Login
Register
E-alert
2010 Vol. 40, No. 10
Display Method:
2010, 40(10): 1-5.
doi: 10.13204/j.gyjz201010001
Abstract:
The time-dependent reliability index of the consolidated reinforced concrete bridges is investigated.A finite element model for a consolidated bridge on the Changjiang River is established,with which a sensitivity analysis is done for the factors impacting the deflection of the consolidated bridge.Based on the response surface method,the time-dependent reliability index of the bridge under serviceability limit state is calculated and the residual service life is predicted.
The time-dependent reliability index of the consolidated reinforced concrete bridges is investigated.A finite element model for a consolidated bridge on the Changjiang River is established,with which a sensitivity analysis is done for the factors impacting the deflection of the consolidated bridge.Based on the response surface method,the time-dependent reliability index of the bridge under serviceability limit state is calculated and the residual service life is predicted.
2010, 40(10): 6-10.
doi: 10.13204/j.gyjz201010002
Abstract:
There were various cracks occurred during the construction of piers for a railway bridge.After comprehensive analysis,an effective method was accepted,with which structural adhesives were filled into the cracks firstly,then the cracks were sealed by high-strength reinforced concrete.In order to demonstrate the reliability of this reinforcement design,ANSYS FEM software was used to simulate and analyse the piers.The differences of stresses and linear stiffness and eccentricities of the piers were analyzed for un-cracked,cracked and strengthened conditions.The results show that the reinforcement design is safe and reliable.It can be used for reference of reinforcement design of similar piers with cracks.
There were various cracks occurred during the construction of piers for a railway bridge.After comprehensive analysis,an effective method was accepted,with which structural adhesives were filled into the cracks firstly,then the cracks were sealed by high-strength reinforced concrete.In order to demonstrate the reliability of this reinforcement design,ANSYS FEM software was used to simulate and analyse the piers.The differences of stresses and linear stiffness and eccentricities of the piers were analyzed for un-cracked,cracked and strengthened conditions.The results show that the reinforcement design is safe and reliable.It can be used for reference of reinforcement design of similar piers with cracks.
2010, 40(10): 11-14.
doi: 10.13204/j.gyjz201010003
Abstract:
With the increase of traffic volumn and the improvement of load grade,the issue of old bridge reinforcement becomes more prominent.In order to study the structural performance of large-span rigid frame bridges strengthened by external prestressing tendons and the spatial stress distribution of anchor blocks,the finite element program ANSYS is used to analyzed respectively the load bearing capacity of the strengthened continuous rigid frame bridge with the main span of 160 m and the spatial stresses of side-span anchor block.The results show that external prestressing can enhance the carrying capacity effectively and improve structural performance significantly,and large-span continuous rigid frame bridge strengthened by external prestressing tendons is effective and practicable;meanwhile,it is pointed out that the principal tensile stresses of the box girder at anchorage zone are existing in the box girder edge and the crossover port edge are also described.The results can provide a reference for the reinforcement of similar bridges.
With the increase of traffic volumn and the improvement of load grade,the issue of old bridge reinforcement becomes more prominent.In order to study the structural performance of large-span rigid frame bridges strengthened by external prestressing tendons and the spatial stress distribution of anchor blocks,the finite element program ANSYS is used to analyzed respectively the load bearing capacity of the strengthened continuous rigid frame bridge with the main span of 160 m and the spatial stresses of side-span anchor block.The results show that external prestressing can enhance the carrying capacity effectively and improve structural performance significantly,and large-span continuous rigid frame bridge strengthened by external prestressing tendons is effective and practicable;meanwhile,it is pointed out that the principal tensile stresses of the box girder at anchorage zone are existing in the box girder edge and the crossover port edge are also described.The results can provide a reference for the reinforcement of similar bridges.
2010, 40(10): 15-18,81.
doi: 10.13204/j.gyjz201010004
Abstract:
There is a dangerous bridge over Beiraoyang River in Fuxin city,carbon fiber reinforced polymer(CFRP) reinforcement plan is presented combining with this project case.To verify the reinforcement effect,finite element analysis of both reinforced and unreinforced triple-rib arched girder with static loading is completed.The results of stress and deformation show that CFRP can reduce deflection and increase bearing capacity of the bridge.The analysis of principal stress and displacement response of both reinforced and unreinforced bridge show that both strength and stiffness of the structure can be increased by sticking CFRP,and anti-seismic performance of the RC bridge is improved remarkably.
There is a dangerous bridge over Beiraoyang River in Fuxin city,carbon fiber reinforced polymer(CFRP) reinforcement plan is presented combining with this project case.To verify the reinforcement effect,finite element analysis of both reinforced and unreinforced triple-rib arched girder with static loading is completed.The results of stress and deformation show that CFRP can reduce deflection and increase bearing capacity of the bridge.The analysis of principal stress and displacement response of both reinforced and unreinforced bridge show that both strength and stiffness of the structure can be increased by sticking CFRP,and anti-seismic performance of the RC bridge is improved remarkably.
