US3271008A

US3271008A - Apparatus for treating structural members

Info

Publication number: US3271008A
Application number: US333955A
Authority: US
Inventors: Krammer Robert
Original assignee: Taylor and Gaskin Inc
Current assignee: Taylor and Gaskin Inc
Priority date: 1963-12-27
Filing date: 1963-12-27
Publication date: 1966-09-06
Anticipated expiration: 1983-09-06

Description

Sept. 6, 1966 R. KRAMMER 3,

APPARATUS FOR TREATING STRUCTURAL MEMBERS Filed Dec. 27, 1963 4 Sheets-Sheet 1 134 54 gig-g l\\\\ l' 444/ 444/ ///////4 ,4 32 1, 1 ea 22 lac fi/gvAV/i/ EEEQLY I N VENTOR.

R0851? 7 ARAMMEI? 2414A 6 PM A T'T'ORA/A'YS Sept. 6, 1966 R. KRAMMER 3,271,008

APPARATUS FOR TREATING STRUCTURAL MEMBERS Filed Dec. 27,1963 7 4 Sheets-Sheet 2 I INVENTOR.

ROEA'A? men/ M 1? m i 2mg, 5 M4 ATTOR/VJYS' Sept. 6, 1966 R. KRAMMER APPARATUS FOR TREATING STRUCTURAL MEMBERS Filed Dec. 27. 1963 4 Sheets-Sheet 5 INVENTOR. I? 0867?? KRAM Mi 50$ 4 lmlm/ ATTORA IY-S Sept. 6, 1966 I R. KRAMMER APPARATUS FOR TREATING STRUCTURAL MEMBERS Filed Dec. 27, 1963 4 Sheets-Sheet 4 INVENTOR.

ROBIRT KFAMMER A TTOR/VIYS United States Patent 3,271,008 APPARATUS FOR TREATHNG STRUCTURAL IVIEMBERS Robert Krammer, Detroit, Mich, assignor to Taylor 8; Gaskin, Inc., Detroit, Mich, a corporation of Michigan Filed Dec. 27, 1963, Ser. No. 333,955 7 Claims. (Cl. 254-98) This invention relates to a method of and apparatus for stress relieving structural members while under load.

More particularly, it relates to a method of and apparatus for repairing, reinforcing or otherwise treating structural members such as girders, beams, trusses and arches while the members are under a lateral lo-ad. While the following description is concerned with the repair of a fabricated beam or girder, it will be apparent to those skilled in the are as the specification proceeds that the invention is not restricted thereto.

There are a number of conditions which necessitate the treatment of these structural members while under load. Probably the most frequently occurring is actual damage to the structural member which must be repaired to prevent failure of the member. Another condition may be increased trafiic load over a bridge, expressway overpass or the like, wherein it is desirable to reinforce the load bearing members to obviate the possibility of future damage and provide an adequate safety margin. Then too, there have been instances where the welds in a fabricated beam or girder are found to be defective after erection, and it is necessary to repair the defect before failure occurs.

It is of course desirable to effect the repair, reinforcement, etc. of these structural members without tearing down and rebuilding a portion of the structure already built. In addition, it is desirable to carry out the repair, etc. while the member is in a stress relieved condition in the area to be treated. The prior art methods of doing this have been both costly and time-consuming. For example, it has heretofore been the practice in repairing a bridge girder or beam to erect a foundation or crib underneath the bridge, and to employ jacks to raise the crib into engagement with the member, producing counterflexure of the member until it was in a substantially stress relieved condition. Obviously such an operation is very difiicult where the bridge spans a waterway or a deep gorge. With the advent of modern vehicular expressway, one can easily visualize the oonfusion and disruption of traflic that would result if such a method were used to effect repair of an expressway interchange overpass, for example.

It is therefore a general object to provide a method of stress relieving a localized area of a laterally loaded structural member by applying to the member adjacent opposite sides of the area, prestressing forces longitudinally of the member to stress relieve the member so that treatment can be effected while the localized area is in a substantially stress relieved condition.

