Seismic Risk Assessment of Masonry Arch Bridges in the United States

67 Pages·2017·2.16 MB·English

Clemson University
TigerPrints
All Theses Theses
12-2017
Seismic Risk Assessment of Masonry Arch Bridges
in the United States
Aditya Prakash Kamath
Clemson University
Follow this and additional works at:https://tigerprints.clemson.edu/all_theses
Recommended Citation
Kamath, Aditya Prakash, "Seismic Risk Assessment of Masonry Arch Bridges in the United States" (2017).All Theses. 2790.
https://tigerprints.clemson.edu/all_theses/2790
This Thesis is brought to you for free and open access by the Theses at TigerPrints. It has been accepted for inclusion in All Theses by an authorized
administrator of TigerPrints. For more information, please [email protected].
SEISMIC RISK ASSESSMENT OF MASONRY ARCH BRIDGES IN THE
UNITED STATES

A Thesis
Presented to
the Graduate School of
Clemson University

In Partial Fulfillment
of the Requirements for the Degree
Master of Science
Civil Engineering

by
Aditya Prakash Kamath
December 2017

Accepted by:
Dr. Sez Atamturktur, Committee Chair
Dr. Nadarajah Ravichandran
Dr. Mohammad Javanbarg
Dr. Saurabh Prabhu
i
ABSTRACT

Over 1600 masonry arch bridges serve as part of the U.S. transportation infrastructure
system. The preservation of these bridges is important due not only to their role in transportation
network, but also to their cultural, architectural, and historic value to the nation. For successful
preservation, the stewards of these historic bridges must be equipped with tools to make risk-
aware decisions, considering both the susceptibility of the region to an extreme seismic event and
the vulnerability of the bridge to undergo structural damage. To aid the stewards of these bridges,
this master’s thesis develops Infrastructure Risk Indices (i.e. the probability of failure for local
seismic hazard) for the masonry arch bridge inventory of the nation through non-linear finite
element modeling coupled with fragility analysis under site-appropriate seismic excitation. The
risk indices presented herein can aid the development of retrofitting strategies to help minimize
risk and in turn, minimize financial loss, as well as loss of cultural heritage of the structures.

ii
DEDICATION

I would like to dedicate this thesis to my parents Prakash Kamath and Mamta Kamath.
iii
ACKNOWLEDGMENTS

I would like to thank my adviser, Dr. Sez Atamturktur and my committee members Dr.
Nadarajah Ravichandran, and Dr. Mohammad Javanbarg for their constant support and
encouragement throughout my degree program. I want to thank Dr. Bryant Nielson from
whose meticulous work has contributed to this thesis. I would like to thank Dr. Saurabh
Prabhu from American Insurance Group, for his constant support throughout my
program. Finally, I would like to thank the PTT Grants program of National Center for
Preservation Technology and Training (NCPTT) of Department of Interior, for providing
the funds that made this work possible.

iv
TABLE OF CONTENTS
Page
TITLE PAGE ................................................................................................................................. i
ABSTRACT .................................................................................................................................. ii
DEDICATION ............................................................................................................................. iii
ACKNOWLEDGMENTS .......................................................................................................... iv
LIST OF FIGURES .................................................................................................................... vii

LIST OF TABLES ............................................................................................................. ix
CHAPTER ONE : INTRODUCTION ................................................................................ 1
1.1 Motivation and Background ...................................................................................................... 1
1.2 Background Perspectives on Fragility Analysis ........................................................................ 3
i) Empirical Fragility Curves .............................................................................. 4
ii) Expert Based Fragility Curves ......................................................................... 5
iii) Analytical Fragility Curves ............................................................................. 5
1.3 Overview of the Research Campaign ........................................................................................ 8
CHAPTER TWO : ANALYSIS OF THE NATIONAL BRIDGE INVENTORY (NBI)
AND ARCHETYPE DEVELOPMENT ..................................................................... 10
2.1 Single-Span Masonry Arch Bridge Inventory ......................................................................... 10
2.2 Clustering to Obtain Representative Bridge Archetypes ......................................................... 11
CHAPTER THREE : NUMERICAL MODEL DEVELOPMENT .................................. 15
3.1 Development of Geometric Representation ............................................................................ 15
3.2 Selection of Element Type and Material Model ...................................................................... 17
3.3 Definition of Support Conditions ............................................................................................ 18
3.4 Determination of Material Model Properties for the Masonry Assembly ............................... 19
v
Table of Contents (Continued)
Page
3.5 Mesh Refinement .................................................................................................................... 20
CHAPTER FOUR : SEISMIC HAZARD, SELECTION OF GROUND MOTION
RECORDS AND COLLAPSE MECHANISM .......................................................... 22
4.1 Selection of Ground Motions .................................................................................................. 24
4.2 Selection of Collapse Mechanism ........................................................................................... 27
CHAPTER FIVE : PROBABILISTIC SEISMIC DEMAND MODELS AND
FRAGILITY CURVES ............................................................................................... 29
5.1 Probabilistic Seismic Demand Model ..................................................................................... 29
5.2 Fragility Curves ....................................................................................................................... 34
5.3 Risk Index ................................................................................................................................ 40
CHAPTER SIX : CONCLUSION .................................................................................... 43
REFERENCES ................................................................................................................. 46

