Fishbeck, Thompson, Carr & Huber, Inc.
Brick Tunnel Replacement
University of Michigan
IDEA 2011 Distribution Workshop
Introductions

Jeff Schumaker, P.E. – FTC&H
 Project

Manager and Structural Engineer
George MacKellar, P.E. – FTC&H
 Mechanical

Engineer
Mike Swanson – University of Michigan
 Owner
Brick Tunnel Replacement
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The Master Plan
The Challenges
Options
The Project
The Master Plan
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Deteriorating 80-year-old brick utility tunnel
Approximately 500 feet
North edge of the Diag
Tunnel
The Master Plan
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LPS (15 psi)
HPS (60 psi)
LPC
Compressed Air
DHWS/R
Testing and analysis
Surpassed useful
life
The Challenges


Park like setting
High profile area
The Challenges

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Running against and parallel with buildings
Under Kraus Building
Replacement Options
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Abandonment
In-place replacement
Conduit system through existing tunnel
New alignment – under sidewalk
Replacement Options

Abandonment
 Flow
Model
 Interconnects two legs
 Redundancy
 Reliability
 Maintenance
 Repairs
Replacement Options

In-Place Replacement
 Against
and under buildings
 Mature trees
 Sacrifice character of area
Replacement Options

Conduit System through existing tunnel
 Fill
tunnel with lean concrete
 Inexpensive vs. other options
 Excavation to repair would be difficult
Replacement Options

New Alignment Under Sidewalk
 Sidewalk
parallels current alignment
 Trees Trees Trees
 Cutting through a major thoroughfare
Replacement Options

Consulted with University of Michigan
Grounds Department
 Limit construction width to 13’-0”
 Tie up some tree limbs
Replacement Options
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Walkable tunnel
Utility trench
Conduit system
Replacement Options

Walk Tunnel
 Tall
and narrow
 Deep excavation
 Not ideal piping
configuration
 Access for maintenance
 Considered one-sided
forms
Replacement Options

Utility Trench
 Shallower
excavation
 Protection from
elements
 Removable top
 Add spare
condensate
Replacement Options

Conduit System
 Multi-pipe
system
 Shallow excavation
 Add spare
condensate
Life Cycle Cost Analysis
Option
First Cost
100-yr Life Cycle Cost
Walk Tunnel
$8.1M
$8.7M
Conduit System
$5.1M
$9.2M
Utility Trench
$6.4M
$12.7M
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Assumptions:
 Conduit system replacement in year 50
 Utility trench replacement in year 75
 Walk tunnel replacement in year 100
 Maintenance and replacement included
The Project

Existing vault on west end
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New vaults
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Two thrust blocks
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Pedestrian traffic flow
Existing Tunnel
Proposed Route
The Project

Tie-in point at East end
 Utility
 Tree
conflict
conflict
Existing Tunnel
Proposed Route
The Project
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Reinforce portion of brick tunnel from within
Existing Tunnel
Proposed Route
The Project
The Project
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Underpinning
 Vault
at existing tunnel
 Vault floor 6-foot below
Chemistry Building
foundation
Existing Tunnel
Proposed Route
The Project

Layout to accommodate accessories
 Drip
legs
 Expansion joints
 Valves
 Anchorage
Construction Photos
Construction Photos
Construction Photos
Construction Photos
Questions?
Thank you!

Jeff Schumaker, P.E. – FTC&H
(616) 464-3841 / [email protected]

George MacKellar, P.E. – FTC&H
(616) 464-3819 / [email protected]

Mike Swanson, C.E.M. – University of
Michigan
 (734)
763-3011 / [email protected]