Understanding the Role of Structural Inspectors in Seismic Retrofits
Structural inspectors for seismic retrofit are not exactly the same as structural engineers and are sometimes confused, although they share certain common tasks. While some contractors want structural inspectors to have engineering backgrounds, many inspectors get their training on the job. The state where the inspection takes place defines the qualifications for structural inspectors.
Checking the Foundation and Floors
The main role of a structural inspector is to look for cracks and other problems with a building’s foundation, floor, walls, ceiling, and roof. The inspector aims to identify structural issues associated with aging or poor installation. The inspector’s job is to be objective and assess the property’s health from its foundation to the roof to determine if retrofit work is needed.
The inspection begins by studying the foundation, checking how the structure connects with it, and checking whether or not it’s securely bolted down. It’s imperative that the building be built on a solid foundation to avoid movement, which can lead to cracks throughout the structure.
When the ground floor is not level, it indicates vertical movement. Soft soil can also cause movement. A building with pillars or concrete steps that have experienced vertical movement may show cracks in the respective structures. Separation cracking is a type of cracking that reveals which direction the structure is moving. When the central part of a building begins pulling away, it’s a sign that retrofit is necessary.
Looking for Cracks Throughout the Building
Structural inspectors look for cracks throughout the building, particularly around doors and windows, which are the weakest points in a foundation. Vertical cracking in the drywall or when the baseboard becomes detached from the wall also indicates movement in the foundation. Meanwhile, a sagging roof indicates structural movement.
Determining Retrofit Work
The inspector takes notes that will become part of a detailed report for the building owner. After analyzing the entire building, the contractor determines what type of retrofit work is needed to make the building safer for occupants.
Several retrofit strategies based on the building’s existing structure are used to strengthen it to withstand seismic activity. Concrete tilt-up and reinforced masonry (CMU) are buildings that may need roof-to-wall anchors and continuity ties so that the roof does not fall apart during a strong earthquake. Un-reinforced Masonry (URM) is a type of building that needs roof-to-wall connectors, continuity ties, and a new plywood overlay for the roofing.
Soft-story buildings typically have an open first floor, consisting of a garage with apartment or office units on top. These buildings can be extremely vulnerable during a quake. Sometimes, steel framing or concrete footing is needed to strengthen these structures.
Secure Your Building with Expert Seismic Retrofitting
Retrofit specifications begin to take shape following a thorough structural inspection. Contact Saunders Seismic to learn more about making your building safer so that your tenants feel more at ease and are protected from natural disasters.