Experimental investigation and design of longitudinal shear reinforcement in composite edge beams

TerminologyA sp.b "cross-sectional area of bottom transverse reinforcementA sp.t "cross-sectional area of top transverse reinforcementA sv "cross-sectional area of transverse reinforcementb 0 "average width of concrete rib between steel sheeting ribsd "stud shank diameterDc "overall depth of composite slabEcm "concrete modulus of elasticityfck "characteristic concrete compressive strengthfcm "estimated (mean) concrete compressive strength

fu "tensile strength of stud steelfyr "reinforcement nominal yield stressh "height of stud after weldinghp "height of steel sheeting ribskt "stud shear resistance reduction factorNr "number of studs per panPRd "design shear resistances "transverse spacing of studscv "partial safety factor

Experimental investigation and designof longitudinal shear reinforcement incomposite edge beamsM PatrickUniversity of Western Sydney, Australia

SummaryThe development of a new reinforcing component isreported. Its primary function is to prevent a specialtype of longitudinal shear failure from occurring incomposite edge beams when profiled steel sheetingis laid transverse to the longitudinal axis of the steelbeam, and welded-stud shear connectors arefastened through the sheeting either directly or inpre-cut holes. This brittle failure mode, referred toin the literature as a rib shearing failure, compriseshorizontal splits that form in the concrete betweenthe tops of the steel ribs in pans where there areshear connectors, while the failure surface locally

avoids the studs by passing over their heads. It hasbeen reported in the literature to have occurred onnumerous occasions in push-out and beam tests,and is even shown to occur in tests on beamsincorporating typical Australian profiled steelsheeting products with narrow, widely spaced steelribs, and detailed in accordance with BritishStandard BS 5950, Part 3.1 and Eurocode 4, Part 1.1.It is now mandatory in Australian Standard AS 2327,Part 1 to reinforce against rib shearing failure.Other potentially important applications for thereinforcing component are also described.

Prog. Struct. Engng Mater. 2000; 2:196d217

Background

The concrete slab of a composite beam must havesufficient longitudinal shear capacity for thelongitudinal forces arising from the compressivestresses that develop across its width and within itsdepth to be transferred to the shear connectors.Transverse, horizontal reinforcement in the form ofwelded-wire fabric or deformed reinforcing bars isnormally provided for this purpose, and it must alsocontrol longitudinal splitting that develops along theline of the shear connectors[1].

The ribs of profiled steel sheeting laid transverselyacross the concrete flange of a composite beaminterrupt the flow of force from the concretecompressive stress zone to the shear connectors whichaffects the longitudinal shear design. A special type oflongitudinal shear failure referred to as a rib shearingfailure[2,3] has been found to occur in push-out and

composite beam tests when the specimens have narrowconcrete flanges incorporating open-rib profiled steelsheeting laid transverse to the steel beam.

Grant et al[4] observed rib shearing failures in simplysupported composite beam tests and referred to this ashorizontal rib cracking. Transverse reinforcementcomprising welded-wire fabric was placed at mid-height in the concrete cover slab, but was unable toprevent the failure from occurring. The average widthof each concrete rib, b0 , was either 1.5 or 2.0 times theheight of the sheeting ribs, hp. The slabs extended8 times the overall depth of the slab, Dc , on each side ofthe steel beam top flange. This width was intended tomaximise the ductility and strength of the shearconnection. The predominant failure mode wasreferred to as a punch-through failure with a failuresurface that initiates as a shear cone around theconnector and penetrates the slab to the top of theconcrete rib. It was explained that from there, the

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Copyright ^ 2000 John Wiley & Sons, Ltd. Prog. Struct. Engng Mater. 2000; 2:196d217

Fig. 1 Conventional longitudinal shear failure surface types [7]

failure surface propagated through the concrete ribalong a path of least resistance. In most of the tests itthen extended diagonally down terminating at thesheeting pans, and the sheeting had to be removed toexpose the failure. However, on occasions the crackextended horizontally along the tops of the sheetingribs and was visible at the edge of the slab. It wasknown that this failure mode (rib shearing failure)reduced the strength and ductility of the shearconnection and was to be avoided whenever possible.

Hawkins and Mitchell[2] observed rib shearingfailures in several monotonically loaded push-out testsinvolving narrow, 610 mm wide specimens with76 mm high profiled steel sheeting ribs laid transverseto the steel beam. They cited several much earlierinvestigations[5,6] involving full-scale beam tests whichshowed ‘that the strength of the (shear) connectionwas greatly affected by the rib geometry, with the ribshearing failures initiating as cracks at the corners ofthe ribs’. They describe this type of failure as brittleand explain that it can become critical if studs aregrouped together, particularly in a narrow (concrete)rib profile close to the edge of a slab. They found that itcan significantly reduce the strength and ductility ofthe shear connection, and stated that ‘no satisfactorymodel has been developed for predicting thecombinations of specimen width and rib heights thatmust be used to avoid rib shear(ing) failures’.

Lloyd & Wright[3] performed a series of push-outtests on specimens that incorporated trapezoidalprofiled steel sheeting and headed-stud shearconnectors. The specimens varied in width from 450 to1350 mm. They observed rib shearing failures, at leastto some degree, in all the 450 mm wide push-outspecimens they tested, in which welded-wire fabric wasplaced on top of the 50 mm high sheeting ribs. Theyproposed a method for predicting the critical breadth ofslab below which rib shearing failure will occur asdistinct from cone failure involving wedge-shapedcones of concrete left around the shear studs. Theydeduced for the arrangements they were testing, thatthe width of 450 mm was close to the limit below whichrib shearing failure became critical. Their tests showedthat cone failure can lead to significantly worse load}slipbehaviour than for a solid slab, with an uneven zoneapproximating to a plateau signifying failure, followedby a significant drop in load-carrying capacity. Theload}slip behaviour of specimens that failed by ribshearing failure was not specifically described. However,they proposed that the minimum edge distancedetermined using their formulae can be used in edge-beam design to prevent rib shearing failure.

Review of design provisions for longitudinalshear in edge beams

Rib shearing failure has been identified as a potentialmode of longitudinal shear failure in composite edge

beams in the newly revised Australian CompositeStructures Standard AS 2327, Part 1—SimplySupported Beams[7]. It is referred to in the Standard asa Type 4 longitudinal shear failure (or more correctly,failure of a Type 4 failure surface). The conditionsunder which it is assumed to occur, and the specialway in which the slab must then be reinforced inaccordance with the Standard, are described in a latersection.

The other three types of longitudinal shear failure(Types 1–3) that must be considered when designingto AS 2327.1 are more conventional. Transversereinforcement can be used for this purpose in bothinternal and edge beams, although any contributionthe steel sheeting makes in this regard mustconservatively be ignored unless it can be quantifiedby testing. This is different to British Standard BS 5950,Part 3.1[8], and the ENV version of Eurocode 4,Part 1.1[9] where transverse sheeting may bycalculation be included as part of Type1 reinforcement depending on its level of anchorage.Although some researchers feel that this is notcontroversial[10], the author is of the opinion thatfurther work is still required on this subject,particularly when the sheeting ribs are of a type thatcan readily separate away from the concrete anddistort grossly at ultimate load.

