CA2225853A1

CA2225853A1 - Fabric reinforced beams and beam connections

Info

Publication number: CA2225853A1
Application number: CA002225853A
Authority: CA
Inventors: Frederick P. Isley; Edward R. Fyfe
Original assignee: Individual
Current assignee: Manufactured Technologies Co LLC
Priority date: 1995-06-29
Filing date: 1996-06-11
Publication date: 1997-01-16
Also published as: KR100397311B1; US5657595A; AU6267396A; KR19990028514A; NZ311362A; ATE225447T1; EP0835355B1; EP0835355A4; TR199701727T1; DE69624111T2; WO1997001686A1; EP0835355A1; JP2000508392A; DE69624111D1

Abstract

A technique for applying high strength fiber fabric to strengthen beams (12) and the connection between beams (12) and either supported platforms (10) or supporting vertical columns (14) is disclosed. Fabric made of high strength fibers such as glass, boron, or carbon, is laid over the connection between a beam (12) and a platform (10), or between a beam (12) and a supporting column (14), and impregnated with an epoxy resin or other polymer matrix. The fabric may be additionally fastened to the structural member using adhesives, fabric fasteners, or bolts. The invention is particularly well suited for retrofitting bridges, freeway overpasses, parking structures, and the like to prevent failure during an earthquake.

Description

CA 02225853 l997-l2-29 WO 97/01686 PCT~V~,~C~'6~.323 FABRIC REINFORCED BEAMS AND BEAM CONNECTIONS

BACKGROUND OF THE INVEN~ION

1. Field of the Invention The present invention relates to a method for l~infol~ ihlg structural :iU~)~ll~S and to reinforced structural :iU~ OllS. More particularly, the present invention relates to the use of high strength fabrics to reinforce beams and connf~ction~
be~ween beams and other structural members such as platforms, supports for decks, and ~up~olting columns and structures.

2. Back~;l uulld of the Related Art Construction mPthorl~ in which elevated platforms are supported by beams which are in turn supported by vertical columns, are used extensively in multilevel p~rking garages, bridges, freeway overpasses, multilevel commercial and recirlenti~l construction, and the like. The column~, beams, and platforms are often constructed of steel reinforced concrete.
During an earthquake or other event that produces atypical stresses, these concrete beams are particularly prone to fracture and ~p~lling where they are conn~ct~ to their supporting vertical columns and where they are connPcte~l to the elevated roadway platform. This is because structural members are often exposed to the greatest localized stresses at the point they connPct to other structuralmembers. Tests inrli~tP that when these members fail, fractures typically propagate at a 45~ angle from perpen~ ul~r connection~ Once a fracture has begun in a concrete member, it progresses rapidly. In an earthquake, continued ch~king can quicldy cause the fractured concrete m--mber to spall and crumble, res-llting incatastrophic failure. Even where the failure is not catastrophic, fractures in the structural members can col,lp,olllise the structural in~liLy such that the entire i structure must be demoli~hPcl and rebuilt at great cost. Also, beams and columnsmay be weak due to corrosion of reinforcing steel, increased weights on structure-sized design, the use of low-strength concrete in the original construction, and other prob~e~.
~lth-~ugh the sL~c g~l~ of structural mPmbPrs can be increased by increasing the size of those mPmhers, increasing the size of structural m~mhers used in elevated roadway construction is both extremely expensive and is inapplir~hle toretrofit work.
Recent events have demon~trated the vulner~bility of many PYi~ting structures to earthquakes. In the last 20 or so years, the area around Los Angeles, California has eY~-rienr~d an incl~ase in both the frequency and m~gnih~de of earthquakes.
It is eY~te~ that this increased seismic activity will co~ P or even increase still further. Accordingly, critical efforts are underway to identify methods of ~cLIor~lLiilg structures to improve their ductility and strength. Methods that do not change the stiffmps~ çh~r~rteri~tirs of the structure are highly pler~lrcd.
The use of high strength fabrics to reinforce vertical columns is known. One method of ~cinrol~ing vertical conclclc support column~ is set forth in United States Patent No. 5,043,033, issued to Fyfe. In this patent, the surface of a con~lcle column is wrapped with a composite m~tPri~l to form a hard annular shell surrounding the concrete column. The space between the outer composite shell andthe concrete column is then l~lcs~ulized by injecting a hardenable liquid.
Another approach to reinforcing the eYtPrior of an eYi~ting concrete support column is set forth in United States Patent No. 5,218,810, issued to Isley, Jr. In this patent, the eYterior surface of a concrete column is wrapped with a composite m~tPri~l to form a hard annular shell or sleeve which is in direct contact with the column surface.
Wrapped steel sheets are also used to reinforce vertical col~lmn~. In this method a steel sheet is wrapped around the coll~mn, with the ends of the steel sheet being welded or otherwise joined to form a c~ntinllQus steel band encircling thec~ lllmn One disadvantage to this method is that these steel wraps must be main-WO 97/01686 pcT/u~r~o~s~3 tained to prevent c41lusion. Another disadvantage is that this method increases the sl;rfi.P-~ of the .~ h~r.
None of these mPthf~l~ address the problem of lcillrfJl~ ing h-.. ;;~r~t;.l beams where they cQnnPct with vertical support col-lmn~ or roadway platforms. The topo-S logy of such connP~tif~n~ makes ~~fo- llg these cs~nn-~tion~ and structural mPmh~ers ~liffirlllt A need exists thc.~rol~G for a method to ~l~o...i~lly reinforce beam-to column and beam-to-platform conn~ and increase the ductility of stmctural mPmhers at and around those csnnP~tinnC both in new construction as well as in retrofit appli~tion~.
Accordingly, it is an object of this invention to provide .~ r~ ;ed structural c~n-lPcti.~n~.
It is a further object of this invention to provide a method of ~ fi~ g eYi~tin~ structures to provide ~-lrlition~l strength at bearn-to-column and beam-to-p~lrO~ connP~tion~
It is a further object of this invention to provide a structure with reinforced beam-to~olumn and beam-to-platform c~nnP~tinn~ for new construction.
It is a further object of this invention to reinforce structural beams along an axis that is a~lu~ tply 45~ from the angle of inl~iLion with a ~u~ Ling cr~ mn.
It is a further object of this invention to provide a means by which damaged structures may be repaired, thereby strength~ning them and obviating the need todemolich and reconstruct them.
These and other objects and features of the present invention will become better understood by reference to the following det~ilPd description when taken in col jun~;Lion with the ~rco,--l)~nying drawings.

