Study On Structural Performance Of Coastal Bridges Under Multiple Hazards Of Earthquake And Tsunami

With the rapid development of economic globalization and infrastructure, more and more coastal bridges were built all around the world, such as Seto Great Bridge, Akashi Kaikyo Bridge, Yokohama Bay Bridge in Japan, Suramadu Bridge in Indonesia and so on. These bridges are gradually becoming important channels connecting different economic regions in the countries. Earthquake and tsunami are two natural disasters which threaten coastal bridges seriously. Tsunami triggered by earthquake may damage bridges again which have been damaged by earthquake. Multiple hazards of earthquake and tsunami will cause heavier damage to bridges.Based on Open Sees, a nonlinear finite model of the bridge is established. This paper uses nonlinear dynamic time history analysis method to assess bridge damage state under earthquake, tsunami, and multiple hazards of earthquake and tsunami. The main contents and conclusions are as follows:(1) Based on the existing studies, determine to simulate the tsunami with solitary wave through comparison.(2) Establish three-dimensional nonlinear finite analysis model, specially focus on the main components of the bridge, such as bearings, piers and beams.(3) Determine damage models of different components and use damage indexes to describe different damage states. The displacement ductility ratio of columns and the deformation of bearings are selected as damage indexes.(4) Use nonlinear dynamic time history analysis method to assess bridge damage state under earthquake, tsunami, and multiple hazards of earthquake and tsunami. In seismic analysis, the peak ground acceleration of minor, medium and major earthquake is respectively 70 gal, 200 gal and 400 gal.In tsunami analysis, the six conditions of 0.5m,1m, 2m, 3m, 4m, 5m for wave weight is considered. Under small earthquakes bridges are basically intact or only minor damage, medium damage or serious damage happens under strong earthquakes. Multiple hazards of earthquake and tsunami will increase the damage of coastal bridges. Pier curvature, bearing deformation will greatly increase, but shear force and bending moment of the end of the pier will be reduced under the impact of the tsunami when the bridges have been damaged by strong earthquake.