Seismic Assessment of existing bridges in Croatia

Abstract

<p>Research on development of seismic assessment procedure for existing bridges will be presented in this paper. Both the linear response spectrum analysis and the nonlinear static pushover method are used and results were evaluated following the demands defined by current European seismic design codes. At first, this procedure is validated by its application to major Adriatic arch bridges with spans ranging from 200 m to almost 400 m as a part of an extensive project to develop their appropriate maintenance strategy. Seismic assessment is further developed and their suitability is proved at different bridge types.</p>

Seismic assessment of existing reinforced concrete arch bridges

“…the locations that must be inspected and tested. Recommendations for the collection of data on arch bridges are developed based on the analogy with EN 1998-3 [1] for buildings, guidelines provided for bridges [7], and research on Croatian arch bridges [8][9][10][11]. Required knowledge levels, adequate data collection methods such as in-situ inspections (location and extension) for arch bridges, and confidence factors CF for determining properties of existing materials to be used in the analysis, are presented in Table 1.…”

“…They provide answers about the expected bridge performance under a seismic event with acceptable accuracy, and indicate which are the most critical bridge details and elements. Based on the research conducted on Croatian arch bridges [8][9][10][11], it may be concluded that arches are not the most critical elements because they are characterized by great robustness as a result of their importance in crossing the obstacle. If bridge performance is deemed inadequate, appropriate counter-measures may be recommended based on these two assessment levels.…”

“…Section 2). According to papers [8][9][10], the linear multimodal spectral analysis, performed in both horizontal and vertical directions, covers the assessment of arches quite adequately because their response under a seismic event is generally linear as a consequence of their robustness. So, with regard to arches, an acceptable performance under a seismic design situation may be proven already at the first level.…”

“…So, with regard to arches, an acceptable performance under a seismic design situation may be proven already at the first level. Multimodal analysis of numerous existing arch bridges [8][9][10][11] shows that capturing all modes whose effective masses GRAĐEVINAR 66 (2014) 8, 691-703…”

“…Therefore, the authors suggest that a less rigid rule, requiring participation of effective mass in the amount of 80 % of a total mass, should be adopted for the accuracy of a linear multimodal spectral analysis for arch bridges. However, the second level of assessment based on the non-linear pushover analysis is needed for spandrel columns (particularly short ones near the arch crown) because their response to seismic actions is inelastic [10]. This kind of analysis has been proven appropriate for assessment of girder bridges supported with piers of variable height and short central column [3,12], which could be analogized with spandrel columns on arch bridges.…”