Bridge over BNSF Railroad
7 km East of Windham - East
Bridge Replacement Project Using
Accelerated Bridge Construction
Project Location
Existing Bridge
o 3-Span Concrete Tee Beam
o 123 Feet Long
o 28 Feet Wide
Approach Looking Southeast
Profile Looking Southwest
Design Parameters
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National Highway Route
2500 vehicles per day (23% Trucks)
Major truck route between Great Falls and Billings
US Air Force Missile Route
Grain Elevator in Moccasin
BNSF Railroad Crossing
Accident cluster at bridge
New Bridge
Requirements
New width = 40 feet
Increased railroad lateral clearance
Increased railroad vertical clearance
Avoid existing foundations (timber piles)
Minimize grade raise to catch slopes on existing
approaches – avoid sliver fills and new R\W
o Minimize traffic disruptions
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What are our options?
o New Bridge on Offset Alignment
o New Bridge on same alignment using On-site
Detour
o New Bridge on same alignment using Phase
Construction
o New Bridge on same alignment using Off-site
detour and ABC
Could Accelerated
Construction work
here??
o How long can we shut down bridge site?
o How quickly can we build a new bridge?
o How much building can be completed before with
existing bridge in place?
o Is there a reasonable detour route?
Possible detour route
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Secondary Highways – wide shoulders / flat slopes
Similar detour length for thru-traffic
Detour through town of Hobson – school crossing
At-grade RR crossing in Hobson
Many local detours possible (County Roads)
ABC Planning Efforts
o Contacts with
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Town of Hobson - Mayor
Hobson School
County Commissioners
Trucking Industry – grain elevator
Air Force Base
BNSF Railroad
Road User Cost Calculations
Preliminary ABC Ideas
Contract Time Estimates
Local Events
– Hay Days –
Utica Montana
What can we accelerate?
What portion of construction takes the most time?
o Foundation construction – 4 days/shaft or 4
piles/day
o Drilled Shaft testing – 14 days before testing /
longer if problems are encountered
o Forming bent caps – 3 days each
o Curing bent caps – 15 days per project
o Deck forming – 20 days up to 300 feet
o Deck curing and sealing – 28 days
Allowing for some overlap……80 days for major items
Potential Solutions
o Foundations
o What can we do while traffic is on existing bridge?
o What foundation types will work?
o Forming and curing bent caps
o What cast-in-place can be done while traffic is on existing bridge?
o Precast end and intermediate caps?
o Deck forming and curing
o Full-depth precast deck panels
o Partial-depth
o Stay-in-place Forms
Divided Work Into Stages
o What could be completed before detouring traffic
o What would be accelerated while traffic is on
detour route
o What work could be done after traffic is moved
back on new bridge
Work Prior to Detouring Traffic
Drilled 4 shafts outside the bridge limits and
behind the existing intermediate bents.
Cast struts/crash wall on top of and between shafts
Cast walls on top of struts
Day 1
Traffic on Detour
o Removed span 2 deck and beams
o Removed span 3 deck
Day 2
o Removed span 3 beams
o Removed bent 3 and 4
o Removed span 1 deck
Day 3
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Bent 4 – drove piles, formed and placed cap
Bent 3 – Set cap and placed closure
Removed span 1 beams
Removed bents 1 and 2
Precast
Pier Cap
Day 4
o Bent 2 – Set cap
o Bent 1 – drove piles
Day 5
o Bent 2 – placed closure
o Bent 4 –formed and placed cap
Day 6
o Span 3 – Set girders and deck panels
Day 7
o Sunday – no work
Day 8
o Span 2 – Set girders and deck panels
Day 9
o Span 1 – Set girders and half the deck panels
Day 10
o Span 1 – Set remaining deck panels
o Began forming closure pours
Day 11
o Bents 1 & 4 – Formed and placed backwalls
o Formed deck panel closure pours
Day 12
o Continued forming deck panel closure pours
Day 13 and 14
o Saturday and Sunday – No work
Day 15
o Adjusted deck grades
o Prepare for deck closure pours
Day 16 and 17
o UHPC Closure Pours
Day 18 and 19
o Removing form work and grinding joints
o Fill low spots
Day 20 and 21
o Weekend no bridge work – building approach fills
Day 22
o More grinding and approach fills
Day 23
o Tying barrier steel
o Test run with slip form
Day 24
o Approach work
Day 25
o Slip formed barriers
o Final grading along RR tracks
Day 26 and 27
o More grading work
o Approach rails
Day 28
o Finished approach rails
Day 29
o Opened to Traffic
One day ahead of schedule
(incentive/disincentive deadline)
Now lets see that in
fast motion
Lessons Learned
Project scheduling was intensive
Design details are critical – things need to fit
Allow adequate tolerance on precast elements
UHPC is difficult to grind – reduce exposed area to
minimize grinding
o Have an Engineer on site during construction of
critical elements – be prepared to make decisions
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Questions??
Project Contact:
Jeff Olsen
jolsen@mt.gov
406-444-7610