EFFECT OF SKEW ANGLE ON SEISMIC VULNERABILITY OF RC BOX-GIRDER HIGHWAY BRIDGES

2013 ◽  
Vol 13 (06) ◽  
pp. 1350013 ◽  
Author(s):  
AHMED ABDEL-MOHTI ◽  
GOKHAN PEKCAN
Keyword(s):  
Ground Motion ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Nonlinear Dynamic Analysis ◽  
Highway Bridges ◽  
Skew Angle ◽  
Box Girder ◽  
Skewed Bridges ◽  
Damage States ◽  
Skew Angles

In this study, the seismic vulnerability of post-tensioned reinforced concrete box-girder highway bridges with moderate-to-large skew angles to various levels of ground motion intensity is investigated. The fragility curves are generated by performing incremental nonlinear dynamic analysis (IDA) on the bridges of skew angles of 0, 30, and 60°s. A total of 45 ground motion pairs are considered to develop the fragility curves. The damage states are presented and quantified based on the column rotational ductility and superstructure displacements at the abutments. Furthermore, the fragility curves constructed are compared against those recommended by HAZUS. It is demonstrated that as the skew angle increases, skew bridges become more vulnerable to seismically induced damages. It is also shown that the HAZUS fragility curves may not lead to a consistent prediction of the vulnerability of skewed bridges.

Analytical Fragility Curves for Ordinary Highway Bridges in Turkey

2011 ◽  
Vol 27 (4) ◽  
pp. 971-996 ◽  
Author(s):  
Özgür Avşar ◽  
Ahmet Yakut ◽  
Alp Caner
Keyword(s):  
Nonlinear Response ◽  
Fragility Curves ◽  
Ground Motions ◽  
Limit State ◽  
Highway Bridges ◽  
Skew Angle ◽  
Limit States ◽  
Point Estimates ◽  
Single Column ◽  
Skew Angles

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.

Seismic Vulnerability of Reinforced Concrete Building Based on the Development of Fragility Curve: A Case Study

2016 ◽  
Vol 845 ◽  
pp. 252-258 ◽  
Author(s):  
Erlin Wijayanti ◽  
Stefanus Kristiawan ◽  
Edy Purwanto ◽  
Senot Sangadji
Keyword(s):  
Standard Deviation ◽  
Ground Motion ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Pushover Analysis ◽  
Fragility Curve ◽  
Capacity Curves ◽  
Capacity Spectrum ◽  
Damage States ◽  
Spectrum Curve

This study aims to determine the seismic vulnerability of 5th Building of Engineering Faculty, Sebelas Maret University by developing its fragility curves. Fragility curve is a measure of probabilistic seismic performance under various ground motion. The intensity of ground motion adopted in this study is median spectral displacement, , with lognormal standard deviation, βds as uncertainty parameter. The value of lognormal standard deviation is adopted from HAZUS. The parameters of median spectral displacements are identified from the capacity spectrum curve. The capacity curve obtained from non-linear static pushover analysis. Capacity curves can be converted into capacity spectrum to identify the location of the median spectral displacement at various damage states. The obtained fragility curves provide information on the probability of various damage states to occur when certain ground motion level strikes the building under study.

scholarly journals Seismic Vulnerability Assessment of Skewed Reinforced Concrete Bridges

2021 ◽  
Author(s):  
Amr Ghanem ◽  
Do-Soo Moon ◽  
Young Joo Lee
Keyword(s):  
Reinforced Concrete ◽  
Structural Reliability ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Transportation Systems ◽  
Earthquake Ground Motion ◽  
Skew Angle ◽  
Skewed Bridges ◽  
Reliability Method ◽  
Bridge Models

