Tilt-ups have historically done well in seismically active areas. Structural engineer High Brooks, author of "The Tilt-up Design and Construction Manual" says "there's not a single known instance of an in-service failure of the estimated 10 million tilt-up panels constructed to date." This excellent record is due to several factors. First, the large monolithic panels inherent to tilt-ups are strong and often capable of surviving seismic forces. Second, the shape and size of typical panels promotes efficient transfer of shear forces and provides good shear resistance. Finally, large panels have few joints or weak areas that are prone to failure.
The 1971 Sylmar quake in California taught some valuable lessons on tilt-up. One lesson learned the hard way was to directly anchor floor and roof framing to the wall panels independent of the ledger. Anchoring in this way not only helps prevent the walls and diaphragms from pulling away from each other, but also aids in transferring seismic forces from walls perpendicular to the movement of the earth to parallel walls that can better accept the shear forces. Another point to note is that special engineering is required when large open areas are required for door and window openings. This is because the shear force is concentrated on the narrow areas between openings that tend to act as columns rather than wall sections. These columns can be difficult to engineer as shear structures.
