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2009 Vol. 39, No. 11
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2009, 39(11): 1-4.
doi: 10.13204/j.gyjz200911001
Abstract:
Ribbed bar for construction has an important ratio in the steel production of China,and a higher requirement of production quality has been put forward with the rapid development of economy.In this paper,the microstructure and mechanical properties have been studied and analyzed for HRBF400 fine grain ribbed bar produced with ultra fast cooling techniques,the results show that the strength of ribbed bar can be improved obviously with this technique and has a less degree of decrease in its plastic index.The fine ferrite and pearlite were obtained in the meantime and all kinds of properties can meet the request of national standard.
Ribbed bar for construction has an important ratio in the steel production of China,and a higher requirement of production quality has been put forward with the rapid development of economy.In this paper,the microstructure and mechanical properties have been studied and analyzed for HRBF400 fine grain ribbed bar produced with ultra fast cooling techniques,the results show that the strength of ribbed bar can be improved obviously with this technique and has a less degree of decrease in its plastic index.The fine ferrite and pearlite were obtained in the meantime and all kinds of properties can meet the request of national standard.
2009, 39(11): 5-8.
doi: 10.13204/j.gyjz200911002
Abstract:
The mechanical properties of hot rolled bars of fine grains(HRBF500) after high temperatures were studied experimentally.Eleven groups(33 specimens)were tested after temperatures of 20,100,200,300,400,500,600,700,800,900,and 1 000 ℃,respectively.The variation of yield strength,ultimate strength,elastic modulus,elongation and tensile stress-strain relationship of the HRBF500 at elevated temperatures were investigated and discussed.The results show that the variation of the mechanical property of HRBF500 is not obvious when the highest temperature the reinforcing bar reached is less than 500 ℃;while the stress-strain curves of reinforcing bar become more ductile and the mechanical property indexes of the reinforcing bar degenerate gradually when the highest temperature is more than 500 ℃.Based on the results of the experiment,the calculation formulas for yield strength,ultimate strength,elastic modulus after high temperatures are proposed.All can be served as basic data for analysis of fire resistance and after-fire damage evaluation of structures with hot rolled bars of fine grains(HRBF500).
The mechanical properties of hot rolled bars of fine grains(HRBF500) after high temperatures were studied experimentally.Eleven groups(33 specimens)were tested after temperatures of 20,100,200,300,400,500,600,700,800,900,and 1 000 ℃,respectively.The variation of yield strength,ultimate strength,elastic modulus,elongation and tensile stress-strain relationship of the HRBF500 at elevated temperatures were investigated and discussed.The results show that the variation of the mechanical property of HRBF500 is not obvious when the highest temperature the reinforcing bar reached is less than 500 ℃;while the stress-strain curves of reinforcing bar become more ductile and the mechanical property indexes of the reinforcing bar degenerate gradually when the highest temperature is more than 500 ℃.Based on the results of the experiment,the calculation formulas for yield strength,ultimate strength,elastic modulus after high temperatures are proposed.All can be served as basic data for analysis of fire resistance and after-fire damage evaluation of structures with hot rolled bars of fine grains(HRBF500).
2009, 39(11): 9-12.
doi: 10.13204/j.gyjz200911003
Abstract:
According to the existing process and equipment,the 500 MPa fine graned steel rebar of 20MnSi with ferrite grain size of 5～10 m was successfully developed by adjusting the chemical compositions and new design of deformation parameters of finite roll pass,as well as using new process with controlled rolling and cooling techniques.On the basis of the experience for successfully developing 500 MPa fine graned steel rebar and the analysis of the factors effecting the quality,the solutions are finally proposed
According to the existing process and equipment,the 500 MPa fine graned steel rebar of 20MnSi with ferrite grain size of 5～10 m was successfully developed by adjusting the chemical compositions and new design of deformation parameters of finite roll pass,as well as using new process with controlled rolling and cooling techniques.On the basis of the experience for successfully developing 500 MPa fine graned steel rebar and the analysis of the factors effecting the quality,the solutions are finally proposed
2009, 39(11): 13-16,44.
doi: 10.13204/j.gyjz200911004
Abstract:
Based on 42 HRBF500 steel bar specimens pull-out tests,it is investigated that the bond-anchorage properties of HRBF500 steel bars and the main factors influencing the bond capacity between HRBF500 steel bars and concrete.The test results revealed that its bond strength increases by decreasing anchorage length and bar diameter,increasing stirrup ratio,thickness of concrete cover,yield strength of reinforcing bar and concrete strength,which is similar to that of ordinary crescent ribbed bar,the anchoring length can be designed with the formula in Code for Design of Concrete Structures(GB 500102002),besides,it is proposed that the upper limit of class of concrete strength in formula should be up-dated to C60.
