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If purlins are placed between the joints of a truss top chord, the top chord is considered a beam-column.

An engineer analyzes an unbraced frame and determines the sum of the required load capacities for all the columns in the frame is 245 kips (unfactored) while the total elastic buckling strength of the same frame is 2,783 kips. From these values, what is the ASD amplification factor for sidesway moments of the frame?

An unbraced beam-column within a rigid frame has an Euler buckling strength of 1,641 kips with a story shear of 3.48 kips. What is the drift index for the column?

An engineer analyzes an unbraced frame and determines the sum of the required load capacities for all the columns in the frame is 399 kips (unfactored) while the total elastic buckling strength of the same frame is 3,484 kips. From these values, what is the LRFD amplification factor for sidesway moments of the frame?

Compute the LRFD elastic critical buckling strength, Pe1, for the W10x88 made from ASTM A992 steel with L = 12 ft, P = 520 kip, M = 300 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 using the requirements for the approximate second-order analysis method meaning that a reduced stiffness was used.

A W14x82 of A992 steel is to be investigated for use as a beam-column in an unbraced frame. The length is 13 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 1.10, and the multiplier to account for P-Δ effects was determined to be 1.12. Determine the required second-order axial strength, Pr, of the member.Type of analysisPu (kip)Mtop (kip-ft)Mbottom (kip-ft)Nonsway3404531Sway12030105 

In the equation , the variable α is equal to _____ for LRFD.

A W14x74 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. Bending is around the strong axis. The effective length factors are Kx = 1.0 for the braced case, Kx = 1.0 for the unbraced case, and Ky = 1.0. The multiplier to account for P-δ effects was determined to be 1.05, and the multiplier to account for P-Δ effects was determined to be 1.16. Using LRFD and Cb = 1.0, determine the value of the AISC interaction equation.Type of analysisPu (kips)Mtop (kip-ft)Mbottom (kip-ft)Nonsway3703026Sway552590 

In regard to trusses, purlins placed between the joints of the top chord would switch the top chord from being modeled as an axial-loaded compression member to a beam-column.

The beam-column of A992 steel is part of a braced frame with L = 15 ft, Pu = 300 kip, Mux = 125 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 equationW12x580.956W12x720.700W12x790.634W12x870.571W12x960.513