US1963351A

US1963351A - Method of constructing foundations

Info

Publication number: US1963351A
Application number: US554620A
Authority: US
Inventors: Melville F Clements; Nick F Helmers
Original assignee: Individual
Current assignee: Individual
Priority date: 1931-08-03
Filing date: 1931-08-03
Publication date: 1934-06-19
Anticipated expiration: 1951-06-19

Description

June 19, 1934. M. F, CLEMENTS ET AL 1,963,351

METHOD OF CONSTRUCTING FOUNDATIONS Filed Aug. 3, 1931 2 Sheets-Sheet 1 amnion Mel Ville F'lemezzzs'.

flickii'iie lm era June 19, 1934. M. F. CLEMENTS ET AL METHOD OF CONSTRUCTING FOUNDATIONS Filed Aug. 3, 1931 2 Sheets-Sheet 2 I Ir w ywwmwa amnion, filelrz'lle'FClemenis Wick Ffle liner; %1 0L ammqo Patented June 19, 1934 UNITED STATES METHOD OF CONSTRUCTING FOUNDATIONS Melville F. Clements and Nick F. Helmers, St. Paul, Minn.

Application August 3, 1931, Serial No. 554,620

2 Claims.

Our invention relates to improvements in the method of constructing foundations and is particularly adapted for use in the construction of subaqueous foundations which have an extensive horizontal area.

It is the object of our invention to provide for the construction of a caisson of any desired type in multiple sections around a central or enclosed area and thus to facilitate the excavation for and building of the foundation in the central area.

It is also our object to'avoid the known difficulties of sinking a unitary or integral caisson of great horizontal dimensions.

Further objects of our invention are to provide a series of small caissons which, when joined together, form an outer wall or composite caisson, enclosing a central area to be excavated and filled; to so arrange the circumferential caissons that they may act as a support for an enclosed central chamber, and to provide a roof cover for this central chamber which will permit the preparing of the foundation beneath it by the open dredging method or the pneumatic method, or any other known method.

Referring to the drawings, Figure 1 is a plan View of our circumferential caissons and also shows diagrammatically a surrounding cofferdam; Figs. 2, 3 and 4 are vertical sections of caissons illustrated in Fig. 1 showing various phases in the progress of constructing a fo ndation by the method herein described; Fig. 2 showing the initial step in constructing two of the circumferential caissons; Fig. 3 showing the circumferential caissons sunk to bed rock, prior to the excavation of the central areas, and with the roof over said area in place and Fig. 4 illustrates a foundation completed according to our method and supporting the pier 15 of a bridge.

In the drawings, A represents bed rock, B ledge rock or other surface material overlaying the bed rock, C sand, silt or other fine material and D concrete.

The circumferential caissons of our foundation may be constructed by any known method, but we prefer to construct them in the open and upon a sand island from within a cofferdam. In carrying out our invention, we first build a cofferdam 10 surrounding the entire foundation to be constructed, as illustrated diagrammatically in Fig. 1; we then pump down the water within said cofferdam to a predetermined level of say fifty feet and fill the interior of the cofferdam with sand or other granular material to that level to permit building the caissons on a flat surface.

We then build on the island thus formed the first section (see Fig. 2) of caissons 1, 3, 5 and 7 (Fig. 1), and remove the sand and water to sink said sections. By placing a bulkhead 11 approximately seven feet above the cutting edge 12 of the several caissons, the use of the pneumatic method in completing the sinking of the caissons is made possible. We continue the building of successive sections of the caissons 1, 3, 5 and '7 above those already sunk and continue the dredging until the four caissons above designated are down to bed rock on which the foundation is to rest. We then construct and sink in the same Way caissons 2, 4, 6 and 8. The permanent material 13 to be added on the interior of each caisson is now placed. The openings 9 between the caissons are then cleaned and the caissons are united to form an integral wall by bonding them together and filling the openings with concrete, 9a..

The material in the central space within the wall formed by the caissons may now be removed by the open cut method. After this work has progressed to a level somewhat above bed rock, a roof 14 (Figs. 3 and 4), preferably consisting of a heavy slab of reinforced concrete, is placed over the central area and supported by the caissons so that the work of excavation may be completed by the pneumatic process.

Thus the chamber formed by the roof and the caissons is supplied with air under pressure to enable workmen in the chamber to excavate the material therein without interference from water which, in the absence of the pneumatic pressure, would find its way into the chamber.

During the construction of the caissons, reinforcing bars 15 are inbedded therein, adapted to project into the spaces- 9 between the caissons and also into the central area enclosed by the caisson wall. These reinforcing bars may be turned up against the caissons (see Fig. 3) during the process of sinking the same so as to reduce sliding resistance, and after the caissons have been sunk to their permanent position these bars 15 are bent outward to furnish a bond for the concrete in the spaces between the caissons and also to furnish a similar bond between the caisson wall and the central area within the wall which we finally fill with concrete to form a well bonded footing.

The utility and desirability of our method of constructing massive foundations is evident since it has been proposed to construct a pier 185 feet by feet in plan and resting on rock feet below the water surface. The use of a single caisson in the construction of such a pier foundation is inexpedient, if not impossible, because of cost and the engineering problems involved in fabricating, placing and sinking a caisson of so great dimensions.

Having described our invention, what we claim as new and desire to protect by Letters Patent is:

1. The method of constructing a foundation below water which consists in making and sinking to bed rock a series of circumferential caissons, filling the space between the several caissons and uniting the same to form an impervious outer wall, placing on said wall, above Water, a large, heavy roof adapted to withstand internal pneumatic pressure, filling the chamber formed by said wall and roof with air under pressure substantially above atmospheric pressure and then while maintaining air pressure above atmospheric therein, excavating the material beneath said roof and then filling the excavation with concrete or other suitable building material, and bonding it to the wall to form a solid foundation.

2. The method of constructing a foundation of large horizontal extent below water which consists in enclosing the entire area to be occupied by the foundation within a wall comprising a series of circumferential caissons, then covering the entire area enclosed by said wall by a roof adapted to withstand pneumatic pressure Within the chamber formed by said caissons and roof, filling said chamber with air under pressure substantially above atmospheric pressure and then while maintaining air pressure above atmospheric pressure, excavating the material beneath said roof and finally filling the excavation to form a solid foundation.

MELVILLE F. CLEMENTS. NICK F. HELMERS.