SUMMARY OF THE INVENTION
A high sllell~lll CQI..l~ ;le m~tPri~l such as fiber glass fabric illll)rc~ Pd with a polymer matrix such as epoxy resin is affixed to a structural member at the point where the member i~ with another member, such that the same piece of composite m~tPri~l covers both members near the connP~tinn as well as covering WO 97101686 PCT/US~ a23 the conn~cti~n itself. Typically, the C4~pO~I~P m~t~ri~l is comrri~P~l of mllltirlP
layers, with at least one layer having fibers r~ri~-ntçd longitu(lin~lly 90~ from the direction in which fractures would otherwise typically propagate.
The c~ po~;~ç- m~tPn~l may be either formed at the work site by laying S resin~ d fabric over the beam cQnn~tion to be strP-ngthçne~17 or may be a shell that has been pre-formed and is applied to the structure in the field.
If the co-..~o~ile m~tPri~l is pre-formed, it is then ~tt~rhPd to the structure using adhesives, anchor bolts, or through bolts to hold it tightly to the structure.
If the c~ osi~- m~tPri~l is formed at the work site by laying fabric illlp~e~n~tP~
with resin over the structure, the resin serves ~ ition~lly to adhere the co~ o~iLe m~tPri~l to the structure, and the use of ~ritlition~l f~tPnPrs is optional.
The fabric spreads stresses out over the surface of the structural mPmhPr to which it is ~tt~rhPA, increasing the ductility of the mPmhPr Reinfolced in this way, the mpmbpr can now with~t~n~i much greater stresses before frartl-rin~ and sr~lling than could the unreinforced member.
In a first p~efelled emboflimpnt~ a composite ~;nfol~lllent layer is formed by laying cloth sections onto a beam and a platform supported on the beam. Prefer-ably, resin is il..~n~tçd within the fabric before the fabric is applied to the structural mPmhPr ~lter~tively, the fabric may be laid on the structural m~mbPr,and illl~ AI~ with resin thereaflel.
AlLelllaLi~ely, the colllpo~ile reinforcement layer may be a pre-formed shell in the shape of a flanged ch~nn~-l that is applied to the underside of a beam and a platform ~up~lL~d by the beam, so as to encase the çn~lose~ sides and bottom of the beam, and to cover at least a portion of the underside of the platform. The shell is afffi~ced securely to the beam and platform using adhesives, fabric f~tenPrs,anchor bolts, or through bolts. Once the shell sectir~ have been secured in place, the various sP~tinn~ can be connPctP~l together by l~min~ting ~ ition~l layers of fabric and resin over the spans between shell sections.
In a second p~fc;ll~d emboflimp-nt~ where beams and su~olLiilg c~ mn.~
meet in a "T" conn~ti~m~ these conn~ctiorls are reinforced by laying "T" shaped ~Prti~n~ of cloth over the cQnnPction The cloth is woven of 90~ mesh and is cut CA 02225853 l997-l2-29 WO 9'7JO16S6 PCT/U~ 823 on a 45~ bias, so that the fibers are aligned at +45~ from the axis of the su~ ing colllmn The fibers therefore provide .n~ ;nror~,-,ent for the beam perpen-dicular to the sarne i45~ angles at which the beam would most likely fracture inthe ~h~. e of rcillf~lce...~nt Unidire~tinn~l fabric is then laid or wla~ped over the S bias clo~. ~ rely, both layers of fabric may be unidirectio~l, with the fibers of the two layers ori~.nt~d perpendicular to each other. Again, the fabric may be illlplCg~led with resin either before or after it is applied to the structural mPmher.
In a third ~lcÇtllcd emb~lim~nt cloth made from prim~nly unidirectional fibers is wrapped on +45~ diagonals over the top and under the arms of a "T"
conn~ctinrl.
In a fourth pl~fcll~d embo~lim~nt~ the basic invention is mo-lifi~l so",c~l,at to stren~then and repair an already ~m~g~l structure. The d~m~ed structure is eY~min~ to det~ line fracture direction(s), and the fabric is s~l~cted7 cut, andapplied to provide ..,~xil,,~,, strength at an angle of 90~ relative to the fracture(s).
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a se~tit~n~l perspective drawing of an elevated roadway reinforced according to a first and second p,cfe"cd embodiment of the present invention.

