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2007 Vol. 37, No. 5
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2007, 37(5): 1-4.
doi: 10.13204/j.gyjz200705001
Abstract:
Research on concrete constitutive model actually studies constitutive relation of concrete. Cumulative deformation of material can cause interior damage of structure under exterior load and the entire structure may collapse due to damage of concrete. According to energy dissipation damage theory by Najar, a new model of segments curves damage of concrete compression is investigated and equations are put forward for damage variables and evolvement with various degrees of concrete. In order to testify the validity of the model, the calculated results are compared with those of the existing constitutive model, and the result shows that the proposed model is agreed with the existing model, which may provide a new method for simulation analysis of damages to concrete structures.
Research on concrete constitutive model actually studies constitutive relation of concrete. Cumulative deformation of material can cause interior damage of structure under exterior load and the entire structure may collapse due to damage of concrete. According to energy dissipation damage theory by Najar, a new model of segments curves damage of concrete compression is investigated and equations are put forward for damage variables and evolvement with various degrees of concrete. In order to testify the validity of the model, the calculated results are compared with those of the existing constitutive model, and the result shows that the proposed model is agreed with the existing model, which may provide a new method for simulation analysis of damages to concrete structures.
2007, 37(5): 5-9.
doi: 10.13204/j.gyjz200705002
Abstract:
A section damage model is given based on damage constitutive relation of compression concrete and damage parameters is studied for L-shaped cross-section under biaxial bending with orthographic design method in order to select sensitivity factors. The research result indicates that the flange-thick ratio is the most important factor for the cross-section bearing capacity, the next is steel ratio and loading angle, which is a very important factor due to its asymmetry. Study also found out that steel ratio can reduce section damage, next is concrete strength, last one is loading angle which can aggravate section damage.
A section damage model is given based on damage constitutive relation of compression concrete and damage parameters is studied for L-shaped cross-section under biaxial bending with orthographic design method in order to select sensitivity factors. The research result indicates that the flange-thick ratio is the most important factor for the cross-section bearing capacity, the next is steel ratio and loading angle, which is a very important factor due to its asymmetry. Study also found out that steel ratio can reduce section damage, next is concrete strength, last one is loading angle which can aggravate section damage.
2007, 37(5): 10-13.
doi: 10.13204/j.gyjz200705003
Abstract:
A structural damage identification technique based on wavelet transform of spatial structural response measurements is discussed. The two different boundary conditions considered are simply supported and fixed end support, and the different damage forms (crack characteristics) are investigated by numerical experiments. The results of the simulation show that boundary conditions have some effect on bridge damage detection, but the damage forms have no effect on it. All in all, if a suitable wavelet is selected, the method is capable to extract damage information from the response signal in a simple and reliable way.
A structural damage identification technique based on wavelet transform of spatial structural response measurements is discussed. The two different boundary conditions considered are simply supported and fixed end support, and the different damage forms (crack characteristics) are investigated by numerical experiments. The results of the simulation show that boundary conditions have some effect on bridge damage detection, but the damage forms have no effect on it. All in all, if a suitable wavelet is selected, the method is capable to extract damage information from the response signal in a simple and reliable way.
2007, 37(5): 14-19.
doi: 10.13204/j.gyjz200705004
Abstract:
RC structures may damage during their lifetime with the effect of loads, earthquake action, and other factors. And the damage is harmful to the safety of the structure. To guarantee the safety of a structure, it is very important to detect and identify the structural damage at the earliest stage during its lifetime. Based on the characteristic of mult-i resolution of wavelet transforms, a damage identification method, namely delamination wavele-t transform search method, is proposed, which can be used to have an online detection of the occurrence and the location of damage inside RC structure. Numerical simulation for a RC frame verifies that the method is feasible theoretically. Then a model of three-story RC frame is made and tested on a shaking table and the damage of the model structure is identified using the proposed method. It is confirmed that the analytic results of wavelet transform method agree with the results observed in the test.
