Seismic Retrofitting

Older buildings are not constructed with adequate protection against major seismic events. Buildings that are constructed with Unreinforced Masonry (URMs) are subject to a collapse when exposed to a major event. This threat is not unique to buildings that are constructed with URMs. In general, buildings that are constructed prior to 1950 have minimal provisions to resist lateral loads, and as such, they do not perform well during an earthquake, and/or during high winds. They lack elements such as anchoring of the structure to the foundation, plywood sheathing, and/or metal connectors in critical areas. Additionally, buildings that are constructed after 1950, but before 1990s are also weak in terms of resisting lateral forces. These buildings are equipped with some provisions for lateral protection, but much less than the code requires for today’s buildings. The elements provided in the older buildings (before year 2000) improve the structural performance but are much less than the amount of seismic bracing required for today’s building standards.

Private Eyes Engineers performs a site-specific assessment to identify the current condition of the structures in regard to lateral protection. An “as-is” model of the structural systems is generated from the site-specific assessment that enables the office engineers to analyze and to critique. The “as-is” condition then is compared to what is required for adequate seismic provisions. This process identifies the shortcomings in the lateral bracing system and enables us to prepare a plan for repair.