Nevada Stateline Bikeway Boardwalk Case Studies
Situation: The South Demonstration Project is a small part of a larger 30+ mile-long
Nevada Stateline-to-Stateline Bikeway Project along the East Shore of
Lake Tahoe. The project is a result of a joint proposal by local, state
and federal agencies. The intent of the project is to create a shared-use
path that meets American Association of State Highway and Transportation
Officials (AASHTO) and Americans with Disabilities Act (ADA) standards
to serve a broad spectrum of users.
Solution: Through a public competitive bidding process, Ram Jack Nevada / VersaGrade,
Inc. was awarded a subcontract to furnish and install Helical Piles and
Helical Diagonal Braces to provide the foundation for a 250 ft. long x
13 ft. wide, timber-framed and decked boardwalk across an environmentally
sensitive area with a creek and within the limits of a FEMA Flood Zone.
The boardwalk was designed to meet AASHTO H-20 structural loads for occasional
use by Wildland Fire Engines in emergency situations.
Conclusion: Design Loads ranged from 5 kips to 12.5 kips per pile and anchor. While
the Design Loads were provided by the Project Structural Engineer, design
of the helical piles and braces to withstand the design loads was performed
by Ram Jack. Ram Jack’s Engineering Department designed a 2-3/8”
diameter pile with helix configurations to handle the design loads plus
a minimum safety factor of 2. Since the area the boardwalk spans is environmentally
sensitive, the project documents specifically prohibited the use of mechanized
equipment with tracks or tires. Therefore, VersaGrade had to devise a
means to power its Hand-Held 2.5 and 5.0K Torque Drive Heads from a much
greater distance than normal without compromising torque drive performance.
Another challenge was in meeting the tolerances for pile location and
elevation. The 250 ft. long boardwalk has both a horizontal and vertical
curve in it which required a high degree of precision in terms of pile
location and elevation. Other challenges included: Field cutting and drilling
of 296 ea. through-bolt holes for bracket installations where on-site
inspectors monitored our activities to be sure drill cuttings or fluids
did not touch the ground - Daily turbidity readings were taken from the
creek just downstream of our installations. All materials, tools and installation
equipment had to be manually packed into the work area - even the pile
test frame had to be designed and fabricated in sections light enough
to permit manual transport and then assembled in place at each test location.
The helical piling work was completed successfully and ahead of schedule.
Total No. of Helical Piles and Diagonal Braces installed: 148
Pile Testing: Several Piles were tested using both Compression and Tension Tests. Compression
Tests were in general accordance with ASTM D1143. Tension Tests were in
general accordance with ASTM D3689.
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