On Fatigue and Fracture of Steel Bridges

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 σmax 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".