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2012 Vol. 42, No. 1
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2012, 42(1): 1-7,61.
doi: 10.13204/j.gyjz201201001
Abstract:
High strength steel has been gradually applied in construction industry.As the strength of steel increases,the property of toughness degrades to some extent,particularly in the case of application at low temperature.Therefore,it is necessary to study the impact toughness of high strength steel.Impact toughness tests of 14 mm thick Q460-C steel at low temperature were performed,Charpy impact power level was compared with that of 60,90,120,and 150 mm thick Q345 steel at the same temperature respectively,besides the scanning electronic microscope of the Charpy-type specimen fracture surfaces with different temperature points were analyzed.And the results showed that:1)The impact toughness of Q460-C steel decrease with the descending temperature;2)Between 20 ℃ and-20 ℃,the low temperature impact power level of 14 mm thick Q460-C was lower than that of 150,120,90 mm and 60 mm thick Q345 at the same temperature;3)The influence of steel strength on low temperature brittleness of Q460-C was less obvious than that of steel depth on that of Q345;4)The fracture appearances of Charpy-type specimens of Q460-C,which break at-20 ℃ had finished the transition form ductile to brittle on the whole,with a large of significant brittle characteristics.Meanwhile,a Boltzmann function fit analysis was made on Charpy impact test results of Q460-C,obtaining-11.1 ℃ as the brittle ductile transition temperature.Test results showed that the low temperature brittleness of Q460-C and its welding seam were apparent,to which much attention should be paid.
High strength steel has been gradually applied in construction industry.As the strength of steel increases,the property of toughness degrades to some extent,particularly in the case of application at low temperature.Therefore,it is necessary to study the impact toughness of high strength steel.Impact toughness tests of 14 mm thick Q460-C steel at low temperature were performed,Charpy impact power level was compared with that of 60,90,120,and 150 mm thick Q345 steel at the same temperature respectively,besides the scanning electronic microscope of the Charpy-type specimen fracture surfaces with different temperature points were analyzed.And the results showed that:1)The impact toughness of Q460-C steel decrease with the descending temperature;2)Between 20 ℃ and-20 ℃,the low temperature impact power level of 14 mm thick Q460-C was lower than that of 150,120,90 mm and 60 mm thick Q345 at the same temperature;3)The influence of steel strength on low temperature brittleness of Q460-C was less obvious than that of steel depth on that of Q345;4)The fracture appearances of Charpy-type specimens of Q460-C,which break at-20 ℃ had finished the transition form ductile to brittle on the whole,with a large of significant brittle characteristics.Meanwhile,a Boltzmann function fit analysis was made on Charpy impact test results of Q460-C,obtaining-11.1 ℃ as the brittle ductile transition temperature.Test results showed that the low temperature brittleness of Q460-C and its welding seam were apparent,to which much attention should be paid.
2012, 42(1): 8-12,102.
doi: 10.13204/j.gyjz201201002
Abstract:
High strength steel has been gradually applied in construction industry.As the strength of steel increases,the property of toughness degrades to some extent,particularly in the case of application at low temperature.Therefore,it is necessary to study the impact toughness of high strength steel.Impact toughness tests of 14 mm thick Q460-C steel at low temperature were performed,Charpy impact power level was compared with that of 60,90,120,and 150 mm thick Q345 steel at the same temperature respectively,besides the scanning electronic microscope of the Charpy-type specimen fracture surfaces with different temperature points were analyzed.And the results showed that:1)The impact toughness of Q460-C steel decrease with the descending temperature;2)Between 20 ℃ and-20 ℃,the low temperature impact power level of 14 mm thick Q460-C was lower than that of 150,120,90 mm and 60 mm thick Q345 at the same temperature;3)The influence of steel strength on low temperature brittleness of Q460-C was less obvious than that of steel depth on that of Q345;4)The fracture appearances of Charpy-type specimens of Q460-C,which break at-20 ℃ had finished the transition form ductile to brittle on the whole,with a large of significant brittle characteristics.Meanwhile,a Boltzmann function fit analysis was made on Charpy impact test results of Q460-C,obtaining-11.1 ℃ as the brittle ductile transition temperature.Test results showed that the low temperature brittleness of Q460-C and its welding seam were apparent,to which much attention should be paid.
High strength steel has been gradually applied in construction industry.As the strength of steel increases,the property of toughness degrades to some extent,particularly in the case of application at low temperature.Therefore,it is necessary to study the impact toughness of high strength steel.Impact toughness tests of 14 mm thick Q460-C steel at low temperature were performed,Charpy impact power level was compared with that of 60,90,120,and 150 mm thick Q345 steel at the same temperature respectively,besides the scanning electronic microscope of the Charpy-type specimen fracture surfaces with different temperature points were analyzed.And the results showed that:1)The impact toughness of Q460-C steel decrease with the descending temperature;2)Between 20 ℃ and-20 ℃,the low temperature impact power level of 14 mm thick Q460-C was lower than that of 150,120,90 mm and 60 mm thick Q345 at the same temperature;3)The influence of steel strength on low temperature brittleness of Q460-C was less obvious than that of steel depth on that of Q345;4)The fracture appearances of Charpy-type specimens of Q460-C,which break at-20 ℃ had finished the transition form ductile to brittle on the whole,with a large of significant brittle characteristics.Meanwhile,a Boltzmann function fit analysis was made on Charpy impact test results of Q460-C,obtaining-11.1 ℃ as the brittle ductile transition temperature.Test results showed that the low temperature brittleness of Q460-C and its welding seam were apparent,to which much attention should be paid.
2012, 42(1): 13-17,55.
doi: 10.13204/j.gyjz201201003
Abstract:
The mechanical properties of steel under monotonic loading and cyclic loading are quite different,because of cyclic hardening,cyclic softening and bauschinger effect.Based on the monotonic and cyclic loading experiment of structural steel Q345 and Q460,the comparison of monotonic performance,cyclic loading phenomenon,cyclic performance and cyclic constitutive model were analyzed.The results showed that:the ductility was good under monotonic loading and Q460 was better.The stress-strain curves possed of the phenomenon of cyclic hardening,cyclic softening,and Bauschinger effect.The hardening was advanced under cyclic loading and Q345 was remarkable.The energy dissipation capacity of Q460 was not lower than Q345,and steel occured cumulative damage under cyclic loading.The mixed hardening model could well simulate the cyclic tension-compression curves,which might provide cyclic constitutive model accurately of Q345 and Q460 to study the seismic behavior of steel structures.