The longitudinal shear surface corresponding toeach of these failure types is described as follows inrelation to a beam with a composite slab (see Fig. 1):Type 1, where a vertical plane passes through the slab;Type 2, which is a combination of three orthogonalplanes which enclose the shear connectors, two ofwhich emanate from the slab bottom face; and Type 3,which is a combination of three planes which enclosethe shear connectors, either one or two of whichemanate from the top corners of the steel sheeting ribspassing through the transverse cross-section. Thecross-sectional area of the transverse reinforcement,Asv, which crosses these types of shear surfaces and isassumed to be effective in resisting longitudinal shearis given in the table in Fig. 1. Neither BS 5950:3.1 norEurocode 4 require Type 2 shear failure to beconsidered when the sheeting is transverse to the steel

LONGITUDINAL SHEAR REINFORCEMENT 197


Fig. 2 Standard edge beam details [8,9]

beam, because it is assumed that its effect is accountedfor empirically when calculating the design shearresistance of the studs. Neither, perhaps for the samereason, is Type 3 failure mentioned when the sheetingis parallel.

For edge beams, or beams adjacent to largeopenings, BS 5950:3.1 and Eurocode 4 require thetransverse reinforcement to consist of U-bars as shownin Fig. 2. This requirement only applies where thedistance from the edge of the concrete flange to thecentreline of the nearest row of shear connectors is lessthan 300 mm. The purpose of the U-bars is to fullyanchor the otherwise straight bars along the line of theshear connectors, and thus prevent longitudinalsplitting of the concrete flange[1]. Where headed studsare used, the distance from the edge of the concreteflange to the centre of the nearest stud should not beless than 6 times the nominal stud diameter, d. Also, inthis case the diameter of the U-bars should not be lessthan half the stud diameter. Johnson and Anderson[11]

explain that a critical case to be considered whendetermining the cross-sectional area of the U-bars iswhen they act as Type 1 reinforcement across potentialfailure surface x–x as shown in Fig. 2.

The use of profiled steel sheeting with the ribs laidperpendicular to the steel beam of a composite edgebeam is of particular interest to the discussion in thispaper. Johnson and Anderson further explain that norules are given about the effectiveness of the profiledsheeting to act as transverse reinforcement in this case.They state that the length needed to develop the fulltensile resistance of the profiled sheeting ina composite slab is often greater than 300 mm.However, it would be more accurate to state that it isalways much greater than 300 mm[12]. Therefore, thecontribution that the sheeting makes as transversereinforcement should normally be neglected whencalculating the size of the U-bars in accordance withBS 5950:3.1 and Eurocode 4. Similarly, sheeting with

ribs parallel to the free edge should not be assumed toresist longitudinal splitting of the slab[10,11].

Shear resistance and ductility of welded-stud shear connectors

The design shear resistance, PRd, of a welded-studshear connector in a solid slab can be calculated usingempirical formulae[7–9,13]. In Eurocode 4, for the usualcase of h/d54, PRd is calculated as the lesser valuefrom the following formulae, noting that these sameequations have been slightly modified to calculate thenominal shear resistance (cv"1) in AS 2327.1:

PRd"0.8fu (pd2/4)/cv (steel governs) (1)

PRd"0.29d2J(fckEcm)/cv (concrete governs) (2)

In a composite slab, the profiled steel sheeting mayaffect the shear resistance of a connector. Although it isactually possible for the strength of the shearconnection to increase beyond that of a solid slab if thesheeting is attached to the steel beam, this is ignored indesign. The approach taken has been to applya reduction factor (41.0) to solid-slab shearresistances to account for the presence of the sheeting.This approach of referencing solid-slab design valueshas been adopted in order to simplify design[14].However, it has the disadvantage of compounding theerrors associated with predicting the strength of theconnectors in these two forms of construction. Theorientation of the sheeting can have an effect on thevalue of the factor.

Numerous investigations have been undertaken todetermine appropriate empirical expressions for thereduction factor[4,14–17]. Many more recentinvestigations have confirmed that the expressionsproposed by Grant et al[4], which have been used indesign for many years[8,13,18], can beunconservative[10,14–17,19–22]. Clarification with regardto the use of off-centred studs has been necessary. Inthe case of all the studs placed in the unfavourablelocation, such that the zone of concrete in compressionin front of the stud is least, the effective width of theconcrete rib is assumed to be reduced. This can causea significant reduction in the design shear resistance ofthe studs, and consequently, a significant penaltywhen using profiles with a central stiffener in the pan.Johnson and Anderson[11] explain the basis on whichthe expressions in BS 5950:3.1 for ribs perpendicular tothe steel beam (for either one, two, or three or morestuds per pan), due to Grant et al, were modified forEurocode 4 to give the following:

kt"A0.7

JNrBAb0

hpB CAhhp!1BD41.0

(or 0.8 when Nr"2) (3)

The design shear resistance is calculated by takingthe lesser of eqs (1) and (2) (with fu4450 MPa) and

COMPOSITE CONSTRUCTION198


Fig. 3 Shear failure of wide concrete ribs: (a) assumed distributionof forces around failure cone [14], (b) reinforcement to strengthenfailure cone

multiplying this value by kt . Some restrictions thatapply to the use of Eq. (3) are that Nr is not to exceed2 in computations, hp485 mm, b0/hp51,h5hp#35 mm, s54d and the studs must be weldedthrough the steel sheeting.

In AS 2327.1, it has been possible to avoid reducingthe design shear resistance of shear connectors incomposite slabs. This is because geometric restrictionsapply to the types of profiled steel sheeting that maybe used. The major types of profiled steel sheetingproduced in Australia all have narrow re-entrant steelribs, and wide pans without a central stiffener[12],whereby, in accordance with AS 2327.1, welded studscan be placed at least 60 mm away from the steelsheeting ribs laid transverse to the steel beam. (Theratio of the average width of the concrete rib to thesteel rib height, b0/hp, is between 3.3 and 5.3 comparedwith a common overseas value of about 2.0[11].) Theirductility has been verified in push-out and beam tests,some of which have been reported[23]. Tests have alsoshown that groups of three welded-studs should notbe placed in the Australian sheeting pans since the topface of the concrete slab can fail suddenly by spallingwith a resulting lack of ductility. Therefore, inAS 2327.1 it is not permissible to place more than twostuds in a sheeting pan when the ribs are transverse.

A number of investigators have also recentlyexpressed concern about the low ductility thatconnectors may have in the presence of profiled steelsheeting.

