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2004 Vol. 34, No. 4
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2004, 34(4): 1-4.
doi: 10.13204/j.gyjz200404001
Abstract:
Technique of structures strengthened with near surface mounted (NSM) FRP has been studied and applied widely in abroad recent years.This paper introduces the research and applications of this technology, discusses the characters of this technique, construction process, and some problems that merit attention in field application.NSM method is convenient and can prevent structures from fire or destruction of other factors. NSM method is effective and worthy of being researched and applied in our country.
Technique of structures strengthened with near surface mounted (NSM) FRP has been studied and applied widely in abroad recent years.This paper introduces the research and applications of this technology, discusses the characters of this technique, construction process, and some problems that merit attention in field application.NSM method is convenient and can prevent structures from fire or destruction of other factors. NSM method is effective and worthy of being researched and applied in our country.
2004, 34(4): 5-10.
doi: 10.13204/j.gyjz200404002
Abstract:
Near-surface mounted (NSM) FRP reinforcement is emerging as a promising technique for the strengthening of concrete structures, as it offers some real practical advantages over externally bonded FRP reinforcement. This paper presents a state-of-the-art review of the existing international research on NSM reinforcement.Topics covered include materials, bond behaviour, flexural strengthening tests and design recommendations. It provides a basis for further research and application in China.
Near-surface mounted (NSM) FRP reinforcement is emerging as a promising technique for the strengthening of concrete structures, as it offers some real practical advantages over externally bonded FRP reinforcement. This paper presents a state-of-the-art review of the existing international research on NSM reinforcement.Topics covered include materials, bond behaviour, flexural strengthening tests and design recommendations. It provides a basis for further research and application in China.
2004, 34(4): 11-14,4.
doi: 10.13204/j.gyjz200404003
Abstract:
Compared to the traditional structural materials, a carbon fiber reinforced polymer(CFRP) has advantages of light-weight, high-strength, long-maintenance and designable.Due to those properties, FRP is being used to develop CFRP pipes for the construction of the space frames.An experimental study on three groups of axially loaded CFRP pipes, which have different layers and lengths, is done to analyze the failure types and mechanism.Finally, advices on design are proposed of the CFRP pipes.
Compared to the traditional structural materials, a carbon fiber reinforced polymer(CFRP) has advantages of light-weight, high-strength, long-maintenance and designable.Due to those properties, FRP is being used to develop CFRP pipes for the construction of the space frames.An experimental study on three groups of axially loaded CFRP pipes, which have different layers and lengths, is done to analyze the failure types and mechanism.Finally, advices on design are proposed of the CFRP pipes.
2004, 34(4): 15-18,27.
doi: 10.13204/j.gyjz200404004
Abstract:
Fiber reinforced polymer(FRP) hollow slab is an innovated structural element applied to structure engineering recently.It has a considerable future application in civil engineering due to its favorable properties, such as light weight, corrosion resistance and rapid construction.It can be used in industrial mill buildings, floors, footbridges, bridges and their enclosures.The behavior of simple supported pultruded glass fiber reinforced polymer(GFRP) hollow slab is studied through a static loading test and finite element analysis.The deflection, the distribution of strain and the ultimate failure of the slab are analyzed.Base on the results, a simplified approach to determine the equivalent stiffness of FRP hollow slab that is the area-weighted mean depended on the section characteristic is presented.It considers the anisotropy and the different elastic modules of tension, bend and compression of FRP.The local buckling failure mode and the strength failure mode of the FRP deck are simulated, which provides a basis for the design and application of FRP hollow slab.
Fiber reinforced polymer(FRP) hollow slab is an innovated structural element applied to structure engineering recently.It has a considerable future application in civil engineering due to its favorable properties, such as light weight, corrosion resistance and rapid construction.It can be used in industrial mill buildings, floors, footbridges, bridges and their enclosures.The behavior of simple supported pultruded glass fiber reinforced polymer(GFRP) hollow slab is studied through a static loading test and finite element analysis.The deflection, the distribution of strain and the ultimate failure of the slab are analyzed.Base on the results, a simplified approach to determine the equivalent stiffness of FRP hollow slab that is the area-weighted mean depended on the section characteristic is presented.It considers the anisotropy and the different elastic modules of tension, bend and compression of FRP.The local buckling failure mode and the strength failure mode of the FRP deck are simulated, which provides a basis for the design and application of FRP hollow slab.
