
27Structural Distress
Code Requirements for Structural Concrete (ACI 318): As with steel or wood structures,
concrete structures are designed with a margin of safety that includes a load factor on the
service load and a strength reduction factor on the nominal strength. For a design example
involving live and dead loading, the design strength must be equal to or greater than the
required strength, or
1.41.7
(2.38)
where
φ is the strength reduction factor
M
n
is the nominal design moment
M
d
is the dead load moment
M
l
is the live load moment
e right side of this equation reects problems where other loading combinations are ...