Abstract
Steel structures in service condition, such as bridges, offshore-structures and steel towers, are subject to pulsating loads caused by vehicles, waves, current, wind, etc. "Welding under pulsating loads" cannot be avoided in the cases of repair, reinforcement and reconstruction works.
In this study, weld cracking test under pulsating loads was carried out and solidification crack was considered from mechanical standpoint.
The main results are as follows;
(1) In weld cracking test under pulsating loads, solidification cracks occured in no solidification crack zone evaluated by Trans-Varestraint cracking test.
(2) The accumulation of total strain, εt, at weld metal in solidification crack temperature zone was proposed as a mechanical measure for solidification crack. Solidification cracks under pulsating loads occur when εt exceeds the critical strain, εcr, for crack initiation dependent on material characteristics.
(3) As an engineering and mechanical measure, the relative root gap opening displacement. Δδ, which is easily measured before welding was adopted. The relation between εt and Δδ was considered. Moreover, the practical evaluating method for prevention of solidification crack under pulsating loads using Δδ was proposed.
(4) The practical use and useful evaluating equation for prevention of solidification crack under pulsating loads of constant value was derived. Moreover, validity of the equation was concretly shown.
