After the evaluation of the three parameters in the proposed creep model , which is based on the large numbers of experimental measurements of concrete creep , the influential regularities of concrete filled steel tube columns under long - term loading are investigated . by dispersing time , the method of tangent modulus is adopted to study the relation of creep strain and load time . in the end , this paper took cft specimens with representative geometry and sectional dimensions as examples and adopted the proposed method as an approach to investigate the influencing regularities of many factors , which include the ratio of long - term load to strength , the slenderness ratio , the eccentricity ratio , and the intensity grade of concrete , on cft structures 在对钢管混凝土构件长期荷载效应的分析中，本文基于三维粘弹性理论，采用三参数粘弹性模型，提出了核心混凝土徐变的三维有限元分析理论，在总结过去大量关于混凝土徐变试验实测结果的基础上拟合了模型中的三个参数，并成功将其应用于钢管混凝土徐变的三维分析计算中，得到徐变与持荷时间的关系，以典型截面形式的圆钢管混凝土轴压、偏压构件为例，对轴压比、长细比、含钢率、偏心率以及核心混凝土等级分别进行了大量的参数分析和实验对比研究，结果表明二者符合较好。
In the past , there were a large number of research studies on the behaviour of concrete - filled steel tubes ( cfst ) subjected to compression , bending or combined compression and bending , and there were a few research studies on the behaviour of cfst subjected to pure torsion , compression - torsion , bending - torsion , compression - bending - torsion and compression - bending - shearing . however , the behaviour of cfst members under complicated loading conditions still needs to be studied deeply 以往,研究者对钢管混凝土构件在轴压、纯弯和压弯荷载作用下的性能进行了大量研究,对纯扭、压扭、弯扭、压弯扭及压弯剪受力状态下的工作性能也有一些研究报道,但研究工作,尤其对压弯扭剪构件的工作机理的研究仍有必要深入进行。
Behavior and mechanism of concrete filled double - skin steel tubular ( cfdst ) beam - columns subjected to monotonic or cyclic loading were investigated . two kinds of cfdst section tubes were studied in this paper , that is , the outer steel tubes are circular hollow sections ( chs ) or square hollow sections ( shs ) , while all the inner steel tubes are chs . based on systematic parameter analysis , simplified models were derived to predict the load - carrying capacities of the composite members , and simplified moment - curvature and lateral load - lateral deflection hysteretic models , as well as ductility coefficient were suggested 本文从理论和试验两个方面较系统地研究了圆、方中空夹层钢管混凝土构件在单调加载(包括轴压、纯弯、压弯荷载)下的力学性能和工作机理,以及其在往复荷载作用下的滞回性能,并在参数分析的基础上,提出了圆、方中空夹层钢管混凝土轴压、纯弯和压弯构件承载力的实用计算方法和弯矩-曲率、荷载-位移滞回关系模型及延性系数的确定方法。
And the theoretical a nalyses done in this paper are listed below : first , the experimental data on the members of varied parameters under torsion demonstrate the general rule of the deformation while the tubular is under torsion . the paper establishes three phases of the deformation of the tubular under torsion , namely , the elastic deformation , the elastic - plastic deformation , and ultimate failure . through regression analysis , a simplified method is proposed for calculating the capabilities of the tubular under elastoplastic torsion , and the formulary for bearing value , is also recommended as a reference in engineering design 本文根据不同参数的构件受扭性能试验结果，研究了该结构受力变形全过程的基本规律，提出了受钮全过程的三个工作价段，即弹性变形阶段，弹塑性变形阶段和极限破坏阶段，经分析回归得到扭转全过程弹塑性的简化分析方法及承载力计算公式，可供工程设计参考；同时根据本文的弯扭试验结果以及对离心钢管混凝土构件进行的理论分析，推导了弯扭试验相关承载力的关系。
Based on the theoretical model , effects of influence of slenderness ratio , the changing steel ratio , strength of the steel and the concrete , load eccentricity ratio as well as pre - stress coefficient on the bearing capacity of the members considering influence of pre - stress in steel tube was discussed 分析了长细比、截面含钢率、钢材屈服强度、混凝土强度、荷载偏心率和初应力系数等因素的影响； 4提出了考虑钢管初应力影响时钢管混凝土构件承载力实用验算公式。
Based on ago study results , this paper has carried out the research on behaviour and simplified calculation methods of cfst members subjected to complicated loading conditions , the main achievements can be summarized as follows : ( 1 ) experimental tests on thirty - eight high performance concrete filled steel tubular ( hpcfst ) beam - columns were carried out . the behaviour of high performance concrete filled steel tubular beam - columns was studied , and the simplified calculation method for bearing capacity of hpcfst beam - columns was discussed 本文在以往有关研究成果的基础上,对钢管混凝土构件在复杂受力状态下的工作机理和承载力实用计算方法进行了研究,具体进行了以下几个方面的工作: ( 1 )进行了38个钢管高性能混凝土压弯构件力学性能的实验研究,考察了这类构件的力学性能,并对其承载力的计算方法进行了探讨。
It shows that the result of resistance under bending and torsion by this method is almost same as that of experiments . correlate equations of bearing capacity of this structure under complex loads are deduced . four expressions of bearing capacity of this structure under complex loads , which are press , bending and torsion , are deduced in the end 最后利用轴压、弯曲和扭转作用的两两组合作用下的极限承载力相关方程，通过适当的简化处理，就得到偏于安全的离心钢管混凝土构件在轴压、弯曲和扭转三种荷载共同作用下的承载力计算公式。
In this paper , cyclic behaviors of cfst columns after fire were investigated . the main achievements can be summarized as follows : ( 1 ) experimental studies on the behavior of cfst columns were carried out , including seventeen monotonic specimens and forty - three cyclic beam - column specimens 本文对标准火灾作用后钢管混凝土构件在往复荷载作用下的力学性能进行了研究,具体进行了如下工作: ( 1 )进行了17个钢管混凝土构件单调加载和43个钢管混凝土构件往复加载的实验研究。
For its so many merits , cft ( concrete filled steel tube ) has gotten extensive application in the engineering practice , especially in long - span bridges and high - rise buildings . researches and investigations on the bearing capacities of cft and its time - dependent behavior have been widely carried out 钢管混凝土以其诸多优点而在高层建筑和大跨度拱桥中得到广泛应用，国内外很多学者对钢管混凝土构件的极限承载力以及长期载荷作用下核心混凝土的徐变特性进行了大量的试验研究和理论探索。
Fifty concrete filled thin - walled steel tubular stub columns were axially tested , where diameter ( width ) to thickness ratio was selected as the main varied parameter . the behaviour of concrete filled thin - walled steel tubular stub column was analyzed , and the simplified calculation method of bearing capacity was discussed . based on the current test results and those reported in the literature , the upper limits of d / t and b / t of cfst members were recommended 以截面径(宽)厚比为基本参数,进行了50个薄壁钢管混凝土轴压力学性能的实验研究,考察了薄壁钢管混凝土的轴压力学性能,并对其轴压强度的计算方法进行了探讨,基于本文和其他研究者的实验结果,建议了钢管混凝土构件截面合理的径(宽)厚比限值。