Another object is the provision of a method of treating a localized area of a longitudinally extending laterally loaded flexural member having a web and a flange by securing to the flange on opposite sides of the area to be treated means for stress relieving the area and causing such means to apply forces longitudinally of the beam to prestress the member in said localized area so that treatment of the area may be effected while in a stress relieved condition.

A further object is the provision of apparatus for treating a localized area of a structural member such as a wide flange beam or girder of the described character including anchoring means for connection to the flange adjacent opposite sides of such area and means extending between and coupled to the anchoring means and provided with force applying mechanism for applying forces through the anchoring means longitudinally of the beam to stress relieve the forces of said lateral load in the area to be treated.

Another object is the provision of apparatus for repairing a localized area in the lower flange of a fabricated beam or girder under transverse load comprising pairs of rigid fingers embracing the beam flange on opposite sides of the web and carrying anchoring means secured to the upper and lower flange surfaces adjacent opposite sides of the localized area to be repaired, with means extending between each pair of fingers, and force applying means for urging the lower ends of the fingers together to compress the lower beam flange, which is under tension from the transverse load, thereby stress relieving the flange in the localized area to be repaired.

Other objects, advantages and meritorious features will more fully appear from the following specification, claims and accompanying drawings, wherein:

FIG. 1 is a cross-sectional view through a bridge span showing schematically apparatus embodying the invention positioned for engagement with one of the structural beams of the bridge which is to be repaired;

FIG. 2 is a side elevation of a portion of a structural beam to be repaired showing the apparatus of FIG. 1 positioned embracing the beam flange;

FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 2;

FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 3;

FIG. 5 is a cross-sectional view taken along line 55 of FIG. 3;

FIG. 6 is a side elevation of a portion of a structural beam showing a modified form of apparatus embodying the invention; and

FIG. 7 is a cross-sectional view taken along line 7-7 of FIG. 6.

In the following description the invention will be disclosed as having to do with the repair of a defective weld in the lower flange of a fabricated steel beam which constitutes one of the supporting members of a bridge or the like. As stated above, the common prior art practice has been to build a foundation or crib under the bridge and to utilize jacks or the like to support the defective beam and relieve the stress therein while the beam is being repaired.

There is shown in FIG. '1 generally schematically a bridge span having positioned thereon apparatus for repairing a structural beam without the necessity of building expensive and cumbersome foundations or cribs under the bridge. The bridge is shown as comprising a plurality of load bearing fabricated beams 20 which support a roadbed or the like 22 having at opposite sides thereof vertical abutments 24 surmounted by guardrails or the like as is common practice. Supported for movement longitudinally along the roadbed is an assembly including a truss 26 mounted on wheels or rollers 28, and having opposite end portions 30 overhanging the bridge. Suspended from the opposite truss ends 30 are hoist assemblies 32 which may be and preferably are motorized, and are coupled at their lower ends to the opposite ends of a second truss 34. A platform or the like 36 is supported on the truss 34 for rolling movement therealong on wheels 38, and such platform carries apparatus 40 for connection to a selected beam 20 to be repaired. As can be seen from BIG. 1, the apparatus '40 may be positioned in any desired location, as the entire assembly is movable longitudinally of the bridge and the platform carrying the apparatus is movable transversely of the bridge. Hence the assembly may be moved from one location to another easily and quickly without being dismantled should it be necessary to repair more than one of the beams 20, or to repair one beam in several places.

Considering FIGS. 2-5 inclusive, there is shown therein the apparatus 40 positioned embracing one of the beams 20 to be repaired or otherwise treated. In these Figs. the platform 36 and the

trusses

26 and 34 have been eliminated for the sake of clarity, but it is understood that the apparatus is supported adjacent the beam by means such as the assembly described above. The beam 20 comprises a web 44, an upper flange 42 and a lower flange 46, which last mentioned flange has a defeet to be repaired.

