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2006 Vol. 36, No. 12
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2006, 36(12): 1-4,33.
doi: 10.13204/j.gyjz200612001
Abstract:
The limestone filler cement mortars with different mixing proportions were immersed into different sulfate solutions for one year,and their visual appearances, strength and mineral composition were measured at intervals.The results show that the resistance of mortar to thaumasite form of sulfate attack(TSA) increases with the reduction of water-cement ratio.The relative resistance to TSA of the cements is outlined below,from best to worst: sulphoaluminate cement,sulfate resisting Portland cement,ordinary Portland cement.The resistance to TSA of mortar is remarkably improved by the addition of silica fume or ground granulated blastfurnace slag(ggbs),and the better the resistance to TSA,the more the addition of ggbs is.Magnesium salts reinforce the thaumasite formation and the thaumasite form of sulfate attack in the cement mortars.It reveals that TSA may also occur to structures at temperatures of higher than 15℃.The influence of temperature on the whole resistance to sulfate attack of mortar is related to the material composition.
The limestone filler cement mortars with different mixing proportions were immersed into different sulfate solutions for one year,and their visual appearances, strength and mineral composition were measured at intervals.The results show that the resistance of mortar to thaumasite form of sulfate attack(TSA) increases with the reduction of water-cement ratio.The relative resistance to TSA of the cements is outlined below,from best to worst: sulphoaluminate cement,sulfate resisting Portland cement,ordinary Portland cement.The resistance to TSA of mortar is remarkably improved by the addition of silica fume or ground granulated blastfurnace slag(ggbs),and the better the resistance to TSA,the more the addition of ggbs is.Magnesium salts reinforce the thaumasite formation and the thaumasite form of sulfate attack in the cement mortars.It reveals that TSA may also occur to structures at temperatures of higher than 15℃.The influence of temperature on the whole resistance to sulfate attack of mortar is related to the material composition.
2006, 36(12): 5-8.
doi: 10.13204/j.gyjz200612002
Abstract:
In large-scale engineerings the corrosion of materials has significant influence on the durability of structures,especially underground structures,such as subway tunnel.Therefore,it is important to understand and analyze correctly the reason and mechanism of material corrision.Aimed at the corrosion of the stray current in metro,laboratory experiments of corrosion effects of metro stray current on steel fiber reinforced concrete are carried out.Based on the equivalence of the failure mechanisms of steel fiber concrete and reinforced concrete,a theoretical model is proposed to predict the failure of steel fiber reinforced concrete structure under the action of stray current.
In large-scale engineerings the corrosion of materials has significant influence on the durability of structures,especially underground structures,such as subway tunnel.Therefore,it is important to understand and analyze correctly the reason and mechanism of material corrision.Aimed at the corrosion of the stray current in metro,laboratory experiments of corrosion effects of metro stray current on steel fiber reinforced concrete are carried out.Based on the equivalence of the failure mechanisms of steel fiber concrete and reinforced concrete,a theoretical model is proposed to predict the failure of steel fiber reinforced concrete structure under the action of stray current.
2006, 36(12): 9-11,8.
doi: 10.13204/j.gyjz200612003
Abstract:
An electrical conductivity method is employed to estimate the temporal dependence of the chloride permeability of blended concretes(fly ash,ground granulated blast-furnace slag,silica fume).The results show that a power law function is suited to describe the relationship between conductance and time after 180 days' curing,and the function parameters are mathematically fitted.Mineral admixtures can remarkably improve the concrete electrical resistance.The water to binder ratio(W/B) has also great influence on the concrete resistance to chloride penetration,the higher the W/B,the lower permeability of the concrete to chloride.
An electrical conductivity method is employed to estimate the temporal dependence of the chloride permeability of blended concretes(fly ash,ground granulated blast-furnace slag,silica fume).The results show that a power law function is suited to describe the relationship between conductance and time after 180 days' curing,and the function parameters are mathematically fitted.Mineral admixtures can remarkably improve the concrete electrical resistance.The water to binder ratio(W/B) has also great influence on the concrete resistance to chloride penetration,the higher the W/B,the lower permeability of the concrete to chloride.
