park，such as the imbalanced regional development，the over-concentrated distribution of mineral structure，and the disconnection between the declaration and the subsequent management． In dealing with these problems，the article put forward seven suggestions to promote the sustainable development of the national mine parks construction，the seven suggestions are the following seven facets of concentration，including balance，abundance，supervision，system，protection，construction and profit．
At present，many problems exist in the construction of national mine park，such as the imbalanced regional development，the over-concentrated distribution of mineral structure，and the disconnection between the declaration and the subsequent management． In dealing with these problems，the article put forward seven suggestions to promote the sustainable development of the national mine parks construction，the seven suggestions are the following seven facets of concentration，including balance，abundance，supervision，system，protection，construction and profit．
2014, 44(04): 40-44.
Abstract:
The industrial architectural heritages are regarded as a living fossil in the history of the development of industry，construction，economy，etc． The industry adjustment of society，the special needs of urban planning and technical tast development lead to the elimination and decay of old industrial buildings． In advocating low carbon society，under the slogan of based on the protection of industrial heritage，to explore the regeneration of the old industrial architecture design method and management pattern appears to be strong not to stay，starting from the regeneration design method of industrial heritage，it was explored the management mode and development trend of industrial heritages．
The industrial architectural heritages are regarded as a living fossil in the history of the development of industry，construction，economy，etc． The industry adjustment of society，the special needs of urban planning and technical tast development lead to the elimination and decay of old industrial buildings． In advocating low carbon society，under the slogan of based on the protection of industrial heritage，to explore the regeneration of the old industrial architecture design method and management pattern appears to be strong not to stay，starting from the regeneration design method of industrial heritage，it was explored the management mode and development trend of industrial heritages．
2014, 44(04): 45-48.
Abstract:
This article puts forward the concept of the integrated conservation from the cultural attribute of industrial heritage，according to the current situation of neglecting and disregarding the wholeness in industrial heritage protecting and reusing． By taking the industry heritage conservation of Wuhan for example，it will be built up an integral conservation framework of Wuhan industrial heritage through cultural integration from the view of urban development and spatial integration from the view of cultural type．
This article puts forward the concept of the integrated conservation from the cultural attribute of industrial heritage，according to the current situation of neglecting and disregarding the wholeness in industrial heritage protecting and reusing． By taking the industry heritage conservation of Wuhan for example，it will be built up an integral conservation framework of Wuhan industrial heritage through cultural integration from the view of urban development and spatial integration from the view of cultural type．
2014, 44(04): 49-51.
Abstract:
Door and window have sizable energy consumption for buildings in hot summer and cold winter zone． For the purpose of studying suitable shading technology for external windows of buildings in hot summer and cold winter zone，this paper surveys the typical shading technology in typical cities Shanghai and Huzhou ( Zhejiang Province) ． The survey shows that horizontal shading board is a common shading technology in this area． Based on which a building energy comsumption analysis model is built． Building energy consumption simulation software DeST is used to research the relationship between the depth of horizontal shading board and building energy consumption in this area． The results of this research will provide a reference foundation for shading reconstruction in hot summer and cold winter zone．
Door and window have sizable energy consumption for buildings in hot summer and cold winter zone． For the purpose of studying suitable shading technology for external windows of buildings in hot summer and cold winter zone，this paper surveys the typical shading technology in typical cities Shanghai and Huzhou ( Zhejiang Province) ． The survey shows that horizontal shading board is a common shading technology in this area． Based on which a building energy comsumption analysis model is built． Building energy consumption simulation software DeST is used to research the relationship between the depth of horizontal shading board and building energy consumption in this area． The results of this research will provide a reference foundation for shading reconstruction in hot summer and cold winter zone．
2014, 44(04): 52-55.
Abstract:
Jingdezhen exactly is a porcelain-based city with distinct personality． Jingdezhen is millenary porcelain city， but the landscape image of its most important street: porcelain streetis faced with further decline now． How to get a specific and vivid landscape image that can embody the continuation of times，and make a rapid development in the modern society are the urgent problems to be solved，which are worth further researching． Based on this background， the research starting from the current theory point of view of the city image，combined with related theories and practices，also with the city development plan of Jingdezhen，it was proposed the design strategy for reconstruction of overall space form and landscape image the porcelain street． In order to keep the unity of the space dimension and continuity in the time dimension，to arouse the peoples collective memory，it was also put forward feasible solutions for constructing the traditional vitality and traditional landscape imagery of the porcelain street．
Jingdezhen exactly is a porcelain-based city with distinct personality． Jingdezhen is millenary porcelain city， but the landscape image of its most important street: porcelain streetis faced with further decline now． How to get a specific and vivid landscape image that can embody the continuation of times，and make a rapid development in the modern society are the urgent problems to be solved，which are worth further researching． Based on this background， the research starting from the current theory point of view of the city image，combined with related theories and practices，also with the city development plan of Jingdezhen，it was proposed the design strategy for reconstruction of overall space form and landscape image the porcelain street． In order to keep the unity of the space dimension and continuity in the time dimension，to arouse the peoples collective memory，it was also put forward feasible solutions for constructing the traditional vitality and traditional landscape imagery of the porcelain street．
2014, 44(04): 56-59.