FIG. 2 is a s~tion~l view taken along section 2-2 of FIG. 1, illustrating the use of fiber f~ten~rs with a first ~rcre,r~d embo~limPnt of the present invention.

FIG. 3 is a section~l view taken along section 2-2 of FIG. 1, ill~ g the use of bolts with a first ~lcfe.led embo~liml~nt of the present invention.
FIG. 4 is a SeSti~ n~1 view showing a reinforced column and beam, illllsl~ g the use of fiber roving to anchor the Co~ osi~e reinforcement layer to the structure.

FIG. 5 is a side elevation view of a beam and vertical support column reinforced according to a second plcf~llcd embodiment of the present invention.

WO 97/01686 PCT/US95~l~23 FIG. 6 is a side elevation view of a vertical support column and asso~ia~d h~.;,n~.l;.l mP.mbP.r reinforced according to a second ~cfel~cd-embotlim~nt of the present invention.

5FIGS. 7 and 8 are side elevation views of ~lt.~rn~tive second ~lcrt:lled e~ , in which the reinforcement incllldes unidirection~l fibers.

FIG. 9 is a side elevation view of a second ~leÇellcd embodiment of thepresent invention as applied to an "L" shaped support structure.
FIGS. 10 and 11 are side elevation views of ~lt~rn~tive second ~lcr~lled embo~im~nt as applied to an "L" shaped support structure, in which the rcinrc,r~,llent ine~ludes unidirection~l fibers.

15FIG. 12 is a side elevation view of a third plcrclled embodiment of the present invention.

FIG. 13 is a side elevation view of an alternative third prer~,lcd embodiment of the present invention.
FIG. 13A is a side elevation view of the structure shown in FIG. 8, taken from a dirre~cllt angle.

FIG. 14 is a side elevation view of a reinforced structural connP~tic)n~
25illll~tr~ting how the present invention may be mo~lifi~d to provide m~rimllm cinfo~elllent for an already damaged structural connection.

