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Title of Thesis

Study Of Energy Dissipation Capacity Of RC Bridge Columns Under Seismic Demand

Author(s)

SYED MOHAMMAD ALI

Institute/University/Department Details
Department of Civil Engineering / N.W.F.P. University of Engineering and Technology, Peshawar
Session
2009
Subject
Civil Engineering
Number of Pages
275
Keywords (Extracted from title, table of contents and abstract of thesis)
Study, Energy, Dissipation, Capacity, RC Bridge, Columns, Seismic, Demand, concrete piers, quasi-static tests

Abstract
Field studies were carried out to investigate various parameters of bridges found in northern part of Pakistan. After the large Kashmir earthquake of Mw7.6 in 2005, detailed field investigations to study the seismic performance of bridges was also undertaken. A mathematical function to define the functionality of bridges was developed which is helpful for quantifying the seismic resilience of bridges. Criterion for minimum required functionality for different bridges and limit states were defined for extremely large rare earthquake and for moderate occasional earthquakes.
From the field data, typical parameters of reinforced concrete bridges were established. A series of experimental studies were undertaken in the laboratory on four scaled models of a typical bridge that consists of pier having single column. The pier column was of low strength concrete with solid circular cross section. The objective of the study was to experimentally determine the energy dissipation capacity of low strength concrete piers. Two types of tests were done on the four bridge piers: quasi-static cyclic tests and free vibration tests before, during and after the quasi-static tests.
From the experimental results on four scaled low strength bridge piers damping was seen to decrease with increase in damage, natural period of piers doubled near failure, energy degradation was seen to be more in low strength piers. Energy based strength degradation and pinching is predominant in low strength concrete piers along with large permanent deformations. Response modification (R) factors based on natural period of bridge are found to better represent the energy dissipation and are accordingly proposed. The values of R-factor calculated for low strength concrete piers are lower than AASHTO LRFD 2007 thus more conservative. The fragility curves plotted for the bridge columns indicate that for peak ground accelerations (PGA) of seismic Zone 3 and above of the seismic hazard map of Pakistan (for 475-years return period) pushes the bridge in to damage state that is allowed for large earthquakes only (with return period of 2,500 years)
Mathematical function for the quantification of seismic resilience of bridges is proposed for the first time. It is demonstrated that using the general guidelines of AASHTO LRFD 2007 quantification of seismic resilience is possible.

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S. No. Chapter Title of the Chapters Page Size (KB)
1 0 CONTENTS

 

vii
358 KB
2

1

INTRODUCTION

1.1 Background

1.2 Problem Statement and Research Objectives

1.3 Assumptions and Limitations

1.4 Outcome of Present Study

1.5 Dissertation Organization

1
215 KB
3 2 LITERATURE REVIEW

2.1 Introduction

2.2 Field Survey and Seismic Resilience

2.3 Seismic Testing Methods

2.4 Experimental Testing of Bridges

2.5 Numerical Modeling

8
246 KB
4 3 FIELD SURVEY AND DATA COLLECTION

3.1 Introduction

3.2 Field Survey

3.3 Earthquake of October 8, 2005

3.4 Quantifying the Functionality

3.5 Recording of Earthquake Time Histories

3.6 Summary and Conclusions

24
1,320 KB
5 4 MODELING AND EXPERIMENTAL WORK

4.1 Introduction

4.2 Study of Lab Equipment

4.3 Formulation of Testing Methodology

4.4 Similitude Analysis

4.5 Model Geometry

4.6 Model Mass

4.7 Model Materials

4.8 Summary of Parameters for Prototype and Model

4.9 Experimental Setup

4.10 Test Protocol

67
3,390 KB
6 5 EXPERIMENTAL RESULTS

5.1 Introduction

5.2 Identification of Dynamic Characteristics Before Cyclic Testing

5.3 Quasi-Static Cyclic Testing

5.4 Summary and Conclusions

128


3,115 KB
7 6 NUMERICAL STUDIES

6.1 Introduction

6.2 Selection of Software for Nonlinear Numerical Modeling

6.3 IDARC2D 7.0 Software

6.4 Numerical Model and Its Calibration

6.5 Seismic Design of Highway Bridges MCEER/ATC-49

6.6 Inelastic Nonlinear Time History Analysis

6.7 Summary and Conclusions

192


895 KB
8 7 SUMMARY & CONCLUSIONS

7.1 Summary

7.2 Conclusions

7.3 Future Studies

234


602 KB
9 8 REFERENCES

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408 KB