RC structures may damage during their lifetime with the effect of loads, earthquake action, and other factors. And the damage is harmful to the safety of the structure. To guarantee the safety of a structure, it is very important to detect and identify the structural damage at the earliest stage during its lifetime. Based on the characteristic of mult-i resolution of wavelet transforms, a damage identification method, namely delamination wavele-t transform search method, is proposed, which can be used to have an online detection of the occurrence and the location of damage inside RC structure. Numerical simulation for a RC frame verifies that the method is feasible theoretically. Then a model of three-story RC frame is made and tested on a shaking table and the damage of the model structure is identified using the proposed method. It is confirmed that the analytic results of wavelet transform method agree with the results observed in the test.
2007, 37(5): 20-22.
doi: 10.13204/j.gyjz200705005
Abstract:
Engineering structure parameter identification method applied with time series ARMA modeling under ambient ex citation was researched. Then combined with traditional model experiment theory two check model experiments were done on a multistorey frame, and the results of the two experiments were highly consistent. The analysis indicated time series ARMA model can ex actly and validly identify model parameters of engineering structure under circumstances which traditional model experiment may be difficult to process, and with these merits it had value in engineering application for providing model parameters for on-line monitor and active control of engineering structure.
Engineering structure parameter identification method applied with time series ARMA modeling under ambient ex citation was researched. Then combined with traditional model experiment theory two check model experiments were done on a multistorey frame, and the results of the two experiments were highly consistent. The analysis indicated time series ARMA model can ex actly and validly identify model parameters of engineering structure under circumstances which traditional model experiment may be difficult to process, and with these merits it had value in engineering application for providing model parameters for on-line monitor and active control of engineering structure.
2007, 37(5): 23-25.
doi: 10.13204/j.gyjz200705006
Abstract:
The concept of assessment reference period is put forward. The relation among exceeding probability, recurrence period and annual mean incidence of intensity is deduced. The recurrence periods of minor, moderate and major earthquake in different re service periods are calculated based on equal exceeding principle. The method of determining basic intensity, frequent intensity and rare intensity, together with their relation is presented using the reference of the latest research findings of earthquake hazard analysis. And the maximum of seismic influence coefficient is g iven for practical use. Finally, a Typical ex ample is given for explanation.
The concept of assessment reference period is put forward. The relation among exceeding probability, recurrence period and annual mean incidence of intensity is deduced. The recurrence periods of minor, moderate and major earthquake in different re service periods are calculated based on equal exceeding principle. The method of determining basic intensity, frequent intensity and rare intensity, together with their relation is presented using the reference of the latest research findings of earthquake hazard analysis. And the maximum of seismic influence coefficient is g iven for practical use. Finally, a Typical ex ample is given for explanation.
2007, 37(5): 26-29.
doi: 10.13204/j.gyjz200705007
Abstract:
Based on the characteristic of damage identification for engineering structure, a method of damage identification is put forward. First, with test modal reference the flexibility matrix of structure is set. And by the characterristic of the change in flexibility matrix before and after the damage to the structure, the position of damage in structure is found. Then based on that position, the damage state in structure is idertificated by method of fuzzy pattern recognition. At last, by giving a calculation example of a truss structure, it proves that the method has better stability, better anti-noise, and is much more accurate in identification, so it is very practical in engineerings.
Based on the characteristic of damage identification for engineering structure, a method of damage identification is put forward. First, with test modal reference the flexibility matrix of structure is set. And by the characterristic of the change in flexibility matrix before and after the damage to the structure, the position of damage in structure is found. Then based on that position, the damage state in structure is idertificated by method of fuzzy pattern recognition. At last, by giving a calculation example of a truss structure, it proves that the method has better stability, better anti-noise, and is much more accurate in identification, so it is very practical in engineerings.