DETAILED DESCRIP'I'ION OF THE INVENTION
FIG. 1 shows a sectional view of an elevated roadway whose beam-to-30pl~lru~ll and beam-to~olumn conn~-tion~ have been reinforced according to the present invention. A r~d~ ;~y ~ orm 10 is supported by ho,;~ l beams 12, CA 02225853 l 997 - l 2 - 29 WO 97JO1686 PCT~U~ UJ~JD~3 Q which are in turn ~ Jpol~d by vertical support columns 14. A first high strength c~ os;l~ .eillfol~-,-ent layer 20 l~lrOl~s the col~ n between beam 12 and f ~ r~ 0. First cc,.. ~ e n ~ fo~ "ent layer 20 is applied underneath and around the sides of beam 12, and underneath platform 10. The cûmposite S l~lro~.. ent layer 20 is preferably formed by applying fabric il.. p~ d with resin to the structural member. Alternatively, co---posile reinrolce...ent layer 20 may be pre-formed in sP~tionC. If pre-formed se~tionc are used, seams 60 are spliced to~PthPr using lap splice pieces 62 comI)r1sPcl of se~tionC of fabric illl~le~ d with resin. For the lap splice pieces 62, as well as other areas where layer of fabric overlap, the layers should overlap at least 30 c~ntimptp-rs for corrosion L~lu~Lion and to provide maximum transverse strength.
ition~lly~ a second high strength composite leinr~-~,-,ent layer 40 reinforces the conn~tion between beam 12 and column 14. Second composite .~force",ent layer 40 is shown in greater detail in FIG. 5.
FIG. 2, talcen along section 2-2 in FIG. 1, shows a section of one beam 12 and part of platform 10. Before the reinrulcelllent layer 20 is applied, all corners 15 are preferably rounded to a minimum radius of 4 centimeters~ Fiber f~ctenPrs 28 help to secure colllposilc reinforcement layer 20 to the surface 13 of beam 12 and the surface 11 of platform 10. Fabric f~stPnP.r.s 28 are preferably configured as sleeves or strips to be inserted into predrilled cavities 32. Fabric f~ctenprs 28 include engagement portions 29 and anchored portions 30 that extend into cavities 32. After cavities 32 are formed, fabric f~ctenPrs 28 are partially inserted into cavities 32 so as to seat anchored portions 30 within cavities 32 against structural n~PmhPr 12. The anchored portions 30 are preferably illlple~ t~ with an adhesiveresin or other adhesive product. Once the resin-i"~lcgn~l~d anchored portions 30are pociti~ nP~l within cavities 32, a plug 34 is used to wedge the anchored portion 30 of each fabric f~ctenPr 28 into engagement with structural member 12. Plug 34is preferably formed from an elastomeric substance, e.g., rubber, that is co",paLible with the resin or other m~tPri~l with which anchored portions 30 are illlp~ tP~.While the use of an in situ plug in the ~n~horing system shown in FIG. 2 is ~nPr~lly ~fell~d, the ~n-hon~~ of anchored portions 30 may be accomplished willwu~ the use of an in situ plug by il"pl~ ~n~ g the anchored portions 30 with a resin which will adhere to the structural member 10 upon curing. ~lttom~tively~ a pre-formed hot melt plug can be used instead of a rubber plug 34 to seat anchored portions 30 in cavities 32, in which case the hot melt adhesive is melted in place by injectin$~ hot air into cavities 32 or using other sl~it~hle means.
After anchored portions 30 are seated within cavities 32, the fibers which e~ctend c,u~w~nl from face 13 of structural m~omber 12 are partially or totally scp~.~ted and then wet out with the plefe~red resin (if not wetted out already) to form engagement portions 29 and fanned out against face 13.
In an ~lt~m~tive ~ler~ d method (not shown) for ~nrhf~ring co-npo~i~
~~rorcel--ent layer 20 to structural member 12, the fabric layers of composite I~Ço~---ent layer 20 are provided with a~llul~;s co-r~onding to anchor receiving cavities 32. Upon placing the fabric layers in the desired positinn~ against face 13, çrlg~gem~nt portions 28 are drawn through the apertures and fanned out against the eYrose~ outer surface 21 of composite reinforcement layer 20.
FIG. 3 shows an alternative method of securing the co---~ inrol..x...ent layer 20 to the sLIuc;luial mPmher 12. Bolts 22 (only one of which is shown) extend through beam 12. If desired, the bolts 22 may be pl~llessed. Nuts 24 are tight~nPd down over washers 26 to a torque sl-ffici~nt to provide s~uring of the.~infol~el--ent layer 20 to the structural number 12. Fabric f~ten~rs of the type ill..~l,,.l~d in FIG. 2 secure the co---posi~ reinforcement layer 20 to platform 10.
Other m~thotls for ~llring co--~osile layer 20 to structural members 12 and 10 will be readily a~alent to those skilled in the art. For eY~mI)le~ threaded studs that extend through an a~llul~ in composit~- reinforcement layer 20 may be grouted into holes pre~irill~ into the structural members, and nuts and washers tightened over the studs to secure the composite reinforcement layer in place. Alternatively, the threaded studs may be secured using convention~l lead anchors. Similarly, bolts may be threaded into lead anchors inserted into pre~1rill~1 holes in the structural memhers.
FIG. 4 illllst~t~s yet another method of anchoring a composite r~infolce.. ent to t-h-e structure, using a roving rod made from fiberglass or other high strength fiber WO 97/01686 PCT/U~,- .$/~923 m~tPri~l A hole 154 is drilled through structural member 12. A fabric roving rod152 cQ~ ;ng many tiny fibers is then inserted through hole 154 and a c~l,~nding hole in fiber reinforcelllel-t layer 20, and the individual fibers 156 of roving 154 are then splayed out against outer surface 21 of fiber l~infol~e.,.ent layer 20. Individual fibers 156 are then adhered to outer surface 21 using a poly.-~ hleresinorotheradhesiveco-~ hlewithco...pos;ler~rol~e",e,l~layer 20. Where mnltipl~ co",posi~ r~inrcl~",e"~ layers are used, the individual roving fibers are preferably sandwiched between reinforcement layers. It is to be understood that any of the ~n~hQring means ~ cu~ed above may be used to secure the co,.. pos;le ~einfor~",el-t layer to the structural member in any of theconfig--r~tic-n~ and embo~lim~nt~ of the present invention ~i~cll~sed herein below.
~n r~ably, the outer surface 13 of beam 12 (or other structural mPmhe~) is p~ d for ,~inforci,lg by first cl~ning it thoroughly to remove dirt and other loose matter from its s~lrf~e It is often desirable though not nP~.C~ to coat the portion of the structural member to be leillror~ed with a prer~llcd resin beforeapplir~tinn of the resin-i",~ t~ fabric layers to the surface. If the surface isporous, it may be desirable to allow the resin to ~-~~ P- the surface before applying the resin-i",~le~ P~1 fabric layers to the structural mPmber.
The fabric used in composite reinforcing layer 20 may be either a single layer of cloth, or may be mllltiple layers. Where a single layer of cloth is used, it will often be desirable to use weft cloth cont~ining both hori70nt~1 and vertical fibers. Where m~lltiple layers of fabric are used, it will often be de~ hle to ~ltPrn~te the ori~nt~tion of the fibers to provide m~ximllm strength along m~lltiple axes.
FIG. 5 illustrates a second ple~t;lled embodiment of the present invention.
A first ~T" shaped piece of fabric 41 is applied over the "TH formed by the ,n~.~;Lion of beam 12 with support column 43. The cloth is cut on the bias so that the fibers are aligned +45~ relative to column 43, so as to provide ..~;........strength perpen~icul~r to the most likely fracture axis. The "T" shaped piece offabric may include a portion (not shown) that wraps un~1ern~th beam 45 to cover at least a portion of the underside of beam 45. A second "T" shaped piece of cloth, CA 02225853 l997-l2-29 WO 97/01686 PCTIU' ~ '~v3v2 which may eimil~rly include an undcl~lv~al)l)ing portion, is applied to the obverse side of the beam (not shown). Optionally, "L" shaped cloth pieces 42 are appliedto the sides of column 43 and on the un~lerei~les of beam 45. ('ol~-mn tie wrapping 44 cc...~ il-E prim~rily unidirectif~n~1 fibers is then wrapped around column 43 to S bind the "T" and ~L" shaped pieces 41 and 42 tightly to column 43. If the top surface of beam 45 is not in full contact with a deck above it, then ~ iti~ n~1 tie wraps 46 and 48 comrrieing unidire~tion~1 fabric pieces are wrapped around beam 45 to bind the "T and "Ln shaped pieces 40 and 42 tightly to beam 45. If the topof beam 45 is in full contact with a deck, then tie wraps 46 and 48 will be wrapped around only three sides of beam 45. As in the first embodiment illllstr~t~d in FIG.
2, the c~ o~ reinforcing layer may be ~ ition~11y secured by fabric f~etenlors, bolts, or the like.
It is to be understood that the present invention is equally applicable to ,cillro~;c a beam and column combin~tion whether the beam and column are formed ~p~ 1y and then connP~t~ together, or whether they are cast int~gr~l SO as to define a se~m1-oee unit. .C imil~rly, the present invention is equally applicable when the bearn and platforrn are cast intf~.gr~l FIG. 6 shows a hc-ri7Ont~11y ori~nted "T" structural connection ~cinfo~ced according to a second prefcl,ed embo lim~nt of the present invention. Vertical column 72 is co~nected to a cross member 74. Cross member 74 may be either a beam su~ g a load such as a roadway platform, or may be a cross support between vertical columns 72. When cross m.ombPr 74 is a cross support, it may bec~nne~ted to column 72 at some angle other than 90~. Bias-cut fabric section 61 wraps around at least two sides of cross member 74, and at least three sides of vertical cn1~1mn 72. Where possible, tie wraps 64, and 66 and 68, wrap completely around cross m~mher 74 and vertical column 72, respectively.
FIG. 7 shows an alternative reinforcement for a "T" structural connection, where "T" shaped fabric piece l l0 has fibers orient~oA per~n~ r to the axis of beam 130, and tie wrapping 120 has fibers oriented perpendicular to the axis of column 140.

