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2008 Vol. 38, No. 7
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2008, 38(7): 1-5,15.
doi: 10.13204/j.gyjz200807001
Abstract:
Displacement-based seismic design method has been recognized as one of the most efficient way to realize the purpose of performance-based seismic design in current stage and therefore has attracted extensive attentions from many researchers around the world.The background of the origination of this method,the classification,and its development in recent years are summarized.Then the review is focused on the estimation of seismic displacement demands in two aspects,nonlinear seismic displacement spectrum and pushover analysis procedure.At last,the existing problems are analyzed and the further work needed in this field is proposed accordingly.
Displacement-based seismic design method has been recognized as one of the most efficient way to realize the purpose of performance-based seismic design in current stage and therefore has attracted extensive attentions from many researchers around the world.The background of the origination of this method,the classification,and its development in recent years are summarized.Then the review is focused on the estimation of seismic displacement demands in two aspects,nonlinear seismic displacement spectrum and pushover analysis procedure.At last,the existing problems are analyzed and the further work needed in this field is proposed accordingly.
2008, 38(7): 6-10,53.
doi: 10.13204/j.gyjz200807002
Abstract:
The natural periods and corresponding modes of structure are obtained by free vibration analysis.Based on the periods,the equivalent displacement of single-degree-of-freedom system for each mode is deduced by displacement response spectra,and the structural lateral elastic displacement of each mode could be determined by equivalence principle.So the structural lateral elastic displacement can be obtained by SRSS rule.Then,based on the story drift ratio limits,the structural target lateral displacement of each mode could be determined,and the shear in each story is obtained by SRSS rule too,the direct displacement-based seismic design(DDBSD) method of high-rise buildings considering higher mode effects is realized.The paper illustrates the application of the proposed procedure with an example and attempts to prove its feasibility by elasto-plastic time-history analysis.It provides a valuable thought for DDBSD method of high-rise buildings.
The natural periods and corresponding modes of structure are obtained by free vibration analysis.Based on the periods,the equivalent displacement of single-degree-of-freedom system for each mode is deduced by displacement response spectra,and the structural lateral elastic displacement of each mode could be determined by equivalence principle.So the structural lateral elastic displacement can be obtained by SRSS rule.Then,based on the story drift ratio limits,the structural target lateral displacement of each mode could be determined,and the shear in each story is obtained by SRSS rule too,the direct displacement-based seismic design(DDBSD) method of high-rise buildings considering higher mode effects is realized.The paper illustrates the application of the proposed procedure with an example and attempts to prove its feasibility by elasto-plastic time-history analysis.It provides a valuable thought for DDBSD method of high-rise buildings.
2008, 38(7): 11-15.
doi: 10.13204/j.gyjz200807003
Abstract:
Based on the theoretical studies of structural control,it is proposed that the themal-insulating roof of a multistory building be used as TMD system to reduce seismic response,and further studied the structural design of the thermal-insulating roof used as TMD system.A numerical simulation is used to test the feasibility and praticality of this disign.
Based on the theoretical studies of structural control,it is proposed that the themal-insulating roof of a multistory building be used as TMD system to reduce seismic response,and further studied the structural design of the thermal-insulating roof used as TMD system.A numerical simulation is used to test the feasibility and praticality of this disign.
2008, 38(7): 16-18,29.
doi: 10.13204/j.gyjz200807004
Abstract:
The main building for a thermal power plant usually has shear wall only in longitudinal direction,and in 0.2Q_0 adjustment,the design software always adjust section internal forces of all the beams connected with the frame column,which exaggerates section internal forces of lateral beams,causing unnecessary conservativeness.It is proposed twice design calculation should be done for this kind of structure.In the first step,the structure is designed according to frame-shear wall system.Then the second step calculation and design are carried out,in this case the structure is designed being as frame system.It is suggested to use the calculation results from second and first step design for lateral frame beams and the other components respectively.
The main building for a thermal power plant usually has shear wall only in longitudinal direction,and in 0.2Q_0 adjustment,the design software always adjust section internal forces of all the beams connected with the frame column,which exaggerates section internal forces of lateral beams,causing unnecessary conservativeness.It is proposed twice design calculation should be done for this kind of structure.In the first step,the structure is designed according to frame-shear wall system.Then the second step calculation and design are carried out,in this case the structure is designed being as frame system.It is suggested to use the calculation results from second and first step design for lateral frame beams and the other components respectively.
