Bison Hollow Core Floors

H O L L O W C O R E F L O O R SS P E E D A N D S T R E N G T H

C O N T E N T S

INTRODUCTION

PRECAST CONCRETE FLOORSTH E AD VA N TA G E S

BISON HOLLOW CORE FLOORS

BEARINGS

FALSE CEILINGS AND SOFFITFIXINGS

BISON HOLLOW COMPOSITEFLOORS

BISON SOLID COMPOSITEFLOORS

BISON SOLID COMPOSITEFLOORS CO N S T R U C T I O N DE TA I L S

SOUND INSULATIONWITH BISON HOLLOW CORE SLABS

BISON PRECAST FLOORINGSPECIFICATION

QUALITY ASSURANCE

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I N T R O D U C T I O N

Bison is the largest producer of precast concrete

floors in the United Kingdom.

The company has been a leader in the design and

manufacture of structural products since 1919.

There are five Bison factories throughout the

United Kingdom strategically situated to provide

a comprehensive service to our customers.

This brochure describes the extensive range of

precast flooring available to the specifier.

Other products pioneered by Bison and for which

they hold a market leading position include house

floors for use both at ground floor and intermediate

levels and precast prestressed staircases produced by

a patented method which provides a product of

excellent quality at moderate cost.

In the field of structures too, Bison is a market

leader producing precast concrete, steel and

composite structures for use in retail, industrial,

commercial buildings and car parks as well as in

housing, educational and government projects.

Brochures on other Bison products and services for

the construction industry are listed on the back

cover of this brochure.

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Speed of ErectionTime consuming activities such as propping,shuttering and concrete pouring are virtuallyeliminated.

Diaphragm ActionPrecast floor slabs are structurally grouted to providea floor with full diaphragm action as required inmost multi–storey frameworks.

Shelf Angle BearingSlab ends can be notched during manufacture tofacilitate a bearing within the depth of a mainsupporting steel. This minimises storey height, withsubstantial cost benefits arising from reducedcladding costs, lower internal fitting costs etc.

No ProppingPropping is generally not required with hollow corefloors.Compare this with the large amount ofpropping required with insitu and semi-insitu floorsystems.

Fire ResistanceStandard precast floors can be supplied with a fireresistance of up to 2 hours.Periods in excess of thiscan be provided with modified sections if required.

Minimum Insitu ConcreteUsing a precast floor, a large volume of work iscarried out off site and saves what can be complexand time consuming site operation subject to thevagaries of the climate.

Immediate Unpropped Working PlatformOnce a precast floor is erected, it is immediatelyavailable as a working platform. Steel deck systems by comparison can presentproblems in achieving level surfaces whilst concreteis poured and in providing access whilst in thepropped condition.

P R E C A S T C O N C R E T E F L O O R S T H E A D VA N T A G E S

Preformed Site ServicesPrecast floors can be provided with factory formedservice holes thus avoiding laborious setting outand shuttering on site.

Extra Long SpansFactory made prestressed units offer the maximumdesign advantages of achieving long span units forgiven depths. This avoids the need for intermediatesupports and provides an economically light solutionthroughout the entire structure. The Bison long span450 mm deep unit can span in excess of 16 metres.

Finished SoffitsPrecast floors are manufactured on high qualitysteel beds and are suitable in appropriate cases fordirect decoration.

Flexibility of Design ApproachPrecast floors are available with a variety offactory formed notches, slots and reinforcementarrangements which offer various design approaches.

Elimination of Edge ShutteringEdge shuttering to any building is inevitably adifficult and often dangerous operation. This can betotally avoided by using a precast floor.

Structural EfficiencyA hollow core slab offers the ideal structural sectionby reducing the deadweight whilst providing themaximum structural efficiency within the slab depth.

Factory Produced to Rigorous Quality StandardsBecause precast floors are factory produced, theyare manufactured in an environment which is morereadily controlled than a building site.Quality control systems are properly implementedand are independently examined on a regular basisunder the British Standards Institution QualityAssurance Scheme.

