SEISMIC SOIL-STRUCTURE INTERACTION BEHAVIOR OF PILE-SUPPORTED WHARF SYSTEMS ON LIQUEFIABLE SOILS

UNDER 3-D EXCITATION

Caner Gülenç

(Thesis Supervisors: Prof. Eser Çaktı & Co- Supervisor: Prof. M. Nuray Aydınoğlu)

ABSTRACT

The procedures currently used in the analysis and design of pile-supported wharf structures are inadequate to consider the important features of the systems under seismic excitation. Highly sophisticated analysis models employed in literature neglect the seismic excitation in longitudinal direction, while design approaches roughly incorporate this aspect but fail in accurate modeling of soil-structure interaction (SSI) effects. Despite widespread use of very long multi-segmented wharves in marine construction practice, seismic analysis of these systems is generally overlooked. It is likely that such long structures exhibit varying soil stratification along the embankment in the longitudinal direction.

In this regard, three-dimensional soil-structure interaction models are developed for multi-segmented wharf systems situated on liquefiable soil conditions, addressing a realistic engineering challenge. The analyses of these systems are performed under three-dimensional seismic excitation and the outputs are meticulously processed to clearly demonstrate the outcomes. Finally, the findings are presented in proper order.

The results indicate that SSI modeling and soil liquefaction play a crucial role in the seismic behavior of wharves. The impact of longitudinal excitation in liquefiable soil conditions significantly affects both soil and structural responses. The torsional response of structural systems is negligibly small. Analysis of multi-segmented wharf systems may only be required when varying liquefiable soil layers exist along the embankment.

This study is expected to be a pioneering effort in the field of marine geo-structural engineering, potentially providing a base for the performance-based analysis and design of pile-supported wharf systems in the near future.