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2004 Vol. 34, No. 1
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2004, 34(1): 1-5.
doi: 10.13204/j.gyjz200401001
Abstract:
Tests of six circular concrete-filled steel tubes subjected to pure bending were carried out.The difference between the initial flexural stiffness and the serviceability-level flexural stiffness of the experimental results was compared and discussed.The experimental results were compared with other relative research results and design codes both at home and abroad.The calculation method of the flexural stiffness of circular concrete-filled steel tube was discussed.
Tests of six circular concrete-filled steel tubes subjected to pure bending were carried out.The difference between the initial flexural stiffness and the serviceability-level flexural stiffness of the experimental results was compared and discussed.The experimental results were compared with other relative research results and design codes both at home and abroad.The calculation method of the flexural stiffness of circular concrete-filled steel tube was discussed.
2004, 34(1): 6-9,5.
doi: 10.13204/j.gyjz200401002
Abstract:
A total of five specimens were tested under pure bending to investigate the behavior of concrete-filled double-skin steel tubular (CFDST)beams.The specimens were fabricated with square hollow section (SHS) as outer skin and circular hollow section(CHS)as inner skin.The parameter varied in the tests was hollow section ratio.Utilizing the stress-strain relations of steel and concrete presented in the literature for concrete-filled square steel tubes, a numerical method is applied to the analysis of load-deformation curves of the double-skin composite members subjected to pure bending.The calculated results agree well with those of the tests.A simplified model is developed for calculating the bearing capacity and rigidity of the CFDST beams, which may be a reference for engineering practice.
A total of five specimens were tested under pure bending to investigate the behavior of concrete-filled double-skin steel tubular (CFDST)beams.The specimens were fabricated with square hollow section (SHS) as outer skin and circular hollow section(CHS)as inner skin.The parameter varied in the tests was hollow section ratio.Utilizing the stress-strain relations of steel and concrete presented in the literature for concrete-filled square steel tubes, a numerical method is applied to the analysis of load-deformation curves of the double-skin composite members subjected to pure bending.The calculated results agree well with those of the tests.A simplified model is developed for calculating the bearing capacity and rigidity of the CFDST beams, which may be a reference for engineering practice.
2004, 34(1): 10-13,89.
doi: 10.13204/j.gyjz200401003
Abstract:
Local compression is a normal case in civil engineering.In order to have a further research on the local compression behaviors of concrete-filled steel tubular members with square sections, 28 axially loaded members under local compression were studied.Local compression tests of plain concrete and bearing strength tests of CFST were done simultaneously as a comparison, push-out tests were also carried out for bond strength.Based on the test results, the main factors were studied, and a method for bearing strength calculation was initially proposed.
Local compression is a normal case in civil engineering.In order to have a further research on the local compression behaviors of concrete-filled steel tubular members with square sections, 28 axially loaded members under local compression were studied.Local compression tests of plain concrete and bearing strength tests of CFST were done simultaneously as a comparison, push-out tests were also carried out for bond strength.Based on the test results, the main factors were studied, and a method for bearing strength calculation was initially proposed.
2004, 34(1): 14-17.
doi: 10.13204/j.gyjz200401004
Abstract:
The calculating results illustrate that the load acting on a concrete-filled steel tubular column has a great influence on the fire resistance time and fire protection thickness.Based on the numerical results and the prophase achievements of our research group, formulae which consider the influence of load ratio under fire, for the calculation of fire spray materials thickness of the composite columns under ISO-834 or GB/T 9978-1999 Standard Fire Curve are presented in this paper.Generally, the calculated results agree basically with the numerical and experimental results.
The calculating results illustrate that the load acting on a concrete-filled steel tubular column has a great influence on the fire resistance time and fire protection thickness.Based on the numerical results and the prophase achievements of our research group, formulae which consider the influence of load ratio under fire, for the calculation of fire spray materials thickness of the composite columns under ISO-834 or GB/T 9978-1999 Standard Fire Curve are presented in this paper.Generally, the calculated results agree basically with the numerical and experimental results.
