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Additional Subway Projects
Rio Piedras Contract No. AC-500083
Hato Rey, Puerto Rico
Project Description
This project consists of a Design-Build Contract for a subway section which includes
a mined station, a cut-and-cover station, mined running tunnels and cut-and-cover
line structures being built in San Juan, Puerto Rico.
Scope of Services
Lachel & Associates, Inc. was selected by the Tren Urbano to provide an
independent cost estimate for and evaluation of construction impacts arising from a
major Owner initiated change proposal. The change proposal increased the length of
the mined station by 15% (22.5 meters) and decreased the length and changed the
configuration of the adjacent cut-and-cover line structure section.
Lachel was responsible for preparing an independent, detailed cost estimate for the
changed work, reviewing the Contractor's detailed cost estimates, assisting in the
resolution of changed work quantities, preparing supplemental estimates as
negotiations progressed and providing support to the Owner during the negotiations.
Client
Tren Urbano
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Singapore Subway, Contracts 104 and 106
Republic of Singapore
Project Description
This project involved the geotechnical investigations and design for over 15,000
feet of 20-ft-diameter subway tunnel, three 60-ft-deep cut-and-cover stations and a
20-ft-diameter shaft.
Scope of Services
As the geotechnical and tunnel consultant for the contractor, Lachel & Associates,
Inc. was responsible for determining earth loads through soil, rock, sapprolites,
and faults; for evaluating earth loads for braced cuts in fluvial and marine deposits;
and for rock bolt support schemes in rock cuts. Using the above data, Lachel was also
responsible for the complete design of segmented tunnel liners, temporary and permanent
shaft support, all connecting cross passages and sumps and reinforced concrete walls
for braced cuts. Identification of potential problem zones resulted in relocation of
the subway alignment and avoidance of those zones, thus reducing the estimated
construction cost considerably.
Lachel was also responsible for water inflow studies and design of an instrumentation
program to efficiently predict excessive ground loss or other problems during
construction.
Client
Omicron Subway Contractors Ltd.
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