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

perfomt~an ~ncreascd by about 10-30 percent for rpeelmens under rtrnply supponed end
eondltton. and 50-M) p ent for speclmenr under fixed end condlllon
4.9. Effect of Dynamic Loading on Peak Strain
Carnpanng Le rtatlc loadtng to the dynamic (Impact) loudlng can be rummanzed ~n the
tollaw~ng Eectlan 1" case ot 11311C loildnng, the peak rtmn and the marlmum detlectton
happen an the same tlmc wlth the peak load. However, under dynarnlc laad~ng. the pcsk
slraln accurs rl8ghlly delayed wlth renpfft to !he peak load but ahead lo the rnax~mum
deflectaan. An ~llunrallon of the dnfference behsvtor between normal-strength and hleh-
strength concrete br shown m Ftgurs 4.38.
Under lmpm loadmg. the lenston steel stt-~#tt ts est$matd by about twlce that
under rrattc lordcng. On the other hand. the concrete rtmn on the outer r>& Area of
conraa loading decreased by about half. As dercnbed !n the previous rectlon. the
concrete surface suddenly perfonled under dynmlc lauding. hence the concrete rrranr
on the repanted macould not be recorded.