2004, 34(1): 18-20.
doi: 10.13204/j.gyjz200401005
Abstract:
On the basis of deciding the stress-strain relations of steel, bars and core concrete of bar-reinforced concrete filled square steel tubes, a theoretical model for the analysis of fire resistance has been put forward.The model has been validated by testing results.There is a good agreement between the two.The method introduced in this paper may be a reference for fireproof design of this sort of column.
On the basis of deciding the stress-strain relations of steel, bars and core concrete of bar-reinforced concrete filled square steel tubes, a theoretical model for the analysis of fire resistance has been put forward.The model has been validated by testing results.There is a good agreement between the two.The method introduced in this paper may be a reference for fireproof design of this sort of column.
2004, 34(1): 21-25,28.
doi: 10.13204/j.gyjz200401006
Abstract:
Tests were performed of 4 concrete-filled steel tubular stubs and 4 flexural members after ISO-834 standard fire.A numerical method was developed to predict the changing of axial rigidity and flexural rigidity of concrete-filled steel tubular members after fire, with predicted results in a good agreement with test results.A practical method is suggested for calculating the rigidity of CFST axial and flexural members after fire based on the theoretical and experimental results.
Tests were performed of 4 concrete-filled steel tubular stubs and 4 flexural members after ISO-834 standard fire.A numerical method was developed to predict the changing of axial rigidity and flexural rigidity of concrete-filled steel tubular members after fire, with predicted results in a good agreement with test results.A practical method is suggested for calculating the rigidity of CFST axial and flexural members after fire based on the theoretical and experimental results.
2004, 34(1): 26-28.
doi: 10.13204/j.gyjz200401007
Abstract:
According to the sustainable development principle, this paper puts forward a new thinking, which includes using concaves to store flood, constructing porous pavement and pipeline, establishing a system of collecting and storing rain water. Integrating with garden design to build artificial wetland for sewage disposal is discussed. Retaining the rain water and utilizing sewege as resource are an effective method to achieve the sustainable utilizing of water in city sight gardens.
According to the sustainable development principle, this paper puts forward a new thinking, which includes using concaves to store flood, constructing porous pavement and pipeline, establishing a system of collecting and storing rain water. Integrating with garden design to build artificial wetland for sewage disposal is discussed. Retaining the rain water and utilizing sewege as resource are an effective method to achieve the sustainable utilizing of water in city sight gardens.
2004, 34(1): 29-31,41.
doi: 10.13204/j.gyjz200401008
Abstract:
Shisanhang in Guangzhou is a foreign trade special zone, which has a greatest influence on the turning poing of China's social morphology history. Developing the cultural tourist area of commerical ports at Shisanhang in Guangzhou is the best way to rebuild, modify and utilize the famous historical and cultural relics.The present paper makes an initial study of its planning conception, scenic design, transportation organization and ways of development.
Shisanhang in Guangzhou is a foreign trade special zone, which has a greatest influence on the turning poing of China's social morphology history. Developing the cultural tourist area of commerical ports at Shisanhang in Guangzhou is the best way to rebuild, modify and utilize the famous historical and cultural relics.The present paper makes an initial study of its planning conception, scenic design, transportation organization and ways of development.
2004, 34(1): 32-35,65.
doi: 10.13204/j.gyjz200401009
Abstract:
It is analyzed and discussed that the streassed property of members for an integral transfer structure with large-span laminated open-web trusses, the effect of axial compression of the members on the structure due to prestressing force, the effect of changing the layers of the transfer structure on its internal force and deformation, the rigid relation between the vertical and horizontal members, as well as the principles of aseismic design. Several basic conceptual problems in the design of this structure are also explored, and corresponding proposals are given, which may be a reference for the design of relevant projects.
It is analyzed and discussed that the streassed property of members for an integral transfer structure with large-span laminated open-web trusses, the effect of axial compression of the members on the structure due to prestressing force, the effect of changing the layers of the transfer structure on its internal force and deformation, the rigid relation between the vertical and horizontal members, as well as the principles of aseismic design. Several basic conceptual problems in the design of this structure are also explored, and corresponding proposals are given, which may be a reference for the design of relevant projects.
