Seismic fragility assessment of integral precast multi-span bridges in areas of moderate seismicity

Abstract

In lack of seismic provisions in the pre-Eurocode ages, most of the existing Hungarian bridges were not designed for seismic actions, therefore their seismic performance is questionable. The most commonly used structural type in highway construction is the integral precast multi-girder bridge. These bridges are typically constructed as continuous multi-support systems with monolithic joints at each support, thus their behavior may be significantly different from those applying simply supported beams and conventional bearings. A parametric fragility analysis of a wide range of different layouts is carried out using detailed and advanced non-linear numerical models. The results indicate that the abutment joints are highly vulnerable and piers are also critical for longer bridges. The study implies that without seismic design, integral precast multi-girder bridges are highly susceptible to pier shear failure, the probability of collapse is relatively high. The results also provide a solid basis for retrofit planning as well as for development of design concepts of newly built structures in moderate seismic zones.

Seismic fragility assessment of existing Italian overpass bridges

“…The behavior of shear reinforcement bars is modeled by employing the force-displacement envelope proposed in FIB43 [50] based on studies performed by Psycharis and Mouzakis [51] and Dulácska [52] for pinned connections realized with Doublesided inclined dowel pin in a skew angle, while hysteretic parameters are those suggested by Simon & Vigh [53]. In the longitudinal direction the actual inclination of the crossing bars has been considered, while in the transverse direction, the formulation for non-skewed bars has been adopted.…”

Assessing seismic vulnerability of existing bridges using fragility curves

“…U svijetu je već duže vrijeme aktualna tema ocjene seizmičke oštetljivosti postojećih građevina, pa tako i mostova. Ocjenjivanje oštetljivosti provodi se za specifične regije (države), uzimajući u obzir specifičnosti mostova i potresno opterećenje mjerodavno za pojedino područje [1][2][3][4][5]. Mostovi su iznimno važan dio prometne infrastrukture, a naročito nakon izvanrednih događaja kao što je potres, kada je nužno osigurati komunikaciju s ugroženim područjima.…”

Seismic fragility of bridges: An approach coupling multiple-stripe analysis and Gaussian mixture for multicomponent structures

“…It is often assumed, for simplicity and tractability, that (1) demand follows a normal distribution in the logarithmic space (lognormality), (2) the variability of the demand is constant and independent of the IM level (homoscedasticity), and (3) component responses are linearly correlated (linear dependence). The impacts of homoscedasticity on fragility are acknowledged, and alternatives to avoid it are the use of a data collection strategy that allows one to calculate the variation of dispersion (for instance, MSA or IDA) (Bakalis and Vamvatsikos, 2018;Simon and Vigh, 2016) or the adoption of piecewise linear regression when cloud analysis is chosen (Freddi et al, 2017;Mackie and Stojadinovic, 2003). Lognormality of seismic structural demand has been validated in some studies-usually using either single-degree-of-freedom or two-dimensional frame models (e.g.…”