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2008 Vol. 38, No. 8
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2008, 38(8): 1-5.
doi: 10.13204/j.gyjz200808001
Abstract:
Based on the Cam-clay model,the outstanding characteristics of the unified hardening model(UH model) are that the UH parameter is used to describe the stress dilatancy and the transformed stress tensors is used to exhibit the behaviour of clays in the three-dimensional stress space.The different models corresponding to the different soils are proposed modifying the hardening parameter appropriately.The UH model includes more than 10 models,which are the UH model for clays and sands,the UH model for overconsolidated clays,UH model for K_0 overconsolidated clays,the critical state model for sands dependent on stress and density,the model for soils with inherited anisotropy and so on.These models can describe the stress dilation/contraction,hardening/softening,overconsolidation,stress induced anisotropy,inherited anisotropy,creep,asymptotic state,rotational hardening,crushing under great stress and other characteristics of soils,respectively.
Based on the Cam-clay model,the outstanding characteristics of the unified hardening model(UH model) are that the UH parameter is used to describe the stress dilatancy and the transformed stress tensors is used to exhibit the behaviour of clays in the three-dimensional stress space.The different models corresponding to the different soils are proposed modifying the hardening parameter appropriately.The UH model includes more than 10 models,which are the UH model for clays and sands,the UH model for overconsolidated clays,UH model for K_0 overconsolidated clays,the critical state model for sands dependent on stress and density,the model for soils with inherited anisotropy and so on.These models can describe the stress dilation/contraction,hardening/softening,overconsolidation,stress induced anisotropy,inherited anisotropy,creep,asymptotic state,rotational hardening,crushing under great stress and other characteristics of soils,respectively.
2008, 38(8): 6-9.
doi: 10.13204/j.gyjz200808002
Abstract:
An inherent anisotropic unified hardening model for soils was presented using an anisotropic parameter .The inherent anisotropy of soils can be processed as isotropy transforming its stresses into the equivalent isotropic soil. Parameter can be obtained from the conventional triaxial compression tests and triaxial extension tests of the inherent anisotropic soils.The model is well demonstrated by comparison of the predicted stress-strain curve and test results of Toyoura sand under different stress conditions.
An inherent anisotropic unified hardening model for soils was presented using an anisotropic parameter .The inherent anisotropy of soils can be processed as isotropy transforming its stresses into the equivalent isotropic soil. Parameter can be obtained from the conventional triaxial compression tests and triaxial extension tests of the inherent anisotropic soils.The model is well demonstrated by comparison of the predicted stress-strain curve and test results of Toyoura sand under different stress conditions.
2008, 38(8): 10-13,20.
doi: 10.13204/j.gyjz200808003
Abstract:
A mixed strain hardening constitutive model,which can describe the induced anisotropy of soils,is proposed combining the rotational hardening mechanism with the unified hardening model.The drained stress path for clay and the undrained stress path for sand are predicted using the proposed model.It is indicated that the proposed model can describe both the stress-strain relationship of clay and the stress-strain relationship of the saturated sand under various cyclic loading conditions well.
A mixed strain hardening constitutive model,which can describe the induced anisotropy of soils,is proposed combining the rotational hardening mechanism with the unified hardening model.The drained stress path for clay and the undrained stress path for sand are predicted using the proposed model.It is indicated that the proposed model can describe both the stress-strain relationship of clay and the stress-strain relationship of the saturated sand under various cyclic loading conditions well.
2008, 38(8): 14-16,58.
doi: 10.13204/j.gyjz200808004
Abstract:
Based on the subloading yield surface and the Cam-clay model,the proposed unified hardening model is used to describe the characteristics for over-consolidated clay with structure,including strain hardening,strain softening and stress dilatancy.The constitutive model for over-consolidated clays with structure is proposed introducing the parameter related to the structure of clays and requires two additional parameters,which are the slope of the Hvorslev envelope and the structure parameter.The predicted results of structurally over-consolidated clays show that the proposed model can rationally describe the basic properties for structurally over-consolidated clays.
Based on the subloading yield surface and the Cam-clay model,the proposed unified hardening model is used to describe the characteristics for over-consolidated clay with structure,including strain hardening,strain softening and stress dilatancy.The constitutive model for over-consolidated clays with structure is proposed introducing the parameter related to the structure of clays and requires two additional parameters,which are the slope of the Hvorslev envelope and the structure parameter.The predicted results of structurally over-consolidated clays show that the proposed model can rationally describe the basic properties for structurally over-consolidated clays.