WC~ 97~01686 PCT/U5~ '~323 FIG. 8 shows yet another ~ltPrn~tive reinforcement for a HTII ~iLIU~;lu~
connP~tion~ where nTH shaped fabric piece 112 has fibers o~iPnt~d along the axis of beam 132, and tie wrapping 122 has fibers oriPnte~ perpentlie~ r to the axis of column 142. One advantage to ori~Pnting the fibers of fabric piece 112 along theaxis of beam 132 is that this gives the beam ,.. xi.. ,.. ,. flP~--r~l strength.
FIG. 9 shows an "L" shaped conmP~tion betw_en a hc..;~nnt~l beam 78 and a vertical ~iU~ L column 76 reinforced according to the present invention. Bias-cut fabric section 81 wraps around three sides of the cross mPrnber to column connec-tion. Tie wraps 84 and 88 further anchor bias-cut fabric section 81.
FIGS. 10 and 11 show ~LH shaped connpctic)n~ leinfor~ed with unidirectio~
fibers. The ori~nt~tiQn of fibers pe~Fen~ r to the axis of the beam as shown in FIG. 11 result in m~Yimllm fleYIl~l strength of the beam.
FIG. 12 shows a third pr~rellcd embodiment of the present invention.
Notches 70 are provided in column 71. Fabric wraps 54 and 56 having predomi-nan~ly unidirectional fibers wrap around column 71, structural cross member 90, and wrap ~UppOl~S 50 and 52 having triangular cross section, to rcinfol~;e the co~n~tirn bt;lw~ll column 71 and cross m~mber 90. The unidirectional fibers of wraps 54 and 56 are oriented at ~45~ relative to the axis of column 71. Wrap ~uppo,~ 50 and 52 are preferably affixed to the structural members 71 and 90 using an adhesive before wraps 54 and 56 are applied. Wraps 54 and 56 preferably each col,lp,ise a contim1oll~ sheet of fabric wrapped around column 71 and cross member 90 mll1tipl~ ~mes. Where column 71 and cross member 90 are concrete and are cast int~.~ral in new construction, support blocks 52 may be cast as part of thecolumn and cross m.omb~or comhin~tic-n An alternative third prt;ft;llcd embodim~nt is shown in FIG. 13. The notches 70 and support blocks 50 of FIG. 12 are elimin~ted Wraps 54 and 56 wrap directly around column 73, as revealed more fully in FIG. 13A. Additio~l wraps may be added to provide further ~nchor~ge for wraps 54 and 56.
In all of the embo~liment~ of the present invention, the reinforcing co...l~s;lrmay be adhered to the structural member through the adhesive plopellies of the WO 97/01686 PCT/US~ 3 polymer matrix itself, an ~tldition~1 adhesive, fiber f~cten~rs~ or other ~nr~ ring me~ns as fiiscll~d above.
All of the embod;~ dçsçrihe~ above may be modifi~ if desired for retrofit and rep~ur of already d~m~ d structures. The ~m~ged structures is ~ in~ to ~l~l~- Ill;ne the actual fracture pattern present, and the cloth type, weave, fiber direction, and bias angle of cut are morlifi~1 to provide m~ximllm strength perp~n-lir,~ r to the pr~dolllinallt fracture axis or axes.
In FIG. 14, for eY~mp1e, fabric 9l is selected and cut on the bias so as to provide ..~ strength perpendicular to fracture lOO. Depenrling on the eYicting fracture pattern and the axis or axes in grealesl need of leillfcsl.;e~ nt the fabric chosen may contain unidirection~1 fibers, fibers interwoven at a 90~ angle, or fibers en at any desired angle. Ad-lition~l tie wrap layers may be added as descrihe~ above, for ~ldition~l anchorage.
The c~~ o~i~ m~t~ri~l should be fire resict~nt Comm~--rcially available co~ gc such as FIREGUARD may be used. ~lt~rn~tively, the resin in the c~-- pocile reillfc"~ll,ent layer may be illl~ç~-~t~d with an int~1mescent or a low tG...~ e mP1ting glass suitable for rendering the composite leil-rol~;e,--ent layer fire reCict~nt The molting glass preferably has a mPlting telllpel~tule of no more than about 800 degrees Fahrenheit. Where an int~1m~sce-nt is used, it is plef~lled that an inh~m~scent powder or liquid be added to both a thick~-~ed outer layer of epoxy and a coating paint. PYROPLUSn' ITM powder and PYROPLUS~ ITM
liquid, both available from Fire & Thermal Protection ~ngin~rs~ Inc., P~l~ul~, Tn~ n~, have been found to be suitable. The coating paint may be chosen to matchthe sull~uilding or historic concrete, to give a smooth or textured a~aldnce, or to meet other ~ th~tir. purposes as the al~;hilect directs.
A wide variety of composite m~t~.ri~l~ may be used. While fabric illl~,l~n~l~ with epoxy resin to reinfol.;e a concrete elevated roadway structure has been ill115tr~t~, those skilled in the art will a~l~;ate that the present invention may be used with a wide variety of fibers and polymer m~hice.s to reinforce a ~imil~rly wide variety of structllres.

