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

There was aconccnrrarton of stresses at the m a under tmpact load Whde u large
are* of steel had ynelded. the amn at the concrete compresslo" filce lusl reached to n
mrr~mum of 17M) mcm strain at fu~lurc. Thtr Is rppmx~mately half the value tha
obtained expenmentally at the same location under rtvtlc loadfng as repaned prewourly.
Since. I" the case of rmpacr loading. the conciete sudace suddenly perfordled. the
concrew surface have been separated, hence the concrete rtnlnr on the separate face were
no1 recorded.
4.5. Modes of Failure
Moder of fadure of convcnt~onnl two-way plates under rtatle lord cm k clarrllicd lnlo
three casegones
(11 Pure flexural fallure
111 Pure rhear faxlure
(31 Ducuie rhea faxlure.
Pure flexural falure taker place ~n plater where mon of the relnfocemcnt ylclds
before punchlng occurs. Conrequenlly. the plater erhtblt large dcflectlonr pnor the
fanlurr. Usually thlr type of failure happens m the case of lightly remiarced plates. As the
reinforcement ratlo decreases, more steel yxelding approaches la the coral area of the
tsnllan steel relnforcement.
The second category of hlux 1s pure shear fnllure. Pure rhear fanlvrr occurs
when the yl~lding of tk lensson reel Is very lacal~zed at the center of loading. U~ually.
spclmenr with heavy retnforcement ratlo faled under punchtng shear. The thtd t w ol