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2010 Vol. 40, No. 2
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2010, 40(2): 1-6.
doi: 10.13204/j.gyjz201002001
Abstract:
National standard of tall falsework has been not officially promulgated at present,and there is not an unified standard in design and construction of a tall falsework,which causes tall falsework to collapse sometimes.It is analyzed that the present conditions of the definition of tall falsework,load combination,calculation model,study on test,semi-rigid joint,initial defects and degree of reliability of system etc.And further the ideas of research on the tall falsework are rationalized.It is proposed a series of problems that must be solved urgently,which points out the direction of follow-up researches on this subject and lays the foundation for compiling relevant specifications.
National standard of tall falsework has been not officially promulgated at present,and there is not an unified standard in design and construction of a tall falsework,which causes tall falsework to collapse sometimes.It is analyzed that the present conditions of the definition of tall falsework,load combination,calculation model,study on test,semi-rigid joint,initial defects and degree of reliability of system etc.And further the ideas of research on the tall falsework are rationalized.It is proposed a series of problems that must be solved urgently,which points out the direction of follow-up researches on this subject and lays the foundation for compiling relevant specifications.
2010, 40(2): 7-11.
doi: 10.13204/j.gyjz201002002
Abstract:
The stability bearing capacity of a coupler steel tube falsework is affected by tectonic factors.Through the establishment of the three-dimensional finite element model of falsework,it is explored that effects of longitudinal and lateral distances,the falsework bracket puts up height,sweeping bar,the length of the top horizontal bar extending from top(value of a),bridging and other structural factors of the falsework on the stability of the frame system,and then the formula for calculating height adjustment factor is also given.It is proposed the falsework bracket height from the ground can not be more than 0.4 m and bridging should be set up for the falsework.It is recommended a level bridging is set for every 4 steps and a vertical bridging is set for every 4 spans.The length(value of a) of the vertical bar extending from the top horizontal bar should not be greater than 0.2 m when setting up a falsework.The conclusions of the paper can provide a reference for personnel of design,construction and research.
The stability bearing capacity of a coupler steel tube falsework is affected by tectonic factors.Through the establishment of the three-dimensional finite element model of falsework,it is explored that effects of longitudinal and lateral distances,the falsework bracket puts up height,sweeping bar,the length of the top horizontal bar extending from top(value of a),bridging and other structural factors of the falsework on the stability of the frame system,and then the formula for calculating height adjustment factor is also given.It is proposed the falsework bracket height from the ground can not be more than 0.4 m and bridging should be set up for the falsework.It is recommended a level bridging is set for every 4 steps and a vertical bridging is set for every 4 spans.The length(value of a) of the vertical bar extending from the top horizontal bar should not be greater than 0.2 m when setting up a falsework.The conclusions of the paper can provide a reference for personnel of design,construction and research.
2010, 40(2): 12-16.
doi: 10.13204/j.gyjz201002003
Abstract:
On the basis of the studies on coupler steel tube falsework by previous researches model is set up by investigating the spot and making use of finite element analysis software,and it analyses the mechanism deeply that how the constitution factors effect the stability bearing capacity of the falsework.The constitution factors include longitudinal distance,lateral distance,step length,height of the floor members,length of upright bars extruding from top and etc.And on this basis,a relational expression of stability bearing capacity and factors is also established.Considering the geometric variation of the factors and the randomness of the initial defects at the same time,it is deduced the reduction factor of the stability bearing capacity of the falsework.The calculation formula of the actual stability bearing capacity is obtained,which can supply a reliable basis for scheme design and safety analysis of the coupler tall falsework.
On the basis of the studies on coupler steel tube falsework by previous researches model is set up by investigating the spot and making use of finite element analysis software,and it analyses the mechanism deeply that how the constitution factors effect the stability bearing capacity of the falsework.The constitution factors include longitudinal distance,lateral distance,step length,height of the floor members,length of upright bars extruding from top and etc.And on this basis,a relational expression of stability bearing capacity and factors is also established.Considering the geometric variation of the factors and the randomness of the initial defects at the same time,it is deduced the reduction factor of the stability bearing capacity of the falsework.The calculation formula of the actual stability bearing capacity is obtained,which can supply a reliable basis for scheme design and safety analysis of the coupler tall falsework.
2010, 40(2): 17-19,27.
doi: 10.13204/j.gyjz201002004
Abstract:
Based on the study on ultimate strength test of full-size falsework in 5 different operating conditions,and by the introduction of a stable bearing capacity test of the falsework,a three-dimensional finite element model is set up,with which the effect of generalized initial imperfections on the structural stability can be analyzed more accurately.It is further shown through on-site testing that the geometric imperfections of the partially-braced frame column may be replaced by the equivalent notional lateral load.Moreover,generalized equivalent notional lateral loads participate in all of the load combination.
