US3777433A - Lattice girder - Google Patents

Lattice girder Download PDF

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Publication number
US3777433A
US3777433A US00232981A US3777433DA US3777433A US 3777433 A US3777433 A US 3777433A US 00232981 A US00232981 A US 00232981A US 3777433D A US3777433D A US 3777433DA US 3777433 A US3777433 A US 3777433A
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US
United States
Prior art keywords
rods
girder
braces
extending
boom
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00232981A
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English (en)
Inventor
F Grebner
W Ehemann
W Kolsch
G Spindler
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Individual
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Individual
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Filing date
Publication date
Priority claimed from DE19691944626 external-priority patent/DE1944626A1/de
Priority claimed from DE19702010666 external-priority patent/DE2010666A1/de
Application filed by Individual filed Critical Individual
Application granted granted Critical
Publication of US3777433A publication Critical patent/US3777433A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C3/00—Structural elongated elements designed for load-supporting
    • E04C3/02—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces
    • E04C3/04—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of metal
    • E04C3/08—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of metal with apertured web, e.g. with a web consisting of bar-like components; Honeycomb girders
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21F—WORKING OR PROCESSING OF METAL WIRE
    • B21F27/00—Making wire network, i.e. wire nets
    • B21F27/12—Making special types or portions of network by methods or means specially adapted therefor
    • B21F27/20—Making special types or portions of network by methods or means specially adapted therefor of plaster-carrying network
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
    • E04C5/01—Reinforcing elements of metal, e.g. with non-structural coatings
    • E04C5/06—Reinforcing elements of metal, e.g. with non-structural coatings of high bending resistance, i.e. of essentially three-dimensional extent, e.g. lattice girders
    • E04C5/065—Light-weight girders, e.g. with precast parts
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C3/00—Structural elongated elements designed for load-supporting
    • E04C3/02—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces
    • E04C3/04—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of metal
    • E04C2003/0486—Truss like structures composed of separate truss elements
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C3/00—Structural elongated elements designed for load-supporting
    • E04C3/02—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces
    • E04C3/04—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of metal
    • E04C2003/0486—Truss like structures composed of separate truss elements
    • E04C2003/0495—Truss like structures composed of separate truss elements the truss elements being located in several non-parallel surfaces
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49616—Structural member making
    • Y10T29/49623—Static structure, e.g., a building component
    • Y10T29/49625—Openwork, e.g., a truss, joist, frame, lattice-type or box beam

