Multi Family End Bearing Piles Near Red River in West St Paul, MB

Client: Forthright Properties
Location: 3813 Main St, West St. Paul, MB
Capacity: 5 kip [22 kN] to 43 kip [191 kN] ULS, f.
Refusal: End Bearing, Till
Key Hurdles: Budget / Saturated & Sloughing Soils / Timeline / Winter Build / Disruption to Tenants in Nearby Buildings

PROBLEM: VersaPile was engaged prior to construction by Forthright Properties which had received a geotechnical report indicating that eight (8) multi-family structures they were building at a new development site would require end bearing piles. Due to proximity of the site to the Red River, the soils were sloughing, saturated and generally low capacity, as a result the piles would need to bear in dense till. The construction was happening in the winter months and timeline was important. Another consideration was that Phase 1 of the development had already been built and the units were rented making loud and high vibration piling solutions less desirable. Finally the budget had to be right as it does in most any development project.

SOLUTION: Building a condominium from scratch requires a detailed approach. Designing and building a condominium to occupy a heritage building shell from an iconic 1920's theatre is especially challenging. Only the most subtle of changes were permitted be made to the exterior of this landmark building. Even large holes in the roof were off limits.

VersaPile worked with Beach Rocke (Structural) from Winnipeg, MB and DGH Engineering (Pile Engineer) from St. Andrews, MB to come up with efficient pile layouts for the eight structures. John Rocke P.Eng. worked diligently to ensure an efficient pile layout for each structure working the limits of the 4-1/2" helical piles chosen for their overall value for price. The piles designed to be robust enough to handle the frozen soils, as the bulk of the work was in the winter, they would also need to penetrate into the dense till. Pile caps were engineered to be welded to each pile and provide an effective and convenient transition to Insulated Concrete Form (ICF) foundation walls on which the structures were built.

The depth to firm till varied between 36' and 51' from grade. From excavated depth, the piles reached a total of up to 43 feet of embedment, installed in two sections through the low capacity, saturated and sloughing clay and end bearing into dense till.

Forthright Properties is a legacy builder which thinks long term in every project they endeavor, for this reason the piles were hot-dip galvanized. The investment in hot-dip galvanization effectively increased the life expectancy of each pile by 2 to 2.5 times, ensuring solid foundations for generations to come.

To help with timely installations, some of the buildings were piled using two CAT 210 installation rigs outfitted with Pengo RT20 and RT40 anchor drives. The rigs provided sufficient crowd for the piles to penetrate and proceed through the first few feet of frozen Manitoba clay as well as to penetrate the soft till layer encountered prior to embedding in dense till. The reach of the installation rigs allowed for efficient installation of each pile in just two sections.

Other sites were piled during the spring and summer months and, although frozen soils were not an challenge, the installation rigs were still large enough to install helical piles in two sections and to drive through soft till layers achieving a solid end bearing installation.

For added efficiency of loading piles a Kubota U35 midi-excavator was on-site with pole grapple. The combination of installation rig with pole setting support equipment allowed the friendly and professional VersaPile crew to install more than 1,500 lineal feet of helical piles per day.

The versatile equipment chosen for each building meant affordable mobilization. This was important since the buildings were often piled months apart. Had alternative piling solutions such as a driven precast or driven timber piles been selected, the mobilizations would have been much more costly and rigs may have sat on-site for weeks, making it difficult for the various trades to navigate the very busy project site.

There were no complaints to the knowledge of VersaPile from other trades on-site or tenants of the nearby Phase 1 development with regards to noise or vibrations. Alternative end bearing pile solutions are pounded in the ground which results in vibrations as well as very loud installations which can be heard from more than a kilometer away. Helical pile installation by contrast is no louder than the sound of an mid-idle excavator running.

CONCLUSION: VersaPile, with a team of project engineers, piled eight multi-family buildings which were built solid in less than solid ground and in record time. The customer may have preferred the budget of a cast-in-place concrete friction pile however the soils had different plans - the result however was a budget friendly alternative vs the default precast driven pile solution. The helical pile installation process was efficient and did bother the nearby tenants or other trades working on the busy site.

CASE HIGHLIGHTS:

615 - MULTI-FAMILY BUILDINGS

• 43,000 lb [191 kN]
• 4-1/2" Ø shaft, 16" single helix
• 32-43' depth to refusal
• 22.5 kip-ft [30.5 kN-m] torque

Installed with:

• CAT210 (20T Excavator)
• SK170 (17T Excavator)
• Pengo RT40 / Pengo RT-20
• Support with U35 (3.5T Excavator) & Pole Grapple

80 - DECK PILES

• 5,000 lb (22 kN)
• 2-3/8" Ø shaft, single 12" helix
• 10'-15' depth to min. torque
• 3 kip-ft (4.1 kN-m) torque

Installed with:

• Kubota U-17 (1.7T Excavator)
• Pengo RS-7 Drive

 

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