The Fatigue Failure Analysis of Steel Structure and Review of Collapse Accidents

Bolt-ball grid structure is a high order statically indeterminate spatial grid structure that made up of multiple root bars and the bolt-ball nodes according to a certain grid form, It has the advantages of good appearance ,simple and applicable for large span, lighter weight, stress reasonable and it used in industrial and civil architecture widely. It is important to note that many bolt-ball grid structure engineering collapse has happened in recent years though the bolt net structure has developed more mature. It is necessary for us to analysis this kind of bolt-ball serious engineering accident carefully to find out the cause of the accident, summarize experience and lessons, promote the healthy and secure development of the bolt net structure . In this paper, exampled by a certain factory building of Shanxi bolt-ball rack collapse as the research background, we will study the area of collapse network frame through the methods of field observation, deformation measurement, fracture analysis and sampling test, and analyze the failure process of the network frame, find out the accident reason finally. Main job: (1) Find out the key clues of the accident through the field observation and measurement, including the measurement of component size, the inspection of construction quality, the analysis of fracture macroscopic and the photos, etc. and retain the component samples from the collapse area. (2) Conduct the material test of the component, including mechanical properties test and chemical composition test, find out the changes in composition and property after 13 years, then determine the bolt fracture type of the high strength bolt.