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2009 Vol. 39, No. 8
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2009, 39(8): 1-3,7.
doi: 10.13204/j.gyjz200908001
Abstract:
A protected historical significant building,which was built in 1940s is the Gothic architecture.Because the building is old-line,the aging and damage of the materials,members and structure of the building are severe,which leads to poor security of the whole structure.Therefore some detection and identification of the security of major structure have been made,and corresponding proposals to the problems of major structure have been given.Which may be a reference for other similar projects.
A protected historical significant building,which was built in 1940s is the Gothic architecture.Because the building is old-line,the aging and damage of the materials,members and structure of the building are severe,which leads to poor security of the whole structure.Therefore some detection and identification of the security of major structure have been made,and corresponding proposals to the problems of major structure have been given.Which may be a reference for other similar projects.
2009, 39(8): 4-7.
doi: 10.13204/j.gyjz200908002
Abstract:
After Wenchuan earthquake,according to the latest code, a grade must be raised for a seismic design of some frame structure buildings in earthquake effected regions,so antiseismic appraisal and dynamical test of the structures must be conducted.If the obtained results show that the structures can not meet the requirements of the current code,they need to be reinforced.Based on a practical project in the earthquake effected regions,it is described aseismic appraisal and strengthening methods,which may supply some experience for a seismic strengthening design of similar projects.
After Wenchuan earthquake,according to the latest code, a grade must be raised for a seismic design of some frame structure buildings in earthquake effected regions,so antiseismic appraisal and dynamical test of the structures must be conducted.If the obtained results show that the structures can not meet the requirements of the current code,they need to be reinforced.Based on a practical project in the earthquake effected regions,it is described aseismic appraisal and strengthening methods,which may supply some experience for a seismic strengthening design of similar projects.
2009, 39(8): 8-12.
doi: 10.13204/j.gyjz200908003
Abstract:
Mechanical properties of two kinds of sandwich beams were tested.The geometric parameters and the ratio of longitudinal bar of the beams were the same,but the types of connections were different.The result indicated that the failure mode,crack shape and development law,ultimate load,and curve of load-deflection were the same as that of the whole poured beam,which had the equal ratio of longitudinal bar.Longitudinal bar played an important role to resist the loads in sandwich beam,while the link steel bar and pin key steel bar did not lend much support to resist the loads.What the link steel bar and pin key steel bar done was that they made the brick wall and concrete beam work together,whose deflections were the same.
Mechanical properties of two kinds of sandwich beams were tested.The geometric parameters and the ratio of longitudinal bar of the beams were the same,but the types of connections were different.The result indicated that the failure mode,crack shape and development law,ultimate load,and curve of load-deflection were the same as that of the whole poured beam,which had the equal ratio of longitudinal bar.Longitudinal bar played an important role to resist the loads in sandwich beam,while the link steel bar and pin key steel bar did not lend much support to resist the loads.What the link steel bar and pin key steel bar done was that they made the brick wall and concrete beam work together,whose deflections were the same.
2009, 39(8): 13-15.
doi: 10.13204/j.gyjz200908004
Abstract:
Combined with the reforming and strengthening project of the steel mill building for a steelmaking workshop,it is researched deeply the reform and strengthening of the structural system of one-story steel mill buildings.It is also analyzed the modal shape and forced features of the structure,thus proposing the strengthening scheme of the structural system,as a result the functions of the building are improved.
Combined with the reforming and strengthening project of the steel mill building for a steelmaking workshop,it is researched deeply the reform and strengthening of the structural system of one-story steel mill buildings.It is also analyzed the modal shape and forced features of the structure,thus proposing the strengthening scheme of the structural system,as a result the functions of the building are improved.
2009, 39(8): 16-19.
doi: 10.13204/j.gyjz200908005
Abstract:
The cracks on the web of box girder for the third Shiqiao Bridge are demonstrated by pictures including the location and geometry of the cracks.The deficiencies of performance and cracks due to the incorrect design of web and the lower shear resistance are discussed.In order to suppress the crack propagation and improve the shear strength of the web,the external prestressing method is proposed after several debates.The formation of external prestressing cable,the arrangements and control stress of tendons are discussed.Some critical aspects,such as deviator and anchorage,are designed carefully.The analytical model is developed by bridge software,the internal forces and stress have been calculated by computer.By comparison,it can be known that the safety margin increases and the crack propagation can be suppressed efficiently.