The apparatus 40 in general comprises two pairs of heavily constructed, rigid fingers shown at 48, 50, '2 and 54 which extend vertically on opposite sides of the beam embracing the lower flange 46. Each finger may be formed of steel plates or the like welded together as shown most clearly in FIG. 5. Tie rods 56 extend between each adjacent pair of fingers, e.g. 48 and 50; 52 and 54 near the upper ends thereof, and

additional tie rods

58 and 60 extend between the lower ends of each adjacent pair of fingers, with the

lower tie rods

58 and 60 projecting appreciably beyond one of the fingers as shown in FIGS. 2 and 5. Each tie rod is threaded at opposite ends and is provided with suitable nuts threadedly engaged thereon as shown at 62.

Referring to FIGS. 3 and 4, there are shown upper shoes 64 and 66 each including

opposite flange portions

68 and 70 bolted as at 72 to one of the inwardly facing plates of a

respective finger

48 and 52.

Fingers

50 and 54 also are provided with identical shoes, so a description of those shown will suffice for all. The bolts 72, in this case seven through each shoe flange, serve to rigidly secure each shoe to its respective finger in a position overhanging .the lower beam flange 46 as shown in FIG. 3. Bolted between

fingers

48 and 52 as by bolts 74 is a lower shoe 76 of rigid construction shown in cross section in FIG. 5. Another identical shoe 76 is bolted between

fingers

50 and 54.

Each of the four upper shoes, two of which are shown at 64 and 66, are provided with a coincally shaped lower end surface 78 (see FIGS. 3 and 4), while the upper ends of each lower shoe 76 and 76' are provided with a pair of spaced apart similarly shaped surfaces 80 and 82. With the apparatus 40 positioned embracing the beam 20, a wedge 84 may be interposed between each conical surface on the shoes and the beam flange 46 and wedged therebetween as by striking the larger wedge end with a hammer or the like. Each wedge 84 has a beam engaging surface 86 on one side thereof provided with serrations or teeth as shown in FIG. 3 to grip the beam flange, and an opposite spheroidal surface 88 engaging the conical surface on each shoe. The spheroidal surface on the wedges insures that each wedge will be securely engaged between the flange surface and a respective shoe even though some irregularities may be present in the flange surface.

Shown in FIGS. 2 and 5 are force applying means in the form of hydraulic rams or the like 90 and 92 having their base portions secured to the

fingers

50 and 54 respectively. Each pair of

tie rods

58 and 60 projects well beyond the

fingers

50 and 54, and through a heavy plate 94 having bearing pads 96 thereon. The hydraulic rams each includes a piston rod 98 having a spherical outer end 100 engaging a pad on the plate 94. The

tie rods

58 and 60 are additionally provided with safety nuts 102 threaded thereon adjacent the

fingers

50 and 54 so that if a failure should occur in that portion of the apparatus to the right of the nuts 102 in FIG. 2, the remaining parts of the apparatus would be retained in position.

To provide incremental adjustment of the lower shoes 76 and 76' with respect to their associated fingers, the

holes in the shoes through which the bolts project are vertically elongated, permitting limited vertical movement of the toes with respect to the fingers. FIGS. 3 and 4 show supports 104 welded to the fingers and having bolts 106 extending therethrough and abutting blocks 108 on the underside of the

shoes

76 and 76. Upon loosening of the bolts 74, the lower shoes rest on the bolts 106 and may be adjusted slightly vertically by manipulation of the bolts 106. As shown in FIG. 3 an aperture 110 is drilled through the web 42 of the beam 20 at the point of low stress, through which is passed a threaded rod 112 projecting through opposed

fingers

48 and 52, and nuts 114 threaded on the rod ends up against the fingers to hold them rigidly positioned so that the shoes and wedges will be maintained in the proper relationship with respect to the beam flange 46.

