210,000 lbs Helical Piles for 5-Storey Mixed Use Commercial Building

Client: Porchlight Developments
Location: 920 Chancellor Rd, Winnipeg, MB
Capacity: 210 kip [924 kN] ULS, f.
Refusal: End Bearing, Till
Key Hurdles: Access/Mobility/Speed

PROBLEM: VersaPile was engaged during the construction phase to help Porchlight Developments (Porchlight) install piles for a 5-storey mixed use condominium. After driven pre-cast piles had been installed, Porchlight discovered that the roof top HVAC units specified were unavailable. The replacement units were so different that structural implications were inevitable. Some of the pre-cast piles already installed were not going to work for the revised structural design. It was deemed infeasible to mobilize driven pile rigs. Moreover, the work site was very tight, many of the structural concrete walls for the parkade were already in place. The options were caisson piles or helical piles. Helical piles were chosen due to quick mobilization, the ability to build on the piles immediately and reduced costs.

SOLUTION: Porchlight contacted their geotechnical engineer to determine what their options were for resolving the new point loads that resulted from their HVAC unit re-specification. Silvestre Urbano had experience working with VersaPile, a helical pile contractor, on numerous projects and knew immediately that helical piles offered the right solution for this dilemma.

Helical piles not only offered a less complex mobilization strategy, they offered a better technical solution. Adding new driven piles would create a few problems; unwanted vibrations on a developed worksite, mobilization issues and high cost per pile.

Concrete walls had already been formed and cast for the parkade walls. It was deemed undesirable to subject the walls, that were not yet laterally braced by the floor system, to the vibrations that resulted from driving pre-cast concrete piles.

Mobilization was a problem for pre-cast piles as well, due mostly to the length of pile required to encounter glacial till (55' or 16.7m). This would have entailed staging in a neighboring parking lot with the pile rig moving in and out of the site for each pile. Additionally, there was not enough space for a support crane and a drilling rig required for pre-boring to reduce vibrations.. During construction the site had become rough and uneven, posing further problems for driven rigs.

Helical piles carried none of these disadvantages and offered a few

advantages such as piles customized to the exact load required, quick turnaround times (roughly 2 weeks for custom piles) and very concise mobilization and installation.

From the time that Porchlight reached out to VersaPile, to the last pile going in the ground was a little under a month (including a week off at Christmas). The longest portion of the scope of work was simply the manufacture and shipping of custom high capacity helical piles from VersaPile's supplier in Western Canada to Winnipeg.

VersaPile mobilized with their John Deere 290G 30ton excavator, a New Holland C245 and a RAM 3500 with a gooseneck trailer hauling the piles.

The piles consisted of a 30' lead and 25' extensions and were installed with the 290G coupled with a high-capacity Eskridge D1400 115 kip-ft torque drive. The piles were all installed to refusal by torque in dense glacial till to meet the specification and supervision of the geotechnical engineer.

The installation itself took roughly 3 days with an additional day required for a CWB certified welder to install the steel pile caps. The piles were turned over to Porchlight with installation record and a sealed letter of inspection from the Pile Engineer (retained by VersaPile).

CONCLUSION: VeraPile was able to help Porchlight Developments find a cost-effective solution for their mid-construction issue in a timely manner. Seven high-capacity helical piles were installed in a partially constructed 5-storey mixed use condominium to meet loads up to 210 kip [920 kN]. Porchlight was very impressed with the professionalism and workmanship from design through to installation.

CASE HIGHLIGHTS:

7 PILES FOR 5-STOREY MIXED USE BUILDING

• Qty: 3 - 8-5/8" dia., 55' long shaft, 30" dia. helical
  • 185 kip [814 kN] ULS, req. torque: 115 kip-ft [155 kN-m]
• Qty: 3 - 8-5/8" dia., 55' long shaft, 32" dia. helical
  • 200 kip [880 kN] ULS, req. torque: 115 kip-ft [155 kN-m]
• Qty: 1 - 8-5/8" dia. ., 55' long shaft, 35" dia. helical
  • 210 kip [924 kN] ULS, req. torque: 115 kip-ft [155 kN-m]

Installed with:

• Primary: JD 290G 30T Excavator w/ Eskridge D1400 Drive
• Support: New Holland C245

 

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