Abstract:
prestressed fabricated PC frame structure as a new type of precast concrete structure，opened up new ways of industrial production of prestressed structures． In order to use this structure better in actual projects，the research on the ductility of the preloaded prestressed concrete frame structure and its beam ends moment amplitude-modulation capacity would have important theoretical significance and practical value． Based on a single-layer double span-frame structure，it was researched and analysed the moment amplitude-modulating coefficient values from the plastic hinge rotation capacity and crack width，whose results were in good agreement with the experimental results．
prestressed fabricated PC frame structure as a new type of precast concrete structure，opened up new ways of industrial production of prestressed structures． In order to use this structure better in actual projects，the research on the ductility of the preloaded prestressed concrete frame structure and its beam ends moment amplitude-modulation capacity would have important theoretical significance and practical value． Based on a single-layer double span-frame structure，it was researched and analysed the moment amplitude-modulating coefficient values from the plastic hinge rotation capacity and crack width，whose results were in good agreement with the experimental results．
2014, 44(04): 60-64.
Abstract:
It is described the research on cast-in-place phosphogypsum for residential structure and the summary of construction technology according to the engineering practice． Phosphogypsum，phosphorus slag power，slaked lime and cement are mixed into dry material，and then water reducing agent，retarder and water are added to stir，and 27 cube specimens considering 9 kinds of mixture ratio are made to test the compressive strength and radioactive and setting time and moisture content etc． The compressive strength tests show that the standard values of compressive strength of cast-in-place phosphogypsum wall are between 2. 5 ～ 11. 0 MPa，the strength design values can be 0. 478 times of the standard values，and the phosphogypsum can be used for the filled walls of frame structure and the loadbearing walls of lower small bay residential houses． The volume of the retarder has an obvious effect on the compressive strength of cast-in-place phosphogypsum wall． The detection of the specimens show that the initial setting time and final setting time of cast-in-place phosphogypsum wall are respectively 45 min and 55 min，which can meet the requirements of on-site pouring process，and the results of radioactive test meet the technical requirements of the main material of building． The 5 d moisture content of wall was 2. 6%，which can reach its dry state．
It is described the research on cast-in-place phosphogypsum for residential structure and the summary of construction technology according to the engineering practice． Phosphogypsum，phosphorus slag power，slaked lime and cement are mixed into dry material，and then water reducing agent，retarder and water are added to stir，and 27 cube specimens considering 9 kinds of mixture ratio are made to test the compressive strength and radioactive and setting time and moisture content etc． The compressive strength tests show that the standard values of compressive strength of cast-in-place phosphogypsum wall are between 2. 5 ～ 11. 0 MPa，the strength design values can be 0. 478 times of the standard values，and the phosphogypsum can be used for the filled walls of frame structure and the loadbearing walls of lower small bay residential houses． The volume of the retarder has an obvious effect on the compressive strength of cast-in-place phosphogypsum wall． The detection of the specimens show that the initial setting time and final setting time of cast-in-place phosphogypsum wall are respectively 45 min and 55 min，which can meet the requirements of on-site pouring process，and the results of radioactive test meet the technical requirements of the main material of building． The 5 d moisture content of wall was 2. 6%，which can reach its dry state．
2014, 44(04): 65-68.
