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2009 Vol. 39, No. 5
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2009, 39(5): 1-5.
doi: 10.13204/j.gyjz200905001
Abstract:
Displacement-based seismic design of RC frames is based on the displacement shape of the RC frame,and multi-degree-of-freedom system is transformed into an effective single-degree-of-freedom system.Based on equivalent linearization,equivalent period is determined by using the elastic-plastic displacement response spectra,and then the structural members are designed.At the same time,target deformability of the beams and columns are obtained by decomposing the structure's storey drift.And the expected deformability of the structure can be guaranteed by appropriate locate the ratio of stirrup.This method could effectively control the seismic performance of the structure in different intensity earthquakes.
Displacement-based seismic design of RC frames is based on the displacement shape of the RC frame,and multi-degree-of-freedom system is transformed into an effective single-degree-of-freedom system.Based on equivalent linearization,equivalent period is determined by using the elastic-plastic displacement response spectra,and then the structural members are designed.At the same time,target deformability of the beams and columns are obtained by decomposing the structure's storey drift.And the expected deformability of the structure can be guaranteed by appropriate locate the ratio of stirrup.This method could effectively control the seismic performance of the structure in different intensity earthquakes.
2009, 39(5): 6-10.
doi: 10.13204/j.gyjz200905002
Abstract:
Based on summarizing theoretical and experimental research results,the practical method is presented for seismic analysis of reinforced concrete frames considering interaction between primary and secondary structures,with the emphases on how to consider interaction between cast-in-situ beam-slab system as well as infilled walls and main frames.And then,taking a modern building with cast-in-situ reinforced concrete structure for example,the effects of interaction between primary and secondary structures on seismic appraisal of existing buildings are analyzed.The example analysis shows that after considering the interaction between cast-in-situ beam-slab system as well as infilled walls and main frames,the stiffness and strength potential of existing structures are fully utilized,the computing structural stiffness is increased distinctly,the computing displacement response is declined rapidly,the seismic bearing capacity is improved evidently,and the evaluating conclusions of safety and seismic behavior are more reasonable and accord with the practical effects.
Based on summarizing theoretical and experimental research results,the practical method is presented for seismic analysis of reinforced concrete frames considering interaction between primary and secondary structures,with the emphases on how to consider interaction between cast-in-situ beam-slab system as well as infilled walls and main frames.And then,taking a modern building with cast-in-situ reinforced concrete structure for example,the effects of interaction between primary and secondary structures on seismic appraisal of existing buildings are analyzed.The example analysis shows that after considering the interaction between cast-in-situ beam-slab system as well as infilled walls and main frames,the stiffness and strength potential of existing structures are fully utilized,the computing structural stiffness is increased distinctly,the computing displacement response is declined rapidly,the seismic bearing capacity is improved evidently,and the evaluating conclusions of safety and seismic behavior are more reasonable and accord with the practical effects.
2009, 39(5): 11-15.
doi: 10.13204/j.gyjz200905003
Abstract:
The non-stationary Kanai-Tajimi model is adopted to simulate the earthquake ground acceleration.In order to describe the intrinsic behavior of the isolation and the structure,a smooth hysteretic restoring model(Bouc-Wen) is introduced.The parameter analysis of the non-linear story isolation structure simulated by two-degree of freedom model is proposed using the equivalent stochastic linearization method.The results demonstrate that the earthquake responses of the story isolation structure are attenuated by shifting the structure's nature vibration characteristic and by the energy dissipation of isolation.Different mass ratio has different focus on control mechanism.
The non-stationary Kanai-Tajimi model is adopted to simulate the earthquake ground acceleration.In order to describe the intrinsic behavior of the isolation and the structure,a smooth hysteretic restoring model(Bouc-Wen) is introduced.The parameter analysis of the non-linear story isolation structure simulated by two-degree of freedom model is proposed using the equivalent stochastic linearization method.The results demonstrate that the earthquake responses of the story isolation structure are attenuated by shifting the structure's nature vibration characteristic and by the energy dissipation of isolation.Different mass ratio has different focus on control mechanism.