2006, 36(12): 12-15.
doi: 10.13204/j.gyjz200612004
Abstract:
The experiments on corrosion of concrete were carried out under double action of sulfate and circulation of frost and thaw.The tests show that sulfate erosion and frost and thaw have evident influence on mechanical properties of concrete.Erosion rate is accelerated under double action of sulfate erosion and circulation of frost and thaw.At the same time,the erosion mechanism of concrete is also analyzed.
The experiments on corrosion of concrete were carried out under double action of sulfate and circulation of frost and thaw.The tests show that sulfate erosion and frost and thaw have evident influence on mechanical properties of concrete.Erosion rate is accelerated under double action of sulfate erosion and circulation of frost and thaw.At the same time,the erosion mechanism of concrete is also analyzed.
2006, 36(12): 16-19,23.
doi: 10.13204/j.gyjz200612005
Abstract:
The research shows that the rate of chloride transport in concrete under wet and dry cycles is rapider than that in saturated concrete.This means the mechanism of chloride transport process is different in different environments.The mechanism of chloride transport process under wet and dry cycles is studied and a chloride transport model is developed which provides a reference for predicting accurately the service life of an actual concrete structure.
The research shows that the rate of chloride transport in concrete under wet and dry cycles is rapider than that in saturated concrete.This means the mechanism of chloride transport process is different in different environments.The mechanism of chloride transport process under wet and dry cycles is studied and a chloride transport model is developed which provides a reference for predicting accurately the service life of an actual concrete structure.
2006, 36(12): 20-23.
doi: 10.13204/j.gyjz200612006
Abstract:
It is introduced that investigation and evaluation of durability of concrete supports of pipelines nearly with 30 years' service in a chemical plant.It could be used as reference for design,construction,maintenance and management of similar structures.
It is introduced that investigation and evaluation of durability of concrete supports of pipelines nearly with 30 years' service in a chemical plant.It could be used as reference for design,construction,maintenance and management of similar structures.
2006, 36(12): 24-27.
doi: 10.13204/j.gyjz200612007
Abstract:
It is tried to discuss the basic principles of design of a woolen mill through the architectural design of the woolen mill(phase-Ⅰ) in Fuxin Industry Park,Heyuan,and it is also pointed out that the arrangement mode based on the storage and logistics Furthermore,the principles and methods of dealing with industry architectures form and environment are also mentioned,which may be a reference for design of similar industry projects.
It is tried to discuss the basic principles of design of a woolen mill through the architectural design of the woolen mill(phase-Ⅰ) in Fuxin Industry Park,Heyuan,and it is also pointed out that the arrangement mode based on the storage and logistics Furthermore,the principles and methods of dealing with industry architectures form and environment are also mentioned,which may be a reference for design of similar industry projects.
2006, 36(12): 28-30,49.
doi: 10.13204/j.gyjz200612008
Abstract:
It is explored the principle of planning and designing the industrial factories in special topographical conditions,by a brief introduction to the design of the new factory for Guangdong Lianri(Qingyuan) Textile Clothing Co.,Ltd.
It is explored the principle of planning and designing the industrial factories in special topographical conditions,by a brief introduction to the design of the new factory for Guangdong Lianri(Qingyuan) Textile Clothing Co.,Ltd.
2006, 36(12): 31-33.
doi: 10.13204/j.gyjz200612009
Abstract:
A nonlinear FEM analysis model is set up based on the finite element analysis softwareANSYS.The staggered shear wall structure and the coupled shear wall structure are analyzed with this model.As compared with traditional shear wall structures,the staggered shear wall structure has many advantages,such as providing bigger space and lateral stiffness,reducing dead weigh and seismic force,and saving constructional materials.Therefore,this structural system has good economic benefits and wide applications.
A nonlinear FEM analysis model is set up based on the finite element analysis softwareANSYS.The staggered shear wall structure and the coupled shear wall structure are analyzed with this model.As compared with traditional shear wall structures,the staggered shear wall structure has many advantages,such as providing bigger space and lateral stiffness,reducing dead weigh and seismic force,and saving constructional materials.Therefore,this structural system has good economic benefits and wide applications.
2006, 36(12): 34-36,64.
doi: 10.13204/j.gyjz200612010
Abstract:
With the increase in use of mega-frame structures,the main frame beam-column reasonable arrangement becomes the key problem of a design.The results of a 24-story mega-frame structure with 4-span was calculated by the universal finite element program SAP 2000.At the condition of equal total section area of main frame beam-column,changing the size and number of main frame beam-column,the different structural free vibration periods,structural sways and structural moments were compared,the influence of main frame beam-column arrangement on behaviors of mega frame structures were discussed,and some reasonable suggestions were put forward to guide engineering practice.