Skewed bridges are commonly used in highway interchanges where the straight (unskewed) bridges are not suitable. There have been several observations of heavy damage of bridges that have geometric irregularities, especially significant skewness. Such damage severely disrupts transportation systems, leading to substantial economic consequences. Skewed bridges are often inevitable due to the complexity and lack of orthogonality of transportation networks; hence better quantification of the effects of skewness on the bridge performance is a more viable approach than avoiding skewed bridges. This research focuses on the seismic vulnerability analysis of skewed reinforced concrete (RC) bridges. From the straight to highly skewed, various bridge models are created based on design example No. 4 prepared by the US Federal Highway Administration (FHWA). A set of earthquake ground motion records is carefully selected to impose consistent seismic demands on bridges. The fragility relationships for all bridge configurations are derived from the non-linear dynamic response history analysis. A new structural reliability method is utilized to handle the computational challenge in deriving fragility curves, which incorporates the structural analysis and reliability analysis to calculate the failure probability efficiently and accurately with the first-order reliability method (FORM). An attempt is made to parameterize the problem based on the skew angle. It is shown that the skew angle has a direct effect on the seismic vulnerability of RC bridges. The results reported will be helpful for new designs of skew RC bridges.

Building Seismic Vulnerability Study for China High Rises

2013 ◽  
Vol 353-356 ◽  
pp. 2301-2304
Author(s):  
Fan Wu ◽  
Ming Wang ◽  
Xin Yuan Yang
Keyword(s):  
Ground Motion ◽  
Structural Damage ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Response Spectrum ◽  
Earthquake Ground Motion ◽  
Published Data ◽  
Rapid Urbanization ◽  
High Rise ◽  
Story Drift

High-rise buildings, as a result of rapid urbanization in China, become one of popular structure kind. However, there have been few seismic vulnerability studies on high-rise buildings, and few fragility curves have been developed for the buildings. Based on the published data of more than 50 high rises and super high rises, the structural information such as building heights, mode periods, locations and sites, the maximum design story drift ratios, are collected and analyzed. The vulnerability analysis for high rises uses response spectrum displacement as seismic ground motion input, since the structures have comparatively long natural period. Using statistics and regression analysis, the relationship between the maximum story drift ratio and response spectrum displacement is established. Based on height groups and earthquake design codes, the fragility curves of different performance levels can be developed. These curves can provide good loss estimation of high rise structural damage under earthquake ground motion.

Seismic risk assessment of RC curved bridges through fragility curves

2019 ◽  
Author(s):  
Nina N. Serdar ◽  
Jelena R. Pejovic ◽  
Radenko Pejovic ◽  
Miloš Knežević
Keyword(s):  
Risk Assessment ◽  
Urban Areas ◽  
Seismic Risk ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Curved Bridges ◽  
Damage State ◽  
Seismic Risk Assessment ◽  
Probability Of Exceedance ◽  
Damage States

<p>It is of great importance that traffic network is still functioning in post- earthquake period, so that interventions in emergency situations are not delayed. Bridges are part of the traffic system that can be considered as critical for adequate post-earthquake response. Their seismic response often dominate the response and reliability of overall transportation system, so special attention should be given to risk assessment for these structures. In seismic vulnerability and risk assessment bridges are often classified as regular or irregular structures, dependant on their configuration. Curved bridges are considered as irregular and unexpected behaviour during seismic excitation is noticed in past earthquake events. Still there are an increasing number of these structures especially in densely populated urban areas since curved configuration is often suitable to accommodate complicated location conditions. In this paper special attention is given to seismic risk assessment of curved reinforce concrete bridges through fragility curves. Procedure for developing fragility curves is described as well as influence of radius curvature on their seismic vulnerability is investigated. Since vulnerability curves provide probability of exceedance of certain damage state, four damage states are considered: near collapse, significant damage, intermediate damage state, onset of damage and damage limitation. As much as possible these damage states are related to current European provisions. Radius of horizontal curvature is varied by changing subtended angle: 25 °, 45 ° and 90 °. Also one corresponding straight bridge is analysed. Nonlinear static procedure is used for developing of fragility curves. It was shown that probability of exceedance of certain damage states is increased as subtended angle is increased. Also it is determined that fragility of curved bridges can be related to fragility of straight counterparts what facilitates seismic evaluation of seismic vulnerability of curved bridges structures.</p>