2004, 34(1): 36-38.
doi: 10.13204/j.gyjz200401010
Abstract:
According to the basic theory of structural reliability and design theory of unbonded partially prestressed concrete structure, based upon extreme theory of random variable and crack number of beam, the system reliability of an unbonded partially prestressed concrete beam is analyzed.
According to the basic theory of structural reliability and design theory of unbonded partially prestressed concrete structure, based upon extreme theory of random variable and crack number of beam, the system reliability of an unbonded partially prestressed concrete beam is analyzed.
2004, 34(1): 39-41.
doi: 10.13204/j.gyjz200401011
Abstract:
Based on the experimental study on a subspace model of the three-span, three-bay R.C frame for a large-scale thermal power plant, this paper mainly analyses the working property and stressed feature of the abnormal joints and the transverse bars strains in abnormal joints. Last, it gives the shear capacity formula for abnormal joints, which may be a reference for designs.
Based on the experimental study on a subspace model of the three-span, three-bay R.C frame for a large-scale thermal power plant, this paper mainly analyses the working property and stressed feature of the abnormal joints and the transverse bars strains in abnormal joints. Last, it gives the shear capacity formula for abnormal joints, which may be a reference for designs.
2004, 34(1): 42-44.
doi: 10.13204/j.gyjz200401012
Abstract:
In the eccentric joint core area of a reinforced concrete frame, the forces are complicated.In seismic area or under some exceptional conditions, eccentric joints are difficult to repair when cracks occur.Adopting spread-ended beam, it can save space, efficiently improve strength and ductility in the eccentric joint core area, and postpone the appearance and development of crack.In this paper, the major study parameters in eccentric joints are eccentricity and spread-ended beam width.Cracking resistance of eccentric beam-column joints are studied from cracking resistance capacity.The applied equation for computing crack resistance capacity is proposed.Compared with the test results, the calculated results are in good agreement with them.
In the eccentric joint core area of a reinforced concrete frame, the forces are complicated.In seismic area or under some exceptional conditions, eccentric joints are difficult to repair when cracks occur.Adopting spread-ended beam, it can save space, efficiently improve strength and ductility in the eccentric joint core area, and postpone the appearance and development of crack.In this paper, the major study parameters in eccentric joints are eccentricity and spread-ended beam width.Cracking resistance of eccentric beam-column joints are studied from cracking resistance capacity.The applied equation for computing crack resistance capacity is proposed.Compared with the test results, the calculated results are in good agreement with them.
2004, 34(1): 45-49.
doi: 10.13204/j.gyjz200401013
Abstract:
Raft design parameter is an important factor to optimal design of high-rise building with pile-raft foundation.In order to know the rafts real stress during building construction, through in-situ test of a superhigh building at loess areaNet Management Center Mansion of Shaanxi Telecom Office, the test data are analyzed and some results such as rafts stress varying with the duration from start of pouring rafts concrete to the seal of the roof of mainbody, rafts stress distribution on middle axial, settlement and piles reaction distribution on middle axial, etc are given.All these provide data for the optimal design of high-rise building with pile-raft foundation.
Raft design parameter is an important factor to optimal design of high-rise building with pile-raft foundation.In order to know the rafts real stress during building construction, through in-situ test of a superhigh building at loess areaNet Management Center Mansion of Shaanxi Telecom Office, the test data are analyzed and some results such as rafts stress varying with the duration from start of pouring rafts concrete to the seal of the roof of mainbody, rafts stress distribution on middle axial, settlement and piles reaction distribution on middle axial, etc are given.All these provide data for the optimal design of high-rise building with pile-raft foundation.