Based on the study on ultimate strength test of full-size falsework in 5 different operating conditions,and by the introduction of a stable bearing capacity test of the falsework,a three-dimensional finite element model is set up,with which the effect of generalized initial imperfections on the structural stability can be analyzed more accurately.It is further shown through on-site testing that the geometric imperfections of the partially-braced frame column may be replaced by the equivalent notional lateral load.Moreover,generalized equivalent notional lateral loads participate in all of the load combination.
2010, 40(2): 20-23.
doi: 10.13204/j.gyjz201002005
Abstract:
Based on the semi-rigid joint experiment,it was gained the formula of initial torsion stiffness R_k and bolt tightening moment T of right-angle coupler.On the basis of considering semi-rigid joint,it is indicated that it is rational to use imaginary horizontal force of 0.1% stability capacity in every joint to simulate initial imperfections of the frame by finite element software.Combining with the contrast of finite element analysis results and experimental results,it is the prerequisite to calculate stability capacity exactly with semi-rigid joint of falsework considered.At the same time,the descending trend of stability capacity of the falsework was evident when tightening torques of the couplers is less than 30 Nm.Therefore,during the construction process,it is indispensable to sampling inspections of the tightening torques of the couplers strictly.
Based on the semi-rigid joint experiment,it was gained the formula of initial torsion stiffness R_k and bolt tightening moment T of right-angle coupler.On the basis of considering semi-rigid joint,it is indicated that it is rational to use imaginary horizontal force of 0.1% stability capacity in every joint to simulate initial imperfections of the frame by finite element software.Combining with the contrast of finite element analysis results and experimental results,it is the prerequisite to calculate stability capacity exactly with semi-rigid joint of falsework considered.At the same time,the descending trend of stability capacity of the falsework was evident when tightening torques of the couplers is less than 30 Nm.Therefore,during the construction process,it is indispensable to sampling inspections of the tightening torques of the couplers strictly.
2010, 40(2): 24-27.
doi: 10.13204/j.gyjz201002006
Abstract:
This paper studied the torsional rigidity of couplers for right angle intersection members of falsework,which were characterized by semi-rigid joint.It was showed that initial torsion stiffness R_k and two parameters(M-) logarithmic nonlinear model of falsework joints was obtained,whose bolt tightening torque T=40 Nm.The proposed coefficient for effective length of falsework should consider semi-rigid joint with the calculation based on sway frame theory and then be compared with coefficient for effective length given by the stability carrying capacity test of the overall falsework.The results show that design falsework according to the semi-rigid joint with sway frame theory is safe and reasonable.Which provides a theoretical basis for formulating relevant specifications(rules).
This paper studied the torsional rigidity of couplers for right angle intersection members of falsework,which were characterized by semi-rigid joint.It was showed that initial torsion stiffness R_k and two parameters(M-) logarithmic nonlinear model of falsework joints was obtained,whose bolt tightening torque T=40 Nm.The proposed coefficient for effective length of falsework should consider semi-rigid joint with the calculation based on sway frame theory and then be compared with coefficient for effective length given by the stability carrying capacity test of the overall falsework.The results show that design falsework according to the semi-rigid joint with sway frame theory is safe and reasonable.Which provides a theoretical basis for formulating relevant specifications(rules).
2010, 40(2): 28-31.
doi: 10.13204/j.gyjz201002007
Abstract:
To study mechanical properties of coupler steel pipe falsework,it was conducted a series of full-scale researches on the spatial structure of the falsework,and it was obtained that the ultimate bearing capacity of the falsework under different conditions,the destruction pattern and the load-displacement curve of the top-level node.It can be seen that in the 5 working conditions,the working condition 1 without cross bridging causes its supporting capacity to be the smallest;a reduction of step pitch,makes the bearing capacity of condition 4 increase by 13.8% as compared with working condition 3,but the reduction of the horizontal distance makes stability of working condition 5 enhance by 3% than that of working condition 4.Instability of the falsework belongs to the overall instability,the arrangement of the bridging to the support has an important influence to its instability mode,in the following researches,it still need to determine the standard structure of the falsework and then carries out a series of experiments and the fundamental researches on it.The falsework belongs to the steel structure category,it is suggested that when designing and calculating,the sway frames theory should be used and the semi-rigid node should be considered.