2007, 37(5): 30-33.
doi: 10.13204/j.gyjz200705008
Abstract:
A practical method for analyzing the reliability of existing structural systems is put forward. The minimum value of the storey reliability is suggested to be the structural reliability. The storey reliability is constifuled of the one of each member by weight function, which is combined by the ratio of load vs. resistance and other modified coefficent. The aseismic benefit function of existing reinforced concrete frame structure is established based on the shear-resisting capacity of columns according to the previous earthquake damage. T he influence factors of carbonization of concrete and structural load are analyzed. A practical case of reinforced concrete structure is given herein, the aseismic reliability of the orig inal structure and those of the structure strengthened by three different methods are calculated respectively.
A practical method for analyzing the reliability of existing structural systems is put forward. The minimum value of the storey reliability is suggested to be the structural reliability. The storey reliability is constifuled of the one of each member by weight function, which is combined by the ratio of load vs. resistance and other modified coefficent. The aseismic benefit function of existing reinforced concrete frame structure is established based on the shear-resisting capacity of columns according to the previous earthquake damage. T he influence factors of carbonization of concrete and structural load are analyzed. A practical case of reinforced concrete structure is given herein, the aseismic reliability of the orig inal structure and those of the structure strengthened by three different methods are calculated respectively.
2007, 37(5): 34-36.
doi: 10.13204/j.gyjz200705009
Abstract:
It is discussed in the design of the Yuanding residential community project how to form the character of the professors. apartments. Building typology classification is introduced in the article to search for the prototypes and their alternations according to the city, environment and architectural detail, in addition, the occupants. physical and psychological requirements are also analyzed in the design. It is a valuable reference to other architects.
It is discussed in the design of the Yuanding residential community project how to form the character of the professors. apartments. Building typology classification is introduced in the article to search for the prototypes and their alternations according to the city, environment and architectural detail, in addition, the occupants. physical and psychological requirements are also analyzed in the design. It is a valuable reference to other architects.
2007, 37(5): 37-40.
doi: 10.13204/j.gyjz200705010
Abstract:
The development of energy-saving building brings the updating of construction structure. The energy consumption of construction in the use process need be studied, the design of a roofing is a very important part of energy conservation. Aiming at the details of construction for structure energy conservation of roofing, researches were done and some new design comcepts are presented.
The development of energy-saving building brings the updating of construction structure. The energy consumption of construction in the use process need be studied, the design of a roofing is a very important part of energy conservation. Aiming at the details of construction for structure energy conservation of roofing, researches were done and some new design comcepts are presented.
2007, 37(5): 41-44.
doi: 10.13204/j.gyjz200705011
Abstract:
The Heilongjiang central towns of forest zone belong to towns of resource renewal, it is one special group in Chinese small towns, they developed with resource, but with resource exhausted and policy adjusted, they fall into difficult condition day by day. It's an urgent problem how to study land layout of central towns with sustainable principle. From plenty of town's investigation data, each forestry department related to forestry is selected. A statistical method is used. The statistical analysis of 69 forestry departments shows that they have the similar natural condition. Central town exists normally with independent form, small scale with broad distribution. Industrial layout scatters mainly with state-owned large-scale forest industry, intensive utility of land and space fairly scatter. Based on investigation for the central town, land use four suggestions on countermeasures are proposed.
The Heilongjiang central towns of forest zone belong to towns of resource renewal, it is one special group in Chinese small towns, they developed with resource, but with resource exhausted and policy adjusted, they fall into difficult condition day by day. It's an urgent problem how to study land layout of central towns with sustainable principle. From plenty of town's investigation data, each forestry department related to forestry is selected. A statistical method is used. The statistical analysis of 69 forestry departments shows that they have the similar natural condition. Central town exists normally with independent form, small scale with broad distribution. Industrial layout scatters mainly with state-owned large-scale forest industry, intensive utility of land and space fairly scatter. Based on investigation for the central town, land use four suggestions on countermeasures are proposed.
