Location

New York, New York

Session Start Date

4-13-2004

Session End Date

4-17-2004

Abstract

This paper presents the analysis, design, implementation and construction of a Value Engineering Cost Proposal (VECP) for the support of excavation system for parts of the underground Central Artery Tunnel in downtown Boston. The excavation varies between about 130 ft and 240 ft in width and between 60 ft and 100 ft in depth. The typical structure of the tunnel consists of soldier pile tremie concrete (SPTC) walls, roof girders with a cast-in place (CIP) concrete slab and a CIP invert slab. The SPTC walls, constructed using the bentonite slurry technique, act as the temporary earth-support structure as well as the permanent walls of the tunnel. The walls are temporarily braced during the excavation prior to the installation of the roof girders and the invert slabs. This support of excavation (SOE) scheme was the target of the VECP. The VECP was conceived to save both time and money over the original scheme presented in the contract documents, which was based on a beam on elastic foundation method of analysis to design the walls and determine line loads for bracing design. The crucial element of the VECP was to use a finite element analysis method to reanalyze the walls with fewer bracing levels. This analysis yielded lower line loads compared to the original design. The paper traces the steps leading to the implementation of the VECP, including the proposal and preliminary design, the cost and schedule negotiations with the owner, their representatives and the designer of record, the analysis and design submittals and, finally, the construction and performance of the system.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

Fifth Conference

Publisher

University of Missouri--Rolla

Publication Date

4-13-2004

Document Version

Final Version

Rights

© 2004 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

Share

 
COinS
 
Apr 13th, 12:00 AM Apr 17th, 12:00 AM

Design and Construction of a Support of Excavation System for a Deep Cut-And-Cover Tunnel in Downtown Boston

New York, New York

This paper presents the analysis, design, implementation and construction of a Value Engineering Cost Proposal (VECP) for the support of excavation system for parts of the underground Central Artery Tunnel in downtown Boston. The excavation varies between about 130 ft and 240 ft in width and between 60 ft and 100 ft in depth. The typical structure of the tunnel consists of soldier pile tremie concrete (SPTC) walls, roof girders with a cast-in place (CIP) concrete slab and a CIP invert slab. The SPTC walls, constructed using the bentonite slurry technique, act as the temporary earth-support structure as well as the permanent walls of the tunnel. The walls are temporarily braced during the excavation prior to the installation of the roof girders and the invert slabs. This support of excavation (SOE) scheme was the target of the VECP. The VECP was conceived to save both time and money over the original scheme presented in the contract documents, which was based on a beam on elastic foundation method of analysis to design the walls and determine line loads for bracing design. The crucial element of the VECP was to use a finite element analysis method to reanalyze the walls with fewer bracing levels. This analysis yielded lower line loads compared to the original design. The paper traces the steps leading to the implementation of the VECP, including the proposal and preliminary design, the cost and schedule negotiations with the owner, their representatives and the designer of record, the analysis and design submittals and, finally, the construction and performance of the system.