2008, 38(7): 19-22.
doi: 10.13204/j.gyjz200807005
Abstract:
A simplified method is used for evaluating the reliablity for the existing strucural system,which is based on the analytical hierarchy process and the first-order second-moment method.Combination of the reliability of members by different weighing parameters(ratio of load vs.resistance with some modifications) is defined as the storey reliability.The minimum value of the storey reliability is defined as the reliability of the whole structural system.The shear failure model of wall is the main fault model of wall member under earthquake,so the benefit function is defined as the shear resistant capacity of the wall minus the corresponding earthquake reaction.The formula of the shear resistant capacity of wall in the current design code can be used here.Engineer case is presented here to demonstrate this method for aseismic reliability of the existing masonry structures.
A simplified method is used for evaluating the reliablity for the existing strucural system,which is based on the analytical hierarchy process and the first-order second-moment method.Combination of the reliability of members by different weighing parameters(ratio of load vs.resistance with some modifications) is defined as the storey reliability.The minimum value of the storey reliability is defined as the reliability of the whole structural system.The shear failure model of wall is the main fault model of wall member under earthquake,so the benefit function is defined as the shear resistant capacity of the wall minus the corresponding earthquake reaction.The formula of the shear resistant capacity of wall in the current design code can be used here.Engineer case is presented here to demonstrate this method for aseismic reliability of the existing masonry structures.
2008, 38(7): 23-29.
doi: 10.13204/j.gyjz200807006
Abstract:
It is introduced 2 new semiactive control devices for coupled buildings.The equations of motion of coupled buildings with the proposed control devices are established herein.Furthermore,a new semiactive control algorithm,which can be used for all switching-type semiactive control systems,is put forward in this paper to derive the control laws of the proposed semiactive control systems.Numerical simulation is carried out to investigate the performance of the proposed control devices and the new semiactive control algorithm,and study the effect of the dynamical parameters of coupled buildings on the control effectiveness.Results show that the newly proposed control devices and algorithm are very effective to increase the safety and living comfort of the coupled buildings subject to earthquakes.The semiactive variable stiffness and damping control device outperforms the semiactive variable stiffness control as the result of the presence of auxiliary damping in this device.
It is introduced 2 new semiactive control devices for coupled buildings.The equations of motion of coupled buildings with the proposed control devices are established herein.Furthermore,a new semiactive control algorithm,which can be used for all switching-type semiactive control systems,is put forward in this paper to derive the control laws of the proposed semiactive control systems.Numerical simulation is carried out to investigate the performance of the proposed control devices and the new semiactive control algorithm,and study the effect of the dynamical parameters of coupled buildings on the control effectiveness.Results show that the newly proposed control devices and algorithm are very effective to increase the safety and living comfort of the coupled buildings subject to earthquakes.The semiactive variable stiffness and damping control device outperforms the semiactive variable stiffness control as the result of the presence of auxiliary damping in this device.
2008, 38(7): 30-33.
doi: 10.13204/j.gyjz200807007
Abstract:
Based on a shaking table experiment of 1∶25 scale irregular frame-shearwall structure model,the dynamic characteristics,seismic responses in elastic and elastic-plastic phases,and destructive forms of the structure were studied.It was observed that cracks developed with earthquake wave acceleration increasing,but no severe crack is developed in the structure during the experiment,the stiffness of the structure is weakened quickly.In the seismic responses caused by artificial wave,site wave and El Centro wave,that caused by the artificial wave is the most intense one.Torsion of the structure is heavier beacause of declination between center of mass and siffness.So stiffness of tube shearwall should be reinforced to improve its ductileness.
Based on a shaking table experiment of 1∶25 scale irregular frame-shearwall structure model,the dynamic characteristics,seismic responses in elastic and elastic-plastic phases,and destructive forms of the structure were studied.It was observed that cracks developed with earthquake wave acceleration increasing,but no severe crack is developed in the structure during the experiment,the stiffness of the structure is weakened quickly.In the seismic responses caused by artificial wave,site wave and El Centro wave,that caused by the artificial wave is the most intense one.Torsion of the structure is heavier beacause of declination between center of mass and siffness.So stiffness of tube shearwall should be reinforced to improve its ductileness.
