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Punching ShearReinforcementfor the Construction Industry
CI/SfB (29) Et6
July 2009
22
This brochure is printed on paper produced from 80%recycled post-consumer fibre and 20% virgin pulp which issourced from responsibly managed and sustainable forests(FSC certified). The printing inks and sealant are vegetable-based making the document fully recyclable.
Ancon designs and manufactures high integrity steel products for
the construction industry. Through continuous programmes of
new product development, inward investment and employee
advancement, the company is committed to maintaining the
highest level of customer service within a dynamic and
challenging industry.
Masonry Support Systems
Masonry Reinforcement
Windposts and Lintels
Wall Ties and Restraint Fixings
Channel and Bolt Fixings
Tension Systems
Stainless Steel Fabrications
Flooring and Formed Sections
Shear Load Connectors
Reinforcing Bar Couplers
Reinforcement Continuity Systems
Punching Shear Reinforcement
Insulated Balcony Connectors
Refractory Fixings
3
Used within a slab to provide additionalreinforcement around columns, Ancon Shearfixis the ideal solution to the design andconstruction problems associated withpunching shear. The system consists of double-headed studs welded to flat rails, positionedaround the column head or base.
Punching Shear 4
The Shearfix Solution 4
Comparison with Shear Links 4
Sizes and Configurations 5
Product Identification 5
Design Program 6-7
System Design to BS8110 8
Design Sheet 9
Typical Rail Arrangements 10
Installation Procedure 10Applications 11
Other Ancon Products 11
ISO 9001: 2008FM 12226
ISO 14001: 2004EMS 505377
Shearfix Punching Shear Reinforcement
4
PUNCHING SHEARThe weight of a slab supported on a columninduces shear stresses in the slab. Thesestresses, if sufficient and where additionalreinforcement has not been provided, wouldresult in the column ‘punching’ through theslab. This punching shear is similarly inducedin the footing on which the column bears.
THE SHEARFIX SOLUTIONUsed within a slab to provide additionalreinforcement around columns, Ancon Shearfixis the ideal solution to the design andconstruction problems associated withpunching shear.
The system consists of double-headed studswelded to flat rails, positioned around thecolumn head or base. The shear load fromthe slab is transferred through the studs intothe column.
Shearfix is suitable for all column shapes andis easy to install either ‘top down’ or ‘bottomup’, depending on user preference (page 10).
Punching Failure
Comparison with Shear LinksAncon Shearfix offers many advantagesover loose shear links. Links can be time-consuming to both design and install.A Shearfix system is easily detailed withAncon’s free calculation program whichgenerates a layout drawing for inclusion in thebuilding plans and, rather than being installedindividually, these studs are supplied to sitewelded to rails at the appropriate spacing.
When comparing links with studs, researchhas shown that any additional material costsincurred when purchasing a prefabricated studsystem, such as Shearfix, are generally faroutweighed by the savings from a significantlyreduced fixing time; these systems being up toten times quicker to install (source: BritishCement Association: Prefabricated punchingshear reinforcement for reinforced concrete flatslabs. BCA, Camberley, 2001).Although punching shear can be relieved by
localised thickening of the concrete withdownstand beams and enlarged columnheads, the construction of flat slabs offersmany advantages. A consistent head spacecan reduce the overall height of a building andprovide significant time and material savings.
Corner column using anorthogonal rail arrangement
‘Top down’ installation. A row of studs is passed through the reinforcement grid as aunit and the rail is tied to the main reinforcement
5
Sizes and ConfigurationsThe Ancon Shearfix system comprisesdouble-headed studs welded to flat rails. It ismanufactured to suit the specific requirementsof each application. The quantity of eachcomponent, the dimensions and spacings,and the layout pattern around the column aredetermined by calculation. Ancon providesfree software to determine the optimumsystem design (see pages 6-7).
Studs are manufactured in six diameters (10,12, 14, 16, 20 and 24mm) from high strengthsteel bar. The heads are hot forged to threetimes the diameter of the bar. Studs aremanufactured in virtually any length to suit thedepth of slab, but are normally formed inincrements of 10mm within the 100-500mmrange. The bar used in this system has acharacteristic yield strength of 500N/mm2.
