资源预览内容
第1页 / 共86页
第2页 / 共86页
第3页 / 共86页
第4页 / 共86页
第5页 / 共86页
第6页 / 共86页
第7页 / 共86页
第8页 / 共86页
第9页 / 共86页
第10页 / 共86页
亲,该文档总共86页,到这儿已超出免费预览范围,如果喜欢就下载吧!
资源描述
湖南大学硕士学位论文波形钢腹板组合箱梁抗剪及抗弯分析姓名:刘志才申请学位级别:硕士专业:桥梁与隧道工程指导教师:李立峰20070516波形钢腹板组合箱梁抗剪及抗弯分析 II 摘 要 体外预应力波形钢腹板组合箱梁是一种新型的钢混凝土组合结构,在日本和法国得到了广泛应用。与传统的预应力混凝土箱梁相比,该结构具有自重轻、受力明确、跨越能力大、施工周期短、造型美观等突出优点;与平钢腹板组合箱梁相比,该结构不需要设置纵向加劲肋来防止腹板屈曲,且提高了预应力的加载效率。 本文针对这种结构的弯曲受力性能,包括抗剪和抗弯两个方面进行了理论分析和试验研究。主要做了以下工作: (1)推导了波形钢腹板沿桥纵向刚度的计算公式,由此说明波形钢腹板对截面轴向刚度和抗弯刚度的贡献可以忽略。 (2) 两根梁的静载试验表明, 波形钢腹板组合箱梁的弯曲正应变分布符合 “拟平截面假定” :波形腹板正应变为零,混凝土顶底板正应变则符合线性分布规律;偏安全地可以认为波形腹板承担了截面上全部的剪力,剪应力沿梁高均匀分布。同时分别基于弹性和塑性分析,定性地说明了波形钢腹板组合箱梁在抗弯方面的优越性。 (3)采用小挠度线性理论,将局部屈曲和整体屈曲板件分别比拟成四边受剪的矩形板和正交异性板,推导了各自的临界剪应力计算公式。参照美国 Hamilton教授的 42 个波形钢腹板试件的模型试验情况和试验结果, 并对其进行了空间有限元分析,分析中考虑了材料几何双重非线性的影响,对初始缺陷的取值方法及其对屈曲荷载的影响、屈曲全过程也进行了详细研究。根据试验结果和有限元分析值,提出了局部屈曲和整体屈曲的理论计算公式。 (4)基于截面的 NM 关系编制了波形钢腹板组合箱梁的受弯承载能力全过程分析程序,并进行了一根梁的弯曲破坏试验,程序计算值与试验结果吻合良好。 (5)采用受弯承载力全过程分析程序进行了大量的参数分析,包括体外索的二次效应、有无跨中横隔板、跨高比及受拉区普通钢筋数量对结构极限承载力的影响;并将程序计算值与以往部分实桥及预应力混凝土桥梁采用的设计公式相对比, 对体外预应力波形钢腹板组合箱梁正截面抗弯承载力的计算方法提出了建议。 关键词:波形钢腹板组合箱梁;体外预应力;局部屈曲;整体屈曲;受弯全过程分析;正截面抗弯承载力 硕士学位论文 III Abstract The externally prestressed composite box girder with corrugated steel webs is a new type of composite steel-concrete structure. It has gained wide application in Japan and France. Comparing with traditional prestressed concrete, this structure holds specific mechanical behavior, lightens self-weight, increases the capacity of span, shortens construction period, and beautifies the mold. Comparing with composite box girders with flat steel webs, it doesnt need longitudinal ribs to avoid web buckling, and enhances loading efficiency of prestress. In this thesis, a series of experimental researches and theoretical analyses of the flexural behavior including shear and bending resistance relating to this new structure are conducted. The main work is described as follows: (1) This thesis deduces calculating formulas for longitudinal rigidity of the corrugated steel webs. It shows that the contribution of the corrugated steel webs to axial rigidity and flexural stiffness of the cross-section can be ignored. (2) The statically loading test of two model beams indicates that the distribution of normal strain over section depth in composite box girders with corrugated webs accords with the quasi plane assumption: first, normal strain of the corrugated webs is almost zero; next, normal strain of the top and base concrete plate tallies with linear distribution. It can be conservatively considered that the corrugated webs assume full of the shear force over the section and the shear stress is uniformly distributed. Respectively based on elastic and plastic analysis this thesis qualitatively explains its huge advantages of bending resistance. (3) The local and global shear buckling sample can be respectively assimilated to a series of flat rectangular subpanel and an orthotropic plate subjected to shear on four sides. Based on the small deflection theory, the equations for buckling stress of corrugated steel webs under shear are established. Considering both material and geometrical nonlinearities, spatial analyses of the 42 model test girders with corrugated steel webs by Professor Hamilton in America are accomplished. Unavoidable out-of-plane initial imperfections and its effects are primarily discussed. An all stage analysis of buckling performance is also researched. By comparisons between theoretical equations solution, model test results by Professor Hamilton, and spatial analysis, this thesis adjusts some safety factors and then recommends formulas 波形钢腹板组合箱梁抗剪及抗弯分析 IV for calculating local and global shear buckling stress. (4) Based on axial force- bending moment curvature relationship (NM) of sections, an all stage analysis program for flexural behavior of this structure is established. A destruction bending test for one model beam is accomplished, also. Comparisons between the program solution and model test results are shown to be satisfactory. (5) A mass of parameter analyses are carried out using the program. The influences of secondary effect for the externally prestressed cable, transverse diaphragm at span middle, area of reinforcement in tensile region and span depth ratio on the ultimate carrying capacity of the structure are detailed discussed. By comparisons between the program solution and formulas results using by some completed construction and traditional prestressed concrete, this thesis gives some advice on calculating the ultimate moment capacity in normal section. Key Words: composite box girders with corrugated steel webs; externally prestressed; local shear buckling; global shear buckling; all stage analysis of flexural behavior; ultimate moment capacity in normal section 湖湖 南南 大大 学学 学位论文原创性声明学位论文原创性声明 本人郑重声明:所呈交的论文是本人在导师的指导下独立进行研究所取得的研究成果。除了文中特别加以标注引用的内容外,本论文不包含任何其他个人或集体已经发表或撰写的成果作品。 对本文的研究做出重要贡献的个人和集体,均已在文中以明确方式标明。本人完全意识到本声明的法律后果由本人承担。 作者签名: 日期: 年 月 日 学位论文版权使用授权书学位论文版权使用授权书 本学位论文作者完全了解学校有关保留、使用学位论文的规定,同意学校保留并向国家有关部门或机构送交论文的复印件和电子版, 允许论文被查阅和借阅。
网站客服QQ:2055934822
金锄头文库版权所有
经营许可证:蜀ICP备13022795号 | 川公网安备 51140202000112号