Johnson & Anderson[11] explain that numericalanalyses show that the required slip or ductilitydemand on connectors increases with the span of thebeam and as the number of connectors is reduced. Onthis basis, limits were derived for the minimum degreeof shear connection at critical cross-sections asa function of span, which appear in Eurocode 4. Theydefine ductile connectors as those havinga characteristic slip capacity exceeding 6 mm, notingthat in accordance with Eurocode 4, the slip capacity ofa push-out specimen is the slip at which the load firstfalls below the characteristic value. Headed studs withan overall length after welding of at least 4 times theshank diameter, and with a diameter of not less than16 mm and not exceeding 22 mm may be consideredas ductile in Eurocode 4, noting that slip capacity ina solid slab increases with shank diameter[1].

Mottram & Johnson[16] found in a series of push-outtests in which the profiled steel sheeting ribs were laidtransverse to the steel beam, that the ductility of19 mm studs placed in pairs per pan was significantlyless than that of single studs. Many of the specimenstested did not satisfy the ductility requirement ofEurocode 4. However, Mottram and Johnson arguethat the use of two studs per pan is unlikely to result inlow degrees of shear connection, and that their limitedslip capacity is therefore less critical than their resultssuggest. The author disagrees with this argument,citing beams supporting heavy concentrated loads as

an example of when partial shear connection can existat a critical cross-section, despite connectors placed inpairs in every sheeting pan within the shear span. Thegreater ductility associated with single, centrallypositioned studs is recognised in Eurocode 4, which,subject to several other conditions also applying,relaxes the restrictions between minimum degree ofshear connection and span for this case.

Lawson[14] briefly mentions that pairs of studs oftenlead to less ductility. His focus, however, is to deriveformulae for calculating the reduction in shearresistance of welded studs due to transversely laidprofiled steel sheeting ribs. The shear connectors maybe placed either singularly or in pairs in each sheetingpan. In the case of stud pairs, an additional reductionis applied due to the lack of deformation capacity. Heproposes a model for predicting shear failure of wideconcrete ribs when the failure cone translates relativeto the slab (see Fig. 3a). Equilibrium of forces requirestension to develop in the concrete on the unloadedside of the shear connector, while shear is assumed toexist over the entire failure surface. An assumption ismade about the relative strengths of the concrete intension and shear. This model is of interest because itclearly demonstrates that reinforcing steel could beused to strengthen the slab to possibly avoid thisfailure mode (see Fig. 3b). Although otherinvestigators have identified similar failure surfaces,eg ref.[24], no cases appear to have been reported where



special-purpose reinforcement like that shown inFig. 3b has been used to prevent failure. According toLawson, eq. (3) should become:

kt"(h!hp#0.4b0)

h41.0 (Nr"1) (4)

kt"C(h!hp#0.4b0)

h D C(0.5s#h)

2h D40.8 (Nr"2)

(5)

Brittle rib shearing failure observed inpush-out and edge-beam tests

The extremely detrimental effect that a rib shearingfailure has on the load–slip behaviour of welded studsand the integrity of the shear connection in compositeedge beams, is dramatically illustrated by theexamples that follow.

It should be noted that in all the push-out and beamtests described in this section, the profiled steelsheeting was holed around the studs, whereby it didnot contribute to the shear resistance in any of thetests. This approach was taken since the studs weremanually welded to the steel beam in accordance withAS 2327.1, rather than being automatically welded.Thus, it was possible to specify the finished height ofthe studs more accurately, and also their resistancewas more reliable for the purpose of the experiments.

The tests are described in chronological order. Oncethe basic failure mode had been identified in push-outtests, it was decided to investigate when it occurred infull-scale composite beam tests.

PUSH-OUT TESTS ON A RE-ENTRANT PROFILE

Two 600 mm wide push-out specimens were tested ina special test-rig which allowed connectors to beplaced at one level and tested with a known tensileforce applied[25], although in these tests tensile forcewas absent. The 120 mm deep slabs incorporatedprofiled steel sheeting with dovetail ribs laidtransverse to the steel beam. They were heavilyreinforced against Type 1 and 2 longitudinal shearfailures with welded-wire fabric placed in two layerson top of the sheeting ribs and near the top face of eachslab, and were poured horizontally. The specimenswere nominally identical to each other, except that inone specimen the slabs had a single 95]19 mmdiameter stud in the centre of a sheeting pan, while inthe other the slabs had a pair of these studs positionedtransversely at 60 mm centres. The dovetail ribs were54 mm high, 32 mm wide at their top and 12 mm attheir base, and were spaced at 200 mm centres. Thecompressive cylinder strength of the concrete at thetime of the tests was 44.5 MPa in the specimen withsingle connectors, and 33.0 MPa in the other. Theaverage tensile strength of the stud material was452 MPa.

The inner part of the push-out specimen containingthe single studs is shown after testing in Fig. 4a, andthe path of the failure surface over the stud head andthrough the plane of the welded-wire fabric placed ontop of the sheeting ribs is clearly visible. Theappearance of the failure surface in the specimen withpairs of studs was similar. Both failures were clearlyby rib shearing. A crack appeared suddenly atmaximum load on the side of the slab, emanating fromthe edge of the dovetail rib on the unloaded side of theconnector, as expected from Fig. 3a. The load}slipcurves in Fig. 4b show that on both occasions, failureoccurred in a very brittle manner at a slip of much lessthan a millimetre, well below the Eurocode 4 slipcapacity of 6 mm. Slip was measured between theconcrete near the base of the connectors and the steelbeam. Accordingly, the studs were effectivelyundeformed after testing. It is interesting to note thatthe maximum shear force reached in each stud wasfairly similar, which is contrary to what one mighthave expected if only the shear strength of the concretewas important. Thus, the stiffness of the shearconnection appears to have influenced the behaviour.

PUSH-OUT TEST ON A TRAPEZOIDAL PROFILE

A 600 mm wide, one-sided push-out specimen wastested in another special test-rig[23]. The 175 mm deepslab incorporated profiled steel sheeting withtrapezoidal ribs laid transverse to the steel beam. Itwas heavily reinforced against Type 1 and 2longitudinal shear failures with welded-wire fabricplaced in two layers on top of the sheeting ribs andnear the top face of the slab, and was pouredhorizontally. Pairs of 110]19 mm diameter weldedstuds were placed in two adjacent sheeting pans, andwere staggered about a central stiffener at 60 mmcentres measured transversely. The 76 mm hightrapezoidal steel ribs were 120 mm wide at their top,and spaced at 305 mm centres with 120 mm widepans. The compressive cylinder strength of theconcrete at the time of the test was 26.5 MPa, and theaverage tensile strength of the stud material was435 MPa.

After testing, the slab of the push-out specimen wasleft in two pieces as shown in Fig. 5a. The shape of thefailure surface is clearly visible, noting that it haspassed over the stud heads. The failure was clearly byrib shearing. The load–slip curve in Fig. 5b shows onceagain that failure occurred in a very brittle manner,noting that the shear force reached a maximum ata slip of well less than a millimetre and then droppedaway suddenly.

