Ádám Zsarnóczay

Seismic Performance of Conventional Girder Bridges in Moderate Seismic Regions

AbstractThe majority of continuous girder bridges in regions of moderate seismicity were designed before the introduction of modern seismic codes that prescribe seismic design verification for such structures. The objective of this study is to investigate the seismic performance of typical Hungarian continuous girder bridges through a parametric study. A design space is described by a set of eight parameters. More than 10,000 bridge archetypes are designed without any seismic verification to mimic the design of conventional bridges. The seismic performance of each archetype is then evaluated with modal response spectrum analysis of a detailed finite-element model. The results highlight the vulnerability of piers and bearings and imply that the superstructures are not expected to fail under moderate ground motion intensities. Long bridges with short piers and large spans show the worst performance, especially if the number of fixed bearings in the longitudinal direction is small. This indicates the large i...

On the European Norms of Design of Buckling Restrained Braced Frames

The application of buckling restrained braced frames is hindered in Europe by the absence of a standardized design procedure in Eurocode 8, the European seismic design standard. The presented research aims to develop a robust design procedure for buckling restrained braced frames. A design procedure is proposed by the authors. Its performance has been evaluated for buckling restrained braced frames with chevron type brace configurations using a state-of-the-art methodology based on the recommendations in the FEMA P695 document. A special numerical material model was developed within the scope of this research to represent the behavior of buckling restrained braces more appropriately in a numerical environment. A total of 24 archetype designs were prepared and their nonlinear dynamic response was calculated using real ground motion records in incremental dynamic analyses. Evaluation of archetype collapse probabilities confirm that the proposed design procedure can utilize the advantageous behavior of buckling restrained braces. Resulting reliability indices suggest a need for additional regulations in the Eurocodes that introduce reasonable structural reliability index limits for seismic design.