Design of a one-way slab - Reinforced Concrete with FRP Bars: Mechanics and Design - page 234

The bending moment at the continuous end due to service loads is

M sNeg := M s3 = 5 ⋅ kip ⋅ ft

The value of I e at midspan is

3 3

M
M

−

M
M

crPos crPos

4

I = β⋅ I+1 I=186 in ⋅ e2 g cr2

d2

sPos sPos

The value of I e at the continuous end is

3 3

−

M
M

M
M

crNeg crNeg

4

I = β⋅ I+1 I=83 in ⋅

e3 g cr3

d3

sNeg sNeg

The average value of I e is (as defined in Chapter 4):

I e := 0.85·I e2 + 0.15·I e3 = 170·in. 4

Deflection at midspan: Calculate the moment at midspan due to service
load on a simply supported beam, M o :

2

M = w.1
8

S1

=7.2·ft·kip

o

The maximum deflection under service loads is

2 2

5·M·1
48E ·I

M+M· 1
16E ·I

( )

o1 1

∆ := − =0.221·in .

SL

s1 s3

ce ce

Deflection due to dead loads only is

· w
w

D

∆∆ . := =0.11·in DL SL

S

Deflection due to live loads only is

· w
w

L

∆∆ . := =0.111·in LL SL

S

Multiplier for time-dependent deflections at 5 years (ACI 318-11) is

ξ := 2