Based on 42 HRBF500 steel bar specimens pull-out tests,it is investigated that the bond-anchorage properties of HRBF500 steel bars and the main factors influencing the bond capacity between HRBF500 steel bars and concrete.The test results revealed that its bond strength increases by decreasing anchorage length and bar diameter,increasing stirrup ratio,thickness of concrete cover,yield strength of reinforcing bar and concrete strength,which is similar to that of ordinary crescent ribbed bar,the anchoring length can be designed with the formula in Code for Design of Concrete Structures(GB 500102002),besides,it is proposed that the upper limit of class of concrete strength in formula should be up-dated to C60.
2009, 39(11): 17-21.
doi: 10.13204/j.gyjz200911005
Abstract:
Based on the experiments of nine eccentrically loaded columns with HRBF500 steel bars and one eccentrically loaded column with HRB400 steel bars,the load-strain curves of steel bars,strain curves of concrete,as well as the characteristics of failure modes were analyzed.The design value of HRBF500 steel bar being 450 MPa in column and the formula of calculating the ultimate strength were proposed based on the experiment and the comprehensive theoretical analysis.
Based on the experiments of nine eccentrically loaded columns with HRBF500 steel bars and one eccentrically loaded column with HRB400 steel bars,the load-strain curves of steel bars,strain curves of concrete,as well as the characteristics of failure modes were analyzed.The design value of HRBF500 steel bar being 450 MPa in column and the formula of calculating the ultimate strength were proposed based on the experiment and the comprehensive theoretical analysis.
2009, 39(11): 22-25.
doi: 10.13204/j.gyjz200911006
Abstract:
Based on the experiments of nine bias columns with 500MPa fine grain bars and one column with HRB400 bars,it was observed that the test' development of the crack and failure mode.Through the analysis of the experimental results 500MPa Fine-grained bias columns' crack width and spacing of the measured values are compared with the calculation results by the code formula.The results show that the measured value that can meet the requirements is less than the one calculated in accordance with existing norms,but the calculated values of crack width in accordance with the norm is greater.The crack width of the bias component is smaller than bending members,components by the stress state impact the crack width;calculation results of crack width by the proposed formula show that the bias component and bending members have the same reliability.
Based on the experiments of nine bias columns with 500MPa fine grain bars and one column with HRB400 bars,it was observed that the test' development of the crack and failure mode.Through the analysis of the experimental results 500MPa Fine-grained bias columns' crack width and spacing of the measured values are compared with the calculation results by the code formula.The results show that the measured value that can meet the requirements is less than the one calculated in accordance with existing norms,but the calculated values of crack width in accordance with the norm is greater.The crack width of the bias component is smaller than bending members,components by the stress state impact the crack width;calculation results of crack width by the proposed formula show that the bias component and bending members have the same reliability.
2009, 39(11): 26-28.
doi: 10.13204/j.gyjz200911007
Abstract:
The experiment on 7 columns with HRBF500 under axial load was done,whose failure mode and bearing capacity subjected to different parameters such as concrete strength,ratio of reinforcement and slenderness ratio have been studied.The results show that the bearing capacity of reinforced concrete short column with HRBF500 is feasible according to the current code.
The experiment on 7 columns with HRBF500 under axial load was done,whose failure mode and bearing capacity subjected to different parameters such as concrete strength,ratio of reinforcement and slenderness ratio have been studied.The results show that the bearing capacity of reinforced concrete short column with HRBF500 is feasible according to the current code.
2009, 39(11): 29-32.
doi: 10.13204/j.gyjz200911008
Abstract:
Six reinforced concrete beams with surface reinforcement and HRBF500 longitudinal reinforcement were tested to investigate their cracking characteristics,and the effects of surface reinforcement on crack spacing and crack width were analyzed.The test results show that the surface reinforcement can reduce crack width effectively,such as the short-time maximum crack width can be reduced by 35% to 65%.Referring the relative provisions in European code EN 1992-1-1:2004,the recommendations on detailing design of surface reinforcements and the reducing ratio of crack width are proposed.