To study mechanical properties of coupler steel pipe falsework,it was conducted a series of full-scale researches on the spatial structure of the falsework,and it was obtained that the ultimate bearing capacity of the falsework under different conditions,the destruction pattern and the load-displacement curve of the top-level node.It can be seen that in the 5 working conditions,the working condition 1 without cross bridging causes its supporting capacity to be the smallest;a reduction of step pitch,makes the bearing capacity of condition 4 increase by 13.8% as compared with working condition 3,but the reduction of the horizontal distance makes stability of working condition 5 enhance by 3% than that of working condition 4.Instability of the falsework belongs to the overall instability,the arrangement of the bridging to the support has an important influence to its instability mode,in the following researches,it still need to determine the standard structure of the falsework and then carries out a series of experiments and the fundamental researches on it.The falsework belongs to the steel structure category,it is suggested that when designing and calculating,the sway frames theory should be used and the semi-rigid node should be considered.
2010, 40(2): 32-35.
doi: 10.13204/j.gyjz201002008
Abstract:
According to the tracking and monitoring of all course loading of specimens under 5 conditions,it is analysed distortion characteristic of integral frame and local vertical bars.The results show that the support have obvious lateral displacement of double direction,the distortion curve of the vertical bar is mainly b kind that is controled by nodal displacement,so the coupler steel tube falsework should be a frame with lateral displacement and semi-rigid node.In addition,a bridging has a good restriction on torsion and distortion of the falsework special attention should be given to its disposal in constructing.Distortion characteristic of the falsework bears important referrence value on founding theory of analyzing frame stability.
According to the tracking and monitoring of all course loading of specimens under 5 conditions,it is analysed distortion characteristic of integral frame and local vertical bars.The results show that the support have obvious lateral displacement of double direction,the distortion curve of the vertical bar is mainly b kind that is controled by nodal displacement,so the coupler steel tube falsework should be a frame with lateral displacement and semi-rigid node.In addition,a bridging has a good restriction on torsion and distortion of the falsework special attention should be given to its disposal in constructing.Distortion characteristic of the falsework bears important referrence value on founding theory of analyzing frame stability.
2010, 40(2): 36-41.
doi: 10.13204/j.gyjz201002009
Abstract:
Using the method of integration hand loading with electrical measurement,it was done a tracking record of the whole model's structural instability and stress change in the structural factors of the coupler steel tube falsework.And then the paper detailedly analysed the forced property of the horizontal pole and the bridging and mutual influence between them.The results show that the stress of the pole becomes less when bridging gets stronger and is significantly less than the bridging stress;and bridging can effectively reduce the internal force uneven distribution of the pole.According to the actual situation of construction, the paper puts forward relevant setting standard of the bridging,which can provide a reference for designers and constructors.
Using the method of integration hand loading with electrical measurement,it was done a tracking record of the whole model's structural instability and stress change in the structural factors of the coupler steel tube falsework.And then the paper detailedly analysed the forced property of the horizontal pole and the bridging and mutual influence between them.The results show that the stress of the pole becomes less when bridging gets stronger and is significantly less than the bridging stress;and bridging can effectively reduce the internal force uneven distribution of the pole.According to the actual situation of construction, the paper puts forward relevant setting standard of the bridging,which can provide a reference for designers and constructors.
2010, 40(2): 42-46.
doi: 10.13204/j.gyjz201002010
Abstract:
In this paper,a survey on loads of supporting structure for tall and large falsework during construction has been conducted.It is found that the deadweight of new-cast concrete obeying normal distribution.Although there is fluctuation in the average value and coefficient of variation of deadweight of new-cast concrete,its overall trend is ever-reduced and becomes stable;the distribution of construction personnel and equipment load obeying skew distribution and has the basic characteristics of exponential distribution.The exponential distribution can describe loads of supporting structure for tall and large falsework during construction.Referring the method of choosing the standard value of loads in service phase,the standard value of loads of supporting structure for tall and large falsework during construction is suggested.According to tracking and monitoring the force of supporting structure for tall and large falsework of typical projects during construction,it can verify the correctness of recommended values of loads.The results can be used for design and safety control of supporting structure for tall and large falsework,and provide a reliable basis for formulation and revision of the relevant norms.
In this paper,a survey on loads of supporting structure for tall and large falsework during construction has been conducted.It is found that the deadweight of new-cast concrete obeying normal distribution.Although there is fluctuation in the average value and coefficient of variation of deadweight of new-cast concrete,its overall trend is ever-reduced and becomes stable;the distribution of construction personnel and equipment load obeying skew distribution and has the basic characteristics of exponential distribution.The exponential distribution can describe loads of supporting structure for tall and large falsework during construction.Referring the method of choosing the standard value of loads in service phase,the standard value of loads of supporting structure for tall and large falsework during construction is suggested.According to tracking and monitoring the force of supporting structure for tall and large falsework of typical projects during construction,it can verify the correctness of recommended values of loads.The results can be used for design and safety control of supporting structure for tall and large falsework,and provide a reliable basis for formulation and revision of the relevant norms.