Seismic Investigation of Steel Pile Bents: I. Evaluation of Performance

2002 ◽  
Vol 18 (1) ◽  
pp. 121-142 ◽  
Author(s):  
Ayman A. Shama ◽  
John B. Mander ◽  
Blaise A. Blabac ◽  
Stuart S. Chen
Keyword(s):  
Seismic Behavior ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Ground Motions ◽  
Highway Bridges ◽  
Companion Paper ◽  
Experimental Program ◽  
Evaluation Of Performance ◽  
The Subject ◽  
Overall Performance

The main objective of this study is to assess the seismic vulnerability of a class of highway bridges existing in certain regions of the eastern and central states, where steel H-piles extends out of the soil to support the pier cap. During severe ground motions, the overall performance of the bridge will be governed by the local performance of the pile-to-cap beam connection. The scope of work was divided into several tasks as follows: (1) a theory was developed to predict the performance of the connection under lateral loading; (2) an initial experimental program was conducted to investigate the seismic behavior of the steel bents; (3) a retrofit strategy is proposed; (4) a second experimental study was carried out to validate the proposed retrofit method; and (5) fragility curves for such structures were developed. This paper deals with the first two tasks of the study. The other three tasks are the subject of a second companion paper (Shama 2002).

Seismic Vulnerability Analysis of Mid-Story Isolation and Reduction Structures Based Stochastic Vibration

2011 ◽  
Vol 243-249 ◽  
pp. 3988-3991 ◽  
Author(s):  
Pei Ju Chang ◽  
Jian Zhu
Keyword(s):  
Ground Motion ◽  
Random Sample ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Response Spectrum ◽  
Time History ◽  
Time History Analysis ◽  
Good Effect ◽  
History Analysis ◽  
Reduction Effect

This study focus on derivation of such fragility curves using classic mid-story isolation and reduction structures (MIRS) in China metropolis. A set of stochastic earthquake waves compatible with the response spectrum of China seismic code selected to represent the variability in ground motion. Dynamic inelastic time history analysis was used to analyze the random sample of structures. The result reveal that good effect for superstructure and reduction effect for substructure of MIRS is favorable and obvious under major earthquake, Weak position of MIRS was be pointed out and fragility curves of typical MIRS of China was obtained finally.

scholarly journals SEISMIC FRAGILITY ASSESSMENT AND RETROFIT OF A GOVERNMENT HOSPITAL BUILDING IN CHITTAGONG, BANGLADESH

2018 ◽  
Vol 30 (1) ◽  
Author(s):  
Md. AbulHasan ◽  
Md. Abdur Rahman Bhuiyan
Keyword(s):  
Ground Motion ◽  
Return Period ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Response Spectrum ◽  
Seismic Fragility ◽  
Earthquake Ground Motion ◽  
Type I ◽  
Type Ii ◽  
Ground Motion Records

Chittagong Medical College Hospital (CMCH) is one of the most important government hospitals in Bangladesh. It is located in the heart of Chittagong city, the only port city of Bangladesh. Bangladesh National Building Code (BNBC) is the only official document, which has been used since 1993 as guidelines for seismic design of buildings. As per the guidelines of BNBC, the CMCH building was designed for an earthquake ground motion having a return period of 200 years. However, the revised version of BNBC has suggested that the building structures shall be designed for an earthquake ground motion having a return period of 2475 years. It is mentioned that a single seismic performance objective, the life safety, of the building is considered in both versions of BNBC. Considering the significant importance of CMCH building in providing the emergency facilities during and after the earthquake, it is indispensable to evaluate its seismic vulnerability for the two types of earthquake ground motion records having return period of 200 (Type-I) and 2475 (Type-II) years. In this regard, this paper deals with the seismic vulnerability assessment of the existing ancillary building (AB) of CMCH. The seismic vulnerability of building is usually expressed in the form of fragility curves, which display the conditional probability that the structural demand (structural response) caused by various levels of ground shaking exceeds the structural capacity defined by a damage state. The analytical method based on elastic response spectrum analyses results is used in evaluating the seismic fragility curves of the building. To the end, 3-D finite element model of the building subjected to 18 ground motion records having PGA of 0.325g to 0.785g has been used in theresponse spectrum analysis in order to evaluate its inter-story-drift ratio (IDR), an engineeringdemand parameter (EDP) for developing fragility curves. The analytical results have shown thatstructural deficiencies exist in the existing ancillary building (AB) for the Type-II earthquakeground motion record, which requires the building to be retrofitted to ensure that the existingancillary building (AB) becomes functional during and after the Type-II earthquake groundmotion record.