The mechanical properties of steel under monotonic loading and cyclic loading are quite different,because of cyclic hardening,cyclic softening and bauschinger effect.Based on the monotonic and cyclic loading experiment of structural steel Q345 and Q460,the comparison of monotonic performance,cyclic loading phenomenon,cyclic performance and cyclic constitutive model were analyzed.The results showed that:the ductility was good under monotonic loading and Q460 was better.The stress-strain curves possed of the phenomenon of cyclic hardening,cyclic softening,and Bauschinger effect.The hardening was advanced under cyclic loading and Q345 was remarkable.The energy dissipation capacity of Q460 was not lower than Q345,and steel occured cumulative damage under cyclic loading.The mixed hardening model could well simulate the cyclic tension-compression curves,which might provide cyclic constitutive model accurately of Q345 and Q460 to study the seismic behavior of steel structures.
2012, 42(1): 18-25,36.
doi: 10.13204/j.gyjz201201004
Abstract:
Aiming at the local buckling behavior of high strength steel welded box section columns,four axial compression tests of Q460 square box section stub columns were conducted.Based on the test results,the relation of buckling stress and ultimate stress of specimens with different width-to-thickness ratios were studied.Besides,test results were compared with the corresponding design methods and calculation formulae in Chinese,American,European steel structures design codes and method proposed by Chen Shaofan.The research work showed that the effective areas decreased and the post-buckling strength increased with width-to-thickness ratios;the value of the buckling stress of square box section stub columns in the Chinese steel structures design code was unreasonable;the calculation results of the American,European steel structures design codes and the design method proposed by Chen Shaofan were close,which were all little higher than the test results,so all the design methods were reasonable.A new design method was proposed to predict buckling stress of Q460 square box section stub columns,which was in need of revision;the design method proposed by Chen Shaofan and the calculating formula of Eurocode 3,which was in need of revision,were recommended to predict ultimate stress of Q460 square box section stub columns.
Aiming at the local buckling behavior of high strength steel welded box section columns,four axial compression tests of Q460 square box section stub columns were conducted.Based on the test results,the relation of buckling stress and ultimate stress of specimens with different width-to-thickness ratios were studied.Besides,test results were compared with the corresponding design methods and calculation formulae in Chinese,American,European steel structures design codes and method proposed by Chen Shaofan.The research work showed that the effective areas decreased and the post-buckling strength increased with width-to-thickness ratios;the value of the buckling stress of square box section stub columns in the Chinese steel structures design code was unreasonable;the calculation results of the American,European steel structures design codes and the design method proposed by Chen Shaofan were close,which were all little higher than the test results,so all the design methods were reasonable.A new design method was proposed to predict buckling stress of Q460 square box section stub columns,which was in need of revision;the design method proposed by Chen Shaofan and the calculating formula of Eurocode 3,which was in need of revision,were recommended to predict ultimate stress of Q460 square box section stub columns.
2012, 42(1): 26-31,69.
doi: 10.13204/j.gyjz201201005
Abstract:
In order to investigate the behavior of Q460 high strength steel welded box columns under axial compression,numerical analysis was performed with both numerical integration method(NIM)and finite element method(FEM).The numerical models were based on the previous experiments conducted by authors.The measured initial geometric imperfections and simplified distributions of residual stresses were taken into account in the numerical models.The predicted results obtained through NIM and FEM showed a good agreement with each other.The comparison of test results with numerical results was presented for verifying the NIM program.It was demonstrated that both NIM and FEM,which took initial imperfections into account,could predict reliable results of the behavior of Q460 high strength steel welded box columns under axial compression.Moreover,the accuracy of the simplified distributions of residual stresses was verified by comparing the FEM results considering measured distributions with FEM results considering simplified distributions.
In order to investigate the behavior of Q460 high strength steel welded box columns under axial compression,numerical analysis was performed with both numerical integration method(NIM)and finite element method(FEM).The numerical models were based on the previous experiments conducted by authors.The measured initial geometric imperfections and simplified distributions of residual stresses were taken into account in the numerical models.The predicted results obtained through NIM and FEM showed a good agreement with each other.The comparison of test results with numerical results was presented for verifying the NIM program.It was demonstrated that both NIM and FEM,which took initial imperfections into account,could predict reliable results of the behavior of Q460 high strength steel welded box columns under axial compression.Moreover,the accuracy of the simplified distributions of residual stresses was verified by comparing the FEM results considering measured distributions with FEM results considering simplified distributions.
2012, 42(1): 32-36,25.
doi: 10.13204/j.gyjz201201006
Abstract:
It was presented an experimental investigation on structural behaviour of welded H-sections fabricated from high-strength steel sheet with a nominal yield stress of 460 MPa.A total of six tests were performed on high-strength welded H-sections subjected to axial compression force.The comparison of the test results with the design strengths calculated using the Chinese Code for steel structures showed that the long column design strengths predicted using the curve c specified in the Chinese Code were conservative,while the reliability of the design strengths predicted using the curve b needed to be assessed using reliability analysis.Furthermore,a total of four cyclic loading tests were conducted to study the hysteretic behavior of high-strength welded H-section beam-columns.The test result showed that the Q460 steel welded H-section beam-columns possed good ductility and a certain degree of energy dissipation capacities.
It was presented an experimental investigation on structural behaviour of welded H-sections fabricated from high-strength steel sheet with a nominal yield stress of 460 MPa.A total of six tests were performed on high-strength welded H-sections subjected to axial compression force.The comparison of the test results with the design strengths calculated using the Chinese Code for steel structures showed that the long column design strengths predicted using the curve c specified in the Chinese Code were conservative,while the reliability of the design strengths predicted using the curve b needed to be assessed using reliability analysis.Furthermore,a total of four cyclic loading tests were conducted to study the hysteretic behavior of high-strength welded H-section beam-columns.The test result showed that the Q460 steel welded H-section beam-columns possed good ductility and a certain degree of energy dissipation capacities.
2012, 42(1): 37-45,50.
doi: 10.13204/j.gyjz201201007
Abstract:
The overall buckling behavior of high strength steel columns with nominal yield strength more than 460 MPa was improved a lot compared with the ordinary strength steel columns.The effect of the initial geometrical imperfection and the residual stress on the buckling strength of high strength steel columns was analyzed by using finite element analysis(FEA)method,as well as the change of sensitivity to the initial imperfection.Based on the parameter analysis,including the initial imperfection and the steel strength,it showed that with the increase of the steel strength,the degree of the sensitivity to initial imperfections became lower,especially for the residual stress.Besides,the effect of the imperfection significantly correlated with the slenderness ratio of columns.Finally,the characteristics and advantages of the overall buckling behavior of high strength steel columns were revealed.