2004, 34(4): 19-21,30.
doi: 10.13204/j.gyjz200404005
Abstract:
The fatigue damage of a steel member is one of the main failure modes of the steel structures.Through the fatigue tests and the analysis of K weld of steel a member with tension-tension stress.It is concluded that sticking the CFRP on the weld of steel member can reduce the stress concentration of the weld, which improves the fatigue performance, such as the fatigue life of steel member evidently, which shows high engineering values of steel structural weld reinforced with CFRP.
The fatigue damage of a steel member is one of the main failure modes of the steel structures.Through the fatigue tests and the analysis of K weld of steel a member with tension-tension stress.It is concluded that sticking the CFRP on the weld of steel member can reduce the stress concentration of the weld, which improves the fatigue performance, such as the fatigue life of steel member evidently, which shows high engineering values of steel structural weld reinforced with CFRP.
2004, 34(4): 22-24,48.
doi: 10.13204/j.gyjz200404006
Abstract:
Concrete structure strengthened with carbon fiber reinforced plastic sheet(CFS) is a new retrofit method in the field of civil engineering. Three reinforced concrete beams and four pre-stressed concrete beams have been tested under fatigue load after they are strengthened with CFS. Based on experimental results, the strengthened beam's strength and rigidity don't decrease after 2 million fatigue loads, and the peeling and brittle rupture of sheet don't happen, which proves the reliability of the CFS in practice. The calculation formula of bending bearing capacty of the strengthened beam that is accord with railway standard have been proposed, whose calculated values show good agreement with the experimental data.
Concrete structure strengthened with carbon fiber reinforced plastic sheet(CFS) is a new retrofit method in the field of civil engineering. Three reinforced concrete beams and four pre-stressed concrete beams have been tested under fatigue load after they are strengthened with CFS. Based on experimental results, the strengthened beam's strength and rigidity don't decrease after 2 million fatigue loads, and the peeling and brittle rupture of sheet don't happen, which proves the reliability of the CFS in practice. The calculation formula of bending bearing capacty of the strengthened beam that is accord with railway standard have been proposed, whose calculated values show good agreement with the experimental data.
2004, 34(4): 25-27.
doi: 10.13204/j.gyjz200404007
Abstract:
In recent years CFRP is widely applied to the field of rehabilitation and retrofit of existing structure, which can effectively confine the deformation of the concrete so that the carrying capacity and ductility capability of the structure are increased remarkably.The uniform calculation formula of the conversion volume stirrup rate of CFRP is given.Based on the relevant design specifications.The basic calculation method of seismic strengthening for reinforced concrete columns is introduced, and calculation flow chart of seismic strengthening is designed and software design by Visual Basic is also realized.CFRP seismic strengthening design interface and calculation method of columns of Southeast University Deep Strengthening Soft System(SEU_DEEP) are introduced and one practical example is presented to illuminate in detail.
In recent years CFRP is widely applied to the field of rehabilitation and retrofit of existing structure, which can effectively confine the deformation of the concrete so that the carrying capacity and ductility capability of the structure are increased remarkably.The uniform calculation formula of the conversion volume stirrup rate of CFRP is given.Based on the relevant design specifications.The basic calculation method of seismic strengthening for reinforced concrete columns is introduced, and calculation flow chart of seismic strengthening is designed and software design by Visual Basic is also realized.CFRP seismic strengthening design interface and calculation method of columns of Southeast University Deep Strengthening Soft System(SEU_DEEP) are introduced and one practical example is presented to illuminate in detail.
2004, 34(4): 28-30.
doi: 10.13204/j.gyjz200404008
Abstract:
The characteristics of a green square is analyzed according to ecology;and the basic thought of constructing green squares is also proposed from the respects of water_saving, green illumination, pavement, afforestation and humanization design etc.
The characteristics of a green square is analyzed according to ecology;and the basic thought of constructing green squares is also proposed from the respects of water_saving, green illumination, pavement, afforestation and humanization design etc.