Abstract:
In order to research the mechanical performers of reinforced recycled concrete compression columns，six reinforced recycled concrete columns were designed for axial and eccentric compression experiment． This experiment involved the replacement rate of recycled coarse aggregate，relative eccentricity and stirrup ratio etc． The whole destructive process and failure mode of reinforced recycled concrete columns were observed through the experiment． The cross-sectional stress distribution，deformation，ultimate bearing capacity and other important data were obtained． And the effecting law of each changing parameter on the recycled concrete columnsultimate bearing capacity was analyzed． The results showed that the axial，eccentric compression destructive process and failure mode of reinforced concrete columns were similar to those of ordinary reinforced concrete columns，both showed as crush of concrete． Influence on specimensultimate bearing capacity of relative eccentricity was evident，the ultimate bearing capacity of columns was decreasing with the increase of relative eccentricity，and the replacement rate of recycled coarse aggregate had little effect on the bearing capacity． When using the calculation methods of the ordinary reinforced concrete columns to calculate the reinforced recycled concrete columns， for axial compression strength， the experimental data were smaller than the theoretical data，which was not safe; for eccentric compression strength，the experimental data were bigger than the theoretical data．
In order to research the mechanical performers of reinforced recycled concrete compression columns，six reinforced recycled concrete columns were designed for axial and eccentric compression experiment． This experiment involved the replacement rate of recycled coarse aggregate，relative eccentricity and stirrup ratio etc． The whole destructive process and failure mode of reinforced recycled concrete columns were observed through the experiment． The cross-sectional stress distribution，deformation，ultimate bearing capacity and other important data were obtained． And the effecting law of each changing parameter on the recycled concrete columnsultimate bearing capacity was analyzed． The results showed that the axial，eccentric compression destructive process and failure mode of reinforced concrete columns were similar to those of ordinary reinforced concrete columns，both showed as crush of concrete． Influence on specimensultimate bearing capacity of relative eccentricity was evident，the ultimate bearing capacity of columns was decreasing with the increase of relative eccentricity，and the replacement rate of recycled coarse aggregate had little effect on the bearing capacity． When using the calculation methods of the ordinary reinforced concrete columns to calculate the reinforced recycled concrete columns， for axial compression strength， the experimental data were smaller than the theoretical data，which was not safe; for eccentric compression strength，the experimental data were bigger than the theoretical data．
2014, 44(04): 69-72.
Abstract:
In this paper，the test of the Z-shape shear specimen of CGM to concrete showed how water mixing ratio， curing age and the CGM strength level affected the interfacial bonding properties of CGM to concrete． The result indicated that the interfacial bonding properties increased with the growth of the bonding age，and the growth rate gradually decreased． When repaired the old concrete with CGM，the shear strength of CGM to concrete decreased with the increase in the strength of the CGM ( the decreasing of the water mixing ratio) ． The cube compressive strength decreased with the fluidity increasing which was due to the increment of the water mixing ratio，but it was favorable to the improvement of the bonding performance of CGM to concrete．
In this paper，the test of the Z-shape shear specimen of CGM to concrete showed how water mixing ratio， curing age and the CGM strength level affected the interfacial bonding properties of CGM to concrete． The result indicated that the interfacial bonding properties increased with the growth of the bonding age，and the growth rate gradually decreased． When repaired the old concrete with CGM，the shear strength of CGM to concrete decreased with the increase in the strength of the CGM ( the decreasing of the water mixing ratio) ． The cube compressive strength decreased with the fluidity increasing which was due to the increment of the water mixing ratio，but it was favorable to the improvement of the bonding performance of CGM to concrete．
2014, 44(04): 73-77.
Abstract:
Aiming at the high performance concrete in bridge engineering，bonding restrained shrinkage experiment of old and new concrete slabs with the different interface roughness and curing duration were conducted to investigate the early time-varying characteristics of the temperature and humidity of concrete and analyze the impact of curing duration on shrinkage stress of new concrete and bonding surface． The experimental results show that the thickness of new concrete impacted by the restraint of old concrete increases and the inner tensile stress of new concrete decreases with increasing of the roughness of bonding surface，however it is not so prominent for the effect of roughness on the shrinkage at bonding surface; the shrinkage strain of section reduces with reduction of the distance of section to bonding surface and reaches minimum at bonding surface，which reflects prominent inhomogeneity and increases gradually with concrete age; extending the curing duration can reduce shrinkage deformation and tensile stress induced by internal inhomogeneous shrinkage of concrete，thus reducing the risk of early crack of concrete slab．
Aiming at the high performance concrete in bridge engineering，bonding restrained shrinkage experiment of old and new concrete slabs with the different interface roughness and curing duration were conducted to investigate the early time-varying characteristics of the temperature and humidity of concrete and analyze the impact of curing duration on shrinkage stress of new concrete and bonding surface． The experimental results show that the thickness of new concrete impacted by the restraint of old concrete increases and the inner tensile stress of new concrete decreases with increasing of the roughness of bonding surface，however it is not so prominent for the effect of roughness on the shrinkage at bonding surface; the shrinkage strain of section reduces with reduction of the distance of section to bonding surface and reaches minimum at bonding surface，which reflects prominent inhomogeneity and increases gradually with concrete age; extending the curing duration can reduce shrinkage deformation and tensile stress induced by internal inhomogeneous shrinkage of concrete，thus reducing the risk of early crack of concrete slab．
2014, 44(04): 78-82.