2009, 39(5): 16-21.
doi: 10.13204/j.gyjz200905004
Abstract:
The tremendous destruction of the earthquake bad makes the seismic research of structures become a subject extensively concerned.Reinforce concrete shearwalls are critical members in modern high-rise buildings.In the seismic structural wall systems,Frame-wall systems and the frame-core systems,walls are important for ensuring lateral stiffness,contributing to basic earthquake resistance and dissipating energy.In the paper,the advances was introduced in the research on structure,the research on theory of design method,the dynamic testing method.Which may be a reference for seismic investigation on shear walls.
The tremendous destruction of the earthquake bad makes the seismic research of structures become a subject extensively concerned.Reinforce concrete shearwalls are critical members in modern high-rise buildings.In the seismic structural wall systems,Frame-wall systems and the frame-core systems,walls are important for ensuring lateral stiffness,contributing to basic earthquake resistance and dissipating energy.In the paper,the advances was introduced in the research on structure,the research on theory of design method,the dynamic testing method.Which may be a reference for seismic investigation on shear walls.
2009, 39(5): 22-28.
doi: 10.13204/j.gyjz200905005
Abstract:
The ductility of primary lateral resisting member,i.e.core wall is analyzed using finite element program ADINA.The influencing factors like aspect ratio,concrete grade,axial compression ratio,reinforcement ratio,boundary confinement and steel ratio of boundary element etc.are considered in the analysis.Based on the aforementioned research,some suggestions on the design of a core wall in hybrid structure are proposed.
The ductility of primary lateral resisting member,i.e.core wall is analyzed using finite element program ADINA.The influencing factors like aspect ratio,concrete grade,axial compression ratio,reinforcement ratio,boundary confinement and steel ratio of boundary element etc.are considered in the analysis.Based on the aforementioned research,some suggestions on the design of a core wall in hybrid structure are proposed.
2009, 39(5): 29-32,46.
doi: 10.13204/j.gyjz200905006
Abstract:
High strength concrete shear wall embedded polystyrene foam is a new type of multifunction bearing wall.Cyclic loading experiments on three models of these walls are carried out.The bearing capacity,stiffness and its attenuation,ductility,hysteretic property and failure phenomena are investigated.The effects of different reinforcement ratios of inclined steel braces on the seismic performance of the wall are discussed.It is shown that the seismic behavior of the shear wall with inclined brace of steel trusses has been improved much more than that of normal shear wall.Further more,with increasing of the reinforcement ratio,the bearing capacity,the after-stiffness and the ductility have also been improved evidently.
High strength concrete shear wall embedded polystyrene foam is a new type of multifunction bearing wall.Cyclic loading experiments on three models of these walls are carried out.The bearing capacity,stiffness and its attenuation,ductility,hysteretic property and failure phenomena are investigated.The effects of different reinforcement ratios of inclined steel braces on the seismic performance of the wall are discussed.It is shown that the seismic behavior of the shear wall with inclined brace of steel trusses has been improved much more than that of normal shear wall.Further more,with increasing of the reinforcement ratio,the bearing capacity,the after-stiffness and the ductility have also been improved evidently.
2009, 39(5): 33-38.
doi: 10.13204/j.gyjz200905007
Abstract:
On drift capacity of slab-column connection,the code provisions of GB 50011 and UBC 97 and the difference are introduced.By reviewing and analyzing the results of a large number of previously reported tests on slab-column connections,an limited gravity shear ratio on China code is presented.Based on structural analyzing and design examples,a design measure of slab-column shearwall structure is proposed.
On drift capacity of slab-column connection,the code provisions of GB 50011 and UBC 97 and the difference are introduced.By reviewing and analyzing the results of a large number of previously reported tests on slab-column connections,an limited gravity shear ratio on China code is presented.Based on structural analyzing and design examples,a design measure of slab-column shearwall structure is proposed.
2009, 39(5): 39-46.
doi: 10.13204/j.gyjz200905008
Abstract:
In the traditional Pushover method,the vertical earthquake effect,which has an impact on horizontal displacement,is not taken into consideration.When the seismic intensity in vertical direction takes a high ratio,it is hard to accurately estimate the maximum displacement demands on structure by the traditional Pushover method.Hence,the paper aims at making improvement on the traditional one.Firstly,the inertial force caused by vertical earthquake is enforced on structure according to certain means.Then,the multi-mode Pushover analysis procedures are applied in the horizontal direction of structure,and the maximum displacement demand is calculated on the ground of SRSS method.A multistory concrete frame is applied to testify this theory.The data shows that,using the improved method,the numerical results of floor displacement and story drift ratio are well agreed with the results from nonlinear time-history analysis,which demonstrated that the improved method is of high accuracy.