2008, 38(7): 34-37.
doi: 10.13204/j.gyjz200807008
Abstract:
It is very important to know the shaking table tests properly before testing.Some improper practice and the development trends of the shaking table tests are also described in this paper.
It is very important to know the shaking table tests properly before testing.Some improper practice and the development trends of the shaking table tests are also described in this paper.
2008, 38(7): 38-40.
doi: 10.13204/j.gyjz200807009
Abstract:
How to control the torsional response of structures under earthquake action is a problem frequently occurred in seismic design.The main objective of this paper is to present a reasonable numerical method for the time-history analysis of structures with viscous dampers,particularly those with irregular configurations,the supplemental damping matrix of structures with viscous dampers is incorporated into a general nonlinear dynamic analysis program,which can consider the effects of deformation of local floor and the propagation direction of earthquake excitations.Example is provided to validate the dynamic analysis method and observe the seismic mitigation effect of viscous dampers.The inner forces and deformation of structural members and viscous dampers can be given.
How to control the torsional response of structures under earthquake action is a problem frequently occurred in seismic design.The main objective of this paper is to present a reasonable numerical method for the time-history analysis of structures with viscous dampers,particularly those with irregular configurations,the supplemental damping matrix of structures with viscous dampers is incorporated into a general nonlinear dynamic analysis program,which can consider the effects of deformation of local floor and the propagation direction of earthquake excitations.Example is provided to validate the dynamic analysis method and observe the seismic mitigation effect of viscous dampers.The inner forces and deformation of structural members and viscous dampers can be given.
2008, 38(7): 41-44,49.
doi: 10.13204/j.gyjz200807010
Abstract:
It is introduced a new type of shearing lead damper,the shearing lead damper has simple structure and low production cost,performance tests showed that this damper can provide the similar hysteresis curve with that of conventional shearing lead damper.This new type of shearing lead dampers are used in mill buildings for a thermal power plant to reduce earthquake effect.Under the disturbance by small earthquakes,the damper can provide the structure with the additional 2% damping ratio,which was verified by non-linear analysis of time-hislory;in strong earthquake,through Pushover analysis,it was showed that the structure with the dampers has a good seismic performance,which may also be used in the post-earthquake.
It is introduced a new type of shearing lead damper,the shearing lead damper has simple structure and low production cost,performance tests showed that this damper can provide the similar hysteresis curve with that of conventional shearing lead damper.This new type of shearing lead dampers are used in mill buildings for a thermal power plant to reduce earthquake effect.Under the disturbance by small earthquakes,the damper can provide the structure with the additional 2% damping ratio,which was verified by non-linear analysis of time-hislory;in strong earthquake,through Pushover analysis,it was showed that the structure with the dampers has a good seismic performance,which may also be used in the post-earthquake.
2008, 38(7): 45-49.
doi: 10.13204/j.gyjz200807011
Abstract:
Through researching the works of Thomas Herzog who is the famous ecological architect,it has been brought forward that some basic ecological design principles,which are expressed as construction of buffer space,harmony between lighting and shading,organization of ventilation without mechanism,structure of alterable interfaces.Furthermore,under the direction of the principles,it is also expounded that some detailed eco-design tactics.
Through researching the works of Thomas Herzog who is the famous ecological architect,it has been brought forward that some basic ecological design principles,which are expressed as construction of buffer space,harmony between lighting and shading,organization of ventilation without mechanism,structure of alterable interfaces.Furthermore,under the direction of the principles,it is also expounded that some detailed eco-design tactics.
2008, 38(7): 50-53.
doi: 10.13204/j.gyjz200807012
Abstract:
The development of economy and energy resources exploitation make the construction of small towns on Loess Plateau have the high-speed and great-leap-forward progress.The local residents' life contents and life style,the functional structure pattern of the towns,monomer building form are all assimilated by the outside unitary mode.Traditional local-style dwelling houses in which local people depend on for existence for hundreds of yearsthe cave dwelling is abandoned in the urban renewal process gradually because of the influence of some factors.This leads to the fracture of the culture context of urban history in this area,and loss of its own unique characteristics and regional cognition.As a result,people and the environment are not in harmony.It is analyzed the development of cave dwelling,its current situation and all kinds of the existing problems,accordingly,the preliminary strategy is also proposed.
