Considering the uncertainty of material performance, geometric characteristic and analysis method, the analysis of statistical parameters of the resistance of cast ball-and-socket support joints and the reliability an...Considering the uncertainty of material performance, geometric characteristic and analysis method, the analysis of statistical parameters of the resistance of cast ball-and-socket support joints and the reliability analysis are carried out by JC method （improved first-order second-moment method） based on the relevant experimental data. Results show that the resistance partial factor of the joint increases with the increase of the reliability index. The resis- tance partial factors are suggested corresponding to the reliability index under different load combinations. Moreover, the suggested resistance partial factor is adopted in reliability design, and it is found that the reliability index of the joint is larger than the target reliability index. The optimal load combination is the one in which live load plays an im- portant control role. Finally, based on the suggested resistance partial factors, the reliability analysis of cast bail-and- socket support ioints of a proiect is conducted.展开更多
This paper presents the shear performance analysis of a heavy-duty universal hinged cast steel support with the largest bearing capacity. The effect of 9 parameters ( 52 specimens) ,i. e. height of the upper support,d...This paper presents the shear performance analysis of a heavy-duty universal hinged cast steel support with the largest bearing capacity. The effect of 9 parameters ( 52 specimens) ,i. e. height of the upper support,depth of the ring of the upper support,depth of the top plate of the bottom support,height of the ribs of the bottom support,depth of the ribs of the bottom support,bolt hole diameter,number of the ribs of the bowl,depth of the ribs of the bowl,and yield strength of the material,were analyzed with a 3-dimensional elastic-plastic finite element model in which the nonlinearities of geometry,material and contact were all considered. Analysis shows that height of the upper support,depth of the ring of the upper support and yield strength of the material have a great effect on the mechanical performance of the support. Height of the upper support has the largest effect on performance price ratio of the support,and the maximum effect can be up to 160% . Depth of the top plate of the bottom support,height of the ribs of the bottom support and depth of the ribs of the bottom support have a medium effect on performance price ratio of the support,and the effect is within the limit of 15% 19% .展开更多
The present practice in Bangladesh for erection of girders is placing the girder directly on the bearing pad and joining the adjacent two spans in deck slab level by adopting expansion joints, as the bridges are prese...The present practice in Bangladesh for erection of girders is placing the girder directly on the bearing pad and joining the adjacent two spans in deck slab level by adopting expansion joints, as the bridges are presently designed as simply-supported beam bridge. The main disadvantage of this type of bridges is that, the seismic resistance is weak, and under the external force beyond the design range, the bridges are more likely to fall in danger because of failure in girders. Also they have expansion joints for each span, which affects the comfort of driving and the overall integrity of the bridge deck is poor [1]. Therefore, design and construction of the bridges have been revised to establish continuity between girders of two adjacent spans and transform the bridge as simply supported continuous beam bridge [2]. Temporary bearing (sandbox) method is proposed in this paper to solve the system transformation of continuous beam bridges. Design of the temporary bearing is very simple and can be manufactured at site. This method has been proved in construction of Arial Kha Bridge and can be applied for other similar bridges in Bangladesh.展开更多
It was reported in mid May that a2.5-meter-diameter cast supporting structure was manufactured in the Capital Aerospace Machinery Corporation,a subsidiary of CALT,breaking the 2 meters’diameter technical limit of cas...It was reported in mid May that a2.5-meter-diameter cast supporting structure was manufactured in the Capital Aerospace Machinery Corporation,a subsidiary of CALT,breaking the 2 meters’diameter technical limit of castings for launch vehicle.The supporting structure will be applied in LM-2C for launching three sat-展开更多
The compositions, technical principles and construction equipments of a new piling method used for ground improvement plastic tube cast-in-place concrete pile were introduced. The results from static load tests on sin...The compositions, technical principles and construction equipments of a new piling method used for ground improvement plastic tube cast-in-place concrete pile were introduced. The results from static load tests on single piles with different forms of pile shoes and on their composite foundations were analyzed. The distribution patterns of axial force, shaft friction and toe resistance were studied based on the measurements taken from buried strain gauges. From the point of engineering application, the pile has merits in convenient quality control, high bearing capacity and reliable quality, showing higher reasonability, advancement and suitability than other ground improvement methods. The pile can be adopted properly to take place of ordinary ground improvement method, achieving greater economical and social benefits.展开更多
基金Supported by National Natural Science Foundation of China (No.51078259)Seed Foundation of Tianjin University (No.2010XG-0013)Program for New Century Excellent Talents in University (No.1102010)
文摘Considering the uncertainty of material performance, geometric characteristic and analysis method, the analysis of statistical parameters of the resistance of cast ball-and-socket support joints and the reliability analysis are carried out by JC method （improved first-order second-moment method） based on the relevant experimental data. Results show that the resistance partial factor of the joint increases with the increase of the reliability index. The resis- tance partial factors are suggested corresponding to the reliability index under different load combinations. Moreover, the suggested resistance partial factor is adopted in reliability design, and it is found that the reliability index of the joint is larger than the target reliability index. The optimal load combination is the one in which live load plays an im- portant control role. Finally, based on the suggested resistance partial factors, the reliability analysis of cast bail-and- socket support ioints of a proiect is conducted.