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Spans indicated below allow for characteristic service load (live load) plus self weight plus 1.5 kN / m2 for finishes

Characteristic service loads kN / m2

Effective span in metres0.75 1.5 2.0 2.5 3.0 4.0 5.0 7.5 10.0 15.0

Overallstructuraldepth mm

Availablefire period

Self WtkN / m2

100 1 Hour or 2* Hour 2.40 5.0 5.0 5.0 5.0 5.0 4.9 4.6 4.0 3.6 3.1

200 2 Hour 2.85 10.0 10.0 10.0 9.4 9.3 8.8 8.3 7.3 6.6 5.6

300 2 Hour 3.95 15.0 14.7 14.2 13.8 13.3 12.6 12.0 10.8 9.9 8.6

400 2 Hour 4.85 18.0 17.3 16.8 16.3 15.8 15.1 14.4 13.0 12.0 10.5

150 1 Hour or 2* Hour 2.40 7.5 7.5 7.5 7.5 7.2 6.7 6.3 5.6 5.0 4.3

250 2 Hour 3.30 12.4 11.7 11.3 10.8 10.5 10.1 9.6 8.5 7.7 6.6

350 2 Hour 4.45 16.9 16.2 15.7 15.2 14.8 14.0 13.4 12.0 11.0 9.6

450 2 Hour 5.35 19.4 18.6 18.1 17.5 17.1 16.3 15.6 14.2 13.1 11.5

B I S O N H O L L O W C O R E F L O O R S

LOAD / SPAN TABLE

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Widely used in masonry, steel and concrete structures for domestic, commercial and industrial buildings.The most economic flooring solution for the widest variety of situations, providing the maximum benefitsof speed of construction.

The table is given as a guide only. When using maximum spans, consideration must be given to the effect of camberand deflection on partitions or finishes. Further advice is available on request. * 35mm screed required.

UNIT PROFILES

1200 mm Nominal width



100 mm Thick

150 mm Thick200 mm250 mm

300 mm Thick350 mm400 mm450 mm

B E A R I N G S

25 mm clearance is required to allow unit to be dropped intoposition past the flange of the supporting U.B.

25 mmclearance

Where required by Building Regulations for sound insulation.

Nominal bearing 75Minimum bearing 50

Finishes

Wall thickness t > 190

Nominal bearing t / 2 - 10 mm

Finishes

Continuous wet mortar by builder totake up camber

BEARINGS ON SHELF ANGLES

BEARINGS ON MASONRY

Finishes

Structural concrete infill

SIDE BEARING

Projection of anglebeyond extremity offlange 50 mm.Greater where U.C.sections are used

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t

Flange widtht < 150 (Min.140 mm)

The recommendations for bearings of precast units are set out in Clause 5.2.3 of B.S. 8110:1997. These vary according to the type

of floor construction and the type of support material and building tolerances. In general nominal bearings of 100 mm on masonry

or 75 mm on steelwork are recommended but may be reduced dependent upon circumstances and subject to the above clause.

NARROW BEARING ON STEELWORK

TRIMMING OPENINGSEND SLOTS IN UNITS

Finishes

( NB. In order to satisfy the tolerances in this situation, thisdetail is only recommended where a full bearing is available at the other end of the slab)

Tie reinforcement at400 c/c in joints andtroughs provided in1200 wide units

M.S.Trimmer.Fire protection, where necessary by General Contractor

Slots may be provided in slab ends for the purpose of tyinginto the structure for nominal continuity

NARROW WALL BEARING

Wall thickness t < 190 (Min. 140 mm)

Nominal bearing t / 2 - 10 mm

Nominal bearing t / 2 - 10 mm(Min. 65 mm)

Finishes

Tie reinforcement at400 c/c in joints andtroughs provided in1200 wide units

B E A R I N G S

Structural concrete infillStructural concrete infill

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tt

F A L S E C E I L I N G S A N D S O F F I T F I X I N G S

A wide variety of methods to suspend ceilings and services are available.Some alternative methods are shown below.

