Civil Engineering Reference
In-Depth Information
16.13
OPENINGS IN SLAB SYSTEMS
According to the Code (13.4), openings can be used in slab systems if adequate strength is
provided and if all serviceability conditions of the ACI, including deflections, are met.
1.
If openings are located in the area common to intersecting middle strips, it will be
necessary to provide the same total amount of reinforcing in the slab that would
have been there without the opening.
2.
For openings in intersecting column strips, the width of the openings may not be
more than one-eighth the width of the column strip in either span. An amount of
reinforcing equal to that interrupted by the opening must be placed on the sides of
the opening.
3.
Openings in an area common to one column strip and one middle strip may not in-
terrupt more than one-fourth of the reinforcing in either strip. An amount of rein-
forcing equal to that interrupted shall be placed around the sides of the opening.
4.
The shear requirements of Section 11.12.5 of the Code must be met.
PROBLEMS
16.1
Using the ACI Code, determine the minimum thick-
ness required for panels
and
of the flat plate floor
shown in the accompanying illustration. Edge beams are
not used along the exterior floor edges.
16.2
Assume that the floor system of Problem 16.1 is to
support a service live load of 80 psf and a service dead
load of 60 psf in addition to its own weight. If the
columns are 10 ft long, determine depth required for an
interior flat plate for panel
.
16.3
Repeat Problem 16.2 for panel
in the structure of
Problem 16.1. Include depth required for one-way and
two-way shear. (
Ans.
Use 10 in. slab.)
c
f
3000 psi and
f
y
60,000 psi. (
Ans.
9.07
and 8.12
)