2007, 37(5): 45-47.
doi: 10.13204/j.gyjz200705012
Abstract:
It is illustrated that pass ive buildings about the energy-saving by three aspects: the glacis strategy of plane layout, the effect of different exterior areas with different forms, and the ways of how to deal with the structure of outer enclosure, in which water-loop heat pump air-conditioning system is taken as the key point. From the illustration above, it is also expounded the passive buildings' advantage and feas ibility, and affirmed their contribution to human sustainable development.
It is illustrated that pass ive buildings about the energy-saving by three aspects: the glacis strategy of plane layout, the effect of different exterior areas with different forms, and the ways of how to deal with the structure of outer enclosure, in which water-loop heat pump air-conditioning system is taken as the key point. From the illustration above, it is also expounded the passive buildings' advantage and feas ibility, and affirmed their contribution to human sustainable development.
2007, 37(5): 48-52.
doi: 10.13204/j.gyjz200705013
Abstract:
Following the technique proposed by Muki Sternberg, the second kind Fredholm. s integral equation is deduced to solve the interaction factors between long-short piles. Using the principle of superposition a foundation with longshort piles is calculated. Compared with the results obtained using other methods by routine theory of elasticity, it shows that the strengthening effects of intervening piles on pile group settlement and individual pile load sharing are obvious. Finally, an extensive parametric analysis is made to study the foundation with long-short piles. The numerical analysis shows that the present method can be readily used to analyse large pile groups.
Following the technique proposed by Muki Sternberg, the second kind Fredholm. s integral equation is deduced to solve the interaction factors between long-short piles. Using the principle of superposition a foundation with longshort piles is calculated. Compared with the results obtained using other methods by routine theory of elasticity, it shows that the strengthening effects of intervening piles on pile group settlement and individual pile load sharing are obvious. Finally, an extensive parametric analysis is made to study the foundation with long-short piles. The numerical analysis shows that the present method can be readily used to analyse large pile groups.
2007, 37(5): 53-56.
doi: 10.13204/j.gyjz200705014
Abstract:
Recently,long-short-pile composite foundation as a new type of composite foundation is developed.But theoretical study and experience still need to be discussed deeply.A field experiment on long-short-pile composite foundation with prestressed high strength concrete(PHC) pile was carried out.The magnitude of the stress between pile and soil,pile-soil stress ratio,pile-soil load-sharing ratio and settlement and their variation with the load under rigid foundation or flexible foundation were measured and comparably analyzed.The research production can provide valuable reference for the theoretical study and optimization design of long-short-pile composite foundation.
Recently,long-short-pile composite foundation as a new type of composite foundation is developed.But theoretical study and experience still need to be discussed deeply.A field experiment on long-short-pile composite foundation with prestressed high strength concrete(PHC) pile was carried out.The magnitude of the stress between pile and soil,pile-soil stress ratio,pile-soil load-sharing ratio and settlement and their variation with the load under rigid foundation or flexible foundation were measured and comparably analyzed.The research production can provide valuable reference for the theoretical study and optimization design of long-short-pile composite foundation.
2007, 37(5): 57-60.
doi: 10.13204/j.gyjz200705015
Abstract:
Based on the theory of Particle Flow Code in 2 Dimensions(PFC~(2D)),a pile with expanded diameter that is compressed is studied,and is compared with the results of actual pile tests.Using PFC~(2D),the time step-displacement curve,the change of particle position and the displacement of particles are studied.Through the comparison of micro-mechanical properties of pile and soil during loading,the failure behavior of pile whose ultimate load is reached is also obtained.The relations between load and displacement are simulated and compared with the results of actual pile tests.
Based on the theory of Particle Flow Code in 2 Dimensions(PFC~(2D)),a pile with expanded diameter that is compressed is studied,and is compared with the results of actual pile tests.Using PFC~(2D),the time step-displacement curve,the change of particle position and the displacement of particles are studied.Through the comparison of micro-mechanical properties of pile and soil during loading,the failure behavior of pile whose ultimate load is reached is also obtained.The relations between load and displacement are simulated and compared with the results of actual pile tests.