2008, 38(8): 17-20.
doi: 10.13204/j.gyjz200808005
Abstract:
Based on the particle crushing of granular material,which affects the mechanical characteristic of stress dilatancy,and the power function used to describe the characteristic stress ratio,it is developed that the yield surface and its expression of the characteristic state.It is also analyzed the change law of the yield surface according to the value of parameters.The yield surface of characteristic state will be the same as the modified Cam-clay model when the parameter equals to a special value.Finally,combined with proper isotropic compressed conditions and unified hardening parameter,the yield surface can be applied into the constitutive model for sand,which can predict the tests results well,and describe the mechanical characteristic of sand exhibiting particle crushing reasonably.
Based on the particle crushing of granular material,which affects the mechanical characteristic of stress dilatancy,and the power function used to describe the characteristic stress ratio,it is developed that the yield surface and its expression of the characteristic state.It is also analyzed the change law of the yield surface according to the value of parameters.The yield surface of characteristic state will be the same as the modified Cam-clay model when the parameter equals to a special value.Finally,combined with proper isotropic compressed conditions and unified hardening parameter,the yield surface can be applied into the constitutive model for sand,which can predict the tests results well,and describe the mechanical characteristic of sand exhibiting particle crushing reasonably.
2008, 38(8): 21-24.
doi: 10.13204/j.gyjz200808006
Abstract:
The unified hardening model for over-consolidated clays(for short as UH model) can simulate many characteristics of over-consolidated clays well,including stress-strain relationships,stress dilatancy,strain hardening and softening, and path dependency behavior.Through the triaxial drained tests for the nature state clays in Beijing Olympic Forest Park,the material parameters of the UH model are determined.The comparison between the model predictions and the test results indicate the UH model can describe the mechanical behavior of over-consolidated clays rationally.
The unified hardening model for over-consolidated clays(for short as UH model) can simulate many characteristics of over-consolidated clays well,including stress-strain relationships,stress dilatancy,strain hardening and softening, and path dependency behavior.Through the triaxial drained tests for the nature state clays in Beijing Olympic Forest Park,the material parameters of the UH model are determined.The comparison between the model predictions and the test results indicate the UH model can describe the mechanical behavior of over-consolidated clays rationally.
2008, 38(8): 25-27,113.
doi: 10.13204/j.gyjz200808007
Abstract:
The original unified hardening model(UH model) is established based on the linear relation of v-lnp under isotropic consolidation.As the linear relation of v-lnp has some theoretical shortcomings,a modified UH model is deduced based on the linear relation of lnv-lnp proposed by Hashiguchi et al,which is proved to be more reasonable for soils.The predicted results of the two models are compared.They are very similar.The disadvantages of the original model cause little error under common conditions only.
The original unified hardening model(UH model) is established based on the linear relation of v-lnp under isotropic consolidation.As the linear relation of v-lnp has some theoretical shortcomings,a modified UH model is deduced based on the linear relation of lnv-lnp proposed by Hashiguchi et al,which is proved to be more reasonable for soils.The predicted results of the two models are compared.They are very similar.The disadvantages of the original model cause little error under common conditions only.
2008, 38(8): 28-30.
doi: 10.13204/j.gyjz200808008
Abstract:
The development of economy accelerates the process of urbanization,and leads to the vanishing of urban culture and,at the same time,makes the desertification of urban culture become more severe day by day.In facing with the(citys) desertification,it is proposed an idea of city stage,i.e.through a new function which is transplanted in the disused old industrial factory buildings and meets the needs of mordern people,which can attract a great number of them to show their concern,and thus restoring the desert to the beach.
The development of economy accelerates the process of urbanization,and leads to the vanishing of urban culture and,at the same time,makes the desertification of urban culture become more severe day by day.In facing with the(citys) desertification,it is proposed an idea of city stage,i.e.through a new function which is transplanted in the disused old industrial factory buildings and meets the needs of mordern people,which can attract a great number of them to show their concern,and thus restoring the desert to the beach.
