ABSTRACT
Weld fracture of a CHS-CHS joint would occur even though the predicted capacity of the weld by design codes was not reached. However, such a failure mode was often accompanied by other failure modes, thus it is not easy to identify the failure mode. By theoretical analysis, on the other hand, it is found that the local chord wall stiffness adjacent to the brace-to-chord weld is quite different along its interface, thus the stress induced in the weld is non-uniform when the brace is subjected to tension or compression. Such a Non-Uniform Stress Distribution (NUSD) may induce the premature fracture at a local critical spot. X-type CHS-CHS joint specimens, focused on weld fracture failure mode, are designed and tested. The test results are reported and the failure mechanism is investigated. The test results imply that the assumption of uniform stress distribution on the weld of CHS-CHS joints may be unsafe.