In the traditional Pushover method,the vertical earthquake effect,which has an impact on horizontal displacement,is not taken into consideration.When the seismic intensity in vertical direction takes a high ratio,it is hard to accurately estimate the maximum displacement demands on structure by the traditional Pushover method.Hence,the paper aims at making improvement on the traditional one.Firstly,the inertial force caused by vertical earthquake is enforced on structure according to certain means.Then,the multi-mode Pushover analysis procedures are applied in the horizontal direction of structure,and the maximum displacement demand is calculated on the ground of SRSS method.A multistory concrete frame is applied to testify this theory.The data shows that,using the improved method,the numerical results of floor displacement and story drift ratio are well agreed with the results from nonlinear time-history analysis,which demonstrated that the improved method is of high accuracy.
2009, 39(5): 47-52,55.
doi: 10.13204/j.gyjz200905009
Abstract:
Pushover analysis method is a nonlinear method for structure seismic evaluation,which is widely focused on and studied at home and abroad due to its advantages of simplification,practicality and reliability.It was introduced and analysed the hotspot of research on static elastic-plastic analysis methodlateral loading pattern.Based on which two concrete frame high-rise buildings were analyzed by pushover analysis method based on lateral loading pattern.Last,it was analyzed base shear vs top displacement curve and inter-story drift curve,and concluded that static elastic-plastic analysis method based on uniform distribution load pattern and triangle distribution load pattern has a guidance to elastic-plastic analysis of practical projects and that static elastic-plastic analysis method based on modal adaptive distribution load pattern can be used to evaluate structure seismic performance instead of time-history analysis method.
Pushover analysis method is a nonlinear method for structure seismic evaluation,which is widely focused on and studied at home and abroad due to its advantages of simplification,practicality and reliability.It was introduced and analysed the hotspot of research on static elastic-plastic analysis methodlateral loading pattern.Based on which two concrete frame high-rise buildings were analyzed by pushover analysis method based on lateral loading pattern.Last,it was analyzed base shear vs top displacement curve and inter-story drift curve,and concluded that static elastic-plastic analysis method based on uniform distribution load pattern and triangle distribution load pattern has a guidance to elastic-plastic analysis of practical projects and that static elastic-plastic analysis method based on modal adaptive distribution load pattern can be used to evaluate structure seismic performance instead of time-history analysis method.
2009, 39(5): 53-55.
doi: 10.13204/j.gyjz200905010
Abstract:
As an integral part in the movement of modern architecture,the industrial architectural space of international style further develops the international architectural style,and is considered to be its summit.It is reviewed the social background in which the international style comes into being,and analyzed its formation and development,also defined the elements in developing the industrial architectural space of international style.An last,it is discussed the influence of international style upon the design of Chinese industrial architecture.
As an integral part in the movement of modern architecture,the industrial architectural space of international style further develops the international architectural style,and is considered to be its summit.It is reviewed the social background in which the international style comes into being,and analyzed its formation and development,also defined the elements in developing the industrial architectural space of international style.An last,it is discussed the influence of international style upon the design of Chinese industrial architecture.
2009, 39(5): 56-60,67.
doi: 10.13204/j.gyjz200905011
Abstract:
Aiming at giving assistance to the dasign practice of modern big-space public building,it was summarized the methods of expressing traditional culture in design of outer modality based on the analysis of the excellent architectures in coastal areas of China.Meanwhile,conclude other possible methods as an addition of the existing design means by analyzing the excellent architectures of other countries.
Aiming at giving assistance to the dasign practice of modern big-space public building,it was summarized the methods of expressing traditional culture in design of outer modality based on the analysis of the excellent architectures in coastal areas of China.Meanwhile,conclude other possible methods as an addition of the existing design means by analyzing the excellent architectures of other countries.
2009, 39(5): 61-64,80.
doi: 10.13204/j.gyjz200905012
Abstract:
According to the design case of Houshan Street in Jinkou for matching items of Zhongshanjian,it is explored the renewable sources of commerical old streets.And combining with the patterns and characteristics of the old streets and alleys in south east of E,it is formulated the principle of respecting for the local culture,the peolple,the god,the harmonious development of society,and so on,and also summed up participative rebuilding methods.