2008, 38(8): 31-34.
doi: 10.13204/j.gyjz200808009
Abstract:
Inspired by the successful renovation of old industrial buildings in abroad,the old industrial buildings in China are no longer be abandoned without any consideration.Taking the renovation of old industrial buildings in Shanghai Expo Garden for example,a large scale planning and designing movement is launched by the government to protect and renovate the old industrial buildings.At this beginning,it is analysed the situation and suggested that the old industrial buildings should be classified,and treaded differently according to their different nature of value.Only after the successful transformation,can the old industrial buildings be renewed.
Inspired by the successful renovation of old industrial buildings in abroad,the old industrial buildings in China are no longer be abandoned without any consideration.Taking the renovation of old industrial buildings in Shanghai Expo Garden for example,a large scale planning and designing movement is launched by the government to protect and renovate the old industrial buildings.At this beginning,it is analysed the situation and suggested that the old industrial buildings should be classified,and treaded differently according to their different nature of value.Only after the successful transformation,can the old industrial buildings be renewed.
2008, 38(8): 35-38,34.
doi: 10.13204/j.gyjz200808010
Abstract:
Developing solar buildings,it is an effective approach to realizing the strategic objective of energy saving and emission reduction in the architecture field of China.The instability of the energy supply in the solar energy utilization is one of the main obstacles to the popularization of solar buildings.The solution to this problem depends on not only the improvement of the equipment in the technology aspect,but also the conception of adaptability combined into the architecture by the architect,in order to utilize advantages and avoidi drawbacks in the process of solar energy utilization,thus achieving the design of scientific and appropriate solar buildings.
Developing solar buildings,it is an effective approach to realizing the strategic objective of energy saving and emission reduction in the architecture field of China.The instability of the energy supply in the solar energy utilization is one of the main obstacles to the popularization of solar buildings.The solution to this problem depends on not only the improvement of the equipment in the technology aspect,but also the conception of adaptability combined into the architecture by the architect,in order to utilize advantages and avoidi drawbacks in the process of solar energy utilization,thus achieving the design of scientific and appropriate solar buildings.
2008, 38(8): 39-41,45.
doi: 10.13204/j.gyjz200808011
Abstract:
Two wind load bearing schemes for the new building structure are firstly advanced.The idea of setting additive column in this new building structure is firstly proposed.Based on the two load-bearing schemes,the effect of the stiffness of additive column on the dynamic performances of the top mega and sub-structure subjected to pulsating wind loads is investigated.The dynamical responses of the holistic sub-structure with different stiffness of the additive column are analyzed.The research indicates that additive column can adjust the dynamic performance of this new building structure,and effectively improve its holistic vibration-resistance ability.
Two wind load bearing schemes for the new building structure are firstly advanced.The idea of setting additive column in this new building structure is firstly proposed.Based on the two load-bearing schemes,the effect of the stiffness of additive column on the dynamic performances of the top mega and sub-structure subjected to pulsating wind loads is investigated.The dynamical responses of the holistic sub-structure with different stiffness of the additive column are analyzed.The research indicates that additive column can adjust the dynamic performance of this new building structure,and effectively improve its holistic vibration-resistance ability.
2008, 38(8): 42-45.
doi: 10.13204/j.gyjz200808012
Abstract:
This paper analyses nonlinear behaviors and seismic performances of 4 unbonded post-tensioned precast concrete beams with ADINA finite element software.The gap opening/closing,stress distribution,specimen deformation,the hysteresis framework relationship are in good agreement with those of the tests.It is shown that the model is very effective for gaining detailed knowledge of the nonlinear behavior and seismic performance of unbonded post-tensioned precast concrete beams.
This paper analyses nonlinear behaviors and seismic performances of 4 unbonded post-tensioned precast concrete beams with ADINA finite element software.The gap opening/closing,stress distribution,specimen deformation,the hysteresis framework relationship are in good agreement with those of the tests.It is shown that the model is very effective for gaining detailed knowledge of the nonlinear behavior and seismic performance of unbonded post-tensioned precast concrete beams.
2008, 38(8): 46-49,82.
doi: 10.13204/j.gyjz200808013
Abstract:
Low-cyclic loading tests were made on two RC frame structures,each of which was made up of two L section and one T section columns.Several aspects,such as the test phenomena,failure characters,hysteretic curves and deformation performances,are described and analyzed.Analysis result shows that 2 story RC frame structure has good seismic performances.Besides,nonlinear analysis software MARC is used to simulate the framework curve and the sequence of plastic hinges,the results of the analysis have good coincidence with those of the tests.
