codySTR
Structural
- Dec 28, 2017
- 32
NDS2015
Steel-to-wood bolted connection
Background/problem description:
I'm calculating the capacity of a connection for a steel beam framing into the side of a glulam beam. It is a simple connection with an angle bolted to the end of the steel beam using (3) 3/4" diameter bolts and the outstanding angle leg bolted to the glulam beam using (3) 3/4" bolts. The bolt spacing is 3" for both and the bolts are in a single vertical line. The reaction at the connection has a vertical component and horizontal component, thus resulting in a load at an angle to the wood grain. Note: the vertical component results in perpendicular to grain loading on the glulam while the horizontal component results in parallel to grain loading along the member axis on the glulam. I'm calculating Z(perp)' and Z(parallel)' (adjusted design values) and using these to calculate Z_theta' per the Appendix J Hankinson Formula using the angle to grain of the resultant force at the connection.
My question:
In the case of calculating Z_perp', what should the value of "Am" be to calculate "R_EA" to calculate C_G, the group action factor? R_EA is the lesser of (E_s)(A_s)/[(E_m)(A_m)] and (E_m)(A_m)/[(E_s)(A_s)]. Thus, to calculate R_EA I must determine "Am", which is the "gross cross sectional area of main member". Note: NDS 11.3.6.3 states " When a member is loaded perpendicular to grain its equivalent cross sectional area shall be the product of the thickness of the member and the overall width of the fastener group. Where only one row of fasteners is used, the width of the fastener group shall be the minimum parallel to grain spacing of the fasteners". This statement is confusing to me as the bolts are aligned vertically perpendicular to grain of the glulam main member. Should the bolt spacing be used anyway even though the row of bolts is perpendicular to grain???
Steel-to-wood bolted connection
Background/problem description:
I'm calculating the capacity of a connection for a steel beam framing into the side of a glulam beam. It is a simple connection with an angle bolted to the end of the steel beam using (3) 3/4" diameter bolts and the outstanding angle leg bolted to the glulam beam using (3) 3/4" bolts. The bolt spacing is 3" for both and the bolts are in a single vertical line. The reaction at the connection has a vertical component and horizontal component, thus resulting in a load at an angle to the wood grain. Note: the vertical component results in perpendicular to grain loading on the glulam while the horizontal component results in parallel to grain loading along the member axis on the glulam. I'm calculating Z(perp)' and Z(parallel)' (adjusted design values) and using these to calculate Z_theta' per the Appendix J Hankinson Formula using the angle to grain of the resultant force at the connection.
My question:
In the case of calculating Z_perp', what should the value of "Am" be to calculate "R_EA" to calculate C_G, the group action factor? R_EA is the lesser of (E_s)(A_s)/[(E_m)(A_m)] and (E_m)(A_m)/[(E_s)(A_s)]. Thus, to calculate R_EA I must determine "Am", which is the "gross cross sectional area of main member". Note: NDS 11.3.6.3 states " When a member is loaded perpendicular to grain its equivalent cross sectional area shall be the product of the thickness of the member and the overall width of the fastener group. Where only one row of fasteners is used, the width of the fastener group shall be the minimum parallel to grain spacing of the fasteners". This statement is confusing to me as the bolts are aligned vertically perpendicular to grain of the glulam main member. Should the bolt spacing be used anyway even though the row of bolts is perpendicular to grain???