2010, 40(10): 19-22.
doi: 10.13204/j.gyjz201010005
Abstract:
The cracks on the box girder surface of a viaduct in Panyu District of Guangzhou City are found,whose reason has been inferred as the deficiency of torsion resistance.In this paper,three rehabilitation methods,additional prestressing concrete transverse beam,additional concrete joist beam and additional steel transverse beam,have been proposed,which advantages and disadvantages have been discussed and contrasted.At last the method of additional steel transverse beam is adopted to improved the torsion resistance,based on those facts of construction convenience,project cost,rehabilitation effectiveness and configuration.The details of rehabilitation design have been exhaustively illustrated.The rehabilitated bridge with beautiful appearance obtains good results.This case can be regarded as a valuable reference for seminar engineering design.
The cracks on the box girder surface of a viaduct in Panyu District of Guangzhou City are found,whose reason has been inferred as the deficiency of torsion resistance.In this paper,three rehabilitation methods,additional prestressing concrete transverse beam,additional concrete joist beam and additional steel transverse beam,have been proposed,which advantages and disadvantages have been discussed and contrasted.At last the method of additional steel transverse beam is adopted to improved the torsion resistance,based on those facts of construction convenience,project cost,rehabilitation effectiveness and configuration.The details of rehabilitation design have been exhaustively illustrated.The rehabilitated bridge with beautiful appearance obtains good results.This case can be regarded as a valuable reference for seminar engineering design.
2010, 40(10): 23-25,135.
doi: 10.13204/j.gyjz201010006
Abstract:
In this paper the collapse of Boulevard de la Concorde Overpass in Canada on September 30,2006 is investigated.The record of visual inspection,sequence of the collapse,the failure surface and the progress of damages to the overpass are researched and the reasons for the collapse are summarized.Also,some suggestions are given on assuring the safety of the bridges in China according to the real conditions of these bridges.
In this paper the collapse of Boulevard de la Concorde Overpass in Canada on September 30,2006 is investigated.The record of visual inspection,sequence of the collapse,the failure surface and the progress of damages to the overpass are researched and the reasons for the collapse are summarized.Also,some suggestions are given on assuring the safety of the bridges in China according to the real conditions of these bridges.
2010, 40(10): 26-30,40.
doi: 10.13204/j.gyjz201010007
Abstract:
Construction monitoring has been widely used in long-span bridges construction of high-speed railway.Combining with the construction monitoring of Jinghang Grand Canal(75 + 125 + 75)m prestressed continuous beam,it is introduced some key technologies and application methods of the deformation control and stress control,including: setting of the camber,determination of the bailey truss deformation,deformation prediction based on probability analysis,stress analysis of sensor data,analysis of temperature effect and controlling method,etc.it is done a calculation of concrete continuous beam deformation control.It is proved by construction practice that the monitoring results are satisfactory,which show the reliability and applicability of this monitoring method,which also provides a reference for similar bridge construction.
Construction monitoring has been widely used in long-span bridges construction of high-speed railway.Combining with the construction monitoring of Jinghang Grand Canal(75 + 125 + 75)m prestressed continuous beam,it is introduced some key technologies and application methods of the deformation control and stress control,including: setting of the camber,determination of the bailey truss deformation,deformation prediction based on probability analysis,stress analysis of sensor data,analysis of temperature effect and controlling method,etc.it is done a calculation of concrete continuous beam deformation control.It is proved by construction practice that the monitoring results are satisfactory,which show the reliability and applicability of this monitoring method,which also provides a reference for similar bridge construction.
2010, 40(10): 31-36,53.
doi: 10.13204/j.gyjz201010008
Abstract:
Fengshi River Bridge,the first highest bridge in Henan,is the largest concrete continuous rigid frame bridge in Henan express way.The superstructure of main span is the pre-stressed concrete continuous rigid frame,and the substructure is rectangular hollow thin wall pier,and the height of the highest pier is 107 m and with 2.2 m wide pile group foundation.The self-lifting platform trap door method was adopted to construct high pier;and the two-T synchronous suspending crane construction method with cantilever concreting was adopted to construct box girder.A field construction quality group was established,which was in charge of the entire process quality safety control and the technical guarantee,such key links as safety,material quality and so on;thus speeding up the construction progress and guaranteeing the project quality and the construction security,and which accumulated important project experience for the structural design and the construction quality control of continuous rigid frame bridges.