Low-cyclic loading tests were made on two RC frame structures,each of which was made up of two L section and one T section columns.Several aspects,such as the test phenomena,failure characters,hysteretic curves and deformation performances,are described and analyzed.Analysis result shows that 2 story RC frame structure has good seismic performances.Besides,nonlinear analysis software MARC is used to simulate the framework curve and the sequence of plastic hinges,the results of the analysis have good coincidence with those of the tests.
2008, 38(8): 50-53,108.
doi: 10.13204/j.gyjz200808014
Abstract:
Through the three-point bending test on notched beams of steel fiber reinforced high-strength concrete(SFHSC) with the relative notch depth of 0.2,0.3,0.4 and 0.5,the effect of the steel fiber volume fraction upon fracture properties of high strength concrete was studied.The results show that under the four relative depth conditions the SFRC fracture toughness and fracture energy significantly increase as the steel fiber volume fraction increases.Based on the statistical analysis of test results,the formula were established for the relationship of the fracture toughness and fracture energy with the tensile strength of steel fiber reinforced high strength concrete respectively.
Through the three-point bending test on notched beams of steel fiber reinforced high-strength concrete(SFHSC) with the relative notch depth of 0.2,0.3,0.4 and 0.5,the effect of the steel fiber volume fraction upon fracture properties of high strength concrete was studied.The results show that under the four relative depth conditions the SFRC fracture toughness and fracture energy significantly increase as the steel fiber volume fraction increases.Based on the statistical analysis of test results,the formula were established for the relationship of the fracture toughness and fracture energy with the tensile strength of steel fiber reinforced high strength concrete respectively.
2008, 38(8): 54-58.
doi: 10.13204/j.gyjz200808015
Abstract:
Geometrically similar three-point bending beams with straight-through crack were prepared for concrete of two compositions.Through MTS 815 material test machine,mechanical parameters of two concretes were tested,and load vs.LPD(load point displacement) curves and load vs.CMOD(crack mouth opening displacement) curves of entire process were recorded for three-point bending specimens.There is a distinct size effect for fracture toughness K_(IC) calculated with maximum load and initial crack length.To cope with this problem,using the size-effect method recommended by RILEM(Runion Internationale des Laboratoires et Experts des Matriaux),the material true fracture toughness and effective length of the fracture process zone were obtained.The size effect law of fracture toughness for the two concrete materials is thus determined respectively.Fracture toughness and fracture process zone length can be seen from this formula for large-sized specimens of the same material.It can also be used to predict the fracture toughness for geometrically similar specimens to be tested in laboratory.
Geometrically similar three-point bending beams with straight-through crack were prepared for concrete of two compositions.Through MTS 815 material test machine,mechanical parameters of two concretes were tested,and load vs.LPD(load point displacement) curves and load vs.CMOD(crack mouth opening displacement) curves of entire process were recorded for three-point bending specimens.There is a distinct size effect for fracture toughness K_(IC) calculated with maximum load and initial crack length.To cope with this problem,using the size-effect method recommended by RILEM(Runion Internationale des Laboratoires et Experts des Matriaux),the material true fracture toughness and effective length of the fracture process zone were obtained.The size effect law of fracture toughness for the two concrete materials is thus determined respectively.Fracture toughness and fracture process zone length can be seen from this formula for large-sized specimens of the same material.It can also be used to predict the fracture toughness for geometrically similar specimens to be tested in laboratory.
2008, 38(8): 59-62,98.
doi: 10.13204/j.gyjz200808016
Abstract:
The influence of water-cement ratio on performance of grouts is studied,the mechanism of admixture to improve performance of grouts are analysed and the grouts'resistance to chloride ion erosion is studied by total chloride ion content,electric charge and chloride ion diffusion coefficient.The results show that high performance grouts with zero bleeding,no shrinking,high flowability,high ability to resist chloride ion penetration and low water-cement ratio(0.27～0.30) are developed;the direct ratio relationship between electric charge and chloride ion diffusion coefficient is induced according to Nernst-Einstein equation.Electric charge can be reduced and grouts' ability to resist chloride ion penetration can be improved largely by reducing water-cement ratio.