Shot firing is not recommended. Various site-drilled anchors are available and, used in accordancewith the manufacturers instructions, are a simple and economic fixing method.

COUNTER BATTENS FIXED DIRECT TO SLAB SOFFIT

CLIPS OR HANGERS FIXED IN SLAB JOINTS

TYPICAL CEILING HANGERS

DETAIL OF CEILING HANGERIN SLAB JOINT

TYPE ‘WL’ WIRE CEILING CLIPIN SLAB JOINT

Type ‘A’ hangers

TYPE ‘ A ’ TYPE ‘ B ’ TYPE ‘ C ’20g M.S. Galvanised or Sheradized

Bend over shank of hanger

Joint to be grouted

Wire loops bent under battenand nailed upwards

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Type ‘B’ hanger

B I S O N H O L L O W C O M P O S I T E F L O O R S

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Effective span in metres0.75 1.5 2.0 2.5 3.0 4.0 5.0 10.0 15.0


Unitdepth

Available fire period

Self WtkN / m2

200 150 1 Hour or 2 Hour 3.60 8.2 8.2 8.2 8.2 8.0 7.6 7.3 6.0 5.2

300 250 2 Hour 4.45 12.1 11.6 11.2 11.0 10.7 10.2 9.8 8.1 7.0

425 350 2 Hour 6.20 15.7 15.2 14.9 14.6 14.3 13.8 13.3 11.6 10.3

525 450 2 Hour 7.10 18.0 17.5 17.1 16.8 16.5 15.9 15.4 13.4 12.1

250 200 1 Hour or 2 Hour 4.00 10.7 10.3 10.0 9.7 9.5 9.0 8.7 7.2 6.2

375 300 2 Hour 5.75 14.3 13.8 13.5 13.2 13.0 12.5 12.1 10.4 9.3

475 400 2 Hour 6.60 16.8 16.2 15.9 15.6 15.3 14.7 14.2 12.4 11.1

A combination of the Bison Hollow Core Slab with a structural concrete topping. This type of floor givesthe benefit of an increased structural performance with an enhanced lateral load distribution wherenecessary for heavy point loads. The floor may be designed in the unpropped or partially propped conditionto suit particular requirements. This floor is particularly suitable for industrial buildings, high buildings, carparks or other structures where additional longitudinal and transverse tying is required.

LOAD / SPAN TABLE

The above data is based upon 50 or 75 mm structural topping of C30 concrete which should be regarded as a minimum.Other topping depths may be recommended in some circumstances. Design data for alternative combinations areavailable from Bison Design Offices. Topping reinforcement, daywork and movement joints should be considered inrelation to the overall structural concept of the building.

COMPOSITE PROFILES


50 or 75 mm

150 mm Thick200 mm250 mm

Composite depth200 mm250 mm300 mm

75 mmComposite depth375 mm425 mm475 mm525 mm 300 mm Thick

350 mm400 mm450 mm


*Minimum structuraldepth 50mm at centreof span. Overallthickness at bearingmust take account ofthe camber of the slab.

200 4.71 3.75 3.75 3.75 3.75 3.75 3.75 3.75 3.66 3.47

175 4.12 3.75 3.75 3.75 3.75 3.75 3.75 3.75 3.69 3.44

150 3.54 3.75 3.75 3.75 3.75 3.75 3.75 3.75 3.63 3.32

125 2.95 3.75 3.75 3.75 3.75 3.75 3.75 3.75 3.44 3.07

200 4.71 7.50 7.50 7.50 7.50 7.50 7.34 6.98 5.74 4.84

175 4.12 7.50 7.50 7.42 7.18 6.97 6.60 6.28 5.18 4.18

150 3.54 7.29 6.86 6.61 6.38 6.18 5.83 5.53 4.52 3.64

125 2.95 6.42 6.00 5.76 5.55 5.36 5.03 4.60 3.74 2.88

1 Hour Fire R

esistance

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B I S O N S O L I D C O M P O S I T E F L O O R S

LOAD / SPAN TABLE

Combines the advantages of a precast, prestressed element acting compositely with an insitu concretestructural topping to form a solid slab. The prestressed element, whilst eliminating the need for conventionalshuttering, provides a structural performance far superior to normally reinforced concrete. This provides theengineer with the scope to incorporate all of the details normally associated with insitu design, such as thetying in of balconies, trimming of openings, maximum load distribution and minimum structural depth.