Fengshi River Bridge,the first highest bridge in Henan,is the largest concrete continuous rigid frame bridge in Henan express way.The superstructure of main span is the pre-stressed concrete continuous rigid frame,and the substructure is rectangular hollow thin wall pier,and the height of the highest pier is 107 m and with 2.2 m wide pile group foundation.The self-lifting platform trap door method was adopted to construct high pier;and the two-T synchronous suspending crane construction method with cantilever concreting was adopted to construct box girder.A field construction quality group was established,which was in charge of the entire process quality safety control and the technical guarantee,such key links as safety,material quality and so on;thus speeding up the construction progress and guaranteeing the project quality and the construction security,and which accumulated important project experience for the structural design and the construction quality control of continuous rigid frame bridges.
2010, 40(10): 37-40.
doi: 10.13204/j.gyjz201010009
Abstract:
With the advancement in technology and coming of information era,the development of architecture surface is in an unprecedented flourishing situation,characteristics of the skin becomes a direct reflection of architectural features.A softening trend occurs in eco-building skins.The occurrence of this trend is based on science and undergone a rational thought.By borrowing botanical science and hidden building body mass,fuzzy boundaries of architecture and environment;by borrowing physical science to create a complex surface skin,it is softened the interface between the architecture and environment;by borrowing bionics theory,it is simulated biological skin texture,thus reducing the differences in manual architectures and environment.Using perfect ecologic architectural form to promote ecology has gradually become a new creation mode.
With the advancement in technology and coming of information era,the development of architecture surface is in an unprecedented flourishing situation,characteristics of the skin becomes a direct reflection of architectural features.A softening trend occurs in eco-building skins.The occurrence of this trend is based on science and undergone a rational thought.By borrowing botanical science and hidden building body mass,fuzzy boundaries of architecture and environment;by borrowing physical science to create a complex surface skin,it is softened the interface between the architecture and environment;by borrowing bionics theory,it is simulated biological skin texture,thus reducing the differences in manual architectures and environment.Using perfect ecologic architectural form to promote ecology has gradually become a new creation mode.
2010, 40(10): 41-44,5.
doi: 10.13204/j.gyjz201010010
Abstract:
ZEGG is a typical ecovillage founded in 1990s in Germany.The article describes the development of ZEGG ecovillage and the sustainable practices of ecological technology and social-economy based on ecological key values,which manifests the cultural demonstration and ecological renovation,gives inspiration to the current development of ecological.
ZEGG is a typical ecovillage founded in 1990s in Germany.The article describes the development of ZEGG ecovillage and the sustainable practices of ecological technology and social-economy based on ecological key values,which manifests the cultural demonstration and ecological renovation,gives inspiration to the current development of ecological.
2010, 40(10): 45-48.
doi: 10.13204/j.gyjz201010011
Abstract:
This paper introduces six most common construction materials used in Australia-cardboard,clay,concrete,glass,steel and timber to build six experimental ecological houses.These six houses show people how to use advanced ecological technology to design and construct affordable,environmentally sustainable buildings,which is a valuable try in the architecture history of Australia.
This paper introduces six most common construction materials used in Australia-cardboard,clay,concrete,glass,steel and timber to build six experimental ecological houses.These six houses show people how to use advanced ecological technology to design and construct affordable,environmentally sustainable buildings,which is a valuable try in the architecture history of Australia.
2010, 40(10): 49-53.
doi: 10.13204/j.gyjz201010012
Abstract:
Based on a real building which is constructed over No.10 underground railway in Shanghai,the paper investigates the vibration isolating effect of sand layer and the propagation rule of vibration in structure by erecting soil-structure combining plan finite element method model.It shows that sand layer has little contribution to reducing the vibration.Meanwhile by discussing the difference between earthquake and subway vibration,it shows that element size should decided by the excellent frequency of vibration.In the end,farther isolating measures are suggested.
Based on a real building which is constructed over No.10 underground railway in Shanghai,the paper investigates the vibration isolating effect of sand layer and the propagation rule of vibration in structure by erecting soil-structure combining plan finite element method model.It shows that sand layer has little contribution to reducing the vibration.Meanwhile by discussing the difference between earthquake and subway vibration,it shows that element size should decided by the excellent frequency of vibration.In the end,farther isolating measures are suggested.
2010, 40(10): 54-60.
doi: 10.13204/j.gyjz201010013
Abstract:
A 1 /4 scale four-storey model of post-tensioned unbonded prestressed concrete hollow slab-column structure has been made to do the load test in elascity on the four-storey plate before a shaking table vibration and ultimate load test on the second-storey plate after the shaking table vibration.By measuring the floor deflection,stresses of steel bars and crack of hollow slab,the earthquake damage of post-tensioned unbonded prestressed concrete hollow slab-column structure and the bearing capacity of the floor are explored.The test results showed that the middle points deflections of hollow slab and beams in parallel and vertical direction the tubes of are larger after the earthquake than before the earthquake in the same load.The hollow floor has a good integrity,the influence of earthquake on the stiffness of the slab is very smaller.The bearing capacity tests of slab can be also divided into three stages: elastic stage,crack expansion stage and destruction stage.The influence of earthquake on prestressed hidden beams in vertical direction of tube are larger than the those in parallel direction of tube.The mid-span deflections of beams in vertical direction of tube are increased significantly than those in parallel direction of tube after earthquake.Based on the test results and in consideration of crack growth in hollow slab,a improved plastic hinge model is set up to predict the ultimate loads,The calculated results of the ultimate loads with improved plastic hinge model are in good agreement with the experiment data.