The cracks on the web of box girder for the third Shiqiao Bridge are demonstrated by pictures including the location and geometry of the cracks.The deficiencies of performance and cracks due to the incorrect design of web and the lower shear resistance are discussed.In order to suppress the crack propagation and improve the shear strength of the web,the external prestressing method is proposed after several debates.The formation of external prestressing cable,the arrangements and control stress of tendons are discussed.Some critical aspects,such as deviator and anchorage,are designed carefully.The analytical model is developed by bridge software,the internal forces and stress have been calculated by computer.By comparison,it can be known that the safety margin increases and the crack propagation can be suppressed efficiently.
2009, 39(8): 20-24,19.
doi: 10.13204/j.gyjz200908006
Abstract:
It is presented an experimental study on 9 pieces of simple supported RC two-way slabs strengthened with external bonded glass fiber reinforced polymer(GFRP) strips.The cracking behavior,deformation behavior,failure characteristic and mechanism and ultimate bearing capacity of strengthened RC two-way slabs were studied.The test results indicated that the GFRP strips were effective in appreciably improving the cracking behavior and deflection behavior and increasing the flexural stiffness,cracking load and ultimate bearing capacity of the strengthened slabs.But the ductility of the strengthened slabs was reduced.The yield-line failure modes of strengthened RC two-way slabs were analyzed based on the experimental results.Based on the regression of test results,the maximum strain of FRP under two-way loading is obtained.By adopting of yield-line theory,a calculation formula for the determination of the ultimate capacity of the strengthened slabs was obtained.The analytical results are in good agreement with the test results.This study may be a reference for actual strengthening projects.
It is presented an experimental study on 9 pieces of simple supported RC two-way slabs strengthened with external bonded glass fiber reinforced polymer(GFRP) strips.The cracking behavior,deformation behavior,failure characteristic and mechanism and ultimate bearing capacity of strengthened RC two-way slabs were studied.The test results indicated that the GFRP strips were effective in appreciably improving the cracking behavior and deflection behavior and increasing the flexural stiffness,cracking load and ultimate bearing capacity of the strengthened slabs.But the ductility of the strengthened slabs was reduced.The yield-line failure modes of strengthened RC two-way slabs were analyzed based on the experimental results.Based on the regression of test results,the maximum strain of FRP under two-way loading is obtained.By adopting of yield-line theory,a calculation formula for the determination of the ultimate capacity of the strengthened slabs was obtained.The analytical results are in good agreement with the test results.This study may be a reference for actual strengthening projects.
2009, 39(8): 25-27.
doi: 10.13204/j.gyjz200908007
Abstract:
According to practice of projects,it is summarized that the basic steps and methods of appraising safety of members for a concrete structure after fire;and several common strengthening methods are also proposed in light of difference in damage to members after fire.
According to practice of projects,it is summarized that the basic steps and methods of appraising safety of members for a concrete structure after fire;and several common strengthening methods are also proposed in light of difference in damage to members after fire.
2009, 39(8): 28-29,37.
doi: 10.13204/j.gyjz200908008
Abstract:
Ferrocement mortar is a new method of reinforcement,and can be used for seismic reinforcement of masonry structure.The strengthening mechanism of ferrocement mortar and the causation of the quality defect are introduced,control measures are then emphasized from five aspects: the raw material and mixture ratio,wall treatment,reinforcement project etc.
Ferrocement mortar is a new method of reinforcement,and can be used for seismic reinforcement of masonry structure.The strengthening mechanism of ferrocement mortar and the causation of the quality defect are introduced,control measures are then emphasized from five aspects: the raw material and mixture ratio,wall treatment,reinforcement project etc.
2009, 39(8): 30-33.
doi: 10.13204/j.gyjz200908009
Abstract:
The concept of industrial landscape was emphasized in the planning and design of the new zone of Baiyunbian Industrial Park,with which the common single industrial image was decomposed.The village style residential groups were formed by organic scattered layout of the Chinese traditional residential patterns to resolve the damage to urban landscape space by mill buildings.The planning of Baiyunbian Industrial Park compromises the conception of corporation brand culture construction for industrial tourism,so as to make the industrial park be not only a production base,but also a carrier of the corporation culture,which will embody its social responsibility and value by a positive and constructive conception.
