谈谈钢桥的疲劳和断裂

On Fatigue and Fracture of Steel Bridges

介绍作者多年来在钢桥疲劳和断裂方面的工作成果,以及对我国钢桥疲劳和断裂问题的看法和建议,主要涉及以下方面:在1980年之前,我们是以σmax表达钢构造的疲劳强度(抗力);从回归线可以看到不同因素对疲劳致伤次数N的影响是否显著;美国NCHRP第102号及147号报告的完成条件,其所讲疲劳试验及分析结果;在疲劳开裂点,其因车辆荷载所产生的应力谱,以及疲劳验算基本原理;AASHTO 1994年版荷载与抗力系数法桥梁设计规范和我国TB10002.2-2005规范;在设计规范之中,可以将疲劳和断裂归并为同一类极限状态,并将脆断当做断裂的一种;为防止疲劳和断裂,必须慎微;请以"先进、实用、简明"为原则,先为时速≤140 km/h的标准轨距铁路拟订一钢桥设计规范。

This paper presents the author＇s work achievements in the field of fatigue and fracture of steel bridges over the years and his views and proposals in regard to the fatigue and fracture.problems of steel bridges in China. The presentations in the paper mainly covers the aspects as follows： Before 1980, the area, was used to express the fatigue strength （resistance） of steel structures in the country; from the regression curves, it can be seen that if the influence of different factors on the times N of fatigue-induced damage is significant; the completion conditions of American NCHRP 102 and 147 and the fatigue tests and their analysis results provided therein; at the fatigue cracking point, the stress spectrum due to vehicle load and the fundamental principle of fatigue checking; the Load and Resistance Factor Design, AASHTO, 1994 and the Chinese TB10002.2-2005; in the design specifications, the fatigue and fracture may be merged into the same category of ultimate state and the brittle may be treated as a one of the fracture; to prevent the fatigue and fracture, one must be cautious, please firstly formulate a code for design of steel bridges on the standard gauge railway with train running speed ≤140 km/h on the principle of “being advanced, practical and simple”.