The overall buckling behavior of high strength steel columns with nominal yield strength more than 460 MPa was improved a lot compared with the ordinary strength steel columns.The effect of the initial geometrical imperfection and the residual stress on the buckling strength of high strength steel columns was analyzed by using finite element analysis(FEA)method,as well as the change of sensitivity to the initial imperfection.Based on the parameter analysis,including the initial imperfection and the steel strength,it showed that with the increase of the steel strength,the degree of the sensitivity to initial imperfections became lower,especially for the residual stress.Besides,the effect of the imperfection significantly correlated with the slenderness ratio of columns.Finally,the characteristics and advantages of the overall buckling behavior of high strength steel columns were revealed.
2012, 42(1): 46-50,45.
doi: 10.13204/j.gyjz201201008
Abstract:
The mechanical performance of high-strength hot-rolled H-cantilever beam under low cyclic loading by comparative study with Q345-B hot-rolled H-beam was introduced.The deformation behavior and failure mode were discussed,with which the hysteretic loops,skeleton curves,bearing capacity,ductility and energy dissipation coefficient were obtained.The experimental results showed that high-strength hot-rolled H-beam possed large bearing capacity,good ductility and energy dissipation capability.Both the yield strength and initiated stiffness calculated with theoretical formula,and the hysteretic behavior simulated with SAP 2000 were in accordance well with experimental results.
The mechanical performance of high-strength hot-rolled H-cantilever beam under low cyclic loading by comparative study with Q345-B hot-rolled H-beam was introduced.The deformation behavior and failure mode were discussed,with which the hysteretic loops,skeleton curves,bearing capacity,ductility and energy dissipation coefficient were obtained.The experimental results showed that high-strength hot-rolled H-beam possed large bearing capacity,good ductility and energy dissipation capability.Both the yield strength and initiated stiffness calculated with theoretical formula,and the hysteretic behavior simulated with SAP 2000 were in accordance well with experimental results.
2012, 42(1): 51-55,17.
doi: 10.13204/j.gyjz201201009
Abstract:
It was presented an experimental investigation on longitudinal residual stresses of welded H-sections fabricated from high-strength steel sheet with a nominal yield stress of 460 MPa,which was recently developed by Baosteel Group Corporation.Strain gage hole drilling method was used to measure the magnitudes and distributions of longitudinal residual stresses along the cross section.Furthermore,the measured points inside the thickness were stripped to the outer surface to measure the stresses along the thickness of the section.At last,a longitudinal residual stress pattern was proposed based on the test results obtained in this study for the Q460 welded H-sections.
It was presented an experimental investigation on longitudinal residual stresses of welded H-sections fabricated from high-strength steel sheet with a nominal yield stress of 460 MPa,which was recently developed by Baosteel Group Corporation.Strain gage hole drilling method was used to measure the magnitudes and distributions of longitudinal residual stresses along the cross section.Furthermore,the measured points inside the thickness were stripped to the outer surface to measure the stresses along the thickness of the section.At last,a longitudinal residual stress pattern was proposed based on the test results obtained in this study for the Q460 welded H-sections.
2012, 42(1): 56-61,7.
doi: 10.13204/j.gyjz201201010
Abstract:
The use of high strength steel,particularly above grade Q460,has increased in recent years.But there are no regulations on bolted connections with high strength steel.Especially,there are significantly fewer investigations on the influence of end distance,edge distance or bolt spacing on the shear resistance of high strength steel in comparison to mild steel.Therefore,extensive experimental research on bolted connections made of high strength steel under static shear was put.It was tested 10 mm and 12 mm plate of grade Q460 steel.All test specimens with two M27 bolts class 10.9 bolts arranged in a transverse direction to the load axis were assembled with different dimensions to explore the influence of end distance,edge distance and bolt spacing.The objective of the research was to determine the ductility and resistance of such connections.Different failure modes of bolted connections could be observed in the test.The ultimate bearing capacity was compared with that predicted by the current connection provisions specified in Eurocode and AISC steel design standards.Recommendations concerning the adequacy of current design standards with respect to the design of high strength steel bolted connections were proposed.
The use of high strength steel,particularly above grade Q460,has increased in recent years.But there are no regulations on bolted connections with high strength steel.Especially,there are significantly fewer investigations on the influence of end distance,edge distance or bolt spacing on the shear resistance of high strength steel in comparison to mild steel.Therefore,extensive experimental research on bolted connections made of high strength steel under static shear was put.It was tested 10 mm and 12 mm plate of grade Q460 steel.All test specimens with two M27 bolts class 10.9 bolts arranged in a transverse direction to the load axis were assembled with different dimensions to explore the influence of end distance,edge distance and bolt spacing.The objective of the research was to determine the ductility and resistance of such connections.Different failure modes of bolted connections could be observed in the test.The ultimate bearing capacity was compared with that predicted by the current connection provisions specified in Eurocode and AISC steel design standards.Recommendations concerning the adequacy of current design standards with respect to the design of high strength steel bolted connections were proposed.
2012, 42(1): 62-65,103.
doi: 10.13204/j.gyjz201201011
Abstract:
It was described the existing problems of Chinese industrial building design nowadays,it was also pointed out that there was a big contrast between the quality of Chinese industrial building and huge investment.It was thought that Chinese industrial buildings were much approaching to the essence of architecture than civil buildings in China,because it's little influenced by esthetics and politics.At the same time,it was criticized the current design of industrial buildings,which was not only a deviation from spirit of modern architecture,but also a wrong way.It was proposed the reply strategies of industrial building design,i.e.much attention was paid to material feature,structural lectotype and structural joint through the analysis of relevant building theories and case histories,based on actual projects,so as to explore some new design ideas and methods.
It was described the existing problems of Chinese industrial building design nowadays,it was also pointed out that there was a big contrast between the quality of Chinese industrial building and huge investment.It was thought that Chinese industrial buildings were much approaching to the essence of architecture than civil buildings in China,because it's little influenced by esthetics and politics.At the same time,it was criticized the current design of industrial buildings,which was not only a deviation from spirit of modern architecture,but also a wrong way.It was proposed the reply strategies of industrial building design,i.e.much attention was paid to material feature,structural lectotype and structural joint through the analysis of relevant building theories and case histories,based on actual projects,so as to explore some new design ideas and methods.
