Location
New York, New York
Date
14 Apr 2004, 4:30 pm - 6:30 pm
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
Meeting Name
5th Conference of the International Conference on Case Histories in Geotechnical Engineering
Publisher
University of Missouri--Rolla
Document Version
Final Version
Rights
© 2004 University of Missouri--Rolla, All rights reserved.
Creative Commons Licensing
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Document Type
Article - Conference proceedings
File Type
text
Language
English
Recommended Citation
Alostaz, Yousef; Hagh, Abdol; and Pecora, Jack, "Design and Construction of a Support of Excavation System for a Deep Cut-And-Cover Tunnel in Downtown Boston" (2004). International Conference on Case Histories in Geotechnical Engineering. 26.
https://scholarsmine.mst.edu/icchge/5icchge/session01/26
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.
