Shaking table investigations on seismic performance of prefabricated corrugated steel utility tunnels

A series of shaking table model tests were performed to investigate dynamic responses and damage mechanisms of prefabricated corrugated steel utility tunnels holding various brackets and pipelines. Details of the shaking table experimental setup for this kind of new utility tunnel are presented in this paper for the first time. Multiple seismic responses are measured, including the displacement of the soil surface, acceleration and strain of the utility tunnel, pipelines and brackets, as well as the acceleration and dynamic earth pressure of the test soil. The results demonstrate that the model box designed by our lab did not impose an obvious boundary effect. Displacement of the overlying soil above two sides of the utility tunnel was larger than that of the center of the model in the field nearby. The acceleration response of the structure was perfectly consistent with the surrounding soil. Dynamic earth pressures acting against the tunnel sidewall were significantly affected by the tunnel’s mass distribution under strong excitations. Response acceleration varied with different kinds of pipelines and brackets. The peak strain obtained from the suspending bracket was larger than that of the standing bracket. Different types of brackets were suitable for different applications. Both of the utility tunnel and brackets were not yielded under strong ground motions. The results provide valuable insight into the seismic performance of the shallow-buried underground steel structure and the safe design of the prefabricated corrugated steel utility tunnel.