Six reinforced concrete beams with surface reinforcement and HRBF500 longitudinal reinforcement were tested to investigate their cracking characteristics,and the effects of surface reinforcement on crack spacing and crack width were analyzed.The test results show that the surface reinforcement can reduce crack width effectively,such as the short-time maximum crack width can be reduced by 35% to 65%.Referring the relative provisions in European code EN 1992-1-1:2004,the recommendations on detailing design of surface reinforcements and the reducing ratio of crack width are proposed.
2009, 39(11): 33-39.
doi: 10.13204/j.gyjz200911009
Abstract:
In this paper,the material testing of HRBF is firstly taken and its result shows this kind of steel bars posess obvious and sufficient yielding stage and affiliates to a good ductile reinforcing material.Secondly,a total of four specimens of concrete frame beam-column assemblies reinforced with different ratios of HRBF were designed referring to available concrete code.And then the testing of the specimens under cyclic reverse loading was implemented.The performance of concrete beam-column assemblies during the whole process from initial cracking to final failure was tested and such important data as cracking load,ultimate load and load-displacement hysteresis curve for each specimen were recorded and given.The aseismatic indexes for ductility and energy-dispersion of the assemblies were also gained on the basis of testing results.The conclusion from the investigation can be drawn that the concrete beam-column assemblies reinforced with HRBF exibit good aseismatic performance and energy-dispersion performance.
In this paper,the material testing of HRBF is firstly taken and its result shows this kind of steel bars posess obvious and sufficient yielding stage and affiliates to a good ductile reinforcing material.Secondly,a total of four specimens of concrete frame beam-column assemblies reinforced with different ratios of HRBF were designed referring to available concrete code.And then the testing of the specimens under cyclic reverse loading was implemented.The performance of concrete beam-column assemblies during the whole process from initial cracking to final failure was tested and such important data as cracking load,ultimate load and load-displacement hysteresis curve for each specimen were recorded and given.The aseismatic indexes for ductility and energy-dispersion of the assemblies were also gained on the basis of testing results.The conclusion from the investigation can be drawn that the concrete beam-column assemblies reinforced with HRBF exibit good aseismatic performance and energy-dispersion performance.
2009, 39(11): 40-44.
doi: 10.13204/j.gyjz200911010
Abstract:
In order to quantitatively analyze the aseismatic performance of this kind of beam-column assemblies through whole loading history,the non-linear FE analyses of the cross beam-column specimens were carried out by ANSYS.Compared to the experimental results,the finite element analyses cast a further light upon the characteristics of this beam-column assembly while being subject to cyclic reverse loading.Cracking patterns,streel bars's stress distribution and force-displacement curves at beams ends resulted from the experiments indicate that at location of plastic hinge area the main cracks developed sufficiently and the stress of steel bars was peak values,and no bonding failure of steel bars is found within core region of assemblies.It is noticed that the results of finite element analysis of the specimens can properly depict the characteristics and process under loading.
In order to quantitatively analyze the aseismatic performance of this kind of beam-column assemblies through whole loading history,the non-linear FE analyses of the cross beam-column specimens were carried out by ANSYS.Compared to the experimental results,the finite element analyses cast a further light upon the characteristics of this beam-column assembly while being subject to cyclic reverse loading.Cracking patterns,streel bars's stress distribution and force-displacement curves at beams ends resulted from the experiments indicate that at location of plastic hinge area the main cracks developed sufficiently and the stress of steel bars was peak values,and no bonding failure of steel bars is found within core region of assemblies.It is noticed that the results of finite element analysis of the specimens can properly depict the characteristics and process under loading.
2009, 39(11): 45-48.
doi: 10.13204/j.gyjz200911011
Abstract:
City plaza has represented more than the original significance to be the compound of complex function serving,city structure construction,city character expression and raising quality of public livings nowadays,and which is further emphasized by the speciality of a city center plaza.Taking the case of three plazas of Wujiaochang Subcenter of Shanghai to study the importance of the essential factors in the design of a city center plaza,molding the sense of a place and improving space quality etc to the design of such a plaza.
City plaza has represented more than the original significance to be the compound of complex function serving,city structure construction,city character expression and raising quality of public livings nowadays,and which is further emphasized by the speciality of a city center plaza.Taking the case of three plazas of Wujiaochang Subcenter of Shanghai to study the importance of the essential factors in the design of a city center plaza,molding the sense of a place and improving space quality etc to the design of such a plaza.
