Challenge: Peak was challenged to construct a 1.2M square foot speculative tilt-wall warehouse distribution facility on an inherited site. Along with existing conditions, the site required rock blasting where the rock materials to be used in the retaining wall backfill were deemed nondurable. Additionally, the 1500’ long, up to 50’ high, retaining wall was sequenced to be built before construction of the building pad all with completion scheduled during the winter months.
Solution: Portions of the earthwork were completed prior to Peak’s involvement leaving some unknowns regarding existing conditions when the site was inherited. Soil inconsistencies, discovered through testing, were successfully mitigated with soil cement. Nine weeks of blasting was required to remove rock covering approximately one-fourth of the building pad. Peak was contracted to use the rock for the retaining wall backfill, yet it was deemed nondurable. In order to utilize the rock, the project team adjusted the site grade and imported 100,000 cubic yards of appropriate stone for the backfill. Originally, the project was sequenced to begin at the opposite end of the pad with work moving towards the retaining wall to allow time for the wall to be backfilled while the building foundations began. However, to accommodate a revised schedule, the team re-sequenced to build up one corner of the pad and begin the retaining wall at a lower height, and work counter-clockwise around the building to finish at the highest point of the wall to facilitate the building construction. A portable concrete plant was utilized to pour all the foundations, walls and flatwork concrete. For the large volume needed, concrete was poured four times per week with slab pours targeting 50,000 square feet per pour. Sub-freezing conditions ensued before completing the concrete. Accelerator, hot water and concrete blankets were applied to complete the interior pour-back strips and successfully avoid delays.