A 1 /4 scale four-storey model of post-tensioned unbonded prestressed concrete hollow slab-column structure has been made to do the load test in elascity on the four-storey plate before a shaking table vibration and ultimate load test on the second-storey plate after the shaking table vibration.By measuring the floor deflection,stresses of steel bars and crack of hollow slab,the earthquake damage of post-tensioned unbonded prestressed concrete hollow slab-column structure and the bearing capacity of the floor are explored.The test results showed that the middle points deflections of hollow slab and beams in parallel and vertical direction the tubes of are larger after the earthquake than before the earthquake in the same load.The hollow floor has a good integrity,the influence of earthquake on the stiffness of the slab is very smaller.The bearing capacity tests of slab can be also divided into three stages: elastic stage,crack expansion stage and destruction stage.The influence of earthquake on prestressed hidden beams in vertical direction of tube are larger than the those in parallel direction of tube.The mid-span deflections of beams in vertical direction of tube are increased significantly than those in parallel direction of tube after earthquake.Based on the test results and in consideration of crack growth in hollow slab,a improved plastic hinge model is set up to predict the ultimate loads,The calculated results of the ultimate loads with improved plastic hinge model are in good agreement with the experiment data.
2010, 40(10): 61-64.
doi: 10.13204/j.gyjz201010014
Abstract:
Inclined cracks on the top of masonry walls are always the important issue troubling designers and constructors.Previous studies hold that the cause of the cracks is temperature variation and differential settlement of foundation and so on.From the angle of different vertical compression,this paper presents a numerical analysis of masonry wall bearing different vertical load by finite element method.The fracture distribution and morphological characteristics of cracks have good agreement with theoretical analysis and test results.The simulated results show that the theory of different vertical compression is correct and the feasibility of FEM method is validated.Masonry with construction measures has been compared with that without construction measures in order to investigate effective method to this type of cracks.
Inclined cracks on the top of masonry walls are always the important issue troubling designers and constructors.Previous studies hold that the cause of the cracks is temperature variation and differential settlement of foundation and so on.From the angle of different vertical compression,this paper presents a numerical analysis of masonry wall bearing different vertical load by finite element method.The fracture distribution and morphological characteristics of cracks have good agreement with theoretical analysis and test results.The simulated results show that the theory of different vertical compression is correct and the feasibility of FEM method is validated.Masonry with construction measures has been compared with that without construction measures in order to investigate effective method to this type of cracks.
2010, 40(10): 65-70.
doi: 10.13204/j.gyjz201010015
Abstract:
It is studied the temperature stress of an overlength basement concrete structure in Shenyang by finite computing software.It is also explored the characteristics of temperature stress of the base board,floor and exterior wall with and without the post-pouring strengthening band.And four schemes are put forward to control the temperature stress of the second construction stage.The results show that the temperature stress of the basement with the post-pouring strengthening band according to the schemg decreases obviously.The conclusion shows that expansion joint may not be set on the overlength basement through setting the post-pouring strengthening band and temperature shrink reinforce ment reasonably,adopting the shrinkage-compensating concrete,adopting the fourth scheme to control the second construction stage,along with doing a good job in temperature difference,materials,production technology of concrete and construction.
It is studied the temperature stress of an overlength basement concrete structure in Shenyang by finite computing software.It is also explored the characteristics of temperature stress of the base board,floor and exterior wall with and without the post-pouring strengthening band.And four schemes are put forward to control the temperature stress of the second construction stage.The results show that the temperature stress of the basement with the post-pouring strengthening band according to the schemg decreases obviously.The conclusion shows that expansion joint may not be set on the overlength basement through setting the post-pouring strengthening band and temperature shrink reinforce ment reasonably,adopting the shrinkage-compensating concrete,adopting the fourth scheme to control the second construction stage,along with doing a good job in temperature difference,materials,production technology of concrete and construction.
2010, 40(10): 71-75.
doi: 10.13204/j.gyjz201010016
Abstract:
This paper comparatively analyzed the instant loss of post-tensioned prestressed frame beams by using embedded metal corrugated pipe and corrugated plastic pipe from the view of design.Then a site experimental study of post-tensioned prestressed frame beams by using corrugated plastic pipe was carried out to monitor the friction loss,anchorage loss,inverted arch and strain during tensioning process.The coefficient of deviation k and the coefficient of conduit friction were regressed.The theoretical and experimental values of friction loss and anchorage loss were compared.The research result shows parameters = 0.001 5 and = 0.15 adopted in the design are close to experimental value.
