![]() Avoid over-cutting at the corners of the notch. It is important to understand improperly cut field notches may reduce the capacity of a beam and cause serious structural failure. The net section in this area of the beam should be checked for shear and bending stresses to ensure adequate performance.Īll field notches should be accurately cut. When necessary to cut a small notch in the top of an LVL beam (in the compression side) to provide passage for a small-diameter pipe or conduit, the cut should be made in an area of the beam stressed to less than 50 percent of the allowable bending stress. For this reason, the design equations given are shear equations. The notches shown in Figure 6 occur in areas of high shear and lower moment. The notching provisions are limited to uniformly loaded simple-span beams. You May Also Like Seeing the benefits of engineered wood The equations given are empirical in nature and were developed for the conditions shown. For notches on the compression side, a less severe condition exists and equations for the analysis of the effects of these notches are also given in Figure 6 (on page 16). Within the limitation given above, the shear stress at the notch can be calculated in accordance with Figure 6(e). Where LVL beams are notched at the ends for bearing over a support, the notch depth is recommended to not exceed one-tenth of the beam depth (Figure 6, on page 16). If this information is applied to continuous or cantilevered beams, it should be used with extreme caution and only based on rational engineering analyses. All equations and notching guidelines are presented using the same assumptions. LVL beams illustrated in Figure 6 are assumed to be simple span subjected to uniform loads. Rounding the square corner of a notch with a radius of approximately 13 mm is also recommended to reduce stress concentrations in these areas. Stress concentrations due to notches can be reduced by using a gradually tapered notch configuration in lieu of a square-cornered notch. Such notches induce perpendicular-to-grain tensile stresses, which, in conjunction with horizontal shear forces, can cause splitting along the grain, typically starting at the inside corner of the notch. The notching of LVL beams on the tension side results in decreased strength caused by stress concentrations developing around the notch and a reduction of the net cross-section resisting the bending and shear forces. Tension-side notching of LVL beams is not recommended except at end bearings, and then only under specific conditions. Notching of LVL beams should be avoided whenever possible, especially on the tension side of a member. Shear design equations for notched and tapered laminated veneer lumber (LVL). Note, LVL is a proprietary product and the notching and drilling requirements specified by the LVL manufacturer must be followed and supersede the general recommendations provided hereinafter. Therefore, a cautious approach to field modifications is vital. Drilling, tapering, or notching of LVL reduces the net section and may introduce stress concentrations at the notching or drilling location. Most LVL products are used as beams and headers loaded parallel to the gluelines. ![]()
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