2012, 42(1): 66-69,31.
doi: 10.13204/j.gyjz201201012
Abstract:
Through reforming an idle standard workshop in a development zone,in order to meet the needs of the development of the food industry,it was briefly introduced the general situation of the project,rebuilding principle,the transformation basis and technical measures;through the examples and from the total plane layout,traffic organization,partition design,fire prevention design production,facade reconstruction,construction component detail design,waterproof engineering and energy saving,it was explored how to reform the standatd workshop into a factory meeting the food hygiene requirements,thus obtaining good economic and social effects.
Through reforming an idle standard workshop in a development zone,in order to meet the needs of the development of the food industry,it was briefly introduced the general situation of the project,rebuilding principle,the transformation basis and technical measures;through the examples and from the total plane layout,traffic organization,partition design,fire prevention design production,facade reconstruction,construction component detail design,waterproof engineering and energy saving,it was explored how to reform the standatd workshop into a factory meeting the food hygiene requirements,thus obtaining good economic and social effects.
2012, 42(1): 70-73.
doi: 10.13204/j.gyjz201201013
Abstract:
It was expounded the concept and feature of industrial architecture heritage in port areas.Based on overseas experience,it was analyzed the significance of regenerating such heritages from history and culture,resource and environment,and economical value.It was also summarized general methods of conservation and regeneration of industrial architecture heritages in port areas,which achieved purposeful development balancing society,economy and environment,and in particular,put forward a newer pattern that would promote the development of port district by setting landscape first,which would provide reference for protecting and renewing such heritages in china.
It was expounded the concept and feature of industrial architecture heritage in port areas.Based on overseas experience,it was analyzed the significance of regenerating such heritages from history and culture,resource and environment,and economical value.It was also summarized general methods of conservation and regeneration of industrial architecture heritages in port areas,which achieved purposeful development balancing society,economy and environment,and in particular,put forward a newer pattern that would promote the development of port district by setting landscape first,which would provide reference for protecting and renewing such heritages in china.
2012, 42(1): 74-77.
doi: 10.13204/j.gyjz201201014
Abstract:
A lane in Jingdezhen is an important material for the study on porcelain culture in Jingdezhen as well as a very unique city street landscape of Jingdezhen.However,due to the removal of porcelain industry,this place was gradually losing its vitality.Based on the study on porcelain culture of Jingdezhen,this paper brought forward the concept of reproduction and reconstruction of lane porcelain cultural system.The lane should be renovated and redesigned under such concept so as to revitalize the lane.
A lane in Jingdezhen is an important material for the study on porcelain culture in Jingdezhen as well as a very unique city street landscape of Jingdezhen.However,due to the removal of porcelain industry,this place was gradually losing its vitality.Based on the study on porcelain culture of Jingdezhen,this paper brought forward the concept of reproduction and reconstruction of lane porcelain cultural system.The lane should be renovated and redesigned under such concept so as to revitalize the lane.
2012, 42(1): 78-84,116.
doi: 10.13204/j.gyjz201201015
Abstract:
In the specifications on detailing of stirrups and minimum hoop characteristic factors in column hoop densified regions,there exists large difference between Chinese Codes and related codes of other countries.So it is necessary to check the seismic behaviors of columns with different transverse reinforcement schemes in different codes.Moreover,it is needed to verify the seismic behaviors of columns designed to Chinese Codes using HRB500 rebars with a higher strength as longitudinal reinforcements.Reverse cyclic loading tests of 9 RC column specimens reinforced with HRB500 rebars were conducted.The test parameters included the transverse reinforcement ratio,hoop characteristic value,stirrup strength and arrangement of stirrups.The effects of these parameters on the failure mechanism,load-deflection hysteretic-curve,ductility,stiffness degradation and energy-dissipating capacity were analyzed.Different behaviors between the columns with HRB500 rebars and those with HRB335 rebars were discussed,with other parameters remaining the same.The results showed that when the details of stirrups in hoop densified regions confirming to the design codes,the columns reinforced with HRB500 rebars could meet the seismic requirements of deformability and ductility.
In the specifications on detailing of stirrups and minimum hoop characteristic factors in column hoop densified regions,there exists large difference between Chinese Codes and related codes of other countries.So it is necessary to check the seismic behaviors of columns with different transverse reinforcement schemes in different codes.Moreover,it is needed to verify the seismic behaviors of columns designed to Chinese Codes using HRB500 rebars with a higher strength as longitudinal reinforcements.Reverse cyclic loading tests of 9 RC column specimens reinforced with HRB500 rebars were conducted.The test parameters included the transverse reinforcement ratio,hoop characteristic value,stirrup strength and arrangement of stirrups.The effects of these parameters on the failure mechanism,load-deflection hysteretic-curve,ductility,stiffness degradation and energy-dissipating capacity were analyzed.Different behaviors between the columns with HRB500 rebars and those with HRB335 rebars were discussed,with other parameters remaining the same.The results showed that when the details of stirrups in hoop densified regions confirming to the design codes,the columns reinforced with HRB500 rebars could meet the seismic requirements of deformability and ductility.
2012, 42(1): 85-88,159.
doi: 10.13204/j.gyjz201201016
Abstract:
Many stairs of frame structure in wenchuan earthquake destroyed seriously,resulting in mass casualties.Research on earthquake damage found that diagonal bracing could not be ignored.The newly revised GB 500112010 Code for Seismic Design of Building pointed that the impact of stairs should be considered in calculating,so D-method was used for calculating simplified model with stairs in order to amend lateral stiffness of structure and force of stairs.Comparing results of analysis method with PKPM(08),it could be Proved that lateral stiffness considering stairs was greater than the one without taking account of stairs,and typical components of stairs had different force results between earthquake action and the those with considering gravity loads.It was proposed that components of stairs should be designed considering earthquake action;stiffness should be calculated considering effect of stairs.
Many stairs of frame structure in wenchuan earthquake destroyed seriously,resulting in mass casualties.Research on earthquake damage found that diagonal bracing could not be ignored.The newly revised GB 500112010 Code for Seismic Design of Building pointed that the impact of stairs should be considered in calculating,so D-method was used for calculating simplified model with stairs in order to amend lateral stiffness of structure and force of stairs.Comparing results of analysis method with PKPM(08),it could be Proved that lateral stiffness considering stairs was greater than the one without taking account of stairs,and typical components of stairs had different force results between earthquake action and the those with considering gravity loads.It was proposed that components of stairs should be designed considering earthquake action;stiffness should be calculated considering effect of stairs.
