US2952061A

US2952061A - Concrete beams

Info

Publication number: US2952061A
Application number: US637347A
Authority: US
Inventors: Douglas K Warner
Original assignee: Individual
Current assignee: Individual
Priority date: 1957-01-18
Filing date: 1957-01-18
Publication date: 1960-09-13
Anticipated expiration: 1977-09-13

Description

D. K. WARNER CONCRETE BEAMS Filed Jan. 18. 1957 Sept. 1.3, 1960 United Sttes Patent O CONCRETE BEAMS Douglas K. Warner, 1937 Panama Drive, Sarasota, Fla.

Filed Jan. 18, 1957, Ser. No. 637,347

1 Claim. (Cl. 2'5-154) My invention relates to improvements in concrete beams and in the method of supporting the forms for the beams with the reenforcing rods so that it may be unnecessary to drive and later break E piling for that purpose and so that the reenforcing rods may be given a prestress.

In the accompanying drawing Fig. 1 represents a vertical section of a concrete pile, its cap, and parts of two beams resting end to end on said cap.

Fig. 2 is a section at AA Fig. 1 through said cap and pile and an end view of the longer beam section.

Fig. 3 is a section through the center of span of the longer beam at BB Fig. 1.

Two heavy reenforcing steel rods 1 and 2 are shown to have quarter circle bends at the ends 3 where they are welded together. The lower rod 1 rests on concrete block 4 atop cap 5 which in turn has been cast atop the chipped oi pile 6 and locked in the latters reenforcing rods 6A. Two bolts 7 with hooked ends 8 are cast in the cap and are passed through holes in both sides of angle 9 which is welded to rod 2.

When nuts 10 atop bolts 7 are tightened, rod 2 becomes a suspension bridge which may support the forms by rods 11 passing through cross members 12, by tightening nuts 13, the rods 11 having been bent over the top of rod 2.

Lower rod 1 is also given a prestress by bolts 7 as it bends over block 4 while the latter tips down to a flat contact with the top of cap 5 thus enabling rod 1 to support its own weight across the span in a nearly horizontal position.

The bolt supported cross members 12 are fastened to frame members 14 which slope slightly outwardly upwardly. Members 14 extend below 12 and are held apart at a lower level by cross members 15 and thus support the form walls 17 aided by bracing 16 and 18.

Rod 19 is fastened to the curved end of rod 2 and protrudes through the end wall of the form at AA. After beam 20 has set and its forms have been removed, the portions of rods 7 still exposed may be burned off and the heavy rods set in place for beam 21, the upper rod in this case being stressed by tightening a nut on the single rod 19, there Ibeing no danger now of the heavy rods tipping sideways. If the new span is to be of the expansion type rod 19 may be burned in two after the concrete sets by entering a torch through space 22, a greased paper having been placed over cap 5.

After removing nuts 13 and lowering forms comprised of 12, 14, 15, 16, 17 and 18 bolts 7 are burned o inside the concrete and damp cement inserted in the holes.

I claim:

The method of forming a prestressed concrete structure comprising the steps of suspending reinforcing wires between spaced supports, said reinforcing wires having a suspension bridge type curvature, attaching temporary anchor means at opposed ends of said reinforcing wires and suspending forms the length of said structure from said wires, pouring concrete in said forms and thereby stressing said wires to near their elastic limit by the weight of said concrete and said forms; after the initial hardening of the concrete removing said forms and releasing said temporary anchor means from said reinforcing wires whereby the relief of tension in the ends of said wires will cause said ends land the concrete in which they are embedded to move centrally compressing the lower central portion of said concrete and reducing the previous extreme tension in the wires, whereby after further normal shrinkage of the concrete and resulting continued decrease in wire tension, due both to said shrinkage and said form removal, live loads may now be applied which are carried by both the reduction in compression and even small tension in the lower portion of the concrete in said structure and an increase in compression inthe upper portion thereof as well as by a relatively small and fatigue-safe increase in wire tension even though much smaller than usual weights of wire and concrete are employed.

References Cited in the file of this patent UNITED STATES PATENTS 467,141 Seely Jan. 12, 1892 738,496 Shields Sept. 8, 1903 763,513 Schmidt June 28, 1904 960,305 Gilbreth .Tune 7, 1910 1,325,261 Ortseiten Dec. 16, 1919 1,887,385 Wertz June 22, 1929 FOREIGN PATENTS 21,903 Great Britain of 1902 144,193 Great Britain of 1920