engleski

Retrofitting of Short-to-Medium-Span Bridges in Seismic Zones: Experiences & Recommendations

In most national codes and provisions duration of bridges is at least 50 years. Some bridges which were built before 1970s either in Europe or Japan or the US have been designed with little or with no any consideration for seismic demand. Majority of these bridges were supported by reinforced concrete bents and pier walls that lack the ductility and strength to resist earthquakes. Meanwhile strong motion earthquakes have revealed all vulnerable places on each of those bridges if built in seismically active regions. After the 1971 San Fernando earthquake the US started several seismic retrofit programs. Retrofit programs in the 1980s included the first use of isolators on bridges and a program to retrofit single-column bents. These programs were greatly accelerated after the 1989 Santa Cruz (Loma Prieta) and 1994 Northridge earthquakes. After the 1994 Northridge earthquake it was observed that no serious damage would have occurred if the previous retrofit program had already been implemented. Japan also started similar programs, especially after the 1995 Kobe earthquake. Europe and Asia may not be out of this global problem and must have own retrofit programs not only for buildings (partly given in Eurocode 8, Part 3: Assessment and retrofitting of buildings, EN 1998-3:2005) but for bridges as well. Some solutions for retrofitting the abutment, bent and column of concrete bridges recommended in these programs as well as some recommendations and comments made by authors will be presented in this paper.

Retrofit programs; Earthquake loading; Ductility; Strengthening; Concrete bridge; Abutment; Bent

nije evidentirano