2009, 39(11): 49-51.
doi: 10.13204/j.gyjz200911012
Abstract:
Ecology and culture is a prominent campus landscape connotations.Campus ecology landscape must be used in principle of landscape ecology,in accordance with respect for nature,diversity,sustainable development and ecological design principles for the campus landscape space to optimize the reconstruction,the formation of a more reasonable ecological landscape spatial configuration.Campus cultural landscape should be fully respected venues cultural context,combined with local culture,to promote Campus cultural history in the process of precipitation,based on their induction,extraction and distillation.
Ecology and culture is a prominent campus landscape connotations.Campus ecology landscape must be used in principle of landscape ecology,in accordance with respect for nature,diversity,sustainable development and ecological design principles for the campus landscape space to optimize the reconstruction,the formation of a more reasonable ecological landscape spatial configuration.Campus cultural landscape should be fully respected venues cultural context,combined with local culture,to promote Campus cultural history in the process of precipitation,based on their induction,extraction and distillation.
2009, 39(11): 52-55.
doi: 10.13204/j.gyjz200911013
Abstract:
At present,it is necessary to develop green architecture at present and the development of green architecture needs the suport of all sectors of society.By analyzing the definition of green architecture,the characteristics and the adoption of real problems and examples summarizs some general green architecture design principles.
At present,it is necessary to develop green architecture at present and the development of green architecture needs the suport of all sectors of society.By analyzing the definition of green architecture,the characteristics and the adoption of real problems and examples summarizs some general green architecture design principles.
2009, 39(11): 56-61.
doi: 10.13204/j.gyjz200911014
Abstract:
The elastic compensation finite element method(ECFEM) is a simple and efficient method of plastic limit analysis,and it is only applicable to a commaterial structure system.An improved algorithm based on ECFEM is proposed by introducing bearing-ratio into the standard algorithm,which not only keeps the basic thought of flattening generalized stress in structure,but also leads the flattening process in proportion with generalized strength of every material.Using this method,all materials reach their generalized strength when the structure system is in its failure mode,and ECFEM can be expanded into the limit analysis of a structure system with multi-material.Contrastive analysis of some classical examples shows that the results using the algorithm are convergent,accurate and stabilizing.Furthermore,the algorithm is also verified to be feasible in safety evaluation of complicated structures by the results of limit load and failure mode.
The elastic compensation finite element method(ECFEM) is a simple and efficient method of plastic limit analysis,and it is only applicable to a commaterial structure system.An improved algorithm based on ECFEM is proposed by introducing bearing-ratio into the standard algorithm,which not only keeps the basic thought of flattening generalized stress in structure,but also leads the flattening process in proportion with generalized strength of every material.Using this method,all materials reach their generalized strength when the structure system is in its failure mode,and ECFEM can be expanded into the limit analysis of a structure system with multi-material.Contrastive analysis of some classical examples shows that the results using the algorithm are convergent,accurate and stabilizing.Furthermore,the algorithm is also verified to be feasible in safety evaluation of complicated structures by the results of limit load and failure mode.
2009, 39(11): 62-67.
doi: 10.13204/j.gyjz200911015
Abstract:
For the purpose of evaluating and retrofitting of cast-in-situ reinforced concrete frames with little reinforcement at beam ends,tests are performed for 7 reinforced concrete continuous beams with cast-in-situ slabs under vertical static load.The effects of cast-in-situ slabs on the structural behavior of continuous beams are studied.Moreover,the stress distribution of concrete and reinforcement in the flange and the change of effective flange width are analyzed.The test results show that the cast-in-situ slabs have notable effects on the stress state,stiffness,failure mode and load-carrying capacity of beams,the increase in the beam flexural strength of support section is especially significant.
For the purpose of evaluating and retrofitting of cast-in-situ reinforced concrete frames with little reinforcement at beam ends,tests are performed for 7 reinforced concrete continuous beams with cast-in-situ slabs under vertical static load.The effects of cast-in-situ slabs on the structural behavior of continuous beams are studied.Moreover,the stress distribution of concrete and reinforcement in the flange and the change of effective flange width are analyzed.The test results show that the cast-in-situ slabs have notable effects on the stress state,stiffness,failure mode and load-carrying capacity of beams,the increase in the beam flexural strength of support section is especially significant.
