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

lard war oblalned fmm the aceelerartonr that war pmv~ded fmm the areelemmeter. The
dynam~c equllsbnum m Le vemcal dmeuon tr dexnbed ~n Be follow!ngequatton
where. FlrJ = Impart loading
,on = mar of pro)cctlle
I. = msr of specmen
o, = arceleranon of project~lc.
FIIJ = f m, + 0.5 m.1 o,
The load versus deflcetnon curve can be used for csttmaung the cncrgy rbrorplton
clpxily by ~alculallng the area under the load-deflecuon curve. In add#l!on. load-
dlrplaccment curve cm be apprornmarcd by ~veral straght lhncs wtth dlffcrent slopes
The awend~ng curve has a slope that represents to the ruffncrr of the qeclmen before
cracked. Wtlhxn a glven curve, the pre-craclung stage represented by the rlape of the
rrcendtng curves a normally steeper than the desccndnng curve of the port-cracktng
nrge. As expected. the ~t~ffncss of concrete plater were decreased after cncktng.
Laud-deflccean curves of the test specimens shown ~n Figurer 1.6 lhmugh 4.9
were made wtth dzffeml Erecl resnforeement ratla. md had the rnmc concrete strengths
as well as the same support condtnonr. Rgumr 4.6 to 4.9 show that for pre-cracking
stages. the slope of arcend!ngfurve of the btgpr nnfareemcnc ratto were al~ghtly htgher
thvn thme fmm plates wlrh smaller re8nfommnt rauo. This lnd~cater chat the plate
rttffness tncreased with the ,"crease of nnforeemea mtto.
Repting the lam menrnoned pmcedure for different spec~mens wlth different
concrete strength and suppon eondlttans are shown m Flgures 4.10 thmugh 4.13. All the
figures lndicated that the plate stiffness lnfreacd with the lncrrorr of concrete-strength.