Seismic fragility assessment of multi-span concrete highway bridges in British Columbia considering soil–structure interaction

2021 ◽  
Vol 48 (1) ◽  
pp. 39-51 ◽  
Author(s):  
A.H.M. Muntasir Billah ◽  
M. Shahria Alam
Keyword(s):  
British Columbia ◽  
Soil Structure ◽  
Seismic Vulnerability ◽  
Structural Characteristics ◽  
Fragility Curves ◽  
Highway Bridges ◽  
System Level ◽  
Soil Structure Interaction ◽  
Seismic Fragility ◽  
Structure Interaction

Fragility curve is an effective tool for identifying the potential seismic risk and consequences during and after an earthquake. Recent seismic events have shown that bridges are highly sensitive and vulnerable during earthquakes. There has been limited research to evaluate the seismic vulnerability of the existing bridges in British Columbia (BC), which could help in the decision-making process for seismic upgrade. This study focuses on developing seismic fragility curves for typical multi-span continuous concrete girder bridges in BC. Ground motions compatible with the seismic hazard were used as input excitations for vulnerability assessment. Uncertainties in material and geometric properties were considered to represent the bridges with similar structural characteristics and construction period. The fragility of the bridge is largely attributable to the fragilities of the columns, and to a lesser extent, the abutment and bearing components. The results of this study show that, although not very significant, the soil–structure interaction has some effect on the component fragility where this effect is not very significant at the bridge system level.

Parametric study of medium span bridges retrofitted with reinforced concrete jacketing

2019 ◽  
Vol 46 (7) ◽  
pp. 567-580
Author(s):  
J.M. Jara ◽  
O. Montes ◽  
B.A. Olmos ◽  
G. Martínez
Keyword(s):  
Reinforced Concrete ◽  
Parametric Study ◽  
Seismic Behavior ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Limit State ◽  
Highway Bridges ◽  
Main Emphasis ◽  
Seismic Forces ◽  
Bridge Models

Most reinforced concrete (RC) bridges in many countries are medium-span length structures built in the last decades and designed for very low seismic forces. The evolution of seismic codes and the average age of the bridges require the evaluation of their seismic vulnerability. This study assesses the expected capacity, demand and damage of seismically deficient medium-length highway bridges, supported in frame-type piers using dynamic nonlinear methodologies. A parametric study of reinforced concrete retrofitted bridges with RC jacketing was conducted. The non-retrofitted structures are 30 m span simple supported bridges with pier heights in the range of 5–25 m. The main emphasis of the study is the assessment of the jacket parameters’ contribution to the seismic vulnerability of bridges. Particularly, it is quantified how jacket thickness and reinforcement ratio affect the probability of reaching a particular damage limit state. The retrofitted scheme includes three jacket thicknesses and three different longitudinal steel ratios. The results evaluate bridge demands and fragility curves to quantify the influence of RC jacketing on the seismic response of structures and allow to select the best jacket parameters that improve the expected seismic behavior of the bridge models. Additionally, the influence of model hysteresis degradation on the expected damage of retrofitted bridges was also determined.

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