Problem 1: A built-up compression member has the section shown in Figure 1. Use A36 steel for both the channels and plates. The back-to-back distance between two channels is 6 in. The compression member is 25 feet long and pinned at both ends. (a)Calculate the governing effective slenderness ratio to determine if the compressive strength is governed by bucking about the x-x or y-y axis. Does the effective slenderness ratio satisfy the AISC recommended upper limit? (b) Compute the design axial strength, DePn, based on AISCS Section E3. (c) Compute cPn using AISCM Table 4-14 and compare the result to that computed in Part (b). (d) Classify the cover plate, channel web, and channel flange for compactness as either slender or nonslender. Assume Fy = 50 ksi for both the plate and channels. Problem 2: Consider only the in-plane response of the frame shown in Figure 2. Beams and columns are oriented to bend about their strong axis in the plane of the frame. Structural analysis results give the following service loads in column member A: Pp=320 kips, and PL=600 kips, and in column B: PD=200 kips, and PL =360 kips. Use A572 Gr. 65 steel. (a) Can Column A support the loads? [Hint: Beams in the 18-ft bay are pin-supported at beam ends. These simply supported beams should not be included in the G calculations because they are not rigidly connected to the columns.] (b) Can Column B support the loads? Y 1 -PL 1/2X9 12 Column B W14×74 TYP. 2C10X30 W24 x76 . W24 x 76 W24x76 W24 x 76 0 X- - -x 15' Column A W14×90 1 TYP. 1 Y Figure 1 W24×76 W24x76 W24x76 O TÂM 20' 20' 18' 18' TÂM Tân TÂM Figure 2