Numerical Study of Seismic Performance of Reinforced Concrete Moment-Resisting Frame with Cold-Joint

In this paper, the seismic performance of reinforced concrete moment-resisting frame with cold-joint subjected to monotonic lateral load has been studied numerically using Pushover analysis. Two modes of fracture may occur for cold-joint in a frame subjected to in-plane loading. The modes are Mode-I (stress orthogonal to the local plane of the crack surface) and Mode-II (stress parallel to the crack surface but orthogonal to the crack front). In order to model cold-joint and verify its behavior in mode I and mode II fracture mechanics, first the three-point bending beam with an initial notch in the middle of the span and then the S-shaped specimen, used in the push-off test, have been modeled and validated. Furthermore, a single-story single-span bare frame has been monotonically modeled at first and validated by laboratory results. Then cold-joint has been added to this frame and analyzed. Moreover, to investigate the effect of the number of spans, the considered frame has been analyzed with two and three spans in both monolithic (MJ) and with the cold-joint (CJ) statuses. In order to investigate the seismic performance, parameters such as ultimate lateral capacity, stiffness, and ductility have been evaluated. The results of this study show that in general, the presence of cold-joint in the frame has little effect on the ultimate lateral capacity and stiffness but has a significant impact on the ductility of the frame.