PROPOSED PROJECT: TWO-STOREY, THREE-UNIT RESIDENCE
LOCATION: YAKAL ST., PHASE 4, MARCELO GREEN VILLAGE, PARAÑAQUE CITY
OWNER: MS. TIA ROSE C. PERFECTO / MR. DON SANTIAGO C. PERFECTO / MR. JUNO C. PERFECTO
DESIGN OF BEAM
CONCRETE BEAM (2B1)
Material Strengths: Shear & Moment Diagram:
fc' = 21 Mpa
fy = 276 Mpa
Constant: *inclusive of wind and/or seismic load
β = 0.85 31.29 KN/m
Φ = 0.9
d = 350 mm 3.50 m
b = 150 mm
Assume 2 layer of steel bars: (d'=90)
d = 350 - 90 54.76
= 260 mm
Compute Pb 54.76
0.85 fc' β 600
Pb =
fy ( 600 - fy ) 22.36
0.85(21)(0.85)(600)
Pb =
(276)(600+276)
Pb = 0.0377
Compute Pmax 25.55 25.55
Pmax = 0.75 Pb
Pmax = 0.75 (0.0377)
Pmax = 0.0282
At the support: At midspan:
Mu = 25.55 KN,m Mu = 22.36 KN,m
Compute ω: Compute ω:
Mu = Φ fc' b d2 ω ( 1 - 0.59 ω) Mu = Φ fc' b d2 ω ( 1 - 0.59 ω)
25.554(1000000) = 0.9(21)(150)(260)(260)ω(1 - 0.59ω) 22.359(1000000) = 0.9(21)(150)(260)(260)ω(1 - 0.59ω)
0.59ω2 - ω = 0.1333 0.59ω2 - ω = 0.1167
0.59 0.59
ω2 - 1.69ω = 0.226 ω2 - 1.69ω = 0.198
Using pythagorean theorem Using pythagorean theorem
ω= 0.321 ω= 0.187
Compute P: Compute P:
ωfc' ωfc'
P= P=
fy fy
0.321 (21) 0.187 (21)
P= P=
276 276
P= 0.0244 < 0.0282 P= 0.0142 < 0.0282
Don't need compression bar Don't need compression bar
Compute area of steel (As): Compute area of steel (As):
As = Pbd As = Pbd
As = 0.0244(150)(260) As = 0.0142(150)(260)
As = 951.60 mm As = 554.90
Compute number of bar (N): Compute number of bar (N):
Try : 16 mm Ø bar Try : 16 mm Ø bar
As As
N= N=
(π/4)(d2) (π/4)(d2)
951.6 554.9
N= N=
(π/4)(16)(16) (π/4)(16)(16)
N= 4.733 N= 2.760
= say 5 bars = say 3 bars
Check for shear:
Vu = R - Wd
Vu = 54.7575 - (31.29)(260/1000) Compute spacing of stirrup:
Vu = 46.6221 KN Av fy d
S=
Vs
/fc' bd 157.08(276)(260)
Vc = S=
6 42190.16
/21 (150)(260) S= 267.17 mm = 270.00
Vc =
6
Vc = 29,786.74 KN d
Smax =
2 use 130 mm
ØVc 260
< Vu Smax =
2 2
0.85(29786.74) Smax = 130 mm = 130.00
< 46.62(1000)
2
12659.36 < 46622.10 KN DETAILS
It need stirrups
150 mm 150 mm
Vu
Vs = - Vc
Ø
46622.1
Vs = - 12659.3645
0.85 350 mm
Vs = 42190.16 KN
Use : 10 mm Ø bar: At support At midspan
2π d2
Av =
4 Tension Bar: 5 16mm dia. Bar 3
2π(10)(10) Comp. Bar: 3 16mm dia. Bar 5
Av =
4
Av = 157.08 mm2