The concept of industrial landscape was emphasized in the planning and design of the new zone of Baiyunbian Industrial Park,with which the common single industrial image was decomposed.The village style residential groups were formed by organic scattered layout of the Chinese traditional residential patterns to resolve the damage to urban landscape space by mill buildings.The planning of Baiyunbian Industrial Park compromises the conception of corporation brand culture construction for industrial tourism,so as to make the industrial park be not only a production base,but also a carrier of the corporation culture,which will embody its social responsibility and value by a positive and constructive conception.
2009, 39(8): 34-37.
doi: 10.13204/j.gyjz200908010
Abstract:
The sustainable development is one of basic policies in our country.Its connotation consists of the continuous rise,the immortal use of resources,the continuation of traditional culture and the maintaining of the natural vitality.The ecological construction is the important measure for the implementation of sustainable development.A stimulating value of sustainability has direct architecture and landscape design back towards climate responsiveness.The benefits associated with bioclimatic design are economic,environmental and aesthetic;which all comply with the objectives of sustainability.Sustainability is a universal concept,yet requires unique measures when applied in different contexts.What the thesis of this dissertation is the climatic effect on architecture and landscape's characters.
The sustainable development is one of basic policies in our country.Its connotation consists of the continuous rise,the immortal use of resources,the continuation of traditional culture and the maintaining of the natural vitality.The ecological construction is the important measure for the implementation of sustainable development.A stimulating value of sustainability has direct architecture and landscape design back towards climate responsiveness.The benefits associated with bioclimatic design are economic,environmental and aesthetic;which all comply with the objectives of sustainability.Sustainability is a universal concept,yet requires unique measures when applied in different contexts.What the thesis of this dissertation is the climatic effect on architecture and landscape's characters.
2009, 39(8): 38-40,75.
doi: 10.13204/j.gyjz200908011
Abstract:
Taking the city of Shanghai for example,which is experiencing the relatively rapid process of urban modernization,from the perspective of the city and the viewpoint of general public,it is analysed the problems of the old industrial buildings,in particular,the key issues of the transformation of old factory buildings;through analyzing the actual situation of their reconstruction,it is intended to find out the effective and suitable strategies for transformation of old factory buildings in China in order to enhance the integrated value of the existing old industrial buildings.
Taking the city of Shanghai for example,which is experiencing the relatively rapid process of urban modernization,from the perspective of the city and the viewpoint of general public,it is analysed the problems of the old industrial buildings,in particular,the key issues of the transformation of old factory buildings;through analyzing the actual situation of their reconstruction,it is intended to find out the effective and suitable strategies for transformation of old factory buildings in China in order to enhance the integrated value of the existing old industrial buildings.
2009, 39(8): 41-45,12.
doi: 10.13204/j.gyjz200908012
Abstract:
Based on the time-history analysis of the elastic-plastic wind-induced response for a tall building structure under the strong breeze,the feasibility of the application of Pushover method to the wind resistance design of the structure is investigated.Through a series of comparative analyses for computational results of different methods,it is found that the tall building structures under the weak wind load are generally in the elastic state.The structural responses obtained by using the static-equivalent wind-load method in the code may meet the needs of practical projects.But under the strong breeze,some moments of the tall building structure would enter the plastic deformation state,the displacement responses provided by the Pushover method are in good agreement with the results of the time-history analysis,and the results of the static-equivalent wind-load method is unsafety.
Based on the time-history analysis of the elastic-plastic wind-induced response for a tall building structure under the strong breeze,the feasibility of the application of Pushover method to the wind resistance design of the structure is investigated.Through a series of comparative analyses for computational results of different methods,it is found that the tall building structures under the weak wind load are generally in the elastic state.The structural responses obtained by using the static-equivalent wind-load method in the code may meet the needs of practical projects.But under the strong breeze,some moments of the tall building structure would enter the plastic deformation state,the displacement responses provided by the Pushover method are in good agreement with the results of the time-history analysis,and the results of the static-equivalent wind-load method is unsafety.
2009, 39(8): 46-51.
doi: 10.13204/j.gyjz200908013
Abstract:
Support structure system of air cooled condenser is a new industrial construction,whose wind load parameters are not very clear and the proposed wind parameter in present load code can't be directly used.According to the character of this kind of structure,a rigid model with 1∶150 scaling factor was made, and the wind tunnel test about mean wind pressure on wind-break wall surface was carried out.In this paper,wind tunnel test for wind pressure distribution on wind-break wall surface and test data processing were presented in detail.Moreover,several important attributes to wind pressure distribution were discussed.Conclusions given by this paper have important guiding meanings for the wind resistance design of this kind of structure.
