Since these large holes result in reduced capacity, evaluation of any hole condition beyond that shown in our literature is necessary to ensure structural adequacy. The new round hole capabilities, summarized in the table below, are included in our Javelin®software today and will be available soon in our Forte® single member sizing software. As a result of the testing, proprietary design procedures were developed so that multiple round holes up to 2/3 member depth could be located in Microllam® LVL, Parallam® PSL and TimberStrand® LSL with reduced design capacities and limitations on the number and location of holes. To provide a solution for the changing market needs, we destructively evaluated full scale structural composite lumber beams with round holes of varying sizes to better understand the effects of the holes. With changing energy codes and the desire to run ducts in conditioned spaces such as the floor cavity, larger beam hole capabilities has become a more frequent request from our customers. To take advantage of this key feature, changing direction of ducts, adding soffits and complicated coordination with trades is required to avoid interference with rectangular beams. For example, a maximum 11¼” hole can be cut in a 14″ deep TJI® Joist. In contrast, large holes can be cut into the webs of TJI® Joists. For 1.55E TimberStrand® LSL, a maximum 4 5/8″ diameter hole for members 14″-16″ deep is permitted (see TJ-9000, TJ-9020, TJ-9500, TJ-9505 for additional information). Historically, we have limited hole sizes in Microllam® LVL, Parallam® PSL and 1.3E TimberStrand® LSL to a 2″ diameter round hole for members 7.25″ and deeper. This is because the failure modes and stresses at holes are complicated and not well understood. Installation details can be found throughout TJ-9000 (EAST) TJ-9020 (WEST) - our beams, headers, and columns specifier’s guide.Īs with most things, this document has its limitations.The size and location of holes that can be cut in wood beams, whether sawn lumber, glulam or structural composite lumber, have traditionally been very restrictive with few options for designers outside standardized rules in the building code or manufacturer’s literature. Required information to adequately size a member: Clear Span - the distance between the two inside surfaces of the span supports the distance that is unsupported, or simply, the opening.Bearing - a structural element that supports weight/loads.Dropped Beam - a beam that will be below the members it is supporting.Flush Beam - a beam that will be in the same elevation as the members it is supporting.For exterior/wet applications, see TJ-7102 The wood is placed in a depressurized holding tank that removes the air and replaces it with a preservative. Pressure Treated - wood that has been infused with chemical preservatives to protect the wood from rot.Nomenclature/terminology of this document: Whether you are a designer, builder, or a DIY'er, this document is intended to provide us with the necessary information to size a support member quickly and adequately for you. Sometimes renovations are more challenging like replacing a load-bearing wall or adding an addition to the existing structure. Sometimes this means something simple, like painting, or a little more difficult, like replacing the floors. It is not uncommon for homeowners to renovate their residences.
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