2010, 40(2): 47-50,54.
doi: 10.13204/j.gyjz201002011
Abstract:
Generally,a coupler steel tube falsework just bears the vertical loads,however,in some structure construction,the falsework should carry a horizontal load from lateral concrete pouring.Taking a subway project for example,the stability bearing capacity of the falsework when it bears a double-direction load is calculated,whose result is compare with that of its carrying both two-way load and a horizontal load,so that a parameter from building of falsework is got.The result of a numerical analysis shows that stable bearing capacity of the falsework under double-direction load is lower than its carrying a vertical load only.So,a series of reliable measures are needed to maintain the stability of the whole structure.
Generally,a coupler steel tube falsework just bears the vertical loads,however,in some structure construction,the falsework should carry a horizontal load from lateral concrete pouring.Taking a subway project for example,the stability bearing capacity of the falsework when it bears a double-direction load is calculated,whose result is compare with that of its carrying both two-way load and a horizontal load,so that a parameter from building of falsework is got.The result of a numerical analysis shows that stable bearing capacity of the falsework under double-direction load is lower than its carrying a vertical load only.So,a series of reliable measures are needed to maintain the stability of the whole structure.
2010, 40(2): 116-119.
doi: 10.13204/j.gyjz201002027
Abstract:
Because of high-rise commercial building foundation construction resulting in damage to adjacent building in a city of Jiangsu,through household surveys,on-site testing and a comprehensive analysis of reasoning according to the information of foundation construction and monitoring of foundation pit,it is reproduced the entire process of damage to adjacent building in the foundation construction and reasoning it,and finally repair recommendations on partially damaged building are proposed.
Because of high-rise commercial building foundation construction resulting in damage to adjacent building in a city of Jiangsu,through household surveys,on-site testing and a comprehensive analysis of reasoning according to the information of foundation construction and monitoring of foundation pit,it is reproduced the entire process of damage to adjacent building in the foundation construction and reasoning it,and finally repair recommendations on partially damaged building are proposed.
2010, 40(2): 120-124,96.
doi: 10.13204/j.gyjz201002028
Abstract:
With the research project study on application of external pre-stressed technology for strengthening old bridges under the Railway Ministry as the background,it is conducted the test of bearing capacity of the old concrete board beams,based on the data the same sorts of beams are strengthened by external prestressing technology,on which an evaluation is done.It is further researched and identified the evaluated result by 2 million times of fatigue tests.
With the research project study on application of external pre-stressed technology for strengthening old bridges under the Railway Ministry as the background,it is conducted the test of bearing capacity of the old concrete board beams,based on the data the same sorts of beams are strengthened by external prestressing technology,on which an evaluation is done.It is further researched and identified the evaluated result by 2 million times of fatigue tests.
2010, 40(2): 125-127.
doi: 10.13204/j.gyjz201002029
Abstract:
There were vertical and inclined cracks on the wall of a brick-concrete residential building in Hengyang City.It was showed the building could not meet the prescribed performance in term of strength and serviceability according to the results of identification.The foundation was strengthened and widened with grouting piles and the walls are strengthened with fine aggregate concrete.Satisfactory effect has been obtained after the reinforcement.
There were vertical and inclined cracks on the wall of a brick-concrete residential building in Hengyang City.It was showed the building could not meet the prescribed performance in term of strength and serviceability according to the results of identification.The foundation was strengthened and widened with grouting piles and the walls are strengthened with fine aggregate concrete.Satisfactory effect has been obtained after the reinforcement.
2010, 40(2): 128-131.
doi: 10.13204/j.gyjz201002030
Abstract:
Lots of problematical piles were discovered during inspection of loose core to cement mixing piles,and the piles were in zonal distribution through inspection of excavation.Emergence of the problematical piles was that the red clay was polluted.In this paper,a series of tests of physical and mechanical properties were done by choosing a representative red clay sample of cement mixing piles being polluted in the reinforcement areas.Combining inspection of loose core and excavation,it was discussed influences of the red clay polluted by organic matter on the mechanical property of the cement mixing piles.The research indicates that mechanical softening effects were gradually weakend and the decrease of the indexes of physical and mechanical properties were decreased with the decrease of the distance between cement mixing piles and septic tank.As a result,the problematical piles were in zonal distribution.
