a[mm]/l - Memorial University of Newfoundland DAI

It war not parrtble to determnnc a relmahle value far the shear-cmhng load. 1.e.
the load dl whmch the shear cracks rtmcd up The erumntlon of such load from the crack
pattern was uncenan because there was no fundamental d~fferencc between shes crack
and flexural crack erpnnd~ng m tangentgal d#rectsan However. employng the decrease of
!he rlcel stram ~n the nnforcement can be used as a p de for delermlnsng Lhe shear
crarkln: load? As pmpred hy K~nnunen and Nylander (10601. the observed punching
lards of two-way concrete slabs w~rhout shear re~nforcement were wound 70-80 percent
of r k ult!mnte lo&.
For dynamtc loadmg. a rbght trend of mon tenston face damilge and more
concrete stnpplng aceumd at u larger relnforccmenl steel ntlo p than the rmallcr ratlo.
The same obssrviltlan war more evident for the care of hsgh-strength concrete th~n
normal-strength eoncrele Radtal cncb expandtng to the edger of the spclmenr were
evdent on all the test spclmenr. The cnck lnd~eater that bendmg and shew fatlure
mechrnl~mr were detected m all the specnmm Therefore. ~t can be concluded tha all the
rpeclmenr were falied under aduclnle shctr failure
4.2. Load-Deflection Characteristics
The Impact lauds vmur the deflccuon at the center of the plater for the dlfferea rest
wner an pnscntcd in Ftgure 4 6 through 4.11. The load-time curves for the different lest
sene3 have also shown in Figure 4.14 thmugh 4.17. whtle the dcfleet~an -tmc curves
given m Figure4.18 thmugh 4.21.
The deflsctnonr far all tested specimens were obtained using LPDT measurements
at the center of rpmmen. Urlng dynamne tquillbnum m the venrcal dlmdon, the Impact