Seismic Performance Analysis Of Existing Damage Pile-pier Structure In Deep Water

Bridge structure plays an important role in lifeline engineering systems. In recent years, the bridge construction has developed rapidly in our country, all kinds of bridges across the river and ocean appears in people’s life. When suffered in an earthquake, the dynamic characteristics of these bridges in deep water will change due to the interactions between the bridges and the water. Especially, when the earthquake happened, a lot of bridges have been undergone a period of service time, structures must produce a certain damage because of circumstance affect, cyclic load and other accidental factors. The accumulation of damage decreases bridge’s property as well as the capacity to resist earthquake. So it is very important to research the seismic performance of existing damage bridges in deep water. In the text, considering the impart of hydro dynamic pressure, the author establishes the finite element model of a pile-pier structure based on the shaking table test. Through the ANSYS analysis, structure damage degree as well as dynamic response of damaged structure can be known. In the end, the article analyzes the seismic performance of intact and damaged structure. The main contents include the following three aspects:1Establish the restoring force model of damaged structure. Based on the tri-linear restoring force model, the author introduces the determination method of the restoring model parameters after corrosion of reinforcement and crack of concrete on the premise that the restoring curve shape of intact and damaged structures are roughly the same. The author analyzes the affect of concrete crack through a pier model.2Confirm the damage degree and analyze the dynamic response of damaged structure under seismic action. The author introduces the steps to establish the finite element of the pile-pier model, confirm the damage degree by the contrast of frequency, and it is proved by the acceleration response on top of the pier. In the end, the author analyzes the change of peak value of displacement and acceleration on top of the model through dynamic time history analysis, the affect of damage on the dynamic response can be known.3Pushover analysis of the damaged pile-pier structure. The basic conception of pushover method are described in the text. The determination method of capacity and demand spectrum curve and performance point, the definition of the plastic hinge and the loading mode of the horizontal force are introduced in detail. The performance points and the plastic hinge of damaged structure under earthquake of8degrees and obtained through pushover analysis of uniform load mode and triangular load mode respectively. By the contrast with the intact structure pushover analysis, the affect of damage on the seismic performance can be obtained.