US2262120A

US2262120A - Building truss

Info

Publication number: US2262120A
Application number: US345491A
Authority: US
Inventors: Howard G Smits
Original assignee: PACIFIC IRON AND STEEL Co
Current assignee: PACIFIC IRON AND STEEL Co
Priority date: 1940-07-15
Filing date: 1940-07-15
Publication date: 1941-11-11
Anticipated expiration: 1958-11-11

Description

BUILDING TRUSS Filed July 15, 1.940

J1 vvc/wtm Elba/V420 6. SM/ rs W MWZ Patented Nov. 11, 1941 BUILDING TRUS S Howard G. Smits, Pasadena,

Calif., assignor to Pacific Iron and Steel Company, Los Angeles, Calif., a corporation of California Application July 15, 1940, Serial No. 345,491

6 Claims.

The present invention relates generally to building construction, and more specifically to structural steel trusses for buildings and the method of making the same. Such trusses are typically used as roof trusses in industrial buildings, but it will be understood that my invention is independent of any particular use to which the truss is put.

In the past, there have been various improvements in design and construction aimed at decreasing the expense of steel framework for buildings. In general, these changes have been directed either toward reducing the weight of material required, as by changing the size and shape of the members used to build up a truss, or toward reducing labor costs, as by using welding to replace riveted joints. Direct labor and material charges constitute almost the entire cost of the fabricated product; and consequently a saving in either class of charges produces a correspondingly large saving in the final cost.

Thus it becomes a general object of my invention to provide a truss of lighter weight for a given loading in order to reduce the quantity of steel required in a given situation compared with conventional trusses.

It is also an object of the invention to provide a novel method of fabricating a truss from structural members with less labor for a given truss than is required by conventional methods.

An added object is to accomplish the reduction in weight of material and fabrication labor without departing from standard sizes and shapes of structural members or standard shop practices, in order to retain old economies along with the new.

These objects are secured according to my invention by cutting the web of an I-beam, or similar standard member, parallel to the flanges, and then spreading the flanges apart to form the upper and lower chords of a truss which are integrally joined at the end of the truss. In a symmetrical truss, one flange and web section is cut at the center and the two lengths are bent away separately from the other flange. Heat is preferably applied at the region of the bend to facilitate the operation. The truss is completed by welding to the chords the usual trussing members to carry the loading,

There is produced by this novel method of fabrication a new type of truss in which the top and bottom chords disposed at an angle to each other, are integrally joined together at their intersection, which is normally near one end of the truss, since the structural member from which the chords are formed is split for only a portion of its length. The truss may be symmetrical, with the top chord having two lengths at an angle to each other in the completed truss, and each length intersecting the bottom chord at or near the end of the truss.

Since a truss may ordinarily be inverted, that is, turned upside down, the terms top and bottom as applied to chords are merely descriptive of a particular construction and are in no way limitative upon my invention.

My novel truss and method of making it have the particular advantage that they simplify the connection between the two chords, which is the most expensive part of a truss, by reducing the amount of material and labor necessary.

How the above objects and advantages of my invention, as well as others not specifically mentioned, are attained, will be more apparent from the following description and the annexed drawing, in which:

Fig. 1 is a side elevation of a symmetrical truss constructed in accord with my invention, showing how it may be incorporated in the building framework; and

Fig. 2 is an enlarged fragmentary elevation of the intersection of the two chords, the dot-dash lines indicating the original beam,

The truss designated generally at I0 in Fig. 1 is an inverted symmetrical truss, and is shown supporting a roof as a part of the building framework. The truss comprises a top chord l2 and a bottom chord having two lengths 14 disposed at an angle to each other and to top chord l2 which they intersect and join near the ends of the truss. At their junction, the top and bottom chords are integrally joined together as they are parts of the same original member. The two lengths of the bottom chord [4 are connected at the center of the truss by a gusset plate l5, as is conventional; and angles IE, or similar members, extend between the two chords to which the ends of the angles are attached, in order to carry the loading.

Truss I0 is shown as end by column [8 and at l9 on top of column 20. A tie member 2| extends between the truss at gusset plate I5 and column 20, as is conventional practice,

In fabricating the truss I0, an I-beam of proper size is selected, the dot-dash lines of Fig. 2 indicating outlines of this original beam. Then two holes 24 are punched or drilled in the web supported at its lower its upper end by I-beam 25 (only one hole is shown in Fig. 2) each hole end of the beam wherebeing located near the the chords of the truss are joined. Next the web is cut through at 26 parallel to the beam be closer to one flange than the other, making the T-shaped sections of unequal size,

Holes 2d are preferable, but not necessary.-

In consequence I eliminate the material used in connection plates and rivets and the labor of making the joint, and thereby am enabled to make very substantial savings in material and fabrication costs in comparison with standard practices. My novel truss can be built for a given load carrying capacity with less weight of material and lower labor costs while still using standard shapes and standard shop practices so that no particular new expenses are involved, but rather the advantage of all usual shop I economies may be obtained.

They prevent further tearing of cut 26 after the truss is loaded; but the same result may be accomplished by suitable reinforcement of the web.