This paper comparatively analyzed the instant loss of post-tensioned prestressed frame beams by using embedded metal corrugated pipe and corrugated plastic pipe from the view of design.Then a site experimental study of post-tensioned prestressed frame beams by using corrugated plastic pipe was carried out to monitor the friction loss,anchorage loss,inverted arch and strain during tensioning process.The coefficient of deviation k and the coefficient of conduit friction were regressed.The theoretical and experimental values of friction loss and anchorage loss were compared.The research result shows parameters = 0.001 5 and = 0.15 adopted in the design are close to experimental value.
2010, 40(10): 76-81.
doi: 10.13204/j.gyjz201010017
Abstract:
Suction caisson foundations for offshore wind turbines are subjected to vertical,horizontal and torsional loads,which are induced by self-weight of structures and offshore environment.This loading condition is referred to as combined loading mode.In this paper,the results of numerical study on the bearing capacity of suction caisson installed in homogeneous clayey soil to support wind turbine structures were presented,considering the frictional contact behavior of interface between skirt and subsoil.Suction caisson with aspect ratios of 0.25 ～ 1.0 and eccentricity ratios of horizontal loads varying in the range of 0.0 ～ 2.0 was considered.The bearing capacity behavior of the caisson under pure vertical,lateral,torsional loads was investigated through displacement controlled method first,followed by the interaction of these loads with each other by using load-displacement controlled analysis method.The interaction of various combinations of loading was presented in the form of failure locus.It is shown that the vertical capacity from FE analysis agrees well with that of modified conventional method,and horizontal capacity factor decreases with aspect ratio increasing.The torsional load has significant effect on the vertical capacity but has less effect on the horizontal capacity.The normalized failure loci for suction caisson with different eccentricity ratio can be fitted by elliptic curve.
Suction caisson foundations for offshore wind turbines are subjected to vertical,horizontal and torsional loads,which are induced by self-weight of structures and offshore environment.This loading condition is referred to as combined loading mode.In this paper,the results of numerical study on the bearing capacity of suction caisson installed in homogeneous clayey soil to support wind turbine structures were presented,considering the frictional contact behavior of interface between skirt and subsoil.Suction caisson with aspect ratios of 0.25 ～ 1.0 and eccentricity ratios of horizontal loads varying in the range of 0.0 ～ 2.0 was considered.The bearing capacity behavior of the caisson under pure vertical,lateral,torsional loads was investigated through displacement controlled method first,followed by the interaction of these loads with each other by using load-displacement controlled analysis method.The interaction of various combinations of loading was presented in the form of failure locus.It is shown that the vertical capacity from FE analysis agrees well with that of modified conventional method,and horizontal capacity factor decreases with aspect ratio increasing.The torsional load has significant effect on the vertical capacity but has less effect on the horizontal capacity.The normalized failure loci for suction caisson with different eccentricity ratio can be fitted by elliptic curve.
2010, 40(10): 82-85.
doi: 10.13204/j.gyjz201010018
Abstract:
Foundation differential settlement is the main factor affecting longitudinal mechanical properties of the buried culvert.The more reasonable longitudinal mechanical model of underground culvert was established based on Pasternak foundation model considering the defect of Winkler foundation model.The deflection curve of culvert was derived and longitudinal mechanical properties were analyzed.The research shows that the deflection,rotation,bending moment and shear force of the culvert are mutated in the differential settlement region and the impact of differential settlement is limited.
Foundation differential settlement is the main factor affecting longitudinal mechanical properties of the buried culvert.The more reasonable longitudinal mechanical model of underground culvert was established based on Pasternak foundation model considering the defect of Winkler foundation model.The deflection curve of culvert was derived and longitudinal mechanical properties were analyzed.The research shows that the deflection,rotation,bending moment and shear force of the culvert are mutated in the differential settlement region and the impact of differential settlement is limited.
2010, 40(10): 86-90.
doi: 10.13204/j.gyjz201010019
Abstract:
Three negative pressure distribution modesline mode,parabola mode and exponent mode were respectively applied in the vertical drainage channels of the vacuum preloading test section of Beijing-Shanghai High-Speed Railway under identical conditions.Finite element simulation was made in calculation of the consolidation process of roadbed.The calculation results were compared with measured data.Differences of calculation results were found with the above mentioned three distribution modes.Reasons causing the differences between calculation results and measured data of the three distribution modes were analyzed.Analysis results show that,it is not very rational that negative pressure linearity-decrease from one value to zero or the other value along up-to-down vertical drainage channels.This will cause too much difference between calculation results and measured values.The negative pressure distribution mode of exponent type is commended to apply in silts.But the negative pressure distribution mode of line type is available to the vertical drainage channels in crust up silt.