According to the design case of Houshan Street in Jinkou for matching items of Zhongshanjian,it is explored the renewable sources of commerical old streets.And combining with the patterns and characteristics of the old streets and alleys in south east of E,it is formulated the principle of respecting for the local culture,the peolple,the god,the harmonious development of society,and so on,and also summed up participative rebuilding methods.
2009, 39(5): 65-67.
doi: 10.13204/j.gyjz200905013
Abstract:
The fatigue test of five concrete beams with slight corrosion reinforcement has been made.The influence of weight loss ratio of reinforcement and stress ratio on the deflection of midspan,maximal crack width and fatigue life of concrete beams has been investigated.Research results show that the midspan deflection of slight corroded beams is lower than that of the non-corroded beams,the maximal crack width of a corroded beam is decreased with an increase in stress rato and the fatigue life is increased with the increase in stress ratio.The experimental results are helpful to the research and assessment of concrete beams with slight corrosion reinforcement.
The fatigue test of five concrete beams with slight corrosion reinforcement has been made.The influence of weight loss ratio of reinforcement and stress ratio on the deflection of midspan,maximal crack width and fatigue life of concrete beams has been investigated.Research results show that the midspan deflection of slight corroded beams is lower than that of the non-corroded beams,the maximal crack width of a corroded beam is decreased with an increase in stress rato and the fatigue life is increased with the increase in stress ratio.The experimental results are helpful to the research and assessment of concrete beams with slight corrosion reinforcement.
2009, 39(5): 68-70.
doi: 10.13204/j.gyjz200905014
Abstract:
The prestressed concrete structure can be used in the large span structure and bears heavy load,comparing to reinforced concrete structure and used widely in projects.In comparison with the post stressed concrete structure,the pre-stressed concrete structure is easy,fast,cost-effective and high-efficient to be built.It is normally used in hollow beams and planks of the span of 13(16,20) meters.It was analyzed that the key procedures,such as the extension calculation of steel strand and its stretching on a long-lines stand,concrete casting etc and precutions of pretensioned PC hollow beams used for an expressway.
The prestressed concrete structure can be used in the large span structure and bears heavy load,comparing to reinforced concrete structure and used widely in projects.In comparison with the post stressed concrete structure,the pre-stressed concrete structure is easy,fast,cost-effective and high-efficient to be built.It is normally used in hollow beams and planks of the span of 13(16,20) meters.It was analyzed that the key procedures,such as the extension calculation of steel strand and its stretching on a long-lines stand,concrete casting etc and precutions of pretensioned PC hollow beams used for an expressway.
2009, 39(5): 71-74.
doi: 10.13204/j.gyjz200905015
Abstract:
The working behavior of single piles with vertical loading is studied by FEM methods.The negative skin friction of piles and pull-down on piles are analyzed.The importance of considering water level change is stressed in pile design.Both the additional settlement and pull-down load on piles due to water level fall should be evaluated.
The working behavior of single piles with vertical loading is studied by FEM methods.The negative skin friction of piles and pull-down on piles are analyzed.The importance of considering water level change is stressed in pile design.Both the additional settlement and pull-down load on piles due to water level fall should be evaluated.
2009, 39(5): 75-80.
doi: 10.13204/j.gyjz200905016
Abstract:
The settlement deformation characteristic and load transfer mechanism of pile-net reinforced embankment are studied through the 3D model test,considering the factors of embankment height,width and clear spacing of pile cap,residual consolidation settlement,compression modulus of soil between piles and geotextile.Some useful test conclusions are obtained.The results of model tests are compared with the calculated results of analytical methods.The results show that for 3D situation,the results obtained from BS 8006's,adapted Terzaghi's and Hewlett's methods are in fair agreement with the results of model tests.And the calculated results of analytical methods are well agreed with the results of model tests with the increasing of width of pile cap.However,the adapted Guido's and Carlsson's methods overestimated the efficiency.The conclusions may be a valuable reference for the design of pile net reinforced embankment.
