Journal . rmanent set s, and temporary compression c produced per blowby a 2 ton hammer having an effective fall of 50 in. when drivingpiles of 14 in. by 14 in. section are given by the curves of Fig. curves for similar conditions applicable to the drivingof pre-cast concrete piles are given in Figs. 2 and 3. In each of these cases W — weight of the hammer having aneffective fall h of 50 ins. P = the weight of the pile, helmet, and dolly (when fitted).The energy of the blow = The energy of blow available for overcoming the resistanceof the ground = The permanent s
Journal . rmanent set s, and temporary compression c produced per blowby a 2 ton hammer having an effective fall of 50 in. when drivingpiles of 14 in. by 14 in. section are given by the curves of Fig. curves for similar conditions applicable to the drivingof pre-cast concrete piles are given in Figs. 2 and 3. In each of these cases W — weight of the hammer having aneffective fall h of 50 ins. P = the weight of the pile, helmet, and dolly (when fitted).The energy of the blow = The energy of blow available for overcoming the resistanceof the ground = The permanent set s per blow of the hammer at full stroke =v A = Sectional Area of the pile in sq. ins. measured at onequarter its length above shoe; A„ is taken if the shoe isthe larger. THE [MPACT OF [MPERFECTLY ELASTIC BODIES. 137 Curves of efficiency j of hammer blow for 5ofree fall,Driving pitch-pine piles &? Set PER BLOW of a 2ton Ram when DRIVING !!*« lu pitch Pihe piles F,< I. 72 F- P,Le PILE. Resistance to orwihg 221+0A-AREA OF PILE SECTION P- Y/EIQHT OF PILEV/ - OF RAM RATIOS OF ^~ p = pressure in lb. per sq. in. on area A for overcoming theresistance of the ground which should fall within the safestrut value of timber and sheet piles. A* = Resistance to driving in tons = _ *r ? or ^rp- It will be seen that for a given class of pile the value of >? willreach a definite limit corresponding with h and p for each ratiop^z, so that it follows that similar piles driven against a certain pressure p bv a hammer falling h will show the same set per Wblow if the ratio of -j- is the same. pThus for a definite height of fall, p and ==, the set per blow YV measured from the curves for a 2-ton hammer driving a 14in. bv W14in. pile would be identical for other ratios of -j, as for instance a 1^-ton hammer on a 12in. by 12in. pile. 138 THE IMPACT OF IMPERFECTLY ELASTIC BODIES. £ lii z: UJ o DC O u, tj 10 <c o o m UJ nr fi£ o .J K Z D 2 z
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Keywords: ., bookcentury1800, bookdecade186, bookpublisherlondon, bookyear1861