SHORT-SPAN EDGE BEAM DETAILED IN ACCORDANCE

WITH BS 5950: PART 3.1 AND EUROCODE 4:PART 1.1The severe delamination of the cover slab of thecomposite beam shown in Fig. 6 occurred as a result of



Fig. 4 Push-out tests on re-entrant profile: (a) rib shearing failure, (b) loaddslip curves

a rib shearing failure over each pan along the beam.Horizontal cracks first appeared at slips of well lessthan a millimetre, and quickly developed, initiallyoccurring somewhat randomly over different pans,before finally linking together when the maximum sliphad reached approximately 1.5 mm. At the end of thetest, the maximum slip had only reached 2.5 mm. It isworth noting that the horizontal cracks did notpenetrate to the far side of the slab.

The beam was detailed in accordance with BS 5950:Part 3.1 and Eurocode 4 (see Fig. 2), noting that whilethe heavy, 16 mm diameter U-bars visible in Fig. 6asuccessfully controlled longitudinal splitting, theycould not prevent the rib shearing failure, andpossibly weakened the failure plane. Some detailsconcerning the test beam are as follows: its span was1800 mm; the steel beam was a 360UB56.7; the overalldepth of the concrete slab was 120 mm, it was

1500 mm wide and the overhang was 165 mm longmeasured from the edge of the steel beam top flange(thus easily satisfying the minimum overhangrequirement of BS 5950:3.1 and Eurocode 4); and two95]19 mm diameter welded studs were centred aboutthe web of the steel beam and spaced transversely at60 mm centres in each pan. The compressive cylinderstrength of the concrete at the time of the test was48.3 MPa, and the average tensile strength of the studmaterial was 435 MPa. The profiled steel sheetingused was the same as that described in relationto Fig. 4.

LONG-SPAN EDGE BEAM DETAILED IN ACCORDANCE

WITH AS 2327.1-1980 [18]

The photograph in Fig. 7 clearly shows that a ribshearing failure emanates in pans where shearconnectors are present. The 9.6 m beam had one



Fig. 5 Push-out test on trapezoidal profile: (a) rib shearing failure, (b) loaddslip curve

95]19 mm diameter welded stud in every secondsheeting pan. The beam was originally built witha 140 mm deep by 1200 mm wide concrete flange, andhad been tested close to failure in a number ofpositions with point loads[26]. Welded-wire fabric wasplaced on top of the sheeting ribs to act as Type 1 and2 longitudinal shear reinforcement, and was designedin accordance with AS 2327.1-1980[18] prior toAS 2327.1-1996 being available. Longitudinal slips inthe vicinity of 8 mm had occurred along the length ofthe beam when one side of the slab at one end of thebeam was cut longitudinally with a saw, leaving onlya 60 mm wide outstand measured from the edge of thesteel beam top flange. At this point, there wasabsolutely no sign of any horizontal crackscorresponding to rib shearing failure. However, oncethe beam was reloaded to a significant level, thehorizontal cracks developed rapidly on the side of theslab outstand into the pattern visible in Fig. 7.

Development of a reinforcing componentto prevent rib shearing failure

An experimental investigation was undertaken todevelop a standard reinforcing component that couldbe used with the major types of Australian profiledsteel sheeting to prevent a rib shearing or Type4 longitudinal shear failure from occurring in edgebeam situations.

EVOLUTION OF THE REINFORCING COMPONENT

Beam and push-out tests were conducted to triala number of different components. When the beamtest reported in ref.[26] was performed, companionpush-out tests were also conducted. However, thepush-out specimens were only 600 mm wide, half thatof the beam flange. Therefore, the concrete in thepush-out specimens was reinforced quite differently



Fig. 6 Short-span edge beam detailed to BS 5950:3.1 and Eurocode 4: (a) reinforcement, (b) delamination of cover slab

to that in the slab of the beam. Having experienceda rib shearing failure in the push-out specimen shownin Fig. 4, small ligatures were placed in between thesheeting ribs on each side of the welded stud. Theywere intended to reinforce the potential horizontalfailure plane passing over the tops of the sheeting ribs.By suppressing a rib shearing failure, a ductileresponse was obtained. The push-out specimen finally

failed at a slip of about 7 mm when a stud on one sideof the specimen sheared at its base just above the weldmetal. There was no sign of any cracking on the side ofthe push-out specimen. The shear connectors in thecomposite beam failed the same way. At the oppositeend of the beam where part of the concrete flange wascut away as described previously, slips of up to 10 mmwere recorded before stud fracture. The extra



Fig. 7 Long-span edge beam detailed to AS 2327.1-1980 [18]

reinforcement in the vicinity of the stud would explainwhy the slip at fracture was less in the push-outspecimen.

At this stage it was decided to develop a morepractical solution. A reinforcing chair was developedwhich could fit between the cross-wires of a standardreinforcing fabric, and locally reinforce the concretearound a pair of welded studs. The component can beseen in Fig. 8a prior to pouring the concrete. The beamis similar to that shown in Fig. 6a except that U-barswere not used. When the beam was tested, onlya portion of the cover slab delaminated (see Fig. 8b).The reinforcing chair managed to keep the concretearound the studs intact. However, it was clear that thecomponent would need to reinforce a wider area.

The next stage of the investigation involved testing600 mm wide push-out specimens with the mostconcentrated shear connection that can occur inpractice, viz., pairs of 19 mm welded studs in each panof the Australian profiled steel sheeting with theclosest spaced ribs. A 450 mm wide reinforcingcomponent was developed which fitted into the panwhere the connectors were located, and resembleda short piece of welded-wire fabric bent into aninverted C-shape (see Fig. 9a). A series of tests wasconducted in which the diameter of the wire in thecomponent was varied. Pairs of studs, cut out of threespecimens after being tested, are shown in Fig. 9b. Thepair on the far left show very little deformation aftera test on a specimen with a wire diameter too small toprevent rib shearing failure. In contrast, the pair on thefar right show double bending, indicative of far

greater utilisation of the studs, and were froma specimen with the largest wire diameter. Ribshearing failure did not occur in the specimen. Instead,the concrete punched through the sheeting rib ina Type 2 mode. The middle pair was tested with anintermediate wire size, and the studs are leaning overwith an intermediate level of deformation.

A prototype very similar to the final product wasdeveloped after these tests. It consisted of a waveformpiece of reinforcing fabric which could be laid directlyon the profiled steel sheeting once the studs wereplaced. The prototype was made from cold-reduced,plain wire with a nominal diameter of 6 mm anda nominal yield stress of 450 MPa. It is shown inFig. 10a, and was used in a beam similar to that shownin Fig. 6a, but without the U-bars present. Thelongitudinal section shown in Fig. 10b, which was cutthrough the slab at the completion of testing, showsthat the component managed to control the crackwidth and prevent a rib shearing failure. This test isdiscussed more later in the paper.

