Question

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Consider the floor framing plan shown below. This is the second floor of a four-story building The design floor live load is 80 psf. The design roof live load is 20 psf. The structure has a flat roof G4 /2 G2 GS co G3 FLooR FRAMIN LAN I) Assume that the floor between Beams B7 and B8 is supported directly by these two beams only (not by Girders G2 and G3). Beam B7 has a self-weight of 30 plf. The floor slab consists ofa 4-in.-thick, normal-weight, reinforced concrete slab (unit weight - 150 pcf). An additional floor dead load of 15 psf is specified to account for the weight of suspended utilities and fixtures. As an exterior beam, B7 must also support one story of a 4-in.-thick brick wall facade. Assume that the brick wall weighs 10 lbs per inch of wall thickness per square foot of wall surface area. The height of each story is 12.5 ft. Perform the following tasks for Beam B7: a) Compute the tributary area b) Draw a free-body diagram of the beam that includes all the dead loads that act on the beam Repeat Problem 1 assuming the floor is supported on all four sides (B7, B8, G2, G3), and reinforced in both directions For the rest of the problems, assume one-way framing throughout the structure. Perform the following tasks for Girder G5 a) Compute the tributary area b) Compute the influence area c) Draw a free-body diagram of the girder showing only the live loads that act on the 2) 3) girder (use live-load reduction if allowable) 4) Compute the total live load applied to the first story of Column B2. Use live-load reduction where allowed

Assume that the floor between Beams B7 and B8 is supported directly by these two beams only (not by Girders G2 and G3). Beam B7 has a self-weight of 30 plf. The floor slab consists of a 4-in.-thick, normal-weight, reinforced concrete slab (unit weight = 150 pcf). An additional floor dead load of 15 psf is specified to account for the weight of suspended utilities and fixtures. As an exterior beam, B7 must also support one story of a 4-in.-thick brick wall facade. Assume that the brick wall weighs 10 lbs per inch of wall thickness per square foot of wall surface area. The height of each story is 12.5 ft. Perform the following tasks for Beam B7:

a) Compute the tributary area.

b) Draw a free-body diagram of the beam that includes all the dead loads that act on

the beam.

2) Repeat Problem 1 assuming the floor is supported on all four sides (B7, B8, G2, G3),

and reinforced in both directions.

3) For the rest of the problems, assume one-way framing throughout the structure.

Perform the following tasks for Girder G5:
a) Compute the tributary area
b) Compute the influence area
c) Draw a free-body diagram of the girder showing only the live loads that act on the

girder (use live-load reduction if allowable).

4) Compute the total live load applied to the first story of Column B2. Use live-load

reduction where allowed.

Answer 1

Given data: FLOOR FRAMING PLAN Design floor live load = 80 psf Design Roof live load = 20 psf from the Given Design Girder G_5, length of slab panel = 20^1 Breadth of planned = 12^1 L/B = 20/12 < 2 II way outer & according to that tributary area. Tributary area And area = 2x tributary area \r\n But Same it is Said to Consider One way framing Girder takes half load from each Side Therefore ABCD = Tributary area 12 times 20 = 240 sft Therefore influence Area Already we get 2 times tributary Area (because tributary area - 240) 2 times 240 480 sft load taken by Girder is assumed according to the tributary area Therefore Total load = (floor live load + Root live load) times 240 (80 + 20) times 240 100 times 240 24000 Pounds. \r\n Distributing this load Our whole length load = 24000/20^1 1200 Pounds/ft