Los Angeles is known for its propensity for seismic activity, from subtle tremors to earthquakes of significant magnitude. Its position on the San Andreas fault line, along the border of the Pacific tectonic plate creates the potential for sudden catastrophic damage to its built environment, or for the slow, subtle undermining of the city’s structures with the shifting of the ground beneath them. In either situation, and the myriad scenarios that exist between the extremes, many of Los Angeles’s existing buildings benefit from seismic retrofits. As it is a common need in the area, it is also a common practice of Los Angeles commercial concrete contractors who seek to improve and bring up to standard the many structures that may be vulnerable to seismic events.
Building code requirements
The buildings in Los Angeles must adhere to the standards of Ordinance 183893 which outline guidelines and requirements to retrofit pre-1978 wood-frame soft-story buildings or non-ductile concrete buildings. The aim of the ordinance is to update existing structures so they can withstand earthquakes of any magnitude and reduce the potential for loss of human life, personal injury, and property damage. The vulnerability of older buildings was made apparent after recent 20th century earthquakes, including the earthquakes that shook Christchurch, New Zealand and demonstrated the inadequacies of their older structures. Los Angeles city officials saw the effects of these natural disasters and required building owners across the city to retrofit concrete buildings with a roof and/or floor supported by a concrete wall or concrete column in order to mitigate the potential for harm.
Retrofitting concrete structures
Concrete, on its own, is less ductile than other building materials. This means that concrete does not fair well with lateral or torsion forces, something a structure would experience in an earthquake. Concrete, however, is a robust and ubiquitous building material that is widely used in construction for its attributes of strength and durability. The ductility of concrete can be improved with reinforcement, such as steel rebar or cables, which allow reinforced concrete slabs to absorb and dissipate the energy of seismic forces. In accordance with Ordinance 183893, non-ductile concrete buildings are required to undergo a retrofit, which can look like that of Los Angeles’ City Hall. The Conco Companies, a local concrete contractor with expertise in commercial retrofits in Los Angeles, worked on this project and provided 30,000 cubic yards of concrete, 3,000 tons of structural steel, and 5,000 tons of reinforcing steel to complete the job.
The Conco Companies’ mission is to be the best supplier of concrete services in the Western U.S. and to bring expertise and incomparable quality to each project. We continue to upgrade and expand our facilities to better serve the growing market for commercial, educational, parking structures, public works projects, and other development. Contact us to learn more about the services from one of the most trusted concrete contractors in Los Angeles.