Failure state of steel roof structure of the show-sports hall during assembly

At the final stage of assembly of a steel truss grid over central part the show-sports hall, the heterogeneous cracks have been observed at about 65% of welds. Arisen failure hazard of the grid structure appeared already under the dead load, and after this the assembly works were stopped. An extensive analysis of different factors like: construction, execution, transport and assemble, supported by metallographic and ultrasonic tests, allowed to recognize the basic causes of the failure hazard. It was found that defective construction of the truss nodes, improper division of the structure into shop- prefabricated members and the negative effect of the both transport and assemble leaded to serious damage of the roof structure and showed the necessity of its strengthening.