Definitions

  • Appl 232,981 A lattice girder comprising an upper boom, a lower Related ,s Application Data boom and a plurality of braces interconnecting the [62] Division of Ser No 69 087 Sept 2 1970 booms, is produced from a grid of structural steel rods abandoned so that the braces extend in parallel planes oblique to perpendicular planes passing through the booms, the [30] Foreign Application priority Data rods being spot welded at their points of intersection.
  • PATENTEDBEI H I975 3.771433 SHEET 2 OF 4 INVENTORS FR/TL GREBNEK WILHELM KoLscl-l BY Hflkp SPINDLEIQ WALTER ENE/wan AGENT LATTICE GIRDER This is a division of application Ser. No. 69,087, filed Sept. 2, 1970, now abandoned.
  • Lattice girders comprising a lower boom, an upper boom and diagonally extending braces connecting the booms, as well as girder blanks therefor and methods of their manufacture are known. Many difficulties have been encountered in spot welding the braces to the booms and/or in bending the structural steel rods, which form the booms and the braces, to form the three-dimensional girders from the plane blanks.
  • transversely spaced, longitudinally extending steel rods and longitudinally spaced, transversely extending steel rods intersecting the longitudinally extending steel rods are prepared.
  • the longitudinally and transversely extending steel rods are fed to a spotwelding station in respective and adjacent parallel planes, and respective ones of the longitudinally extending rods are spot welded at this station to respective ones of the transversely extending rods at the points of intersection of the respective rods.
  • the transversely extending rods extend obliquely to the longitudinally extending rods.
  • the transversely extending rods of the mat or grid are then cut along longitudinally extending lines to produce longitudinally extending mat or grid sections including at least two of the longitudinally extending rods.
  • Each section is then bent about a longitudinally extending axis to produce a respective lattice girder.
  • the bending axis may be constituted by one of the longitudinally extending rods of the section or it may be in the region of such a rod.
  • the resultant lattice girder comprises an upper boom, a lower boom, and a plurality of braces interconnecting the booms, the braces extending in parallel planes which are oblique to perpendicular planes passing through the booms.
  • the plane mat or grid of structural steel rods which serves as a blank forproducing the lattice girders, comprises transversely spaced, longitudinally extending steel rods in one plane, wherein groups of at least two such rods form longitudinally extending sections, and the transverse spacing of adjacent rods of adjacent sections is smaller than the transverse spacing of adjacent rods of each section.
  • Longitudinally and equidistantly spaced, transversely extending steel rods extend obliquely to the longitudinally extending rods in a plane adjacent and parallel to the one plane. At their points of intersection, the rods are spot welded to each other.
  • Such plane mats may be prepared in simple spot welding machines to which the structural steel rods are fed in straight path and without prior bending of the transverse rods designed to form the braces of the lattice girder. Also, these transverse rods may be bent easily through 180 so that the conventional rod gages may be used in the manufacture of the girders.
  • any desired portion of the blank sections may be readily adapted to support heavier loads simply by feeding additional and more closely spaced transverse rods to the spot welding machine so as to produce stronger bracing portions at given locations of the girders.
  • Conventional lattice girders of the general type hereinabove described comprise one upper boom structural steel rod, two lower boom structural steel rods, and diagonalbraces interconnecting the booms, each brace consisting of a generally V-shaped structural steel rod.
  • the braces extend in planes which are oblique to the perpendicular planes passing through booms, which means that the rods of the braces must be bent into their V-shape in a transverse plane which is oblique to the axis of the brace rod. This makes the bending rather difficult and requires bending moments of considerable force produced by special machinery.
  • the second lower boom rod in the girder half which is being bent about this axis is supposed to force all the brace ends attached to this second lower boom rod to pass through the same bending path.
  • the gage of the brace rods is larger than that of the lower boom rods. Therefore, the opposite effect has been observed, i.e., the braces deform the lower boom rod into an undulant shape.
  • this difficulty has been avoided by providing only a single lower boom rod.
  • the ends of the braces have stubs extending beyond the lower boom, and these stubs have portions extending in the direction of the boom.
  • a first leg of the braces is connected to the single lower boom rod while the second leg extends freely into the plane of the lower boom. Both legs have the stub portions which support the transverse structural steel rods of a reinforcing mat or grid extending parallel to, and below, the lower boom.
  • the second brace leg of bentover half of the girder moves freely, rather than being restrained by a lower boom rod attached thereto, which makes the bending much easier.
  • the bentover part of the girder has no spot welds which may be deformed and damaged by bending.
  • the ends of the braces may carry detachable or fixed spacing elements, for instance of synthetic resin, to define the necessary thickness of the concrete slab attached to the girder.
  • These spacing elements may consist simply of perpendicularly projecting ends of the braces, which may be coated with synthetic resin or carry synthetic resin sleeves, so that the girders may rest on the bottom of the concrete form on these spacing elements.