2004, 34(4): 31-32,35.
doi: 10.13204/j.gyjz200404009
Abstract:
The relation of systematical theory and energy efficiency of buildings was analyzed, and the irrationality of economic evaluation and energy evaluation on energy efficiency was expounded.Based on view of systematical theory, a systematical evaluation for energy efficiency was put forward so that the benefit of energy efficiency of buildings is evaluated comprehensively, thus leading it rightly.
The relation of systematical theory and energy efficiency of buildings was analyzed, and the irrationality of economic evaluation and energy evaluation on energy efficiency was expounded.Based on view of systematical theory, a systematical evaluation for energy efficiency was put forward so that the benefit of energy efficiency of buildings is evaluated comprehensively, thus leading it rightly.
2004, 34(4): 33-35.
doi: 10.13204/j.gyjz200404010
Abstract:
Based on the combustibility of building fire simulation test furnace developed independently, the testing method and program of simulated fire are designed. Some experimental study on adiabaticity and integrity etc of the light wall has been done. The paper presents limit of fire resistance of the light wall and provides a scientific basis for safety design of the light wall.
Based on the combustibility of building fire simulation test furnace developed independently, the testing method and program of simulated fire are designed. Some experimental study on adiabaticity and integrity etc of the light wall has been done. The paper presents limit of fire resistance of the light wall and provides a scientific basis for safety design of the light wall.
2004, 34(4): 36-39.
doi: 10.13204/j.gyjz200404011
Abstract:
The temperature deformation and stress of ultralong frame structures are the foundation of solving structures crack problem.Building a three dimensional FEM model with the general FEM software, the author does a parametric study with changing section dimension and thickness of column and board respectively.The internal force combinations of the structure under the action of dead load, live load and temperature effect are also compared, which has a practical significance for designing.
The temperature deformation and stress of ultralong frame structures are the foundation of solving structures crack problem.Building a three dimensional FEM model with the general FEM software, the author does a parametric study with changing section dimension and thickness of column and board respectively.The internal force combinations of the structure under the action of dead load, live load and temperature effect are also compared, which has a practical significance for designing.
2004, 34(4): 40-42,56.
doi: 10.13204/j.gyjz200404012
Abstract:
After nonlinear finite analysis method on prestressed concrete frame with cross column was studied, a quite correct and general method to describe the mechanical feature of a working prestressed concrete frame with cross column was obtained. And the computer programme was designed with FORTRAN90. After the programme was validated, the structure feature of prestressed concrete frame with cross column was compared with that of prestressed concrete frame with rectangular column by plenty of results by computer. Then the characteristics of the two structures are obtained.
After nonlinear finite analysis method on prestressed concrete frame with cross column was studied, a quite correct and general method to describe the mechanical feature of a working prestressed concrete frame with cross column was obtained. And the computer programme was designed with FORTRAN90. After the programme was validated, the structure feature of prestressed concrete frame with cross column was compared with that of prestressed concrete frame with rectangular column by plenty of results by computer. Then the characteristics of the two structures are obtained.
2004, 34(4): 43-45.
doi: 10.13204/j.gyjz200404013
Abstract:
The main failure modes of interior connection in RC slab_column are punching shear and flexural failure. Combining with the tests at home and abroad, the punching shear bearing capacity calculating formula of interior connection given by Code for Design of Concrete Stmctures(GB50010-2002)is verified. According to the calculating width of equivalent beam subjected to earthquake action that received by elastic analysis, the flexural beating capacity calculating formula of interior slab_column connections is proposed. At last, the judgment method for the two failure modes is presented.
The main failure modes of interior connection in RC slab_column are punching shear and flexural failure. Combining with the tests at home and abroad, the punching shear bearing capacity calculating formula of interior connection given by Code for Design of Concrete Stmctures(GB50010-2002)is verified. According to the calculating width of equivalent beam subjected to earthquake action that received by elastic analysis, the flexural beating capacity calculating formula of interior slab_column connections is proposed. At last, the judgment method for the two failure modes is presented.