2007, 37(5): 61-64.
doi: 10.13204/j.gyjz200705016
Abstract:
It is reported a series of tests on three long H-piles installed into sandy deposits.Two of the piles was installed by a 900t jacking machine in accordance with a pre-creep termination criterion.The other pile was installed by hydraulic hammer in accordance with the requirement of final sets.Vibrating wire strain gauges were installed along the piles to investigate the load-transfer characteristics during load tests.The test results show that the jacked piles behave as friction piles while the driven pile is much more end-bearing.The driven pile was founded on deeper and stiffer soil stratum than the jacked piles.However,its ultimate bearing capacity is not higher than the jacked pile that ever experienced jacking load as large as 2.5 times of the working load.The bearing capacities of the jacked piles are highly related to the level of jacking load applied during installation.The pre-creep termination criterion takes great effect on reducing the creep settlements of the jacked piles during load tests,hence increasing their bearing capacities.
It is reported a series of tests on three long H-piles installed into sandy deposits.Two of the piles was installed by a 900t jacking machine in accordance with a pre-creep termination criterion.The other pile was installed by hydraulic hammer in accordance with the requirement of final sets.Vibrating wire strain gauges were installed along the piles to investigate the load-transfer characteristics during load tests.The test results show that the jacked piles behave as friction piles while the driven pile is much more end-bearing.The driven pile was founded on deeper and stiffer soil stratum than the jacked piles.However,its ultimate bearing capacity is not higher than the jacked pile that ever experienced jacking load as large as 2.5 times of the working load.The bearing capacities of the jacked piles are highly related to the level of jacking load applied during installation.The pre-creep termination criterion takes great effect on reducing the creep settlements of the jacked piles during load tests,hence increasing their bearing capacities.
2007, 37(5): 65-68.
doi: 10.13204/j.gyjz200705017
Abstract:
According to the test method recommended by RILEM,three-point bending tests on notched beams of steel-fiber reinforced high-performance concrete(SFHPC) were carried out.The experimental results show that both steel fiber type and steel fiber content play important roles in the flexural toughness and fracture energy of high-performance concrete(HPC).The energy absorption capacity and fracture energy of SFHPC increase obviously with the increase of steel fiber content.Compared to the marked steel fiber with lower strength,the hooked steel fiber with higher strength has better effects on the flexural toughness and fracture energy of HPC.The mechanical and failure characteristics of SFHPC beams in bending test can be described well by using fracture energy and flexural toughness indices together.
According to the test method recommended by RILEM,three-point bending tests on notched beams of steel-fiber reinforced high-performance concrete(SFHPC) were carried out.The experimental results show that both steel fiber type and steel fiber content play important roles in the flexural toughness and fracture energy of high-performance concrete(HPC).The energy absorption capacity and fracture energy of SFHPC increase obviously with the increase of steel fiber content.Compared to the marked steel fiber with lower strength,the hooked steel fiber with higher strength has better effects on the flexural toughness and fracture energy of HPC.The mechanical and failure characteristics of SFHPC beams in bending test can be described well by using fracture energy and flexural toughness indices together.
2007, 37(5): 69-72.
doi: 10.13204/j.gyjz200705018
Abstract:
Based on the salt solution pickling test,alkali solution pickling test and accelerated aging test,the mechanical properties of CFRP under corrosive environment were studied.The stress-strain curve of CFRP was analyzed and the significance of mechanical properties of CFRP was tested.The test results indicate that CFRP shows good corrosion resistance.The tensile strength of CFRP had no significant change in the corrosive environments.The extensibility of CFRP has significant changes in the corrosive environments.The elastic modulus of CFRP has significant changes in the salt solution pickling condition and alkali solution pickling condition,there is no significant changes in the accelerated aging condition.