Three negative pressure distribution modesline mode,parabola mode and exponent mode were respectively applied in the vertical drainage channels of the vacuum preloading test section of Beijing-Shanghai High-Speed Railway under identical conditions.Finite element simulation was made in calculation of the consolidation process of roadbed.The calculation results were compared with measured data.Differences of calculation results were found with the above mentioned three distribution modes.Reasons causing the differences between calculation results and measured data of the three distribution modes were analyzed.Analysis results show that,it is not very rational that negative pressure linearity-decrease from one value to zero or the other value along up-to-down vertical drainage channels.This will cause too much difference between calculation results and measured values.The negative pressure distribution mode of exponent type is commended to apply in silts.But the negative pressure distribution mode of line type is available to the vertical drainage channels in crust up silt.
2010, 40(10): 91-94.
doi: 10.13204/j.gyjz201010020
Abstract:
Using the combination of static load test and numerical calculation,the effects of pile parameters such as the stress distribution of soil surrounding a pile,helical width and helical pitch etc on the bearing behavior of a bored screw pile were analyzed,whose influencing laws were obtained,thus optimizing the design parameters of this sort of pile.Through a comparison of project cost,the cost of a screw pile is much lower than that of normal one under same bearing capacity.
Using the combination of static load test and numerical calculation,the effects of pile parameters such as the stress distribution of soil surrounding a pile,helical width and helical pitch etc on the bearing behavior of a bored screw pile were analyzed,whose influencing laws were obtained,thus optimizing the design parameters of this sort of pile.Through a comparison of project cost,the cost of a screw pile is much lower than that of normal one under same bearing capacity.
2010, 40(10): 95-97,139.
doi: 10.13204/j.gyjz201010021
Abstract:
The size effect of concrete strength is influenced by its brittleness.Therefore,there is an inherent relation between them.However,the impact of the brittleness varies from different strength.With the experimental study on the compressive strength of high and super-high concrete,it is explored the law of the correlation between brittleness and compressive strength.The results show that compressive strength of concrete is not sure to be affected by brittleness directly,but it will be done due to the actual change in the concrete binding conditions.
The size effect of concrete strength is influenced by its brittleness.Therefore,there is an inherent relation between them.However,the impact of the brittleness varies from different strength.With the experimental study on the compressive strength of high and super-high concrete,it is explored the law of the correlation between brittleness and compressive strength.The results show that compressive strength of concrete is not sure to be affected by brittleness directly,but it will be done due to the actual change in the concrete binding conditions.
2010, 40(10): 98-102.
doi: 10.13204/j.gyjz201010022
Abstract:
For the CFRP tendons being better applied to the rock bolt anchor,three-wire 7CFRP bar pressure-type anchor specimens were made.Through field tests it was analyzed theoretically the ultimate bearing capacity of anchor,displacement of the anchor head and the anchorage boby strain,by which it was formed a set of procedures of fabriction and construction of pressure-type CFRP tendon anchor.
For the CFRP tendons being better applied to the rock bolt anchor,three-wire 7CFRP bar pressure-type anchor specimens were made.Through field tests it was analyzed theoretically the ultimate bearing capacity of anchor,displacement of the anchor head and the anchorage boby strain,by which it was formed a set of procedures of fabriction and construction of pressure-type CFRP tendon anchor.
2010, 40(10): 103-105,110.
doi: 10.13204/j.gyjz201010023
Abstract:
The concrete strengthened was placed in the natural,water,acid,alkaline and carbonation environments for 14 d and 56 d.Effect of erosion medium on adhesive property between the concrete strengthened and CFRP was researched by measuring the normal tensile strength and observing the destructional forms between concrete and CFRP.The results showed that the normal tensile strength was obviously reduced by acid environment and followed by carbonation environment,alkaline environment,water environment after 14 d.The tensile strength was also obviously reduced by acid environment and followed by alkaline environment,water environment after 56 d.Carbonationt environmen increased the novmal tensile strength between the concrete strengthened and CFRP.After 14 d destructional forms of the concrete strengthened with CFRP only in the acid environment was the bond failure between concrete and CFRP;and under natural and carbonation environments concrete was damaged due to tension stress.This illustrated that acid environment greatly affected the adhesive property between concrete and CFRP.After 56 d destructional form of the concrete in water,acid,and alkaline environments was the bond failure between concrete and CFRP and under other environments concrete was damaged as a result of normal tension stress。This showed that erosion environment more and more greatly affected the adhesive property between concrete and CFRP with increase of ersion time.
