Analytical Fragility Curves for Ordinary Highway Bridges in Turkey

Abstract

This study focuses on the development of analytical fragility curves for the ordinary highway bridges constructed after the 1990s. Four major bridge classes were employed based on skew angle, number of columns per bent, and span number (only multispan bridges). Nonlinear response-history analyses (NRHA) were conducted for each bridge sample using a detailed 3-D analytical model subjected to earthquake ground motions of varying seismic intensities. A component-based approach that uses several engineering demand parameters was employed to determine the seismic response of critical bridge components. Corresponding damage limit states were defined either in terms of member capacities or excessive bearing displacements. Lognormal fragility curves were obtained by curve fitting the point estimates of the probability of exceeding each specified damage limit state for each major bridge class. Bridges with larger skew angles or single-column bents were found to be the most seismically vulnerable.

Software for Bridge-Specific Fragility Analysis

“…The effect of geometry (i.e. total deck length and width, pier height) on bridge fragility is fully recognized [1], [8], therefore different bridge geometries within the same category were studied in order to highlight the differences compared to the representative bridge [8,2]. The importance of bridge-specific fragility curves in the seismic assessment of road networks is presented in [9], highlighting the differences (lower and upper level) in fragility of bridges within the same category, compared to the representative bridge.…”

“…In most cases, bridges within a road network have different structural and geometric properties depending on the site topography, the selected structural system and construction method, and the foundation soil. In the literature [1,3,5,6,7] bridges are classified into different categories, while, under the assumption that the seismic performance of bridges within the same class is similar, fragility curves of the representative -of each category-bridge are typically used for the seismic assessment of the bridge stock. The number of spans, number of columns (single or multicolumn bents), skewness, deck type, pier type and the pier-to-deck connection, are some of the parameters considered in classification schemes available in the literature [1,3,5,6].…”

“…In this context, numerous methodologies have been developed for the seismic vulnerability assessment of bridges for different levels of seismic hazard using fragility curves; analytical [1][2][3] as well as empirical [4] procedures have been put forward. In most cases, bridges within a road network have different structural and geometric properties depending on the site topography, the selected structural system and construction method, and the foundation soil.…”

Optimum Selection of Retrofit Measures for R/C Bridges Using Fragility Curves

“…The use of fragility curves for assessing the vulnerability of bridges became a common practice during the last two decades. Numerous methodologies for the derivation of empirical [2], as well as analytical fragility curves [3,4,5,6,7,8,9] have been developed. The differences among the existing methodologies mainly lie in the quantitative definition of limit states (engineering demand parameter used, threshold values of limit states considered), the type of analysis, and the probabilistic model used for the fragility analysis.…”

Seismic Capacity and Demand Assessment in Bridge-Specific Fragility Analysis

“…The majority of the methodologies available in the literature for the derivation of fragility curves are analytical, since earthquake damage data available to derive empirical bridge fragility curves is sparse. A great number of analytical methodologies is available in the literature (Table 1), and can be classified with regard to consideration of multiple components ( [1], [2], [3], [4], [5], [6]), or only the most critical one (piers) in fragility analysis, the estimation of component or system capacity (limit state thresholds) and seismic demand (analysis method used), the uncertainty treatment and the probabilistic model used. In particular, regarding component capacity, either local ( [5], [6], [7]), or global ( [8], [9]) engineering demand parameters are used, whereas quantification of damage, namely the limit state thresholds, is commonly based on experimental results ( [10], [11], [12]).…”