The settlement deformation characteristic and load transfer mechanism of pile-net reinforced embankment are studied through the 3D model test,considering the factors of embankment height,width and clear spacing of pile cap,residual consolidation settlement,compression modulus of soil between piles and geotextile.Some useful test conclusions are obtained.The results of model tests are compared with the calculated results of analytical methods.The results show that for 3D situation,the results obtained from BS 8006's,adapted Terzaghi's and Hewlett's methods are in fair agreement with the results of model tests.And the calculated results of analytical methods are well agreed with the results of model tests with the increasing of width of pile cap.However,the adapted Guido's and Carlsson's methods overestimated the efficiency.The conclusions may be a valuable reference for the design of pile net reinforced embankment.
2009, 39(5): 81-83,105.
doi: 10.13204/j.gyjz200905017
Abstract:
The model of stratified rock mass is founded by FLAC3D,the size effect of stratified rock mass is analyzed for the situation of the same and different length-diameter ratio,which shows that: 1) for the same length-diameter ratio,the increase of diameter or the height leads to the decrease of compressive strength of stratified rock mass;2) for rock samples with different structure plane inclination,with the increase of length-diameter ratio H/D,the discipline of compressive strength shows differently.The strength of rock mass depends on the certain function of length and diameter,instead of the simply parameter H/D.
The model of stratified rock mass is founded by FLAC3D,the size effect of stratified rock mass is analyzed for the situation of the same and different length-diameter ratio,which shows that: 1) for the same length-diameter ratio,the increase of diameter or the height leads to the decrease of compressive strength of stratified rock mass;2) for rock samples with different structure plane inclination,with the increase of length-diameter ratio H/D,the discipline of compressive strength shows differently.The strength of rock mass depends on the certain function of length and diameter,instead of the simply parameter H/D.
2009, 39(5): 84-88.
doi: 10.13204/j.gyjz200905018
Abstract:
It is set up a fuzzy overall assessment method of concrete bridge durability applying fuzzy theory;based on the multiplayer analysis,this method builds functions that describe the subjection degree of all factors to all grades of durability.Then this method takes the weight of all factors into account and applies the most subjection criterion to get the grade of durability of a concrete bridge,and with this prediction the useful life of durability of the concrete bridge before and after strengthening also can make a quantitatively,so the method is practical.
It is set up a fuzzy overall assessment method of concrete bridge durability applying fuzzy theory;based on the multiplayer analysis,this method builds functions that describe the subjection degree of all factors to all grades of durability.Then this method takes the weight of all factors into account and applies the most subjection criterion to get the grade of durability of a concrete bridge,and with this prediction the useful life of durability of the concrete bridge before and after strengthening also can make a quantitatively,so the method is practical.
2009, 39(5): 89-91,95.
doi: 10.13204/j.gyjz200905019
Abstract:
Results of tests performed on the effect of expansive agent in normal concrete and high volume fly ash concrete are presented.The expansive deformation ratio without restraint and the self-compressive stress under complete restraint are investigated in the tests with temperature-stress test machine(TSTM).The results indicate that combination of fly ash and expansive agent may produce a synergistic effect on the concrete under the specific condition.
Results of tests performed on the effect of expansive agent in normal concrete and high volume fly ash concrete are presented.The expansive deformation ratio without restraint and the self-compressive stress under complete restraint are investigated in the tests with temperature-stress test machine(TSTM).The results indicate that combination of fly ash and expansive agent may produce a synergistic effect on the concrete under the specific condition.
2009, 39(5): 92-95.
doi: 10.13204/j.gyjz200905020
Abstract:
Strength and deformation were studied on plastic concrete in different loading ways through direct and cyclic loading and unloading testing.Conclusions have been drawn: Peak strength reduces generally through cyclic loading,and the degree of change is less than 10%,and the peak strength of cyclic loading and unloading of the maximum value of 60% uniaxial one is more than the others,stress-strain in loading condition does not conform with that in unloading.The area between curve of loading and one of unloading does not change with times of cyclic loading,and increases with increment of the maximum cyclic loading.The slope of the curve of loading is about the same as the one of unloading.The strain of peak strength increase through cyclic loading.
Strength and deformation were studied on plastic concrete in different loading ways through direct and cyclic loading and unloading testing.Conclusions have been drawn: Peak strength reduces generally through cyclic loading,and the degree of change is less than 10%,and the peak strength of cyclic loading and unloading of the maximum value of 60% uniaxial one is more than the others,stress-strain in loading condition does not conform with that in unloading.The area between curve of loading and one of unloading does not change with times of cyclic loading,and increases with increment of the maximum cyclic loading.The slope of the curve of loading is about the same as the one of unloading.The strain of peak strength increase through cyclic loading.
