Westbrooke Village Apartments - St. Louis, MO

Wednesday, February 10th, 2016 by Kyle Oswalt

Challenge

New owners of a 250-unit apartment complex planned for a multi-million-dollar renovation, prompting a re-inspection of all buildings on the property by the local municipality. The complex includes multiple, 20-car-capacity parking structures consisting of poured concrete retaining walls which transition to columns that support wood-framed roofs. Four of the parking structures did not pass inspection because their retaining walls were found to be bowing or leaning inward three to eight inches. Many tenants would remain at the complex during renovations; therefore, the owners wished to repair and reopen the parking structures as quickly as possible.

Solution

The owners considered removing and rebuilding the parking structure walls, but ultimately chose a more expedient and cost effective solution to straighten and support the failing walls using GeoLock Wall Anchors. GeoLock Wall Anchors have an allowable tension capacity of 14 kips. The GeoLock Wall Anchor System consists of a steel wall plate, a steel plate anchor buried in the ground, and high-strength all-thread connecting rod. All components and hardware are hot-dip galvanized for corrosion protection.

Each parking structure required thirty (30) wall anchors. Wall plate locations were marked on the inside faces of the walls, and the corresponding locations for the plate anchors were staked. Excavations were made behind the walls to remove the lateral earth pressure so the walls could be straightened. While excavating behind the walls, concrete counterforts were discovered, which had to be saw-cut from the walls and at least partially removed to allow wall straightening. Individual excavations were made at the proposed plate anchor locations approximately 18 feet from the front face of the walls. At each anchor location, a 0.75-inch diameter all-thread rod was driven through a 1.125-inch hole in the wall, through the soil, and into the pre-excavated hole. A plate anchor and wall plate were then connected with the all-thread rod. Anchor spacing varied based on wall and backfill height with a maximum center-to-center spacing of six feet. With all 30 anchors installed per structure, the anchors were systematically tightened and locked in place. Connections were then re-established between the concrete columns and the roof systems. The excavated areas were backfilled, compacted, and seeded.