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2010 Vol. 40, No. 8
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2010, 40(8): 1-5,26.
doi: 10.13204/j.gyjz201008001
Abstract:
Cable supported structureis a clear definition for both structural members and features. Cable means the arched tension cables and supporteddenotes the effect of compression struts, while structure represents the upper layer in the whole structure. Based on introduction of structural concept, cable supported structures are defined as cable supported plane structure, separate cable supported spatial structure and inseparate cable supported spatial structure. Four new types of cable supported structures which are cable supported space trusses structure, cable supported concrete roof structure, cable supported barrel vault structure and cable supported arch-dome structure are presented in this paper. According to research work in this field of cable supported structure, three kinds of classifications which can be compatible to all research outcomes are proposed. The definition of cable supported structure is also recommended in this paper. Using this classification, cable supported structure can be defined as a clear integrity and can be applied in study, development and practice conveniently.
Cable supported structureis a clear definition for both structural members and features. Cable means the arched tension cables and supporteddenotes the effect of compression struts, while structure represents the upper layer in the whole structure. Based on introduction of structural concept, cable supported structures are defined as cable supported plane structure, separate cable supported spatial structure and inseparate cable supported spatial structure. Four new types of cable supported structures which are cable supported space trusses structure, cable supported concrete roof structure, cable supported barrel vault structure and cable supported arch-dome structure are presented in this paper. According to research work in this field of cable supported structure, three kinds of classifications which can be compatible to all research outcomes are proposed. The definition of cable supported structure is also recommended in this paper. Using this classification, cable supported structure can be defined as a clear integrity and can be applied in study, development and practice conveniently.
2010, 40(8): 6-9.
doi: 10.13204/j.gyjz201008002
Abstract:
Space truss structure is widely applied in practical engineering as a space structure. Based on traditional pre-stressing space truss structure,the concept of tensegrity system is introduced into space truss structure to form a cable supported space truss structure is formed and its architectural effect is superior. Classification form of the cable supported space truss structure is given. It is comparatively studied the characteristics of the cable supported space truss structure and the space truss string structure,the concept of the evacuation cable supported space truss structure is proposed. The static and dynamic behavior of the evacuation cable supported space truss structure is researched.At last,characteristics and application of the cable supported evacuation space truss structure are introduced.
Space truss structure is widely applied in practical engineering as a space structure. Based on traditional pre-stressing space truss structure,the concept of tensegrity system is introduced into space truss structure to form a cable supported space truss structure is formed and its architectural effect is superior. Classification form of the cable supported space truss structure is given. It is comparatively studied the characteristics of the cable supported space truss structure and the space truss string structure,the concept of the evacuation cable supported space truss structure is proposed. The static and dynamic behavior of the evacuation cable supported space truss structure is researched.At last,characteristics and application of the cable supported evacuation space truss structure are introduced.
2010, 40(8): 10-12.
doi: 10.13204/j.gyjz201008003
Abstract:
Based on summarizing the mechanical characteristics of arch-supported reticulated shell structures,the concept of tensigrity system is introduced into the arch-supported reticulated shell,which as solved the problems of large reaction of the support in an arch-supported reticulated shell,as well as the difficulty in the design of a bearing structure. It is also analyzed the static behavior and stability of a cable supported arch-dome structure combined with an actual project. The introduction of tensigrity can decrease greatly the support reaction of the arch-supported reticulated shell structure and also inpove its stability. The basic dynamic characteristics of the two types of structures are compared,with which stiffness and natural frequency of vibration are got.
Based on summarizing the mechanical characteristics of arch-supported reticulated shell structures,the concept of tensigrity system is introduced into the arch-supported reticulated shell,which as solved the problems of large reaction of the support in an arch-supported reticulated shell,as well as the difficulty in the design of a bearing structure. It is also analyzed the static behavior and stability of a cable supported arch-dome structure combined with an actual project. The introduction of tensigrity can decrease greatly the support reaction of the arch-supported reticulated shell structure and also inpove its stability. The basic dynamic characteristics of the two types of structures are compared,with which stiffness and natural frequency of vibration are got.
2010, 40(8): 13-15,19.
doi: 10.13204/j.gyjz201008004
Abstract:
The conception of cable-supported vault structure was put forward by introducing the idea of cablesupport into column-reticulated shell structure. The composition of cable-supported vault structure was analyzed.Two classification methods were presented,respectively on the basis of layer number of barrel vault structure and the grid arrangement. It was analyzed the merit of cable-supported barrel vault structure as compared with a single-layer column-reticulated shell structure. The general situation and characteristic of two actual projects were summarized, which are Liaoning Huafu Print Works and dry coal shed for Dagang Power station in Tianjin. The feasibility of adopting cable-supported vault structure was pointed out. And design procedure and effect of employing cablesupported vault structure in the two projects were also described.
