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).

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.

Seismic Investigation of Steel Pile Bents: II. Retrofit and Vulnerability Analysis

2002 ◽  
Vol 18 (1) ◽  
pp. 143-160 ◽  
Author(s):  
Ayman A. Shama ◽  
John B. Mander ◽  
Stuart S. Chen
Keyword(s):  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Vulnerability Analysis ◽  
Experimental Results ◽  
Experimental Program ◽  
Seismic Investigation ◽  
Seismic Vulnerability Analysis ◽  
Plastic Steel

This paper is the second of a two-part study on the seismic vulnerability of deck bridges supported on steel pile bents. A conceptual elastic cap/elasto-plastic steel pile retrofit strategy is proposed in this part with the aim of strengthening the connection and ensuring plastification takes place only in the steel pile. An experimental program was carried out to assess the retrofit strategy. On the basis of the experimental results for existing as well as retrofitted connections, a seismic vulnerability analysis for bridges supported by steel pile bents was performed. Fragility curves for such structures were developed using a simplified fundamental mechanics-based approach. The study showed that the retrofitted connections exhibited superior energy absorptions with respect to the existing connections. Fragility curves also demonstrated the effectiveness of the retrofit strategy proposed.

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.

Seismic Behavior of Horizontally Irregular Structures: Current Wisdom and Challenges Ahead

2016 ◽  
Vol 68 (6) ◽  
Author(s):  
Suvonkar Chakroborty ◽  
Rana Roy
Keyword(s):  
Seismic Behavior ◽  
Ground Motions ◽  
Response Assessment ◽  
Design Guidelines ◽  
Research Progress ◽  
Future Research ◽  
Irregular Structures ◽  
Traditional Design ◽  
The Subject ◽  
Code Provisions

In view of the stronger vulnerability of horizontally irregular structures during earthquakes, numerous studies have been made since mid-1950 s. Unfortunately, research progress in this subject does not appear encouraging. This is evident from the current wisdom embodied in modern codes in the form of design guidelines. Beginning with a critical review of the earlier works and the available code-provisions, the present paper emphasizes on the prevalent controversies and the fundamental fallacies in research studies and traditional design. The review intends to address the strength vis-a-vis weakness of the studies accomplished so far and helps streamlining future research. The present paper also summarizes the updated views for selecting and processing appropriate set of ground motions. This is a key input in seismic response assessment and a major reason of the existing controversies in the subject of asymmetry. A prognostic scrutiny of the research progress recognizes the prospective challenges ahead.

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 Fragilities of High-Voltage Substation Disconnect Switches

2019 ◽  
Vol 35 (4) ◽  
pp. 1559-1582
Author(s):  
Bai Wen ◽  
Mohamed A. Moustafa ◽  
Dai Junwu
Keyword(s):  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Ground Motions ◽  
Incremental Dynamic Analysis ◽  
Nonlinear Finite Element ◽  
Power Grids ◽  
Finite Element Models ◽  
Severe Damage ◽  
Substation Equipment ◽  
Motion Characteristics

Electrical substations and vital components, e.g., disconnect switches, experienced severe damage that caused blackouts during past earthquakes. To improve the seismic resiliency of power grids and use probabilistic decision-making frameworks, comprehensive fragility data for the different substation equipment are needed. The objective of this study is to investigate the seismic performance of and develop component and system fragility curves for a critical substation component: disconnect switches. The seismic vulnerability of two common switch types was evaluated and two operational configurations were considered. Detailed nonlinear finite element models for the full switches were calibrated using previous experimental data and used to conduct incremental dynamic analysis and carry out the fragility assessment. A total of 160 triaxial ground motions representing four sets of different ground motion characteristics were used. The switches’ fragility curves were developed and presented to be readily used for new substation design, prioritizing retrofit/maintenance activities and reliability assessment of power grids.

scholarly journals Comparison of ground motions estimated from prediction equations and from observed damage during the <i>M</i> = 4.6 1983 Liège earthquake (Belgium)

