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Sorbara Shop n Save

Location: Pittsburgh, PA
Owner: Jeff Sorbara
General Contractor: Brayman Construction Corp.
Value: $1.2 Million
Date Complete: May 2012

This project entailed use of a reticulated micropile system to stabilize a four-tiered segmental block retaining wall supporting a 50' high fill, upon which a grocery store was built. From initial construction, the store and wall experienced ongoing and detrimental movement. Brayman was contracted for the remediation after previous attempts, such as a tie rod/dead man system and tiebacks failed to prevent undesirable movements of the structures.

The first step in this project was removing the top retaining wall tier to expose the building footer for micropile installation access. Next, a battered test pile was installed and successfully tested to verify the 105kip axial tension and compression design load capacity. Production micropiles were installed starting from the front of the store and progressing towards the rear. The reticulated micropile system consisted of 83 total piles, battered upslope for tension loads and battered downslope for compression loads. The design for both pile types consisted of 9, 5/8" casing in a 12" diameter hole filled with 4,000psi grout at lengths varying from 58' to 84', including a 20' rock socket.

Following the micropile installation, a 300' long reinforced concrete cap was placed over the micropiles. And was backfilled with onsite material and reseeded. All of the work occurred on a narrow 10' wide bench without disruption to the store’s normal business hours, demonstrating the benefits of micropiles for limited access conditions, minimal noise, and disturbance to adjacent structures.