预应力混凝土框架结构剪力增大系数的研究

发布时间：2018-02-04 11:42

本文关键词： 预应力混凝土框架规范公式剪力增大系数 Pushover 分析弹塑性时程分析　出处：《华中科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：预应力混凝土结构在地震设防区域的广泛应用,以及目前研究的不充分,使得对其抗震性能的研究变得十分迫切。本文课题来源于国家自然科学基金项目(51278218),对依照我国现行《预应力混凝土结构抗震设计规程》(JGJ140-2004)设计的多层PC框架结构的梁柱剪力增大系数的取值问题进行研究。本文首先按照我国现行规程设计了四个两跨四层的PC框架结构,抗震等级分别为一级、二级、三级和四级。然后在SAP2000中建立弹塑性分析模型,对结构进行Pushover分析与弹塑性时程分析。在弹塑性模型中,主要通过P-Delta效应来考虑几何非线性,通过PMM纤维铰来考虑材料非线性。由于真实的剪切破坏难以模拟,所以本文不对结构设计剪切铰,而是通过非线性分析来得到结构构件在实际地震中所需的抗剪承载力,进而得到构件所需的剪力增大系数。由于剪切破坏是脆性的,因此采用这种方法得到的结果是可靠的。在Pushover分析中,本文针对PC框架的特点采用倒三角的侧向加载模式,取结构抗震性能点附近构件弯曲屈服时的剪力作为其抗震剪力设计值,代入现行抗震规范的抗震剪力调整公式中,反算出构件实际所需的剪力增大系数。在弹塑性时程分析中,本文分别使用SeismoMatch和SeismoArtif来选取天然波和拟合人工波。对于四个PC框架结构,均使用2组天然波与1组人工波进行分析,计算结果取3组地震动输入的包络值。最后,通过对Pushover分析和弹塑性时程分析结果的对比,本文基于文中的例子给出的先行建议为,PC框架的梁端剪力增大系数一、二、三、四级分别取1.55,1.35,1.2,1.1;柱端剪力增大系数一、二、三、四级分别取1.65,1.45,1.3,1.2。
[Abstract]:Prestressed concrete structures are widely used in seismic fortification areas, and the current research is insufficient. It is very urgent to study its seismic performance. This paper comes from the project of National Natural Science Foundation of China (51278218). According to the current Code for Seismic Design of Prestressed concrete structures in China, JGJ140-2004). In this paper, four two-span and four-story PC frame structures are designed according to the current rules of our country. The seismic grade is grade one, two, three and four respectively. Then the elastic-plastic analysis model is established in SAP2000. In the elastoplastic model, the geometric nonlinearity is mainly considered by P-Delta effect. The material nonlinearity is considered by PMM fiber hinge. Because the real shear failure is difficult to simulate, the shear hinge is not designed in this paper. By nonlinear analysis, the shear bearing capacity of the structural members in the actual earthquake is obtained, and then the shear increase coefficient is obtained, because the shear failure is brittle. Therefore, the results obtained by this method are reliable. In the Pushover analysis, this paper adopts the backward triangular lateral loading mode according to the characteristics of PC frame. The shear force of the structure near the seismic performance point is taken as the design value of seismic shear, and the formula of seismic shear adjustment of the current seismic code is added. The shear increase coefficient is calculated back in the elastic-plastic time history analysis. In this paper, SeismoMatch and SeismoArtif are used to select natural wave and artificial wave respectively. Two groups of natural waves and one group of artificial waves were used to analyze, and the envelope values of three groups of ground motion input were calculated. Finally, the comparison between the results of Pushover analysis and elastoplastic time history analysis was carried out. In this paper, based on the examples given in this paper, it is suggested that the beam end shear increase factor of PC frame should be taken as 1.55V 1.35L 1.2L 1.1s, respectively 1. 5, 2, 3 and 4. The column end shear increase coefficients of 1, 2, 3 and 4 are 1.655 / 1. 5 / 1. 3 / 1. 2 / 2 respectively.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU378.4

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