2009, 39(11): 68-70.
doi: 10.13204/j.gyjz200911016
Abstract:
In order to explore the parameters value range and their determination methods of volume deformation curve of unsaturated soils,the Barcelona model and Wheeler model of unsaturated soils are taken as the research objects,and the different variation law and value range of volume deformation curve are studies by theoretical analysis and formula derivation.Then based on the experiment data of previous report,the above mentioned theories are used to determine the value of volume deformation curve parameter and provide some evidence for parameter assumptions and analogies in numerical simulation.
In order to explore the parameters value range and their determination methods of volume deformation curve of unsaturated soils,the Barcelona model and Wheeler model of unsaturated soils are taken as the research objects,and the different variation law and value range of volume deformation curve are studies by theoretical analysis and formula derivation.Then based on the experiment data of previous report,the above mentioned theories are used to determine the value of volume deformation curve parameter and provide some evidence for parameter assumptions and analogies in numerical simulation.
2009, 39(11): 71-75.
doi: 10.13204/j.gyjz200911017
Abstract:
On the basis of a series of indoor tests for unsaturated Nanning expansive soils through creep testing apparatus controlled by shearing force,nonliner rheological characteristics of the expansive soils were researched.The results show that the soil performs for attenuation when shear stress is less than or equal to 25.5 kPa,but the soil has obvious non linear rheological behavior when shear stress is higher than 25.5 kPa.Through the experiment creep curve can be described by Burgers model,the constitutive equation and the creep equation of the expansive soils also be obtained.
On the basis of a series of indoor tests for unsaturated Nanning expansive soils through creep testing apparatus controlled by shearing force,nonliner rheological characteristics of the expansive soils were researched.The results show that the soil performs for attenuation when shear stress is less than or equal to 25.5 kPa,but the soil has obvious non linear rheological behavior when shear stress is higher than 25.5 kPa.Through the experiment creep curve can be described by Burgers model,the constitutive equation and the creep equation of the expansive soils also be obtained.
2009, 39(11): 76-80.
doi: 10.13204/j.gyjz200911018
Abstract:
The model tests on series of single-pile,two-pile and four-pile foundations were designed to investigate the relation between bearing capacity and settlement under ultimate load and the load share ratio between soil and pile of the composite pile foundation in top-down order.The results indicate that there are two inflexions that are corresponding to the time of sealing pile and the time of foundation collapsion on the load-settlement curve.The settlement of this kind of foundation is less than the shallow foudation's but more than the settlement of the composite foundation and the pile didn't share the load but changed the stiffness of the soil before sealing piles.The time of sealing piles selected in reason could control the load share ratio between pile and siol.The study also shows that the stiffness of the foundation after sealing pile enhanced in large extent and the pile not only bearing the large part of the load in this step but also controlling the settlement very well,and after reaching the pile's ultimate load,the soil turn to be the main body to bear the load.
The model tests on series of single-pile,two-pile and four-pile foundations were designed to investigate the relation between bearing capacity and settlement under ultimate load and the load share ratio between soil and pile of the composite pile foundation in top-down order.The results indicate that there are two inflexions that are corresponding to the time of sealing pile and the time of foundation collapsion on the load-settlement curve.The settlement of this kind of foundation is less than the shallow foudation's but more than the settlement of the composite foundation and the pile didn't share the load but changed the stiffness of the soil before sealing piles.The time of sealing piles selected in reason could control the load share ratio between pile and siol.The study also shows that the stiffness of the foundation after sealing pile enhanced in large extent and the pile not only bearing the large part of the load in this step but also controlling the settlement very well,and after reaching the pile's ultimate load,the soil turn to be the main body to bear the load.
2009, 39(11): 81-85.
doi: 10.13204/j.gyjz200911019
Abstract:
Based on the design and construction scheme of transfer channel in International Trade Station of Beijing Subway No.10 Line,finite difference method is used to simulate the stress characteristic of existing piles and the displacement law during the excavation under subway station transfer channel construction,and the reasonable construction scheme is brought out.It is proved from the result that,if there aren't reinforcement measures on bridge piles,surface subsidence and settlement of bridge piles are large,and the bridge bearing capacity will be reduced seriously,therefore,the stability of bridge piles will be impacted seriously.As a result,during the excavation process of transfer channel,reinforcement measures are necessary to make sure the stability of bridge piles.