Abstract:
In terms of the shortcomings of present manufacturing process，a new preparation technology for composites foam sandwich tube has been established． Whose specimens were made and the effects of cores surface treatment and interwining force on the failure mode and ultimate resistant capacity were studied． According to the effects，some corresponding improment measures were put forward which would ensure that the inner and outer tubes of the composite sandwich tubes could give full play to their superior properties when they work together．
In terms of the shortcomings of present manufacturing process，a new preparation technology for composites foam sandwich tube has been established． Whose specimens were made and the effects of cores surface treatment and interwining force on the failure mode and ultimate resistant capacity were studied． According to the effects，some corresponding improment measures were put forward which would ensure that the inner and outer tubes of the composite sandwich tubes could give full play to their superior properties when they work together．
2014, 44(04): 83-89.
Abstract:
The peak strength of over-consolidated clay is not only related to the degree of consolidation，it is also impacted by stress paths． The method based on the unified hardening model ( UH model) and the generalized nonlinear strength criterion was analyzed the peak strength of over-consolidated clay and offered the theory basis for the over-consolidated clay under complex stress paths． By describing the peak strength of over-consolidated clay under the triaxial compression， constant principal stress，and undrainage consolidation stress path，the relationship of their peak strength could get by UH model． Generalized nonlinear strength criterion was used to describe the non-linear degree of the three paths and to determine the expression equation． The comparation with the test results showed that the proposed analysis method was effective．
The peak strength of over-consolidated clay is not only related to the degree of consolidation，it is also impacted by stress paths． The method based on the unified hardening model ( UH model) and the generalized nonlinear strength criterion was analyzed the peak strength of over-consolidated clay and offered the theory basis for the over-consolidated clay under complex stress paths． By describing the peak strength of over-consolidated clay under the triaxial compression， constant principal stress，and undrainage consolidation stress path，the relationship of their peak strength could get by UH model． Generalized nonlinear strength criterion was used to describe the non-linear degree of the three paths and to determine the expression equation． The comparation with the test results showed that the proposed analysis method was effective．
2014, 44(04): 90-93.
Abstract:
Based on the engineering practice，a new type reinforced soil composed of coal gangue-geogrid-sand was put forward． By direct shear tests and pull-out tests，the interface characteristics of the layered structure in different normal stress were tested and compared with that of common type of geogrid reinforced coal gangue． The results showed that the interface properties of the layered system were similar to those of a common reinforced earth system． Due to filling effect of sand，the compactness of reinforced layer was improved and the interface between filling and reinforcement was increased，the interface strength was higher and played earlier． Moreover，the new layered reinforced system could provide drainage channels for reinforced coal gangue that could avoid softening of coal gangue．
Based on the engineering practice，a new type reinforced soil composed of coal gangue-geogrid-sand was put forward． By direct shear tests and pull-out tests，the interface characteristics of the layered structure in different normal stress were tested and compared with that of common type of geogrid reinforced coal gangue． The results showed that the interface properties of the layered system were similar to those of a common reinforced earth system． Due to filling effect of sand，the compactness of reinforced layer was improved and the interface between filling and reinforcement was increased，the interface strength was higher and played earlier． Moreover，the new layered reinforced system could provide drainage channels for reinforced coal gangue that could avoid softening of coal gangue．
2014, 44(04): 94-98.
Abstract:
The mechanical properties of sand with layered structure is different from the pure sand or the mixed sand containing a certain content of fine particle． The study used the method of sand settling in water to prepare silty sand of sediment deposition in the self-made box，and investigated the law of development of dynamic pore water pressure in the saturated silty sand of sediment deposition through dynamic triaxial liquefaction test． The following conclusions were drawn from the test results: Dynamic pore water pressure could not reach the effective consolidation pressure of saturated silty sand of sediment deposition，it was only 70% ～ 80% of effective consolidation pressure，but the corresponding double amplitude axial strain could reach 0. 05; When the confining pressure was 50 kPa，its dynamic pore pressure model could be expressed by the arcsine function; When the confining pressure was 100 kPa and 200 kPa，its dynamic pore pressure model could be expressed by the hyperbolic function．
The mechanical properties of sand with layered structure is different from the pure sand or the mixed sand containing a certain content of fine particle． The study used the method of sand settling in water to prepare silty sand of sediment deposition in the self-made box，and investigated the law of development of dynamic pore water pressure in the saturated silty sand of sediment deposition through dynamic triaxial liquefaction test． The following conclusions were drawn from the test results: Dynamic pore water pressure could not reach the effective consolidation pressure of saturated silty sand of sediment deposition，it was only 70% ～ 80% of effective consolidation pressure，but the corresponding double amplitude axial strain could reach 0. 05; When the confining pressure was 50 kPa，its dynamic pore pressure model could be expressed by the arcsine function; When the confining pressure was 100 kPa and 200 kPa，its dynamic pore pressure model could be expressed by the hyperbolic function．
2014, 44(04): 99-103.