FINAL DESIGN OF THE REINFORCING COMPONENT

The reinforcing component is now producedcommercially in Australia[27]. It consists of a waveformpiece of welded-wire fabric made from cold-reduced,ribbed wire with a nominal diameter of 6 mm anda nominal yield stress of 500 MPa. Therefore, this wireis superior in both its bond properties and tensilestrength compared with the plain wire used in theearlier prototype. The two configurations adopted for



Fig. 8 Short-span edge beam with reinforcing chair: (a) reinforcement, (b) partial delamination of cover slab

use with the Australian profiles are shown in Fig. 11.The principles behind the design of the component arebroadly described as follows:

(i) The waveform longitudinal wires resemble theweb elements of a truss and repeatedly passthrough a horizontal plane that passes acrossthe tops of the sheeting ribs, which is part ofa potential longitudinal shear failure surface

that locally passes over the tops of the shearconnectors.

(ii) The transverse wires assist in anchoring thelongitudinal wires across the potential failuresurface, and also serve as Types 1 and2 reinforcement.

(iii) The lower transverse wires assist in confiningthe concrete between the shear connectors andthe steel rib on the compressive side of the stud,



Fig. 9 Push-out testing of first wide prototype: (a) reinforcing component around studs, (b) studs after testing

thereby increasing the resistance to punch-through (see later).

(iv) The spacing of the four longitudinal wires is150 mm, making the nominal overall width ofthe component 450 mm. A pair of welded studscan fit between two adjacent longitudinal wires.Each panel has a nominal length of 600 mmwith a mass of about 2 kg, while they could beproduced in much longer lengths.

(v) The panels are fitted into position once theshear connectors are installed, and linkedtogether to provide continuity of the

longitudinal wires. These wires sit directlyon the sheeting pans, and the panels donot have to be specially supported or heldin position. The last panel fitted may need tobe cut to length. Normally the panels arecentred over the steel beam (as in Fig. 11),but they can be placed off-centre or staggered,as appropriate, if the slab overhang is tooshort (see Fig. 12a), or if the sheeting ribs arenot exactly perpendicular to steel beam (seeFig. 12b), this latter situation requiring shortpanels.



Fig. 10 Prototype of reinforcing component: (a) placed in a beam, (b) section showing crack

(vi) The component is only produced with anoverall height of 95 mm, which allows it to fitwithin the minimum overall slab depth of120 mm stipulated in AS 2327.1 for the types ofAustralian profiled steel sheeting shown inFig. 12. Welded-wire fabric required for flexureor shrinkage and temperature effects can beplaced either directly on the reinforcingcomponent or supported on bar chairs.

Testing of the reinforcing component

Several series of tests were performed using push-outspecimens and beams to verify the adequacy of thefinal design of the reinforcing component prior to itgoing into production. The design was also used asa basis to write appropriate detailing rules forinclusion in AS 2327.1-1996, which are described in the



Fig. 11 Versions of reinforcing component produced in Australia: (a) 200 mm rib spacing, (b) 300 mm rib spacing

next section. Some tests to investigate using thereinforcing component in different applications havealso been conducted, and are described later in thepaper.

PUSH-OUT TESTS ON A RE-ENTRANT PROFILE

(REINFORCING COMPONENT INCLUDED)

Three nominally identical push-out specimens weretested which contained the reinforcing component

shown in Fig. 10a. Since the lower-strength plain wirewas used rather than the 500 MPa ribbed wire, thiswas a more critical test on the component. The sameprofiled steel sheeting was used as for the testcorresponding to Fig. 4. Two 95]19 mm diameterwelded studs were placed in the middle of eachsheeting pan. The specimens were all cast from thesame batch of concrete and tested at different ageswhen the compressive cylinder strength of theconcrete was 18.0, 26.5 and 33.0 MPa. There was no



Fig. 12 Alternative positions for reinforcing component: (a)off-centred, (b) staggered

Fig. 13 Load-slip curves with reinforcing component: (a) re-entrant profile, (b) trapezoidal profilesign of a rib shearing failure in any of the tests. The

load}slip curves are shown in Fig. 13a, and the vastimprovement in ductility is evident compared withthe curve for two studs in Fig. 4b. However, the shearconnectors did not fracture in any of the tests,although they were severely distorted (cf. Fig. 9b).This was partly due to the weakening effect of thedovetail ribs, but also because in the final stages of thetest the top face of the concrete slab was thrust out.

PUSH-OUT TEST ON A TRAPEZOIDAL PROFILE

(REINFORCING COMPONENT INCLUDED)

A nominally identical push-out specimen was pouredand tested at the same time as the one correspondingto Fig. 5, except that it contained a version of thereinforcing component shown in Fig. 10a that hadbeen modified to suit the trapezoidal profile. At nostage during the test did any cracks appearcorresponding to rib shearing failure, and the vastimprovement in ductility is evident by comparing theload}slip curve in Fig. 13b with that in Fig. 5b. Itshould be pointed out that 8 mm diameter wires wereused to make the component for this test, whichproved to be conservative. It was not possible tofracture the studs.

SHORT-SPAN EDGE BEAMS (REINFORCING COMPONENT

INCLUDED)

A beam similar to that shown in Fig. 8a wasconstructed which included the reinforcingcomponent in Fig. 11a. Naturally, the U-bars wereomitted. In contrast with the failures shown in Figs 6b

and 8b, by the completion of testing only one very finehorizontal crack had appeared on the side of the beamover one of the pans. Also, a much larger longitudinalslip of 4.3 mm was attained. Unfortunately, it was notpossible to develop more slip because the compositebeam failed prematurely by the concrete crushing inthe vicinity of the loading point, by which time thesteel beam was extensively yielded. It was evident bythe end of the test that the shear connection was stillfully effective, and that the reinforcing component hadprevented a rib shearing failure from occurring.

Another nominally identical beam was constructedwhich included the reinforcing component in Fig. 11b.The beam behaved in a similar manner except that thehorizontal cracking was not visible at any point on theside of the concrete flange, and could only be seen bysectioning the slab (see Fig. 10b). It is interesting tonote that the rib shearing crack formed despite thewide (300 mm) concrete ribs and the very narrow steelsheeting ribs.

LONG-SPAN EDGE BEAM (REINFORCING COMPONENT

INCLUDED)

A detailed investigation was made of the behaviour ofthe shear connection in a composite beam at thestrength limit state[23]. The beam, with a span of 9.6 m,was very similar to that described previously andreported in ref.[26], except for some notable exceptions,viz.:



Fig. 14 Beam reinforcement: (a) northern end with fabric, (b) southern end with reinforcing component

d as shown in Figs 14a and b, respectively, thenorthern end of the beam was reinforcedconventionally with welded-wire fabric, while thesouthern end included panels of the reinforcingcomponent shown in Fig. 11a; and

d pairs of 95]19 mm diameter welded studs wereautomatically welded through the profiled steelsheeting in the middle of every second pan at60 mm centres measured transversely.

