Development of Replacement Concepts for the Alaskan Way Seawall Seattle, Washington

摘要

The Alaskan Way Seawall is a unique structure located in Puget Sound,rnWashington. As the interface between the dense development of downtown Seattlernand the marine waters of Elliott Bay, its purpose is to provide wave and erosionrnprotection, as well as to retain fill for upland developments and transportation andrnutility corridors. While the seawall has served the city well over the past 70 years, itsrnmain structural support system, a timber relieving platform, has become vulnerable tornmarine borers. In addition, the design and location of the seawall make it vulnerablernto liquefaction induced failure in a strong earthquake. The loss of the seawall wouldrnthreaten not only the transportation facilities, the waterfront street, and the AlaskanrnWay Viaduct (part of the National Highway System - one of the two main northsouthrnhighway routes through Seattle), but also a regional utility corridor. Because ofrnthe importance of the structure and its vulnerabilities, many seawall replacementrnconcepts were studied before arriving at the current concept that combines soilrnimprovement with a new concrete face panel system.rnThis paper briefly describes the history of the seawall and summarizes thernimportant issues considered in the development of replacement concepts for thisrnunique and significant marine structure.