Experimental tests on construction methods for a joint between concrete wall and steel girder involving long-time onsite welding

- Five construction methods are tested to analyze the effect of long-time onsite welding on concrete.
- Full scale gusset plate is welded to the steel plate embedded in concrete with a total of 18 passes.
- Introduction of a gap around the embedded plate is the most effective in minimizing effect of onsite welding.

To create a joint between reinforced concrete (RC) walls and steel girders in high-rise buildings, the concrete around the embedded plate cannot avoid the damage due to the heat input from a long-time welding (6-48 hours) of the embedded and gusset plates. A literature review showed insufficient research on evaluation of concrete damage due to the welding heat; furthermore, onsite construction workers did not have a clear solution to minimize the damage. In this study, five construction methods with different details are tested to analyze the effect of long-time (approximately 6 hours) onsite welding on the high-strength concrete for the joint between gusset plates and the embedded plate in a high-rise building. Five full-scale specimens with different construction details were tested and analyzed in terms of four items: 1) temperature distribution measurements, 2) compressive strength tests, 3) neutralization tests, and 4) the characteristics of cracks. In this paper, the gusset plates made of SM490 (fy = 325 MPa) were welded over the embedded plates after 28 days of curing of the concrete with a design strength of 55 MPa. Based on the experimental results, it is found that the appropriate selection of construction methods subjected to a long-time onsite welding is to form a gap around the embedded steel plate to minimize the welding heat transfer from the steel plate to concrete.