Lots of problematical piles were discovered during inspection of loose core to cement mixing piles,and the piles were in zonal distribution through inspection of excavation.Emergence of the problematical piles was that the red clay was polluted.In this paper,a series of tests of physical and mechanical properties were done by choosing a representative red clay sample of cement mixing piles being polluted in the reinforcement areas.Combining inspection of loose core and excavation,it was discussed influences of the red clay polluted by organic matter on the mechanical property of the cement mixing piles.The research indicates that mechanical softening effects were gradually weakend and the decrease of the indexes of physical and mechanical properties were decreased with the decrease of the distance between cement mixing piles and septic tank.As a result,the problematical piles were in zonal distribution.
2010, 40(2): 132-134.
doi: 10.13204/j.gyjz201002031
Abstract:
Based on the design analysis of TCL LCD TV integration manufacturing projects and insights and thinking of the author himself in the process of design,it is expounded some of the architectural design ideas and methods in the new era,and it is expected that some inspiration will be given to the future design,which will make architectural design more mature and perfect.
Based on the design analysis of TCL LCD TV integration manufacturing projects and insights and thinking of the author himself in the process of design,it is expounded some of the architectural design ideas and methods in the new era,and it is expected that some inspiration will be given to the future design,which will make architectural design more mature and perfect.
2010, 40(2): 135-137,127.
doi: 10.13204/j.gyjz201002032
Abstract:
The greatest cross-century science project SSFR is introduced for its integrated application of new technologies in the profiled double-layer metal roof system,whose shape is like a nautilus.Meanwhile,the metal roof system is featured by double-layer,the upper of which is aluminum honeycomb panel while the lower of which is composed of roll-profiled steel sheet and rigid polyurethane foam body.New technologies include waterproof and heat-insulated rigid polyurethane foam system,spiral gutter drainage system and roof connecting system.Moreover,it can provide similar large-scale projects with valuable experiences.
The greatest cross-century science project SSFR is introduced for its integrated application of new technologies in the profiled double-layer metal roof system,whose shape is like a nautilus.Meanwhile,the metal roof system is featured by double-layer,the upper of which is aluminum honeycomb panel while the lower of which is composed of roll-profiled steel sheet and rigid polyurethane foam body.New technologies include waterproof and heat-insulated rigid polyurethane foam system,spiral gutter drainage system and roof connecting system.Moreover,it can provide similar large-scale projects with valuable experiences.
2010, 40(2): 51-54.
doi: 10.13204/j.gyjz201002012
Abstract:
At present,the regeneration of historical industrial field is an important research project in the urban regeneration.From the view of uncertainty,this paper explores this research combined with the regeneration design of area of the National Third Cotton Mill in Zhengzhou.The design resisted massive reconstruction,preserved the previous mill buildings and members;furthermore the collage style and micro-circulation pattern were used,which embodied mutable,dynamic,holistic and stretch design thoughts as well as the design concept of mixed symbiosis and flexible diversification.
At present,the regeneration of historical industrial field is an important research project in the urban regeneration.From the view of uncertainty,this paper explores this research combined with the regeneration design of area of the National Third Cotton Mill in Zhengzhou.The design resisted massive reconstruction,preserved the previous mill buildings and members;furthermore the collage style and micro-circulation pattern were used,which embodied mutable,dynamic,holistic and stretch design thoughts as well as the design concept of mixed symbiosis and flexible diversification.
2010, 40(2): 55-57,91.
doi: 10.13204/j.gyjz201002013
Abstract:
An architecture is that it is not only a practical space constructed by building materials and but also its design implied a certain theme,that is,the construction image.For example,the junk form of Sydney Opera House is a classic form,and water villas are the gems of architectural history.According to the design of China Sea Salt Museum,it is expounded the great charm of an architectural design,which is given by the imagery concept.
An architecture is that it is not only a practical space constructed by building materials and but also its design implied a certain theme,that is,the construction image.For example,the junk form of Sydney Opera House is a classic form,and water villas are the gems of architectural history.According to the design of China Sea Salt Museum,it is expounded the great charm of an architectural design,which is given by the imagery concept.
2010, 40(2): 58-63.
doi: 10.13204/j.gyjz201002014
Abstract:
The paper focuses on obtaining a modified earthquake random model by introducing the structure affecting factor (T) into spectral density function with appropriate consideration of the structural effect on random process of ground motion.Besides,the key parameters in the model are studied in details and calculated by numerical method.The numerical results show that the structure affecting factor,determined by the equaling rules to code spectrum,is clear as a notion of physics and easy for application.In the mean time,the random mean spectrum of SDOF system derived from the modified model are well agreed with the code spectrum.The random model proposed in the paper is of relatively high accuracy and possess broad prospects of application,which will provide random seismic response analysis and dynamic reliable design with dependable references.
