COMBINED SEISMIC AND SCOUR VULNERABILITY ASSESSMENT OF STEEL MOMENT RESISTING FRAME STRUCTURE USING CURSORY SATELLITE IMAGERIES

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COMBINED SEISMIC AND SCOUR VULNERABILITY ASSESSMENT OF STEEL

MOMENT RESISTING FRAME STRUCTURE USING CURSORY SATELLITE

IMAGERIES

By

RAUNAK SHUKLA

A design paper submitted in partial fulfillment of the requirements for the

Master of Science

Major in Civil Engineering

South Dakota State University

2015

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COMBINED SEISMIC AND SCOUR VULNERABILITY ASSESSMENT OF STEEL

MOMENT RESISTING FRAME STRUCTURE USING CURSORY SATELLITE

IMAGERIES

This design paper is approved as a creditable and independent investigation by a

candidate for the Master of Science in civil engineering degree and is acceptable for meeting

design paper requirement for this degree. Acceptance of this design paper does not imply that

the conclusion reached by the candidate is necessarily the conclusion of the major

department.

Junwon Seo, Ph.D., P.E. Date

Design Paper Advisor

Nadim Wehbe, Ph.D., P.E Date

Department Head

Civil & Environmental Engineering

Dean Graduate School Date

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ACKNOWLEDGMENTS

I would like to gratefully acknowledge the advice, support, and encouragement provided

by Dr. Junwon Seo throughout the pursuit of my master’s degree. His experience and

knowledge have brought me a great educational experience. This paper would not be

completed without his support and guidance.

Deep gratitude is extended to my Mother, brother Rahul and my Uncle Yogendra Nath

Tripathi for the ceaseless love and unconditional support they have provided throughout the

course of my education.

I would also like to express special thanks to Abdullah, Nitin, Marius and Burte for their

assistance and friendship, as well as for their willingness to share their considerable

knowledge.

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TABLE OF CONTENT

TITLE Page

List of Figures……………………………………………………………………………………………………….. v

List of Tables…………………………………………………………………………………………………………. vi

ABSTRACT………………………………………………………………………………………………………….. vii

1 INTRODUCTION……………………………………………………………………………………………….. 1

1.1 Background…………………………………………………………………………………………….1

1.2 Objective………………………………………………………………………………………………..1

1.3 Scope of Work……………………………………………………………………………………….. 2

1.4 Outline……………………………………………………………………….… 2

2 LITERATURE REVIEW……………………………………………………………………………………… 4

2.1 Estimation of Structure Dimensions………………………………………………………….. 4

2.2 Seismic Vulnerability Assessment……………………………………………………………. 4

2.3 Soil-Structure Interaction (SSI)……………………………………………………………….. 5

2.4 Fragility Curves…………………………………………………………………………………….. 6

3 SATELLITES IMAGE-BASED BUILDING CONFIGURATION…………………………… 7

3.1 Building Selection…………………………………………………………………………………. 7

3.2 Building Configuration………………………………………………………… 8

3.3 Validation of Building Configuration…………………………………………. 9

4. SEISMIC SIMULATION……………………………………………………………………………………. 10

4.1 Modelling Approach………………………………………………………………………………. 10

4.2 Seismic Ground Motion Parameters…………………………………………………………. 15

4.3 Soil Structure Interaction for Building Structure………………………………………… 16

4.3.1 Introduction……………………………………………………………………………… 16

4.3.2 Brookings City & County Building…………………………………………….. 20

4.3.3 Foundation Conditions………………………………………………………………. 20

4.3.4 Development of Foundation Springs and Dashpots……………………….. 21

4.4 Synthetic Ground Motion………………………………………………………………………… 27

4.5 Inter-story Drift…………………………………………………………………………………….. 29

5 FRAGILITY CURVE………………………………………………………………………………………….. 31

5.1 Damage Indices………………………………………………………………….31

5.2 Procedure………………………………………………………………………. 31

5.3 Samples of Fragility Curves…………………………………………………………………….. 32

6 PARAMETRIC STUDIES……………………………………………………………………………………. 37

7 SUMMARIES, CONCLUSIONS AND FUTURE WORK……………………………………….. 41

APPENDIX…………………………………………………………………………………………………………… 43

REFRENCES ……………………………………………………………………………………………………….. 50

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LIST OF FIGURES

Figure 3-1: Brookings City & County Government Center Building Picture:

