Compute the LRFD moment amplification factor B1 for the W8x58 made from ASTM A992 steel with L = 15 ft, P = 260 kip, M = 200 kip-ft, and Kx = Ky = 1.0. Bending is about the x axis. The member is part of a braced frame, and the given service loads are 40% dead load and 60% live load. The frame analysis was performed consistent with the effective length method, so the flexural rigidity was unreduced.

An engineer analyzes an unbraced frame and determines the sum of the required load capacities for all the columns in the frame is 336 kips (unfactored) while the total elastic buckling strength of the same frame is 2,142 kips. From these values, what is the ASD amplification factor for sidesway moments of the frame?

In unbraced frames subject to sidesway, two amplification factors are needed.

A W14x82 of A992 steel is to be investigated for use as a beam-column in an unbraced frame. The length is 15 feet. First-order analyses of the frame were performed for both the sway and nonsway cases. The factored loads and moments corresponding to one of the load combinations to be investigated are given for this member in the following table. The multiplier to account for P-δ effects was determined to be 1.07, and the multiplier to account for P-Δ effects was determined to be 1.20. Determine the required second-order axial strength, Pr, of the member.Type of analysisPu (kip)Mtop (kip-ft)Mbottom (kip-ft)Nonsway3153522Sway16525105 

Mnt represents the maximum moment assuming that no sidesway occurs.

An unbraced beam-column within a rigid frame has an Euler buckling strength of 1,667 kips with a story shear of 4.99 kips. What is the drift index for the column?

For large axial loads, the bending term of the corresponding AISC interaction equation is slightly _______.

A W14x82 of A992 steel is to be investigated for use as a beam-column in an unbraced frame. The length is 15 feet. First-order analyses of the frame were performed for both the sway and nonsway cases. The factored loads and moments corresponding to one of the load combinations to be investigated are given for this member in the following table. The multiplier to account for P-δ effects was determined to be 1.16, and the multiplier to account for P-Δ effects was determined to be 1.22. Determine the required second-order axial strength, Pr, of the member.Type of analysisPu (kip)Mtop (kip-ft)Mbottom (kip-ft)Nonsway3653533Sway18540110 

The beam-column of A992 steel is part of a braced frame with L = 15 ft, Pu = 350 kip, Mux = 115 kip-ft. A second-order analysis was performed with factored loads and reduced member stiffnesses to obtain the moments and axial force. Bending is about the strong axis. Considering only the following shapes and values obtained from the AISC procedure for LRFD, select the lightest acceptable shape. Let Kx = 1.0, Ky = 1.0, and Cb = 1.0.ShapeValue of AISC interaction equationW12x581.020W12x720.744W12x790.675W12x870.608W12x960.547 

Unbraced frames are frequently referred to as _______ frames.