Support structure system of air cooled condenser is a new industrial construction,whose wind load parameters are not very clear and the proposed wind parameter in present load code can't be directly used.According to the character of this kind of structure,a rigid model with 1∶150 scaling factor was made, and the wind tunnel test about mean wind pressure on wind-break wall surface was carried out.In this paper,wind tunnel test for wind pressure distribution on wind-break wall surface and test data processing were presented in detail.Moreover,several important attributes to wind pressure distribution were discussed.Conclusions given by this paper have important guiding meanings for the wind resistance design of this kind of structure.
2009, 39(8): 52-56,51.
doi: 10.13204/j.gyjz200908014
Abstract:
According to the previous researches and experiments,the rigid frameequivalent brace model of multi-ribbed slab structure is put forward,in which the multi-ribbed composite wall is equivalent to a whole diagonal brace.Based on the previous tests,the main parameters and the plastic hinge settings of the model are established.By using this model,a shaking table test of a multi-ribbed slab structure model is simulated.And the calculation results tally well with the experimental results in acceleration time history,response waveform and the maximum displacement of monitoring points.The results indicate that the rigid frame-equivalent brace model can better reflect the dynamic characteristics and elastic-plastic deformation situation of the prototype structure.Thus this model can be applied to elastic-plastic time-history analysis and nonlinear deformation checking of multi-ribbed slab structure.
According to the previous researches and experiments,the rigid frameequivalent brace model of multi-ribbed slab structure is put forward,in which the multi-ribbed composite wall is equivalent to a whole diagonal brace.Based on the previous tests,the main parameters and the plastic hinge settings of the model are established.By using this model,a shaking table test of a multi-ribbed slab structure model is simulated.And the calculation results tally well with the experimental results in acceleration time history,response waveform and the maximum displacement of monitoring points.The results indicate that the rigid frame-equivalent brace model can better reflect the dynamic characteristics and elastic-plastic deformation situation of the prototype structure.Thus this model can be applied to elastic-plastic time-history analysis and nonlinear deformation checking of multi-ribbed slab structure.
2009, 39(8): 57-61.
doi: 10.13204/j.gyjz200908015
Abstract:
Based on the time-history analysis of the elastic-plastic wind-induced response for a tall building structure under the strong breeze,the feasibility of the application of Pushover method to the wind resistance design of the structure is investigated.Through a series of comparative analyses for computational results of different methods,it is found that the tall building structures under the weak wind load are generally in the elastic state.The structural responses obtained by using the static-equivalent wind-load method in the code may meet the needs of practical projects.But under the strong breeze,some moments of the tall building structure would enter the plastic deformation state,the displacement responses provided by the Pushover method are in good agreement with the results of the time-history analysis,and the results of the static-equivalent wind-load method is unsafety.
Based on the time-history analysis of the elastic-plastic wind-induced response for a tall building structure under the strong breeze,the feasibility of the application of Pushover method to the wind resistance design of the structure is investigated.Through a series of comparative analyses for computational results of different methods,it is found that the tall building structures under the weak wind load are generally in the elastic state.The structural responses obtained by using the static-equivalent wind-load method in the code may meet the needs of practical projects.But under the strong breeze,some moments of the tall building structure would enter the plastic deformation state,the displacement responses provided by the Pushover method are in good agreement with the results of the time-history analysis,and the results of the static-equivalent wind-load method is unsafety.
2009, 39(8): 62-64,117.
doi: 10.13204/j.gyjz200908016
Abstract:
The formation of a rigid matrix is given by analysing crevices of a masonry structure.It is simulated that the walls collapse for increasing cracks in walls under action of earthquake by FEM,and the characteristic of vibration and collapse in the structure is concluded.The method given in the paper can also be used in other structures made of brittle materials.
The formation of a rigid matrix is given by analysing crevices of a masonry structure.It is simulated that the walls collapse for increasing cracks in walls under action of earthquake by FEM,and the characteristic of vibration and collapse in the structure is concluded.The method given in the paper can also be used in other structures made of brittle materials.
2009, 39(8): 65-68.
doi: 10.13204/j.gyjz200908017
Abstract:
According to the characteristics of the prestressed composite soil nailing walls,a new type of prediction deformation model is constructedVerhulst model through analyzing the operation mechanism and influential factors during excavation and use of the walls,which is used to assess the deformation of prestressed composite soil nailing walls to provide effective evidence for the design.
