Stress concentration factors in circular hollow section T-joints with concrete-filled chords

The use of welded trusses made up of concrete filled circular hollow sections (CFCHS) is currently being increased in highway bridges in many countries. Most bridge failures are due to fatigue problems in welded joints. Therefore, many research studies are paying attention to the improvement of fatigue strength in these types of joints. Cyclic loading has direct impact on increasing the chance of fatigue to occur, especially at hot spot locations, where cracks are likely to initiate and propagate. In this paper, experiments on a welded concrete filled circular hollow sections (CFCHS) T-joint with a small non-dimensional parameter, β (ratio of diameter of brace, d, to diameter of chord, D) subjected to axial loads and in-plane bending are presented to determine the strain concentration factors (SNCF) on hot spots in a welded joint