公路钢结构桥梁抗疲劳设计方法研究

发布时间：2018-04-29 21:46

  本文选题：公路钢桥 + 疲劳设计　； 参考：《长安大学》2014年硕士论文

【摘要】：钢结构桥梁虽然具有自重轻、跨径大等优点，但是由于长期承受车辆荷载循环作用，加上其自身焊接连接、截面突变、应力集中等因素容易引发疲劳裂纹，严重时会发生疲劳断裂破坏。我国现行的公路桥涵钢结构及木结构设计规范中疲劳设计部分相对落后，对公路钢结构桥梁疲劳问题的特点认知不足，已经不能满足我国公路钢桥设计的需要；而我国公路钢结构桥梁设计规范还处在修订状态，因此针对这一现状开展对公路钢桥抗疲劳设计方法的研究很有必要。具体而言，本文主要做了以下工作： 1）从抗疲劳设计计算准则和计算公式、疲劳细节分类和疲劳荷载三个主要方面对国外相对成熟的AASHTO、BS5400、Eurocode、日本规范，以及我国钢结构设计规范、铁路钢桥规范和公路桥涵钢结构及木结构设计规范进行对比研究分析。 通过对AASHTO基于无限寿命法和安全寿命法的两种抗疲劳设计准则和计算公式、BS5400三级循序渐进且自成体系的抗疲劳设计准则和计算公式、Eurocode基于绝对安全设计和损伤容限设计的三等级设计（无限寿命设计、等效损伤设计和损伤累积设计）的计算准则和计算公式、日本规范基于无限寿命法和安全寿命法的简便评定和损伤累积评定计算准则和计算公式的研究，基于我国规范中的计算准则和公式，指出其中有待更新和可以沿用的部分，并给出适用于我国公路桥梁钢结构疲劳设计计算公式。 对国内外规范疲劳细节的类别、等级强度与S-N曲线特征进行对比分析，通过对国内外疲劳细节的划分原则，以及我国铁路钢桥规范中细节分类与国外规范之间的差别进行详细研究，指出我国公路钢桥规范疲劳细节划分时应采用的原则和值得注意的问题，并指出我国需要通过增加疲劳试验或开展新的疲劳试验来确定强度等级大小的疲劳细节，为我国公路钢结构桥梁中疲劳细节分类提供参考和建议。 通过对AASHTO、BS5400、Eurocode和日本规范中疲劳荷载进行研究分析，给出了疲劳荷载的主要形式。简述了标准疲劳车模型的推导方法，并以简支梁桥为例，采用有限元程序ANSYS计算分析了不同跨径下AASHTO、Eurocode和BS5400标准疲劳车、日本T荷载，以及我国公路-Ⅰ级、公路-Ⅱ级和城-A级、城-B活载车辆对简支梁跨中截面造成的弯矩幅大小，以及不同轴数的车辆造成的应力循环次数，得到我国已有车辆模型与国外的标准疲劳车辆之间的差异程度，为我国公路钢桥制定疲劳荷载提供参考。 2）以大榭第二大桥为工程背景，依据AASHTO、Eurocode和日本规范，采用有限元程序ANSYS对该桥正交异性钢桥面板的典型疲劳细节进行疲劳强度验算。通过对计算结果进行分析，，并从抗疲劳设计准则、疲劳细节分类和疲劳荷载三个方面综合考虑，得出最适合我国公路钢桥正交异性钢桥面板抗疲劳设计的规范，为我国公路钢桥正交异性钢桥面的抗疲劳设计提供参考。
[Abstract]:Although the steel structure bridge has the advantages of light weight and long span, it is easy to cause fatigue crack due to the long-term bearing of vehicle load cycle, the welding connection, the sudden change of cross section, the stress concentration and so on. Fatigue fracture will occur when it is serious. The fatigue design of highway bridge and culvert steel structure and wood structure design code is relatively backward in our country, and the characteristics of highway steel bridge fatigue problem are not well understood, which can not meet the needs of highway steel bridge design in our country. However, the design code of highway steel bridge in China is still in the state of revision, so it is necessary to study the fatigue design method of highway steel bridge in view of this situation. Specifically, the main work of this paper is as follows: 1) from the three main aspects of fatigue design calculation criterion and formula, fatigue detail classification and fatigue load, the relative mature AASHTOU BS5400 Eurocodecode, Japanese code, and steel structure design code of our country are discussed. The code of railway steel bridge and the design code of highway bridge and culvert steel structure and wood structure are compared and analyzed. This paper introduces two kinds of anti-fatigue design criteria and calculation formula of AASHTO based on infinite life method and safe life method. BS5400 three-stage, step-by-step and self-made fatigue design criterion and calculation formula are given. Eurocode is based on absolute safety design and damage capacity. Limited design three-level design (infinite life design, The Japanese code is based on the simple assessment of infinite life method and the safe life method and the study of damage accumulation assessment criterion and formula. Based on the calculation criteria and formulas in the code of our country, this paper points out the parts that need to be renewed and can be used, and gives the calculation formulas suitable for the fatigue design of steel structures of highway bridges in China. The classification, grade strength and S-N curve characteristics of fatigue details are compared and analyzed, and the classification principles of fatigue details at home and abroad are discussed. The differences between the detail classification of railway steel bridge codes in China and the foreign codes are studied in detail. The principles and problems to be paid attention to in the division of fatigue details of the code for highway steel bridges in China are pointed out. It is pointed out that fatigue details of strength grade should be determined by increasing fatigue test or carrying out new fatigue test in our country, which provides reference and suggestion for classification of fatigue details in highway steel structure bridges in China. Based on the analysis of fatigue loads in AASHTO BS5400 Eurocode and Japanese codes, the main forms of fatigue loads are given. In this paper, the derivation method of standard fatigue vehicle model is briefly introduced. Taking simply supported beam bridge as an example, the calculation and analysis of AASHTO Eurocode and BS5400 standard fatigue vehicle, T load in Japan, and highway grade I in China under different spans are carried out by using finite element program ANSYS. The magnitude of bending moment caused by the highway-class 鈪

本文编号：1821705