According to the characteristics of the prestressed composite soil nailing walls,a new type of prediction deformation model is constructedVerhulst model through analyzing the operation mechanism and influential factors during excavation and use of the walls,which is used to assess the deformation of prestressed composite soil nailing walls to provide effective evidence for the design.
2009, 39(8): 69-71,100.
doi: 10.13204/j.gyjz200908018
Abstract:
In marine soft ground,the prestressed tubular concrete pile(PTC Pile) driven by hammering method induces the increase in excess pore water pressure(EPWP).The following results are obtained by field test.The excess pore water pressure increases with time during pile installation and dissipates with time after installation.The maximum EPWP reaches as high as 80 kPa.The dissipation time of excess pore pressure varies with the time and the distance from the pile.As 1 month elapsed after installation,the residual EPWP remains still with the value in the range of 10 to 20 kPa.The accumulations of EPWP in group piles driving cause the high level stress in the ground.Therefore,the rational measures for controlling the excess pore water pressure pile installation should be taken during installation of group piles.
In marine soft ground,the prestressed tubular concrete pile(PTC Pile) driven by hammering method induces the increase in excess pore water pressure(EPWP).The following results are obtained by field test.The excess pore water pressure increases with time during pile installation and dissipates with time after installation.The maximum EPWP reaches as high as 80 kPa.The dissipation time of excess pore pressure varies with the time and the distance from the pile.As 1 month elapsed after installation,the residual EPWP remains still with the value in the range of 10 to 20 kPa.The accumulations of EPWP in group piles driving cause the high level stress in the ground.Therefore,the rational measures for controlling the excess pore water pressure pile installation should be taken during installation of group piles.
2009, 39(8): 72-75.
doi: 10.13204/j.gyjz200908019
Abstract:
The fatigue tests of flexural tension-compression under constant amplitude cyclic loading have been carried out on pre-stressed concrete cantilever plates against the fatigue state of flexural tension-compression in pre-stressed concrete noise barrier used in high-speed railway.The results of the tests have been presented in the relationship of S-N and compared with those obtained by other researchers.It is also analyzed that tensile fatigue strength of the concrete and the loss rate of effective pre-stress under cyclic loading based on the results of the experiment.The results show that the fatigue capacity of concrete under flexural tension-compression is better than that under axial tension-compression.The loss rate of effective pre-stress under cyclic loading ranged from 3%～6%.The results of investigation furnish the evidence for the design and analysis of fatigue crack resistance for pre-stressed concrete structure under cyclic loading.
The fatigue tests of flexural tension-compression under constant amplitude cyclic loading have been carried out on pre-stressed concrete cantilever plates against the fatigue state of flexural tension-compression in pre-stressed concrete noise barrier used in high-speed railway.The results of the tests have been presented in the relationship of S-N and compared with those obtained by other researchers.It is also analyzed that tensile fatigue strength of the concrete and the loss rate of effective pre-stress under cyclic loading based on the results of the experiment.The results show that the fatigue capacity of concrete under flexural tension-compression is better than that under axial tension-compression.The loss rate of effective pre-stress under cyclic loading ranged from 3%～6%.The results of investigation furnish the evidence for the design and analysis of fatigue crack resistance for pre-stressed concrete structure under cyclic loading.
2009, 39(8): 76-79.
doi: 10.13204/j.gyjz200908020
Abstract:
The paper presents the results of an experimental and numerical investigation into the behaviour of carbon-fiber-reinforced epoxy tubes subjected to monotonic uniaxial loading.These tubes were winded by carbon fibers with a filament winding pattern of [(90/0)_2]_S.Two sizes of tubes were tested in a testing machine to investigate basic properties under uniaxial compression and tension loading.The resulting stress and strain curves were analyzed and the damage and failure modes were observed.It is shown that the ultimate stress and strain under tension are much larger than those under compression,however,the elastic module under these two states are similar if the CFRP tubes are winded with a filament winding pattern of 90/0.
The paper presents the results of an experimental and numerical investigation into the behaviour of carbon-fiber-reinforced epoxy tubes subjected to monotonic uniaxial loading.These tubes were winded by carbon fibers with a filament winding pattern of [(90/0)_2]_S.Two sizes of tubes were tested in a testing machine to investigate basic properties under uniaxial compression and tension loading.The resulting stress and strain curves were analyzed and the damage and failure modes were observed.It is shown that the ultimate stress and strain under tension are much larger than those under compression,however,the elastic module under these two states are similar if the CFRP tubes are winded with a filament winding pattern of 90/0.