2012, 42(1): 89-93.
doi: 10.13204/j.gyjz201201017
Abstract:
The calculation of deflection for concrete structural member that was put forward in Code for Design of Concrete Structures was an approximate method.Similar methods were also put forward in some foreign codes or standards for concrete structures.The mentality for this kind of approximation calculation consisted of two steps.Firstly,curvature was calculated with bending moment.Secondly,deflection was calculated by curvature with the help of mechanics.It was unreasonable to calculate deflection by curvature with the help of mechanics.Essentially,the calculation of deflection by curvature was a geometric problem,and integral method should be used to resolve this problem.Based on the numerical equation between the deflection and its derivative or the relation between the derivatwe and the second derivative of deflection in finite integral solution,deflection-curvature matrix was derived by matrix operation,and the curvature-deflection equation was derived with functional relation (x)=-z(x).The curvature-deflection equations for some kinds of common boundary conditions were discussed.The methods and formulae of deflection calculation for concrete structural member were put forward.Calculation showed that it was convenient to improve the approximation calculation of deflection for concrete element by finite integral method.The accuracy of calculation was greatly improved.
The calculation of deflection for concrete structural member that was put forward in Code for Design of Concrete Structures was an approximate method.Similar methods were also put forward in some foreign codes or standards for concrete structures.The mentality for this kind of approximation calculation consisted of two steps.Firstly,curvature was calculated with bending moment.Secondly,deflection was calculated by curvature with the help of mechanics.It was unreasonable to calculate deflection by curvature with the help of mechanics.Essentially,the calculation of deflection by curvature was a geometric problem,and integral method should be used to resolve this problem.Based on the numerical equation between the deflection and its derivative or the relation between the derivatwe and the second derivative of deflection in finite integral solution,deflection-curvature matrix was derived by matrix operation,and the curvature-deflection equation was derived with functional relation (x)=-z(x).The curvature-deflection equations for some kinds of common boundary conditions were discussed.The methods and formulae of deflection calculation for concrete structural member were put forward.Calculation showed that it was convenient to improve the approximation calculation of deflection for concrete element by finite integral method.The accuracy of calculation was greatly improved.
2012, 42(1): 94-97,148.
doi: 10.13204/j.gyjz201201018
Abstract:
In a tier building or tall building with frame structure,the total building structural system consists of stairs structure and frame structure.This total structural system may be called frame-stairs system.Unreasonable joints of stairs structure can bring some bad characteristics of this frame-stairs system.Such unreasonable stairs may be destroyed badly in earthquake,and escape way may be cut off.The bad characteristics of this structural system were shown by push-over analysis.Based on the conclusions of push-over analysis,a kind of reasonable joint of stairs structure in frame-stairs system was put forward.By this kind of joint,the way transfering horizontal loads down in stairs was cut off.In this case,stairs elements won't participate in transfering down horizontal earthquake actions of building,and the destruction of stairs elements might be avoided.Adopting such structure,it may be possible for stairs to become safety island.
In a tier building or tall building with frame structure,the total building structural system consists of stairs structure and frame structure.This total structural system may be called frame-stairs system.Unreasonable joints of stairs structure can bring some bad characteristics of this frame-stairs system.Such unreasonable stairs may be destroyed badly in earthquake,and escape way may be cut off.The bad characteristics of this structural system were shown by push-over analysis.Based on the conclusions of push-over analysis,a kind of reasonable joint of stairs structure in frame-stairs system was put forward.By this kind of joint,the way transfering horizontal loads down in stairs was cut off.In this case,stairs elements won't participate in transfering down horizontal earthquake actions of building,and the destruction of stairs elements might be avoided.Adopting such structure,it may be possible for stairs to become safety island.
2012, 42(1): 98-102.
doi: 10.13204/j.gyjz201201019
Abstract:
This paper investigated the effect of cyclic wetting and drying on the engineering properties of lime or fly ash stabilized expansive soils.For this purpose,by means of a series of lab tests,it was evaluated the effect of cyclic wetting and drying on swell percent,Atterberg limits,grain size distribution,and unconfined compressive strength of stabilized expansive soils.Test results showed that the stabilized expansive soils experienced an increase in swelling percent,liquid limit,plasticity index,and clay fraction content upon cyclic wetting and drying,and a reduction in plastic limit,silt fraction content,and unconfined compressive strength upon cyclic wetting and drying.
This paper investigated the effect of cyclic wetting and drying on the engineering properties of lime or fly ash stabilized expansive soils.For this purpose,by means of a series of lab tests,it was evaluated the effect of cyclic wetting and drying on swell percent,Atterberg limits,grain size distribution,and unconfined compressive strength of stabilized expansive soils.Test results showed that the stabilized expansive soils experienced an increase in swelling percent,liquid limit,plasticity index,and clay fraction content upon cyclic wetting and drying,and a reduction in plastic limit,silt fraction content,and unconfined compressive strength upon cyclic wetting and drying.
2012, 42(1): 103-109.
doi: 10.13204/j.gyjz201201020
Abstract:
The strength reduction FEM was adopted to analyze slope stability influenced by the gradient of inclined rock ground as well as interface roughness between the fills and the ground.Safety factors,the most dangerous sliding surface as well as their difference from those calculated by the simplified Bishop method were presented.The results showed that for filled slope on inclined intact rock ground,the sliding surface was quite different from circular surface in some cases.There would be considerable error if safety factors were calculated by the simplified Bishop method.Furthermore,for filled slope on inclined intact rock ground with non-full rough interface,there were restriction mechanisms of the inclined rock ground with relatively high strength and weaking mechanisms of the interface,acting on the sliding surface.The former enhanced slope stability,while the latter acted the opposite.The calculation also showed that FEM with strength reduction,applied to the stability analysis of high filled slopes on mountainous ground,could give more realistic shape and position of the sliding surface and consequently more reliable results for the safety factor.In contrast,the conventional limit equilibrium analysis methods,with the usual assumption of circular sliding surface,might give poor results for this type of complicated problems.FEM with strength reduction was simple and efficient.Therefore,its application prospect was more extensive than limit equilibrium method.
The strength reduction FEM was adopted to analyze slope stability influenced by the gradient of inclined rock ground as well as interface roughness between the fills and the ground.Safety factors,the most dangerous sliding surface as well as their difference from those calculated by the simplified Bishop method were presented.The results showed that for filled slope on inclined intact rock ground,the sliding surface was quite different from circular surface in some cases.There would be considerable error if safety factors were calculated by the simplified Bishop method.Furthermore,for filled slope on inclined intact rock ground with non-full rough interface,there were restriction mechanisms of the inclined rock ground with relatively high strength and weaking mechanisms of the interface,acting on the sliding surface.The former enhanced slope stability,while the latter acted the opposite.The calculation also showed that FEM with strength reduction,applied to the stability analysis of high filled slopes on mountainous ground,could give more realistic shape and position of the sliding surface and consequently more reliable results for the safety factor.In contrast,the conventional limit equilibrium analysis methods,with the usual assumption of circular sliding surface,might give poor results for this type of complicated problems.FEM with strength reduction was simple and efficient.Therefore,its application prospect was more extensive than limit equilibrium method.