(a) Front View (b) Side view…………………………………………………………………………. 8

Figure 3-2: Satellite Image………………………………………………………………………………………..9

Figure 4-1: Brookings City & County Government Center Building Plan –

Ground Floor and Second floor……………………………………………………………………… 10

Figure 4-2: Brookings City & County Government Center Building Plan – First Floor…… 11

Figure 4-3: Brookings City & County Government Center Building Plan – Roof…………… 11

Figure 4-4: Three-dimensional models of Brooking city & county building

with fix support…………………………………………………………………………………………….12

Figure 4-5: First five modes shapes……………………………………………………………………………13

Figure 4-6: Response Spectrum Curve………………………………………………………………………. 15

Figure 4-7: Three Dimensional Soil Structure Interaction………………………………… 22

Figure 4-8: Representation of four springs removed for joint effect of seismic and scour… 24

Figure 4-9: Representation of nine springs removed for joint effect of seismic and scour… 25

Figure 4-10: Representation of seventeen springs removed for joint effect of

seismic and scour…………………………………………………………………………………………. 25

Figure 4-11: Representation of twenty seven springs removed for joint effect

of seismic and scour………………………………………………………………………………………26

Figure 4-12: Representation of forty nine springs removed for joint effect of

seismic and scour…………………………………………………………………………………………. 26

Figure 4-13: X-Component Spectral Acceleration Vs Time…………………………………………. 28

Figure 4-14: Y Component Spectral Acceleration Vs Time…………………………………………. 28

Figure 4-15: Z Components Spectral Acceleration Vs Time Graph………………………………. 29

Figure 4-16: Inter-story drift …………………………………………………………………………………….29

Figure 5-1: Fragility Curve XYZ-Component for Fix support……………………………………….33

Figure 5-2: Fragility Curve XYZ-Component for spring support………………………………….. 33

Figure 5-3: Fragility Curve XYZ-Component for Soil-Structure interaction for

the four springs removed……………………………………………………………………………… 34

Figure 5-4: Fragility Curve XYZ-Component for Soil-Structure interaction for

the nine springs removed………………………………………………………………………………. 34

Figure 5-5: Fragility Curve XYZ-Component for Soil-Structure interaction for

the seventeen springs removed……………………………………………………………………… 35

Figure 5-6: Fragility Curve XYZ-Component for Soil-Structure interaction for

the twenty seven springs removed………………………………………………………………….. 35

Figure 5-7: Fragility Curve XYZ-Component for Soil-Structure interaction for

the forty nine springs removed………………………………………………………………………..36

Figure 6-1: Fragility curves of performance levels of each parameter: (a) IO;

(b) LS; and (c) CP……………………………………………………………………………………….. 38

Figure 6-2: FEMA structural performance levels (IO) XYZ-component……………………….. 39

Figure 6-3: FEMA structural performance levels (LS) XYZ-component……………………….. 39

Figure 6-4: FEMA structural performance levels (CP) XYZ-component……………………….. 40

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LIST OF TABLES

Table 4-1: Modal Participation Mass Ratio………………………………………………… 14

Table 4-2: Values of Shear Wave Velocity and Shear Modulus Reduction for various

Site Classes and Shaking Amplitudes (ASCE, 2010; FEMA, 2009)…………………….17

Table 4-3a: Elastic Solutions for static stiffness for rigid footings at the ground surface

(NEHRP, 2012)…………………………………………………………………………………………… 17

Table 4-3b: Embedment Correction Factor for Static Stiffness of Rigid Footings

(NEHRP, 2012)…………………………………………………………………………………………… 18

Table 4-4a: Dynamic Stiffness Modifiers and Radiation Damping Ratios for Rigid

Footings (NEHRP, 2012)………………………………………………………………………………. 19

Table 4-4b: Dynamic Stiffness Modifiers and Radiation Damping Ratios for Embedded

Footings (NEHRP, 2012)………………………………………………………………………………. 20

Table 4-5: Summaries of Effective Profile Depth and Average Effective Profile

Velocities for the Brookings City & County Building………………………………………. 22

Table 4-6: Calculation of Shallow Foundation stiffness and damping parameters

for the Brookings City & County Building……………………………………………………….23

Table 4-7: Ground Motion peak ground accelerations (PGAs)……………………………………… 27

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ABSTRACT

COMBINED SEISMIC AND SCOUR VULNERABILITY ASSESSMENT OF STEEL

MOMENT RESISTING FRAME STRUCTURE USING CURSORY SATELLITE

IMAGERIES

RAUNAK SHUKLA

2015

Given the majority of the steel moment frame structures located in a region classified as the