The conception of cable-supported vault structure was put forward by introducing the idea of cablesupport into column-reticulated shell structure. The composition of cable-supported vault structure was analyzed.Two classification methods were presented,respectively on the basis of layer number of barrel vault structure and the grid arrangement. It was analyzed the merit of cable-supported barrel vault structure as compared with a single-layer column-reticulated shell structure. The general situation and characteristic of two actual projects were summarized, which are Liaoning Huafu Print Works and dry coal shed for Dagang Power station in Tianjin. The feasibility of adopting cable-supported vault structure was pointed out. And design procedure and effect of employing cablesupported vault structure in the two projects were also described.
2010, 40(8): 16-19.
doi: 10.13204/j.gyjz201008005
Abstract:
Supported barrel vault is a new type of prestressed structure,its origin is combining tensigrity system concept with single-layer lattice shell. It is necessary to analyze the reliability of the barrel vault structure and check up whether the value of reliability meets the requirements of codes,which is the key to forming a reasonable and effective system. Based on probability theory and sensitivity analysis method,this paper discusses the influences of main parameters on its reliability,carries out the sensitivity of all parameters,fits reliability index formula and finally obtains the target reliability index under applicability conditions.
Supported barrel vault is a new type of prestressed structure,its origin is combining tensigrity system concept with single-layer lattice shell. It is necessary to analyze the reliability of the barrel vault structure and check up whether the value of reliability meets the requirements of codes,which is the key to forming a reasonable and effective system. Based on probability theory and sensitivity analysis method,this paper discusses the influences of main parameters on its reliability,carries out the sensitivity of all parameters,fits reliability index formula and finally obtains the target reliability index under applicability conditions.
2010, 40(8): 20-26.
doi: 10.13204/j.gyjz201008006
Abstract:
Cable supported plane structure is widely accepted and applied in practical engineering as a new prestressing long-span spatial structure. Research status of the cable supported plane structure,such as form-finding analysis,static and dynamic behaviors,construction process and so on,are reviewed,and the characteristics of all research methods were also analyzed. The overviews of the typical projects were made. Combined with disasters of severe snow in the recent years,the elastoplastic ultimate development of the cable supported plane structure is simulated by the finite element method. The yielding mechanism and the failure mechanism of the cable supported plane structure are obtained under snow load over all span and under semi-cross snow load. The development of plasticity and the redistribution of internal force of the cable supported plane structure are summarized,which provide a theoretic basis for the analysis and design of actual projects under beyond snow load.
Cable supported plane structure is widely accepted and applied in practical engineering as a new prestressing long-span spatial structure. Research status of the cable supported plane structure,such as form-finding analysis,static and dynamic behaviors,construction process and so on,are reviewed,and the characteristics of all research methods were also analyzed. The overviews of the typical projects were made. Combined with disasters of severe snow in the recent years,the elastoplastic ultimate development of the cable supported plane structure is simulated by the finite element method. The yielding mechanism and the failure mechanism of the cable supported plane structure are obtained under snow load over all span and under semi-cross snow load. The development of plasticity and the redistribution of internal force of the cable supported plane structure are summarized,which provide a theoretic basis for the analysis and design of actual projects under beyond snow load.
2010, 40(8): 27-29,34.
doi: 10.13204/j.gyjz201008007
Abstract:
It is summarized the current methods of suspend-dome construction,the loss of prestress in loop cable caused by friction is studied in this paper. A new kind of roll cable-strut joint with a bearing is put forward to deal with the problem. Loss of prestress is reduced because of gliding friction replaced by roll friction. Two designs of roll cable-strut joint single-part roll cable-strut joint and press broad roll cable-strut joint are given under the concept of roll axis,as well as an actual design based on a suspend-dome model test. A kind of cable-strut joint which allows sliding of cable in prestress process and fixes the cable after construction is declared in different ways.
It is summarized the current methods of suspend-dome construction,the loss of prestress in loop cable caused by friction is studied in this paper. A new kind of roll cable-strut joint with a bearing is put forward to deal with the problem. Loss of prestress is reduced because of gliding friction replaced by roll friction. Two designs of roll cable-strut joint single-part roll cable-strut joint and press broad roll cable-strut joint are given under the concept of roll axis,as well as an actual design based on a suspend-dome model test. A kind of cable-strut joint which allows sliding of cable in prestress process and fixes the cable after construction is declared in different ways.
2010, 40(8): 30-34.
doi: 10.13204/j.gyjz201008008
Abstract:
Based on the tensegrity and cable supported structures,the cable supported concrete roof structure was put forward as a new-style pre-stressed compound steel-concrete roof structure. It has advantages of larger span,simple construction,high industrialization. But using the method of increasing the thickness of precast concrete panel to enhance stiffness can also caused a rise in the structure weight. Concrete sandwich board with wire mesh is a new light building board,which has the features of light weight,high rigidity and good bearing capacity. And thereby,this paper propose the idea of cable supported concrete sandwich board with wire mesh,its basic characteristics,such as the pre-stress design of the cable,the behavior of natural oscillation and the crack control of concrete sandwich board with wire mesh were studied by using the finite element software.
