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Abstract
Observations from closely-spaced seismograph arrays since the late 1970’s have shown that earthquake ground accelerograms measured at different locations within the dimensions of typical large engineered structures are significantly different. This has led to considerable research in the last two decades on modeling spatially varying earthquake ground motion (SVEGM) and on determining its effect on the seismic response of large structures such as long span bridges, pipelines, dams…etc.
The objective of current research is to examine the effect of spatial variability of earthquake motion on the response of long span bridges, and hence comparing the response to that computed using uniform earthquake ground motion on bridges to shed light on features of the seismic response characteristics of these long span bridges. The present study will be performed on cable stayed bridges as examples on long span bridges.
The thesis will include five chapters as follows:
Chapter 1 : Introduction
This chapter contains introduction and thesis organization
Chapter 2 : Literature review
This chapter contains literature review for cable stayed bridges, the effect of spatial variability of earthquake ground motion on the response of bridge structures and different approaches to calculate this effect on such long span bridges.
Chapter 3 : Bridge modeling and theoretical investigation
This chapter contains description of the analytical model of Suez Canal cable-stayed bridge which is used as a case study in the theoretical investigation. In this chapter, the analyzed bridge is presented and acting ground motions of El Centro earthquake are derived from accelerations records .
Chapter 4 : Results of analysis under uniform and non-uniform ground motion
This chapter contains the parametric study under different speeds of earthquake waves; the parametric study includes the ideal case of the bridge and assumes broken cables as well as different deck to pylon stiffness. The results of ideal case of the bridge under uniform effect of ground motion analysis is presented and comparisons of different parametric study cases at selected location of bridges under examination are charted, in addition discussion of the causes of these differences in each case.
Chapter 5 : Conclusions and recommendations
This chapter contains summary, conclusions and recommendations for future research on this type of long span bridges against earthquakes.