low seismically active and high flood prone area, vulnerability assessment on such structures

subjected to combined effects of seismic and scour loads is needed. This paper focuses on

combined seismic and scour vulnerability assessment of a three-story existing steel moment

resisting frame structure in the Midwestern region of the United States. The structure

dimensions were initially measured using satellite imageries of the selected structure via

commercial scale map tools and calibrated with those from the design plan having beam and

column details which were detained from the building owner. With all the structural

information, a finite element model of the structure with soil springs reflecting the soil-

structure interaction behaviors during an earthquake was created through commercially

available finite element software, SAP2000. To account for joint seismic and scour risk, a

total of forty eight synthetic ground motions having different spectral accelerations (Sa) were

used, and the soil springs were progressively removed. Numerous nonlinear time history

analyses reflecting the effects of scour effects by adjusting the removed soil spring number

was conducted to determine peak inter-story drifts (PISDs) of the structure. Federal

Emergency Management Agency (FEMA)-based three performance levels (i.e., immediate

occurrence, life safety, and collapse prevention) were used for creation of joint seismic and

scour vulnerability functions. Significant findings show that the joint seismic and scour

vulnerability of the structure increased as they become more damaged due to the reduced

resistant forces from the removal of soil springs over a broad spectrum of Sa.

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1 INTRODUCTION

1.1 Background

The seismic vulnerability assessment of existing steel building structures is one of the

priorities for many earthquake engineers and researchers (Plasticier, 2007) to help

probabilistically measure their structural vulnerability and to establish systematic earthquake

mitigation planning. Steel moment-resisting frame structures have been widely used in all

seismic zones because of favorable mass-to-stiffness ratio and ductility which enhances

energy absorption capacity (Sarno, 2002). Typically, steel frame structures are divided into

three types: moment resisting frame (MRF) structure, concentrically braced frame (CBF)

structure, and eccentrically braced frame (EBF) structure. They exhibit different structural

behaviors with respect to stiffness, strength and ductility of an earthquake (Sarno, 2002). In

fact, past earthquakes, including 1994 Northridge earthquake in the United States, 1995

Hyogoken-Nanbu earthquake in Japan and 1999 Chi-Chi earthquake in Taiwan, arouse

unexpected significant damage to certain structural components of low- to mid-rise steel

framing structures (Sarno, 2002). The damages were widespread and extensive throughout

residential or commercial building structures (Sarno, 2002). Specifically, Northridge

earthquake caused the most damage to low-rise steel frame structures with no casualties

(Mahin, 1998). The past earthquake demonstrated that several structural components, such as

moment connections, have a significant influence on seismic performance, resulting in

associated structural vulnerability of such structures. Hence, some provisions related to

seismic resistance of moment connections, including Structural Engineers Association of

California (SEAOC), Federal Emergency Management Agency (FEMA) regulations, and the

ASCE 7-10 design standard, are included.

The majority of the steel moment frame structures located in a region classified as the low

seismically active and high flood prone area, vulnerability assessment on such structures

subjected to combined effects of seismic and scour loads is needed.

1.2 Objectives

The objective of this paper is to evaluate the vulnerability assessment of a three-story

existing steel moment frame structures located in Midwestern region of the United States,

subjected to combined effects of seismic and scour loads. This evaluation was accomplished

by performing numerous nonlinear time history analyses using computational finite element

analysis software. Specific tasks are made to achieve the objective as follows:

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Measure the dimension (height, length & width) of the selected structure using

cursory satellite imageries.

Evaluate soil-structure interaction of the structure.

Evaluate seismic performance of the structure subjected to forty eight ground

motions.

Develop combined seismic and scour vulnerability of fragility curves for the

structures.

1.3 Scope of Work

The structure dimensions were measured using their satellite imageries via

commercial scale map tools and calibrated with those obtained from the design plan having

beam and column details. Three dimensional finite element models were created using

commercially available finite element software SAP2000. To account for different seismic

intensities of the building, a total of forty eight ground motions having different peak ground

accelerations (PGAs) ranging from 0.1 g to 1.2 g were used. Structure was modeled for soil

flexibility. To consider soil-structure interaction behavior, both the effect of soil-structure was

taken into account to evaluate the stiffness in translational and rotational direction. To

account for joint seismic and scour risk, the soil springs were progressively removed.