Based on the tensegrity and cable supported structures,the cable supported concrete roof structure was put forward as a new-style pre-stressed compound steel-concrete roof structure. It has advantages of larger span,simple construction,high industrialization. But using the method of increasing the thickness of precast concrete panel to enhance stiffness can also caused a rise in the structure weight. Concrete sandwich board with wire mesh is a new light building board,which has the features of light weight,high rigidity and good bearing capacity. And thereby,this paper propose the idea of cable supported concrete sandwich board with wire mesh,its basic characteristics,such as the pre-stress design of the cable,the behavior of natural oscillation and the crack control of concrete sandwich board with wire mesh were studied by using the finite element software.
2010, 40(8): 35-41.
doi: 10.13204/j.gyjz201008009
Abstract:
Cable supported structure systems are applied more and more in significant public buildings,but there is less systematic study on the aspects of construction method at home and abroad at present. This paper analyzes and summarized the construction technologies of cable supported plane structure,decomposable spatial cable supported structure and indecomposable cable supported spatial structure respectively,as well as further explores the hoisting method of steel structure,cable tension method and other construction technology,puts forward the problems needing attention and those to be studied in the field of construction technology for different kinds of structures.
Cable supported structure systems are applied more and more in significant public buildings,but there is less systematic study on the aspects of construction method at home and abroad at present. This paper analyzes and summarized the construction technologies of cable supported plane structure,decomposable spatial cable supported structure and indecomposable cable supported spatial structure respectively,as well as further explores the hoisting method of steel structure,cable tension method and other construction technology,puts forward the problems needing attention and those to be studied in the field of construction technology for different kinds of structures.
2010, 40(8): 42-48.
doi: 10.13204/j.gyjz201008010
Abstract:
Suspen-dome structures,as new pre-stressing spatial structures,have been applied in about twenty projects in the world due to its highly-efficient structural mechanism and beautiful appearance. In this paper,some main information of suspen-dome projects were summarized such as span,type of upper dome,type of bottom tensegrity systems,pre-stressing method,upper joint of strut,bottom joint of strut and so on. Based on which,some analyses were carried out on the design method of pre-stressing,joints design,pre-stressing method and model tests,and some suggestions that would be a reference for projects were put forward.
Suspen-dome structures,as new pre-stressing spatial structures,have been applied in about twenty projects in the world due to its highly-efficient structural mechanism and beautiful appearance. In this paper,some main information of suspen-dome projects were summarized such as span,type of upper dome,type of bottom tensegrity systems,pre-stressing method,upper joint of strut,bottom joint of strut and so on. Based on which,some analyses were carried out on the design method of pre-stressing,joints design,pre-stressing method and model tests,and some suggestions that would be a reference for projects were put forward.
2010, 40(8): 49-53,77.
doi: 10.13204/j.gyjz201008011
Abstract:
Ecoclimatic building design has roots in local climate and natural environment,which laid the foundation for ecology and energy-saving. Using the methods of graphic analysis and inductive synthesis,the principles and strategies that architectural design integrated with local climate and eco-environment were discussed. Architectural design with ecoclimate should control advantageous climate and natural landform,avoid disadvantageous climate by planning and architectural design,and take appropriate technologies and vernacular architectural aesthetics to make indoor thermal environment cool in summer and warm in winter; at the same time architectural layout,spatial form,thermal buffer space,ventilation and windproof,shape selection and energy-saving structure should all follow regional climate.
Ecoclimatic building design has roots in local climate and natural environment,which laid the foundation for ecology and energy-saving. Using the methods of graphic analysis and inductive synthesis,the principles and strategies that architectural design integrated with local climate and eco-environment were discussed. Architectural design with ecoclimate should control advantageous climate and natural landform,avoid disadvantageous climate by planning and architectural design,and take appropriate technologies and vernacular architectural aesthetics to make indoor thermal environment cool in summer and warm in winter; at the same time architectural layout,spatial form,thermal buffer space,ventilation and windproof,shape selection and energy-saving structure should all follow regional climate.
2010, 40(8): 54-56.
doi: 10.13204/j.gyjz201008012
Abstract:
This paper analyzes the features of the building energy-saving system from the viewpoint of the systematic perspective. It is considered that certain coupling correlations exist among the elements in the system. In accordance with this coupling correlation,the concurrent subsystem optimization method,which is suitable for the building energy-saving system design,is put forward by adopting relevant theories and methodologies of the multidisciplinary design optimization. Meanwhile,the characteristics and the process of this method are also elaborated in this paper.