With the increase in use of mega-frame structures,the main frame beam-column reasonable arrangement becomes the key problem of a design.The results of a 24-story mega-frame structure with 4-span was calculated by the universal finite element program SAP 2000.At the condition of equal total section area of main frame beam-column,changing the size and number of main frame beam-column,the different structural free vibration periods,structural sways and structural moments were compared,the influence of main frame beam-column arrangement on behaviors of mega frame structures were discussed,and some reasonable suggestions were put forward to guide engineering practice.
2006, 36(12): 37-40.
doi: 10.13204/j.gyjz200612011
Abstract:
The pump house is an important infrastructure for thermal power plants.It directly affects the reliability of power system.Based on the structural characteristics,site inspections,structural analysis and remaining life estimation of the floodable pump houses,the structural reliability is assessed,and the strategies of strengthening and rehabilitation of these pump houses are suggested.
The pump house is an important infrastructure for thermal power plants.It directly affects the reliability of power system.Based on the structural characteristics,site inspections,structural analysis and remaining life estimation of the floodable pump houses,the structural reliability is assessed,and the strategies of strengthening and rehabilitation of these pump houses are suggested.
2006, 36(12): 41-43.
doi: 10.13204/j.gyjz200612012
Abstract:
It is one of the defects that cracks occur in the bottom slab of an extra-long prestressed concrete continuous rigid frame bridge.There are many influence factors.By way of example of a bridge,the causes of cracks are analyzed by means of finite element method and in the light of construction conditions.And some measures to treat the existing cracks are made according to the features of the extra-long prestressed concrete continuous rigid frame bridge,which are expected to serve as reference to the practical application.
It is one of the defects that cracks occur in the bottom slab of an extra-long prestressed concrete continuous rigid frame bridge.There are many influence factors.By way of example of a bridge,the causes of cracks are analyzed by means of finite element method and in the light of construction conditions.And some measures to treat the existing cracks are made according to the features of the extra-long prestressed concrete continuous rigid frame bridge,which are expected to serve as reference to the practical application.
2006, 36(12): 44-49.
doi: 10.13204/j.gyjz200612013
Abstract:
In a 170.10m high and 37-storey super-tall building with 3-storey podium,excavation depth of 22.4～28.4m and an area of 5 151m2 in Shanghai,based on the theoretical concept and experience,it is analyzed that a great deal of monitoring results for horizontal displacements,bottom heave,differential displacements between diaphrgam wall and adjacent mid-post pile and between mid-post piles,bracing axial force and stresses in slab of floor for special deep excavation,and significant characteristics of stress and displacement for up-down construction method differing with normal construction method are also been obtained.Some suggestions on improving the design of up-down construction method for deep excavation engineering are presented,which may be an impartant reference for other similar projects.
In a 170.10m high and 37-storey super-tall building with 3-storey podium,excavation depth of 22.4～28.4m and an area of 5 151m2 in Shanghai,based on the theoretical concept and experience,it is analyzed that a great deal of monitoring results for horizontal displacements,bottom heave,differential displacements between diaphrgam wall and adjacent mid-post pile and between mid-post piles,bracing axial force and stresses in slab of floor for special deep excavation,and significant characteristics of stress and displacement for up-down construction method differing with normal construction method are also been obtained.Some suggestions on improving the design of up-down construction method for deep excavation engineering are presented,which may be an impartant reference for other similar projects.
2006, 36(12): 50-51,59.
doi: 10.13204/j.gyjz200612014
Abstract:
It is determined that coefficient of static earth pressure is influenced by the increase of over consolidation ratio(OCR).When over consolidation ratio exceeds 2.5,the relationship of coefficient of static earth pressure and over consolidation ratio is determined to be nonlinear,and expressed with an exponential function.Therefore,in order to avoid an uneconomical design of a retaining structure,over consolidation ratio should be considered to calculate earth pressure at a retaining structure by using the elastic and plasticity method.
