Structural responses of cable-stayed bridges exposed to strong earthquakes during construction

Abstract This paper presents the earthquake response of the Kömürhan cable-stayed bridge with a single pylon and steel deck which was exposed to the Elazığ-Sivrice earthquake (Mw = 6.8) on January 24, 2020, while it was under construction. The distance from the epicenter to the bridge is approximately 40 km. 82% of the Kömürhan bridge was completed during the Elazığ-Sivrice earthquake in 2020. The spectral accelerations of Elazığ-Sivrice earthquake are approximately 2.5 times greater than those of the design earthquake (72-year) considered in the construction stage. In this paper, the characteristics of Kömürhan cable-stayed bridge and Elazığ-Sivrice earthquake (Mw = 6.8) are first presented. Then, a 3D numerical finite model of the Kömürhan cable-stayed bridge under construction is created. Modal and seismic responses of the deck, pylon and cables of the bridge under construction are compared for the load combinations including the design (72-year) and the Elazığ-Sivrice earthquakes. The result shows that under the 2020 Elazığ-Sivrice earthquakes, the maximum vertical displacements, axial forces, bending moments of the deck and the cable forces were three time more than the design value using the 72-year design hazard. Nevertheless, despite the significant increase in the structural response, no visual damage was observed on the structural element. This shows the robust design of the Kömürhan cable-stayed bridge.