Based on the salt solution pickling test,alkali solution pickling test and accelerated aging test,the mechanical properties of CFRP under corrosive environment were studied.The stress-strain curve of CFRP was analyzed and the significance of mechanical properties of CFRP was tested.The test results indicate that CFRP shows good corrosion resistance.The tensile strength of CFRP had no significant change in the corrosive environments.The extensibility of CFRP has significant changes in the corrosive environments.The elastic modulus of CFRP has significant changes in the salt solution pickling condition and alkali solution pickling condition,there is no significant changes in the accelerated aging condition.
2007, 37(5): 73-76.
doi: 10.13204/j.gyjz200705019
Abstract:
The features and difficulties during the whole process of the steel structures of National Stadium project are introduced.The emphases are the fabrication technologies of flexural-torsional members,huge pedestal footings and trusses,the key erection technologies of the main structure and substructures.
The features and difficulties during the whole process of the steel structures of National Stadium project are introduced.The emphases are the fabrication technologies of flexural-torsional members,huge pedestal footings and trusses,the key erection technologies of the main structure and substructures.
2007, 37(5): 77-81.
doi: 10.13204/j.gyjz200705020
Abstract:
It is studied the main affection on bond performance between high-strength reinforcing bar and high-strength concrete by pull-out experiment of 48 specimens.It is analysed the causes of devastating phenomenon and compared to the classical load-slip curves of different base based on experiment.The test results revealed that its bond strength increases by decreasing anchorage length and increasing stirrup ratio,thickness of concrete cover,yield strength of reinforcing bar,concrete strength,which is similar to other base.Its bond stiffness is bigger and the degraded speed is slower than other base by the comparison of load-slip curves.
It is studied the main affection on bond performance between high-strength reinforcing bar and high-strength concrete by pull-out experiment of 48 specimens.It is analysed the causes of devastating phenomenon and compared to the classical load-slip curves of different base based on experiment.The test results revealed that its bond strength increases by decreasing anchorage length and increasing stirrup ratio,thickness of concrete cover,yield strength of reinforcing bar,concrete strength,which is similar to other base.Its bond stiffness is bigger and the degraded speed is slower than other base by the comparison of load-slip curves.
2007, 37(5): 82-87.
doi: 10.13204/j.gyjz200705021
Abstract:
The calculation methods to calculate load-bearing capacity of steel reinforced concrete(SRC) column are mostly based on calculation of the bearing capacity of reinforced concrete column,the allowable stress law of steel column and the superposed method.Four typical calculation methods respectively based on the above patterns provided by ACI-318-02 specification,AISC-LRFD design code,and the Specification for SRC structure(YB 9082-97) of China are introduced.According to a calculation example of load-bearing capacity of SRC eccentrically compressed,calculation method and steps of the four routine calculations pattern are presented.Load-bearing capacities of a series of SRC columns specimens tested before in references are also calculated using the method of the above specifications and codes,and comparison analysis between calculated results and test results are also conducted.It is denoted that among the four typical methods,the AISC-LRFD calculation method provides very conservative calculation results,calculation methods of the ACI specification and YB 9082-97 specification provides results close to the test results.
The calculation methods to calculate load-bearing capacity of steel reinforced concrete(SRC) column are mostly based on calculation of the bearing capacity of reinforced concrete column,the allowable stress law of steel column and the superposed method.Four typical calculation methods respectively based on the above patterns provided by ACI-318-02 specification,AISC-LRFD design code,and the Specification for SRC structure(YB 9082-97) of China are introduced.According to a calculation example of load-bearing capacity of SRC eccentrically compressed,calculation method and steps of the four routine calculations pattern are presented.Load-bearing capacities of a series of SRC columns specimens tested before in references are also calculated using the method of the above specifications and codes,and comparison analysis between calculated results and test results are also conducted.It is denoted that among the four typical methods,the AISC-LRFD calculation method provides very conservative calculation results,calculation methods of the ACI specification and YB 9082-97 specification provides results close to the test results.
