GB397065A - Improvements in or relating to caissons for or forming pier and like foundations - Google Patents

Abstract

397,065. Caissons for pier &c. foundations. DRAVO CONTRACTING CO., Dravo Building, Pittsburg, U.S.A.-(Assignees of Miller, J. S. ; c/o Dravo Contracting Co., Dravo Building, Pittsburg, U.S.A.) March 30, 1933, No. 9619. Convention date, June 10, 1932. [Class 68 (ii).] Relates to the sinking of multi-cellular caissons which are floated into position and sunk to form the foundations of piers or like structures. The Figure show part of a caisson comprising a bell which consists of a floor 2 and a rim 1, and forms an inverted pan of oblong shape ; coffer dam walls 3 rise from the rim 1, and dredging wells 4 surround orifices 4a in the floor 2. The rim 1 is reinforced with concrete ; the lower parts of the walls 3 are of steel, and the upper parts 3a are of timber, and are built as the caisson is sunk. The caisson is floated into position, and is weighted with concrete or masonry until the rim 1 rests on the river or sea bed, which is then excavated through the wells 4. As the excavation proceeds, the caisson, with the increasing load of masonry &c. sinks into the bed ; if it sinks unevenly, one or more of the wells 4 is sealed, and air is pumped in until the tendency to tip is corrected. The face of the wall erected behind the timber work may be stepped back to lighten the wall. When the sinking of the caisson is completed, it may be filled with concrete.