Effective span in metres0.75 1.5 2.0 2.5 3.0 4.0 5.0 10.0 15.0


Unitdepthmm

Self WtkN / m2

150 3.54 7.34 6.90 6.65 6.43 6.23 5.87 5.57 4.52 3.60

250 5.89 10.00 9.85 9.57 9.30 9.05 8.61 8.22 6.86 5.92

150 3.54 5.00 5.00 5.00 5.00 5.00 5.00 5.00 4.34 3.86

200 4.71 8.88 8.44 8.18 7.94 7.72 7.33 7.00 5.82 4.84

300 7.07 10.00 10.00 10.00 10.00 9.83 9.39 9.01 7.61 6.71

250 5.89 5.00 5.00 5.00 5.00 5.00 4.95 4.89 4.61 4.38

150 3.54 7.34 6.90 6.65 6.43 6.23 5.87 5.57 4.12 3.22

250 5.89 10.00 9.77 9.48 9.21 8.96 8.52 8.14 6.79 5.73

200 4.71 5.00 5.00 5.00 5.00 5.00 5.00 5.00 4.65 4.30

300 7.07 4.77 4.74 4.72 4.70 4.68 4.64 4.61 4.44 4.29

200 4.71 8.88 8.44 8.18 7.94 7.72 7.33 7.00 5.72 4.53

150 3.54 5.00 5.00 5.00 5.00 5.00 4.91 4.73 4.06 3.62

250 5.89 4.83 4.78 4.75 4.72 4.69 4.63 4.58 4.32 4.11

300 7.07 10.00 10.00 10.00 10.00 9.81 9.38 8.99 7.60 6.70

200 4.71 5.00 5.00 5.00 5.00 4.99 4.88 4.78 4.36 4.03

300 7.07 4.46 4.44 4.42 4.40 4.38 4.35 4.32 4.16 4.02

*Propped

orUnpropped

100

100

1 Hour Fire R

esistance2 H

our Fire Resistance

P

P

P

U/P

U/P

U/P

*Enhancement of the stated fire period may be achieved by applied soffit finishes.

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Solid composite construction utilises the advantages of a prestressed precast element acting compositelywith an insitu structural topping, combining the benefits of precast and insitu construction.These benefits arereduced construction depths, speed of erection, elimination of shuttering, minimal propping, fire resistance,and the flexibility of architectural and engineering design.

COMPOSITE PROFILE

O / A Depth

75 or 100 mmDeep

SIMPLE BEARING ON TOPFLANGE OF STEELWORK

SLAB COMPOSITE WITHSUPPORTING BEAM

B I S O N S O L I D C O M P O S I T E F L O O R SC O N S T R U C T I O N D E T A I L S

40 mmMin. bearing

40 mmMin. bearing

Flange reinforcement and shear studs as required by steelwork design

Nominal support reinforcement and/or daywork jointsdetermined by general layout and site operation

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D

B I S O N S O L I D C O M P O S I T E F L O O R SC O N S T R U C T I O N D E T A I L S

SHELF ANGLE BEARING CANTILEVER CONSTRUCTION

Nominal 50 mmbearing forprecast elements

Nominal 50 mm bearingfor precast elements

Solid composite floors may be placed on insitu beamdownstands or supported on shutters before pouring site concrete