2004, 34(4): 46-48.
doi: 10.13204/j.gyjz200404014
Abstract:
The ductility of a corner post for a concrete frame under combination forces of compression, bending, shearing and torsion, as well as the torsional stiffness of its specimen at cracking, yielding and ultimate state are studied according to the changes in axial pressure ratio and relative eccentricity.The forced behavior of the corner post is also summarized by statistic analyses, which provides a theoretical basis for actual design.
The ductility of a corner post for a concrete frame under combination forces of compression, bending, shearing and torsion, as well as the torsional stiffness of its specimen at cracking, yielding and ultimate state are studied according to the changes in axial pressure ratio and relative eccentricity.The forced behavior of the corner post is also summarized by statistic analyses, which provides a theoretical basis for actual design.
2004, 34(4): 49-52.
doi: 10.13204/j.gyjz200404015
Abstract:
The working mechanisms and design methods of anchor plates, one of the applicable tension foundations of tensile cable-membrane structures are introduced. Design approaches based on uplift capability are discussed and the appropriate methods are proposed.The safety factors and constructions of anchor plates are also introduced.
The working mechanisms and design methods of anchor plates, one of the applicable tension foundations of tensile cable-membrane structures are introduced. Design approaches based on uplift capability are discussed and the appropriate methods are proposed.The safety factors and constructions of anchor plates are also introduced.
2004, 34(4): 53-56.
doi: 10.13204/j.gyjz200404016
Abstract:
The spreading foundation's base reaction is a nonlinear distribution normally. The result of numerical analysis shows, for the spreading foundation on rock foundation, there has more notable features that the bas e reaction nonlinearly distributes, and its distribution pattern and change law are different from that on soils. The height of foundation decides the distribution pattern of the base reaction. Along with the increas ing of relative rigid from little to great, the bas e reaction centralizes in central section firstly, then transforms to near even distribution, then centralizes in edge.
The spreading foundation's base reaction is a nonlinear distribution normally. The result of numerical analysis shows, for the spreading foundation on rock foundation, there has more notable features that the bas e reaction nonlinearly distributes, and its distribution pattern and change law are different from that on soils. The height of foundation decides the distribution pattern of the base reaction. Along with the increas ing of relative rigid from little to great, the bas e reaction centralizes in central section firstly, then transforms to near even distribution, then centralizes in edge.
2004, 34(4): 57-60,72.
doi: 10.13204/j.gyjz200404017
Abstract:
As the technical cooperation and communication are frequent in the world, models for tunnel lining design are becoming unanimous, but the researches for appropriate computational models have never been stopped and more and more of them have been brought out. Accoring to tunnel construction steps, contact surface between segments and soil and stress releasing, 2D-FEM is put forward to simulate shield tunnel construction.The conclusion and methods can provide valuable preference for tunnel linings optimization designs.
As the technical cooperation and communication are frequent in the world, models for tunnel lining design are becoming unanimous, but the researches for appropriate computational models have never been stopped and more and more of them have been brought out. Accoring to tunnel construction steps, contact surface between segments and soil and stress releasing, 2D-FEM is put forward to simulate shield tunnel construction.The conclusion and methods can provide valuable preference for tunnel linings optimization designs.
2004, 34(4): 61-65.
doi: 10.13204/j.gyjz200404018
Abstract:
A grey relative degree decision making model based on information entropy and AHP is established, and a conception of combinatorial weight is put forward after analyzing problems in projects decision making of geotechnical engineering. The model, proved by real projects, considers influence of subjective factors and importance of information of projects index system, which provides a new thinking to select geotechnical engineering projects more scientifically and exactly.
A grey relative degree decision making model based on information entropy and AHP is established, and a conception of combinatorial weight is put forward after analyzing problems in projects decision making of geotechnical engineering. The model, proved by real projects, considers influence of subjective factors and importance of information of projects index system, which provides a new thinking to select geotechnical engineering projects more scientifically and exactly.
