Test Analysis on Prestressed Frames with Three Kinds of Beam-column Section Strength

"Strong column with weak beam","strong beam with weak column" and"column & beam with equal strength"can be existed in one-storey prestressed concrete frames and the top storey of mult-storey prestressed concrete frames.Through the test of four prestressed concrete frames under vertical load,three kinds of prestressed concrete frames performances are studied,such as ultimate load,deflection,displacement ductility,redistribution of internal force.When the relative height of equivalent compression zone is smaller enough,the test proves that three kinds of prestressed concrete frames can realize full redistribution of internal force and have better displacement ductility,the width of cracks and deflections can satisfy the rules of code for design of concrete structures.     

基于针入度与PG分级的沥青胶结料技术指标对比研究

沥青胶结料是沥青路面的重要组成部分,评价沥青胶结料路用性能的常规方法是针入度方法,美国的战略研究计划(SHRP)开发了一个新的评价沥青胶结料性能的方法,即Superpave沥青胶结料路用性能PG方法,针入度规范的主要技术指标就是沥青的三大指标(针入度、延度、软化点),而沥青胶结PG方法主要指标是高温车辙因子、中温疲劳因子、低温蠕变劲度及最大拉应变等,基于两套规范的差别,从理论方面进行对比研究,研究主要有两个方面,一是从宏观角度对两套规范进行对比,分析其表面的异同,另一方面从每个主要指标进行着手,对比分析其理论方面的异同。     

抗震结构的概念设计

安全、合理而经济的结构设计必须注重概念设计。概念设计必须综合考虑,计算是一种手段,计算本身也必须概念正确,才有助于分析,概念清楚才有助于宏观的控制。     

钢管混凝土半刚性节点有限元建模方法的研究

该文建立了矩形钢管混凝土半刚性连接节点———双T板(DST)节点的三维非线性有限元计算模型,并考察了轴压比、材料性能、构件尺寸等因素变化对其滞回性能、强度刚度退化及延性等受力性能的影响。分析结果表明,有限元模型计算结果与试验结果吻合良好,从而验证了模型的正确性。根据分析结果,给出了节点构造的改进意见。     

方钢管混凝土柱轴压比限值的研究

在方钢管混凝土柱压弯试验的基础上,探讨了轴压比影响柱延性的原因,并推导了试验轴压比与设计轴压比的换算关系公式。最后根据换算关系公式和试验数据,以层间弹塑性位移角作为延性控制指标,提出了方钢管混凝土框架柱的轴压比限值,以供设计参考。     

Relationship between curvature ductility of column and structural displacement ductility for concrete frame structures

Based on the domestic experimental data of multi-storey concrete frame structures, the relationship between curvature ductility of concrete frame column and structural displacement ductility is proposed. 32 sets experimental data of system displacement ductility and the corresponding storey displacement ductility, which are mainly obtained from beam hinge yield mechanism and failure mechanism, are collected, and statistical property of system placement ductility is analyzed. Curvature ductility of concrete frame column is derived from storey displacement ductility factor by the classical analytic solution, and relationship between curvature ductility of frame column and structural displacement ductility is established. Correlation coefficient (R) for fitting power exponent function model and sample test data is 0.775. Results of nonlinear numerical analysis examples show that statistical function model is able to direct the ductility control design of concrete frame column.     

Failure Analysis and Ductility Optimization of CFSST Stub Column with Inner CFRP Tube Under Axial Compressive Load

In order to analyze the failure and optimize the ductility of concrete-filled square steel tubular stub column with inner CFRP tube (CFSST-CFRP) under axial compressive load, the mechanical behaviors of specimens in related tests were analyzed by a finite element software ABAQUS. And failure analysis was made. A reasonable expression on ductility optimization and improvement is drawed through nonliner regression. The results indicate that CFRP fracture is a principal reason of CFSST-CFRP stub column failure under axial compressive load. Meanwhile, its ductility can be improved by increasing the value of ξf/ξs. Concrete-filled square steel tubular (CFST) stub column crack more seriously than CFSST-CFRP, and CFSST-CFRP stub column is not functioning adequately, without available CFRP bonded.     

Numerical Simulation Analysis on Ductility Performance of High Strength RC Frame Structure

High-strength concrete has been widely used in civil structures for advantages of higher-strength, earlier curing strength and smaller deformation in applications. However, relatively weak ductility in structures in seismic zones prevented it from further application. The ductility of the structure can be improved by reinforcing reasonably rebars in correct details. A high strength RC frame model with twelve floors and two bays is numerically analyzed by using DRAIN-2DX program. It was shown that this worked fairly well in simulation of the process of structural damage and energy dissipation capacity. It also showed that this kind of frame structure has good ductility and dissipation capacity as well as great seismic performance. The proposed method can be applied in high-strength concrete structures in seismic zone.     

兴安落叶松规格材齿板连接节点的拉伸性能

采用国产落叶松规格材及进口齿板连接件构造节点,依据国标对齿板接合节点的延性比、齿极限承载力、齿板极限受拉承载力及设计值进行评估。结果表明,采用Foschi公式对试验曲线进行拟合,结果良好;齿板节点的延性比随节点构造方式的不同而异,顺纹节点的延性比均大于2.0,明显高于横纹节点,符合抗震结构的要求。