The studs are welded to the rail at the centresdetermined by Ancon’s software or a designcalculation. The rail performs no structuralfunction but ensures stud alignment andpositioning within the slab.
Shearfix rails are manufactured from strips ofsteel, 16mm wide. The gap between the stripsallows for the passage of concrete duringpouring and also enables the rail to be nailedthrough spacers to formwork when fixed‘bottom up’ i.e. prior to all other reinforcement.
Double-headed Stud 10, 12, 14,16, 20 and 24mm diameters
Rail
0.5d 0.75d 0.75d 0.5d
Studdiameter
Stud
leng
th
Ove
rall d
epth
Note: d=effective slab thickness
Tel: +44 (0) 114 275 5224 Web: www.ancon.co.uk
0.5d
120mm
0.75d
180mm
0.75d
180mm
0.5d
120mm
Studdiameter12mm
Stud
leng
th
230m
m le
ngth
AS12-3-230-600
Product IdentificationEach rail of studs carries the following identification:
Shearfix Code and Stud Diameter - Number of Studs - Stud Length - Rail Length
Column/Grid Reference
Floor Level
e.g. AS12-3-230-600
K15
Level 2
All dimensions are in millimetres.
PROJECT MANAGEMENTPlease contact Ancon if you would like helpin creating a Shearfix schedule and aprogramme for delivery to suit progress onsite. If advised at the time of ordering,pallets can be packed in priority order e.gby pour number.
Ancon’s ‘Products for Structural Concrete’division offers a dedicated service to theconcrete sector. Contact the team on +44 (0) 114 275 5224 with your Shearfixenquiry.
Shearfix Punching Shear Reinforcement
6
DESIGN PROGRAMShearfix is designed to suit the specificrequirements of each application. Anconprovides a free design program to simplify thespecification and ordering of a Shearfixsystem.
This easy-to-use program allows the optimumsystem design to be determined andgenerates a printable data sheet and a DXF fileof the specified layout. Solutions can becreated for all column sizes, shapes andlocations including columns offset from edgesand corners.
The program allows analysis to BS 8110-1,DIN 1045-1 and AS 3600. For a Eurocode 2version please contact Ancon.
Users can design a radial or an orthogonal raillayout. This feature, which is unique to theAncon program, allows the most economicaldesign (fewest number of studs) to beachieved for each application.
Where there are openings close to the column,a section of the slab will be ineffective andperimeters will need to be reduced; the Ancondesign program allows these reductions to beapplied to each perimeter.
The program requires the followinginformation:
• Column shape(circular, rectangular or ‘L’ shape)
• Column dimensions
• Column location (interior, edge, externalcorner, re-entrant corner)
• Dimension to concrete edge(for offset corner and edge columns)
• Slab thickness
• Concrete grade
• Reinforcement size and spacing
• Cover to reinforcement
• Shear load
• Applied moments
This free program can be downloadedfrom www.ancon.co.uk, emailed onrequest or supplied on CD. Contact Anconon +44 (0) 114 275 5224 for your copy.
A hard copy of the calculation method toBS 8110 is available on request.
Screen shot of a circular column offset from one edge, with a radial stud layout
The datasheet generated
The DXF file generated
7
Tel: +44 (0) 114 275 5224 Web: www.ancon.co.uk
Screen shot of a rectangular column, offset from a re-entrant corner, with an orthogonal rail layout
The datasheet generated
The DXF file generated
8
Shearfix Punching Shear Reinforcement
DESIGN INFORMATION:BS 8110-1:1997The shear stress is checked at a perimeter1.5d (d = effective slab thickness) from theface of the column (u0), further checks arecarried out at successive intervals of 0.75d (u1,u2 etc) until a perimeter is reached which doesnot require shear reinforcement (un).
The first stud is positioned 0.5d from the faceof the column, with the spacing betweenindividual studs taken as 0.75d with amaximum limit of 500mm. The maximumspacing between parallel rails is 1.5d.