CA 02225853 l997-l2-29 WO 97/01686 l'CTllJS~5'11 The fabric, for eY~mrlP, may be comrriced of glass, ~ , poly~r~mifl, boron, Kevlar, silica, quartz, ce-~mic, polyethylene, ~mi~l, or other fibers. A
wide variety of types of weaves and fiber orient~tionC may be used in the fabric.
The polymer matriY. with which the fabric is i,llp,~,.~t~ may be compri~ of S poly~L~r, epoxy, vinyl ester, cyanate, polyamide, or other polymer m~tric~es~ with ~~poxy being ~,cr~fred for most applic~tinnc~ Preferably, the fiber and polymer matrLlc are w~l~oof and ultraviolet light (UV) rçcict~nt Simil~rly, the structure to be reinforced need not be a roadway pl~tform ~u~ td by a beam that is in turn ~uwolLed by a vertical column. For PY~mple, the present invention could also be applied to a structure in which the beams support joists rather than a roadway, or in which columnc support a platform directly wil]~ou~ the use of beams. The present invention could also be used where the ing columnc are round. The present invention could further be used where the conn~ctinnc to be reinforced are: "cross" rather than NTN connPotionc; h-.. ;7r~
rather than vertical; or at an angle other than 90~, as is common in bridge support lafficework.
Accordingly, while several embo~liml~ntc have been shown to illll5tr~tt- the invention, it will be understood by those skilled in the art that various çh~ngPc and mo~1ifi-~tionc can be made therein without departing from the scope of the invention as defined in the appended claims and their a~lopliately construed legal equivalents.

Claims

What Is Claimed Is:

1. A reinforced structure wherein a platform is supported by beams and wherein said beams are in turn supported by columns, said reinforced structure comprising:
a structural platform having a lower surface;
at least one beam extending laterally under said structural platform, said beam having a top portion which is connected to said lower surface of said structural platform to provide support thereof, said beam also having two side surfaces and a bottom surface;
a support column having a top portion connected to the bottom surface of said beam, said support column also having one or more sides defining a column extending away from said beam; and composite material beam reinforcement means for reinforcing the connection of said structural platform to said beam.

2. A reinforced structure according to claim 1 wherein said composite beam material reinforcement means includes fire resistant means.

3. A reinforced structure according to claim 1 wherein said fire resistant means is selected from the group consisting of an intuminescent and a low temperature melting glass.

4. A reinforced structure according to claim 1 wherein said composite material beam reinforcement means comprises a composite material shell which comprises:
a beam encasement portion which covers the bottom surface and two side surfaces of said beam;

a structural platform portion which is integral with said beam encasement portion and which extends from said beam encasement portion so as to cover at least a portion of the lower surface of said structural platform;
means for securing said beam encasement portion to said beam; and means for securing said structural platform portion to said structural platform.

