Architectural Teaching Resource

STUDIO GUIDERevised 2002

The Steel Construction Institute

FOREWORD

This Studio Guide, which is also available in anelectronic format, provides an overview ofcommon structural steelwork solutions andcomplements the Corus Architectural TeachingProgramme distributed to all Schools ofArchitecture in the UK in 1990.

The Architectural Teaching Programmecomprises 36 lectures, over 1000 slides, videosand computer programmes, and provides acomprehensive review of the architectural aspectsof structural steelwork.

It is intended as an educational resource forarchitectural and engineering students and is asimple reference for use in practice.

General structural design information ispresented in good faith, but is intended only as aguide for student projects. Full structuralcalculations should be used in relation tobuilding projects.

The Studio Guide was written by Prof. RaymondOgden (SCI Professor in ArchitecturalTechnology at Oxford Brookes University), withcontributions from Professor Roger Plank ofSheffield University, and Dr Mark Lawson andJames Atree of the SCI.

Although care has been taken to ensure, to the best of our knowledge, that all data and information contained herein are accurate tothe extent that they relate to either matters of fact or accepted practice or matters of opinion at the time of publication, The SteelConstruction Institute, the author and the reviewers assume no responsibility for any errors or misinterpretations of such data and/orinformation or any loss or damage arising from or related to their use.

ISBN 1 85942 035 4

Publication Number SCI-P-167

© The Steel Construction Institute 2002

The Steel

Construction

Institute

Corus Construction Centre

Corus Construction Centre is an information source fordesigners and users of steel in the construction business.It provides a fast, efficient, ‘one-stop’ technical supportservice across all construction and construction-relatedproducts and applications. It can be contacted on asingle hotline number, 01724 40 50 60.

Corus Construction Centre PO Box 1 Scunthorpe North Lincolnshire DN16 1 BP

Tel +44 (0) 1724 405060 Fax +44 (0) 1724 404224 E-mail corusconstruction@corusgroup.comWebsite www.corusconstruction.com

The Steel Construction Institute is an independent,membership based organisation which was founded in1986 to develop and promote the effective use of steel inconstruction. Having developed a highly valuedframework for engineers, it is now involved in a numberof research programmes focused on architectural issuesincluding environmental projects.

For membership details (including studentmembership), and further information on publicationsand courses, please contact SCI.

The Steel Construction Institute Silwood Park Ascot BerkshireSL5 7QN

Tel +44 (0) 1344 623345 Fax +44 (0) 1344 622944 E-mail reception@steel-sci.comwww.steel-sci.org

PRODUCTSHot rolled steel structures 4Cold rolled steel structures 5Fabricated structural sections 5Light steel cladding 6Light steel decking 6

FRAMING SECTIONS Composite beam 7Slimdek 8Portal frame 9Trusses 10Space frames 11Long span structures 11Light steel frames 12Modular construction 13

CONNECTIONS Finplate beam to column 14Endplate beam to column 15Haunched beam to column 15Endplate beam to beam 15Pinned tube connection 15Column base connection 15Quicon connection 16

CLADDING SYSTEMSStrongback 17Integral 18Stick system 19Brick 20Light steel cladding 21Bolted glazing system 22

FIRE PROTECTION 23

FURTHER REFERENCE 24

CONTENTS

5

6

4

3

2

1

STUDIO GUIDE 1

Lowry Centre, Manchester

Peckham Library

Wilkinson E

yre (Nick W

ood)

Gateshead Millenium Bridge

Nicolas G

rimshaw

National Space Centre

Steel is synonymous with modern architecture.Throughout the twentieth century the material hasinspired architects and engineers, for it combinesstrength and efficiency with unparalleled opportunitiesfor sculptural expression. Today, in an era ofarchitectural pluralism, and of engineering innovation,steel plays a central role in many of the mostsophisticated and accomplished examples of modernbuilding design. Partly this is due to the strides thathave been made in metallurgy, structural analysis,fabrication and construction; but perhaps morefundamentally is testament to the continuingcommitment and fascination of architects and engineerswith a material that offers outstanding designopportunities.

Key attributes of steel include high strength andrelatively low weight, which gives remarkable spanningand load carrying ability. Steel lends itself toprefabrication. Whole structures can be created in afactory environment and then constructed quickly onsite. Steel building are highly adaptable in that framescan be modified and altered. Costs are low, recyclingsimple and aesthetic opportunities rich and varied. Asdesigners, fabricators and constructors continuallyadvance the boundaries of steel design, both technicallyand expressively, the role as core part of modernarchitecture seems assured.

Steel is basically iron and carbon however its propertiescan be enhanced and modified by the addition of otheralloying elements and by the manufacturing process. The material is then made into sections, plate or sheet,

and these simple products used to produce structuresand many other building components.