2004, 34(1): 50-53,78.
doi: 10.13204/j.gyjz200401014
Abstract:
It was said that the seismic settlement relates to the earthquake intensity, the endurance period, the soil behavior, the structure intensity, the location and the aseismatic means etc.For the technical application, in order to prevent or reduce the damage of the seismic settlement, besides reinforcing aseismatic facilities, it brings definite social advantage and economic benefit to estimate the magnitude of the seismic settlement via numerical calculation in engineering construction.By the effective stress dynamic response analysis with equivalent linearity, this text utilizes the equivalent nodal force method to analyze the variation tendency of the soft clay seismic settlement of a certain highway foundation along with the seismic peak acceleration, and establishes a formula of the seismic settlement which is related with the embankment height, the soft soil dynamic modular coefficient, the saturated unit weight, the ratio of the amplification factor of the vertical seismic acceleration to the horizontal one and the horizontal seismic coefficient etc.Furthermore, the effect of the frequency spectum on the seismic settlement is still be realized taking on some instructiveness for the correlative research.
It was said that the seismic settlement relates to the earthquake intensity, the endurance period, the soil behavior, the structure intensity, the location and the aseismatic means etc.For the technical application, in order to prevent or reduce the damage of the seismic settlement, besides reinforcing aseismatic facilities, it brings definite social advantage and economic benefit to estimate the magnitude of the seismic settlement via numerical calculation in engineering construction.By the effective stress dynamic response analysis with equivalent linearity, this text utilizes the equivalent nodal force method to analyze the variation tendency of the soft clay seismic settlement of a certain highway foundation along with the seismic peak acceleration, and establishes a formula of the seismic settlement which is related with the embankment height, the soft soil dynamic modular coefficient, the saturated unit weight, the ratio of the amplification factor of the vertical seismic acceleration to the horizontal one and the horizontal seismic coefficient etc.Furthermore, the effect of the frequency spectum on the seismic settlement is still be realized taking on some instructiveness for the correlative research.
2004, 34(1): 54-56.
doi: 10.13204/j.gyjz200401015
Abstract:
In this paper, the study on stable reliability of bracing structure for excavation is engaged in by means of structural reliability theory.By using JC method, the concrete examples stable reliability is calculated and the bounds of whole failure probability under multiple instability modes are obtained.
In this paper, the study on stable reliability of bracing structure for excavation is engaged in by means of structural reliability theory.By using JC method, the concrete examples stable reliability is calculated and the bounds of whole failure probability under multiple instability modes are obtained.
2004, 34(1): 57-59.
doi: 10.13204/j.gyjz200401016
Abstract:
According to Design Specification of Concrete Structure(GB 50010-2002) and actual testing data on cracking resistance and ultimate bending moment of 95 pretensioned spun concrete piles collected by the authors, two revised suggestions are offered for calculation of cracking resistance and ultimate bending moment of pretensioned spun concrete piles through research and analysis, which makes the calculation results be basically in accord with the actual conditions of spun concrete piles-producing factories in China.
According to Design Specification of Concrete Structure(GB 50010-2002) and actual testing data on cracking resistance and ultimate bending moment of 95 pretensioned spun concrete piles collected by the authors, two revised suggestions are offered for calculation of cracking resistance and ultimate bending moment of pretensioned spun concrete piles through research and analysis, which makes the calculation results be basically in accord with the actual conditions of spun concrete piles-producing factories in China.
2004, 34(1): 60-62.
doi: 10.13204/j.gyjz200401017
Abstract:
Based on the experiments, this paper systematically studied the quasi-static mechanical properties of ecological reactive powder concrete(ECO-RPC) with different fiber volume fractions( V f) under uniaxial compression with two strain rates.The experimental results showed that the adding of steel fiber into the ECO-RPC matrix led to not only further strengthening but also remarkably toughening and crack arresting of the composites, and the destruction pattern of ECO-RPC was changed from brittleness to pseudo plasticity.With the increase of the V f, the elastic modulus and Poisson's ratio of ECO-RPC were changed only a little.It was also found that the stress-strain curves of the same mix proportion of ECO-RPC with different strain rate were somewhat similar, with the strength and the peak strain increased but the toughness decreased when the strain rate increased, and the toughness of ECO-RPC matrix decreased more than those of steel fiber reinforced ECO-RPC.