The influence of water-cement ratio on performance of grouts is studied,the mechanism of admixture to improve performance of grouts are analysed and the grouts'resistance to chloride ion erosion is studied by total chloride ion content,electric charge and chloride ion diffusion coefficient.The results show that high performance grouts with zero bleeding,no shrinking,high flowability,high ability to resist chloride ion penetration and low water-cement ratio(0.27～0.30) are developed;the direct ratio relationship between electric charge and chloride ion diffusion coefficient is induced according to Nernst-Einstein equation.Electric charge can be reduced and grouts' ability to resist chloride ion penetration can be improved largely by reducing water-cement ratio.
2008, 38(8): 63-66,85.
doi: 10.13204/j.gyjz200808017
Abstract:
The relationships between the critical chloride concentration in marine concrete,the chloride diffusion coefficient of concrete and the water cement ratio,temperature of environment are established.The chloride concentration near surface of the steel bars in concrete eroded by the sea water in 50 years is analyzed.Based on the analysis of the relation of chloride concentration near surface of the steel bars to service time,the reliability of the steel bars depassivation is investigated by Monte Carlo method.The influence of stochastic variables,such as concrete cover to reinforcement,water-cement ratio,temperature of environment,etc,on the reliability of the steel bars depassivation in marine concrete is discussed.
The relationships between the critical chloride concentration in marine concrete,the chloride diffusion coefficient of concrete and the water cement ratio,temperature of environment are established.The chloride concentration near surface of the steel bars in concrete eroded by the sea water in 50 years is analyzed.Based on the analysis of the relation of chloride concentration near surface of the steel bars to service time,the reliability of the steel bars depassivation is investigated by Monte Carlo method.The influence of stochastic variables,such as concrete cover to reinforcement,water-cement ratio,temperature of environment,etc,on the reliability of the steel bars depassivation in marine concrete is discussed.
2008, 38(8): 67-72.
doi: 10.13204/j.gyjz200808018
Abstract:
Nine angle-steel concrete columns(ASCC) under low cyclic loading are tested,whose axial compression ratio n_0 and stirrup ratio of steel plate stirrup _(sv) are 0.33～0.42 and 1.18%～2.09% respectively.The test results show that the large eccentric failure occurs in all specimens.The hysteretic curves for 9 specimens are acquired,and through analyzing these curves,the corresponding skeleton curves are obtained.Based on test research,the flexural mechanical behavior of ASCC is discussed.The calculation formulas of the flexural bearing capacity of ASCC are presented on the basis of plane-section assumption.The flexural bearing capacity calculated by the formulas agrees well with the test results
Nine angle-steel concrete columns(ASCC) under low cyclic loading are tested,whose axial compression ratio n_0 and stirrup ratio of steel plate stirrup _(sv) are 0.33～0.42 and 1.18%～2.09% respectively.The test results show that the large eccentric failure occurs in all specimens.The hysteretic curves for 9 specimens are acquired,and through analyzing these curves,the corresponding skeleton curves are obtained.Based on test research,the flexural mechanical behavior of ASCC is discussed.The calculation formulas of the flexural bearing capacity of ASCC are presented on the basis of plane-section assumption.The flexural bearing capacity calculated by the formulas agrees well with the test results
2008, 38(8): 73-77.
doi: 10.13204/j.gyjz200808019
Abstract:
The experimental results of 62 specimens with 550 MPa high strength cold-formed thin-wall steel under axial compression are analyzed by direct strength method(DSM).The bearing capacities of high strength cold-formed thin-walled steel columns under axial compression are calculated by reduced yield strength 0.85f_y and revised slenderness ratio _c=0.85f_y/235 for the stability coefficient from the stability coefficient table of Q235 in Technical Code for Cold-Formed Thin Walled Section Steel Stucture(GB 50018-2002).The calculated results by the suggested method are closed well to the test results.
The experimental results of 62 specimens with 550 MPa high strength cold-formed thin-wall steel under axial compression are analyzed by direct strength method(DSM).The bearing capacities of high strength cold-formed thin-walled steel columns under axial compression are calculated by reduced yield strength 0.85f_y and revised slenderness ratio _c=0.85f_y/235 for the stability coefficient from the stability coefficient table of Q235 in Technical Code for Cold-Formed Thin Walled Section Steel Stucture(GB 50018-2002).The calculated results by the suggested method are closed well to the test results.
2008, 38(8): 78-82.
doi: 10.13204/j.gyjz200808020
Abstract:
The experimental study on the 9 short CFST columns is conducted.On the basis of which,firstly,the failure phenomenon and mechanism analysis are conducted;then,the influence of the concrete strength,slenderness ratio and eccentricity ratio on the mechanical behavior of this sort of member is analyzed,which indicates that eccentricity ratio is the main influence parameter,the slenderness ratio in the range of short column and the concrete strength in the large eccentricity pressing have little effect on the behavior of this sort of member.And the rational suggestion is given on the application of the member in actual projects.