The development of economy and energy resources exploitation make the construction of small towns on Loess Plateau have the high-speed and great-leap-forward progress.The local residents' life contents and life style,the functional structure pattern of the towns,monomer building form are all assimilated by the outside unitary mode.Traditional local-style dwelling houses in which local people depend on for existence for hundreds of yearsthe cave dwelling is abandoned in the urban renewal process gradually because of the influence of some factors.This leads to the fracture of the culture context of urban history in this area,and loss of its own unique characteristics and regional cognition.As a result,people and the environment are not in harmony.It is analyzed the development of cave dwelling,its current situation and all kinds of the existing problems,accordingly,the preliminary strategy is also proposed.
2008, 38(7): 54-57,74.
doi: 10.13204/j.gyjz200807013
Abstract:
Based on the characteristics of ground symmetrical failure,the discontinuous stress field and velocity field of the soil mass are constructed.The character of discontinuous line of stress and velocity,the stress field are analyzed.By upper and lower bound theorems,the model of calculation and the method for bearing capacity are got.The stress field and the corresponding mobile field are got by the numerical calculation to solve three kinds of boundary value problems.The stress field satisfied with all velocity boundary is found.The rigorous solution of bearing capacity considering shear strength of soil on sides of foundation is obtained.The computation results show that the approach to solve the limit equilibrium problem is available.
Based on the characteristics of ground symmetrical failure,the discontinuous stress field and velocity field of the soil mass are constructed.The character of discontinuous line of stress and velocity,the stress field are analyzed.By upper and lower bound theorems,the model of calculation and the method for bearing capacity are got.The stress field and the corresponding mobile field are got by the numerical calculation to solve three kinds of boundary value problems.The stress field satisfied with all velocity boundary is found.The rigorous solution of bearing capacity considering shear strength of soil on sides of foundation is obtained.The computation results show that the approach to solve the limit equilibrium problem is available.
2008, 38(7): 58-61,134.
doi: 10.13204/j.gyjz200807014
Abstract:
Starting from the governing equations of Biot three dimensional consolidation problem and introducing the displacement functions,the 8 order transfer matrix between z=z and z=0 is obtained by taking the Laplace transform with respect to time(t) and the double Fourier transform with respect to coordinate x and y.According to the continuity conditions between adjacent layers and the horizon plane of well point pump and boundary conditions,the actual solutions of multi-layered soil due to pumping from well point are obtained by using the transfer matrix properties and the techniques of the Laplace-Fourier inverse transforms.Numerical results show that the surface settlement of saturated multi-layered soil increases with the increase of time.
Starting from the governing equations of Biot three dimensional consolidation problem and introducing the displacement functions,the 8 order transfer matrix between z=z and z=0 is obtained by taking the Laplace transform with respect to time(t) and the double Fourier transform with respect to coordinate x and y.According to the continuity conditions between adjacent layers and the horizon plane of well point pump and boundary conditions,the actual solutions of multi-layered soil due to pumping from well point are obtained by using the transfer matrix properties and the techniques of the Laplace-Fourier inverse transforms.Numerical results show that the surface settlement of saturated multi-layered soil increases with the increase of time.
2008, 38(7): 62-66.
doi: 10.13204/j.gyjz200807015
Abstract:
Spherical and ellipsoidal surfaces and also the non-uniform rational B-spline(NURBS) are adopted to simulate 3D sliding bodies of slopes;the mixed particle Swarm Optimization algorithm is used to locate the critical sliding body and its corresponding factor of safety given by simplified three-dimensional Janbu method.The effects of different simulating procedures on the results are studied for one typical soil slope.In addition,it is analyzed time consumption of the number of changing points in NURBS and its effect on the results.
Spherical and ellipsoidal surfaces and also the non-uniform rational B-spline(NURBS) are adopted to simulate 3D sliding bodies of slopes;the mixed particle Swarm Optimization algorithm is used to locate the critical sliding body and its corresponding factor of safety given by simplified three-dimensional Janbu method.The effects of different simulating procedures on the results are studied for one typical soil slope.In addition,it is analyzed time consumption of the number of changing points in NURBS and its effect on the results.