Based on the design and construction scheme of transfer channel in International Trade Station of Beijing Subway No.10 Line,finite difference method is used to simulate the stress characteristic of existing piles and the displacement law during the excavation under subway station transfer channel construction,and the reasonable construction scheme is brought out.It is proved from the result that,if there aren't reinforcement measures on bridge piles,surface subsidence and settlement of bridge piles are large,and the bridge bearing capacity will be reduced seriously,therefore,the stability of bridge piles will be impacted seriously.As a result,during the excavation process of transfer channel,reinforcement measures are necessary to make sure the stability of bridge piles.
2009, 39(11): 86-89.
doi: 10.13204/j.gyjz200911020
Abstract:
Through the application of the cable-steel roof of Jilin Speed Skating Rink,the construction characteristics of the mast full hinged suspension structure were summarized;full simulative construction analysis process in which error factors of the steel structure and cable making and erection were taken into account fully was discussed;the conception and method carried out on prestressed spatial structure that prestress should be applied compositely was put forward.
Through the application of the cable-steel roof of Jilin Speed Skating Rink,the construction characteristics of the mast full hinged suspension structure were summarized;full simulative construction analysis process in which error factors of the steel structure and cable making and erection were taken into account fully was discussed;the conception and method carried out on prestressed spatial structure that prestress should be applied compositely was put forward.
2009, 39(11): 90-92.
doi: 10.13204/j.gyjz200911021
Abstract:
The monolithic moving test of a nine-story structure model was carried out,and test conclusion was drawn about a linear relationship between the pull force and the structure weight and the roller diameter,and the pull force formula was draw from the measured data and the practical pull force data from lots of moving projects.
The monolithic moving test of a nine-story structure model was carried out,and test conclusion was drawn about a linear relationship between the pull force and the structure weight and the roller diameter,and the pull force formula was draw from the measured data and the practical pull force data from lots of moving projects.
2009, 39(11): 93-99.
doi: 10.13204/j.gyjz200911022
Abstract:
From 1998 to 2008 cable-supported structures(CSS) have been developed immediately and become as a kind of prestress hybrid steel structure system,including one-way CSS,two-way CSS and spatial CSS.The project uses and state-of-arts of two-way CSS and spatial CSS were introduced in this paper.Some problems needing attention were also discussed.
From 1998 to 2008 cable-supported structures(CSS) have been developed immediately and become as a kind of prestress hybrid steel structure system,including one-way CSS,two-way CSS and spatial CSS.The project uses and state-of-arts of two-way CSS and spatial CSS were introduced in this paper.Some problems needing attention were also discussed.
2009, 39(11): 100-103.
doi: 10.13204/j.gyjz200911023
Abstract:
Based on the research on the joints and whole frame seismic performances of precast comcrete structures both at home and abroad,and combined with the test and analyses of new type of connection of concrete frame structuresprestressed assembling frame,then it is proposed that the developing trend and study direction of actual projects of precast concrete structures in future
Based on the research on the joints and whole frame seismic performances of precast comcrete structures both at home and abroad,and combined with the test and analyses of new type of connection of concrete frame structuresprestressed assembling frame,then it is proposed that the developing trend and study direction of actual projects of precast concrete structures in future
2009, 39(11): 104-107.
doi: 10.13204/j.gyjz200911024
Abstract:
Based on characteristics of L-shaped short composite column of concrete-filled square steel tubes(LCSC),research on calculation method and ultimate load-carrying capacity under axial compression for the special-shaped column is done by three methods: superposition theory,finite element analysis and axial compression test.One LCSC specimen is designed and manufactured with depthwidth ratio is 4 for mono column.For the LCSC specimen,ultimate load attained by superposition theory is 3 720 kN;ultimate load is 3 518 kN according to finite elements analysis with shell element,solid element and contact elements;and ultimate load got from axial compression experiment is 3 975 kN.The Results of theoretical calculation,finite elements analysis and axial compression test all show that ultimate loads from three methods accord with each other well.The ultimate load-carrying capacity of LCSC is acquired,and the feasibility of calculation in superposition theory for LCSC is proved.
Based on characteristics of L-shaped short composite column of concrete-filled square steel tubes(LCSC),research on calculation method and ultimate load-carrying capacity under axial compression for the special-shaped column is done by three methods: superposition theory,finite element analysis and axial compression test.One LCSC specimen is designed and manufactured with depthwidth ratio is 4 for mono column.For the LCSC specimen,ultimate load attained by superposition theory is 3 720 kN;ultimate load is 3 518 kN according to finite elements analysis with shell element,solid element and contact elements;and ultimate load got from axial compression experiment is 3 975 kN.The Results of theoretical calculation,finite elements analysis and axial compression test all show that ultimate loads from three methods accord with each other well.The ultimate load-carrying capacity of LCSC is acquired,and the feasibility of calculation in superposition theory for LCSC is proved.