When using the Ancon design program acheck is carried out for over-reinforcement; ifthis check fails, a warning message states thatfailure due to punching shear is possible andan increase in slab thickness will be required.
Two layouts are available, radial and orthogonal.
Radial LayoutRails are positioned on the two main axes toall available column faces with diagonal rails atthe corners; all perimeters have radiusedcorners, circular columns have circularperimeters. The spacing between theoutermost studs on the diagonal rails is kept toa maximum of 3d.
Orthogonal LayoutRails are positioned on the main axes to allavailable column faces, additional rails arepositioned in line with one of the main axesand set at 0.75d centres in line with the studpositions. All perimeters will be rectangular.
Effect of Slab PenetrationsWhere there are openings in the slab within 6dof the column (clause 3.7.7.7), a section of theslab will be ineffective and perimeter lengthswill need to be reduced. The Ancon designprogram allows reductions to be applied toeach perimeter as appropriate.
u0
u1
u2
un
1.5d0.75d0.75d
Ineffective shearperimeter
0.75d 0.75d
u0
u1
u2
un
1.5d0.75d0.75d 0.75d0.5d 0.75d
0.5d
Opening
Any opening within 6d of columnface must be considered
Radial Layout
Orthogonal Layout
TECHNICAL SUPPORTIn addition to the Shearfix design program shown on pages 6 and 7, Ancon’sTechnical Services Team has created a fax-back form which allows engineersto summarise the critical details of their project and request technical assistancewith a Shearfix design. This form is shown on page 9.
9
CONTACT DETAILS
Contact name. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Company . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Office Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Email . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DESIGN CONDITIONS
Floor Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Column Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Concrete Grade (N/mm2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Total Shear Load Vt (kN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Moment Mx (kNm) - If known . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Moment My (kNm) - If known . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Slab Thickness (mm). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Critical Tension Reinforcement (d1) Ø mm @ mm centres
Critical Tension Reinforcement (d2) Ø mm @ mm centres
Cover (mm). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SKETCH OF COLUMN & LOCATIONinclude edges, voids and other features which may affect the design
PROJECT DETAILS
Project Name . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Project Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
EXAMPLE SKETCH
Faxback to +44 (0) 114 276 8543 or email: [email protected] Building Products, President Way, President Park, Sheffield S4 7UR, United KingdomTel: +44 (0) 114 275 5224, Web: www.ancon.co.uk
Design Sheet - Punching Shear Reinforcement
Please provide: Contact details; project details; design conditions; sketch of column & location
Note: The solution provided will be based on the design method to BS8110 unless requested otherwise.
. . . . . . . .
. . . . . . . .
Please photocopy this page. A continuation sheet for other columns with the same design conditions is available at www.ancon.co.uk
10
Shearfix Punching Shear Reinforcement
INSTALLATION PROCEDURE
Ancon Shearfix is quick and simple to install.It can be fitted either ‘top down’ (after all otherreinforcement) or ‘bottom up’ (prior to otherreinforcement).
‘Top down’ Fixing
• Fix all main reinforcement in position
• Place Shearfix rails around the column tothe layout detailed on job drawings bypassing the studs through thereinforcement grid and resting the carrierrails on the top layer of reinforcement
• Tie rails with wire to main reinforcementand pour concrete
‘Bottom up’ Fixing
• Tie rails with wire to concrete spacers inorder to maintain cover
• Place rail and spacer units around thecolumn to the layout detailed on jobdrawings
• Hammer nails through gap in rails to fix thesystem to formwork
• Fix main reinforcement in position and pourconcrete
‘Top down’ fixing
‘Bottom up’ fixing
TYPICAL RAIL ARRANGEMENTSShearfix is suitable for all column shapes andlocations. Some typical arrangements areshown here.
Orthogonal Layouts
Radial Layouts
APPLICATIONS OTHER ANCON PRODUCTS
Reinforcing Bar CouplersThe use of reinforcing bar couplers can providesignificant advantages over lapped joints.Design and construction of the concrete canbe simplified and the amount of reinforcementrequired can be reduced. The Ancon rangeincludes parallel threaded, tapered threadedand mechanically bolted couplers.