The paper focuses on obtaining a modified earthquake random model by introducing the structure affecting factor (T) into spectral density function with appropriate consideration of the structural effect on random process of ground motion.Besides,the key parameters in the model are studied in details and calculated by numerical method.The numerical results show that the structure affecting factor,determined by the equaling rules to code spectrum,is clear as a notion of physics and easy for application.In the mean time,the random mean spectrum of SDOF system derived from the modified model are well agreed with the code spectrum.The random model proposed in the paper is of relatively high accuracy and possess broad prospects of application,which will provide random seismic response analysis and dynamic reliable design with dependable references.
2010, 40(2): 64-68.
doi: 10.13204/j.gyjz201002015
Abstract:
According to the experimental investigation on three specimens of abnormal interior joints under low cyclic reversed loading,the failure process and patterns were obtained.The failure characteristics,mechanical behaviors of abnormal joints such as the load displacement hysteretic loops,rigidity deterioration and energy dissipation were analyzed.The experimental study was conducted that focused on the effect of joint hoop percentage and vertical haunched beam on seismic behaviour of abnormal joints.Test results indicated that joint shear failure process of the specimen was delayed by the application of vertical haunched beam,and the behavior of this new type joint was improved greatly due to the flexural failure formed in the connection between the low beam and the expanded joint core.
According to the experimental investigation on three specimens of abnormal interior joints under low cyclic reversed loading,the failure process and patterns were obtained.The failure characteristics,mechanical behaviors of abnormal joints such as the load displacement hysteretic loops,rigidity deterioration and energy dissipation were analyzed.The experimental study was conducted that focused on the effect of joint hoop percentage and vertical haunched beam on seismic behaviour of abnormal joints.Test results indicated that joint shear failure process of the specimen was delayed by the application of vertical haunched beam,and the behavior of this new type joint was improved greatly due to the flexural failure formed in the connection between the low beam and the expanded joint core.
2010, 40(2): 69-73.
doi: 10.13204/j.gyjz201002016
Abstract:
The forced performances of total-precast concrete frame columns with alveous-connection were investigated under low reverse cyclic loading.The results showed that the forced performances of a total-precast concrete frame column with alveous-connection was equal to the cast-in-suit one.It was concluded that the load transfer path of total-precast concrete frame column with alveous-connection is definite,it could be applied in practice.
The forced performances of total-precast concrete frame columns with alveous-connection were investigated under low reverse cyclic loading.The results showed that the forced performances of a total-precast concrete frame column with alveous-connection was equal to the cast-in-suit one.It was concluded that the load transfer path of total-precast concrete frame column with alveous-connection is definite,it could be applied in practice.
2010, 40(2): 74-76,63.
doi: 10.13204/j.gyjz201002017
Abstract:
The seismic response of Bailin Temple Pagoda was investigated by ANSYS software in this paper.The Solid 65 element and integral continuum model were applied,and stress-strain relationship of masonry structures was defined by the theory of multilinear kinematic hardening(MKIN) while creating the model.The result indicated that the lower floor of pagoda was prone to bring cracks and destroyed owing to larger tension stress,and top of pagoda was destroyed easily owing to excessive displacement.Finally reinforced measures were proposed with the hoop steel or carbon cloth.
The seismic response of Bailin Temple Pagoda was investigated by ANSYS software in this paper.The Solid 65 element and integral continuum model were applied,and stress-strain relationship of masonry structures was defined by the theory of multilinear kinematic hardening(MKIN) while creating the model.The result indicated that the lower floor of pagoda was prone to bring cracks and destroyed owing to larger tension stress,and top of pagoda was destroyed easily owing to excessive displacement.Finally reinforced measures were proposed with the hoop steel or carbon cloth.
2010, 40(2): 77-81.
doi: 10.13204/j.gyjz201002018
Abstract:
Experiments are conducted on novel herringbone braces composite structure under pseudo-dynamic test.A test model of scale 1∶2 is manufactured.The loading process is the input of El Centro wave,and the maximum accelerations of ground motion are respectively small and rare earthquake of 7,8 and 9 intensity.Based on the experiment,the earthquake waves of cracking,yielding and failing for the structure are obtained,they are small earthquake of 8 intensity,rare earthquakes of 7 intensity and 8 intensity.It is obvious that the composite structure posses better ductility and seismic property on the basis of the stiffness deteriorating curve,hysteresis curves and the displacement time curves obtained by the experiment.The vertical displacement of the braces top need not be considered under small earthquakes of 7,8 and 9 intensity,but it need be considered after the braces are attained to yield.
