Design of Concrete Gravity Quay Walls - British Standards vs. Eurocode

摘要

Concrete blockwork quay walls are a common type of retaining structures used in marine and port facilities. Such gravity type retaining walls comprise of precast concrete blocks that are durable and well-suited for harsh marine environments. They have been widely used in the Gulf region in ports and more recently as part of the oil and gas offshore artificial islands infrastructure utilized during construction and operations stages. The main design reference of marine structures, including block work quay walls, is BS6349 which is based on Allowable Strength Design (ASD) method. In 2010, this code was updated based on Ultimate Limit State (ULS) or Load and Resistance Factor Design (LRFD) method in accordance with Eurocode. The updated code has not been applied in many marine projects (yet) and there are uncertainties about the effect of its application on the design. To investigate this effect, three designed gravity quay wall sections with heights ranging from 10.5 to 23.6 m were checked based on both ASD and ULS methods under static and seismic conditions. The stability analysis checks showed that the results are close for static condition but show significant differences under seismic conditions. A parametric study was conducted to investigate the effect of using Eurocode 8 on the design of gravity quay wall sections under different seismic conditions. The analysis indicated that Eurocode 8 (ULS) resulted in conservative sections compared to ASD methods of BS6349 for cases with surface Peak Ground Acceleration (a_(max)) higher than 0.1g – 0.15g. Results based on the Eurocode 8 design have been compared with USA codes and guidelines (AASHTO [2012], Caltrans [2014] and NCHRP 12-70 [2008]) which indicated that gravity structures designed using Eurocode 8 resulted in conservative sections in medium to high seismic areas. This study presents an assessment of the effect of using different codes on the design of gravity quay walls. Considering that the latest code versions are stipulated in the design, it is important for both Owners and Designers to appreciate the resulting effects on design and cost implications.