2007, 37(5): 88-93.
doi: 10.13204/j.gyjz200705022
Abstract:
Hollow flange beam(HFB) has particular cross section with two torsionally rigid closed triangular flanges and a comparatively flexible web,it is a type of high efficient cross section mainly used as flexural members.Based on the HFB section,it is put forward that two new kinds of cold-formed flange-closed welding sections named HF1 and HF2 through changing the component of section and section parameters of HFB.It is also presented a finite element analytical model suitable for non-linear analysis of HFB flexural members.The model includes all significant effects that may influence the ultimate capacity of such members,including material inelasticity,local buckling,member instability,web distortion,and geometric imperfections.On the base of precise finite element model,nonlinear finite element method is adopted to study the new sections' buckling modes,relative deflection,moment-curvature curves,and ultimate capacity.The static behaviors of the two kinds of sections are analyzed completely.It can be concluded that the new sections have the well characteristic of high rigidity,high ultimate capacity,local buckling of the sections always hard to occur,and can go deep into the experiment study as to be used in the practical engineering.
Hollow flange beam(HFB) has particular cross section with two torsionally rigid closed triangular flanges and a comparatively flexible web,it is a type of high efficient cross section mainly used as flexural members.Based on the HFB section,it is put forward that two new kinds of cold-formed flange-closed welding sections named HF1 and HF2 through changing the component of section and section parameters of HFB.It is also presented a finite element analytical model suitable for non-linear analysis of HFB flexural members.The model includes all significant effects that may influence the ultimate capacity of such members,including material inelasticity,local buckling,member instability,web distortion,and geometric imperfections.On the base of precise finite element model,nonlinear finite element method is adopted to study the new sections' buckling modes,relative deflection,moment-curvature curves,and ultimate capacity.The static behaviors of the two kinds of sections are analyzed completely.It can be concluded that the new sections have the well characteristic of high rigidity,high ultimate capacity,local buckling of the sections always hard to occur,and can go deep into the experiment study as to be used in the practical engineering.
2007, 37(5): 94-95.
doi: 10.13204/j.gyjz200705023
Abstract:
In negative moment region of composite frame beam,its design and the detail of struction are more complicated than that of simply supported composite beam,so it was seldom adopted in project.The test on a new-type composite frame beam is introduced.The testing results show that the composite frame beam is secure and reliable when adopted in the steel structure of residence.The design calculating values is conservative compared with those of the test.
In negative moment region of composite frame beam,its design and the detail of struction are more complicated than that of simply supported composite beam,so it was seldom adopted in project.The test on a new-type composite frame beam is introduced.The testing results show that the composite frame beam is secure and reliable when adopted in the steel structure of residence.The design calculating values is conservative compared with those of the test.
2007, 37(5): 96-99.
doi: 10.13204/j.gyjz200705024
Abstract:
Cable-strut steel arch is modeled by beam,truss and cable elements.To make clear the influence of such factors as strut number,strut length,prestress in cable and the rist to span ratio of arch etc on the loadcarrying performance of this kind of structure,parameter analysis is carried out with a mixed finite element program,from which some useful conclusions are drawn.
Cable-strut steel arch is modeled by beam,truss and cable elements.To make clear the influence of such factors as strut number,strut length,prestress in cable and the rist to span ratio of arch etc on the loadcarrying performance of this kind of structure,parameter analysis is carried out with a mixed finite element program,from which some useful conclusions are drawn.
2007, 37(5): 100-102.
doi: 10.13204/j.gyjz200705025
Abstract:
With the widespread application of Arched Corrugated Steel Roof(ACSR) in China,sometimes ACSR with unequal altitude support is applied in the practical projects,whose bearing capacity under vertical load is unknown.A 18mspan MMR-238 ACSR is taken as a research object.For ACSR with different ratio of rise to span,the influence of unequal altitude support to the bearing capacity under different vertical load is studied,by using ABAQUS finite element software.Under full-span vertical load,the ultimate bearing capacity of the ACSR with unequal altitude support reduced greatly compared with the equal altitude support situation.Under half-span vertical load,the influence of unequal support altitude is small to the structural ultimate bearing capacity.