2012, 42(1): 110-116,84.
doi: 10.13204/j.gyjz201201021
Abstract:
The design and construction of twin tunnels are key questions in the study of shield tunnel.To obtain the influence of spaces on internal forces in lining,the model including layer,equivalent circle zone and lining was established.At first,the model was checked by calculating the field monitored data,and it was confirmed the one was relible and reasonable.Then the impact of space,covered depth and soil parameters on the soil stress and the internal forces in the lining were calculated.From the results of soil stress,it could be obtained that the unloading areas of tunnels come to overlap and the stress of the soil between the twin tunnels increased while the space decreased,then the internal forces was increased.From the result of the internal forces,the improving ratios of the maximal internal forces under various conditions were obtained.And the results showed that the impact of covered depth and the cohesion of soil on the improving ratio was little and the impact of the internal friction angle was notable.Then the improving ratio of design value of the maximal internal forces in the lining under various conditions was given.At last,with the comprehension of analysis results,some design and construction suggestions were given for the problems in shield twin tunnels.
The design and construction of twin tunnels are key questions in the study of shield tunnel.To obtain the influence of spaces on internal forces in lining,the model including layer,equivalent circle zone and lining was established.At first,the model was checked by calculating the field monitored data,and it was confirmed the one was relible and reasonable.Then the impact of space,covered depth and soil parameters on the soil stress and the internal forces in the lining were calculated.From the results of soil stress,it could be obtained that the unloading areas of tunnels come to overlap and the stress of the soil between the twin tunnels increased while the space decreased,then the internal forces was increased.From the result of the internal forces,the improving ratios of the maximal internal forces under various conditions were obtained.And the results showed that the impact of covered depth and the cohesion of soil on the improving ratio was little and the impact of the internal friction angle was notable.Then the improving ratio of design value of the maximal internal forces in the lining under various conditions was given.At last,with the comprehension of analysis results,some design and construction suggestions were given for the problems in shield twin tunnels.
2012, 42(1): 117-122,127.
doi: 10.13204/j.gyjz201201022
Abstract:
Considering the interaction of building-soil-tunnel,the raft foundation masonry structure was vertically crossed by double-O-tube(DOT) shield tunnel,which was simulated by the 3D MIDAS/GTS software.The additional settlement and force of structure caused by tunnel construction were analyzed,and the changes of building's floor and the axis distance between building and shield tunnel were considered.The results showed that during the passage of the DOT shield tunnel through the building,the settlement of the building increased;the settlement was stable and had a little rebound when shield machine passed the building;the building had short uneven settlement in driving direction,and it increased first from zero then gradually decreased to zero;the maximum first principal stress 1 and the wall maximum shear strain increased and then was stable.With the increase of axis distance between building and tunnel,the building tended towards to tunnel side,the incline of local foundation increased first and then decreased;the maximal 1 and the maximal shear strain were all remained unchanged within a certain range,and then gradually decreased gradually and approached to their initial value.With the increase of building's floor,the maximal shear strain linearly increased,and it would cause minor damage to the building.
Considering the interaction of building-soil-tunnel,the raft foundation masonry structure was vertically crossed by double-O-tube(DOT) shield tunnel,which was simulated by the 3D MIDAS/GTS software.The additional settlement and force of structure caused by tunnel construction were analyzed,and the changes of building's floor and the axis distance between building and shield tunnel were considered.The results showed that during the passage of the DOT shield tunnel through the building,the settlement of the building increased;the settlement was stable and had a little rebound when shield machine passed the building;the building had short uneven settlement in driving direction,and it increased first from zero then gradually decreased to zero;the maximum first principal stress 1 and the wall maximum shear strain increased and then was stable.With the increase of axis distance between building and tunnel,the building tended towards to tunnel side,the incline of local foundation increased first and then decreased;the maximal 1 and the maximal shear strain were all remained unchanged within a certain range,and then gradually decreased gradually and approached to their initial value.With the increase of building's floor,the maximal shear strain linearly increased,and it would cause minor damage to the building.
2012, 42(1): 123-127,122.
doi: 10.13204/j.gyjz201201023
Abstract:
The failure modes of underreamed ground anchors in sand under vertical pullout,which were embedded in various depths,were researched by model test.The test results exhibited three different modes of failure depending on the embedment ratio.The rupture surface of shallow underreamed anchor presented like an inverted bell,inclined slightly inward as it extended to the sand surface.The failure mode of shallow underreamed anchor was known as general shear failure,shallow underreamed anchors should not be used in practice.The rupture surface of deep underreamed anchor was completely limited inside sand and presented like a ellipsoid.There was no deformation in the shallow sand layer either during or after pullout,and the failure of underreamed anchors embedded in deep sand resulted from local shear failure.It was highly recommended to apply the deep underreamed ground anchors in design.There was another type of underreamed anchor between shallow and deep underreamed anchors,namely the transitional anchor,and a combined failure surface of the anchor was appeared in the failure zone.But the failure mode of the transitional anchor was near to the shallow one,which was classified as the shallow failure mode.
The failure modes of underreamed ground anchors in sand under vertical pullout,which were embedded in various depths,were researched by model test.The test results exhibited three different modes of failure depending on the embedment ratio.The rupture surface of shallow underreamed anchor presented like an inverted bell,inclined slightly inward as it extended to the sand surface.The failure mode of shallow underreamed anchor was known as general shear failure,shallow underreamed anchors should not be used in practice.The rupture surface of deep underreamed anchor was completely limited inside sand and presented like a ellipsoid.There was no deformation in the shallow sand layer either during or after pullout,and the failure of underreamed anchors embedded in deep sand resulted from local shear failure.It was highly recommended to apply the deep underreamed ground anchors in design.There was another type of underreamed anchor between shallow and deep underreamed anchors,namely the transitional anchor,and a combined failure surface of the anchor was appeared in the failure zone.But the failure mode of the transitional anchor was near to the shallow one,which was classified as the shallow failure mode.
