The type of building is a major factor in respect to which are most at risk for damage from an earthquake
There are several types of buildings including soft-story, tilt-up, steel moment frame, non-ductile concrete and URM (unreinforced masonry). What are their characteristics and what can be determined are vulnerable when faced with enduring an earthquake?
Soft-story structures are common among apartment buildings that are characterized by open parking on the ground floor and dwelling units built above. In other types of buildings (retail, commercial) The soft story ground floor may be enclosed by windows that do not provide any structural support and as a result the structures are considered extremely vulnerable to collapse in a major earthquake.
Tilt-up buildings are a technique of pouring a building’s walls directly at the jobsite and then levitating or “tilting” the panels into position. Many new commercial buildings in California and across the nation utilized this method.
Many tilt-up structures built prior to 1994 were constructed with limited or weak connections that have been proven to fail in an earthquake, causing severe damage and/or collapse. These building defects can be easily corrected with seismic retrofitting.
Steel moment frame structures are characterized by the use of a rigid steel frame of beams connected to columns to support the many floors of the structure. These structures can sustain brittle fracturing of the steel frames at the welded joints between the beams and the columns. If the moment frames reveal cracks and fissures then they may be susceptible to collapse in a major earthquake.
Non-ductile concrete buildings have concrete floors and/or roofs supported by concrete walls, columns and/or frames. Due to their rigid construction and limited capacity to absorb the energy of strong ground-shaking, these structures are at risk of collapse in an earthquake.
URM (unreinforced masonry) buildings are categorized by walls (both load-bearing and not) and other structures made of brick, cinderblock, or other masonry materials are not braced with rebar or another reinforcing material. These buildings are susceptible to earthquake damage when the structural masonry comes apart due to the lack of strength between the masonry.
In order to protect your assets, do your due diligence and know what type of building you are working with and find out how to strengthen your building’s structure when the big one hits.