2009, 39(8): 80-83.
doi: 10.13204/j.gyjz200908021
Abstract:
It is conducted an experimental study on the flexural performance of 6 CFRP strengthened RC beams.Test results show that under certain conditions,when substituting GFRP U-hoops for partial CFRP U-hoops,the reinforcement effect will be about the same,but it can effectively reduce the cost of reinforcement,the test results provide a reference for engineering practice.CFRP reinforced concrete beams nonlinear problems can be simulated by ANSYS,the results are closer to those of the test,i.e.a difference is in 10%,hence to some extent,it can substitute for test analysis.
It is conducted an experimental study on the flexural performance of 6 CFRP strengthened RC beams.Test results show that under certain conditions,when substituting GFRP U-hoops for partial CFRP U-hoops,the reinforcement effect will be about the same,but it can effectively reduce the cost of reinforcement,the test results provide a reference for engineering practice.CFRP reinforced concrete beams nonlinear problems can be simulated by ANSYS,the results are closer to those of the test,i.e.a difference is in 10%,hence to some extent,it can substitute for test analysis.
2009, 39(8): 84-95.
doi: 10.13204/j.gyjz200908022
Abstract:
It is introduced that the derivation,types,characteristics,principles for the location of the bulbs and branches,comprehensively estimating method for ultimate bearing capacity,calculation formula of vertical compressional bearing capacity,calculation formula of compressive bearing capacity of shaft of DX pile and structure of DX extruding device.Through the static loading tests for 24 DX piles and 3 DX piles with large scale field model,where the reinforcement stress detectors or electrial resistance strain gauges were embedded,the regular patterns and characteristics of mechanisms of bearing capacity of DX piles are systemically studied,and the developments and the distributions of the skin-friction resistances,the bulb resistances and the tip resistances under ultimate and working conditions are detailedly analysed,the developments of the unit skin-friction resistances of each sections of DX piles and the unit bulb resistances and the unit tip resistances of DX piles are systemically studied.The differences of load transfer mechanisms between DX piles and uniform bored piles,and the differences of mechanisms between compressive and tensional DX piles are also comparatively analysed.Finally,how to guarantee the static loading test so that to obtain the full useful data of the mechanisms of bearing capacities also are indicated.
It is introduced that the derivation,types,characteristics,principles for the location of the bulbs and branches,comprehensively estimating method for ultimate bearing capacity,calculation formula of vertical compressional bearing capacity,calculation formula of compressive bearing capacity of shaft of DX pile and structure of DX extruding device.Through the static loading tests for 24 DX piles and 3 DX piles with large scale field model,where the reinforcement stress detectors or electrial resistance strain gauges were embedded,the regular patterns and characteristics of mechanisms of bearing capacity of DX piles are systemically studied,and the developments and the distributions of the skin-friction resistances,the bulb resistances and the tip resistances under ultimate and working conditions are detailedly analysed,the developments of the unit skin-friction resistances of each sections of DX piles and the unit bulb resistances and the unit tip resistances of DX piles are systemically studied.The differences of load transfer mechanisms between DX piles and uniform bored piles,and the differences of mechanisms between compressive and tensional DX piles are also comparatively analysed.Finally,how to guarantee the static loading test so that to obtain the full useful data of the mechanisms of bearing capacities also are indicated.
2009, 39(8): 96-100.
doi: 10.13204/j.gyjz200908023
Abstract:
To completely investigate aseismic behavior of composite beam-CFST(concrete filled square steel tubular) column frame structures,parameter analysis of the typical 15-story frame structure is conducted.The effect of the parameters,such as steel ratio of the column section,thickness of the floor slab and height of the steel beam on the seismic behavior of the structure is discussed.The analytic results show that the height of the steel beam has the most notable effect on the period and elastic displacement of the structure,and the steel ratio of column section takes the secondary place.And with the increment of the height of the steel beam and the steel ratio of the column section,the period and the elastic displacement of the structure decrease in different degrees.The effect of the floor thickness on the initial stiffness and the ultimate bearing capacity is the most remarkable and the effect of the height of the steel beam takes second place.With the increment of the thickness of the floor slab and the height of the steel beam,the initial stiffness and the ultimate bearing capacity of the structure are increased in different degrees.The height of the steel beam has the greatest effect on the elasto-plastic displacement of the structure.And when the height of the steel beam is increased,the elasto-plastic displacement of the structure is reduced remarkably.According to the results of the parameter analysis,we have a simple and intuitionistic impression on the effect of different design parameters on the seismic behavior of the structure.So during the design course,design parameters can be adjusted pertinently,based on the results of the parameter analysis,which makes the optimization of structure design more quick and exact.