Abstract:
Large scale deep excavation is normally followed by construction of serried engineering piles inside the excavation zone，and unloading and rebound of soil induced by deep excavation have a great influence on those engineering piles． The mechanical characteristics of the pile groups in the bottom of foundation during the process of deep excavation were studied through building plane finite element model by ABAQUS software，and it was determined the lifting extent of pile block，pile-soil relative displacement，pile shaft force，and side friction of pile． Finally，each engineering pile was reloaded when excavation came to an end，then it was made judgments about their compressive bearing capacity and uplift bearing capacity according to the Q-s curve． The results showed that the bearing capacity of the engineering piles was related to their positions in the foundation excavation plane．
Large scale deep excavation is normally followed by construction of serried engineering piles inside the excavation zone，and unloading and rebound of soil induced by deep excavation have a great influence on those engineering piles． The mechanical characteristics of the pile groups in the bottom of foundation during the process of deep excavation were studied through building plane finite element model by ABAQUS software，and it was determined the lifting extent of pile block，pile-soil relative displacement，pile shaft force，and side friction of pile． Finally，each engineering pile was reloaded when excavation came to an end，then it was made judgments about their compressive bearing capacity and uplift bearing capacity according to the Q-s curve． The results showed that the bearing capacity of the engineering piles was related to their positions in the foundation excavation plane．
2014, 44(04): 104-110.
Abstract:
Taking Guiyang Huaguoyuan Art Center Project for example，it was introduced successful application of slant climbing formwork technology for 1 m thick tilt 67. 43 super thick-big tilt angle shear wall． It was also expounded the process principle of the technique and construction process，it was analyzed the shear and pull resistance of the embedded system and through experiment，the antislip of the force bolt and climbed cone and that of the high strength screw rod，climbed cone and buried pieces board were also analyzed． It was known through experiment that in embedded system，shear failure occurred first in the embedded parts． Hence it was useful for the safety of the project by properly thickening the embedded parts in this climbing formwork system，which provided a reference for similar projects．
Taking Guiyang Huaguoyuan Art Center Project for example，it was introduced successful application of slant climbing formwork technology for 1 m thick tilt 67. 43 super thick-big tilt angle shear wall． It was also expounded the process principle of the technique and construction process，it was analyzed the shear and pull resistance of the embedded system and through experiment，the antislip of the force bolt and climbed cone and that of the high strength screw rod，climbed cone and buried pieces board were also analyzed． It was known through experiment that in embedded system，shear failure occurred first in the embedded parts． Hence it was useful for the safety of the project by properly thickening the embedded parts in this climbing formwork system，which provided a reference for similar projects．
2014, 44(04): 111-114.
Abstract:
Building rubbish can be used in highway subgrades in order to solve the contradiction of the sustainable development and the shortage of sandstone aggregate． The paper introduced construction technology of building rubbish filling subgraded by combining with the test section of the Xuyu Highway． The research was done from the main building rubbish processing and staking，base treatment，transportation，burden distribution，leveling and rolling． The compacted settlement difference and porosity were used as the evaluation index of compaction quality． The result shows that the approach in this paper is feasible，which not only can reduce the negative impact on the ecological environment caused by the mining of the stone，but also remarkable social and economic benefits be got． All these can supply references for the use of future building wastes in subgrade constructions．
Building rubbish can be used in highway subgrades in order to solve the contradiction of the sustainable development and the shortage of sandstone aggregate． The paper introduced construction technology of building rubbish filling subgraded by combining with the test section of the Xuyu Highway． The research was done from the main building rubbish processing and staking，base treatment，transportation，burden distribution，leveling and rolling． The compacted settlement difference and porosity were used as the evaluation index of compaction quality． The result shows that the approach in this paper is feasible，which not only can reduce the negative impact on the ecological environment caused by the mining of the stone，but also remarkable social and economic benefits be got． All these can supply references for the use of future building wastes in subgrade constructions．
2014, 44(04): 115-121.
