Elevator Pit Foundation Modification

Description

NCJC Elevator Pit | Columbus, Ohio

How do you modify an elevator-pit foundation when the walls above it already carry the loads of a nearly completed building?

At the NCJC project in Columbus, Ohio, crews needed to install a thicker reinforced concrete mat slab beneath two elevator pits serving a 5-floor building. The work required removing the existing pit slab and excavating below the footing while maintaining support for the elevator-core walls.

Temporary Support During Construction

Twenty-two MAGNUM® MP325 Push Piers with MP1006 Reverse Angle Brackets provided temporary underpinning for the existing footings. The piers reached an installation depth of 40 feet, with a reported installation load of 39 kips and hydraulic pressure of 4,700 psi.

Pier placement required coordination around existing sump pits and rammed aggregate piers installed as part of the original foundation system. The push-pier layout accommodated these features while providing support within the elevator pits.

Making Room for the New Mat Slab

With temporary support in place, crews removed the existing slab while retaining the concrete needed beneath the brackets. MAGGEO’s construction sequence limited excavation to a maximum of one foot below the existing footing before installation of the new reinforced mat slab.

The new concrete extended beneath the existing footing, allowing crews to complete the foundation modification while the push piers maintained temporary support during the work and curing period.

Successful Completion

The elevator-pit foundation modification was completed successfully. The project demonstrates how MAGNUM Push Piers can provide temporary underpinning during foundation alterations, with product selection, installation layout, and construction sequencing coordinated around existing site conditions.