This paper analyzes the features of the building energy-saving system from the viewpoint of the systematic perspective. It is considered that certain coupling correlations exist among the elements in the system. In accordance with this coupling correlation,the concurrent subsystem optimization method,which is suitable for the building energy-saving system design,is put forward by adopting relevant theories and methodologies of the multidisciplinary design optimization. Meanwhile,the characteristics and the process of this method are also elaborated in this paper.
2010, 40(8): 57-60.
doi: 10.13204/j.gyjz201008013
Abstract:
For the industrial buildings in the extremely cold and cold regions in China, the space heating has a considerable proportion in their total energy consumption. Traditional space heating has disadvantages from both energy consumption and environment. The renewable energy technology: solar space heating technology has the potential to develop. This paper introduced this technology and studied the critical issues including heating storage, insulation and collector tilt angle. The characteristics and advantages of concrete slab storage and facade installation were revealed. The results may be a reference for popularizing this technology.
For the industrial buildings in the extremely cold and cold regions in China, the space heating has a considerable proportion in their total energy consumption. Traditional space heating has disadvantages from both energy consumption and environment. The renewable energy technology: solar space heating technology has the potential to develop. This paper introduced this technology and studied the critical issues including heating storage, insulation and collector tilt angle. The characteristics and advantages of concrete slab storage and facade installation were revealed. The results may be a reference for popularizing this technology.
2010, 40(8): 61-63.
doi: 10.13204/j.gyjz201008014
Abstract:
This paper combines the sustainable development with the situation of rural areas in China. It begins with the analysis of the importance of building energy conservation of rural areas in China. Then it is pointed out that renewable energy, such as solar energy, biogas energy should be the future developing direction of the new energy sources in rural areas. Finally, it is illustrated the main energy-saving measures for the residential buildings in rural areas.
This paper combines the sustainable development with the situation of rural areas in China. It begins with the analysis of the importance of building energy conservation of rural areas in China. Then it is pointed out that renewable energy, such as solar energy, biogas energy should be the future developing direction of the new energy sources in rural areas. Finally, it is illustrated the main energy-saving measures for the residential buildings in rural areas.
2010, 40(8): 64-68.
doi: 10.13204/j.gyjz201008015
Abstract:
A new type of prestressed concrete composite beam( double prestressed composite beam)was introduced, its design feature was analyzed. The new type prestressed concrete composite beam was proposed to be applied to high-speed railway ballastless track bridge. Whose stresses in different construction stages were analyzed according to the design of an actual project and contrasted to conventional prestressed concrete beam. The results show double prestressed composite beam has a smaller stress gradient which is propitious to decrease the creep camber of prestressed concrete beam; about 10% of the tendon can be saved by the double prestressed composite beam, which has obvious economic advantages.
A new type of prestressed concrete composite beam( double prestressed composite beam)was introduced, its design feature was analyzed. The new type prestressed concrete composite beam was proposed to be applied to high-speed railway ballastless track bridge. Whose stresses in different construction stages were analyzed according to the design of an actual project and contrasted to conventional prestressed concrete beam. The results show double prestressed composite beam has a smaller stress gradient which is propitious to decrease the creep camber of prestressed concrete beam; about 10% of the tendon can be saved by the double prestressed composite beam, which has obvious economic advantages.
2010, 40(8): 69-73.
doi: 10.13204/j.gyjz201008016
Abstract:
In order to preferably analyze damage mechanism of steel reinforced high strength and high performance concrete (SRHSHPC) columns subjected to seismic load, by comparing and analyzing the current several seismic damage models and based on hysteretic characteristics of SRHSHPC columns under low cyclic loading, it is established a seismic damage model suitable for SRHSHPC columns, which takes unloading stiffness degradation corresponding to maximum deformation and accumulated residual plastic deformation as damage parameters.Furthermore, based on existing experimental results, nonlinear regression analysis to damage model is made to determine related parameters of the model. Meanwhile, the influence of shear-span ratio, concrete strength and axialcompression ratio on the damage accumulation and development of SRHSHPC columns are analyzed. The results show that the damage of SRHSHPC columns develops faster with increasing of concrete strength and axial compression ratio during late loading stage; however, the ductility of SRHSHPC columns becomes better and the damage process becomes more smoothly with increasing of shear span ratio.
In order to preferably analyze damage mechanism of steel reinforced high strength and high performance concrete (SRHSHPC) columns subjected to seismic load, by comparing and analyzing the current several seismic damage models and based on hysteretic characteristics of SRHSHPC columns under low cyclic loading, it is established a seismic damage model suitable for SRHSHPC columns, which takes unloading stiffness degradation corresponding to maximum deformation and accumulated residual plastic deformation as damage parameters.Furthermore, based on existing experimental results, nonlinear regression analysis to damage model is made to determine related parameters of the model. Meanwhile, the influence of shear-span ratio, concrete strength and axialcompression ratio on the damage accumulation and development of SRHSHPC columns are analyzed. The results show that the damage of SRHSHPC columns develops faster with increasing of concrete strength and axial compression ratio during late loading stage; however, the ductility of SRHSHPC columns becomes better and the damage process becomes more smoothly with increasing of shear span ratio.