vi
LIST OF FIGURES

Figure Page
Figure 1 : A representative fragility curve for a specified limit state. ............................................. 3
Figure 2 : Probabilistic capacity and demand curves. ..................................................................... 7
Figure 3 : Methodology adopted to generate fragility curves.......................................................... 9
Figure 4 : Components of a single-span masonry arch bridge. ..................................................... 10
Figure 5 : Distribution of characteristics of single-span masonry arch bridges in the U.S. a) span,
b) width, c) rise, d) height of backfill above arch, e) total length, f) construction year where
𝑁𝐵 means number of bridges. ....................................................................................................... 12
Figure 6 : The elbow approach to determine optimal number of clusters for 326 bridge models. 14
Figure 7 : Element types and support conditions of the finite element model of single-span
masonry arch bridges. .................................................................................................................... 17
Figure 8 : Mesh refinement study to select optimal number of finite elements ............................ 21
Figure 9 : Peak ground acceleration with 2% probability of exceedance in 50 years in central and
eastern U.S. (USGS, 2016). ........................................................................................................... 22
Figure 10 : Peak ground acceleration with 10% probability of exceedance in 50 years in central
and eastern U.S. (USGS, 2016). .................................................................................................... 23
Figure 11 : Comparison of attenuation distance of earthquakes in eastern and western U.S.
(USGS, 2002). ............................................................................................................................... 24
Figure 12 : The distribution of the PGA for the Wen & Wu (2001) ground motions. .................. 26
Figure 13 : Seismic ground motion at angle of incident. ............................................................... 27
Figure 14 : Formation of a four-hinge mechanism at the arch vault when subjected to longitudinal
seismic loads. ................................................................................................................................. 28
vii
List of Figures (Continued) Page
Figure 15 : Rotation of spandrel wall when subjected to transverse seismic loads. ...................... 28
Figure 16 : Probabilistic Seismic Demand Model power model (Cornell et al., 2002). ................ 30
Figure 17 : Illustration of probabilistic seismic demand model in transformed space (Cornell et
al., 2002). ....................................................................................................................................... 31
Figure 18 : Example of fragility curve for type - 4 bridge category, representing the three damage
states for a) rotation of spandrel wall, and b) relative displacement between arch crown and
abutment. ....................................................................................................................................... 37
Figure 19 : Comparison of fragility curves generated for type - 1 category bridge for rotation of
spandrell wall using PSDM and MLE approach. .......................................................................... 38
Figure 20 : Geographical distribution of risk indices for 326 single-span masonry arch bridge for
limit state – 1 with 2% probability of exceedance in next 50 years .............................................. 41
Figure 21 : Geographical distribution of risk indices for 326 single-span masonry arch bridge for
limit state – 1 with 10% probability of exceedance in next 50 years. ........................................... 41

viii
LIST OF TABLES

Table Page
Table 1 : Geometric properties of 20 representative bridge types obtained using the k-means
clustering technique. ...................................................................................................................... 15
Table 2 : Sample time - acceleration records and their corresponding PGA and predominant
period for Wen & Wu ground motions. ........................................................................................ 25
Table 3 : Probabilistic seismic demand model equations for the 20 representative bridge types for
the rotation of spandrel wall. ......................................................................................................... 32
Table 4 : Probabilistic seismic demand model equation for the 20 representative bridge types for
the relative displacement of the abutment and crown. .................................................................. 33
Table 5 : Damage limit states for relative displacement between arch crown and abutment, and
rotation of spandrel wall collapse mechanisms. ............................................................................ 36
Table 6 : Fragility curve parameters of each damage limit state for rotation of spandrel wall. .... 38
Table 7 : Fragility curve parameters of each damage limit state for relative displacement between
arch crown and abutment............................................................................................................... 39

ix