scholarly journals Seismic Assessment Of Multi-Span Steel Railway Bridge In Turkey Base On The Nonlinear Time History Analyses

2017 ◽  
Author(s):  
Mehmet F. Yilmaz ◽  
Barlas Ö. Çağlayan
Keyword(s):  
Fragility Curves ◽  
Time History ◽  
Field Measurements ◽  
Response Analysis ◽  
Northridge Earthquake ◽  
Railway Bridge ◽  
Railway Line ◽  
Damage Data ◽  
Steel Railway Bridge ◽  
Nonlinear Time History

Abstract. It has been seen that bridges are vulnerable to earthquakes by the research studies after important earthquakes like the San Fernando earthquake (1971 USA), the Northridge earthquake (1994 USA), Great Hanshin earthquake (1995 Japan), and Chi-Chi earthquake (1999 Taiwan). These studies show that to do the seismic risk assessments for bridges, fragility curves are useful tools. There are the most used two ways to generate the fragility curves; empirically or analytically. If the damage reports from past earthquakes are available then empirical fragility curves may be developed but otherwise seismic response analysis of structures may be used to develop analytical fragility curves. In Turkey, earthquake damage data are very limited so to develop the fragility curves for the Alasehir bridge, the analytical method is used in this study. The bridge that is studied on is lying on the Manisa-Afyon railway line that is very important for both transportation and freightage. As the most of the country land covers the seismically active zones it is a necessity to find out the vulnerability of the Alasehir bridge. The Alasehir bridge is consists of six 30 m length truss system span with a total span length of 189.43 m supported by 2 abutments and 5 truss piers with height of 12.5 m, 19 m, 26 m, 33 m and 40 m. Sap2000 is used for computer model of the Alaşehir bridge and the model is refined by using field measurements. Then selected 60 different real earthquake data are used for the analysis by using the refined model. Both material nonlinearity and Δ-δ are considered during the analysis. With this study, seismic behavior of Alasehir steel railway bridge is determined. Truss piers reaction and displacements are used to determine the seismic performance of the Alasehir bridge. Different IMs are compared in terms of efficiency, practicality, and sufficiency. Component and system fragility curve are derived for most proper IMs.

scholarly journals Seismic assessment of a multi-span steel railway bridge in Turkey based on nonlinear time history

2018 ◽  
Vol 18 (1) ◽  
pp. 231-240 ◽  
Author(s):  
Mehmet F. Yılmaz ◽  
Barlas Ö. Çağlayan
Keyword(s):  
Fragility Curves ◽  
Time History ◽  
Field Measurements ◽  
Response Analysis ◽  
Railway Bridge ◽  
Intensity Measures ◽  
Railway Line ◽  
Damage Data ◽  
Steel Railway Bridge ◽  
Nonlinear Time History

Abstract. Many research studies have shown that bridges are vulnerable to earthquakes, graphically confirmed by incidents such as the San Fernando (1971 USA), Northridge (1994 USA), Great Hanshin (1995 Japan), and Chi-Chi (1999 Taiwan) earthquakes, amongst many others. The studies show that fragility curves are useful tools for bridge seismic risk assessments, which can be generated empirically or analytically. Empirical fragility curves can be generated where damage reports from past earthquakes are available, but otherwise, analytical fragility curves can be generated from structural seismic response analysis. Earthquake damage data in Turkey are very limited, hence this study employed an analytical method to generate fragility curves for the Alasehir bridge. The Alasehir bridge is part of the Manisa–Uşak–Dumlupınar–Afyon railway line, which is very important for human and freight transportation, and since most of the country is seismically active, it is essential to assess the bridge's vulnerability. The bridge consists of six 30 m truss spans with a total span 189 m supported by 2 abutments and 5 truss piers, 12.5, 19, 26, 33, and 40 m. Sap2000 software was used to model the Alasehir bridge, which was refined using field measurements, and the effect of 60 selected real earthquake data analyzed using the refined model, considering material and geometry nonlinearity. Thus, the seismic behavior of Alasehir railway bridge was determined and truss pier reaction and displacements were used to determine its seismic performance. Different intensity measures were compared for efficiency, practicality, and sufficiency and their component and system fragility curves derived.

scholarly journals Effect of Ground Motion Directionality on Fragility Characteristics of a Highway Bridge

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Swagata Banerjee Basu ◽  
Masanobu Shinozuka
Keyword(s):  
Ground Motion ◽  
Dimensional Space ◽  
Fragility Curves ◽  
Time History ◽  
Transportation Systems ◽  
Nonlinear Time History Analysis ◽  
Response Analysis ◽  
Seismic Fault ◽  
Principal Axes ◽  
Nonlinear Time History

It is difficult to incorporate multidimensional effect of the ground motion in the design and response analysis of structures. The motion trajectory in the corresponding multi-dimensional space results in time variant principal axes of the motion and defies any meaningful definition of directionality of the motion. However, it is desirable to consider the directionality of the ground motion in assessing the seismic damageability of bridges which are one of the most vulnerable components of highway transportation systems. This paper presents a practice-oriented procedure in which the structure can be designed to ensure the safety under single or a pair of independent orthogonal ground motions traveling horizontally with an arbitrary direction to structural axis. This procedure uses nonlinear time history analysis and accounts for the effect of directionality in the form of fragility curves. The word directionality used here is different from “directivity” used in seismology to mean a specific characteristic of seismic fault movement.