Nonlinear time history analysis was conducted to determine inter-story drifts (ISDs) of the

structure subjected to forty eight ground motions. Three performance levels, e.g., immediate

occurrence, life safety and collapse prevention were considered for seismic fragility analysis.

Fragility curves were developed using commercial method.

1.4 Outline

This paper focuses on measurement of dimensions using cursory satellite

imageries and combined seismic and scour vulnerability assessment of a three-story

existing steel moment resisting frame structure in the Midwestern region of the United

States.

Chapter 2 describes the previous studies on estimation of structure dimension, seismic

vulnerability assessment, soil structure interaction, development of fragility curves.

Chapter 3 provides building dimension measurement using cursory satellite imageries.

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Chapter 4 provides an overview of seismic vulnerability assessment and soil-structure

interaction to account for the foundation flexibility.

Chapter 5 describes three performance levels based on federal emergency management

agency (FEMA) which were considered in this study for the creation of joint seismic and

scour vulnerability functions and explains the procedure for creating fragility curves.

Chapter 6 describes the comparison of FEMA performance levels with spectral acceleration

median range to account for the joint seismic and scour effect.

Chapter 7 provides a summary, conclusion remark and recommendation for future research.

Appendix provides the tables of Mass participation ratio and inter-story drift for all the cases

considered in combined effect of seismic and scour loads.

A list of references cited from the body of literature review is provided at the end of this

paper.

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2 LITERATURE REVIEW

This chapter reviews information about previous studies on structure dimension

determination using cursory satellite imageries, seismic vulnerability assessment, soil-

structure interaction, and development of fragility curves.

2.1 Estimation of Structure Dimensions

The vulnerability assessment of the structure can be measured using satellite

imageries. High-resolution satellite imageries were used to estimate damage for the Bhuj,

India during 2001 earthquake (Chiroiu L., 2001). The study provided the fast loss estimation

of physical damage and human casualties. During past few years measurement of structure

configurations using satellite images has gained lot of attention (Meng, 2009). Building

extraction requires high-resolution satellite images with a resolution higher than 5meters (Jin

and Davis, 2005). To identify buildings by using structural, contextual and spectral

information a 1-meter resolution satellite imagery is needed (Jin and Davis, 2005).

Morphological building detecting method was employed to identify building configuration by

gradually removing non-building pixels (Meng, 2009). A methodology was evaluated to

determine the height and position of buildings in dense residential areas by using IKONOS

stereo imagery (Shaker, 2011). An automated extraction of buildings by high-resolution

satellite imagery with different rooftops utilizes structural and spectral information by using

Artificial Neural Networks (Lari, 2007). Building reconstruction from a single digital surface

model (DSM) was usually monitored based on a stochastic approach (Lafarge, 2007).

Reconstruction of structures involved assembling simple urban structures extracted from a

library of 3D parametric models, this method was well adapted to data of average quality

such as high-resolution satellite imageries. Still need further work on estimation of structure

configuration.

2.2 Seismic Vulnerability Assessment

A proper evaluation of the seismic risk in existing buildings is a necessary step in

order to recognize the most critical areas. A number of studies on the seismic risk of steel

moment frame structure have been carried out. The seismic vulnerability assessment of steel

moment resisting frames was studied to determine the impact of higher importance factors

and stringent drift limits (Jeong H. S. et al., 2014). The effects of the risk categories for the

structural periods and the seismic force demand was investigated. The results show that the

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risk category IV had a decreased in its period by 0.5 to 0.8 and show an increase in strength

by a factor of 1.5 to 3.2. The seismic behavior of weak axis column-tree connection used in

steel moment resisting frames were investigated (Keunyeong et al., 2015). The result showed

that the weak column axis connection with reduced beam section was better than the trapped

connections. The seismic vulnerability assessment of a 20-story steel moment resisting frame

structure was conducted to evaluate the performance based on ASCE 7-10. The result showed

that the structure met the code requirements (FraAnnika Mathiasson and Ricardo A. Medina.,

2014). A linear dynamic analysis and nonlinear pushover analyses on a existing irregular 8-

story steel building (Hosseini et al.,). Result showed that for multiple excitations the value of

responses is very high and nonlinear behavior is different for the corner columns then what is

mentioned in recommendation. Erduran, (2010) performed nonlinear response history

analysis to evaluate the multi-intensity seismic response of code-designed conventional and

base-isolated steel frame building. Three-story braced frame building was used. The results of

structural response analysis showed that the isolated structure is more superior to

conventional structures.

2.3 Soil-Structure Interaction (SSI)