The beam was rigorously tested. The final stagesincluded a series of moment capacity tests when bothends of the beam were tested separately by applyinga single concentrated load. A number of the studsfractured at the southern end of the beam. The slipreached 11 mm before the first fracture, indicatinggood ductility of the shear connection. The maximumslip at the northern end reached a similar magnitudebut no studs fractured. Both the southern and northern



Fig. 15 Slab sections: (a) northern end showing rib shearing failure, (b) southern end without rib shearing failure [23]

ends exhibited similar strengths, although themoments reached at the southern end wereconsistently slightly higher, presumably because ofthe reinforcing component.

Once all testing was completed, the slab was cutlongitudinally at each end of the beam, very close tothe steel beam top flange. At the southern end (seeFig. 15b), the reinforcing component had completely

prevented a rib shearing failure from occurring, andno horizontal cracks were visible in the concrete. (Theinclined cracks in Fig. 15b, which extend between thetop of the dovetail ribs and the sheeting pans, occurredwhere the shear connectors thrust against the dovetailribs and caused bulging to occur.) In contrast, withoutthe reinforcing component present the horizontalcracks formed in the northern end (see Fig. 15a). It is



Fig. 16 Type 4 longitudinal shear: (a) failure surface, (b) reinforcement [7]

interesting to note that two cracks which would haveformed in alternate pans where the studs were locatedhave joined up to extend across the three pans adjacentto where the transverse cut was made in the slab.Small portions of these cracks were just visible on theexposed sides of the slab immediately prior to cutting,indicating that the horizontal cracks extended over thefull-width of the slab. Although the cracks only hada slight effect on the behaviour of the beam, it isa requirement in AS 2327.1 that edge beamsincorporating two welded-stud shear connectors intransversely laid sheeting pans must be reinforcedagainst rib shearing failure irrespective of the width ofthe slab outstand (see below).

Design rules in AS 2327.1-1996 forpreventing rib shearing failure incomposite edge beams

Design rules for preventing rib shearing failure incomposite edge beams with profiled steel sheetingdeemed perpendicular to the steel beam are given inSection 9, Transfer of Longitudinal Shear in Concreteof AS 2327.1. They are the first rules of their typeknown to be in existence. As mentioned previously,a rib shearing failure is classified as a Type 4

longitudinal shear failure in the Standard. A Type 4longitudinal shear surface is described in AS 2327.1,with reference to Fig. 16, as a horizontal plane whichpasses across the tops of the steel sheeting ribs in a compositeslab in which the sheeting ribs are deemed perpendicular tothe beam, locally avoiding the shear connectors by passingover their tops, and which extends from the outside verticalface of a slab outstand in a composite edge beam andcontinues some distance into the adjacent slab. It should benoted in Fig. 16a that the sheeting extends fully acrossthe flange of the steel beam. Also, the outstand of theconcrete slab which forms part of the flange ofa composite edge beam must be at least 150 mm widemeasured from the vertical outside edge of the slab tothe closest edge of the nearest connector (see Fig. 16a).This satisfies the requirement of BS 5950:3.1 andEurocode 4 shown in Fig. 2 for 16 and 19 mm diameterstuds.

The sheeting is deemed perpendicular to the steelbeam when the acute angle between the steel sheetingribs and the longitudinal axis of the steel beam exceeds153. Also, the geometry of the steel sheeting mustconform to certain geometric restrictions, in particularb05150 mm and hp480 mm.

It can be ascertained from the previous discussionthat the additional conditions which requirea composite slab to be reinforced against Type 4 failure



are as follows:

d two welded-stud shear connectors are placed ina sheeting pan, irrespective of the length of the slaboutstand; or

d one welded-stud shear connector is placed ina sheeting pan, and the slab outstand is less than600 mm wide measured from the vertical outsideedge of the slab to the adjacent edge of the shearconnector.

Once it is determined that reinforcement is required,the following two alternatives are acceptable.

1. With reference to Fig. 16, the reinforcement mustsatisfy all of the following:

(a) The reinforcement must cross the shearsurface (ie the horizontal plane shown in Fig.16a) and be composed of one or more of thefollowing:

(i) stirrups or ties, which cross perpendicularto the shear surface and encloselongitudinal bars; and

(ii) welded-wire fabric, with the longitudinalwires cranked such that they make anangle of between 30 and 903 with theshear surface.

(b) The maximum transverse spacing ofconsecutive parallel bars or wires which formthe stirrups, ties or fabric must not exceed150 mm measured perpendicular to thelength of the beam (see Fig. 16b).

(c) Reinforcement of nominal yield capacity(Asv fyr ) not less than 20 kN per bar or wiremust be used. At each location, at least twosuch bars or wires must cross the shearsurface every 150 mm width of slab. Thereinforcement must extend into the top andbottom of the slab above and below the shearsurface, respectively, and be adequatelyanchored to develop a stress of at least 0.5 fyr

in the reinforcement at the level of the shearsurface. A width of slab at least equal to400 mm must be reinforced. Thereinforcement must be centred over the steelbeam, except that when the slab outstandwidth is too narrow for this to occur, it mustbe placed as close to the slab edge as concretecover requirements will allow.

2. Any reinforcement detail may be used that hasbeen demonstrated, by adequate test data, toprevent a Type 4 mode of failure.

The second alternative is likely to lead to a moreeconomical solution. The reinforcing componentdescribed in ref. [27] has naturally been deemedsatisfactory in this regard. This new product has nowbeen used successfully on many major buildingprojects in Australia.

Effect of reinforcing component on shearresistance and ductility of welded-studshear connectors

Eight push-out test specimens were designed with thefollowing features, in order to investigate the effectthat the reinforcing component can have on the shearresistance and ductility of welded-stud shearconnectors in the presence of a typical trapezoidalprofiled steel sheeting:

d the specimens were 600 mm wide and constructedwith normal-density concrete, and fcm"37.5 MPa;

d transversely laid trapezoidal steel sheeting wasused with hp"80 mm and b0/hp"1.875;

d 19 mm diameter studs (d"18.9 mm, fu"479 MPa)were welded directly through the sheeting;

d two studs per pan (Nr"2) were placed ina staggered arrangement, centred about a centralpan stiffener with s"80 mm;

d four of the specimens (Group UR) wereu6nr

6einforced below the tops of the studs, while the

other four (Group RC) had the r6einforcing

c6omponent (6 mm diameter transverse and

longitudinal wires, these latter wires shaped to suitthe trapezoidal profile and spaced at 150 mmcentres); and

d the Group UR and RC specimens had studs withfinished heights (h) of 80, 110, 110 and 140 mm(ie specimens 1, 2a, 2b and 3, respectively, notingthat 2a and 2b were repeat specimens).