2009, 39(11): 108-112.
doi: 10.13204/j.gyjz200911025
Abstract:
Experiment on bearing capacity of 48 Q460 high strength angle steel for compression members attached by one leg was carried out,the results of mechanical behavior and deformation for specimens were analyzed.The experiment result shows: the bending deflection of the angle occurred in a direction parallel to the connected leg,meanwhile,the twisting deformation occurred in a longitudinal direction of specimen.Most of small slenderness members were controlled by local buckling,and large members were controlled by overall buckling.Then compared with the experimental results and American Design of Latticed Steel Transmission Structures ASCE 101997 results,the results show experiment results are slightly larger than American ASCE 101997 results.Therefore,Q460 high-strength equal angle steel compression members attached by one leg can be designed using ASCE 101997,and the design is in favor of a security.
Experiment on bearing capacity of 48 Q460 high strength angle steel for compression members attached by one leg was carried out,the results of mechanical behavior and deformation for specimens were analyzed.The experiment result shows: the bending deflection of the angle occurred in a direction parallel to the connected leg,meanwhile,the twisting deformation occurred in a longitudinal direction of specimen.Most of small slenderness members were controlled by local buckling,and large members were controlled by overall buckling.Then compared with the experimental results and American Design of Latticed Steel Transmission Structures ASCE 101997 results,the results show experiment results are slightly larger than American ASCE 101997 results.Therefore,Q460 high-strength equal angle steel compression members attached by one leg can be designed using ASCE 101997,and the design is in favor of a security.
TEST & ANALYSIS OF IN-PLANE FLEXURAL BEHAVIORS OF STRENGTHENED GLASS RIBS FOR ALL-GLASS CURTAIN WALL
2009, 39(11): 113-117.
doi: 10.13204/j.gyjz200911026
Abstract:
Nine simply supported glass ribs are tested under in-plane bending,among which,three ribs are strengthened with tempered glass sheets and three ribs are strengthened with stainless steel sheets.The failure modes and the mechanical behaviors of the ribs are compared and analyzed.It can be found that the P- curves of the ribs are always linear and brittle failures usually occur,no matter if they are strengthened or not.The flexural capacity and the deformability of the rib can be effectively improved if the rib is strengthened using tempered glass or stainless steel.The strained section of the ribs remains plane but the strain lag will occur in the tempered glass sheets or the stainless steel sheets,which should be considered in the design of the strengthened glass rib.
Nine simply supported glass ribs are tested under in-plane bending,among which,three ribs are strengthened with tempered glass sheets and three ribs are strengthened with stainless steel sheets.The failure modes and the mechanical behaviors of the ribs are compared and analyzed.It can be found that the P- curves of the ribs are always linear and brittle failures usually occur,no matter if they are strengthened or not.The flexural capacity and the deformability of the rib can be effectively improved if the rib is strengthened using tempered glass or stainless steel.The strained section of the ribs remains plane but the strain lag will occur in the tempered glass sheets or the stainless steel sheets,which should be considered in the design of the strengthened glass rib.
2009, 39(11): 118-121.
doi: 10.13204/j.gyjz200911027
Abstract:
This paper presents the seismic retrofit of a 4-story reinforced concrete frame with buckling-restrained braces(BRB),including comparison the seismic effects between the original structure and the retrofitted structure using response spectra analysis and history analysis under the frequent earthquakes and the basic earthquakes.The results indicate that: the BRBs can improve aseismatic capacity of the structure;when subjected to the frequent earthquakes,the BRBs are in elastic state,providing the stiffness for the main structure;when subjected to the basic earthquakes,the BRBs in the structure are in non-lined state,providing the energy-dissipation capacity.
This paper presents the seismic retrofit of a 4-story reinforced concrete frame with buckling-restrained braces(BRB),including comparison the seismic effects between the original structure and the retrofitted structure using response spectra analysis and history analysis under the frequent earthquakes and the basic earthquakes.The results indicate that: the BRBs can improve aseismatic capacity of the structure;when subjected to the frequent earthquakes,the BRBs are in elastic state,providing the stiffness for the main structure;when subjected to the basic earthquakes,the BRBs in the structure are in non-lined state,providing the energy-dissipation capacity.