Experiments are conducted on novel herringbone braces composite structure under pseudo-dynamic test.A test model of scale 1∶2 is manufactured.The loading process is the input of El Centro wave,and the maximum accelerations of ground motion are respectively small and rare earthquake of 7,8 and 9 intensity.Based on the experiment,the earthquake waves of cracking,yielding and failing for the structure are obtained,they are small earthquake of 8 intensity,rare earthquakes of 7 intensity and 8 intensity.It is obvious that the composite structure posses better ductility and seismic property on the basis of the stiffness deteriorating curve,hysteresis curves and the displacement time curves obtained by the experiment.The vertical displacement of the braces top need not be considered under small earthquakes of 7,8 and 9 intensity,but it need be considered after the braces are attained to yield.
2010, 40(2): 82-85.
doi: 10.13204/j.gyjz201002019
Abstract:
For several sites with soft soil layer,the difference of site classification between Chinese code GB 500112001 and European code Eurocode 8 is studied in this paper.Firstly,the shear wave velocity of ordinary site,site with soft interlayer within 20 m depth,site with soft soil layer below 20 m depth is computed,and the site classification is classified according to GB 500112001 and Eurocode 8 respectively.Then,the comparative analysis is carried out,it is found that the thickness of soft soil layer is more vulnerable to change site classification of Eurocode 8 than that of GB 500112001 for site with soft interlayer within 20 m depth,which is considered more carefully in Eurocode 8 for site with soft soil layer below 20 m depth.It is suggested that the influence of soft soil layer should be further considered in China code,and the calculation depth should be further extended from 20 m.
For several sites with soft soil layer,the difference of site classification between Chinese code GB 500112001 and European code Eurocode 8 is studied in this paper.Firstly,the shear wave velocity of ordinary site,site with soft interlayer within 20 m depth,site with soft soil layer below 20 m depth is computed,and the site classification is classified according to GB 500112001 and Eurocode 8 respectively.Then,the comparative analysis is carried out,it is found that the thickness of soft soil layer is more vulnerable to change site classification of Eurocode 8 than that of GB 500112001 for site with soft interlayer within 20 m depth,which is considered more carefully in Eurocode 8 for site with soft soil layer below 20 m depth.It is suggested that the influence of soft soil layer should be further considered in China code,and the calculation depth should be further extended from 20 m.
2010, 40(2): 86-91.
doi: 10.13204/j.gyjz201002020
Abstract:
The 3 specimens of blast furnace foundations under the action of vertical load and temperature effect were tested.The influence of temperature on blast furnace foundation is discussed,and the characteristics of foundation stress based on different grounds are compared.The conclusions are: 1)only the top of the foundation is affected by temperature effect;2)under vertical loading,the stress in the bottom of blast furnace foundation supported by uniform ground is low and the stress in the bottom supported by piles is high;3) there is obvious stress concentration at the interface between foudation and the upper sturcture,the way of setting the constructional reinforcement needs improvement.
The 3 specimens of blast furnace foundations under the action of vertical load and temperature effect were tested.The influence of temperature on blast furnace foundation is discussed,and the characteristics of foundation stress based on different grounds are compared.The conclusions are: 1)only the top of the foundation is affected by temperature effect;2)under vertical loading,the stress in the bottom of blast furnace foundation supported by uniform ground is low and the stress in the bottom supported by piles is high;3) there is obvious stress concentration at the interface between foudation and the upper sturcture,the way of setting the constructional reinforcement needs improvement.
2010, 40(2): 92-96.
doi: 10.13204/j.gyjz201002021
Abstract:
Based on the assumption of homogeneous isotropic soil and ignoring the dimensions of electrodes,the formula for three-dimension electric field intensity by parallel rows of electrodes was proposed.The characteristics of electric field under different spacing between opposite polarity electrodes and electrodes lengths were compared.Influence scope of electric field was also investigated.Then electric field intensity formula was simplified by considering the effect of adjacent electrode pair.Finally,the application of the theory was illustrated with the combination of case history.Parameters analysis shows that appropriate electrodes parameters can be selected in the electro-osmotic design phase by the electric field intensity formula to meet technical and economic demand.