To completely investigate aseismic behavior of composite beam-CFST(concrete filled square steel tubular) column frame structures,parameter analysis of the typical 15-story frame structure is conducted.The effect of the parameters,such as steel ratio of the column section,thickness of the floor slab and height of the steel beam on the seismic behavior of the structure is discussed.The analytic results show that the height of the steel beam has the most notable effect on the period and elastic displacement of the structure,and the steel ratio of column section takes the secondary place.And with the increment of the height of the steel beam and the steel ratio of the column section,the period and the elastic displacement of the structure decrease in different degrees.The effect of the floor thickness on the initial stiffness and the ultimate bearing capacity is the most remarkable and the effect of the height of the steel beam takes second place.With the increment of the thickness of the floor slab and the height of the steel beam,the initial stiffness and the ultimate bearing capacity of the structure are increased in different degrees.The height of the steel beam has the greatest effect on the elasto-plastic displacement of the structure.And when the height of the steel beam is increased,the elasto-plastic displacement of the structure is reduced remarkably.According to the results of the parameter analysis,we have a simple and intuitionistic impression on the effect of different design parameters on the seismic behavior of the structure.So during the design course,design parameters can be adjusted pertinently,based on the results of the parameter analysis,which makes the optimization of structure design more quick and exact.
2009, 39(8): 101-105,110.
doi: 10.13204/j.gyjz200908024
Abstract:
In order to investigate the aseismic performance of mid-rise RC composite shear walls with concealed steel truss,the low-frequency quasi-static cyclic loading experiments on six 1/3 scale mid-rise shear walls,including two usual shear walls,two shear walls with concealed steel frame and two shear walls with concealed steel truss,were carried out.The shear wall specimens were given an axial compression ratio of 0.2 or 0.5.Based upon the experimental study,load-carrying capacity,the stiffness,ductility,hysteretic property,energy dissipation capacity and failure phenomena of each shear wall were comparatively analyzed.The experimental results show that compared with the usual shear walls,the seismic performance of the shear wall with concealed steel truss is obviously improved.Compared with the shear walls with low axial compression ratio,the load-carrying capacity of the shear walls with high axial compression ratio is significantly improved,but its ductility and energy dissipation capacity are decreased.
In order to investigate the aseismic performance of mid-rise RC composite shear walls with concealed steel truss,the low-frequency quasi-static cyclic loading experiments on six 1/3 scale mid-rise shear walls,including two usual shear walls,two shear walls with concealed steel frame and two shear walls with concealed steel truss,were carried out.The shear wall specimens were given an axial compression ratio of 0.2 or 0.5.Based upon the experimental study,load-carrying capacity,the stiffness,ductility,hysteretic property,energy dissipation capacity and failure phenomena of each shear wall were comparatively analyzed.The experimental results show that compared with the usual shear walls,the seismic performance of the shear wall with concealed steel truss is obviously improved.Compared with the shear walls with low axial compression ratio,the load-carrying capacity of the shear walls with high axial compression ratio is significantly improved,but its ductility and energy dissipation capacity are decreased.
2009, 39(8): 106-110.
doi: 10.13204/j.gyjz200908025
Abstract:
Overall shear buckling is one of the decisive failure modes of skin diaphragms.It is carried out shear experimental investigation on six skin diaphragms,which are constituted by common YX20-166-830 profiled steel sheeting.Modes of boundary attachment of the six skin diaphragms are different with each other,including one bolt in every trough,one bolt in every crest,two bolts in every trough,two bolts in every trough and one bolt in every crest,one clamped attachment and two dot welds in every trough.The results of experimental investigation are presented including failure process,load-deflection curve,buckling mode,buckling strength,shear stiffness and strain condition,which are influenced by the boundary condition of skin diaphragms.The conclusion provides a reference for strength design of skin diaphragms.
