Large panels, numerous window openings, and a small building footprint were some of the problems faced by Lusk Construction Company when they built the 25 million dollar Barranca Court Office Buildings in Irvine, California. Barranca Court consists of two mirror-image three-story office buildings with underground parking. Dimensions of two of the tilt-up panels were 56 feet, 5 inches high and 40 feet, 5 inches wide. The bottom of each of these panels, to a height of 12 feet, was 12 inches thick and included a 34-foot-wide opening. These asymmetrical tilt-up panels are among the largest ever to be erected in Southern California.
Engineers for the panel supplier built hardboard models of each panel at a scale of 1 inch to 1 foot. These models enabled the design team to calculate and verify the location of the center of mass for each panel configuration. The engineers also built a representative model of the crawler crane by using a series of pulleys and horizontal spreader bars. With all variables combined, the model's rigging arrangements indicated whether or not the equipment could safely hoist the huge panels. Another problem was the back-to-back location of the building pads, which made crane access to the foundations difficult. To solve the problem, temporary casting slabs were poured parallel to each other and on opposite sides of the building footprint.