Shoring existing structures can be a tricky business and the older the building, the trickier it can become. Many older structures do not have drawings of the existing construction and if they do, they are not always reliable. Many buildings go through generations of remodel with additions, renovations and improvisations that are not always documented properly. Without proper documentation, it is sometimes difficult to determine the load bearing members in an existing building and this makes it difficult to shore. If you can’t figure out where the loads are concentrated, you can’t figure out how to safely and economically support anything.
When undertaking the task of existing structure shoring you should consider consulting an engineer – and I don’t just say that because I happen to be an engineer! The peace of mind that you get from entrusting this work to an engineer far outweighs the risk of liability if something goes wrong during the shoring operation.
Things that your engineer will need to know before starting a shoring plan include the type of work being performed, the boundaries of work, distance to any excavation, dimensions of the building and location of load bearing members. Other pertinent information includes the dead load of the supported area and any anticipated live loads – for example, will an office building remain occupied or is your customer trying to keep the parking garage operational during construction? Depending on the scope of the job, snow and wind loads may also need to be taken into account. Be certain to consider any special circumstances like required access openings in the shoring plan and work sequencing that would affect the standing shores. Drawings, schematics and photographs can be provided to convey most of this information but, in some cases, it is easier and most cost effective for the person designing the shoring plan to visit the site.
If an existing structure is improperly shored, there is danger of damaging the building or of a collapse. Providing as much accurate information as possible to your shoring designer will help to minimize risk and ensure the most accurate and economical design. Don’t take chances, if in doubt get a professional engineer involved and maximize your chances of shoring success!