2010, 40(8): 74-77.
doi: 10.13204/j.gyjz201008017
Abstract:
One stadium roof structure consists of ladder-type elliptical paraboloid latticed shell with the form of double-layer Kewitte. The members of lower chord in the top layer keep continuous with the members of upper chord in the bottom layer. The state of these members turned from tension into press in the process of force transmission. It was studied the overall stability using linear and nonlinear buckling analyses. Some members of the shell had turned into plastic state before the critical point of buckling. But the structure still remained the carrying capacity simultaneously. The elastic-plasticity buckling began from the members of the overlap between the top layer and the bottom layer of the shell. The yield members lost the carrying capacity for load increment, which led to the overall buckling.
One stadium roof structure consists of ladder-type elliptical paraboloid latticed shell with the form of double-layer Kewitte. The members of lower chord in the top layer keep continuous with the members of upper chord in the bottom layer. The state of these members turned from tension into press in the process of force transmission. It was studied the overall stability using linear and nonlinear buckling analyses. Some members of the shell had turned into plastic state before the critical point of buckling. But the structure still remained the carrying capacity simultaneously. The elastic-plasticity buckling began from the members of the overlap between the top layer and the bottom layer of the shell. The yield members lost the carrying capacity for load increment, which led to the overall buckling.
2010, 40(8): 78-81.
doi: 10.13204/j.gyjz201008018
Abstract:
Slab transform floor of the high-rise building is an important part of building, formwork supporting system is pivotal, because it has direct relation to the quality of engineering construction. By exploring the selection of model for R. C transfer floor fastener falsework, it is conducted a numerical analysis of stability capacity of falsework. The paper described the various bars on the falsework internal force distribution and the effect of bracing angle on the overall stability of the bearing capacity and preventive and improvement measures are also proposed. Which provides a pratical guide for design and construction of conversion layer on falsework, and a reference for similar projects.
Slab transform floor of the high-rise building is an important part of building, formwork supporting system is pivotal, because it has direct relation to the quality of engineering construction. By exploring the selection of model for R. C transfer floor fastener falsework, it is conducted a numerical analysis of stability capacity of falsework. The paper described the various bars on the falsework internal force distribution and the effect of bracing angle on the overall stability of the bearing capacity and preventive and improvement measures are also proposed. Which provides a pratical guide for design and construction of conversion layer on falsework, and a reference for similar projects.
2010, 40(8): 82-85,90.
doi: 10.13204/j.gyjz201008019
Abstract:
In order to systematically comprehend and summarize the theories and procedures involved in the slope stability analysis based on limit equilibrium method,the traditional limit equilibrium methods of slices,the local factor of safety method based on Pans maximum principle, and critical slip field method were adopted in the slope stability analysis problems. Summaries on several procedures and strategies included in the slope stability analysis using limit equilibrium method were conducted,which were classified into three dual optimization problems. The details regarding each dual problem were described and were demonstrated. This work may be beneficial to the further development of limit equilibrium method.
In order to systematically comprehend and summarize the theories and procedures involved in the slope stability analysis based on limit equilibrium method,the traditional limit equilibrium methods of slices,the local factor of safety method based on Pans maximum principle, and critical slip field method were adopted in the slope stability analysis problems. Summaries on several procedures and strategies included in the slope stability analysis using limit equilibrium method were conducted,which were classified into three dual optimization problems. The details regarding each dual problem were described and were demonstrated. This work may be beneficial to the further development of limit equilibrium method.
2010, 40(8): 86-90.
doi: 10.13204/j.gyjz201008020
Abstract:
Problems of one-dimensional thermal consolidation of saturated soil under periodic fluctuation of surface temperature were investigated theoretically by establishing the thermal consolidation model. The analytical solutions of excess pore water pressure,temperature increment were deduced by the theory of partial differential equations,and the expressions of settlement were also given. One-dimensional thermal consolidation behaviour of saturated soil was investigated by comparing with the Terzaghi consolidation solution. The results shows that the behaviour of thermal consolidation is affected greatly by the temperature which is embodied by the temperature increase, the rate of heat conduction and period of temperature fluctuation. Under periodic fluctuation of surface temperature,there will be a fluctuation in the behaviour of excess pore-water pressure and settlement in the process of thermal consolidation.
Problems of one-dimensional thermal consolidation of saturated soil under periodic fluctuation of surface temperature were investigated theoretically by establishing the thermal consolidation model. The analytical solutions of excess pore water pressure,temperature increment were deduced by the theory of partial differential equations,and the expressions of settlement were also given. One-dimensional thermal consolidation behaviour of saturated soil was investigated by comparing with the Terzaghi consolidation solution. The results shows that the behaviour of thermal consolidation is affected greatly by the temperature which is embodied by the temperature increase, the rate of heat conduction and period of temperature fluctuation. Under periodic fluctuation of surface temperature,there will be a fluctuation in the behaviour of excess pore-water pressure and settlement in the process of thermal consolidation.
