Seismic vulnerability assessment of pile-supported wharves using fragility curves

Abstract

In this study, the seismic vulnerability of a pile-supported wharf is assessed. Due to common lack of empirical data, the analytical fragility curves are developed using the results of the dynamic analysis of wharf subjected to the different time histories. Fragility curves are developed considering three engineering demand parameters, including displacement ductility factor (m d ), differential settlement between deck and behind land and normalised residual horizontal displacement (NRHD). A sensitivity analysis using both the first-order second-moment method and the tornado diagram analysis is then carried out to evaluate the effects of uncertainties associated with geotechnical parameters in the seismic performance of the wharf. Adopted fragility curves are useful to seismic risk assessment. They can also be used to optimise wharf-retrofit methods. The results of sensitivity analysis demonstrate that uncertainties associated with the permeability of hydraulic placed sand fill contribute most to the variance of both NRHD and m d . While in the case of differential settlement, the friction angle of rock fill contributes most to the variance.

The influence of the soil constitutive models on the seismic analysis of pile-supported wharf structures with batter piles in cut-slope rock dike

“…The JCB01 model selected from a series of centrifuge models carried out at the Center for Geotechnical Modeling of California University (UC Davis) was chosen for the study. [3,10,26,28,29] This model has a configuration of a typical wharf of Western United States ports. It consists of a deck supported by seven rows of vertical piles including two pairs of batter piles, embedded in cut slope rock dike overlaid an embankment of loose sand.…”

“…For the rockfill, an artificial cohesion of 15 kPa and a dilation angle of 0° were applied. [3] The input parameters of soil used for the Mohr-Coulomb model are summarized in Table 1, and for more details refer to Boland et al, [10] McCullough, [3] Heidary-Torkamani et al [28,29] and Amirabadi et al [26] The dry mass density was 1633 kg/m 3 , 1522 kg/m 3 and 1611 kg/m 3 respectively for dense sand, loose sand and rockfill. The material damping of soils was simulated with 5% of damping ratio (Rayleigh damping).…”

“…e input parameters used in the modeling of the structural elements are presented in Table 4. For more details, refer to dies by Boland et al, [10] McCullough, [3] Heidary-Torkamani et al, [28,29] and Amirabadi et al [26] (23)…”

“…Recently, a large volume of research works used seismic fragility curves as a useful tool to evaluate the seismic performance of pile-supported wharves. [23][24][25][26][27][28][29][30] Several port structures use batter piles to provide lateral resistance and to limit deflections from lateral loads, such as ship berthing and seismic loads. In the past, engineers contest the use of batter piles due to the poor performance under earthquake, caused by the lack of proper design of the batter piles head connections.…”

“…Razavi et al [33] presented some batter pile damages during severe earthquakes, and performed seismic analysis of a typical pier with and without batter piles. Heidary-Torkamani et al [28,29] developed the seismic fragility curves of wharves with batter piles, considering different engineering demand parameters (EDPs) for each damage state, and also performed a sensitivity analysis in order to evaluate the influence of geotechnical parameter uncertainties in the seismic performance of the wharves. Li et al [34,35] ) studied dynamic response characteristics and failure process of vertical and batter pile-supported wharf structure, established on the same conditions, and subjected to two different earthquake levels.…”