It is determined that coefficient of static earth pressure is influenced by the increase of over consolidation ratio(OCR).When over consolidation ratio exceeds 2.5,the relationship of coefficient of static earth pressure and over consolidation ratio is determined to be nonlinear,and expressed with an exponential function.Therefore,in order to avoid an uneconomical design of a retaining structure,over consolidation ratio should be considered to calculate earth pressure at a retaining structure by using the elastic and plasticity method.
2006, 36(12): 52-55.
doi: 10.13204/j.gyjz200612015
Abstract:
The boundary element method for the analysis of layered soil is presented using the fundamental solutions of three-dimensional multilayered solids.The generalized Kelvin basic solution and the boundary element method coupling,the boundary integral equation is established for the layered soil boundary value problem,which does not include interface integral.The singular integral calculus appearing in the kernel function is made solution.It is shown that the present method is efficient for the stress and displacement in layered soil.
The boundary element method for the analysis of layered soil is presented using the fundamental solutions of three-dimensional multilayered solids.The generalized Kelvin basic solution and the boundary element method coupling,the boundary integral equation is established for the layered soil boundary value problem,which does not include interface integral.The singular integral calculus appearing in the kernel function is made solution.It is shown that the present method is efficient for the stress and displacement in layered soil.
2006, 36(12): 56-59.
doi: 10.13204/j.gyjz200612016
Abstract:
Based on the stress-strain relationship,the non-linear relationship between the shaft resistance and pile relative displacement of rammed soil-cement pile loading tests,through numerical analysis method,bearing mechanism and critical length of rammed soil-cement pile are studied.Influence factors of critical length,such as rammed soil-cement limit strength q-u,shaft resistance -u and diameter d,are thoroughly analyzed.Proposed critical length of rammed soil-cement pile is given.
Based on the stress-strain relationship,the non-linear relationship between the shaft resistance and pile relative displacement of rammed soil-cement pile loading tests,through numerical analysis method,bearing mechanism and critical length of rammed soil-cement pile are studied.Influence factors of critical length,such as rammed soil-cement limit strength q-u,shaft resistance -u and diameter d,are thoroughly analyzed.Proposed critical length of rammed soil-cement pile is given.
2006, 36(12): 60-64.
doi: 10.13204/j.gyjz200612017
Abstract:
State-of-the-art of studies on fire resistance of prestressed concrete structures at home and abroad is summarized and analyzed systematically.The fire resistance of high-strength wires,strands and new type fiber reinforced plastic(FRP) tendons under and after high temperature are studied and the corresponding analytical models are presented.The fire resistance of prestressed concrete beams and slabs as well as prestressed concrete frame is investigated.At last,the future research directions upon the fire resistance of prestressed concrete structures are discussed.
State-of-the-art of studies on fire resistance of prestressed concrete structures at home and abroad is summarized and analyzed systematically.The fire resistance of high-strength wires,strands and new type fiber reinforced plastic(FRP) tendons under and after high temperature are studied and the corresponding analytical models are presented.The fire resistance of prestressed concrete beams and slabs as well as prestressed concrete frame is investigated.At last,the future research directions upon the fire resistance of prestressed concrete structures are discussed.
2006, 36(12): 65-68.
doi: 10.13204/j.gyjz200612018
Abstract:
The study and application on anchorages of prestressed FRP tendons are introduced.It is mainly focused on the demands for prestressed FRP tendon-anchor systems and the achievements of anchorages.Finally advices for research and application of anchorages of prestressed FRP tendons in China are provided.
The study and application on anchorages of prestressed FRP tendons are introduced.It is mainly focused on the demands for prestressed FRP tendon-anchor systems and the achievements of anchorages.Finally advices for research and application of anchorages of prestressed FRP tendons in China are provided.
2006, 36(12): 69-72,27.
doi: 10.13204/j.gyjz200612019
Abstract:
It has been done that axial compressive experiments on 11 long hollow concrete-filled steel tube(H-CFST) specimens,and analysed the influence of hollow ratio,slenderness ratio and sectional form on bearing capacity of long H-CFST,studied the deformed states of specimens.The results show that the deformed states of long H-CFST specimens are similar to those of steel tubes.The experimental data on other researchers are collected and the formula put forward by the authors is compared with the formula of Technical Code on the Centrifugal Concrete Filled Thin-Wall Steel Tubular Structures,and the results are acceptable.