2010, 40(8): 91-94.
doi: 10.13204/j.gyjz201008021
Abstract:
Underground pipelines play a decisive role in maintaining the functions of modern cities and regional economies. There are still less researches on the aseismic performance of underground pipelines as compared with theoretic ones. Two layered soil shear sandboxes of same design are used to simulate the boundary conditions of the soil. It is explored the dynamic response law of underground pipelines subjected to non-uniform excitations by means of base input. It is also examined the effect of change in many factors on pipeline-soil interaction by changing the diameter and depth of pipes,adjusting the frequency and amplitude of the base input.
Underground pipelines play a decisive role in maintaining the functions of modern cities and regional economies. There are still less researches on the aseismic performance of underground pipelines as compared with theoretic ones. Two layered soil shear sandboxes of same design are used to simulate the boundary conditions of the soil. It is explored the dynamic response law of underground pipelines subjected to non-uniform excitations by means of base input. It is also examined the effect of change in many factors on pipeline-soil interaction by changing the diameter and depth of pipes,adjusting the frequency and amplitude of the base input.
2010, 40(8): 95-98,60.
doi: 10.13204/j.gyjz201008022
Abstract:
It is very easy to lead to off-center hitting when the gravity center of hammer and the top of the pile is not right or the drop hammer device frame is not vertical in a high strain dynamic test,which then produces a significant impact on the signals of sensors that are on a hammer and the side of a pile. This paper made simulation study of offcenter hitting for high strain dynamic test piles based on two different installation methods of sensors; it was analyzed in detail the reasonableness of two kinds of high strain dynamic tests and their correct installation schemes with an emphasis on the effects of off-center hitting to the speed of each part and strain of the pile. The simulation explains the phenomena found in the practice such as the strain severely affected by off-center hitting,and less impact on the speed,which corrects the misconception that big piles need more sensors to over the impact of the off-center hitting.
It is very easy to lead to off-center hitting when the gravity center of hammer and the top of the pile is not right or the drop hammer device frame is not vertical in a high strain dynamic test,which then produces a significant impact on the signals of sensors that are on a hammer and the side of a pile. This paper made simulation study of offcenter hitting for high strain dynamic test piles based on two different installation methods of sensors; it was analyzed in detail the reasonableness of two kinds of high strain dynamic tests and their correct installation schemes with an emphasis on the effects of off-center hitting to the speed of each part and strain of the pile. The simulation explains the phenomena found in the practice such as the strain severely affected by off-center hitting,and less impact on the speed,which corrects the misconception that big piles need more sensors to over the impact of the off-center hitting.
2010, 40(8): 99-102.
doi: 10.13204/j.gyjz201008023
Abstract:
To investigate the influence of joint core volume reinforcement ratio and axial compression ratio on crack behavior of ultra high toughness cementitious composite(UHTCC) joints,nine specimens of UHTCC beam-column joints were tested under reversed low cyclic loading. The results showed that UHTCC could effectively control crack width and increase axial compression ratio,which could raise the crack resistance capacity of the joint. Based on the test results,a theoretical formula of crack resistance capacity was proposed. The calculated results were compared with those of the test,and a good agreement was obtained.
To investigate the influence of joint core volume reinforcement ratio and axial compression ratio on crack behavior of ultra high toughness cementitious composite(UHTCC) joints,nine specimens of UHTCC beam-column joints were tested under reversed low cyclic loading. The results showed that UHTCC could effectively control crack width and increase axial compression ratio,which could raise the crack resistance capacity of the joint. Based on the test results,a theoretical formula of crack resistance capacity was proposed. The calculated results were compared with those of the test,and a good agreement was obtained.
2010, 40(8): 103-106,81.
doi: 10.13204/j.gyjz201008024
Abstract:
The effects of curing time,binder strength,slot size and surface treatment on the bond strength were further studied. Pullout tests of 36 specimens were conducted to study the bond strength of the CFRP rods,and then four different bond materials were compared. During the experiment process,the failure modes,the slip between the CFRP and concrete and the cracking type were studied in detail. From the experimental study,it could be found that the influences on bond strength of binder strength,slot size and carbon fiber reinforced surface treatment technology were significant,but the curing time was small or neglected. The bond properties of epoxy mortar which made by quartz sand was excellent,which would be worth while popularizing.
The effects of curing time,binder strength,slot size and surface treatment on the bond strength were further studied. Pullout tests of 36 specimens were conducted to study the bond strength of the CFRP rods,and then four different bond materials were compared. During the experiment process,the failure modes,the slip between the CFRP and concrete and the cracking type were studied in detail. From the experimental study,it could be found that the influences on bond strength of binder strength,slot size and carbon fiber reinforced surface treatment technology were significant,but the curing time was small or neglected. The bond properties of epoxy mortar which made by quartz sand was excellent,which would be worth while popularizing.
