DESIGN OF REINFORCED CONCRETE SLAB Flexural …DESIGN OF REINFORCED CONCRETE SLAB Flexural...
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DESIGN OF REINFORCED CONCRETE SLAB Flexural Reinforcement (ACI 318-95) *adapted from CSI SAFE(TM) Design Manual Data: Thickness, in 6.0 h Depth of tensile reinf., in 1 d c Effective depth, in 5 d Depth of comp. reinf., in 1 d' Concrete strength, ksi 4.0 f' c Yield strength of steel, ksi 60.0 f y Elasticity modulus of steel, ksi 29000 E s Strength reduction factor, 0.90 φ b Strip width, in 12.0 b Minimun steel reinfocement, f y psi 60000 h b 0.0018 A s;min 2 in 0.1296 A s;min Concrete stress block factors, psi 1000 psi 4000 f' c 0.05 0.85 β 1;calc 0.85 β 1;calc if else if else β 1;calc 0.85 0.85 β 1;calc 0.65 0.65 β 1;calc β 1 0.85 β 1 Neutral axis depth at balanced, d f y psi 87000 psi 87000 c b in 2.959 c b c b β 1 0.75 a max in 1.886 a max Bending moment, in kip 317.952 M u 22 May 2012 17:58:30 - DesignReinforcedConcreteSlabACI318.sm 1 / 2
Transcript of DESIGN OF REINFORCED CONCRETE SLAB Flexural …DESIGN OF REINFORCED CONCRETE SLAB Flexural...
DESIGN OF REINFORCED CONCRETE SLABFlexural Reinforcement (ACI 318-95)
*adapted from CSI SAFE(TM) Design Manual
Data:
Thickness,in6.0h
Depth of tensile reinf.,in1d
c
Effective depth,in5d
Depth of comp. reinf.,in1d'
Concrete strength,ksi4.0f'
c
Yield strength of steel,ksi60.0f
y
Elasticity modulus of steel,ksi29000E
s
Strength reduction factor,0.90φ
b
Strip width,in12.0b
Minimun steel reinfocement,
fy
psi60000hb0.0018A
s;min2
in0.1296As;min
Concrete stress block factors,
psi1000
psi4000f'c
0.050.85β1;calc 0.85β
1;calc
if
elseif
elseβ1;calc
0.85
0.85β1;calc
0.65
0.65β1;calc
β1
0.85β1
Neutral axis depth at balanced,d
fy
psi87000psi87000
cb in2.959c
b
cb
β1
0.75amax
in1.886amax
Bending moment,inkip317.952M
u
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Depth of the compression block,
bφb
f'c
0.85
Mu
22
dda in2.2283a
"CASE(1) a > a_max, Doubly Reinforcemenet"msg
CASE(2) a > a_maxCompressive force developed in concrete alone,
amax
bf'c
0.85C kip76.968C
Moment resisted by concrete compression and tensile steel,
φb2
amax
dCMuc inkip281.018M
uc
Muc
Mu
Mus
inkip36.934Mus
Stress in the compression steel,
β1
amax
d'β1
amax
Es
0.003f's;calc ksi47.8f'
s;calc
if
elsefy
f's;calc
fy
f's;calc
f's
ksi47.8f's
Area of required compression steel,
φb2
amax
dfy
Muc
As1 2
in1.2828As1
Tensile steel for balancing the compression in steel,
φb
d'dfy
Mus
As2 2
in0.171As2
Total area of tensile steel,As2
As1
As
2in1.4538A
s
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