2009, 39(5): 96-100.
doi: 10.13204/j.gyjz200905021
Abstract:
Rapid development of industry caused increase of acidic medium concentration in environments,and the deterioration of concrete performance caused by acidic attack had been paid more attention.In the present paper,five acidic solutions with different pH,different SO_4~(2-) concentration were prepared to simulate acidic rains.The strength variation,sorptivity and pore structure of concrete were measured after acidic attack for 30-150 d,in a dry-wet regimen.Results showed that,after attack of acidic solutions with SO_4~(2-),the strength of concrete reduced at firstly,then increased and reduced at last.It is possible that the reaction products of cement hydrates in concrete with SO_4~(2-) governing property variation of acid attacked concrete.However,after attack of acidic solution without SO_4~(2-),the strength decreased continuously.The reason might be the quality degradation of pore structure after pure acidic attack.
Rapid development of industry caused increase of acidic medium concentration in environments,and the deterioration of concrete performance caused by acidic attack had been paid more attention.In the present paper,five acidic solutions with different pH,different SO_4~(2-) concentration were prepared to simulate acidic rains.The strength variation,sorptivity and pore structure of concrete were measured after acidic attack for 30-150 d,in a dry-wet regimen.Results showed that,after attack of acidic solutions with SO_4~(2-),the strength of concrete reduced at firstly,then increased and reduced at last.It is possible that the reaction products of cement hydrates in concrete with SO_4~(2-) governing property variation of acid attacked concrete.However,after attack of acidic solution without SO_4~(2-),the strength decreased continuously.The reason might be the quality degradation of pore structure after pure acidic attack.
2009, 39(5): 101-105.
doi: 10.13204/j.gyjz200905022
Abstract:
The engineering application of mega-frame structure system,as well as the corresponding theoretical and experimental research methods for seismic performance are reviewed.The direction of further seismic research on these sorts of structures in future is also pointed out.
The engineering application of mega-frame structure system,as well as the corresponding theoretical and experimental research methods for seismic performance are reviewed.The direction of further seismic research on these sorts of structures in future is also pointed out.
2009, 39(5): 106-109,127.
doi: 10.13204/j.gyjz200905023
Abstract:
The fire design of modular house is based on the experience,which is lacking in exact theoretic basis.For getting the using performance and destroy case,finite element theory was used to analyze the carrying capacity and distortion of modular house in four loading combinations,the modular house were provided by Yahgee Company.Reasons and improvements which will provide further useful suggestions on the production and design were given to the company.At the same time,the fireproofing performance of rock wool sandwich panel on the base fire was analyzed by FEM theory and contrasted to that of the test in Sichuan National Supervision Center of Fireproofing Architectural Material Quality.In the end,the fireproofing performance of the integral frame structure with rock wool sandwich panel and EPS sandwich panel in actual projects were analyzed.
The fire design of modular house is based on the experience,which is lacking in exact theoretic basis.For getting the using performance and destroy case,finite element theory was used to analyze the carrying capacity and distortion of modular house in four loading combinations,the modular house were provided by Yahgee Company.Reasons and improvements which will provide further useful suggestions on the production and design were given to the company.At the same time,the fireproofing performance of rock wool sandwich panel on the base fire was analyzed by FEM theory and contrasted to that of the test in Sichuan National Supervision Center of Fireproofing Architectural Material Quality.In the end,the fireproofing performance of the integral frame structure with rock wool sandwich panel and EPS sandwich panel in actual projects were analyzed.
