Crow
Creek Bridge – Lake County
Moiese, Montana
The project included a replacement bridge
for a single-span, spill-through abutment bridge over Crow Creek. The
investigation consisted of two borings to a depth of approximately
60-feet. Subsurface conditions were highly variable. Based on
investigative findings, we recommended closed-end, grout-filled pipe
piles driven with a conical end-cap. Submittals included pipe pile
section requirements, a minimum pile length requirement, and allowable
pile capacities. Submittals also included recommendations regarding
streambank slopes, riprap placement, lateral earth pressures, grout
placement and specifications, and approach-fill construction and
material specifications.
McCracken's Bridge Reinforced Soil Slope - FHWA
Wise River, Montana
The project included
pile-supported abutments with reinforced embankment fill. The
embankment slope requirements were 3/4:1 due to lateral distance
constraints. Orion Engineering provided Reinforced Soil Slope (RSS)
geotechnical design using inextensible welded wire. Utilized a
beta version of FHWA design software, in which Orion Engineering
provided development review at FHWA offices in Vancouver, WA.
The software followed FHWA Demonstration Project 82 "Mechanically
Stabilized Earth Walls and Reinforced Soil Slopes Design and
Construction Guidelines", FHWA-SA-96-071, June 1996 . A major
design challenge included the interaction of the RSS design with
vertical piles that were required to support abutment loads. Design
details included wire facing, erosion control provisions,
reinforcement type and spacing, and vertical pile interface with
consideration of construction sequencing.
Deep
Creek Bridge – USFS Region 1
Wilsall,
Montana
The project included a 60-foot span
replacement bridge for a single-span, spill-through abutment bridge.
The investigation was performed using the Orion drill rig. One boring
was performed at each abutment location. Based on hydrologic stream
characteristics, and a thick layer of plastic fine-grained sediments,
we recommended pile support for the abutments. Submittals included a
minimum pile length requirement, and allowable pile capacities for two
different “H” pile sections at various lengths.