Based on the experiments, this paper systematically studied the quasi-static mechanical properties of ecological reactive powder concrete(ECO-RPC) with different fiber volume fractions( V f) under uniaxial compression with two strain rates.The experimental results showed that the adding of steel fiber into the ECO-RPC matrix led to not only further strengthening but also remarkably toughening and crack arresting of the composites, and the destruction pattern of ECO-RPC was changed from brittleness to pseudo plasticity.With the increase of the V f, the elastic modulus and Poisson's ratio of ECO-RPC were changed only a little.It was also found that the stress-strain curves of the same mix proportion of ECO-RPC with different strain rate were somewhat similar, with the strength and the peak strain increased but the toughness decreased when the strain rate increased, and the toughness of ECO-RPC matrix decreased more than those of steel fiber reinforced ECO-RPC.
2004, 34(1): 63-65.
doi: 10.13204/j.gyjz200401018
Abstract:
The results for the concrete samples from five corroded concrete bridges in Shanghai show lower strength and worse durability during the past decade, a large numbles of bridges, viaducts and city railways were built in Shanghai.The technology and measures of concrete corrosion resistance should be researched in time.The chloride permeability, gas permeability and carbonation resistance of concrete coating by different coats(TC, PA, CA, OS) were studied.The results show that the coats are efficient to protect concrete from corroding except for OS, and PA is the best.
The results for the concrete samples from five corroded concrete bridges in Shanghai show lower strength and worse durability during the past decade, a large numbles of bridges, viaducts and city railways were built in Shanghai.The technology and measures of concrete corrosion resistance should be researched in time.The chloride permeability, gas permeability and carbonation resistance of concrete coating by different coats(TC, PA, CA, OS) were studied.The results show that the coats are efficient to protect concrete from corroding except for OS, and PA is the best.
2004, 34(1): 66-68,75.
doi: 10.13204/j.gyjz200401019
Abstract:
In this paper, a research on the reinforced concrete full-scale three-span continuous slabs under fire was carried out, which underwent the normal loading.From the test, the regularities of the deformation and the temperature distribution were presented, furthermore the characteristics of the internal force redistribution and their destroying features of the reinforced concrete continuous slabs were analysed.The self-made fire-test furnace was used for all the tests, which is reliable and convenient.
In this paper, a research on the reinforced concrete full-scale three-span continuous slabs under fire was carried out, which underwent the normal loading.From the test, the regularities of the deformation and the temperature distribution were presented, furthermore the characteristics of the internal force redistribution and their destroying features of the reinforced concrete continuous slabs were analysed.The self-made fire-test furnace was used for all the tests, which is reliable and convenient.
2004, 34(1): 69-71,17.
doi: 10.13204/j.gyjz200401020
Abstract:
The core of a high anticracking concrete is that sulphoaluminate expansion agent and polyacrylic fiber are taken as high anticracking components of the concrete, with which a mutual reinforcement is obtained to improve remarkably the anticracking of the concrete.The new technology has been used for hub building of Guangzhou New Baiyun International Airport, whose use of compensating shrinkage fiber concrete is more than 40?000m +3.A satisfactory result is obtained for prevention anticreacking of superlong giant concrete structure.It is for the first time to use the compensating shrinkage concrete technique for the construction of a large airport domestically.
The core of a high anticracking concrete is that sulphoaluminate expansion agent and polyacrylic fiber are taken as high anticracking components of the concrete, with which a mutual reinforcement is obtained to improve remarkably the anticracking of the concrete.The new technology has been used for hub building of Guangzhou New Baiyun International Airport, whose use of compensating shrinkage fiber concrete is more than 40?000m +3.A satisfactory result is obtained for prevention anticreacking of superlong giant concrete structure.It is for the first time to use the compensating shrinkage concrete technique for the construction of a large airport domestically.
2004, 34(1): 72-75.
doi: 10.13204/j.gyjz200401021
Abstract:
It is analyzed and discussed that the effect on the structure of different layout schemes of the prestressed bars for an integral transfer structure with large-span laminated open-web trusses; some suggestions are proposed on initially evaluating the presstressed barsarea and the scheme of applying prestresses for this transfer structural system, which provides a reference for design of relevant projects.
