ABSTRACT
In old times, we were safety from earthquake, because Korea peninsula was located in Eurasian Plate.
Recently, the deaths thousands of people and property damage were occurred, caused by occurrence of earthquake in Asia (including Korea peninsula, Japan, China etc.). And, occurrence of earthquake shows a growing trend in Korea. For example, Earthquake was measured its magnitude at 4.9 near Heuksando and Baekryeongdo in 2013. If the earthquake which has similar scale would be occurred inland area, SOC will be seriously damaged. To secure SOC (Infrastructure) safety are also important economically. So it’s necessary to protect railway bridges from earthquake.
In Korea, the seismic design criteria was adapted about railway bridges since 1999. But, most general railway bridges were made by masonry or plain concrete early 1900s. Because those are vulnerable to earthquakes, we have to evaluate seismic performance. Thereafter we are going to increase seismic capacity about vulnerable bridges about earthquake.
Seismic performance evaluation was performed step by step, preliminary evaluation and detailed evaluation. Preliminary evaluation based on the literature data and field survey of the seismic performance evaluation is conducted for prioritization. And detailed evaluation based on the results of the Preliminary was carried out in order to identify.
In case of High-speed railway bridges, as the results of evaluating the seismic performance about 70 points base on the design data and field survey data, 46 points in the bearing, foundation unit and 24 points in the bearing unit is evaluated as a low seismic performance. So, there a way to improve performance is required, through appropriate reinforcement. Consider the type of fracture and damage; Bridges including damage to the composite part are to prevent immediate collapse reinforced first. Bridges having a single damaged part (bearing) put off to a later order based on priority. So, we proposed seismic retrofit according to the priority.
As the result of detailed evaluation about general railway bridges, if superstructure weight would be light, seismic safety was ensured. In case of Ramen or burial box type was safe for earthquake. The bridges which made by plain or reinforced concrete, was rated as weak 75 points in Bearing, 56 points in Pier, 120 points in construction joints, 158 points in foundation. In case of Piers, 40 of 79 in reinforced concrete and 151 of 274 in plain concrete was evaluated vulnerable for earthquake. And it was evaluated as a low seismic performance for bearing in reinforced concrete and foundation in plain concrete.