Abstract:
It is a basic trend of building and housing industrialization，promoted by Chinese government，and developing precast concrete structures can realize the total architectural goals of low carbon，green，environmental protection and energy saving． Based on the integral disassembling features of precast shear wall systems( PSWS) ，this paper presents the fundamental design principle of vertical connections for the PSWS． Structural details of seven types of these connections are systematically summed up． including their respective advantages and disadvantages． Precast shear wall structure of the existing vertical connection form has been used in practical engineering，but there are still shortcomings，which needs further research and development of more reasonable connection forms．
It is a basic trend of building and housing industrialization，promoted by Chinese government，and developing precast concrete structures can realize the total architectural goals of low carbon，green，environmental protection and energy saving． Based on the integral disassembling features of precast shear wall systems( PSWS) ，this paper presents the fundamental design principle of vertical connections for the PSWS． Structural details of seven types of these connections are systematically summed up． including their respective advantages and disadvantages． Precast shear wall structure of the existing vertical connection form has been used in practical engineering，but there are still shortcomings，which needs further research and development of more reasonable connection forms．
2014, 44(04): 122-127.
Abstract:
The moment of inertia of fillet welds is an important factor for calculation of strength of welds when the tubular joint is subjected to in-plane bending． This paper conducts the analysis of weld profile such as the effective area and the moment of inertia． The numerical method adopts the effective section presumption for welds and takes the consideration of dihedral angle，which is the angle between the chord and the brace surfaces along the intersection line，to evaluate the weld profile． Based on the finite element analysis，the approach formula for moment of inertia and the strength calculation of fillet welds for tubular joints under in-plane bending are proposed． The comparison of the results by the approach formula and finite element analysis indicates the safety of the bending strength calculation of fillet welds by the method based on the analysis of weld profile．
The moment of inertia of fillet welds is an important factor for calculation of strength of welds when the tubular joint is subjected to in-plane bending． This paper conducts the analysis of weld profile such as the effective area and the moment of inertia． The numerical method adopts the effective section presumption for welds and takes the consideration of dihedral angle，which is the angle between the chord and the brace surfaces along the intersection line，to evaluate the weld profile． Based on the finite element analysis，the approach formula for moment of inertia and the strength calculation of fillet welds for tubular joints under in-plane bending are proposed． The comparison of the results by the approach formula and finite element analysis indicates the safety of the bending strength calculation of fillet welds by the method based on the analysis of weld profile．
2014, 44(04): 128-130.
Abstract:
The bearing capacity of single angle steel with local deformation is analyzed through nonlinear finite element analysis and limit bearing capacity test research， formulas without including whole buckling are derived，which can calculate the bearing capacity of single angle steel with local deformation when it is in use ，which can judge the local deformation is a safety hidden danger or not．
The bearing capacity of single angle steel with local deformation is analyzed through nonlinear finite element analysis and limit bearing capacity test research， formulas without including whole buckling are derived，which can calculate the bearing capacity of single angle steel with local deformation when it is in use ，which can judge the local deformation is a safety hidden danger or not．
2014, 44(04): 131-134.
Abstract:
Wrapping BFRP sheets on the steel tube can effectively increase the axial capacity and improve the ductility and durability of concrete-filled steel tubes ( CFST) ． This paper presented an experimental study on the axial compressive capacity of the CFST wrapped with BFRP sheets． Four CFST specimens wrapped with BFRP sheet and 3 plain CFST specimens were tested under axial loading，which were analysed by the load - displacement curves and load -strain curves． The experimental results show that 4 strengthened specimens were failed by BFRP rupturing after steel tube buckling． The axial capacity of the CFST was improved by 17. 3% through wrapping BFRP and the ductility of the CFST was improved as well． The good agreement between the experimental axial capacity and the analytical results confirms the validity of the theoretical analysis．
Wrapping BFRP sheets on the steel tube can effectively increase the axial capacity and improve the ductility and durability of concrete-filled steel tubes ( CFST) ． This paper presented an experimental study on the axial compressive capacity of the CFST wrapped with BFRP sheets． Four CFST specimens wrapped with BFRP sheet and 3 plain CFST specimens were tested under axial loading，which were analysed by the load - displacement curves and load -strain curves． The experimental results show that 4 strengthened specimens were failed by BFRP rupturing after steel tube buckling． The axial capacity of the CFST was improved by 17. 3% through wrapping BFRP and the ductility of the CFST was improved as well． The good agreement between the experimental axial capacity and the analytical results confirms the validity of the theoretical analysis．
2014, 44(04): 135-139.
