Civil Engineering Reference
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compression zone due to the concentrated load induced by the shear con-
nector. These large lateral tensile stresses propagate and induce splitting
behind the shear connector and also relieve the triaxial restraint to the bear-
ing zone leading to connector failure through compressive failure of con-
shear connection to less than 20% of its theoretical shear connector strength.
Also, fully anchored transverse reinforcement placed in front of a heavily
loaded single connector did not increase the splitting strength of the slab
nor increase the strength after splitting. However, the transverse reinforce-
ment was found to limit the strength of the split and allow a general gradual
reduction in the shear load after splitting.
Oehlers and Park [
2.51
] found that composite steel-concrete connec-
tions that incorporate a haunch are prone to splitting failure. This is
because the shear connectors have to transfer high concentrations of load
into the concrete slab in the region of the haunch where the side cover to
the connectors is limited. The experimental tests were on stud shear con-
nectors encased in haunches with sloping sides. A similar study, reported
by Johnson [
2.52
], determined the splitting resistance for haunches with
vertical sides and obtained the load-slip curves of the connectors for dif-
ferent haunch slopes. It was concluded that these results can be used to
design composite slabs made with steel decking when the ribs of the steel
decking are parallel to the steel section of composite beam. Push-off tests
on studs in high-strength and normal-strength concrete have been carried
out by Li and Krister [
2.53
]. Eight push-off specimens were divided into
four pairs, according to the concrete strength and the amount of reinforce-
ment in concrete slabs. The authors found that the concrete compressive
strength significantly affects the strength of the shear connections. The
increase in the maximum shear load was about 34% when the cylinder
compressive strength of the concrete increased from 30 to 81 MPa. The
tests showed that the amount of slip at the maximum load was of the same
level for both normal-strength and high-strength concrete. However,
ductile behavior of the studs was observed for the normal-strength spec-
imen after the maximum load. The descending branch of the load-slip
curves for the high-strength concrete was short and steep. The reinforce-
ment in the concrete slabs is a negligible influence on the capacity of
normal-strength concrete (the increase was about 6%) but confined the
concrete surrounding the studs. A negligible effect of reinforcement on
the capacity of the shear connection was observed in high-strength con-
crete specimen.
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