One T-shaped flange section is cut through transversely to longitudinal cut 26, dividing it into two equal lengths M for the bottom chord. The web is heated locally in the area between a hole 24 and flange l4, and. then one length I4' is bent from the dot-dash position of Fig. 2 to the full line position. The other length I4 is similarly bent away from chord I2 to which it is still integrally joined at the point of intersection.

The truss is completed by welding in place gusset plate l5, which closes the gap between the ends of chord elements I4, and angles it, which hold the chord members in their spread-apart position to form the truss in a triangle.

My invention is not to be considered as limited to any particular use or location of the truss l0, since the shape and position of the tr ss may be varied widelywithout departing from the spirit of. my invention. The triangular truss I is shown in Fig. 1 as an independent unit spanning the distance between columns l8 and and supporting on its substantially straight chord l2 a portion, of the building roof. Truss H] can also be incorporated into a larger truss as a part thereof, as would be the case here if center column 26 were eliminated and the two ties 2| were conected directly when the latter would then become the lower chord of a larger truss spanning the distance between two side wall columns I8. Likewise, triangular truss l0 may be turned upside down from the position shown, in which case chords l4 and I2 are then top and bottom chords respectively. Of course both chords maybe bent from their initial position in the original beam; and a chord may be bent between its ends if desired.

It willalso be apparent that my invention may be utilized to, provide other shapes and sizes of trusses, whether symmetrical or not.

, While I have described the truss of my invention as being mad-e from an I-beam, it will be realized that any suitable structural member may be used; as for example those rolled shapes which are designed as H-beams, girder beams, and the like;

From the foregoing, the advantages of my invention will be fully understood, since it will be seen that I have eliminated the conventional type of built-up heel connection between the upper and lower chords of the truss. In a riveted truss,

the greatest single item of cost is this heel connection because of the large gusset plate and many rivets required. The same is also true of a welded connection since it is diflicult to make a neat, cheap, symmetrical joint using standard structural shapes with maximum economy of labor. In my novel truss this problem of connecting the upper and lower chords is entirely eliminated, since they are integrally joined together. 75

From the foregoing description, it will be understood that various changes in the shape and design of the truss and the method of making it may be made without departing from. the spirit and scope of the invention, and consequently it is to be understood that the above description is to be considered as illustrative of, rather than limitative upon the invention as defined in the appended claims.

I claim:

1. A. structural truss comprising a top chord and a bottom chord, one chord being substantially straight and the other chord comprising two lengths disposed at an angle to the first chord and to each other, the two chords being integrally joined together near the ends of the truss, both chords being formed from a single structural member by splitting the structural member for a portion of its length and spreading apart the split portions without elongation thereof to form the truss chords.

2. A structural truss of triangular shape comprising a top chord and a bottom chord, one chord being the longest side of the triangle and of T-shaped cross-section, and the other chord having two lengths of T-shaped cross-section at the other two sides of the triangle, the two lengths being connected together by an intermediatev member and being integrally joined to the first-mentioned chord near the ends of the truss, both chords being formed from a single structural member having two flanges connected by a Web by splitting the web for a portion of its length and spreading apart the split portions to form truss chords of substantially the same length as the original flanges.

3. The method of fabricating a building truss from an I-beam or the like having two parallel flanges connected by a web, that includes the steps of cutting the web parallel to the flanges for a portion only of its length from a position near one end of the beam to a position near the other end of the beam; transversely cutting one flange and attached web portion at a positionv intermediate the length of the flrst mentioned cut to form two lengths of flange each integrally joined at one end only to the other flange; and bending each length of the cut flange to dispose each one at an angle to the other flange for the full length of the cut portion.

4. The method of fabricating a building truss from an I-beam or the like having two parallel flanges connected by a web, that includes the steps of cutting a hole in the web near each end of the beam; cutting the Web between the holes; transversely cutting one flange and attached web portion intermediate the holes in the web to form two lengths of flange each integrally joined at one end only to the other flange; and bending each length of the cut flange to dispose each one at an angle to the other flange for the full length of the out portion.

5. A structural truss of triangular shape com-,

prising a first chord and a second chord, the first chord being an integral member throughout its length; and the second chord comprising two separated, substantially equal lengths disposed at an angle to each other and to the first chord, each length of the second chord being integrally joined to the first chord only near the end of the truss, both chords being formed from a single structural member by splitting the structural member longitudinally for a portion of its length and spreading apart the split portions in a manner to preserve the original lengths of the split portions.

6. A structural truss comprising a first chord and a second chord, the first chord being a continuous straight member throughout its length:

and the second chord comprising two continuous straight lengths disposed at an angle to the first chord and to each other, the outer end of each length of the second chord being integrally joined to the first chord near one end of the truss and the inner ends of the two chord lengths being spaced apart and connected by an intermediate member; both chords being formed from a single structural member by splitting the structural member longitudinally for a portion of its length to form two split portions joined integrally at one end only to a third portion, and spreading apart the split portions in a manner to preserve the original lengths of all portions.

HOWARD G. SMITS.