The experimental study on the 9 short CFST columns is conducted.On the basis of which,firstly,the failure phenomenon and mechanism analysis are conducted;then,the influence of the concrete strength,slenderness ratio and eccentricity ratio on the mechanical behavior of this sort of member is analyzed,which indicates that eccentricity ratio is the main influence parameter,the slenderness ratio in the range of short column and the concrete strength in the large eccentricity pressing have little effect on the behavior of this sort of member.And the rational suggestion is given on the application of the member in actual projects.
2008, 38(8): 83-85.
doi: 10.13204/j.gyjz200808021
Abstract:
Through an experiment on profiled steel sheet-light-weight aggregate concrete floor shabs,it is researched that the bearing and deforming capability,which are compared with the ordinary concrete composite slabs.It is verified the applicability of the design formula of bearing capacity in the Specifications for Structural Design and Construction of Steel-Concrete Floor Slab(YB 923892) and the Technical Specification for Steel Structure of Tall Buildings,(JGJ 99-98),which provides a basis for the application of composite slabs with light-weight aggregate concrete in projects
Through an experiment on profiled steel sheet-light-weight aggregate concrete floor shabs,it is researched that the bearing and deforming capability,which are compared with the ordinary concrete composite slabs.It is verified the applicability of the design formula of bearing capacity in the Specifications for Structural Design and Construction of Steel-Concrete Floor Slab(YB 923892) and the Technical Specification for Steel Structure of Tall Buildings,(JGJ 99-98),which provides a basis for the application of composite slabs with light-weight aggregate concrete in projects
2008, 38(8): 86-88.
doi: 10.13204/j.gyjz200808022
Abstract:
The optimal design of single-span portal frame is a design with geometric and physical restrictions.Using penalty function well solves the problems resulting from optimal design of the single-span tapered portal frame,and satisfactory results are got.
The optimal design of single-span portal frame is a design with geometric and physical restrictions.Using penalty function well solves the problems resulting from optimal design of the single-span tapered portal frame,and satisfactory results are got.
2008, 38(8): 89-91.
doi: 10.13204/j.gyjz200808023
Abstract:
According to the experimental data on 343 reinforced concrete beams without web reinforcement under concentrated load,formulas to calculate the mean shear strength of reinforced concrete beams without web reinforcement respectively with f_c,f_t and f_c had been established.The degree of reliability of the current code in calculating the shear strength of reinforced concrete beams without web reinforcement had also been discussed.Then a formula expressed by f_c to calculate the shear strength of reinforced concrete beams without web reinforcement had been given.
According to the experimental data on 343 reinforced concrete beams without web reinforcement under concentrated load,formulas to calculate the mean shear strength of reinforced concrete beams without web reinforcement respectively with f_c,f_t and f_c had been established.The degree of reliability of the current code in calculating the shear strength of reinforced concrete beams without web reinforcement had also been discussed.Then a formula expressed by f_c to calculate the shear strength of reinforced concrete beams without web reinforcement had been given.
2008, 38(8): 92-95.
doi: 10.13204/j.gyjz200808024
Abstract:
The Science Chamber in Tsinghua University is one of the most important architectures in recent China.It is made a introduction to the project's historical background,feasibility analysis,investigation,detection and some necessary researches respectively.Then,the strengthening measures and technologies are elaborated for its protection.Additionally,some key procedures during the whole process are further discussed in detail.
The Science Chamber in Tsinghua University is one of the most important architectures in recent China.It is made a introduction to the project's historical background,feasibility analysis,investigation,detection and some necessary researches respectively.Then,the strengthening measures and technologies are elaborated for its protection.Additionally,some key procedures during the whole process are further discussed in detail.
2008, 38(8): 96-98.
doi: 10.13204/j.gyjz200808025
Abstract:
A new composite material named Fiber Reinforced Polymer is used in the strengthening field of civil engineering widely.This new strengthened technology using prestress(called prestressed reinforcement) can availably develop the strong capacity of FRP.In order to know the mechanical characteristics of RC beam in bending capacity,experimental study and theoretical analysis are combined in the process of research.Twelve concrete beams reinforced by CFRP bar,BFRP bar and strand were made.The reinforced effects including cracking load,yielded load,ultimate load,development of crack,improvement on rigidity and destructive mode are compared and researched.