When a defect has been observed in the lower flange 46 of the beam 20 such as is indicated at X in FIG. 2, the assembly of FIG. 1 is mounted on the bridge as shown and moved therealong until the platform 36 is positioned disposing the apparatus 40 adjacent the area of the defect. As shown in dotted outline in FIG. 1, one pair of fingers such as 48 and 50 may be pivotally mounted on the platform 34 for swingable movement toward and away from the beam whereby the apparatus may be moved from beam to beam without disassembly.

With the

fingers

48, 50, 52 and 54 positioned embracing the beam flange 46 vertical adjustment of the whole apparatus is made to bring the

upper shoes

64 and 68 into proper position overhanging the flange. Then a suitable hole 110 is drilled through the web 44 and the rod 112 is inserted through the

fingers

48 and 52 and nuts 114 tightened. Another identical rod is similarly positioned between

fingers

50 and 54. Next if necessary, the bolts 74 securing lower shoes 76 and 76' to their respec tive fingers are loosened, and the shoes adjusted vertically by manipulation of the bolts 106 to properly align them with the flange 46, and bolts 74 tightened. The wedges 84 are then interposed between the flange 46 and the respective shoes and driven with a hammer or the like until they are urged to a position where their surfaces 86 grip the flange surface in non-slipping engagement. High pressure fluid is next introduced into the cylinders of rams 90 and 92 to extend piston rods 98. As can be seen from a review of FIG. 5, this places

tie rods

58 and 60 under tension and urges the lower ends of each pair of fingers toward each other, that is finger 48 is urged toward 50 and 52 is urged toward 54. This force is transmitted through the weges 84 to the beam flange 46, compressing the flange.

With the beam 20 transversely (or laterally) loaded, the portion of the lower beam flange 46 intermediate opposite ends thereof or between supports, is under tension. By applying compressive forces to the beam flange longitudinally thereof as above described, the defective area of the flange is stress relieved. While maintaining this stress relieved condition, the necessary repairs are effected, and thereafter the apparatus may be removed from the beam to allow the flange to assume its normally loaded condition. Referring to FIG. 3, the bolts 74 are loosened to permit the lower shoes 76 and 76' to drop away from the beam to allow removal of the wedges 84.

Turning now to FIGS. 6 and 7, there is shown another embodiment of the invention for repairing a defect indicated at X in the lower flange 46 of the fabricated beam 20.

In this embodiment, pairs of anchoring means or blocks shown at 120, 122, 124 and 126 in FIG. 6 are rigidly secured to the flange to be repaired as by welding. As can be seen in FIG. 6, each pair of blocks such as and 122 are welded to a surface of the flange 46 spaced adjacent opposite sides of the defect shown at X. Each block is bored as at 128 to accommodate a tie rod 130 which extends between and through each pair of blocks. Opposite ends of the tie rods are threaded as at 132 and are provided with nuts 134.

In addition to the two pairs of

blocks

120, 122 and 124, 126 shown in FIG. 6, there are two more corresponding pairs on the other side of the beam web 55, one of each pair being shown in FIG. 7 at 120' and 124'. Such are arranged on and secured to the beam flange 46 identically as the

blocks

120, 122, 124 and 126, and are similarly provided with tie rods 130 and nuts 134. Thus there are altogether four pairs of anchor blocks welded to the beam flange adjacent the opposite sides of the defective area X, with the tie rods 130 bridging such defective area.

To effect a repair at X, the nuts 134 are threaded on each tie rod 130 bearing against the blocks, thus placing the tie rods under tension and urging each pair of blocks such as 120 and 122 toward each other. As the beam 20 is tranversely loaded, the lower flange 46 will be under tension from such loading, and the tightening of nuts 134 applies longitudinal compressive forces to the beam flange, thus stress relieving the flange 46 in the area X. As the longitudinal forces are being applied, suit able measuring instruments such as strain gauges or the like may be used to measure the stress in the beam flange, and the force application is continued until the flange is under substantially zero stress, or at least within a permissible range, say plus or minus 10 percent. Suitable electrical and mechanical or optical strain gauges are commercially available, and need not be described or shown, as they form no part of the instant invention.