2010, 40(8): 107-113,127.
doi: 10.13204/j.gyjz201008025
Abstract:
The study of the present paper was derived from the construction practice of thin-slab structures under high temperature in Guangdong Province. Via a series of experiments combined with the related theoretical analyses on the compatibility between concrete admixtures and cement,effect of the air void on the various performances of airentrained concrete such as bleeding,crack resistance,deformation,thermal characteristics and the like,this study optimized the mix proportions for slip-formed concrete thin-slab construction. Furthermore,it presented several proposals for construction control of slip-formed air-entrained concrete thin-slab structures. These proposals may serve as technical references for those who are in charge of the construction control.
The study of the present paper was derived from the construction practice of thin-slab structures under high temperature in Guangdong Province. Via a series of experiments combined with the related theoretical analyses on the compatibility between concrete admixtures and cement,effect of the air void on the various performances of airentrained concrete such as bleeding,crack resistance,deformation,thermal characteristics and the like,this study optimized the mix proportions for slip-formed concrete thin-slab construction. Furthermore,it presented several proposals for construction control of slip-formed air-entrained concrete thin-slab structures. These proposals may serve as technical references for those who are in charge of the construction control.
2010, 40(8): 114-117.
doi: 10.13204/j.gyjz201008026
Abstract:
Rammed concrete pile is the new development of columnar-hammer rammed and expanded piles. Owning to the twice compaction effect and high strength of rammed concrete,the rammed concrete pile has the advantages of high bearing capacity and low cost. Bearing behavior and construction procedure of rammed concrete piles are studied in the paper. The results of site tests indicate that the tube must be taken to drive the pile and ram the concrete under ground water level. The construction parameters are also analyzed.
Rammed concrete pile is the new development of columnar-hammer rammed and expanded piles. Owning to the twice compaction effect and high strength of rammed concrete,the rammed concrete pile has the advantages of high bearing capacity and low cost. Bearing behavior and construction procedure of rammed concrete piles are studied in the paper. The results of site tests indicate that the tube must be taken to drive the pile and ram the concrete under ground water level. The construction parameters are also analyzed.
2010, 40(8): 118-122.
doi: 10.13204/j.gyjz201008027
Abstract:
The Wuxi Technology Center has a special,complex ever-changing steel roof structure,which is highly hard to be constructed. Installation planning is formulated according to steel installation characteristic of the project.The main procedures of the construction program are as follows: the truss is installed first to form a closed construction area; and then the members of the network shell are erected,three closure mouths are set apart; the last part of the installation is the cable domes. So the quincuncial steel roof can be installed accurately.
The Wuxi Technology Center has a special,complex ever-changing steel roof structure,which is highly hard to be constructed. Installation planning is formulated according to steel installation characteristic of the project.The main procedures of the construction program are as follows: the truss is installed first to form a closed construction area; and then the members of the network shell are erected,three closure mouths are set apart; the last part of the installation is the cable domes. So the quincuncial steel roof can be installed accurately.
2010, 40(8): 123-127.
doi: 10.13204/j.gyjz201008028
Abstract:
It was analyzed the construction difficulties of this sort of shear wall for the swimming and diving hall of Qingdao Yizhong Stadium in the light of its features; it was also explored the quality problems during construction of the shear wall using current methods. Finally it was proposed a new construction technology of the shear wall,i. e.the method oftwo-way and four control lines,after summarizing current construction technologies. With which multicontrol measure could be used for its quality control. It is simple and convenient for operation,and is proved effective in practice.
It was analyzed the construction difficulties of this sort of shear wall for the swimming and diving hall of Qingdao Yizhong Stadium in the light of its features; it was also explored the quality problems during construction of the shear wall using current methods. Finally it was proposed a new construction technology of the shear wall,i. e.the method oftwo-way and four control lines,after summarizing current construction technologies. With which multicontrol measure could be used for its quality control. It is simple and convenient for operation,and is proved effective in practice.
2010, 40(8): 128-131.
doi: 10.13204/j.gyjz201008029
Abstract:
When a tunnel crossing a big cave,the processes of monitoring and measurement are important and indispensable in tunnel construction. The work and the analysis based on it not only correctly reflect the stability of surrounding rock and treatment structure,but also optimize the tunnel support parameters as well. According to a big cave in highway tunnel project of Qinglian Expressway in Baixugong,it is studied monitoring contents and monitoring methods of karst tunnel excavation. Site monitoring and analysis are done for surrounding rock and treatment structure,whose results can be used for guiding site construction,thus guaranteeing the safety of tunnel,which can provide evidence for treatment design of karst tunnels.