2012, 42(1): 128-132.
doi: 10.13204/j.gyjz201201024
Abstract:
Dynamic consolidation is widely used in foundation reinforcement projects,but how to choose the ramming energy is still a difficult matter in foundation reinforcement project.The effects of ramming energy on the improvement of saturated hydraulic fill were studied.Here,different ramming energies were used in three fields with the same geological conditions of soil layer.It was compared the variations of the depth of pit with the numbers of drops and passes,the evolutions of pore pressure with time,the variation of the settlement of ground surface,and the variation of the lateral displacement along depth.The studies showed that there was an appropriate ramming energy.Besides,the results of static cone penetration tests,standard penetration tests and loading plate test were analyzed.Studies showed that ramming energy was an important factor in saturated foundation reinforcement project;there was an optimal ramming energy under which the consolidation of saturated foundation could achieve great effect.
Dynamic consolidation is widely used in foundation reinforcement projects,but how to choose the ramming energy is still a difficult matter in foundation reinforcement project.The effects of ramming energy on the improvement of saturated hydraulic fill were studied.Here,different ramming energies were used in three fields with the same geological conditions of soil layer.It was compared the variations of the depth of pit with the numbers of drops and passes,the evolutions of pore pressure with time,the variation of the settlement of ground surface,and the variation of the lateral displacement along depth.The studies showed that there was an appropriate ramming energy.Besides,the results of static cone penetration tests,standard penetration tests and loading plate test were analyzed.Studies showed that ramming energy was an important factor in saturated foundation reinforcement project;there was an optimal ramming energy under which the consolidation of saturated foundation could achieve great effect.
2012, 42(1): 133-136.
doi: 10.13204/j.gyjz201201025
Abstract:
Carbonation of high performance concrete under freeze-thaw cycles was studied with different fly ash proportion(0%,20%,40%,60%);the new rules to estimate carbonation of concrete under freeze-thaw cycles were defined.The influence of different fly ash proportion and different freeze-thaw damage on carbonation was analyzed quantitatively by image processing techniques.Experiment results showed that the carbonation of concrete after freeze-thaw cycles was different from the traditional carbonation of concrete.The traditional testing method using carbonation depth could not express new feature of carbonation after freeze-thaw damage.And the new testing method using carbonation area could better express the carbonation law.The carbonation area and fly ash proportion subject quadratic equation =45.12-1.35FA+0.035FA2;and the carbonation area and freeze-thaw damage degree linear equation =35+0.306x.The research on the carbonation of concrete under freeze-thaw cycles possesses the real meaning to the structure durability and life prediction of concrete in the freeze-thaw area.
Carbonation of high performance concrete under freeze-thaw cycles was studied with different fly ash proportion(0%,20%,40%,60%);the new rules to estimate carbonation of concrete under freeze-thaw cycles were defined.The influence of different fly ash proportion and different freeze-thaw damage on carbonation was analyzed quantitatively by image processing techniques.Experiment results showed that the carbonation of concrete after freeze-thaw cycles was different from the traditional carbonation of concrete.The traditional testing method using carbonation depth could not express new feature of carbonation after freeze-thaw damage.And the new testing method using carbonation area could better express the carbonation law.The carbonation area and fly ash proportion subject quadratic equation =45.12-1.35FA+0.035FA2;and the carbonation area and freeze-thaw damage degree linear equation =35+0.306x.The research on the carbonation of concrete under freeze-thaw cycles possesses the real meaning to the structure durability and life prediction of concrete in the freeze-thaw area.
2012, 42(1): 137-139,153.
doi: 10.13204/j.gyjz201201026
Abstract:
In order to study the Cl-migration under freeze-thaw cycle and the freeze-deicing salt scaling resistance of polypropylene fiber concrete with different volume,indoor artificial method was used to simulate freeze-thaw cycle.The results indicated that the scaled mass and relative dynamic modulus of elasticity loss decrease with the volume of fiber increasing,Cl-concentration had a enrichment near the sample surface,adding 0.1% PPF into concrete had the prefect resistance of deicer-frost scaling.More fibers could delay the development of cracks,but that would reduce the inner density of concrete.
In order to study the Cl-migration under freeze-thaw cycle and the freeze-deicing salt scaling resistance of polypropylene fiber concrete with different volume,indoor artificial method was used to simulate freeze-thaw cycle.The results indicated that the scaled mass and relative dynamic modulus of elasticity loss decrease with the volume of fiber increasing,Cl-concentration had a enrichment near the sample surface,adding 0.1% PPF into concrete had the prefect resistance of deicer-frost scaling.More fibers could delay the development of cracks,but that would reduce the inner density of concrete.
2012, 42(1): 140-143,169.
doi: 10.13204/j.gyjz201201027
Abstract:
The steel fibers used in fiber reinforced concrete were shaped with flattened end or hooked end to strengthen the anchoring effect between the concrete matrix and fibers.However,the mechanical difference of ultra-high performance fiber reinforced concrete(UHPFRC) with these two deformed fibers remains to be confirmed experimentally.In this paper,the end-flattened and end-hooked fibers were used in producing UHPFRC with the fiber volume ratio of 1%,2%,2.5% and 3% to investigate the different fiber reinforcing effect.The results showed that with the fiber volume ratio of 2%,the UHPFRC with end-flattened achieved the best workability and mechanical performance;with the fiber volume ratio of 2%~2.5%,the flexural strength and fracture energy of UHPFRC with end-flattened fibers exceeded that of end-hooked fibers;due to the better anchoring effect,UHPFRC beams with end-hooked fibers behaved more ductile than that with end-flattened fibers after the peak load.
The steel fibers used in fiber reinforced concrete were shaped with flattened end or hooked end to strengthen the anchoring effect between the concrete matrix and fibers.However,the mechanical difference of ultra-high performance fiber reinforced concrete(UHPFRC) with these two deformed fibers remains to be confirmed experimentally.In this paper,the end-flattened and end-hooked fibers were used in producing UHPFRC with the fiber volume ratio of 1%,2%,2.5% and 3% to investigate the different fiber reinforcing effect.The results showed that with the fiber volume ratio of 2%,the UHPFRC with end-flattened achieved the best workability and mechanical performance;with the fiber volume ratio of 2%~2.5%,the flexural strength and fracture energy of UHPFRC with end-flattened fibers exceeded that of end-hooked fibers;due to the better anchoring effect,UHPFRC beams with end-hooked fibers behaved more ductile than that with end-flattened fibers after the peak load.