  • the synthetic resin will protect the spacing elements against corrosion.
  • FIG. 1 is a top view of a structural steel mat or grid useful in the production of lattice girders according to this invention
  • FIG. 2 is a perspective view of a lattice girder consisting of a cut-out and expanded section of the mat or grid of FIG. 1;
  • FIG. 3 is a side view of the lattice girder of FIG. 2;
  • FIG. 4 is a transverse section of the lattice girder of FIG. 2;
  • FIG. 5 is a transverse section of the lattice girder after it has been pressed together'in a transverse direction;
  • FIG. 5a shows-a modified mat or grid for forming the girder of FIG. 5;
  • FIG. 6 is a side view of a modified lattice girder connected to a reinforcing mat or grid;
  • FIG. 7 is a schematic top view showing the feeding of the longitudinally and transversely extending structural steel rods of the mat or grid of FIG. 1 to a spot welding machine;
  • FIG. 8 is a side view of another embodiment of a lattice girder
  • FIG. 9 is a transverse section along line IIX of FIG. 8.
  • FIG. 10 is a perspective view of the girder of FIGS. 8 and 9, connected to a reinforcing mat or grid.
  • FIG. 1 shows transversely spaced, longitudinally extending structural steel rods 1.
  • the rods are formed into groups of three equidistantly spaced, parallel rods forming sections of the mat or grid, a smaller transverse spacing being provided between the longitudinally extending rods 1', 1' of adjacent sections.
  • the sections are cut apart along cut lines 3 or 3' or 3" between the closely spaced rods 1', 1', as will be explained more fully hereinafter.
  • rods 2 Longitudinally spaced, transversely extending structural steel rods 2 intersect the rods 1, the rods 2 lying in a plane immediately adjacent the plane of the rods 1 so that the rods contact each other at their points of intersection where they are spot welded to each other.
  • additional transverse rods 2' may be provided at desired distances between pairs of regular rods 2.
  • the feeding of the rods 1 and 2 to a spot welding machine 7 is schematically shown in FIG. 7.
  • the rods are spot-welded together to form the mat or grid of FIG. 1, whereupon it is cut into sections which provide blanks for the lattice girders. If the cut lines are centrally intermediate the longitudinally extending rods 1, 1' of adjacent sections, as shown at 3, the transversely extending braces of the resultant lattice girders will have stubs 4 laterally extending beyond the lower boom rods 1, 1' (see FIG. 4). If the cut lines extend close to the respective rods 1', 1', as shown at 3', the braces will end close to the lower booms. If the cut lines extend close to rods 1', 1' at alternating rods 2, as shown at 3", only alternating braces will have stubs 4.
  • each section is bent about a longitudinally extending axis formed by rod 1 or in the range of rod 1 to produce the lattice girder shown in FIGS. 2 and 3.
  • a girder is of triangular cross section and has a lower boom including a pair of lower boom rods 1, 1', an upper boom 1 and diagonally extending braces 2 connecting the upper boom to the lower boom.
  • Each brace extends in a plane which is oblique and transverse to the perpendicular planes passing through the booms of the girder, the braces extending from the outside of the lower rods over the upper boom.
  • the braces 2 of the lattice girder have been pressed together so that the lower boom rods 1', 1 contact each other.
  • the contacting lower boom rods may be spot-welded together so as to constitute a unitary lower girder boom.
  • the stubs 4 of the braces 2 have been bent over to provide support for a reinforcing grid or mat 5 mounted in a plane parallel to, and below, the lower boom of the lattice girder.
  • the transversely extending rods 6 of the reinforcing mat or grid are simply moved into the space between the bentover portions of stubs 4, which extend longitudinally, and the lower boom rods 1', 1' to support the reinforcement on the girder.
  • the spot welding method for making the mat or grid, which serves as the blank for the production of the lattice girders is schematically illustrated in FIG. 7.
  • the spot welding machine 7 may be fixedly mounted or it may be rotatable about a vertical axis 8. If rotatable, the longitudinally extending structural steel rods 1, 1' are fed to the machine in the direction of their extension, and the machine is then turned about axis 8 to a desired angle determining the oblique extension of the transverse rods 2 in respect of the longitudinal rods 1, i.e., the feeding direction of the transverse rods. If the machine is fixed, the feeding direction of the longitudinal rods 1 is chosen according to the desired angle, as shown by the oblique arrow in FIG. 7.
  • the girder of FIGS. 8 to 10 has an upper boom rod 1 and a single lower boom rod 1, the two booms being interconnected by diagonally extending braces 2 which again extend in a plane oblique and transverse to the perpendicular planes passing through the girder booms.
  • the stubs 4 of the braces are bent over to receive and support the transverse rods 6 of a reinforcing mat or grid 5.
  • the bend of the stubs 4 is preferably such that a wedgeshaped space is formed between the bent stubs and the lower boom 1' to hold the rods 6 securely.
  • the spot welds between the braces and the booms are shown at 10.
  • the stubs 4 ' may also be downwardly bent to provide a spacing element 11. If desired, these spacing elements may be protected against corrosion by a synthetic resin coating or sleeve.
  • a lattice girder comprising an upper boom, diagonally etending braces connected to the upper boom and having respective legs extending therefrom, the braces forming triangles whose apices are at the upper boom and whose leg ends define the bases of the triangles, a lower boom connected only to the ends of the brace legs on one side of the girder, the lower boom compris- 2.

