jreit
Structural
- May 2, 2014
- 95
The contractor has submitted a scaffold design. For the timber joists, he has used the LRFD capacity by multiplying the ASD allowable stress by the LRFD conversion factor of 2.54 for bending and 2.88 for shear a per NDS Table N1 in Appendix N.
He then reduces this LRFD stress by a safety factor of 4 to account for OSHA provisions.
Does the LRFD stress need to be further reduced by 0.85 for bending and 0.75 for shear as per NDS Table N2? I understand OSHA loads should be checked against an ultimate strength but what is an ultimate strength for wood?
The issue comes up again when checking the OSHA 200 lb failure load for timber post and rail.
He then reduces this LRFD stress by a safety factor of 4 to account for OSHA provisions.
Does the LRFD stress need to be further reduced by 0.85 for bending and 0.75 for shear as per NDS Table N2? I understand OSHA loads should be checked against an ultimate strength but what is an ultimate strength for wood?
The issue comes up again when checking the OSHA 200 lb failure load for timber post and rail.