Overall shear buckling is one of the decisive failure modes of skin diaphragms.It is carried out shear experimental investigation on six skin diaphragms,which are constituted by common YX20-166-830 profiled steel sheeting.Modes of boundary attachment of the six skin diaphragms are different with each other,including one bolt in every trough,one bolt in every crest,two bolts in every trough,two bolts in every trough and one bolt in every crest,one clamped attachment and two dot welds in every trough.The results of experimental investigation are presented including failure process,load-deflection curve,buckling mode,buckling strength,shear stiffness and strain condition,which are influenced by the boundary condition of skin diaphragms.The conclusion provides a reference for strength design of skin diaphragms.
2009, 39(8): 111-113.
doi: 10.13204/j.gyjz200908026
Abstract:
Regarding the crane load as a stochastic process,an analybic method of steel crane beams in service is proposed based on Miner cumulative fatigue-damage.It is used to assess the fatigue reliability varing with time of a steel crane beam in service.The result shows that the fatigue reliability of the steel crane beam in service decreases with the increasing of the time,which can predict the residual fatingue life of the steel crane beam.
Regarding the crane load as a stochastic process,an analybic method of steel crane beams in service is proposed based on Miner cumulative fatigue-damage.It is used to assess the fatigue reliability varing with time of a steel crane beam in service.The result shows that the fatigue reliability of the steel crane beam in service decreases with the increasing of the time,which can predict the residual fatingue life of the steel crane beam.
2009, 39(8): 114-117.
doi: 10.13204/j.gyjz200908027
Abstract:
Monotonic static tests were conducted on the four groups of full-scale cast-in-place(RC) nodes and composite(PC) ones of beam-and-girder which were composed of precast inverted T-girder.The contrast experiments indicated that both of the PC and RC nodes failed in beams' bending;the assumption of plane section was basically fulfilled in every kind of PC beams throughout the whole testing process;the values of crack-resisting and bending-resisting bearing capacity.Which were calculated according to China codes were safe.
Monotonic static tests were conducted on the four groups of full-scale cast-in-place(RC) nodes and composite(PC) ones of beam-and-girder which were composed of precast inverted T-girder.The contrast experiments indicated that both of the PC and RC nodes failed in beams' bending;the assumption of plane section was basically fulfilled in every kind of PC beams throughout the whole testing process;the values of crack-resisting and bending-resisting bearing capacity.Which were calculated according to China codes were safe.
2009, 39(8): 118-120.
doi: 10.13204/j.gyjz200908028
Abstract:
The calculation formula of the least ratio of the nonprestressed reinforcement in partially prestressed concrete beams with HRB500 steel bar is deduced.And some suggestions on the least ratio of the nonprestressed reinforcement in partially prestressed concrete beams with HRB500 steel bar are proposed based on each industry standard of the least ratio of the nonprestressed reinforcement at home.Which provided a reference for using HRB500 steel bar in China code for design of concrete structures.
The calculation formula of the least ratio of the nonprestressed reinforcement in partially prestressed concrete beams with HRB500 steel bar is deduced.And some suggestions on the least ratio of the nonprestressed reinforcement in partially prestressed concrete beams with HRB500 steel bar are proposed based on each industry standard of the least ratio of the nonprestressed reinforcement at home.Which provided a reference for using HRB500 steel bar in China code for design of concrete structures.
RESEARCH ON THE DURABILITY OF CORRODED RC BEAMS STRENGTHENED WITH CARBON FIBERS IN MARINE CONDITIONS
2009, 39(8): 120-124.
doi: 10.13204/j.gyjz200908029
Abstract:
It is carried out a study on the durability of corroded RC beams strengthened by CFRP,it is mainly analysed the changes in all mechanical indexes and durability index of the reinfored members under loading,The experimental result and theoretical analysis show that not only the reliability index of concrete structure,but also the resistance to corrosion can be enhanced inevitably.However there are different results according to different methods of reinforcement.
It is carried out a study on the durability of corroded RC beams strengthened by CFRP,it is mainly analysed the changes in all mechanical indexes and durability index of the reinfored members under loading,The experimental result and theoretical analysis show that not only the reliability index of concrete structure,but also the resistance to corrosion can be enhanced inevitably.However there are different results according to different methods of reinforcement.
2009, 39(8): 125-127.
doi: 10.13204/j.gyjz200908030
Abstract:
It is expounded the prospects of use of bamboo in building circle in the future by means of the feasibility of bamboo being used as building material nowadays,as well as its utilization examples of buildings at present.
It is expounded the prospects of use of bamboo in building circle in the future by means of the feasibility of bamboo being used as building material nowadays,as well as its utilization examples of buildings at present.