2009, 39(5): 110-114.
doi: 10.13204/j.gyjz200905024
Abstract:
An experimental study on twelve full-size 550 MPa high strength cold-formed steel framing wall studs subjected to centric axial loads is carried out,including six wall studs with single steel rib panel and six wall studs with double wallboards(steel rib panel + gypsum wallboard).Based on the test,the finite element analysis model is established.A parameter analysis of the steel panel,the plate strips,and the spacing of screws of the wall studs subjected to centric axial loads is carried out after the finite element analysis model has been validated by test data.The analysis results may be a reference for design.The analysis results show that replacing the steel rib panel by the steel flat panel which has the same steel consumption will reduce the ultimate load carrying capacity of wall studs with single steel panel largely,but has little influence on the ultimate load carrying capacity of wall studs with double wallboards;it is helpful to enhance the ultimate load carrying capacity of the wall studs with single steel rib panel by setting plate strips on wall studs,but it doesn't have a significant effect on the ultimate load carrying capacity of wall studs with double wallboards;when the spacing of screws connecting wall studs with wallboards is not more than 300 mm,it can't increase the ultimate load carrying capacity of the wall studs by decreasing the spacing of screws;when the spacing of screws around the wall is less than 150 mm,it can't enhance the ultimate load carrying capacity of the wall studs largely by reducing the spacing of screws.
An experimental study on twelve full-size 550 MPa high strength cold-formed steel framing wall studs subjected to centric axial loads is carried out,including six wall studs with single steel rib panel and six wall studs with double wallboards(steel rib panel + gypsum wallboard).Based on the test,the finite element analysis model is established.A parameter analysis of the steel panel,the plate strips,and the spacing of screws of the wall studs subjected to centric axial loads is carried out after the finite element analysis model has been validated by test data.The analysis results may be a reference for design.The analysis results show that replacing the steel rib panel by the steel flat panel which has the same steel consumption will reduce the ultimate load carrying capacity of wall studs with single steel panel largely,but has little influence on the ultimate load carrying capacity of wall studs with double wallboards;it is helpful to enhance the ultimate load carrying capacity of the wall studs with single steel rib panel by setting plate strips on wall studs,but it doesn't have a significant effect on the ultimate load carrying capacity of wall studs with double wallboards;when the spacing of screws connecting wall studs with wallboards is not more than 300 mm,it can't increase the ultimate load carrying capacity of the wall studs by decreasing the spacing of screws;when the spacing of screws around the wall is less than 150 mm,it can't enhance the ultimate load carrying capacity of the wall studs largely by reducing the spacing of screws.
2009, 39(5): 115-117.
doi: 10.13204/j.gyjz200905025
Abstract:
A Cast-steel joint has a strong adaptability,which has been widely used for many large span-space structures,but there is not a unified national design criterion in China.In this case,model test is necessary to the typical complex joints.This paper has made the experimental research on the main joints for the Center of Exhibition and Sport in Nantong,Whose result is also compared with the result of Nonlinear FE analysis.It is proved that the analytic theory used for the project design agrees basically with the actual working condition of the cast-steel joints,and the joints have enough safety reserve.
A Cast-steel joint has a strong adaptability,which has been widely used for many large span-space structures,but there is not a unified national design criterion in China.In this case,model test is necessary to the typical complex joints.This paper has made the experimental research on the main joints for the Center of Exhibition and Sport in Nantong,Whose result is also compared with the result of Nonlinear FE analysis.It is proved that the analytic theory used for the project design agrees basically with the actual working condition of the cast-steel joints,and the joints have enough safety reserve.
2009, 39(5): 118-119,132.
doi: 10.13204/j.gyjz200905026
Abstract:
According to 4.2.4 of the GB 500072002 Code for Design of Building Foundation National Standard,for the preloadedconsolidated foundation,the shear strength parameters may be tested by consolidated-undrained test.Theoretically,the shear strength calculated by strength parameters measured by consolidated-undrained test is not always higher than that calculated from unconsolidated-undrained strength parameters,which might lead to the fact that the ground bearing capacity calculated from CU strength parameters is lower than that from UU strength parameters.The cases are analyzed when it occurs by applying the orthogonal design method and adopting the computational formula of ground bearing capacity and its coefficients of ground bearing capacity offered by the Code.
According to 4.2.4 of the GB 500072002 Code for Design of Building Foundation National Standard,for the preloadedconsolidated foundation,the shear strength parameters may be tested by consolidated-undrained test.Theoretically,the shear strength calculated by strength parameters measured by consolidated-undrained test is not always higher than that calculated from unconsolidated-undrained strength parameters,which might lead to the fact that the ground bearing capacity calculated from CU strength parameters is lower than that from UU strength parameters.The cases are analyzed when it occurs by applying the orthogonal design method and adopting the computational formula of ground bearing capacity and its coefficients of ground bearing capacity offered by the Code.