2009, 39(11): 122-125.
doi: 10.13204/j.gyjz200911028
Abstract:
Adopting the FEM,calculation and analysis have been undergone for ground vertical deformation,shear force within foundation slab and distribution of bending moment on the basis of four modes that are raft on the natural foundation of existing building,piling surrounding raft basis,soft soil grouting and lateral reinforcement grouting substitution separately.Under the calculated circumstance,the way of lateral reinforcement grouting substitution is able to abate both the structure's settlement,accounting for only half of the natural one,and contemporarily additional stress within the foundation slab,whose most shear force and bending moment are decreased by over 54% and 47% respectively compared with reinforced piling around the structure periphery.Furthermore,the strengthened foundation's mechanical property is closer to that of the natural one under which most structures are designed,favoring the base work and avoiding excessive stress adjustment inside the foundation.In addition,the construction of strengthening the foundation by the technique is carried out outdoors for the purpose of overall stabilization without influencing either the normal life of citizens on the ground floor or factory' work.
Adopting the FEM,calculation and analysis have been undergone for ground vertical deformation,shear force within foundation slab and distribution of bending moment on the basis of four modes that are raft on the natural foundation of existing building,piling surrounding raft basis,soft soil grouting and lateral reinforcement grouting substitution separately.Under the calculated circumstance,the way of lateral reinforcement grouting substitution is able to abate both the structure's settlement,accounting for only half of the natural one,and contemporarily additional stress within the foundation slab,whose most shear force and bending moment are decreased by over 54% and 47% respectively compared with reinforced piling around the structure periphery.Furthermore,the strengthened foundation's mechanical property is closer to that of the natural one under which most structures are designed,favoring the base work and avoiding excessive stress adjustment inside the foundation.In addition,the construction of strengthening the foundation by the technique is carried out outdoors for the purpose of overall stabilization without influencing either the normal life of citizens on the ground floor or factory' work.
2009, 39(11): 126-128.
doi: 10.13204/j.gyjz200911029
Abstract:
It was explored a new design and construction method of the corbel between the old column and the new beam for a reform project in Beijing.Each ascendancy of the anchoring and pre-stressing technology was applied in this project.The experience of the design and construction can give some advice to the similar project
It was explored a new design and construction method of the corbel between the old column and the new beam for a reform project in Beijing.Each ascendancy of the anchoring and pre-stressing technology was applied in this project.The experience of the design and construction can give some advice to the similar project
2009, 39(11): 129-131.
doi: 10.13204/j.gyjz200911030
Abstract:
This thesis is mainly dicussing about the design of the new-type and diversified gymnasium with intensive function and three dimensional combination,through associating with the practice of the project of the gymnasium of Changsha Helong Sports School.It focuses on such aspects as the imagination,the organization of functional space,the solution to the technical problems and so on.
This thesis is mainly dicussing about the design of the new-type and diversified gymnasium with intensive function and three dimensional combination,through associating with the practice of the project of the gymnasium of Changsha Helong Sports School.It focuses on such aspects as the imagination,the organization of functional space,the solution to the technical problems and so on.
2009, 39(11): 132-136,89.
doi: 10.13204/j.gyjz200911031
Abstract:
According to the condition of the natatorium with double-floor swimming pools in Harbin Institute of Technology,the standards for controlling crack and deformation of prestressed frame supporting the match pool is given.The process of arranging prestressing reinforcements and non-prestressed reinforcements in frame beam and frame column is introduced in detail.In order to avoid colliding of reinforcements in frame beam and frame column and ensure the safety of local compression and joint,the distribution of reinforcements and the measures for tension and anchorage are highlighted.Anchorage technique for prestressing reinforcements in frame column is presented.The principle of grouting and selecting of grout for frame beam and frame column are given.
According to the condition of the natatorium with double-floor swimming pools in Harbin Institute of Technology,the standards for controlling crack and deformation of prestressed frame supporting the match pool is given.The process of arranging prestressing reinforcements and non-prestressed reinforcements in frame beam and frame column is introduced in detail.In order to avoid colliding of reinforcements in frame beam and frame column and ensure the safety of local compression and joint,the distribution of reinforcements and the measures for tension and anchorage are highlighted.Anchorage technique for prestressing reinforcements in frame column is presented.The principle of grouting and selecting of grout for frame beam and frame column are given.