It has been done that axial compressive experiments on 11 long hollow concrete-filled steel tube(H-CFST) specimens,and analysed the influence of hollow ratio,slenderness ratio and sectional form on bearing capacity of long H-CFST,studied the deformed states of specimens.The results show that the deformed states of long H-CFST specimens are similar to those of steel tubes.The experimental data on other researchers are collected and the formula put forward by the authors is compared with the formula of Technical Code on the Centrifugal Concrete Filled Thin-Wall Steel Tubular Structures,and the results are acceptable.
2006, 36(12): 73-75.
doi: 10.13204/j.gyjz200612020
Abstract:
Light-weight steel multi-storey structures are widely used and developing rapidly all over the world.At the present time,much work on the study of the static behavior has been done,but the analysis of the dynamic properties is rare.Taking a specific engineering as an example,the dynamic properties are analyzed by the finite element software ANSYS,including modal analysis,spectrum analysis,elastoplastic time-history analysis,whose results are compared with those of PKPM.The result shows,the whiplash effect exists,but in comparison,the ground floor is affected more severely in earthquake.
Light-weight steel multi-storey structures are widely used and developing rapidly all over the world.At the present time,much work on the study of the static behavior has been done,but the analysis of the dynamic properties is rare.Taking a specific engineering as an example,the dynamic properties are analyzed by the finite element software ANSYS,including modal analysis,spectrum analysis,elastoplastic time-history analysis,whose results are compared with those of PKPM.The result shows,the whiplash effect exists,but in comparison,the ground floor is affected more severely in earthquake.
2006, 36(12): 76-79,82.
doi: 10.13204/j.gyjz200612021
Abstract:
Based on the theoretics and experiment results,shear strength calculation formula of concrete-filled steel tube beam-column joints of tall buildings is presented.In the formula,not only the real forced state of joints is considered,but also the combanistion effect of the steel tube and the concrete.Finally,applicable range of the formula is presented for designers to refer.
Based on the theoretics and experiment results,shear strength calculation formula of concrete-filled steel tube beam-column joints of tall buildings is presented.In the formula,not only the real forced state of joints is considered,but also the combanistion effect of the steel tube and the concrete.Finally,applicable range of the formula is presented for designers to refer.
2006, 36(12): 80-82.
doi: 10.13204/j.gyjz200612022
Abstract:
It is presented experimental study on shear behavior of diaphragm assembly using V-840 profiled steel sheet.It is also compared the different effect of the stressed diaphragm action with purlins and without purlins and the experimental result indicates that the edge member and sufficient fastenings are vital to the stressed diaphragm action to work.It is acceptable to use the BS code of stressed diaphragm to design as compared with experimental results.
It is presented experimental study on shear behavior of diaphragm assembly using V-840 profiled steel sheet.It is also compared the different effect of the stressed diaphragm action with purlins and without purlins and the experimental result indicates that the edge member and sufficient fastenings are vital to the stressed diaphragm action to work.It is acceptable to use the BS code of stressed diaphragm to design as compared with experimental results.
2006, 36(12): 83-85,104.
doi: 10.13204/j.gyjz200612023
Abstract:
The tube-gusset joint is widely applied in tall steel tubular tower,however there has been few study on this kind of joint.Combining a steel tubular tower from practical engineering,typical tube-gusset joints were analyzed and whole course analysis based on elasto plastic FEM calculation is conducted.Comparing FEM results with experimental results from full scale model,some conclusions which will be helpful to theoretical study and engineering design of the kind of joints are presented.
The tube-gusset joint is widely applied in tall steel tubular tower,however there has been few study on this kind of joint.Combining a steel tubular tower from practical engineering,typical tube-gusset joints were analyzed and whole course analysis based on elasto plastic FEM calculation is conducted.Comparing FEM results with experimental results from full scale model,some conclusions which will be helpful to theoretical study and engineering design of the kind of joints are presented.
2006, 36(12): 86-89,95.
doi: 10.13204/j.gyjz200612024
Abstract:
The technology of strengthening reinforced concrete beams with prestressed CFRP sheets has become a hot spot of the research on adhesive strengthenings in recent years due to high efficient use of CFRP sheets' strength,and the change in the beams' properties under normal use.It was compared and analyzed the differences among the RC beam strengthened with prestressed CFRP sheets,the one strengthened with nonprestressed CFRP sheets as well as that without strengthening through the experimental study on three T-RC beams strengthened with prestressed CFRP sheets.The advantages of strengthening by CFRP sheets were further verified by the test results.The study may provide a reference for similar researches in the future.