With the widespread application of Arched Corrugated Steel Roof(ACSR) in China,sometimes ACSR with unequal altitude support is applied in the practical projects,whose bearing capacity under vertical load is unknown.A 18mspan MMR-238 ACSR is taken as a research object.For ACSR with different ratio of rise to span,the influence of unequal altitude support to the bearing capacity under different vertical load is studied,by using ABAQUS finite element software.Under full-span vertical load,the ultimate bearing capacity of the ACSR with unequal altitude support reduced greatly compared with the equal altitude support situation.Under half-span vertical load,the influence of unequal support altitude is small to the structural ultimate bearing capacity.
2007, 37(5): 103-105.
doi: 10.13204/j.gyjz200705026
Abstract:
In order to study the bonding performance of adhesive reinforcement of fire-injured concrete,a large numbers of shear experiments on Z-shape bonding specimens based on injured concrete subjected to elevated temperature were done.Shear slipping curves were measured under several circumstances such as different temperature,different cooling ways and different interfacial roughness.At same time,the corresponding calculation formulas are deduced and the feature of shear slipping curve is also generalized.The study will provide reference for numerical simulating calculation of bonding reinforcement.
In order to study the bonding performance of adhesive reinforcement of fire-injured concrete,a large numbers of shear experiments on Z-shape bonding specimens based on injured concrete subjected to elevated temperature were done.Shear slipping curves were measured under several circumstances such as different temperature,different cooling ways and different interfacial roughness.At same time,the corresponding calculation formulas are deduced and the feature of shear slipping curve is also generalized.The study will provide reference for numerical simulating calculation of bonding reinforcement.
2007, 37(5): 106-109.
doi: 10.13204/j.gyjz200705027
Abstract:
The detection of a 11-layers frame shear wall structure shows that the concrete strength of the seventh partial wall columns and the eighth partial beam and floor plate in that building are very low.For meeting the related nantional standards and avoiding demolishment of the building,the underpinning and strengthening methods are used,with which the loads of center column are underpined by the diagonal steel strut and the cross-sectional areas of side pillar are strengthened,both ends of shear wall are chiseled in turn and then concrete is poured again.
The detection of a 11-layers frame shear wall structure shows that the concrete strength of the seventh partial wall columns and the eighth partial beam and floor plate in that building are very low.For meeting the related nantional standards and avoiding demolishment of the building,the underpinning and strengthening methods are used,with which the loads of center column are underpined by the diagonal steel strut and the cross-sectional areas of side pillar are strengthened,both ends of shear wall are chiseled in turn and then concrete is poured again.
2007, 37(5): 110-113.
doi: 10.13204/j.gyjz200705028
Abstract:
The design and construction process of rectifying deviation of a six-story masonry building in Shanghai are presented.For traditional inclination rectification method of static bolt-pressing piles and drilling and drawing out soil,the piles are first jacked by anchor rods in the side of a building with larger settlement,then soil is drilled and drawn out in other side of the building.When the inclination building is rectified,some piles are jacked in the other side to prevent building from inclining.In this project,the piles were jacked while soil was drilled and drawn out.This shortened the construction time,and reduced the additional stress at pile top.And the additional settlement of building was allowed.
The design and construction process of rectifying deviation of a six-story masonry building in Shanghai are presented.For traditional inclination rectification method of static bolt-pressing piles and drilling and drawing out soil,the piles are first jacked by anchor rods in the side of a building with larger settlement,then soil is drilled and drawn out in other side of the building.When the inclination building is rectified,some piles are jacked in the other side to prevent building from inclining.In this project,the piles were jacked while soil was drilled and drawn out.This shortened the construction time,and reduced the additional stress at pile top.And the additional settlement of building was allowed.