Reinforcement Continuity SystemsReinforcement Continuity Systems are anincreasingly popular means of maintainingcontinuity of reinforcement at constructionjoints in concrete. Ancon Eazistrip is approvedby UK CARES and consists of pre-bent barshoused within a galvanised steel casing. Onceinstalled, the protective cover is removed andthe bars are straightened.
Insulated Balcony ConnectionsAncon Isolan connectors join external concretebalconies to internal concrete floor slabs. Usedto minimise cold bridging, they providecontinuity to the thermal insulation. Standardsystems, comprising rigid CFC-free polystyreneinsulation and duplex stainless steel shearreinforcement, suit most depths of cantileverand simply supported balconies. Conventionalreinforcing bars are used to provide the tensionand compression reinforcement.
Shear Load ConnectorsAncon DSD and ESD Shear Load Connectorsare used to transfer shear across expansionand contraction joints in concrete. They aremore effective at transferring load and allowingmovement to take place than standard dowels,and can be used to eliminate double columnsat structural movement joints in buildings.
Channel and Bolt FixingsAncon offers a wide range of channels andbolts in order to fix stainless steel masonrysupport, restraints and windposts to structuralframes. Cast-in channels and expansion boltsare used for fixing to the edges of concretefloors and beams.
Special Fabrications
Ancon designs and manufactures high integrity
steel components for a wide range of
industries including Civil Engineering, Building,
Infrastructure, Water Treatment, Nuclear and
Mining. Projects are supplied worldwide and
range from small-scale residential
developments to major infrastructure projects.
11
Tel: +44 (0) 114 275 5224 Web: www.ancon.co.uk
Markeaton Street, Derby, UK
Phot
o: U
nive
rsity
of D
erby
Kings Dock Mill, Liverpool, UK
Victoria Point, Melbourne, Australia
© Ancon Building Products 2007
The construction applications and details provided in this literatureare indicative only. In every case, project working details should beentrusted to appropriately qualified and experienced persons.
Whilst every care has been exercised in the preparation of thisdocument to ensure that any advice, recommendations orinformation is accurate, no liability or responsibility of any kind isaccepted in respect of Ancon Building Products.
With a policy of continuous product development Ancon BuildingProducts reserves the right to modify product design andspecification without due notice.
These products are available from:
Ancon Building ProductsPresident Way, President ParkSheffield S4 7URUnited KingdomTel: +44 (0) 114 275 5224Fax: +44 (0) 114 276 8543Email: [email protected]: www.ancon.co.uk
Ancon (Middle East) FZEPO Box 17225Jebel AliDubaiUnited Arab EmiratesTel: +971 (0) 4 883 4346Fax: +971 (0) 4 883 4347Email: [email protected]: www.ancon.ae
Ancon Building Products114 Kurrajong AvenueMount DruittSydneyNSW 2770AustraliaTel: +61 (0) 2 8808 1111Fax: +61 (0) 2 9675 3390Email: [email protected]: www.anconbp.com.au
Ancon (Schweiz) AGGewerbezone Widalmi 103216 Ried bei KerzersSwitzerlandTel: +41 (0) 31 750 3030Fax: +41 (0) 31 750 3033 Email: [email protected]: www.ancon.ch
Ancon Building Products GesmbHGerspergasse 9/3 Top 1A-1210 ViennaAustriaTel: +43 (0) 1 259 58 62-0Fax: +43 (0) 1 259 58 62-40Email: [email protected]: www.ancon.at
Ancon GmbHBartholomäusstrasse 2690489 NurembergGermanyTel: +49 (0) 911 955 1234 0Fax: +49 (0) 911 955 1234 9Email: [email protected]: www.anconbp.de
ISO 9001: 2008FM 12226
ISO 14001: 2004EMS 505377
This brochure is printed on paper produced from 80%recycled post-consumer fibre and 20% virgin pulp which issourced from responsibly managed and sustainable forests(FSC certified). The printing inks and sealant are vegetable-based making the document fully recyclable.