Based on the assumption of homogeneous isotropic soil and ignoring the dimensions of electrodes,the formula for three-dimension electric field intensity by parallel rows of electrodes was proposed.The characteristics of electric field under different spacing between opposite polarity electrodes and electrodes lengths were compared.Influence scope of electric field was also investigated.Then electric field intensity formula was simplified by considering the effect of adjacent electrode pair.Finally,the application of the theory was illustrated with the combination of case history.Parameters analysis shows that appropriate electrodes parameters can be selected in the electro-osmotic design phase by the electric field intensity formula to meet technical and economic demand.
2010, 40(2): 101-104,115.
doi: 10.13204/j.gyjz201002023
Abstract:
Bond performance is the key of reinforced concrete between concrete and bars,however either corrosion or fatigue load makes bond performance deteriorate.Using a fast electric current corrosion testing of 13 bars with strain gauge placed in a machined axial cavity,the bond performance between bars and concrete under fatigue loads has been investigated,the relationship between the number of fatigue loads,corrosion amount,bond-slip of bars and concrete has been found, the degradation law of the distribution of strain in bond area of bars has also been obtained.
Bond performance is the key of reinforced concrete between concrete and bars,however either corrosion or fatigue load makes bond performance deteriorate.Using a fast electric current corrosion testing of 13 bars with strain gauge placed in a machined axial cavity,the bond performance between bars and concrete under fatigue loads has been investigated,the relationship between the number of fatigue loads,corrosion amount,bond-slip of bars and concrete has been found, the degradation law of the distribution of strain in bond area of bars has also been obtained.
2010, 40(2): 105-108.
doi: 10.13204/j.gyjz201002024
Abstract:
In order to raise the reliability of the strengthening design of a building after a fire,the exploration of the bond performance of a reinforce concrete after a fire becomes the key to the study on the behavior of the reinforced concrete after a fire.It is studies the changes in the bond performance between rebar and concrete under different temperatures by way of a central pull-out test.The rebar and the concrete cementing force's -s curves under different temperatures are obtained and the bond-slip constitutive equation under temperature influence is also given.
In order to raise the reliability of the strengthening design of a building after a fire,the exploration of the bond performance of a reinforce concrete after a fire becomes the key to the study on the behavior of the reinforced concrete after a fire.It is studies the changes in the bond performance between rebar and concrete under different temperatures by way of a central pull-out test.The rebar and the concrete cementing force's -s curves under different temperatures are obtained and the bond-slip constitutive equation under temperature influence is also given.
2010, 40(2): 109-111,119.
doi: 10.13204/j.gyjz201002025
Abstract:
Using the alternating current bridge method and the NEL method and the natural diffusion method,the check experiments for chloride diffusion of ordinary hydraulic concrete with five mix proportions are tested.Based on the tested and calculated chloride diffusion coefficients,the correlation coefficients of chloride diffusion coefficients with the water cement ratios and porosity and compressive strengths of test concrete are studied.The results show there are better correlations among those parameters,the tested diffusion coefficients using the natural diffusion method are bigger than those diffusion coefficients using the bridge method,and the tested results using the NEL method are similar to the results by the bridge method.
Using the alternating current bridge method and the NEL method and the natural diffusion method,the check experiments for chloride diffusion of ordinary hydraulic concrete with five mix proportions are tested.Based on the tested and calculated chloride diffusion coefficients,the correlation coefficients of chloride diffusion coefficients with the water cement ratios and porosity and compressive strengths of test concrete are studied.The results show there are better correlations among those parameters,the tested diffusion coefficients using the natural diffusion method are bigger than those diffusion coefficients using the bridge method,and the tested results using the NEL method are similar to the results by the bridge method.
2010, 40(2): 112-115.
doi: 10.13204/j.gyjz201002026
Abstract:
Caisson construction has many advantages,such as having a small footprint,no support of sheet pile,little impact on adjacent buildings and security of construction.The caisson technology is widely applied as the developing of the construction technology and machinery today,but some difficulties indeed exist in the construction of the large-scale irregular double-wall caisson.In this paper, some engineering instances are involved.In view of using a large-scale irregular caisson with double walls in a drainage pumping station,this article presents the problems of design and construction,the solutions and its effect during the application.This article also introduces the sinking technology,monitoring system and the method of vertical correction in detail.
Caisson construction has many advantages,such as having a small footprint,no support of sheet pile,little impact on adjacent buildings and security of construction.The caisson technology is widely applied as the developing of the construction technology and machinery today,but some difficulties indeed exist in the construction of the large-scale irregular double-wall caisson.In this paper, some engineering instances are involved.In view of using a large-scale irregular caisson with double walls in a drainage pumping station,this article presents the problems of design and construction,the solutions and its effect during the application.This article also introduces the sinking technology,monitoring system and the method of vertical correction in detail.
