Understanding Building Types & Structural Failures (Video)
Sometimes a simple video is worth a million words. For a complete understanding of a sometimes-over-complicated explanation of building basics and how structural failures occur, please view the following video:
The video provides a simple explanation of how structural failures occur. However, many different types of buildings exist, including concrete tilt-up, URM (unreinforced masonry), non-ductile, steel frame, and soft-story. Below, we outline each type and its vulnerabilities relating to seismic activity.
Concrete tilt-up buildings have limited or weak connections from the roof to walls and continuity ties. Because of the heavy concrete walls, in the event of an earthquake, these walls want to pull apart from the roof, creating a collapse hazard. Evidence from previous earthquakes suggests that these buildings can be quite dangerous during a seismic event and suffer extensive damage.
A URM (Un-Reinforced Masonry building) is a type of building where load-bearing walls, non-load-bearing walls, or other structures are made of brick, cinderblock, tiles, or other masonry material that is not braced by reinforcing materials (rebar). Unreinforced masonry walls lack steel reinforcing bars, which add a lot of strength to the structure of a building.
Non-ductile concrete describes the basic characteristics of these types of buildings. They are very strong but brittle. “Non-ductile” means inflexible, so non-ductile concrete buildings are likelier to crumble or collapse in an earthquake, posing greater financial and life-safety risks.
A steel frame is a building design usually with a “skeleton frame” of vertical steel columns and horizontal I-beams, constructed in a rectangular grid to support the floors, roof, and walls, which are all attached to the frame. Structural steel framing is a durable, reliable, and sustainable option for low-rise to high-rise building projects.
A soft-story is a multi-story structure with a first floor that is open and much less rigid (soft) than the floors above. Many examples of buildings with soft-story conditions include multi-family apartment buildings with tuck-under or subterranean parking and retail centers with open storefronts and minimal reinforcement on at least one elevation.
If you’re interested in learning more about strengthening your structural real estate assets, we offer educational presentations on types of buildings, seismic retrofits, roof condensation, and structural repairs.
Contact Saunders Seismic today. We are the seismic solution specialists and can assist you with every step of the seismic retrofit process.