Seismic Devices For Bridges
Free (open access)
D. Mestrovic & G. Grebenar
The paper summarizes earthquake calculation in accordance with Eurocode 8, ACI regulations and codes applied in Croatia (Europe). Basic data about earthquakes are given and an overview of seismic devices is presented. Calculations for Zeceve Drage (Croatia) bridge are made. Time history analysis was calculated for accelograms based on earthquakes occurring in Petrovac (1979), with magnitude of 6.8, and in Ulcinj (1979), with magnitude 5.3, (former Yugoslavia). New methods of structure protection with dampers were applied on the bridge. Spectrum analysis based on EC8/2 for ground acceleration of 0.19g for the past period of 500 years, and time history analysis for ground acceleration of 0.25g and for the past period of 1000 years was used. The damper effect on a bridge with two spans was tested in a laboratory of Civil Engineering Faculty of Zagreb University, Croatia. Keywords: seismic devices, damper, elastomer bearing. 1 Introduction When designing structures in seismically active regions, it is essential to know characteristics of ground motion. Regulations usually determine maximum effective ground acceleration. The earthquake ground shaking is usually presented in the form of a response spectrum of acceleration. That acceleration is actually an attempt to describe potentially destructive ground motion. Generally, acceleration tends to be equal with actual maximum ground acceleration resulting from an earthquake. Site conditions of soil, such as its type and load bearing capacity, are also important. If short periods prevail, structure is rigid and founded on rocky soil, then such structure has small natural periods and earthquake would have catastrophic effects on this kind of structure. And if a structure is slender and founded on soft ground and subjected to earthquake with predominant longer
seismic devices, damper, elastomer bearing.