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The beam-column of A992 steel is part of a braced frame with L = 15 ft, Pu = 300 kip, Mux = 120 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 equationW12x580.941W12x720.688W12x790.624W12x870.561W12x960.505 

Compute the LRFD moment amplification factor B1 for the W12x106 made from ASTM A992 steel with L = 13 ft, P = 220 kip, M = 220 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 14 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 1.14, and the multiplier to account for P-Δ effects was determined to be 1.14. Determine the required second-order flexural strength, Mr, at the top of the member.Type of analysisPu (kips)Mtop (kip-ft)Mbottom (kip-ft)Nonsway4804532Sway19035105 

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 1.20, 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)Nonsway3103033Sway1555580 

An engineer analyzes an unbraced frame and determines the sum of the required load capacities for all the columns in the frame is 255 kips (unfactored) while the total elastic buckling strength of the same frame is 4,847 kips. From these values, what is the LRFD amplification factor for sidesway moments of the frame?

An example of beam-columns can sometimes be found in roof trusses when purlins are placed at the joints.

An unbraced beam-column with no moment frames has an Euler buckling strength of 1,771 kips with a story shear of 4.78 kips. What is the drift index for the column?

Many isolated one-story columns can be realistically treated as _______.

An engineer analyzes an unbraced frame and determines the sum of the required load capacities for all the columns in the frame is 439 kips (unfactored) while the total elastic buckling strength of the same frame is 3,525 kips. From these values, what is the ASD amplification factor for sidesway moments of the frame?

Most beams and columns are subjected to some degree of both bending and axial load.