Title: Displacement Demands and Shear Key Forces in Pile-Supported Marginal Wharves with Strong Lateral-Torsional Coupling

Author(s): Carlos Blandon, Jose I. Restrepo, and Omar Jaradat

Publication: Symposium Paper

Volume: 295

Issue:

Appears on pages(s): 1-18

Keywords: Dynamic Magnification Factor, Non-linear response, Marginal wharves, Performance-based seismic design, Shear keys, Torsion.

DOI: 10.14359/51686350

Date: 10/4/2013

Abstract:
Pile-supported marginal wharves have geometrical characteristics that make them prone to torsional response when subjected to earthquake induced inertial forces. Because of expected early system non-linear response due to the soil-structure interaction, lateral displacement demands on the piles cannot readily be estimated from conventional elastic modal response spectrum analyses and modal combination techniques. These displacement demands may be obtained using non-linear time-history analysis. Nevertheless, modeling the non-linear response of the wharf is still impractical in many design offices. For this reason, simple approximate methods that can estimate the critical pile displacement demand as the spectral displacement corresponding to a predominant translational (transverse) mode natural period of the wharf multiplied by a Displacement Magnification Factor (DMF) is adequate for design purposes. This paper revisits the earlier work of Benzoni and Priestley (2003) and computes, through non-linear time-history analysis, DMFs of short, long and linked segment wharves. Furthermore, the paper also reports shear key forces observed in the non-linear analyses of linked segment wharves. Finally, equations are proposed for calculating the DMFs and to estimate the forces for the design of shear keys.