When a tunnel crossing a big cave,the processes of monitoring and measurement are important and indispensable in tunnel construction. The work and the analysis based on it not only correctly reflect the stability of surrounding rock and treatment structure,but also optimize the tunnel support parameters as well. According to a big cave in highway tunnel project of Qinglian Expressway in Baixugong,it is studied monitoring contents and monitoring methods of karst tunnel excavation. Site monitoring and analysis are done for surrounding rock and treatment structure,whose results can be used for guiding site construction,thus guaranteeing the safety of tunnel,which can provide evidence for treatment design of karst tunnels.
2010, 40(8): 132-138,117.
doi: 10.13204/j.gyjz201008030
Abstract:
Reliability analyses are made for shear capacity of RC members designed by GB 500102002, ACI 31808, EN 1992-1-1: 2004 and CSA A23.32004. In the analyses, load, material strength and geometrical parameter are described by probability model and statistical parameters provided by relevant study reports and literatures. Model uncertainty of calculation formulae of shear capacity is determined based on the experimental results of shear capacity of 415 reinforced concrete members without stirrups and 178 members with stirrups at home and abroad. It is concluded that reliability index of shear of reinforced concrete members without or with stirrups designed according to the code in China is larger than that in Canada, but smaller than that in America which is largest for members with stirrups and Europe which is largest for members without stirrups. Most members basically meet the requirements of target reliability index, except for reinforced concrete members without stirrups under point loads based on Chinese, American, European and Canadian code and members with stirrups based on Chinese code.
Reliability analyses are made for shear capacity of RC members designed by GB 500102002, ACI 31808, EN 1992-1-1: 2004 and CSA A23.32004. In the analyses, load, material strength and geometrical parameter are described by probability model and statistical parameters provided by relevant study reports and literatures. Model uncertainty of calculation formulae of shear capacity is determined based on the experimental results of shear capacity of 415 reinforced concrete members without stirrups and 178 members with stirrups at home and abroad. It is concluded that reliability index of shear of reinforced concrete members without or with stirrups designed according to the code in China is larger than that in Canada, but smaller than that in America which is largest for members with stirrups and Europe which is largest for members without stirrups. Most members basically meet the requirements of target reliability index, except for reinforced concrete members without stirrups under point loads based on Chinese, American, European and Canadian code and members with stirrups based on Chinese code.
APPLICATION OF THE CARBON FIBER REINFORCED POLYMER IN ASEISMIC STRENGTHENING OF A HOSPITAL IN URUMQI
2010, 40(8): 139-141,148.
doi: 10.13204/j.gyjz201008031
Abstract:
Aseismic capacity can be improved by strengthening with carbon fiber reinforced polymer sheet for existing buildings. Taking a project for example, it is presented the determination of reform scheme of strengthening and the aeismic strengthening design of concrete column with CFRP, the variation of axial compression ratio for frame column before and after strengthening is computed. The results show that strengthening with CFRP can effectively improve the aeismic capacity of frame column. After strengthening, the existing building satisfied the application requirement.
Aseismic capacity can be improved by strengthening with carbon fiber reinforced polymer sheet for existing buildings. Taking a project for example, it is presented the determination of reform scheme of strengthening and the aeismic strengthening design of concrete column with CFRP, the variation of axial compression ratio for frame column before and after strengthening is computed. The results show that strengthening with CFRP can effectively improve the aeismic capacity of frame column. After strengthening, the existing building satisfied the application requirement.
2010, 40(8): 142-148.
doi: 10.13204/j.gyjz201008032
Abstract:
Tianjin R ＆ F Center is a landmark building of Xiaobailou district, 4 floors underground, 2200-metershigh towers up the ground. The structural system of the 54-storey apartment tower is steel brace framework-core tube structure system. The main lateral resistant structure of X direction is reinforced concrete tube, and of Y direction is a combination system of steel brace framework and reinforced concrete tube. The steel brace framework is a combination of rectangular concrete-filled steel tube columns, rectangular steel braces and H-shaped steel-concrete composition beam. For the super-tall building, different kinds of lateral resistant structures are used in X and Y directions, ratio of H/B of concrete filled steel tube column is beyond 2.0, it is presented in detail the structural systems and members.
Tianjin R ＆ F Center is a landmark building of Xiaobailou district, 4 floors underground, 2200-metershigh towers up the ground. The structural system of the 54-storey apartment tower is steel brace framework-core tube structure system. The main lateral resistant structure of X direction is reinforced concrete tube, and of Y direction is a combination system of steel brace framework and reinforced concrete tube. The steel brace framework is a combination of rectangular concrete-filled steel tube columns, rectangular steel braces and H-shaped steel-concrete composition beam. For the super-tall building, different kinds of lateral resistant structures are used in X and Y directions, ratio of H/B of concrete filled steel tube column is beyond 2.0, it is presented in detail the structural systems and members.