5. A reinforced structure according to claim 4 wherein said composite material shell comprises fibers in a polymer matrix.

6. A reinforced structure according to claim 5 wherein said fibers are selected from the group consisting of glass, carbon, boron, Kevlar, silica, quartz, ceramic, aramid, polyaramid, and polyethylene.

7. A reinforced structure according to claim 6 wherein said polymer matrix is selected from the group consisting of polyester, epoxy, vinyl ester, cyanate, and polyamide.

8. A reinforced structure according to claim 7 wherein said beam and said support column are comprised of steel reinforced concrete.

9. A reinforced structure according to claim 8 wherein said means for securing said beam encasement portion to said beam comprises fasteners which connect the beam encasement portion to the side surfaces of said beam.

10. A reinforced structure according to claim 9 wherein said means for securing said structural platform portion to said structural platform comprises fasteners which connect the structural platform portion to the lower surface of said structural platform.

11. A reinforced structure according to claim 1 which further includes composite material column reinforcement means for reinforcing the connection of said beam to said support column.

12. A method of reinforcing a structural member, a platform supported thereon, and the connection therebetween, the method comprising the step of:
applying a composite material comprising fibers in a polymer matrix so as to cover at least a portion of the connection between said structural member and said platform, and so as to further cover at least a portion of said structural member and at least a portion of said platform.

13. The method of claim 12 further comprising the step of:
adding a fire resistant substance to said polymer matrix.

14. The method of claim 13 wherein said fire resistant substance is selected from the group consisting of an intumescent and a low temperature melting glass.

15. The method of claim 12 wherein said composite material is pre-formed.

16. The method of claim 15 further comprising the step of:
affixing said composite material to said structural member and said platform using a method selected from the group consisting of adhesives, fabric fasteners, anchored bolts and anchored threaded rods.

17. The method of claim 12 wherein the step of applying a composite material comprises the steps of:
impregnating fibers with a polymer matrix; and applying said impregnated fibers to said structural member and said platform before said polymer matrix has substantially hardened.

18. The method of claim 17 wherein said structural member is a horizontal beam.

19. The method of claim 17 wherein said structural member is a vertical support column.

20. A reinforced structure wherein a platform is supported by beams and wherein said beams are in turn supported by columns, said reinforced structure comprising:
a structural platform having a lower surface;
at least one beam extending laterally under said structural platform, said beam having a top surface which contacts said lower surface of said structural platform to provide support thereof, said beam also having two side surfaces and a bottom surface;
a support column having a top surface in contact with the bottom surface of said beam, said support column also having one or more sides defining a column extending away from said beam; and composite material column reinforcement means for reinforcing the connection of said support column to said beam.

21. A reinforced structure according to claim 20 wherein said beam and said support column are comprised of steel reinforced concrete.

22. A reinforced structure according to claim 21 wherein said composite material column reinforcement means comprises a composite material wrapping which comprises:
composite material connection wrappings which cover the two side surfaces of said beam in the area where said beam is connected to said support column, said composite material connection wrappings also extending onto the side surfaces ofsaid support column;

first and second beam tie wrappings which each comprise a composite material, said first and second tie wrappings being wrapped around said composite material connection wrappings located on said beam on either side of the location where said beam connects to said support column; and a column tie wrapping which comprises a composite material which is wrapped around said composite material connection wrapping located on said support column.

23. A reinforced structure according to claim 22 wherein said composite material column reinforcement means further comprises:
a fire resistant substance selected from the group consisting of an intumescent and a low temperature melting glass.

24. A reinforced structure according to claim 22 wherein said beam has a longitudinal axis and said support column has a longitudinal axis, and wherein said composite material connection wrappings are comprised of fibers in a polymer matrix.

25. A reinforced structure according to claim 24 wherein said fibers are oriented at an angle of substantially plus and minus 45° with respect to the longitudinal axes of said beam and said support column.

26. A reinforced structure according to claim 24 wherein said fibers are oriented along the longitudinal axis of said beam.

27. A reinforced structure according to claim 24 wherein said fibers are oriented perpendicular to the axis of said beam.

28. A reinforced structure according to claim 24 wherein said first and second tie beam wrappings and said column tie wrapping comprise fabric containing substantially unidirectional fibers.

29. A reinforced structure according to claim 28 wherein said fibers in said composite material connection wrappings, said first and second beam tie wrappings and said column tie wrappings are selected from the group consisting of glass, carbon, boron, Kevlar, silica, quartz, ceramic, aramid, polyaramid, and polyethylene.

30. A reinforced structure according to claim 29 wherein said polymer matrix for said composite material connection wrappings is selected from the group consisting of polyester, epoxy, vinyl ester, cyanate, and polyamide.

31. A reinforced structure according to claim 20 which further includes composite material beam reinforcement means for reinforcing the connection of said structural platform to said beam.

32. A method of reinforcing a support column, a beam supported thereby, and the connection therebetween, the method comprising the step of:
applying a composite material comprising fibers in a polymer matrix so as to cover at least a portion of the connection between said support column and said beam, and so as to further cover at least a portion of said support column and at least a portion of said beam.