The concrete strengthened was placed in the natural,water,acid,alkaline and carbonation environments for 14 d and 56 d.Effect of erosion medium on adhesive property between the concrete strengthened and CFRP was researched by measuring the normal tensile strength and observing the destructional forms between concrete and CFRP.The results showed that the normal tensile strength was obviously reduced by acid environment and followed by carbonation environment,alkaline environment,water environment after 14 d.The tensile strength was also obviously reduced by acid environment and followed by alkaline environment,water environment after 56 d.Carbonationt environmen increased the novmal tensile strength between the concrete strengthened and CFRP.After 14 d destructional forms of the concrete strengthened with CFRP only in the acid environment was the bond failure between concrete and CFRP;and under natural and carbonation environments concrete was damaged due to tension stress.This illustrated that acid environment greatly affected the adhesive property between concrete and CFRP.After 56 d destructional form of the concrete in water,acid,and alkaline environments was the bond failure between concrete and CFRP and under other environments concrete was damaged as a result of normal tension stress。This showed that erosion environment more and more greatly affected the adhesive property between concrete and CFRP with increase of ersion time.
2010, 40(10): 106-110.
doi: 10.13204/j.gyjz201010024
Abstract:
Hot-rolled ribbed bars of fine grains are a new type of steel bars whose characteristic value of yielding strength is 500 MPa.Based on the test results of 9 concrete beams reinforced by hot-rolled ribbed bars of fine grains under shear,the shear behavior,the shear failure modes and the main factors affecting the shear capacity of the beams are analyzed.The results show that the shear behavior of concrete beams reinforced by the hot-rolled ribbed bars of fine grains are almost the same as the beams reinforced by common low alloy-steel hot-rolled ribbed bars,the shear bearing capacity of the beams can be calculated by the formulas in curent Code for design of concrete structures(GB50010),and the design value of tensile strength of stirrups for the new ribbed steel bars can be taken as fyv = 360 MPa,the calculated results are in safe side.This proposal may be as a reference for the applications of hot rolled ribbed bars of fine grains in projects.
Hot-rolled ribbed bars of fine grains are a new type of steel bars whose characteristic value of yielding strength is 500 MPa.Based on the test results of 9 concrete beams reinforced by hot-rolled ribbed bars of fine grains under shear,the shear behavior,the shear failure modes and the main factors affecting the shear capacity of the beams are analyzed.The results show that the shear behavior of concrete beams reinforced by the hot-rolled ribbed bars of fine grains are almost the same as the beams reinforced by common low alloy-steel hot-rolled ribbed bars,the shear bearing capacity of the beams can be calculated by the formulas in curent Code for design of concrete structures(GB50010),and the design value of tensile strength of stirrups for the new ribbed steel bars can be taken as fyv = 360 MPa,the calculated results are in safe side.This proposal may be as a reference for the applications of hot rolled ribbed bars of fine grains in projects.
2010, 40(10): 111-116,90.
doi: 10.13204/j.gyjz201010025
Abstract:
In order to study the mechanical properties of four-point-supported glass panels under cyclic load,failure tests are conducted on eleven tempered glass panels with protuberant connectors under the distributed uniform lateral pressure.It is measured the changes in dynamic and static stresses at key points of the glass panels under full cyclic load.The experiments show that the load-stress curves of point-supported tempered glass panels approached to be linear under cyclic load,and the stress of the panels varied slightly with the increase of cycle number.The failure of tempered glass panels is of high brittle fracture.
In order to study the mechanical properties of four-point-supported glass panels under cyclic load,failure tests are conducted on eleven tempered glass panels with protuberant connectors under the distributed uniform lateral pressure.It is measured the changes in dynamic and static stresses at key points of the glass panels under full cyclic load.The experiments show that the load-stress curves of point-supported tempered glass panels approached to be linear under cyclic load,and the stress of the panels varied slightly with the increase of cycle number.The failure of tempered glass panels is of high brittle fracture.
2010, 40(10): 117-121,143.
doi: 10.13204/j.gyjz201010026
Abstract:
Based on the experiments of joint with exterior diaphragms between concrete-filled square steel tubular column and steel beam under cyclic loading,with appropriate material stress-strain relations and failure criteria,the mechanical properties of this type of joint were researched by using ANSYS,finite element analyses were conducted under cyclic loading,the hysteretic and framework curves of this type joint between test and theoretical were researched.The study results showed that all specimens have good ductility and energy dissipation capacity.The story angle drift ductility ratios are = 3.07 ～ 3.66,the elastic and elastic-plastic story angle drift are y = 0.004 1 ～ 0.004 7 and u = 0.012 4 ～ 0.017 2,and the equivalent viscous damping coefficients are he = 0.26 ～ 0.35,which meet the needs of the current code for seismic design of building.
Based on the experiments of joint with exterior diaphragms between concrete-filled square steel tubular column and steel beam under cyclic loading,with appropriate material stress-strain relations and failure criteria,the mechanical properties of this type of joint were researched by using ANSYS,finite element analyses were conducted under cyclic loading,the hysteretic and framework curves of this type joint between test and theoretical were researched.The study results showed that all specimens have good ductility and energy dissipation capacity.The story angle drift ductility ratios are = 3.07 ～ 3.66,the elastic and elastic-plastic story angle drift are y = 0.004 1 ～ 0.004 7 and u = 0.012 4 ～ 0.017 2,and the equivalent viscous damping coefficients are he = 0.26 ～ 0.35,which meet the needs of the current code for seismic design of building.