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  • Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Joining Of Building Structures In Genera (AREA)
US00232981A 1969-09-03 1972-03-08 Lattice girder Expired - Lifetime US3777433A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19691944626 DE1944626A1 (de) 1969-09-03 1969-09-03 Verfahren zur Herstellung von Gittertraegern
DE19702010666 DE2010666A1 (de) 1970-03-06 1970-03-06 Räumlicher Gitterträger für Stahlbetonteile

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US3777433A true US3777433A (en) 1973-12-11

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US00232981A Expired - Lifetime US3777433A (en) 1969-09-03 1972-03-08 Lattice girder

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US (1) US3777433A (fr)
BE (1) BE755671A (fr)
FR (1) FR2060374B1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6637111B2 (en) * 1997-07-15 2003-10-28 Komatsu Ltd. Method for making a boom of an excavator
CN113210541A (zh) * 2021-05-07 2021-08-06 吉林建筑大学 一种制备平面桁架钢筋的主机构及其应用

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE1009977A3 (nl) * 1996-01-26 1997-11-04 Paesen Rudi Afstandhouder voor bewapening van wanden, vloeren, betonconstructies en dergelijke.

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US905056A (en) * 1907-01-22 1908-11-24 Edmond Coignet Armored concrete construction.
US2199152A (en) * 1937-01-27 1940-04-30 Alfred J Edge Building construction
US3036676A (en) * 1955-05-18 1962-05-29 Fritz Grebner Lattice girder
US3345793A (en) * 1963-07-10 1967-10-10 Cvikl Ernst Three-dimensional load-supporting structures and methods of producing such structures
US3475876A (en) * 1966-08-23 1969-11-04 Georgi Oroschakoff Staggered reinforcement for concrete structures

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1260103B (de) * 1956-12-03 1968-02-01 Erich Stockmann Im Querschnitt etwa dreieckfoermiger Traeger fuer die Montage und zur Bewehrung von Stahlbetondecken, insbesondere Rippendecken
DE1211781B (de) * 1958-01-07 1966-03-03 Herbert Ainedter Dipl Ing Fachwerktraeger zum Bewehren von Betonbauteilen

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US905056A (en) * 1907-01-22 1908-11-24 Edmond Coignet Armored concrete construction.
US2199152A (en) * 1937-01-27 1940-04-30 Alfred J Edge Building construction
US3036676A (en) * 1955-05-18 1962-05-29 Fritz Grebner Lattice girder
US3345793A (en) * 1963-07-10 1967-10-10 Cvikl Ernst Three-dimensional load-supporting structures and methods of producing such structures
US3475876A (en) * 1966-08-23 1969-11-04 Georgi Oroschakoff Staggered reinforcement for concrete structures

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6637111B2 (en) * 1997-07-15 2003-10-28 Komatsu Ltd. Method for making a boom of an excavator
CN113210541A (zh) * 2021-05-07 2021-08-06 吉林建筑大学 一种制备平面桁架钢筋的主机构及其应用
CN113210541B (zh) * 2021-05-07 2023-03-14 吉林建筑大学 一种制备平面桁架钢筋的主机构及其应用

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Publication number Publication date
FR2060374B1 (fr) 1974-07-12
BE755671A (fr) 1971-02-15
FR2060374A1 (fr) 1971-06-18

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