2004, 34(4): 66-68,65.
doi: 10.13204/j.gyjz200404019
Abstract:
Concrete structures located near sea may exhibit bad durability, due to exposing to unfavorable atmosphere, such as high content of chloride ion and fluctuating humidity, for a long time. Thus heavier steel corrosion with cracking and spalling may occur in the design working life, which makes the serviceability and safety worse. Investigations and test to realistic concrete structures have been made, and the damage mechanism and its influencing coefficients of concrete structures under unfavorable atmosphere have been analyzed.The rehabilitation methodology and its effects on the durability of concrete structures have been discussed.Suggestions on rehabilitation and protection of concrete structures exposed to chloride ion and fluctuating humidity are made.
Concrete structures located near sea may exhibit bad durability, due to exposing to unfavorable atmosphere, such as high content of chloride ion and fluctuating humidity, for a long time. Thus heavier steel corrosion with cracking and spalling may occur in the design working life, which makes the serviceability and safety worse. Investigations and test to realistic concrete structures have been made, and the damage mechanism and its influencing coefficients of concrete structures under unfavorable atmosphere have been analyzed.The rehabilitation methodology and its effects on the durability of concrete structures have been discussed.Suggestions on rehabilitation and protection of concrete structures exposed to chloride ion and fluctuating humidity are made.
2004, 34(4): 69-72.
doi: 10.13204/j.gyjz200404020
Abstract:
A predicting model on carbonation depth considering the effects of stress is built based on the seven fast-carbonation experiment modules. Then, an analysis from theory is given to the prestressed concrete structure in cracked state. According to the theory of structure reliability, an analysis method of durability of PC structure in carbonation is developed.
A predicting model on carbonation depth considering the effects of stress is built based on the seven fast-carbonation experiment modules. Then, an analysis from theory is given to the prestressed concrete structure in cracked state. According to the theory of structure reliability, an analysis method of durability of PC structure in carbonation is developed.
2004, 34(4): 73-75.
doi: 10.13204/j.gyjz200404021
Abstract:
Energy-saving for buildings is an important part of carrying out the sustainable development strategy of our country.At the moment the shortage of the resources is becoming more serious, the structures energy consumption is tremendous; and the energy-saving for buildings is at the primary stage as compared with the developed countries. Some suggestions on energy-saving for buildings are proposed. It has very powerful value in carrying forward and perfecting energy-saving for buildings.
Energy-saving for buildings is an important part of carrying out the sustainable development strategy of our country.At the moment the shortage of the resources is becoming more serious, the structures energy consumption is tremendous; and the energy-saving for buildings is at the primary stage as compared with the developed countries. Some suggestions on energy-saving for buildings are proposed. It has very powerful value in carrying forward and perfecting energy-saving for buildings.
2004, 34(4): 76-78.
doi: 10.13204/j.gyjz200404022
Abstract:
The spatially latticed circular arch structure with triangular section is a new structural system and has lots of advantages such as architecturally attractive shape, rational loading performance, economy and practicality.Stability calculation is the key problem of the arch structure design.By means of the finite element program ANSYS, the geometrical non-linear analysis of this circular arch was conducted under the unitformly distributed load along whole span.According to the general load-deformation response curves, the basic law of the stability of the spatial lattice arch structure has been obtained.The matching formulae were given by the value regression method, which can be used to calculate the in-plane global stability critical load of these structures.
The spatially latticed circular arch structure with triangular section is a new structural system and has lots of advantages such as architecturally attractive shape, rational loading performance, economy and practicality.Stability calculation is the key problem of the arch structure design.By means of the finite element program ANSYS, the geometrical non-linear analysis of this circular arch was conducted under the unitformly distributed load along whole span.According to the general load-deformation response curves, the basic law of the stability of the spatial lattice arch structure has been obtained.The matching formulae were given by the value regression method, which can be used to calculate the in-plane global stability critical load of these structures.
2004, 34(4): 79-81.
doi: 10.13204/j.gyjz200404023
Abstract:
Employing the slope deflection equation and considering stiffness modified by the axial force to vertical columns, the simple method of calculation of the deflection of portal steel frame at collapse is presented. Besides, the calculation method of effect of deflection on the collapse load is also presented. To make use of this method may calculate effect of deflection at collapse on the collapse load.
Employing the slope deflection equation and considering stiffness modified by the axial force to vertical columns, the simple method of calculation of the deflection of portal steel frame at collapse is presented. Besides, the calculation method of effect of deflection on the collapse load is also presented. To make use of this method may calculate effect of deflection at collapse on the collapse load.