2010, 40(10): 122-125.
doi: 10.13204/j.gyjz201010027
Abstract:
Unequal thickness walled rectangular concrete-filled steel tubes(CFT) are a sort of optimization design for rectangular CFT as beams.It is derived a theoretic formula for calculating the ultimate strength of unequal-thickness walled rectangular CFT members subjected to pure bending based on relevant theoretical assumptions.the correctness of the theoretical formula is demonstrated by the degenerated analysis.The results obtained by the formula agree well with those of the experiments.Which are in the permitted scope of projects.
Unequal thickness walled rectangular concrete-filled steel tubes(CFT) are a sort of optimization design for rectangular CFT as beams.It is derived a theoretic formula for calculating the ultimate strength of unequal-thickness walled rectangular CFT members subjected to pure bending based on relevant theoretical assumptions.the correctness of the theoretical formula is demonstrated by the degenerated analysis.The results obtained by the formula agree well with those of the experiments.Which are in the permitted scope of projects.
2010, 40(10): 126-131.
doi: 10.13204/j.gyjz201010028
Abstract:
Stiffness coefficient describing the rigidity of end-plate connection is defined based on the formula that was obtained by component method to calculate the initial stiffness of end-plate joint.A simplified expression for the initial stiffness is then deduced taking stiffness coefficient as main variable.By parameter analysis for the initial stiffness of end-plate joints in slender steel frames,the expressions of stiffness coefficient under different joint constructions are fitted.Accordingly,stiffness coefficient method to calculate the initial stiffness is developed.The method behaves with enough accuracy as compared with the results of tests and finite element analysis.So does the short-cut methods which is derived at the same time.
Stiffness coefficient describing the rigidity of end-plate connection is defined based on the formula that was obtained by component method to calculate the initial stiffness of end-plate joint.A simplified expression for the initial stiffness is then deduced taking stiffness coefficient as main variable.By parameter analysis for the initial stiffness of end-plate joints in slender steel frames,the expressions of stiffness coefficient under different joint constructions are fitted.Accordingly,stiffness coefficient method to calculate the initial stiffness is developed.The method behaves with enough accuracy as compared with the results of tests and finite element analysis.So does the short-cut methods which is derived at the same time.
2010, 40(10): 132-135.
doi: 10.13204/j.gyjz201010029
Abstract:
Separating from the construction,the surface which is one kind of form between functional space and elevation form,is the esternal performance of the formal logic.The design of Jingrui Plaza in Baoshan District of Shanghai repackages the elevation.The operation pattem of the project,which is meaningful to the real operation,urges the architect to crmbine the theoretical thinking of function,elevation and surface with the design practice.
Separating from the construction,the surface which is one kind of form between functional space and elevation form,is the esternal performance of the formal logic.The design of Jingrui Plaza in Baoshan District of Shanghai repackages the elevation.The operation pattem of the project,which is meaningful to the real operation,urges the architect to crmbine the theoretical thinking of function,elevation and surface with the design practice.
2010, 40(10): 136-139.
doi: 10.13204/j.gyjz201010030
Abstract:
Since 1990,B + H architects have designed a lot of excellent regional buildings such as Xiamen International Convention and Exhibition Center,the Terminal Building of Xiamen Gaoqi International Airport and Xiamen National Accounting Institute,ect.The paper chooses nature,culture and technology as three wedging points to develop how the B + H dealing with the relationship between the contemporary architecture and the regional characteristics to create the environment with high quality.
Since 1990,B + H architects have designed a lot of excellent regional buildings such as Xiamen International Convention and Exhibition Center,the Terminal Building of Xiamen Gaoqi International Airport and Xiamen National Accounting Institute,ect.The paper chooses nature,culture and technology as three wedging points to develop how the B + H dealing with the relationship between the contemporary architecture and the regional characteristics to create the environment with high quality.
2010, 40(10): 140-143.
doi: 10.13204/j.gyjz201010031
Abstract:
Through the suitability of industrial heritage,strengthen industrial heritage protection and found its potential value space,advance new urban spatial form with perfect reconstruction,and the construction of community development and prosperity of the region,and is currently in the process of urban renewal important issues.Based on the transformation of scientific and urban industrial heritage,outstanding case of urban industrial heritage communitization transformation implementation countermeasure.
Through the suitability of industrial heritage,strengthen industrial heritage protection and found its potential value space,advance new urban spatial form with perfect reconstruction,and the construction of community development and prosperity of the region,and is currently in the process of urban renewal important issues.Based on the transformation of scientific and urban industrial heritage,outstanding case of urban industrial heritage communitization transformation implementation countermeasure.