基金Sponsored by the National Natural Science Foundation of China( Grant No. 50878066)the National Key Technology R&D Program during the 11th Five-Year Plan Period of China( Grant No. 2006BAJ01B02)
文摘This paper presents the shear performance analysis of a heavy-duty universal hinged cast steel support with the largest bearing capacity. The effect of 9 parameters ( 52 specimens) ,i. e. height of the upper support,depth of the ring of the upper support,depth of the top plate of the bottom support,height of the ribs of the bottom support,depth of the ribs of the bottom support,bolt hole diameter,number of the ribs of the bowl,depth of the ribs of the bowl,and yield strength of the material,were analyzed with a 3-dimensional elastic-plastic finite element model in which the nonlinearities of geometry,material and contact were all considered. Analysis shows that height of the upper support,depth of the ring of the upper support and yield strength of the material have a great effect on the mechanical performance of the support. Height of the upper support has the largest effect on performance price ratio of the support,and the maximum effect can be up to 160% . Depth of the top plate of the bottom support,height of the ribs of the bottom support and depth of the ribs of the bottom support have a medium effect on performance price ratio of the support,and the effect is within the limit of 15% 19% .
文摘The present practice in Bangladesh for erection of girders is placing the girder directly on the bearing pad and joining the adjacent two spans in deck slab level by adopting expansion joints, as the bridges are presently designed as simply-supported beam bridge. The main disadvantage of this type of bridges is that, the seismic resistance is weak, and under the external force beyond the design range, the bridges are more likely to fall in danger because of failure in girders. Also they have expansion joints for each span, which affects the comfort of driving and the overall integrity of the bridge deck is poor [1]. Therefore, design and construction of the bridges have been revised to establish continuity between girders of two adjacent spans and transform the bridge as simply supported continuous beam bridge [2]. Temporary bearing (sandbox) method is proposed in this paper to solve the system transformation of continuous beam bridges. Design of the temporary bearing is very simple and can be manufactured at site. This method has been proved in construction of Arial Kha Bridge and can be applied for other similar bridges in Bangladesh.
文摘It was reported in mid May that a2.5-meter-diameter cast supporting structure was manufactured in the Capital Aerospace Machinery Corporation,a subsidiary of CALT,breaking the 2 meters’diameter technical limit of castings for launch vehicle.The supporting structure will be applied in LM-2C for launching three sat-
基金Project (2007H03) supported by Communications Department of Zhejiang Province
文摘The compositions, technical principles and construction equipments of a new piling method used for ground improvement plastic tube cast-in-place concrete pile were introduced. The results from static load tests on single piles with different forms of pile shoes and on their composite foundations were analyzed. The distribution patterns of axial force, shaft friction and toe resistance were studied based on the measurements taken from buried strain gauges. From the point of engineering application, the pile has merits in convenient quality control, high bearing capacity and reliable quality, showing higher reasonability, advancement and suitability than other ground improvement methods. The pile can be adopted properly to take place of ordinary ground improvement method, achieving greater economical and social benefits.