2004, 34(4): 82-83,91.
doi: 10.13204/j.gyjz200404024
Abstract:
The optimum design of prestress of a tensioned integral structure is studied. The states of self-stress are obtained by employing the method of singular value decomposition. The combination coefficients of self-stress states and cross-sectional areas of members are taken as the design variables. The mathematical model of optimization design is established and a sequential two-step algorithm is presented. Numerical example is provided to illustrate feasibility and correctness of the method.
The optimum design of prestress of a tensioned integral structure is studied. The states of self-stress are obtained by employing the method of singular value decomposition. The combination coefficients of self-stress states and cross-sectional areas of members are taken as the design variables. The mathematical model of optimization design is established and a sequential two-step algorithm is presented. Numerical example is provided to illustrate feasibility and correctness of the method.
2004, 34(4): 84-85,81.
doi: 10.13204/j.gyjz200404025
Abstract:
A new type of bolt connectioninsulating bolt, which was developed by this research, can avoid some disadvantages such as cold bridge, corrosion and electric conduction which usually occur in installations of outer steel structures. The conception of insulating bolt was introduced and strength tests on insulating bolts were carried out through comparing four different insulation materials. The results of tests confirmed that the insulating bolts can achieve the design objectives and satisfy the strength requirements of steel structures.
A new type of bolt connectioninsulating bolt, which was developed by this research, can avoid some disadvantages such as cold bridge, corrosion and electric conduction which usually occur in installations of outer steel structures. The conception of insulating bolt was introduced and strength tests on insulating bolts were carried out through comparing four different insulation materials. The results of tests confirmed that the insulating bolts can achieve the design objectives and satisfy the strength requirements of steel structures.
2004, 34(4): 86-88,45.
doi: 10.13204/j.gyjz200404026
Abstract:
A shear type model is used as the dynamic analytical model for the whole structure and a semidegrading tetralinear model with a descending branch is selected as restoring force model for the interstory columns. The parameter of the restoring force model for the interstory force model is computed by the nonlinear relation of M-, and the corresponding program IDAFF is developed. By analyzing the difference of the result between IDAFF and TAT, it can be concluded that:the result on rotation of inter-story displacement complied with the codes is on the high side under a minor earthquake and is possible on the low side under a major earthquake.
A shear type model is used as the dynamic analytical model for the whole structure and a semidegrading tetralinear model with a descending branch is selected as restoring force model for the interstory columns. The parameter of the restoring force model for the interstory force model is computed by the nonlinear relation of M-, and the corresponding program IDAFF is developed. By analyzing the difference of the result between IDAFF and TAT, it can be concluded that:the result on rotation of inter-story displacement complied with the codes is on the high side under a minor earthquake and is possible on the low side under a major earthquake.
2004, 34(4): 89-91.
doi: 10.13204/j.gyjz200404027
Abstract:
The deficiency in testing principle and measuring technique as well as the limitation for application of ASTM C1202 are reviewed and discussed.
The deficiency in testing principle and measuring technique as well as the limitation for application of ASTM C1202 are reviewed and discussed.
2004, 34(4): 92-93.
doi: 10.13204/j.gyjz200404028
Abstract:
A new and full understanding, penetration and pursuit of landscape conception are explored according to modern planning of residential area. Landscape design is also analyzed by combining actual cases with an emphasis on streamline space of road, landscape of central green belt and in-and-out door vision.
A new and full understanding, penetration and pursuit of landscape conception are explored according to modern planning of residential area. Landscape design is also analyzed by combining actual cases with an emphasis on streamline space of road, landscape of central green belt and in-and-out door vision.
2004, 34(4): 94-95,75.
doi: 10.13204/j.gyjz200404029
Abstract:
Through an analysis of friction coefficient and two key factors of friction in prestressed concrete structure, the shortage of current calculation method is pointed out and corresponded improving suggestion is put forward as well.
Through an analysis of friction coefficient and two key factors of friction in prestressed concrete structure, the shortage of current calculation method is pointed out and corresponded improving suggestion is put forward as well.