In-Situ Field Measurements and Numerical Model Identification of a Multi-Span Steel Railway Bridge

2014 ◽  
Vol 43 (6) ◽  
pp. 20140049 ◽  
Author(s):  
Ozden Caglayan ◽  
Kadir Ozakgul ◽  
Ovunc Tezer ◽  
Filiz Piroglu
Keyword(s):  
Numerical Model ◽  
Model Identification ◽  
Field Measurements ◽  
Railway Bridge ◽  
Steel Railway Bridge

Seismic fragility of steel moment-resisting frames in Vancouver and Montreal designed in the 1960s, 1980s, and 2010

2015 ◽  
Vol 42 (11) ◽  
pp. 919-929 ◽  
Author(s):  
Lucía Valentina Díaz Gómez ◽  
Oh-Sung Kwon ◽  
Mohammad Reza Dabirvaziri
Keyword(s):  
Numerical Models ◽  
Fragility Curves ◽  
Time History ◽  
Steel Moment Resisting Frames ◽  
Moment Resisting Frames ◽  
Nonlinear Time History Analyses ◽  
Moment Resisting ◽  
The 1960S ◽  
Steel Mrfs ◽  
Nonlinear Time History

Typical steel moment-resisting frames (MRF) of six-storey buildings in Vancouver and Montreal were designed for three different provisions of the National Building Code of Canada (1960s, 1980s, and 2010). Numerical models were developed in OpenSees to understand the seismic performance of the structures. These models accounted for strength and stiffness degradation through appropriate representations of the beam–column connection behaviours, which were calibrated against experimental results available in the literature. The behaviour of the buildings was evaluated through pushover and nonlinear time history analyses. The pushover analysis results showed that the 1960s and 2010 steel MRFs of both cities exhibited strong-column-weak-beam failure mode. The 1980s steel MRFs of both cities showed soft-storey mechanism. Fragility curves were developed for the steel MRFs based on the seismic demands evaluated using nonlinear time history analyses, which can be used for regional seismic impact assessment studies in the future.

Adaptive Spectra-Based Pushover Procedure for Seismic Evaluation of Structures

2000 ◽  
Vol 16 (2) ◽  
pp. 367-391 ◽  
Author(s):  
Balram Gupta ◽  
Sashi K. Kunnath
Keyword(s):  
Response Spectrum ◽  
Pushover Analysis ◽  
Nonlinear Dynamic Analysis ◽  
Time History ◽  
Northridge Earthquake ◽  
Seismic Evaluation ◽  
Seismic Demands ◽  
Ground Shaking ◽  
Motion Characteristics ◽  
Nonlinear Time History

The estimation of inelastic seismic demands using nonlinear static procedures, or pushover analyses, are inevitably going to be favored by practicing engineers over nonlinear time-history methods. While there has been some concern over the reliability of static procedures to predict inelastic seismic demands, improved procedures overcoming these drawbacks are still forthcoming. In this paper, the potential limitations of static procedures, such as those recommended in FEMA 273, are highlighted through an evaluation of the response of instrumented buildings that experienced strong ground shaking in the 1994 Northridge earthquake. A new enhanced adaptive “modal” site-specific spectra-based pushover analysis is proposed, which accounts for the effect of higher modes and overcomes the shortcomings of the FEMA procedure. Features of the proposed procedure include its similarity to traditional response spectrum-based analysis and the explicit consideration of ground motion characteristics during the analysis. It is demonstrated that the proposed procedure is able to reasonably capture important response attributes, such as interstory drift and failure mechanisms, even for structures with discontinuities in strength and/or stiffness that only a detailed nonlinear dynamic analysis could predict.

Probabilistic Performance Assessment of Retrofitted Horizontally Curved Multi-Frame RC Box-Girder Bridges

2017 ◽  
Vol 11 (04) ◽  
pp. 1750010 ◽  
Author(s):  
Hossein Pahlavan ◽  
Behzad Zakeri ◽  
Gholamreza Ghodrati Amiri
Keyword(s):  
Bridge Deck ◽  
Fragility Curves ◽  
Time History ◽  
Damage State ◽  
Box Girder Bridges ◽  
Box Girder ◽  
Horizontally Curved ◽  
Girder Bridges ◽  
Damage States ◽  
Nonlinear Time History

Bridge horizontal deck curvature and the prevalence of in-span hinges in multi-frame RC box-girder bridges have reinforced this class of bridge to response with unique dynamic behavior during seismic excitations. This paper assesses the impacts of 10 different retrofit strategies on the vulnerability of curved multi-frame RC box-girder bridges with multi-column bents based on nonlinear time history analyses in OpenSEES. Consistent with HAZUS-MH definitions, fragility curves corresponding to four damage states at the component and system levels are developed for various bridge deck radii. The results indicate that combinations of retrofit strategies should be used to enhance the desirable level of bridge performance. Moreover, the most effective retrofit strategy in reducing probable damage for a given intensity is dependent on the bridge deck radius and is a function of the damage state of interest.

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