A new composite material named Fiber Reinforced Polymer is used in the strengthening field of civil engineering widely.This new strengthened technology using prestress(called prestressed reinforcement) can availably develop the strong capacity of FRP.In order to know the mechanical characteristics of RC beam in bending capacity,experimental study and theoretical analysis are combined in the process of research.Twelve concrete beams reinforced by CFRP bar,BFRP bar and strand were made.The reinforced effects including cracking load,yielded load,ultimate load,development of crack,improvement on rigidity and destructive mode are compared and researched.
2008, 38(8): 99-101,105.
doi: 10.13204/j.gyjz200808026
Abstract:
The building of car-dumping machine is a larger-span steel bent frame structure,where bridge crane is erected.Before technical reform,a reliability appraisal of the building's superstructure is done and a conclusion is also proposed.Finally,rational suggestions on design of roof tie bars are proposed after decreasing loads on column base and roof.
The building of car-dumping machine is a larger-span steel bent frame structure,where bridge crane is erected.Before technical reform,a reliability appraisal of the building's superstructure is done and a conclusion is also proposed.Finally,rational suggestions on design of roof tie bars are proposed after decreasing loads on column base and roof.
2008, 38(8): 102-105.
doi: 10.13204/j.gyjz200808027
Abstract:
Treatment schemes are put forward to solve the problems which exist in prestressed concrete crane girders according to real work condition.Through comparing and selecting the initial treatment schemes,sticking to CFRP sheets is chosen to strengthen crane girders.It is introduced that the design points and schemes to strengthen fish-bellied T section prestressed concrete crane girders using CFRP sheets, including the calculating methods of bending and shear bearing capacity as well as strengthening construction program.The examination shows that the technical indices of the crane girder strengthening meet the demands on design. The research results can be a reference in theory and method for the similar engineering.
Treatment schemes are put forward to solve the problems which exist in prestressed concrete crane girders according to real work condition.Through comparing and selecting the initial treatment schemes,sticking to CFRP sheets is chosen to strengthen crane girders.It is introduced that the design points and schemes to strengthen fish-bellied T section prestressed concrete crane girders using CFRP sheets, including the calculating methods of bending and shear bearing capacity as well as strengthening construction program.The examination shows that the technical indices of the crane girder strengthening meet the demands on design. The research results can be a reference in theory and method for the similar engineering.
2008, 38(8): 106-108.
doi: 10.13204/j.gyjz200808028
Abstract:
Based on analyzing the reasons of temperature cracks on blockwork,it is proposed that preventative measures to control temperature cracks in design,and methods of treating these cracks structure.
Based on analyzing the reasons of temperature cracks on blockwork,it is proposed that preventative measures to control temperature cracks in design,and methods of treating these cracks structure.
2008, 38(8): 109-113.
doi: 10.13204/j.gyjz200808029
Abstract:
By the no-joint design of a 103 m long sickroom building,it is analyzed the tensile stress caused by concrete shrinkage and temperature decreasing,also put forward a series of techniques to control the cracks.Post-poured strip was used to enhance the prestressing effect of steel bars.It is verified the distribution regularity of temperature stress and shrinkage stress and effectiveness of the above techniques by stress detecting during and after construction.
By the no-joint design of a 103 m long sickroom building,it is analyzed the tensile stress caused by concrete shrinkage and temperature decreasing,also put forward a series of techniques to control the cracks.Post-poured strip was used to enhance the prestressing effect of steel bars.It is verified the distribution regularity of temperature stress and shrinkage stress and effectiveness of the above techniques by stress detecting during and after construction.
2008, 38(8): 114-116.
doi: 10.13204/j.gyjz200808030
Abstract:
Based on analysis of Bottas industrial architecture works and speech,it is narrated the uses of Bottas theories of geometric prototype,remolding sites and returning to origin in the design of industrial architecture space,which strive to arouse building circle's of much attention to the study on design concept of industrial architecture.
Based on analysis of Bottas industrial architecture works and speech,it is narrated the uses of Bottas theories of geometric prototype,remolding sites and returning to origin in the design of industrial architecture space,which strive to arouse building circle's of much attention to the study on design concept of industrial architecture.