2009, 39(5): 120-123.
doi: 10.13204/j.gyjz200905027
Abstract:
According to the technics of structure member strengthened with R.C,it is designed that two pieces of composite beams by shaped-steel underpinning(CBSSU) jointed with welded short reinforcing steel bars and one R.C beam in order to contrast their experimentation and analysis.The short period loading test by indoor model is used,and it is observed that several parameters of these beam behaviors,such as limit loadbearing capacity,bending stiffness,flaw condition and stress-strain in the middle section of the beam.On the basis of the experimental study,it can be found that the shaped-steel works in coordination with the R.C beam very well.The CBSSU jointed by welded short reinforcing steel bar gains better bending stiffness,higher limit load-bearing capacity and flaw of the beam can be controlled effectively.
According to the technics of structure member strengthened with R.C,it is designed that two pieces of composite beams by shaped-steel underpinning(CBSSU) jointed with welded short reinforcing steel bars and one R.C beam in order to contrast their experimentation and analysis.The short period loading test by indoor model is used,and it is observed that several parameters of these beam behaviors,such as limit loadbearing capacity,bending stiffness,flaw condition and stress-strain in the middle section of the beam.On the basis of the experimental study,it can be found that the shaped-steel works in coordination with the R.C beam very well.The CBSSU jointed by welded short reinforcing steel bar gains better bending stiffness,higher limit load-bearing capacity and flaw of the beam can be controlled effectively.
2009, 39(5): 124-127.
doi: 10.13204/j.gyjz200905028
Abstract:
Based on the experiment on seismic reinforcement of brick walls with a window strengthened by CFRP under lower cycle reversal loads and the finite element analysis,the seismic reinforcement effectiveness is studied through the comparison of the data on the wall before and after being strengthening,and the different effect of different strengthening ways was compared as well.The study shows that the strengthening effect is obvious.
Based on the experiment on seismic reinforcement of brick walls with a window strengthened by CFRP under lower cycle reversal loads and the finite element analysis,the seismic reinforcement effectiveness is studied through the comparison of the data on the wall before and after being strengthening,and the different effect of different strengthening ways was compared as well.The study shows that the strengthening effect is obvious.
2009, 39(5): 128-132.
doi: 10.13204/j.gyjz200905029
Abstract:
Through experiments on 10 reinforced concrete slabs bonded with thick and thin fireproofing coatings and plain cement mortar respectively,the corresponding temperature distributions of the three cases have been obtained under standard fire condition.The experimental results show that for the FRP strengthened concrete structures,the fireproofing effect by the thin fireproofing coating or plain cement mortar can be neglected.However,the thick fireproofing coating is effective in insulating the FRP strengthened concrete structures,and a formula for calculating the thickness of the fireproofing coating is proposed.
Through experiments on 10 reinforced concrete slabs bonded with thick and thin fireproofing coatings and plain cement mortar respectively,the corresponding temperature distributions of the three cases have been obtained under standard fire condition.The experimental results show that for the FRP strengthened concrete structures,the fireproofing effect by the thin fireproofing coating or plain cement mortar can be neglected.However,the thick fireproofing coating is effective in insulating the FRP strengthened concrete structures,and a formula for calculating the thickness of the fireproofing coating is proposed.
2009, 39(5): 133-136.
doi: 10.13204/j.gyjz200905030
Abstract:
As a leading architectural design firm,Murphy/Jahn's design and practice is an interdisciplinary integration of architecture and engineering.They pay more attention to the environment of the urban,maximize the comfort and minimize the use of technical equipment and energy by advanced and innovative design,and succeed in implementing their ecological and energy efficiency concepts.The style of their works is transparent and clear.It is discussed Murphy/Jahn's special design thinking and approach,which are also analyzed and expatiated by their recent works.
As a leading architectural design firm,Murphy/Jahn's design and practice is an interdisciplinary integration of architecture and engineering.They pay more attention to the environment of the urban,maximize the comfort and minimize the use of technical equipment and energy by advanced and innovative design,and succeed in implementing their ecological and energy efficiency concepts.The style of their works is transparent and clear.It is discussed Murphy/Jahn's special design thinking and approach,which are also analyzed and expatiated by their recent works.