It can be noted that only the studs in specimensUR-3 and RC-3 met all the geometric requirements ofEurocode 4. Specimens UR-2a,b and RC-2a,b withh"110 mm were also intended to comply, buthp (nominally 76 mm) was measured as 80 mm afterthe studs were placed. Therefore, the studs in thesespecimens did not satisfy h5hp#35 mm, althoughonly by a small margin, noting that this could welloccur in practice.

As expected, all the UR specimens exhibited a ribshearing failure, although in some of these specimensthe horizontal crack only appeared on one side of theslab, and a cone failure occurred on the other side withthe failure surface extending diagonally down andterminating at the sheeting pan. All of these specimensreached their peak load at a slip of less than 1.0 mm,and then failed very suddenly, in a similar way to thatshown in Fig. 5b.

In contrast, none of the RC specimens exhibited a ribshearing failure. The horizontal crack did not appearon the sides of any of the slabs. However, significantbulging of the steel sheeting occurred on thecompressive side of the studs, with the concrete ineffect exhibiting a Type 2 failure around theseconnectors. The cross-wire at the base of each studclosest to the bulging side would clearly have



Fig. 17 Push-out test specimen with reinforcing component: (a) concrete bulging, (b) transverse wire resisting bulging

strengthened this region to some extent (see Fig. 17).The load–slip curves for these tests had the followingcharacteristics:

d the peak load was reached at a slip of less than2 mm;

d complete de-bonding of the sheeting sometimesoccurred at peak load leading to a small drop in

load, which was quickly regained when the slipwas increased; and

d the load progressively dropped away at larger slipsof up to about 10 mm, although the rate of drop-offdiminished with increasing stud height.

The results have been analysed in relation to eqs(1)–(5), and are shown in Fig. 18 with reduction factor,



Fig. 18 Analysis of push-out test results

kt , plotted against stud height, h. The test results havebeen plotted in groups of four data points with lines ofbest fit used to show the trends. The followingexplanation and comments are given with regard tothis figure:

d the values of kt were calculated by dividing thepeak force reached in each stud by the nominalresistance given by eq. (1) with cv"1;

d the highest set of results labelled ‘peak-RC’corresponds to the four specimens tested with thereinforcing component;

d the results ‘6 mm slip-RC’ show the significantextent to which the reinforcing componentmanaged to maintain the shear resistance of thestuds at large slip;

d the peak forces attained in the tests on theunreinforced specimens ‘peak-UR’ wereconsistently less than those in the reinforcedspecimen/s with the same stud height;

d the results ‘6 mm-UR’ show that without thereinforcing component present, there wasabsolutely no shear resistance at large slip;

d the formula given in Eurocode 4 for calculating thereduction factor, kt (ie eq. (3)) is much less accurateoverall than that derived by Lawson (eq. (5)),noting that eq. (3) is particularly conservative at thesmaller stud heights, and unconservative at thelargest stud height for the unreinforced specimens;and

d eq. (5) predicts an almost constant value for kt , andis a reasonably good predictor of the peak forces inthe unreinforced specimens with the higher studs,but does not recognise the loss of strength andductility that results due to rib shearing failure.

Other applications for the reinforcingcomponent (internal beams, continuousbeams and beams with large steel webpenetrations)

The possibility of using the reinforcing component ina broader range of situations than just reinforcing

simply supported composite edge beams is currentlybeing investigated. Although much further research isrequired, initial indications are that the componentcould have other important roles overcoming theweakness caused by introducing profiled steelsheeting into a composite slab, when the slab forms theflange of a composite beam. Some examples are givenas follows.COMPOSITE INTERNAL BEAMS

It was mentioned previously that in AS 2327.1,profiled steel sheeting is not assumed to act astransverse reinforcement for longitudinal shear,irrespective of its orientation. In internal beams, all ofthis reinforcement normally takes the form ofconventional steel bar or fabric placed horizontally inthe cover slab. Tests on beams such as that shown inFig. 14b have confirmed that the reinforcingcomponent can be used instead of conventionalhorizontal reinforcement to prevent Type 2longitudinal shear failure from occurring in internalbeams.

An example by Patrick et al[28] shows that if pairs of19 mm diameter studs are required in every sheetingpan for a profiled steel sheeting with ribs at 200 mmcentres, then the reinforcing component representsa saving of nearly 60% in the mass of transversereinforcement compared with that required byAS 2327.1.

NEGATIVE MOMENT REGIONS OF CONTINUOUS

COMPOSITE BEAMS

Patrick & Dayawansa[29] briefly describe a test ona composite connection subjected to negative bending.Profiled steel sheeting was laid perpendicular to thesteel beams in the test. The slab was 120 mm thick by1200 mm wide, and 19 mm diameter studs wereplaced in pairs in each sheeting pan. Two nominallyidentical specimens were tested, except that oneincluded the reinforcing component. This specimenhad a rotation capacity approximately three times thatof the specimen without the reinforcing component,which exhibited a rib shearing failure.

As a consequence of this finding, the reinforcingcomponent was used to reinforce the composite slab ofa continuous beam in a test by Robinson[30]. Ribshearing failure was not reported.

SIMPLY SUPPORTED COMPOSITE BEAMS WITH LARGE

STEEL WEB PENETRATIONS

Chick et al[31] make mention that a beam test wasplanned in which the reinforcing component would beused to strengthen the composite slab in the region ofa large steel web penetration. In six prior tests in whichthe sheeting ribs were laid perpendicular to the steelbeam, diagonal cracking developed in the slab causinghorizontal delamination above the penetration andsudden failure.



The beam was constructed with the reinforcingcomponent laid in one-half of the beam. This end wastested to failure first with an unreinforced penetrationcut in the web of the steel beam. Although thediagonal crack still formed, the reinforcing componentsignificantly lessened its effect. This wasdemonstrated by testing the other end of thebeam after an identical penetration was cutsymmetrically about mid-span. The maximumbending moment reached at the high-moment endof the penetration with the reinforcing componentwas 10% higher than that reached at the otherpenetration. Moreover, the maximum rotationdeveloped across the stronger penetration due toVierendeel action (ie rotation equals differentialvertical deflection divided by length of penetration)was 2.4 times that at the other end at failure. Therefore,the reinforcing component significantly enhancedboth the strength and ductility of the penetrationregion and thus of the beam.

Conclusions and recommendations

Rib shearing failure has been identified in theliterature as a brittle mode of longitudinal shear failurewhich should be avoided. The new reinforcingcomponent has been developed to prevent this modeof failure from occurring. It has been shown that thisresults in a stronger, much more ductile shearconnection formed between the steel beam andcomposite slab.

It has been explained when the reinforcingcomponent is required in edge beams incorporatingprofiled steel sheeting complying with AS 2327.1.Further research is required to clarify how it could bestbe used with other types of profiled steel sheeting,particularly trapezoidal profiles which are usedextensively in other countries and, as has beendemonstrated herein, for which very significantimprovements in shear connection performancewould be achieved by using the reinforcingcomponent.