Beam depths and widths to suit specific requirements

INSITU CONSTRUCTION

Nominal 50 mm bearing

Minimum 25 mm cover to top of steel beam flange

Minimum 50 mmclearance

Precast balconyelement

Insitu structural topping on precast element

Temporary propping during construction

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S O U N D I N S U L A T I O NW I T H B I S O N H O L L O W C O R E S L A B S

The Building Regulations (Approved Document 1992 ) set out the sound insulation requirements both forairborne and impact sound for a floor separating dwellings. When using precast concrete units, two alternativetypes of construction meet the requirements. They are as follows:

FLOOR TYPE 1

FLOOR TYPE 2

Soft covering of resilient material

Floor Base comprising structural slab togetherwith any directly bonded screed plus ceilingfinish. Mass < 365 kg/m2

CONCRETE BASE WITH SOFT COVERING

Examples of floors complying with type 2 requirements are as follows:

SCREED ( 35 mm Sand / Cement ) 65 kg/m2 SCREED ( 60 mm Sand / Cement ) 115 kg/m2 SCREED ( 30 mm Sand / Cement ) 60 kg/m2

CONCRETE BASE WITH FLOATING LAYERFloating layer ( timber or screed )Resilient layer

Floor Base comprising structural slab togetherwith any directly bonded screed plus ceilingfinish. Mass < 300 kg/m2

Floating layer on resilient layer SCREED 50 kg/m2

The Bison sound slab has been specially developed to provide an economic and structurally efficient meansof satisfying the requirements of sound insulation.

1200 mm

150 mm

Examples of compliant construction using Bison profiles are as follows:

THE BISON SOUND SLAB ( TYPE RS )

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200 mm Standard Bison slab 300 kg/m2 150 mm Standard Bison slab 250 kg/m2 150 mm Bison sound slab 307 kg/m2

200 mm Standard Bison slab 300 kg/m2 150 mm Standard Bison slab 250 kg/m2 150 mm Bison sound slab 307 kg/m2



Effective span in metres0.75 1.5 2.0 2.5 3.0 4.0 5.0 7.5 10.0 15.0


Available fire period

Self WtkN / m2

150 2 Hours 3.02 7.5 7.5 7.5 7.3 7.1 6.6 6.2 5.5 5.0 4.3

Building Regulation requirement is:

Building Regulation requirement is:

Floating layer on resilient layer

B I S O N P R E C A S T F L O O R I N GS P E C I F I C A T I O N

MANUFACTUREBison Floors are manufactured by the long line prestressed method using slip form or extrusiontechniques. The units are cast on heated steel beds within an enclosed factory environment.

The materials used in the manufacture of BisonFloors comply with the relevant British Standardfor that material.

An air entraining agent complying withB.S.5075 Pt.2:1982 is included in the concretemix to improve workability.

Reinforcement is generally 5mm diameter high tensile wire or12.5mm diameter strandcomplying with the requirements of B.S.5896:1980.

Bison units are sawn to length on themanufacturing bed and are supplied as standardwith plain sawn ends with open cores.

DIMENSIONSBison Units are manufactured in nominal sizes as follows :Standard nominal width of all units is 1200mm.

Solid : Depth 75mm 100mmHollow : Depth 150mm 200mm 250mm

300mm 350mm 400mm450mm

Cross-sectional tolerances are within the limits set out in clause 6.2.8.3. of B.S. 8110:1997.Length tolerances are + 20 mm.

Bison units will have an upward camber due to pre-stressing as described in clause 6.2.8.4. of B.S.8110:1997.

Edges are shaped to form a grout joint givinga shear key to distribute load to adjacent units. Where non-standard widths are provided the edge will be rough cut from a standard unit.

FINISHESConcrete surface finish to soffit is Type A finish as described in clause 6.2.7.3. of B.S.8110:1997.

The soffit is suitable for the direct application of a textured paint finish where this is applied inaccordance with the manufacturers instructions.

Where a plaster finish is intended it may be necessary to use a bonding agent in accordance with the instructions of the plaster manufacturer.Plaster finishes are not recommended on longerspans.