2008, 38(7): 67-70.
doi: 10.13204/j.gyjz200807016
Abstract:
By improved experiment,the swelling pressure test of expansive soils has been carried out with respect to initial variations in dry densities,water contents and vertical pressures.Correlation of swelling pressures to percents swell,dry densities,water contents and vertical pressures have been studied.Results indicate that the swelling pressure vs.percent swell can be taken as linearly related up to about a swelling pressure of 800 kPa;the swelling pressures increase with increase in initial densities while decrease with increase in water contents and vertical pressures.By means of regression analysis,both the swell pressure-initial density relationship and the swell pressure-initial water content relationship are approximately linear,while the swelling pressure-vertical pressure relation is a semi-logarithm linear one.The most sensitive factor to the changes of swelling pressure is the dry density,then the water content and the last the vertical pressure.
By improved experiment,the swelling pressure test of expansive soils has been carried out with respect to initial variations in dry densities,water contents and vertical pressures.Correlation of swelling pressures to percents swell,dry densities,water contents and vertical pressures have been studied.Results indicate that the swelling pressure vs.percent swell can be taken as linearly related up to about a swelling pressure of 800 kPa;the swelling pressures increase with increase in initial densities while decrease with increase in water contents and vertical pressures.By means of regression analysis,both the swell pressure-initial density relationship and the swell pressure-initial water content relationship are approximately linear,while the swelling pressure-vertical pressure relation is a semi-logarithm linear one.The most sensitive factor to the changes of swelling pressure is the dry density,then the water content and the last the vertical pressure.
2008, 38(7): 71-74.
doi: 10.13204/j.gyjz200807017
Abstract:
Based on tests of 27 pull-out specimens and 16 beam specimens,the bond-slip relation and bond strength between AFRP bars and concrete are discussed.And according to other references of the experimental result,the simplification of local bond-slip constitutive relation and a calculation formula of anchorage length of AFRP bars with pullout failure are obtained.
Based on tests of 27 pull-out specimens and 16 beam specimens,the bond-slip relation and bond strength between AFRP bars and concrete are discussed.And according to other references of the experimental result,the simplification of local bond-slip constitutive relation and a calculation formula of anchorage length of AFRP bars with pullout failure are obtained.
2008, 38(7): 75-78.
doi: 10.13204/j.gyjz200807018
Abstract:
Based on two sets of specimens,the compressive behaviors of N-type block masonry were investigated.Through these tests,the failure mode and the failure mechanism were studied.Test results show that the average compressive strength of N-type block masonry is increased by 30%～52% as compared to the common concrete masonry.The main reason for the strength rising is the full-alignment of web-shells in N-type block masonry prisms.Recommended formulas for calculating average compressive strength and modulus of elasticity is presented and the calculated results by the formulas are in good agreement with the test results.
Based on two sets of specimens,the compressive behaviors of N-type block masonry were investigated.Through these tests,the failure mode and the failure mechanism were studied.Test results show that the average compressive strength of N-type block masonry is increased by 30%～52% as compared to the common concrete masonry.The main reason for the strength rising is the full-alignment of web-shells in N-type block masonry prisms.Recommended formulas for calculating average compressive strength and modulus of elasticity is presented and the calculated results by the formulas are in good agreement with the test results.
2008, 38(7): 79-81,130.
doi: 10.13204/j.gyjz200807019
Abstract:
The mass concrete cracking that attributed to temperature change is a very intractability problem in construction,many studies were made,and some progress in temperature control and crack restriction was made.It was investigated the construction process of the Shenzhen side-connection item of Shenzhen-Hong Kong West Channel Project,and analyzed the cause for the temperature crack,put forward some relevant control measures,it came out a very good result in the project.
The mass concrete cracking that attributed to temperature change is a very intractability problem in construction,many studies were made,and some progress in temperature control and crack restriction was made.It was investigated the construction process of the Shenzhen side-connection item of Shenzhen-Hong Kong West Channel Project,and analyzed the cause for the temperature crack,put forward some relevant control measures,it came out a very good result in the project.