2012, 42(1): 144-148,97.
doi: 10.13204/j.gyjz201201028
Abstract:
The contradiction between C60 high-performance concrete's viscosity and pumpability was always a major problem in high pumping concrete construction.Taking a high-rise building concrete pumping construction of a tall building for example,it was firstly selected the C60 high-performance concrete proportion of mixture suitable for high pumping,and also verified the critical parameters of the pumping equipment from the theoretical calculations and actual estimates,it was selected the HBT90CH-2135D pumping equipment of Sanyi Heavy Industry,eventually the concrete pumping scheme of two-pump and two-tube to the top layer was used,and it was successfully overcome the contradiction between C60 high-performance concrete's viscosity and pumpability,thus pumping C60 high performance concrete to a height of 383 m smoothly,which had important reference and practical significance to high performance concrete pumping construction for superhigh buildings.
The contradiction between C60 high-performance concrete's viscosity and pumpability was always a major problem in high pumping concrete construction.Taking a high-rise building concrete pumping construction of a tall building for example,it was firstly selected the C60 high-performance concrete proportion of mixture suitable for high pumping,and also verified the critical parameters of the pumping equipment from the theoretical calculations and actual estimates,it was selected the HBT90CH-2135D pumping equipment of Sanyi Heavy Industry,eventually the concrete pumping scheme of two-pump and two-tube to the top layer was used,and it was successfully overcome the contradiction between C60 high-performance concrete's viscosity and pumpability,thus pumping C60 high performance concrete to a height of 383 m smoothly,which had important reference and practical significance to high performance concrete pumping construction for superhigh buildings.
2012, 42(1): 149-153,139.
doi: 10.13204/j.gyjz201201029
Abstract:
Some of the problems such as silo categories,load effect fundamental combination and selection of correlation coefficient,calculation of stored material pressure,structural of design etc.were detected while using GB 500772003 Code for Design of Reinforced Concrete Silos to calculate and design a silo.By elaborating and discussing thoroughly,meaningful conclusions were proposed: the silo structure classification was clear;load effect and seismic action effect combination formulas were analysed;relevant provisions of the stored material load calculating and structure design were explained.
Some of the problems such as silo categories,load effect fundamental combination and selection of correlation coefficient,calculation of stored material pressure,structural of design etc.were detected while using GB 500772003 Code for Design of Reinforced Concrete Silos to calculate and design a silo.By elaborating and discussing thoroughly,meaningful conclusions were proposed: the silo structure classification was clear;load effect and seismic action effect combination formulas were analysed;relevant provisions of the stored material load calculating and structure design were explained.
2012, 42(1): 154-159,88.
doi: 10.13204/j.gyjz201201030
Abstract:
A novel type of steel plate composite shear wall was presented.Four steel plate shear walls specimens and one composite shear wall with various ratio of width-thickness were tested by jack.The failure mode,the shear strength,the lateral stiffness,and the buckling mode were investigated by experiment.The results indicated that ratio of width-thickness of steel plate would determine the shear-carrying capacity and failure mode;and the small ratio of width-thickness of steel plate required adequate anchorage to avoid failure of boundary;although the lateral stiffness of steel plate has little enhancement by the precast concrete plate,the buckling strength and shear strength of steel plate wall were improved by them.Through theoretical analysis,the formula of shear strength of steel plate wall with trilateral constrained and one elastic restraint side,and the one of composite shear wall were proposed based on experiment and numerical simulation.At last,the thicknesses of precast concrete plate applied to steel plate wall with various ratio of width-thickness were presented.
A novel type of steel plate composite shear wall was presented.Four steel plate shear walls specimens and one composite shear wall with various ratio of width-thickness were tested by jack.The failure mode,the shear strength,the lateral stiffness,and the buckling mode were investigated by experiment.The results indicated that ratio of width-thickness of steel plate would determine the shear-carrying capacity and failure mode;and the small ratio of width-thickness of steel plate required adequate anchorage to avoid failure of boundary;although the lateral stiffness of steel plate has little enhancement by the precast concrete plate,the buckling strength and shear strength of steel plate wall were improved by them.Through theoretical analysis,the formula of shear strength of steel plate wall with trilateral constrained and one elastic restraint side,and the one of composite shear wall were proposed based on experiment and numerical simulation.At last,the thicknesses of precast concrete plate applied to steel plate wall with various ratio of width-thickness were presented.
2012, 42(1): 160-163,65.
doi: 10.13204/j.gyjz201201031
Abstract:
Because of the change of functions,a six-story frame industrial workshop was reconstructed to a nine-story frame structure building used as hotel.The field inspection and seismic appraisal of the original building were carried out,the results could meet various requirements of the present Chinese code.According to the problems when storey adding directly,for instance,the ratios of the axial compression to axial compressive strength of some frame columns would be beyond the limit,the longitudinal reinforcement ratios of frame beams would be less than the service level,and some stories drift would be beyond the limit of seismic design code,strengthening designs,including pressure grouting in treatment for foundation like enlarging cross-section of columns and beams,and adding short pier shear wall to increase the lateral displacement stiffness of structure were provided.Based on the analysis of the structure after strengthening,the effect of the seismic strengthening design was excellent.
Because of the change of functions,a six-story frame industrial workshop was reconstructed to a nine-story frame structure building used as hotel.The field inspection and seismic appraisal of the original building were carried out,the results could meet various requirements of the present Chinese code.According to the problems when storey adding directly,for instance,the ratios of the axial compression to axial compressive strength of some frame columns would be beyond the limit,the longitudinal reinforcement ratios of frame beams would be less than the service level,and some stories drift would be beyond the limit of seismic design code,strengthening designs,including pressure grouting in treatment for foundation like enlarging cross-section of columns and beams,and adding short pier shear wall to increase the lateral displacement stiffness of structure were provided.Based on the analysis of the structure after strengthening,the effect of the seismic strengthening design was excellent.
2012, 42(1): 164-168.
doi: 10.13204/j.gyjz201201032
Abstract:
It was comprehensively analysed the gymnasium of a college in Gansu,which was an irregular structure with multi-layer and large space.Considering the fact that its roof-spatial grid structure and lower main-body were made of two different material,it was analysed the spatial co-action principle and earthquake performance between roof-structure and its main-body,a reasonable calculating model was set up.And constructional computing program was used to calculate its anti-earthquake capability,and its calculation results were regulated manually.The design fully considered its construction measure to ensure the engineering safety.
It was comprehensively analysed the gymnasium of a college in Gansu,which was an irregular structure with multi-layer and large space.Considering the fact that its roof-spatial grid structure and lower main-body were made of two different material,it was analysed the spatial co-action principle and earthquake performance between roof-structure and its main-body,a reasonable calculating model was set up.And constructional computing program was used to calculate its anti-earthquake capability,and its calculation results were regulated manually.The design fully considered its construction measure to ensure the engineering safety.
