DESIGN OF REINFORCED CONCRETE BEAM Flashcards
A mixture of water, cement sand and gravel, crushed rock, or other
aggregates.
CONCRETE
As a structural member, concrete can be made to carry tensile stresses
(as beam in flexure). It is necessary to provide steel bars to provide the
Tensile strength lacking in concrete
REINFORCED CONCRETE
used in concrete may be fine (usually sand) which
Pass through a no. 4 sieve (about 6 mm in size). Materials retained are
coarse aggregates
AGGREGATES
shall be clean and free from injurious
amounts of oils, acids, alkalis, salts, organic materials, or other
substances that ,may deleterious to concrete or reinforcement.
WAter
According to NSCP (Section 408.6), modulus of elasticity πΈπ
for concrete for values of π€π
between 1500 and 2500 kg/π3
According to NSCP (Section 408.6), modulus of elasticity πΈπ
for concrete for values of π€π between 1500 and 2500 kg/π3may
Be taken as
πΈπ = π€π^1.5 0.043 β πβ²π (ππ πππ)
π = π€π^1.5 0.043 β πβ²π (ππ πππ)
where;
fβc = 28-day compressive strength of concrete in MPa,
π€π = unit weight on concrete in kg/π3
for normal concrete
πΈπ = 4700 βπβ²π
for no prestressed reinforcement
πΈπ = 200,000 ππa
Diameter of bend measured on the inside of the bar, other than for stirrups and ties in
sizes ___________
10 mm through 15 mm
Inside diameter of bend for stirrups and ties shall not be less than_____________ . For bars larger than 16 mm, diameter of bend shall be in accordance with
Table 1.1
4ππ for 16 mm bar and
smaller
According to Section 407.7, the minimum clear
spacing between parallel bars in a layer
Shall be
ππ but not less than 25 mm.
Where parallel reinforcement is aced in two or
more layers, bars in the upper layers should be placed
Directly above bars in the bottom layer with clear distance
Between layers not less than
25mm
When spirally reinforcement or tied compression members,
clear distance between longitudinal bars shall be not less
than
1.5 ππ nor 40 mm.
Groups of parallel reinforcing bars bundled in contact to act as unit shall be limited o
four in any one bundle.
BUNDLED BARS
Bundled bars shall be enclosed within stirrups or ties and bars larger than ____ shall
Not be bundled in beams.
32 mm
shall be treated as a single bar of a diameter derived frm the equivalent
total area
BUNDLED BARS
The individuals bars within a bundle terminated within the span of flexural members
should terminate at different points at least ____stagger.
40ππ
Required strength U to resist dead load (D) and love load (L) shall be at least equal to
U = 1.4 D + 1.7 L
If resistance to structural effects specified wind load W are included in design, the following combination
of D, L, and W shall be investigated to determine the greatest required strength U.
U = 0.75(1.4D + 1.7 L+1.7W)
Where load combinations shall include both full value and zero value of L to determine the more severe
condition, and
U = 0.9D + 1.3 W
If resistance to specified earthquake loads or forces E are included in design , the following combinations of
D, L and E shall be investigated to determine the greatest required strength U:
U = 1.1D + 1.3L + 1.1E
Where load combinations shall include both full value and zero value of L to determine the more severe
Condition, and
U = 0.9D + 1.1 E
But for any combination of D, L and E, required strength U shall be less than Eq. 1-2
If resistance to earth pressure H is included I the design, required strength U shall be at least equal to:
U = 1.4D + 1.7L + 1.7H