2008, 38(7): 82-84,123.
doi: 10.13204/j.gyjz200807020
Abstract:
The thawing of ice and snow timely is a difficult problem all over the world.The using deicing salts is the most common method.Based on analysing advantages and disadvantages of using deicing salts,it is emphasized that using deicing salts has corosive harms to infrastructures and affects enviroment.Finally a series of ineasures to reduce these harms are proposed
The thawing of ice and snow timely is a difficult problem all over the world.The using deicing salts is the most common method.Based on analysing advantages and disadvantages of using deicing salts,it is emphasized that using deicing salts has corosive harms to infrastructures and affects enviroment.Finally a series of ineasures to reduce these harms are proposed
2008, 38(7): 85-88.
doi: 10.13204/j.gyjz200807021
Abstract:
A deep research on welding techniques of Q46OE-Z35 thick steel plate is carried out from both experimental study and project use.Whose mating construction techniques are summarized,which may offer useful experience in revision of relevant specifications and engineering practice in the future.
A deep research on welding techniques of Q46OE-Z35 thick steel plate is carried out from both experimental study and project use.Whose mating construction techniques are summarized,which may offer useful experience in revision of relevant specifications and engineering practice in the future.
2008, 38(7): 89-91,119.
doi: 10.13204/j.gyjz200807022
Abstract:
In order to study force performance of a new column,it is described the test results of nine stub-columns with partially encased welded H-section steel.The test studies the effects of steel ratio,width-thickness ratio of flange and space of horizontal bar on ultimate strength of short column.It has been found out by analysis that on condition of different steel ratios,the ultimate bearing capacity of a column is affected directly by the bearing capacity of PEC short column under axial load and its influencing factors,as well as steel ratio.
In order to study force performance of a new column,it is described the test results of nine stub-columns with partially encased welded H-section steel.The test studies the effects of steel ratio,width-thickness ratio of flange and space of horizontal bar on ultimate strength of short column.It has been found out by analysis that on condition of different steel ratios,the ultimate bearing capacity of a column is affected directly by the bearing capacity of PEC short column under axial load and its influencing factors,as well as steel ratio.
2008, 38(7): 92-94,127.
doi: 10.13204/j.gyjz200807023
Abstract:
In this paper,a new type braced frame structure with a slip device is presented.Three specimens which have different angle of the brace are designed for low cyclic reversed lateral loading tests to verify the energy-dissipation capacity of the new type braced frame structure.The seismic energy dissipated ability between the new and normal type braced frame structures are compared based on the experimental and calculated results.The test result shows that the new type brace with the angle of 45 degree possesses excellent energy dissipation capacity.
In this paper,a new type braced frame structure with a slip device is presented.Three specimens which have different angle of the brace are designed for low cyclic reversed lateral loading tests to verify the energy-dissipation capacity of the new type braced frame structure.The seismic energy dissipated ability between the new and normal type braced frame structures are compared based on the experimental and calculated results.The test result shows that the new type brace with the angle of 45 degree possesses excellent energy dissipation capacity.
2008, 38(7): 95-97.
doi: 10.13204/j.gyjz200807024
Abstract:
To promote the practicing of steel tube and steel-reinforced concrete composite member in the projects,the flexural bearing capacity of H-shaped section and cross steel section is discussed in this article,and limit balance method is used to calculate its bending capacity.Moreover,the accuracy of the formula has been verified.For benefiting to its application in the projects,setting out from economy,it is compared the flexural bearing capacity between two sections.From this,it has been found out that the H-shaped steel section has strong flexural bearing capacity in the same amount of steel.It's offering a theoretic basis to the design.
To promote the practicing of steel tube and steel-reinforced concrete composite member in the projects,the flexural bearing capacity of H-shaped section and cross steel section is discussed in this article,and limit balance method is used to calculate its bending capacity.Moreover,the accuracy of the formula has been verified.For benefiting to its application in the projects,setting out from economy,it is compared the flexural bearing capacity between two sections.From this,it has been found out that the H-shaped steel section has strong flexural bearing capacity in the same amount of steel.It's offering a theoretic basis to the design.
