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Title: US5671573: Prestressed concrete joist
[ Derwent Title ]


Country: US United States of America

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20 pages

 
Inventor: Tadros, Maher K.; Omaha, NE
Einea, Amin; Omaha, NE
Saleh, Mohsen; Omaha, NE

Assignee: Board of Regents, University of Nebraska-Lincoln, Lincoln, NE
other patents from UNIVERSITY OF NEBRASKA, THE BOARD OF REGENTS OF (599755) (approx. 298)
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Published / Filed: 1997-09-30 / 1996-04-22

Application Number: US1996000635996

IPC Code: Advanced: B28B 7/00; B28B 23/06; E04B 5/04; E04B 5/23; E04C 3/20; E04C 3/26;
Core: B28B 23/02; E04B 5/17; more...
IPC-7: E04C 3/22; E04C 3/26; E04C 5/08;

ECLA Code: E04C3/26; B28B7/00B; B28B23/06; E04B5/04; E04B5/04S; E04B5/23; E04C3/20B;

U.S. Class: Current: 052/223.8; 052/334; 052/650.1; 052/691; 052/855;
Original: 052/223.8; 052/729.1; 052/650.1; 052/334; 052/691; 052/737.1; 052/740.1;

Field of Search: 052/223.8,223.1,650.1,636,634,334,729.1,729.2,737.1,740.1,690-691

Priority Number:
1996-04-22  US1996000635996

Abstract:     A precast, prestressed concrete joist having web openings through which mechanical and electrical equipment may pass. In an exemplary embodiment, the joist comprises generally horizontal opposite top and bottom concrete members with a concrete web interposed between them. This web may have openings through which mechanical and electrical equipment may pass. Prestress steel strands may extend lengthwise through both the top and bottom members to provide prestress in the concrete joist. The concrete joist may further comprise strand restraining devices for deflecting the prestress steel strands. The precast, prestressed concrete joist having a web opening may be constructed using a reusable casting apparatus. This casting apparatus comprises a prestressing bed onto which a frame may be mounted. The frame provides a means of applying tension to the prestress steel strands and of supporting prestress strand restraining devices. A mold comprising an outer form and web opening forms may be attached to the prestressing bed. This mold may be used to cast the joist. The web opening forms preferably comprise a plurality of blocks which may be specially shaped to be removably attached together and secured to the prestressing bed to increase or decrease the span and depth of the desired web openings. The precast, prestressed concrete joist may be fabricated by first assembling the frame on a prestressing bed. The mold may next be assembled inside the frame. Strand restraining devices may be bolted to the frame by threaded rods. Prestress strands may then be threaded through these strand restraining devices and anchored to the frame. A prestressing force may then be applied to the prestress strands. Concrete is then poured into the mold and allowed to cure. The frame and mold are removed from around the finished joist.

Attorney, Agent or Firm: Suiter & Associates PC ;

Primary / Asst. Examiners: Canfield, Robert;

Maintenance Status: E2 Expired  Check current status

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Family: Show 2 known family members

First Claim:
Show all 5 claims
We claim:     1. A precast, prestressed concrete joist comprising:
  • (a) generally horizontal top and bottom concrete members, said top member having a generally flat upper face and said bottom member having a generally flat bottom face, opposing left and right angled surfaces adjoining said top and bottom members wherein said top member forms two opposing prismatic ends,
  • (b) a concrete web interposed between said top and bottom members having at least one opening therein;
  • (c) one or more prestress steel strands extending lengthwise through the top member and prismatic ends; and
  • (d) one or more steel strands extending lengthwise between the prismatic ends through said left and right angled surfaces and said bottom member.


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Description: Show description

Forward References: Show 26 U.S. patent(s) that reference this one

       
U.S. References: Go to Result Set: All U.S. references   |  Forward references (26)   |   Backward references (25)   |   Citation Link

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Patent  Pub.Date  Inventor Assignee   Title
Get PDF - 3pp US1764134* 1930-06 Young    
Get PDF - 5pp US2049926  1936-08 Rafter   Stud and rafter
Get PDF - 11pp US2435998  1948-02 Cueni   Composite prestressed concrete beam and slab structure
Get PDF - 3pp US2912849* 1959-11 Wissinger    
Get PDF - 6pp US2925727* 1960-02 Harris et al.    
Get PDF - 6pp US3349527* 1967-10 Bruns    
Get PDF - 4pp US3398498  1968-08 Krauss   COMPOSITE STEEL TRUSS AND PRECAST CONCRETE SLAB AND BEAM UNITS
Get PDF - 5pp US3550332  1970-12 Wiesmann   CONSTRUCTION SYSTEM AND CONCRETE STRUCTURAL MEMBER THEREFOR
Get PDF - 9pp US3577504  1971-05 Lipski   METHOD OF MANUFACTURING A GIRDER WITH A WEB OF REINFORCED AND/OR PRESTRESSED CONCRETE
Get PDF - 14pp US3813834  1974-06 Davis, Jr.  Products Engineering, Inc. JOIST WITH NAILING STRIP AND POSITIONING MEMBERS
Get PDF - 12pp US3919824  1975-11 Davis, Jr.   Joist, structural element and devices used in making same
Get PDF - 12pp US4041664  1977-08 Davis, Jr.   Joist, structural element and devices used in making same
Get PDF - 16pp US4144690  1979-03 Avery  Aluma Building Systems Incorporated Concrete forming structures
Get PDF - 6pp US4251047  1981-02 Holtvogt  The Dayton Sure Grip & Shore Company Swivel hold-down device
Get PDF - 8pp US4259822  1981-04 McManus   Precast concrete joist system
Get PDF - 11pp US4295310  1981-10 McManus   Precast concrete joist composite system
Get PDF - 4pp US4455269  1984-06 Spamer et al.   Device and method for forming in situ horizontal concrete slabs
Get PDF - 5pp US4700519  1987-10 Person et al.  Person; Joel I. Composite floor system
Get PDF - 10pp US4715155  1987-12 Holtz   Keyable composite joist
Get PDF - 7pp US5072565  1991-12 Wilnau   Pre-cast concrete wall panel and joist assembly and method of construction
Get PDF - 8pp US5074095  1991-12 Wilnau   Pre-cast concrete panel and joist assembly and method of construction
Get PDF - 48pp US5113631  1992-05 DiGirolamo et al.   Structural system for supporting a building utilizing light weight steel framing for walls and hollow core concrete slabs for floors and method of making same
Get PDF - 7pp US5119614  1992-06 Rex  Superior Precast Concrete post reinforcing apparatus
Get PDF - 7pp US5305572  1994-04 Yee   Long span post-tensioned steel/concrete truss and method of making same
Get PDF - 10pp US5397096  1995-03 Nelson   Forming apparatus for concrete floors, ceilings and walls
  * some details unavailable
       
Foreign References:
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Publication Date IPC Code Assignee   Title
  CA0744518 1966-10       


Other Abstract Info: DERABS G1997-488486 DERABS G1997-488486 DERABS G2000-282205

Other References:
  • Title: Prestress Strand Restraining Devices, pp. 81 and 84, Pub. Dayton Superior Catalog.
  • Author: John M. Savage, et al., Title: Behavior and Design of Double Tees with Web Openings Date: Jan.-Feb. 1996, pp. 46-62, Pub.: PCI Journal. (18 pages) Cited by 2 patents [ISI abstract]


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