564 PROCEEDINGS OF SECTION J. 



The following papers were read : — 



1.— RECENT PROGRESS IN SINKING DEEP FOUNDA- 

 TIONS FOR ENGINEERING WORKS. 



By Charles Ormsby Burgb, M. Inst., C.E. 



\_Abstract.'\ 



After a short Introduction, the paper refers to the extension of 

 railways and the consequent necessity of bridging large rivers, as 

 the chief cause of progress in deep foundations, and to the im- 

 provement in Portland and other cements as rendering chiefly 

 such progress possible. 



In earlier times timber piling was used exclusively for deep 

 foundations, except in India, where a difi'erent method, to be 

 adverted to presently, was pursued. The almost general substitu- 

 tion of iron for timber in engineering works led to the introduction 

 of the screw-pile first used by Mitchell in 18.34, since largely 

 employed in bridging rivers and in marine piers, there being two 

 forms, namely, hollow tubes of cast iron and solid forgings of 

 wrought iron. These piles are, however, unsuitable for very deep 

 foundations where the overlying material is soft or liable to scour, 

 as it is impossible to brace the piles below ground, and the whole 

 structure may therefore become unsteady. Instances of large 

 bridges of this type, with which the author had been connected, 

 are given, in which cylindrical piers had to be subsequently sub- 

 stituted for piles. Many marine piers have been constructed 

 successfully on screw piles, as they are not subject to heavy and 

 fast traffic. One at Huelva, in the South of Spain, is specially 

 mentioned as embodying a novel principle of obtaining increased 

 bearing surface, the area of the screw blades being considered 

 insufficient. Large platforms were sunk round each group of 

 piles, as far as they would go, when temporarily loaded with 

 weights largely exceeding the permanent maximum load on the 

 group. They were then strongly connected with the piling, and 

 the temporary loading removed ; the pier, therefoi-e, chiefly rests 

 on these platforms, the extension of the piles below serving prin- 

 cipally to steady the whole. 



Cylindrical foundations are next referred to, commencing with 

 the primitive native Indian brick well, only large enough for a man 

 to work inside of, built on wooden curbs, often cemented by mud 

 only, and held together by straw ropes in sinking. Native divers 

 descend in them to a depth of seventeen feet below water, ex- 

 cavating and bringing up basketsful of sand, and numbers of 