2008, 38(7): 98-102.
doi: 10.13204/j.gyjz200807025
Abstract:
A theoretical study is carried out on the current design approach of embedded steel column bases.The load transfer within embedded bases is analyzed.Because of the studs,part of the axial load is transferred from steel to foundation concrete.An analytical solution is presented for the axial load in the concrete.Through calculated examples it is found that the axial force in the concrete is 25%～35% of the total axial force of the column.Based on this finding,the design methods of shear stud and the column base plate are proposed.Based on the shear and bending moment transfer of the embedded steel column bases,the strength check is proposed,and for side columns and corner columns,horizontal U-rebars are proposed to prevent horizontal punch shear failure of concrete,method for determining the area of the U-rebars is presented.Embedded steel column bases have inadequate vertical punch shear strength below.It is presented a method for avoiding this punch shear failure by adding horizontal short steel beams at the base.
A theoretical study is carried out on the current design approach of embedded steel column bases.The load transfer within embedded bases is analyzed.Because of the studs,part of the axial load is transferred from steel to foundation concrete.An analytical solution is presented for the axial load in the concrete.Through calculated examples it is found that the axial force in the concrete is 25%～35% of the total axial force of the column.Based on this finding,the design methods of shear stud and the column base plate are proposed.Based on the shear and bending moment transfer of the embedded steel column bases,the strength check is proposed,and for side columns and corner columns,horizontal U-rebars are proposed to prevent horizontal punch shear failure of concrete,method for determining the area of the U-rebars is presented.Embedded steel column bases have inadequate vertical punch shear strength below.It is presented a method for avoiding this punch shear failure by adding horizontal short steel beams at the base.
2008, 38(7): 103-106.
doi: 10.13204/j.gyjz200807026
Abstract:
General rule for performance-based seismic design of buildings(General Rule),a probationary standard,is very important in the direction for modification of the current seismic code,and is of great promise for application to engineering.Because of the influence of the design custom and the lag of relevant software,ordinary designers are unfamiliar with the design system of General Rule.The principle of General Rule was introduced.After this,the way of calculating earthquake action was analyzed,and the design procedure was summarized,then the usage of popular design software applied the method of General Rule was discussed.Finally,example was analyzed.This paper may be implications for the application and popularization of performance based seismic design employed General Rule.
General rule for performance-based seismic design of buildings(General Rule),a probationary standard,is very important in the direction for modification of the current seismic code,and is of great promise for application to engineering.Because of the influence of the design custom and the lag of relevant software,ordinary designers are unfamiliar with the design system of General Rule.The principle of General Rule was introduced.After this,the way of calculating earthquake action was analyzed,and the design procedure was summarized,then the usage of popular design software applied the method of General Rule was discussed.Finally,example was analyzed.This paper may be implications for the application and popularization of performance based seismic design employed General Rule.
2008, 38(7): 107-112.
doi: 10.13204/j.gyjz200807027
Abstract:
The full play to high-strength and high elasticity of CFRP sheets can be given by strengthening technology with prestressed CFRP sheets,which can increase remarkably fatigue life of a rein-forced concrete beam.It is analyzed the fatigue life of prestressed CFRP sheets under fatigue load,using local stress-strain method.The key parameters are determined by the test results,based on which practical calculation method of its fatigue life is also proposed.This method is more rational as compared to that in current code,which may provide a reference for subsequently researching fatigue theory and working out codes.
The full play to high-strength and high elasticity of CFRP sheets can be given by strengthening technology with prestressed CFRP sheets,which can increase remarkably fatigue life of a rein-forced concrete beam.It is analyzed the fatigue life of prestressed CFRP sheets under fatigue load,using local stress-strain method.The key parameters are determined by the test results,based on which practical calculation method of its fatigue life is also proposed.This method is more rational as compared to that in current code,which may provide a reference for subsequently researching fatigue theory and working out codes.
2008, 38(7): 113-115.
doi: 10.13204/j.gyjz200807028
Abstract:
The structural protection of the lithoid cultural relics is a difficult problem for destroys of wind erosion and man-made factors.The bend-resisting behavior of lithoid cultural relics reinforced with CFRP is studied through the test combined with the protective project of Shao Hao decorated archways.The destroyed mode,carrying capacity and rigidity are contrasted and analyzed.The destroyed mode of lithoid cultural relics is changed obviously from right section brittle destroy to oblique section ductile destroy.Its bend-resisting capacity and deformability are improved obviously.The tests results revealed that the bend-resisting capacity of lithoid cultural relics reinforced with CFRP can be enhanced greatly.
