Problem 2) Design a solid one-way slab for flexure using trial-and-error method assuming the following
properties and conditions shown in the figure below.
No. 4 bars for temperature and shrinkage,
spacing=?
No. 4 bars at 10" on-center
Livel load = 100 psf
Dead load = 20 psf + self weight of the slab.
10 ft (simply supported)
fy 60 ksi (Gr. 60 steel)
fe= 4 ksi (Concrete)
1/2/n(a) Estimate the minimum thickness for the slab if deflections are not computed. [Table 4.1 JCM Text]
(b) Design the slab using minimum thickness from part (a) and determine the total factored load per
linear foot (lbs/ft) and also the maximum factored moment (use 150 lbs/ft for the density of the
slab, and design using a 12"-strip).
(c) Determine the minimum cover (cs) for the slab steel if the concrete is not exposed to weather or
ground contact. Then calculate the depth (d) to the primary steel assuming #4 bars will be used.
Hint; d =h-cs-4
(d) Determine the flexural steel required (A) per foot using trial-and-error approach. Let your initial
trial moment arm (d-) equal to 0.9d. Assume reduction factor () equal to 0.9. 'a' converges
after one or two iterations.
(e) Determine the maximum spacing for the slab including the flexural steel requirement from part (d).
S
max
3h
18in
-(12in)
vey
(f) Select 10" as the spacing for the slab (S=10") and calculate the actual steel area provided per foot (
4.) using the following equation:
A₁ = A
12in
S
(g) Check the provided steel ratio against the minimum and maximum steel ratios (Pmin and Pmax).
Calculate the strain (&) in the steel and determine if the reduction factor () is equal to 0.9.
(h) Determine the minimum area for the temperature and shrinkage steel. Select spacing for
temperature and shrinkage reinforcement using No. 4 bars. Remember to check the maximum
spacing requirements,
(i) Calculate the actual design moment capacity, OM.
Fig: 1
Fig: 2