**Author details**

Wael A. Zatar\* *College of Information Technology and Engineering, Marshall University, Huntington, West Virginia, USA* 

<sup>\*</sup> Corresponding Author

Issam E. Harik *Department of Civil Engineering, University of Kentucky, Lexington, Kentucky, USA* 

#### **Acknowledgement**

The support of the Federal Highway Administration, Transportation Cabinet of the Commonwealth of Kentucky, and Kentucky Transportation Center is gratefully acknowledged.

#### **14. References**

228 Earthquake Engineering

Transportation report [11].

appropriate actions.

**Author details** 

Corresponding Author

*College of Information Technology and Engineering, Marshall University, Huntington, West Virginia, USA* 

Wael A. Zatar\*

 \*

**13. Summary and conclusions** 

One complete example of the calculation procedures to identify the seismic risk of a bridge embankment in McCracken County is provided in Zatar and Harik [16]. Similar procedures are followed in order to identify the seismic risk of all the 127 bridge embankments in all seven counties along I-24 in western Kentucky. Full details and results of the ranking and prioritization of the bridges along I-24 in western Kentucky are provided in the Kentucky

This document describes the authors' efforts in addressing the technical component of embankment prioritization, and is well suited to a reliability-based model for seismic risk assessment. A methodology is presented to quickly conduct seismic assessment and ranking of bridge embankments in order to identify and prioritize those embankments that are highly susceptible to failure. The step-by-step methodology is provided in a flowchart that

The proposed ranking model is useful for a quick sensitivity assessment of the effect of various site conditions, earthquake magnitudes, and site geometry on possible movement of a designated embankment. The methodology was applied on 127 bridge embankments on a priority route in western Kentucky in order to identify and prioritize the embankments, which are susceptible to failure. Data regarding soil types and depth of bedrock is not available for the majority of the 127 bridge embankments of I-24 in western Kentucky. However, obtaining detailed geo-technical investigations and sophisticated models are typically limited because of the associated cost and effort. The methodology outlines possible approaches to predict the unavailable information regarding a bridge embankment site. The embankment geometry, material, type of underlying soil, elevation of the natural ground line, and upper level of bedrock are the variables of each embankment. Seismic slope stability capacity/demand ratio, displacement, and liquefaction potential of each bridge embankment along I-24 in western Kentucky are estimated. Three categories are presented to identify the failure risk and provide a priority list of the embankments. The seismic vulnerability during projected 50-year, 250-year, and 500-year seismic events are obtained and the associated seismic performance criteria are examined. An example of seismic ranking and prioritization of bridge embankments along I-24 in McCracken County in western Kentucky is presented. The priority list enables decision makers to take

is specifically designed to ensure minimal effort on behalf of the engineer/researcher.


[13] Zatar, W. A., and Harik, I. E., "Bridge embankments: Part II - Seismic risk of I-24 in Kentucky." *ASCE Journal of Performance of Constructed Facilities*, June 2008.

**Chapter 9** 

© 2012 Liu and Wang, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2012 Liu and Wang, licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**Finite Element Analysis of Cable-Stayed Bridges** 

**with Appropriate Initial Shapes Under Seismic** 

**Excitations Focusing on Deck-Stay Interaction** 

In the last several decades, cable-stayed bridges have become popular due to their aesthetic appeal, structural efficiency, ease of construction and economic advantage. This type of bridge, however, is light and flexible, and has a low level of inherent damping. Consequently, they are susceptible to ambient excitations from seismic, wind and traffic loads. Since the geometric and dynamic properties of the bridges as well as the characteristics of the excitations are complex, it is necessary to fully understand the mechanism of the interaction among the structural components with reasonable bridge shapes, which is used to provide the essential information to accurately calculate the

In the previous studies of bridge dynamics, the responses of a cable-stayed bridge can be categorized into global, local and coupled modes [1]. The global modes are primarily dominated by the deformations of the deck-tower system with the quasi-static motions of the stay cables; the local modes predominantly consist of the stay cable motions with negligible deformations of the deck-tower system; the coupled modes have substantial contributions from both the deck-tower system and stay cables. Since the towers are usually designed with a high rigidity to obtain an adequate efficiency of the system, the significant tower deformations do not occur in the lower modes sensitive to the ambient excitations [2]. Consequently, the coupled modes are considered to be dominated by the deck-stay interaction, while the contribution from the towers can be neglected. Numerical approaches based on the finite element method have been widely used to investigate the deck-stay interaction. The finite-element models of a cable-stayed bridge can be classified into two categories [1]: the one-element cable system (OECS), in which each stay cable is represented

dynamic responses of the bridges under the complicated excitations.

Ming-Yi Liu and Pao-Hsii Wang

http://dx.doi.org/10.5772/48440

**1. Introduction** 

Additional information is available at the end of the chapter

[14] Pflazer, W. J. (1995). "Use of existing geotechnical data to supplement site investigations." *Proceedings of the Ohio River Valley Soils Seminar XXVI*, ASCE Kentucky Geotechnical Engineers Group, Clarksville, Indiana.