The structural protection of the lithoid cultural relics is a difficult problem for destroys of wind erosion and man-made factors.The bend-resisting behavior of lithoid cultural relics reinforced with CFRP is studied through the test combined with the protective project of Shao Hao decorated archways.The destroyed mode,carrying capacity and rigidity are contrasted and analyzed.The destroyed mode of lithoid cultural relics is changed obviously from right section brittle destroy to oblique section ductile destroy.Its bend-resisting capacity and deformability are improved obviously.The tests results revealed that the bend-resisting capacity of lithoid cultural relics reinforced with CFRP can be enhanced greatly.
2008, 38(7): 116-119.
doi: 10.13204/j.gyjz200807029
Abstract:
The chimney of South Sichuan Gas Mine Purification Factory is a steel chimney lined with refractory bricks.In long-term use process,as exhaust surviving sulfur and other corrosive matters it has serious corrosion and aging.It can not meet the simple reproduction and expansion reproduction need.Which needs reinforcement measures immediately.According to the specific corrosive defects at this chimney,a reliability assessment is done.Through massive computer simulation and finite element computation of residual strength the chimney weak link is got and a comparative analysis of a few reinforcement plans is carried out.Finally reliable plan is obtained so that remarkable economic and social benefits are achieved.
The chimney of South Sichuan Gas Mine Purification Factory is a steel chimney lined with refractory bricks.In long-term use process,as exhaust surviving sulfur and other corrosive matters it has serious corrosion and aging.It can not meet the simple reproduction and expansion reproduction need.Which needs reinforcement measures immediately.According to the specific corrosive defects at this chimney,a reliability assessment is done.Through massive computer simulation and finite element computation of residual strength the chimney weak link is got and a comparative analysis of a few reinforcement plans is carried out.Finally reliable plan is obtained so that remarkable economic and social benefits are achieved.
2008, 38(7): 120-123.
doi: 10.13204/j.gyjz200807030
Abstract:
Nowadays,the trend of new development is the design of museum architectures by development and utilization of underground space.Based on the case study of 10 buries excavated in Yang Ling of hte Han Dynasty in Xi'an and the first domestic relic museum of underground which has been constructed,it is discussed the design means of underground spaces for museum architectures by starting in entrance shape,space organization,traffic line,interior deisgn and so on.
Nowadays,the trend of new development is the design of museum architectures by development and utilization of underground space.Based on the case study of 10 buries excavated in Yang Ling of hte Han Dynasty in Xi'an and the first domestic relic museum of underground which has been constructed,it is discussed the design means of underground spaces for museum architectures by starting in entrance shape,space organization,traffic line,interior deisgn and so on.
2008, 38(7): 124-127.
doi: 10.13204/j.gyjz200807031
Abstract:
It has been analysed that the distinguishing features of the creation factories in Shanghai from trade plan,interior design and architectural design.It is pointed out that creation factories are a way of industrial architecture reutilization.It is also proposed that the majority of creation factories in Shanghai are space utilization,whose developments are worth further probing into.
It has been analysed that the distinguishing features of the creation factories in Shanghai from trade plan,interior design and architectural design.It is pointed out that creation factories are a way of industrial architecture reutilization.It is also proposed that the majority of creation factories in Shanghai are space utilization,whose developments are worth further probing into.
2008, 38(7): 128-130.
doi: 10.13204/j.gyjz200807032
Abstract:
The rural occupy occupies 60 percent of total quantity of buildings in China.As compared with the urban building energy consumption,most of rural houses are higher energy consumption constructions.To meet the policy of energy saving and pollutant reduction as well as the establishment of socialist new rurality,it is attempted to design one kind of new rural house based on energy-saving concept and traditional houses.
The rural occupy occupies 60 percent of total quantity of buildings in China.As compared with the urban building energy consumption,most of rural houses are higher energy consumption constructions.To meet the policy of energy saving and pollutant reduction as well as the establishment of socialist new rurality,it is attempted to design one kind of new rural house based on energy-saving concept and traditional houses.