Sides and top surfaces are ‘as extruded’ as described in Table 5.5 of B.S.8110:1997.

Units may accumulate water within the coresdue to exposure during the constructionprogramme. The General Contractor should drill weep holes as necessary, or keep them clear where they are provided during manufacture.

DESIGNThe design of Bison units is in accordance withthe requirements and recommendations of B.S.8110:1997 “The Structural Use of Concrete.”

Load/Span capacity : The reinforcementpattern within a Bison section will varyaccording to the design loading specified.

Exposure Condition : The standard Bisonsection is suitable for a moderate exposureclassification as defined in Table 3.2 ofB.S.8110:1997.

Fire Resistance : Fire resistance is based upon the tabulated data contained within B.S. 8110 Part 2 Section 4. Sections are available for fireperiods of 1 hour or 2 hours, without theaddition of further finishes.These periods offire resistance may be further enhanced by theapplication of appropriate finishes.

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1.2

1.3

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1.5

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2.2

2.3

2.4

B I S O N P R E C A S T F L O O R I N GS P E C I F I C A T I O N

Serviceability : The standard Bison section is designed to meet the criteria of Class 3 as set out in clause 4.1.3 of B.S.8110.1997 Designsto Class 1 and Class 2 are available if required.

Sound Insulation : The requirements of The Building Regulations are that a floor construction incorporating the use of precast concrete units should have a minimum mass which isdependent upon whether the finishes to the topsurface are directly applied or are on a separating layer. The mass of Bison unit sections aregiven in the technical data and are net weights of standard hollow sections. Futher informationis set out on page 12 of this brochure.

Horizontal & Vertical Ties : Ties necessary tosatisfy the requirements for accidental damage should be specified by the Engineer with responsibility for the design of the overall structure in accordance with the Codeof Practice.

Bearings : Level and structurally adequate bearings for Bison precast units should be provided by other contractors. These should generally be 100 mm for masonry or 75 mm for concrete or steelwork, but may be reduced in accordance with clause 5.2.3 of B.S.8110:1997.

Holes : Small holes up to 60 mm diametermay be drilled on site through the hollowcores, care being taken to avoid damage to thereinforced ribs. Larger holes may be cut subjectto the design capacity of the slab.

Grouting : Joints between units should begrouted with a 20 N/mm2 concrete using a 6 mm nominal aggregate size.

Propping : Where the slab design requires sitepropping, this should be carried out in strict accordance with the Bison drawings.

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4.10

4.11

QUALITY ASSURANCEAll Bison manufacturing plants are members of the B.S.I. Registered Firms Scheme forQuality Assurance to B.S. EN ISO 9001:1994for the design and manufacture of precastconcrete products.Membership of the scheme ensures that allprocedures and disciplines relevant to thedesign and manufacturing processes are subjectto the independent approval and periodicreview by the British Standards Institution.

All Bison U.K.factories have beenassessed by theBritish StandardsInstitution (B.S.I.)and awardedCertificates ofAssessed Capabilityunder the schemecovering QualityAssurance for themanufacture ofprecast concretefloors.

As a customer, you can be sure that all aspectsof our production, design detailing and qualitycontrol have been independently inspected andhave achieved the high level of competenceand quality required by the British StandardsInstitution. The company maintains a policy of continuousdevelopment, and reserves the right to changespecification and details without prior notice.

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REGISTRATION No. FM 11

HCF/ 02 / 04 5985Consortium Communications Ltd.Tel: 01494 681600 email: [email protected]

PRECAST STAIRCASES

BEAM AND BLOCK FLOORS

STRUCTURES

CAR PARKS

BISON CONCRETE PRODUCTS LIMITEDMillennium CourtFirst Avenue, Centrum 100Burton Upon Trent, DE14 2WRFAX 01283 544900 TEL 01283 495000E-MAIL [email protected] www.bison.co.uk

Bison Hollow Core Floors

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