There are a wide range of options for strengthening existing residential buildings, depending on the era, condition and the exiting design of the building. These remedial actions usually involve strengthening connections between structural elements, increasing the structure’s capacity to resist seismic loads and strengthening connections between non-structural elements and the frame. Strengthening is not likely to be required if the house was built after 1980.
Like residential buildings, strengthening of commercial and public buildings is primarily concerned with improving the connections between structural elements, increasing the structure’s capacity to resist seismic loads and improving the connections between non-structural elements and the main structure.
Unlike residential buildings, where seismic strengthening improvements to existing buildings are voluntary, commercial and public buildings can pose a significantly greater risk to the public during an earthquake. Therefore, all buildings, not just new builds, are required to comply with a minimum level of seismic performance.