Abstract:
Based on the test results of steel reinforcement high strength high performance concrete ( SＲHSHPC) short columns subjected to cyclic loading，the aspect span ratios，concrete strength，axial compression ratios，stirrups ratios and steel ratios were studied． According to principle of superposition，the shear strength equation was established by considering the contribution of the reinforcement concrete，steel，axial compression and displacement ductility demand for the diagonal shear failure and the shear bond failure． To evaluate the accuracy of the proposed approach，the shear strength predicted by the proposed approach was compared with test results． The resulta showed that the proposed approach could estimate the shear strength of test specimens with reasonable precision． The results can supply a theoretic basis and a reference for the engineer design and revision of technical specification for steel reinforced concrete composite structures．
Based on the test results of steel reinforcement high strength high performance concrete ( SＲHSHPC) short columns subjected to cyclic loading，the aspect span ratios，concrete strength，axial compression ratios，stirrups ratios and steel ratios were studied． According to principle of superposition，the shear strength equation was established by considering the contribution of the reinforcement concrete，steel，axial compression and displacement ductility demand for the diagonal shear failure and the shear bond failure． To evaluate the accuracy of the proposed approach，the shear strength predicted by the proposed approach was compared with test results． The resulta showed that the proposed approach could estimate the shear strength of test specimens with reasonable precision． The results can supply a theoretic basis and a reference for the engineer design and revision of technical specification for steel reinforced concrete composite structures．
2014, 44(04): 140-145.
Abstract:
On the basis of cable net optimization，shape-finding and initial prestress determination，by taking the lowest structure weight as objective function， an optical model of two-way bean string was established，which includes three levels cross-section optimization of cable ，top chord and secondary member such as strut． Stress constraint， local stability constraint and displacement constraint were all considered on this optimization model． Then a two-step and three-level optimization design method of the beam string was raised by the APDL program on ANSYS optimization module． The example shows that the result of this optimization method can be converged fastly，which can be used for initial design of practical projects．
On the basis of cable net optimization，shape-finding and initial prestress determination，by taking the lowest structure weight as objective function， an optical model of two-way bean string was established，which includes three levels cross-section optimization of cable ，top chord and secondary member such as strut． Stress constraint， local stability constraint and displacement constraint were all considered on this optimization model． Then a two-step and three-level optimization design method of the beam string was raised by the APDL program on ANSYS optimization module． The example shows that the result of this optimization method can be converged fastly，which can be used for initial design of practical projects．
2014, 44(04): 146-151.
Abstract:
It was introduced recent studies in China on the instability of steel beams，summarized the widely accepted conclusions from study on beam instability，and stated the demand required by the safety index to codify the beam stability factors． A new formula，named as modified ECCS curve，is proposed for the beam stability factor and a comparison between suggested and a currently used curves on beam stability factors is presented．
It was introduced recent studies in China on the instability of steel beams，summarized the widely accepted conclusions from study on beam instability，and stated the demand required by the safety index to codify the beam stability factors． A new formula，named as modified ECCS curve，is proposed for the beam stability factor and a comparison between suggested and a currently used curves on beam stability factors is presented．
2014, 44(04): 152-156.
Abstract:
The Old National Museum of China was built in August 1959． Due to restrictions in that period，the museum could not meet its usage requirements． It has been found that damages occurred in some structural members and the structures is insufficient for aseismatic ability，which can not meet requirements of relevant standards． In order to reduce engineering and implement the concept of green design，the reasonable reinforcing project is given with fully considering development of the future technology． While maintaining the original construction under the premise of historical style and features， the aseismatic capability of buildings has been enhanced and the building function has been improved by using comprehensive analysis methods and new technologies． Some useful experiences have been got in the implementation of green concept in public buildings of structural retrofitting and strengthening．
The Old National Museum of China was built in August 1959． Due to restrictions in that period，the museum could not meet its usage requirements． It has been found that damages occurred in some structural members and the structures is insufficient for aseismatic ability，which can not meet requirements of relevant standards． In order to reduce engineering and implement the concept of green design，the reasonable reinforcing project is given with fully considering development of the future technology． While maintaining the original construction under the premise of historical style and features， the aseismatic capability of buildings has been enhanced and the building function has been improved by using comprehensive analysis methods and new technologies． Some useful experiences have been got in the implementation of green concept in public buildings of structural retrofitting and strengthening．
2014, 44(04): 157-161.
