Table of Contents

Structural Configuration Due 6/11

— David Wagner 2007/06/10 19:55

Sketch of project.

Preliminary Sizes

  • All beams are 10” wide by 16” deep: 18×36', 4×120'. [Beam, both ends continuous, minimum h=l/21=26/21=14.86” by Table 9.5(a)]
  • All 18 columns are 10” diameter10”x16”, 20'.
  • All 18 Footings are 3'x3'x1'.
  • The roof slab is 120'x36'x8”. [Solid one-way slab, one end continuous, minimum h=l/24=15/24=7.5” by Table 9.5(a)]

Not considered for this project.

  • The floor slab is 120'x26'x4”.
  • The two walkways are 5'x120'.

Construction Sequence

The construction sequence is standard for reinforced concrete structures.

  1. After grading the site, frame and pour the footings.
  2. Frame and pour the floor slab and floor beams.
  3. Frame and pour the columns, roof beams, and roof slab.

Material Types

  • Grade 60 structural steel.
  • Structural concrete f'c=4,000 psi.
  • Sod roof includes lightweight concrete to taper the roof to slope laterally 2% from the center, sealant, and provision for lateral drainage.

Loading

Dead Loads Bearing Down on Frame

  • Beam Weight: 150 lb/cf x 16/12 x 10/12 = 27 lb/ft
  • Slab Weight: 150 lb/cf x 8/12 = 100 lb/sf
  • Plaster Ceiling Finish: 5 psf
  • Sod Roof: 110 lb/cf x 1' = 110 psf
  • Mechanics: 4 psf

Total wD: 219 psf + 27 lb/beam-ft

Bearing on Floor

  • Exterior Walls: 4” Masonry w/insulation (minus openings): 20'x39 psf =780 lb/ft

Live Loads Bearing Down on Frame

  • Roof: 60 10 psf
  • Rain: 62 pcf x 0.5' = 31 psf
  • Roof A/C unit: 15,000 lb (Considered as a dead point load; the location is unknown at this time).

wL = 10 psf wLr = 31 psf

Bearing on Floor

  • Classroom floor: 40 psf
  • Interior Partitions: 24 psf x 17' = 408 lb/ft
  • Walkways: 60 psf

Live Transverse Wind Load

V=90 mph, I=1.00, K_z(20') = 0.90, K_{zt}=1, K_d = 1

q_z=0.00256 K_z K_{zt} K_d V^2 I = 0.00256*K_z*K_{zt}*K_d*V^2*I = 0.00256*K_z*1*1*90^2 * 1.00 =20.736 K_z

p=qGC_p - q_h(GC_{pi}) = 0.85 q C_p pm (18.9*0.18) = 0.85 q C_p pm 3.4

z (ft) K_z q_z (psf) Windward Wall p (psf)
0-15 0.85 17.6 11.968 ± 3.4
20 0.90 18.7 12.7 ± 3.4
h=21 ft 0.91 q_h=18.9 12.9 ± 3.4

For simplicity, the weighted average over the height of the windward wall is 12.1 ± 3.4

Leeward Wall (L/B=36/120=0.3→C_p=-0.5) p = -8.0 ± 3.4

Windward Roof (h/L=21/36 = 0.6 → C_p=-1) p = -16.1 ± 3.4

Leeward Roof (h/L=21/36 = 0.6 → C_p=-0.5) p = -8.0 ± 3.4

Total wW,max=12.1+3.4-8.0+3.4=10.9 psf

Discussion


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