Page 19 - Minutes of Proceedings of Civil Engineers Vol CXCV 1913-14 Part 1

frrrrnnrlirrgr,] (' f TIIE WIIITE STAR " DOOK AT SOUTIIAMPToN. 59 ;,lrr.lf'r'rrr shorvn in Fig. 11, Plate 2, immediately behind the quay- ru,rll. lt consists of a reinforced-concrete deck plrrced 10 feet ll rrrclurs belolv quay-level, and resting on the wrlll and on three r','rrx of rcinforced-concrete piles. Theplatformcarlies theload due lrr Llrrr cl,rth and iihe traffic above it, and thus reduces considerably llrl oy111'6n"tring efi'ect of this load upon the pier-and-arch wall in l'r'r,rrt, of it. The pressure on the foundations of the pier:s is tl.rus I'rrrrrglrt within safe limits, and the stability of the whole structure ir rrssrtt'ed. l)uign of Reinforced-Concrete Platfomr.-The combined weight of tlro earth and other load above the platform was estimated at rrlrottt 15 cwt, per square foot. Accordingly, the piles were placed rrlxrtrt 5 feet apart longitudinally and 8 feet apart transversely, the rr,srrlting load on each pile being about 43 tons. The piles were rrtrulo 14 inches square and were reinforced with four steel rods ,,rrch l| inch in diameter. This section was rather more than was trr,r,rled to carry the load, but was adopted in order that the piles nlrortld be amplystrong to support their ownweight when slung,and rrlso to resist the transverse stress due to the lateral pressure of the r,rtlth around them, and thus give relief to the quay-wall. The rruril beams which rested on the piles were formed of rolled steel joists,12 inches by 5 inches by 32 lbs. These were adopted because llrtry lrappened to be available from a disused building pulled down l,u rnrke way for the new works. The joists, not being strong r,trorrgh in themselves for the work they now had to do, were st,r'eugthened by being encased with concrete reinforced with two t-inch diameter steel rods, the whole arrangement forming with the lloor-slabs a series of T beams. The slabs were 8 inches thick and rvcle reinforced with.,oo-inch rods on the lower side, and {-inch rods orr the upper side, spaced 12 inches apart. Ttry Trgnch.-For the construction of the pier-and-arch wall a lnrnporary stage on timber piles was first erected along its river sitle, to carry the cranes and wagons for excavation. Then a row of sheet-piling was driven along the front, and back of the wall- sito for a, certain length. Sheet-piling was also driven at both ends of this length, thus forming a box trench. The whole length of (il-r0 feet was divided up into four such box trenches. Within each Icrrgth of trench the ground was excavated by grab and by hand rlorvn to about 2l feet below quay-level, and timber struts were irrsorted in the usual way, Some of the excavated material was l,lu'own outside the trench on its river side, so as to make up the ground to the same level as on the land side. The rest of the rrrnteri:r,l was taken to sea.