8/11/2019 Mech vs Lap Splicing
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Mechanical vs. Lap Splin Reinforced Concrete Constructi
For almost 100 years, construction practices in the building
of concrete structures have focused on the use of steel
reinforcement to transfer tension and shear forces. Lap
splicing has become the traditional method of connecting
the steel reinforcing bars, largely due to a misconception
that lap splicing is no-cost splicing.
Lap splicing requires the overlapping of two parallel bars.
The overlap load transfer mechanism takes advantage of
the bond between the steel and the concrete to transfer
the load. The load in one bar is transferred to the
concrete, and then from the concrete to the ongoing
bar. The bond is largely influenced by deformations
(ribs) on the surface of the reinforcing bar.
Continuing research, more demanding designs in concrete
construction, new materials, hybrid concrete/structural
steel designs and other changes in the construction
industry are calling for the use of alternatives to lap
splicing. From the standpoint of function, laps perform
well on bar sizes #6 and #8 of 40KSI yield steel and
3,000 lb. concrete, with a structure of 15 stories
considered
a high-rise. Today, buildings taller than 15 stories are
increasingly common. A high-rise of reinforced concrete
in Kuala Lumpur, Malaysia recently topped over 100
stories, and at least a half dozen other 85-plus story
buildings are under construction or planned.
building occupied by a Feder
the largest renter of office sp
LAP SPLICING PROBLEMS
Over the years, many structu
specifiers have noted that lap
and many disadvantages. ACI
splices are not considered rel
cyclic loading into the elastic
question as to the effectivene
#8, #9, #10 and #11. These ar
in the frame of a reinforced c
question regarding their effic
Over the years, to counter th
lap lengths in the ACI 318 Bu
longer and longer. ACI 12.14.
of lap splices in bar sizes #14
prohibited on bar sizes in ten
12.15.5) and within joints and
yielding (ACI 21.3.2.3).
Fig. 1
Distribution of transverse forces in co
lap le
Study Conducted by:ERICO Concrete Reinforcement Products
