Anchored Soldier Pile Project Description:
Subsurface Construction constructed a permanent anchored soldier pile for the Williamson Road Parking Garage at Clemson University. Triangle Construction Company selected Subsurface Construction to design and install the ground shoring system.
Anchored Soldier Pile Solutions
The parking deck location required cutting a 40′ to 50′ notch into the existing hillside to create a flat site to construct the deck. The existing ground conditions consisted of uncontrolled fill. While permanent soil nails are often used to build cut walls, we and the design team were concerned that soil nails in the uncontrolled fill would perform poorly long term. This project will receive hardscape surfaces behind the wall. The concern was that post construction movments due to poor wall performance would create a long-term maintenance problem.
Anchored soldier piles were chosen as the retaining wall solution because the anchors are post-tensioned and loaded for the design load. The post-tensioning and locking in load limits retaining wall movements.
Due to concern for collapsing soil and groundwater, the soldier piles were installed with a continuous flight auger, enabling tremming grouting of the drilled holes as in auger cast piles.
Drilling for Soldier Piles – Auger Cast Method
When constructing a permanent pile wall, careful alignment is crucial to a successful project. The piles must be placed with the flange parallel to the wall, at the right location, plumb, and set to the correct depth.
Piles Carefully Placed for Alignment and Verticality
Once the piles are set, lagging begins until the first row of anchors is reached. The anchors are prepped with a grout tube and a regrout tube. The regrout tube is used to create bulbs of grout in the bond zone to increase the anchor capacity in the uncontrolled fill.
Strand Anchors Prepped for Placement
Drilling the First Row of Anchors
Lagging is done carefully and neatly. Studs are welded to the front flange of the piles to receive a permanent cast concrete face.
Close-up of Lagging and the Studs to Attach the Concrete Face
In spite of the effort to do as much work as possible with machines, a lot of handwork is required to prep the flange and weld the studs.
When everything comes together well after careful planning and hard work, you end up with all your ducks in a row.
All Lined Up
Anchors
By Jeffrey W. Coonse, PE |