The technology of strengthening reinforced concrete beams with prestressed CFRP sheets has become a hot spot of the research on adhesive strengthenings in recent years due to high efficient use of CFRP sheets' strength,and the change in the beams' properties under normal use.It was compared and analyzed the differences among the RC beam strengthened with prestressed CFRP sheets,the one strengthened with nonprestressed CFRP sheets as well as that without strengthening through the experimental study on three T-RC beams strengthened with prestressed CFRP sheets.The advantages of strengthening by CFRP sheets were further verified by the test results.The study may provide a reference for similar researches in the future.
2006, 36(12): 90-92,99.
doi: 10.13204/j.gyjz200612025
Abstract:
Combining the basic idea of performance-based design and strengthening design with carbon fiber reinforced polymer(CFRP),the theory of performance-based rehabilitation design with CFRP is presented in this paper.According to the theory,performance objectives and evaluation criterion of rehabilitation design are introduced.In addition,available stress of CFRP is discussed under different performance criterion.On the basis of the theory,a case is employed to analyzed the variation of the quantity of CFRP used under different performance objectives, which indicates that the quantity of CFRP varies very differently.In a word,performance-based rehabilitation design theory of CFRP is an economic,efficient and feasible design method.
Combining the basic idea of performance-based design and strengthening design with carbon fiber reinforced polymer(CFRP),the theory of performance-based rehabilitation design with CFRP is presented in this paper.According to the theory,performance objectives and evaluation criterion of rehabilitation design are introduced.In addition,available stress of CFRP is discussed under different performance criterion.On the basis of the theory,a case is employed to analyzed the variation of the quantity of CFRP used under different performance objectives, which indicates that the quantity of CFRP varies very differently.In a word,performance-based rehabilitation design theory of CFRP is an economic,efficient and feasible design method.
2006, 36(12): 93-95.
doi: 10.13204/j.gyjz200612026
Abstract:
The imitation test cubes were made in the water to test the mechanical properties of non-dispersing concrete with anti-dispersing agent,and the capability of bonding the non-dispersing concrete and the original concrete bottom plates.Using submerged constructing method,the non-dispersing concrete was successfully applied to reinforcing the pool's bottom plates by fixing head forms.It provided a new way of submerged reinforcing projects.
The imitation test cubes were made in the water to test the mechanical properties of non-dispersing concrete with anti-dispersing agent,and the capability of bonding the non-dispersing concrete and the original concrete bottom plates.Using submerged constructing method,the non-dispersing concrete was successfully applied to reinforcing the pool's bottom plates by fixing head forms.It provided a new way of submerged reinforcing projects.
2006, 36(12): 96-99.
doi: 10.13204/j.gyjz200612027
Abstract:
In the development of Chinese architecture,it has been influenced by foreign architectures in ancient and modern times in different ways.It is analysed the different expressions and characteristics of the influences of foreign architectures in different historical stages,and then it is concluded what we should do with the foreign architecture:open,study and create.
In the development of Chinese architecture,it has been influenced by foreign architectures in ancient and modern times in different ways.It is analysed the different expressions and characteristics of the influences of foreign architectures in different historical stages,and then it is concluded what we should do with the foreign architecture:open,study and create.
2006, 36(12): 100-104.
doi: 10.13204/j.gyjz200612028
Abstract:
By unscrambling modern architect masters Louis Isadore.Kahn and Swiss architect Mario Botta's architecture thinking and works,it is analyzed that at the effect of Louis IKahn,Mario Botta made his own way in architecture,and it is also pointed out that inheriting and innovating in architecture are the two very important aspects in modern pluralistic cultural tidal waves,and their enlightening and help to the development of China's architecture are finally explored.
By unscrambling modern architect masters Louis Isadore.Kahn and Swiss architect Mario Botta's architecture thinking and works,it is analyzed that at the effect of Louis IKahn,Mario Botta made his own way in architecture,and it is also pointed out that inheriting and innovating in architecture are the two very important aspects in modern pluralistic cultural tidal waves,and their enlightening and help to the development of China's architecture are finally explored.