Abstract:
It is a key for rock-soil anchor used in deep excavation support to assess anchoring quality by nondestructive testing method based on reasonable analysis of dynamic response curve of acceleration signal received by dynamic data recorder． So there different kinds of anchor models were designed for wholly grouted mortar bolts which had no defect，one defect，and two defects．Received the response curves of acceleration signals by tapping test，reappeared in computer by Matlab，then the vibration waveforms could be analyzed and contrasted by wavelet analysis，so the inner connexion between the vibration waveform and every model was established，which could reflected the three measure parameters，i． e． the period of a single cycle，the frequency value of time-frequency spectrum，and the deadening of energy． The results showed the rules of dynamic responses could be correctly reflected by the time domain waveforms and time-frequency spectrum for different anchor qualities． that were the faster of stress wave deadening in bolt，the better of anchor quality．
It is a key for rock-soil anchor used in deep excavation support to assess anchoring quality by nondestructive testing method based on reasonable analysis of dynamic response curve of acceleration signal received by dynamic data recorder． So there different kinds of anchor models were designed for wholly grouted mortar bolts which had no defect，one defect，and two defects．Received the response curves of acceleration signals by tapping test，reappeared in computer by Matlab，then the vibration waveforms could be analyzed and contrasted by wavelet analysis，so the inner connexion between the vibration waveform and every model was established，which could reflected the three measure parameters，i． e． the period of a single cycle，the frequency value of time-frequency spectrum，and the deadening of energy． The results showed the rules of dynamic responses could be correctly reflected by the time domain waveforms and time-frequency spectrum for different anchor qualities． that were the faster of stress wave deadening in bolt，the better of anchor quality．
2014, 44(04): 162-166.
Abstract:
Because of the change of functions，a five-story frame-shear wall industrial workshop was reconstructed to a nine-story frame structure building used as top quality office building． The field inspection and seismic appraisal of the original building were conducted，the results showed that the building could meet various requirements of the present Chinese code basically． Based on the actual situation，like original large-span prestressed beam section was too high， the indoor retrofitting design program was made． Strengthening designs were proposed， including strengthening its base with two kinds of pile foundations，enlarging cross-section of original frame column and sticking CFRP laminates． Structure after adding layers was analyzed，settlement monitoring during the transformation process was carried out，and the retrofitting effect was excellent．
Because of the change of functions，a five-story frame-shear wall industrial workshop was reconstructed to a nine-story frame structure building used as top quality office building． The field inspection and seismic appraisal of the original building were conducted，the results showed that the building could meet various requirements of the present Chinese code basically． Based on the actual situation，like original large-span prestressed beam section was too high， the indoor retrofitting design program was made． Strengthening designs were proposed， including strengthening its base with two kinds of pile foundations，enlarging cross-section of original frame column and sticking CFRP laminates． Structure after adding layers was analyzed，settlement monitoring during the transformation process was carried out，and the retrofitting effect was excellent．
2014, 44(04): 167-170.
Abstract:
For the basement of tall，Superhigh and complex multi-layer structure，with basements the following issues are the most important ones for designers in analysis and design of these kinds of buildings，such as how to consider the effect of partial fixing in basement，and how to rationally simplify the computation model of the structures． Aiming at verify the reasonability of basement roof as partial fixing in high structure standard，this article analysed the lateral structure chosen at random in the basement of the lateral stiffness and stiffness ratio of superstructure floor basement．
For the basement of tall，Superhigh and complex multi-layer structure，with basements the following issues are the most important ones for designers in analysis and design of these kinds of buildings，such as how to consider the effect of partial fixing in basement，and how to rationally simplify the computation model of the structures． Aiming at verify the reasonability of basement roof as partial fixing in high structure standard，this article analysed the lateral structure chosen at random in the basement of the lateral stiffness and stiffness ratio of superstructure floor basement．
2014, 44(04): 171-173.
Abstract:
Unlike the slow and inefficient passenger transportation of traditional railway service，high-speed railway service is featured by its convenience，time-saving，comfort and heavy capacity． Taking the building of Taiyuan High- Speed Passenger Station for example，through a work of proper layout and architectural design，a great achievement of architectural culture and advanced technologies like the novel roof system，panel wall system and the energy-efficient layout，has been precisely tailored for the high-speed railway system，which can attract more and more passengers to enjoy the safe，efficient and comfort service of passenger transportation．
Unlike the slow and inefficient passenger transportation of traditional railway service，high-speed railway service is featured by its convenience，time-saving，comfort and heavy capacity． Taking the building of Taiyuan High- Speed Passenger Station for example，through a work of proper layout and architectural design，a great achievement of architectural culture and advanced technologies like the novel roof system，panel wall system and the energy-efficient layout，has been precisely tailored for the high-speed railway system，which can attract more and more passengers to enjoy the safe，efficient and comfort service of passenger transportation．
