Minnesota Boardwalk Repair and Replacement

Case Study #55318

1/5 

   

Project Description:

The University of Minnesota Landscape Arboretum. This project required 1200 feet of decaying boardwalk to be replaced and elevated above original position on top of bog to lengthen the life and strength of the lumber. New boardwalk would also be higher to protect from freeze/thaw cycles and widened for better traffic control.

Design Description:

The PierTech® helical piles consisted of:
200 2 7/8” (0.260wt) X 8”, 10”, 12” Helix 3/8”thk 7’ long. Pile design 10 kips compression load.

Construction:

Boardwalk layout called for 12’ board sections, and as little disturbance of bog as possible. 2 piers were installed every 12 feet. Once pier locations were marked, board was fitted for piers and new piers were installed through old boardwalk lumber with articulating 8K5 drive head. Once required psi of 800 was reached, the piles were terminated in load bearing soil, at a variety of depths, from 14’ to 52’, old lumber was torn out and replaced one section at a time. Support beams were then secured to piles with saddle brackets. Bog was not disturbed.