When the beam flange 46 in the area X has been prestressed or stress relieved, the applied forces are maintained While the flange is being repaired. When the repair has been completed, the nuts 134 are loosened and the beam allowed to assume its normal loaded condition. As certain stress concentrations may be set up in the flange by the welding of the blocks thereto, these are preferably cut off the flange and any weld metal deposits removed as by grinding after the repair is completed.

In the interest of clarity, the invention is defined in some, at least, of the following claims as concerning the treatment or repair of a beam. It is to be understood that the use of the term beam in such claims is intended as a generic term encompassing all of the structural members described hereinabove, rather than being restricted to a beam as distinguished from a girder, for example.

What is claimed is:

1. Apparatus for treating a longitudinally extending transversely loaded structural member having a web and a flange, comprising: opposed pairs of rigid fingers positioned adjacent opposite lateral edges of said flange with each pair of fingers being spaced from each other longitudinally along a flange edge adjacent opposite sides of a localized flange area to be treated; shoe members secured to said fingers having end portions overhanging the flange surfaces in spaced relation thereto; a plurality of wedge members interposed between said shoes and the flange surfaces frictionally held in non-slipping engagement against the flange surfaces; and force applying mechanism including means coupling together the fingers of each pair to urge said fingers in a direction to apply prestressing forces to the beam flange longitudinally of the beam to stress relieve the beam flange in said area to be treated.

2. Apparatus for treating a longitudinally extending transversely loaded structural member having a web and a flange, comprising: opposed pairs of rigid fingers positioned adjacent the opposite marginal edges of the flange generally perpendicularly to the plane of the flange, with the fingers of each pair being spaced from each other longitudinally of the beam adjacent opposite sides of a localized flange area to be treated; means extending between and connecting opposed fingers retaining the fingers in alignment laterally of the beam; shoe members connected to said fingers and carried thereby and having free end portions disposed in aligned confrontation with the upper and lower flange surfaces on opposite sides of said web; a plurality of wedge members interposed between said shoe end portions and said flange surfaces and wedged therebetween in non-slipping engagement with the flange; and force applying mechanism including means extending between and coupling together the fingers of each pair, said mechanism operable to urge the fingers in a direction applying prestressing forces to the beam flange longitudinally of the beam to stress relieve the flange in said area to be treated.

3. The invention as defined in claim 2 characterized in that said force applying mechanism comprises tie rod means extending between said fingers of each pair and means for tensioning said tie rod means to apply compressive prestressing forces to the flange longitudinally of the member to stresss relieve the flange in said localized area.

4. The invention as defined in claim 2 characterized in that said force applying mechanism comprises tie rods extending between each pair of fingers and fluid pressure operated cylinder and piston means operatively coupled to the tie rods to apply tension to the rods and applying compressive prestressing forces to the flange longitudinally of the beam to stress relieve the flange in said localized area.

5. The invention as defined in claim 2 characterized in that the free end portion of each shoe member confronting a flange surface defines a surface conforming to and cooperating with the mating surface of the wedge member interposed between said shoe end portion and said flange surface.

6. The invention defined in claim 5 characterized in that said each of said shoe member surfaces and said wedge member surfaces are conically curved.

7. The invention as defined in claim 2 characterized in that at least some of said shoe members are connected to said fingers by adjustable means for permitting limited adjustment of said shoe members longitudinally of the fingers, said means also including mechanism for locking the shoe members in any selected position.

References Cited by the Examiner UNITED STATES PATENTS 852,704 5/ 1907 Collins 29-33 1,032,721 7/1912 Woods et *al. 2933 1,673,179 6/1928 Bowman 254--43 1,714,187 5/1929 Pacy 29401 2,016,093 10/1935 Knight 29-40l 2,029,121 1/1936 Seeman et al 29401 2,485,280 10/ 1949 Grace 254-98 WILLIAM FELDMAN, Primary Examiner.

THOMAS H. EAGER, OTI-IELL M. SIMPSON,

Examiners.