Tests have demonstrated that the reinforcingcomponent can also be used successfully to strengthenthe negative moment region of continuous beams, andthe region over large steel web penetrations, when theprofiled steel sheeting is laid transverse to the steelbeam. Significant improvements in ductility have alsoresulted.

Although this paper has focused on rib shearingfailure, there is in general a complex interaction offailure modes. It has been demonstrated that, due tothe presence of the transverse wires, the reinforcingcomponent can also resist other modes of failure, forexample punch-through or Type 2 longitudinal shearfailure.

Acknowledgements

The financial support of One Steel is gratefullyacknowledged. Mr R. Grey of One Steel Reinforcingadvised on the form of final prototypes for thereinforcing component. Dr D. Dayawansa alsocontributed to the development of the product. Theexperimental work was carried out by the technicalstaff at BHP - Melbourne Research Laboratories(closed May 1999) under the supervision of Messrs R.Wilkie and D. Brand.

References and recommended reading

Paper of particular interest have been marked:* Special interest

[1] Oehlers DJ & Bradford MA. Composite steel and concrete structuralmembersefundamental behaviour. New York: Pergamon. 1995.* [2] Hawkins NM & Mitchell D. Seismic response of composite shearconnections. Journal of the Structural Division (ASCE) 1984: 110: 2120d2136.

Early reference to problems associated with rib shearing failure.

* [3] Lloyd RM & Wright HD. Shear connection between composite slabs andsteel beams. Journal of Constructional Steel Research 1990: 15: 255d285.

Proposed theory for predicting occurrence of rib shearing failure.

[4] Grant JA Fisher JW & Slutter RG. Composite beams with formed steeldeck. AISC Engineering Journal 1977: 14(1): 24d43.

[5] Robinson H. Tests on composite beams with cellular deck. Journal of theStructural Division (ASCE) 1967: 93(ST4).

[6] Fisher JW. Design of composite beams with formed metal deck. AISCEngineering Journal 1970: 7(2): 88d96.

[7] Standards Association of Australia. Composite structuresesimplysupported beams. Australian Standard AS 2327.1-1996. Sydney. 1996.

[8] British Standards Institution. Structural use of steelwork in building, Part3. Design in composite construction. Section 3.1, Code of practice for design ofsimple and continuous beams, BS 5950: Part 3: Section 3.1: 1990. London. 1990.

[9] British Standards Institution. Eurocode 4: Design of composite steel andconcrete structures, Part 1.1. General rules and rules for buildings (together withUnited Kingdom National Application Document), DD ENV 1994-1-1: 1994. London.1994.

[10] Johnson RP & Huang D. Resistance to longitudinal shear of compositebeams with profiled steel sheeting. Proceedings of the Institution of Civil EngineersStructures & Buildings 1995: 110: 204d215.* [11] Johnson RP & Anderson D. Designers’ handbook to eurocode 4, Part 1.1:Design of composite steel and concrete structures. London: Thomas Telford ServicesLtd. 1993.

Commentary to Eurocode 4, Part 1.1.

[12] BHP Structural Steel. Composite structures design manualedesignbooklet DB3.1, Design of composite slabs for strength. May 1998.

[13] American Institute of Steel Construction. Load and resistance factordesign specification for structural steel buildings. December 1, 1993.* [14] Lawson RM. Shear connection in composite beamseinfluence of steeldeck shape. Proceedings of an Engineering Foundation Conference, CompositeConstruction in Steel and Concrete III, ASCE. 1997. 312d324.

Model for cone failure of wide concrete ribs.

* [15] Jayas BS & Hosain MU. Behaviour of headed studs in hollow compositebeams. Structural Engineering Research Report No. 30, University of Saskatchewan,June, 1987.

[16] Mottram JT & Johnson RP. Push tests on studs welded through profiledsteel sheeting. The Structural Engineer 1990: 68(10): 187d193.

[17] Johnson RP & Yuan H. Shear resistance of stud connectors with profiledsheeting. Proceedings of an Engineering Foundation Conference, CompositeConstruction in Steel and Concrete III, ASCE. 1997: 555d560.

[18] Standards Association of Australia. Composite structuresesimplysupported beams. Australian Standard AS 2327.1-1980, Sydney. 1980.



[19] Robinson H. Multiple stud shear connections in deep ribbed metal deck.Canadian Journal of Civil Engineering 1988: 15: 553d569.

[20] Easterling WS, Gibbings DR & Murray TM. Strength of shear studs insteel deck on composite beams and joists. AISC Engineering Journal 1993: 30(2):44d55.

[21] Hicks SJ & McConnel RE. The shear resistance of headed studs used withprofiled steel sheeting. Proceedings of an Engineering Foundation Conference,Composite Construction in Steel and Concrete III, ASCE. 1997: 325d338.

[22] Kemp AR & Trinchero PE. Horizontal shear failures around connectorsused with steel decking. Proceedings of an Engineering Foundation Conference,Composite Construction in Steel and Concrete III, ASCE. 1997: 104d118.

[23] Patrick M, Dayawansa PH, Eadie I, Watson KB & van der Kreek N.Australian composite structures standard AS 2327, Part 1: simply-supported beams.AISC Steel Construction 1995: 29(4): 2d40.

[24] Roik K & Lungershausen H. Shear resistance of headed stud shearconnectors in concrete slabs with profiled steel sheeting. Stahlbau 1989: 58(9):269d273.

[25] Patrick M, Tse D & Wilkie R. Combined shear-tension testing of the HiltiHVB Shear Connector. Structural Steel. PSSC ’95 4th Pacific Structural Steel

Conference: 3: Steel-Concrete Composite Structures. Amsterdam: Elsevier ScienceLtd. 1995: 203d210.

[26] Patrick M, Dayawansa PH, Wilkie R & Watson KB. Partial shearconnection strength design of simply-supported composite beamsedraft revision ofAS 2327, Part 1. AISC Steel Construction 1994: 28(1): 2d32.

[27] BHP Reinforcing Products. New BHP DECKMESH. March 1996.[28] Patrick M, Grey R & Marsden W. Reinforcing against longitudinal shear

failure of composite edge beams. Concrete ’97 Conference. Cement & ConcreteAssociation of Australia. 1997: 253d260.

[29] Patrick M & Dayawansa D. Design of continuous composite beams forbending strength. Proceedings of Australasian Structural Engineering Conference(ASEC-98). Auckland. September 1998.

[30] Robertson BR. Composite connections for semi-continuous compositebeams, Undergraduate thesis. Dept Civil, Mining and Environmental Engng. Universityof Wollongong. 1997.

[31] Chick C, Dayawansa D & Patrick M. Strength design of simply-supported composite beams with large steel web penetrations. Proceedings ofAustralasian Structural Engineering Conference (ASEC-98). Auckland. September1998.

M PatrickSchool of Civic Engineering and Environment,University of Western Sydney,Kingswood, NSW 2747,Australia



Documents

Experimental investigation and design of longitudinal shear reinforcement in composite edge beams