33. The method of claim 32 wherein the polymer matrix includes a fire resistant substance selected from the group consisting of an intumescent and a low temperature melting glass.

34. The method of claim 32 wherein the step of applying a composite material comprises the step of:
applying a first wrapping comprised of fibers impregnated with a polymer matrix to said beam, said support column, and the connection therebetween.

35. The method of claim 34 wherein said fibers are oriented at an angle of substantially plus and minus 45° with respect to the longitudinal axis of said beam and the longitudinal axis of said support column.

36. The method of claim 34 wherein said fibers are oriented along the longitudinal axis of said beam.

37. The method of claim 34 wherein said fibers are oriented perpendicular to the longitudinal axis of said beam.

38. The method of claim 34 wherein the step of applying a composite material further comprises:
tie wrapping substantially unidirectional fibers impregnated with a polymer matrix about the longitudinal axis of said beam, on either side of the location where said beam connects to said support column, and at least partially over the portion of said first wrapping extending onto said beam; and tie wrapping substantially unidirectional fibers impregnated with a polymer matrix about the longitudinal axis of said support column and over the portion of said first wrapping extending onto said support column.

39. A reinforced structure for supporting an elevated roadway comprising:
a support column having a longitudinal axis;
a structural cross member connected to said support column, said structural cross member having a longitudinal axis; and composite material column reinforcement means for reinforcing the connection of said support column to said structural cross member.

40. The reinforced structure of claim 39 wherein:
said composite material column reinforcement means includes a fire resistant substance selected from the group consisting of an intumescent and a low temperature melting glass.

41. The reinforced structure of claim 39 wherein:
said composite material column reinforcement means comprises:
composite material connection wrapping which covers at least a portion of the connection between said support column and said structural cross member, andfurther covers at least a portion of said support column and at least a portion of said cross member.

42. The reinforced structure of claim 41 wherein:
the longitudinal axis of said support column and the longitudinal axis of said structural cross member intersect at a 90° angle; and said composite material column connection wrapping comprises fibers in a polymer matrix.

43. The reinforced structure of claim 42 wherein said fibers are oriented substantially plus and minus 45° with respect to the longitudinal axes of said support column and said structural cross member.

44. The reinforced structure of claim 42 wherein said fibers are oriented along the longitudinal axis of said support column.

45. The reinforced structure of claim 42 wherein said fibers are oriented perpendicular to the longitudinal axis of said support column.

46. The reinforced structure of claim 42 wherein said composite material column reinforcement means further comprises:
a first tie wrapping which comprises substantially unidirectional fibers in a polymer matrix, said first tie wrapping being wrapped around said composite material connection wrapping located on said support column; and a second tie wrapping which comprises substantially unidirectional fibers in a polymer matrix, said second tie wrapping being wrapped around said composite material connection wrapping located on said structural cross member.

47. A reinforced structure for supporting an elevated roadway comprising:
a support column;
a cross member connected perpendicular to said support column at a first end of said cross member, said cross member having an upper and a lower surface, said cross member having a longitudinal axis;
a first wrap support comprising an elongate member of isosceles triangular cross section, said first wrap support abutting both said support column and theupper surface of said cross member;
a second wrap support comprising an elongate member of isosceles triangular cross section, said second wrap support abutting both said support column and the lower surface of said cross member;
composite reinforcement means for reinforcing the connection between said support column and said cross member, said composite reinforcement means comprising:
a first wrapping, said first wrapping being wrapped over said first wrap support and extending onto said support column at an angle of plus 45° with respect to the longitudinal axis of said cross member;
a second wrapping, said second wrapping being wrapped over said second wrap support and extending onto said support column at an angle of minus 45° with respect to the longitudinal axis of to said cross member.

48. The reinforced structure of claim 47, wherein:
said composite reinforcement means further comprises a fire resistant substance selected from the group consisting of an intumescent and a low temperature melting glass.

49. The reinforced structure of claim 47 wherein:
said first and second wrappings comprise substantially unidirectional fibers in a polymer matrix.

50. A method of reinforcing a fractured roadway support structure which exhibits an existing fracture pattern, the method comprising the steps of:
analyzing said existing fracture pattern to determine a selected axis; and applying a composite material to reinforce said fractured roadway support structure along said selected axis.

51. The method of claim 50 further comprising the steps of:
determining the predominant axis of said existing fracture pattern; and defining the selected axis to be perpendicular to said predominant axis of said existing fracture pattern.

52. The method of claim 51 wherein:
said composite material is comprised of fibers in a polymer matrix, said fibers having at least one predominant fiber orientation.

53. The method of claim 50 further comprising the steps of:
determining the most probable direction of future fracture propagation; and defining said selected axis to be perpendicular to said most probable direction of future fracture propagation.

54. A method of securing a composite reinforcement layer to a structural element, the method comprising the steps of:
forming a hole in a structural element;
applying a composite reinforcement layer to a surface of the structural element;
inserting a fiber roving rod into the hole, said fiber roving rod comprising a plurality of fibers;
splaying out the fibers of the fiber roving rod against the composite reinforcement layer; and adhering the splayed out fibers to the composite reinforcement layer.