2013 ◽  
Vol 13 (8) ◽  
pp. 1983-1997 ◽  
Author(s):  
D. García Moreno ◽  
T. Camelbeeck
Keyword(s):  
Western Europe ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Ground Motions ◽  
Gravitational Acceleration ◽  
Prediction Equations ◽  
Epicentral Area ◽  
Moderate Earthquake ◽  
Spectral Accelerations ◽  
Observed Damage

Abstract. On 8 November 1983 an earthquake of magnitude 4.6 damaged more than 16 000 buildings in the region of Liège (Belgium). The extraordinary damage produced by this earthquake, considering its moderate magnitude, is extremely well documented, giving the opportunity to compare the consequences of a recent moderate earthquake in a typical old city of Western Europe with scenarios obtained by combining strong ground motions and vulnerability modelling. The present study compares 0.3 s spectral accelerations estimated from ground motion prediction equations typically used in Western Europe with those obtained locally by applying the statistical distribution of damaged masonry buildings to two fragility curves, one derived from the HAZUS programme of FEMA (FEMA, 1999) and another developed for high-vulnerability buildings by Lang and Bachmann (2004), and to a method proposed by Faccioli et al. (1999) relating the seismic vulnerability of buildings to the damage and ground motions. The results of this comparison reveal good agreement between maxima spectral accelerations calculated from these vulnerability and fragility curves and those predicted from attenuation law equations, suggesting peak ground accelerations for the epicentral area of the 1983 earthquake of 0.13–0.20 g (g: gravitational acceleration).

Analytical Fragility Functions for Horizontally Curved Steel I-Girder Highway Bridges

2015 ◽  
Vol 31 (4) ◽  
pp. 2235-2254 ◽  
Author(s):  
Ebrahim AmiriHormozaki ◽  
Gokhan Pekcan ◽  
Ahmad Itani
Keyword(s):  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Highway Bridges ◽  
The United States ◽  
Central Angle ◽  
Curved Bridges ◽  
Horizontally Curved ◽  
Current Design ◽  
National Bridge Inventory ◽  
Horizontally Curved Bridges

Horizontally curved bridges were investigated following a statistical evaluation of typical details commonly used in the United States. Both seismically and non-seismically designed bridges are considered where the primary differences are in column confinement, type of bearings and abutment support length. Columns and bearings were found to be the most seismically vulnerable components for both categories. Central angle was identified as an important factor that increases the demand on various components, particularly columns. Furthermore, larger angles lead to increased deformations at the supports which adversely affect the seismic vulnerability. Consistent with the fragility curves that account for the central angle explicitly, a second set of system fragility curves were introduced for cases when central angle is not specified such as the case in the National Bridge Inventory. Comparison of fragility parameters to those suggested by HAZUS-MH highlighted the need for revisions to account for current design practices and central angle.

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.

Geometric Configuration Effects on Nonlinear Seismic Behavior of Concrete Gravity Dam

2018 ◽  
Vol 12 (01) ◽  
pp. 1850003 ◽  
Author(s):  
Md. Imteyaz Ansari ◽  
Mohd Saqib ◽  
Pankaj Agarwal
Keyword(s):  
Nonlinear Dynamic ◽  
Seismic Behavior ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Geometric Configuration ◽  
Gravity Dam ◽  
Concrete Gravity Dam ◽  
Gravity Dams ◽  
Concrete Gravity Dams ◽  
Dynamic Analyses

The effects of geometric configuration on the seismic vulnerability of concrete gravity dam are discussed in the present study. The seismic vulnerability of concrete gravity dams has been represented through fragility curves obtained through incremental dynamic analyses by considering their nonlinear dynamic behavior. Five different geometries of concrete gravity dams are considered and fragility analyses are carried out on the basis of Incremental Dynamic Analyses. The effect of smoothening of re-entrant corners in the geometry of high concrete gravity dam is also presented as a possible solution.

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