It is analyzed and discussed that the effect on the structure of different layout schemes of the prestressed bars for an integral transfer structure with large-span laminated open-web trusses; some suggestions are proposed on initially evaluating the presstressed barsarea and the scheme of applying prestresses for this transfer structural system, which provides a reference for design of relevant projects.
2004, 34(1): 76-78.
doi: 10.13204/j.gyjz200401022
Abstract:
Wether a settlement joint is set between the main tower and its accessory of a high-rise building is the difficult problem obsessing the structural engineer.This article introduces the solution by post-pouring zone with the actual project made by the author.
Wether a settlement joint is set between the main tower and its accessory of a high-rise building is the difficult problem obsessing the structural engineer.This article introduces the solution by post-pouring zone with the actual project made by the author.
2004, 34(1): 79-81.
doi: 10.13204/j.gyjz200401023
Abstract:
The practice situation and theoretical views of all kinds of sustainable architectures in foreign countries are reviewed, which are summarized as six trends; and on the basis of which comparisons and analyses are also carried out.
The practice situation and theoretical views of all kinds of sustainable architectures in foreign countries are reviewed, which are summarized as six trends; and on the basis of which comparisons and analyses are also carried out.
2004, 34(1): 82-84.
doi: 10.13204/j.gyjz200401024
Abstract:
According to Technical Specification for Strengthening Concrete Structures(CECS 25:90), the basic theory of calculation of flexural and shear steel plate-gluing strengthening for RC rectangular beams is introduced, and the software design of their courses is also carried out using Visual Basic 6 0 software. Finally an explanation is done through application examples.
According to Technical Specification for Strengthening Concrete Structures(CECS 25:90), the basic theory of calculation of flexural and shear steel plate-gluing strengthening for RC rectangular beams is introduced, and the software design of their courses is also carried out using Visual Basic 6 0 software. Finally an explanation is done through application examples.
2004, 34(1): 85-86,84.
doi: 10.13204/j.gyjz200401025
Abstract:
There are lots of causes to arouse the cracks in R. C. structures, but the causes come from the imperfect design are concealed, which are difficult to be found, hence the harm of the cracks is more dangerous. In this paper, the detail analyses by the ANSYS5 5 software for the cracks occurred on the playing field floor of a gymnasium in Zhejiang Province are put forward, and then the treatment suggestions are given. The attention points are given for designing a floor with a large space above it and a basement below it.
There are lots of causes to arouse the cracks in R. C. structures, but the causes come from the imperfect design are concealed, which are difficult to be found, hence the harm of the cracks is more dangerous. In this paper, the detail analyses by the ANSYS5 5 software for the cracks occurred on the playing field floor of a gymnasium in Zhejiang Province are put forward, and then the treatment suggestions are given. The attention points are given for designing a floor with a large space above it and a basement below it.
2004, 34(1): 87-89.
doi: 10.13204/j.gyjz200401026
Abstract:
Compared with several structural schemes, we found the strongpoints of a floor system with prestressed concrete sandwich plates, such as lightweight, strong ability to resist crack and low cost. This structural system has a great future.Based on a engineering practice, we give some advices on the design of a floor with prestressed concrete sandwich plates.
Compared with several structural schemes, we found the strongpoints of a floor system with prestressed concrete sandwich plates, such as lightweight, strong ability to resist crack and low cost. This structural system has a great future.Based on a engineering practice, we give some advices on the design of a floor with prestressed concrete sandwich plates.
2004, 34(1): 90-91.
doi: 10.13204/j.gyjz200401027
Abstract:
A courtyard space combination is used for the design of a new campus, which makes the architectural design and that of its outer space be carried out at the same time, so as to create a variegated, graceful and benign campus environment, and gain a different layout from others. Meanwhile the pattern makes architecture style more bountiful, decency and elegant, then we can find variety in unification and get a special effect in art.
A courtyard space combination is used for the design of a new campus, which makes the architectural design and that of its outer space be carried out at the same time, so as to create a variegated, graceful and benign campus environment, and gain a different layout from others. Meanwhile the pattern makes architecture style more bountiful, decency and elegant, then we can find variety in unification and get a special effect in art.
