TABLE OF CONTENTS Example 6.19 will be reevaluated assuming that the ends of a deeper section are notched at the supports to provide the same member depth over the support. In Example 6.19, the adequacy of a 6 14 rough-sawn beam was determined for the given loads. In this example, a notched 6 18 rough-sawn member is used as the beam in Fig. 6.19a. Since the notches are at the supports only, they will only impact the shear calculations.
EXAMPLE 6.20 Notched Beam
Determine if a 6 18 rough-sawn beam with notched supports is adequate, considering shear only, to support the given loads. The notches are 4-in. deep and sufficiently long to provide adequate bearing length at the support. The notch does not extend past the face of the support. See Fig. 6.20. The depth of the notch allows the remaining depth of the member to be compatible with the 6 14 beams supported on the same level.
Notch Size
NDS Sec. 4.4.3 limits the size of notches at the ends of members for bearing over a support. The depth of such notches cannot exceed one-fourth of the total depth d of the beam. In this example, d = 17 5/8 in. The maximum notch depth is 4 13/32 in., which is greater than the 4-in. notch specified in Fig. 6.20. The notch is permissible by the NDS.
Shear Check
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