Standard approaches have evolved for many types ofstructure, the most common of which are described inthe following sections. They are not constraininghowever. Departures from norms are commonplace, forsteel lends itself to creative solutions. Modernarchitecture is rich with solutions that defy simplecategorisation.

The most widely used structural frames rely on hotrolled steel sections made from material that has beenheated and passed as a billet through heavy rollers thatgradually reduce the cross-section whilst at the sametime increasing length. Gradually the material flows tothe required shape. Simple wide span column and beamframes where the structural members are arranged in athree dimensional matrix like the solutions on pages 8,and portal frames such as that on page 9 are mainlybased on these sections.

For larger spans hot rolled sections and plate can befabricated to form particularly deep beams or otherstructural members such as those shown on page 11, andthe same technique can be used for geometricallycomplex members such as the roof beams on the RenaultCentre or the steel arch of Lehrter Bahnhof. Standardsections can also be curved after manufacture usingheavy bending equipment, or be converted to perforatedweb profiles using a variety of approaches some ofwhich split the beam into two and then reweld it so thatits depth and spanning ability is much increased.

INTRODUCTION

2 STUDIO GUIDE

Von G

erkan Mary A

rchitects

Steel Arch Lehrter Bahnhof, Berlin

Lighter steel sections can be formed by bending sheetsteel to C, Z or ‘ sections. Normally this is done usingeither a press or folding machine for special sections, ora cold rolling line for standard sections. Cold formedsections generally have greater structural capacity thanequivalent timber sections with common structuralprofiles ranging from around 75 to 500 mm. These areparticularly suitable for close centre frames such as walland floor panels, roof purlins that support cladding,light portal frames, beams and columns (where spansand loads permit), and for lightly loaded and non-structural applications such as support to internal wallsand partitions. Increasingly these sections are beingused for whole buildings such as houses, apartments,hotels and offices (page 12), and for modular buildings(page 13). Profiled cladding, floor decks and similarproducts are also produced by cold rolling.

Steel members can be joined using a wide variety oftechniques including welding and bolting (Page 14),and connection design is an important part of anystructural system. Like the structures of which they are apart, connection arrangements can be highlystandardised such as those on pages 15 and 16, orindividual such as the mast connection for theCommonwealth Games Stadium. Often in expressedsteelwork, connections become important architecturalelements in their own right.

This publication provides a simple overview of some ofthe basic constructional and structural concepts onwhich most buildings are founded, and also includesselected aspects of associated technologies such ascladding and fire protection.

The accompanying CD, aimed at architectural students,contains a concise structures course that can furtherinform the selection and development of structuralsolutions.

STUDIO GUIDE 3

Renault Building

Yorkon

Murray Grove (front elevation)

Curved beams at Helsinki Airport

Arup A

ssociates

Mast connection, Commonwealth Games Stadium, Manchester

Section Product Corus size range (mm)* Typical Uses

Universal Beam 1016 x 305 457 x 191 254 x 146 Beams(UB) 914 x 419 457 x 152 254 x 102

914 x 305 406 x 178 203 x 133838 x 292 406 x 140 203 x 102762 x 267 356 x 171 178 x 102686 x 284 356 x 127 152 x 89610 x 305 305 x 165 127 x 76610 x 229 305 x 127 533 x 210 305 x 102

Universal Column 356 x 406 305 x 305 203 x 203 Columns(UC) 356 x 368 254 x 254 152 x 152

Parallel Flange Channel 430 x 100 260 x 75 180 x 90 Channels(PFC) 380 x 100 230 x 90 180 x 75 Edge beams

300 x 100 230 x 75 150 x 90 Secondary steelwork300 x 90 200 x 90 150 x 75260 x 90 200 x 75 125 x 65

100 x 50

Equal angles 200 x 200 120 x 120 90 x 90 Truss members150 x 150 100 x 100 Bracing ties

Secondary steelwork

Unequal angles 200 x 150 150 x 75 100 x 65 Truss members200 x 100 125 x 75 Bracing ties150 x 90 100 x 75 Secondary steelwork

Square Hollow Sections 400 x 400 160 x 160 80 x 80 Columns(SHS) 350 x 350 150 x 150 70 x 70 Trusses

300 x 300 140 x 140 60 x 60250 x 250 120 x 120 50 x 50 Members subject 200 x 200 100 x 100 40 x 40 to torsion180 x 180 90 x 90

Rectangular Hollow Section 500 x 300 200 x 150 100 x 60 Columns(RHS) 450 x 250 200 x 120 100 x 50 Beams

400 x 200 200 x 100 90 x 50 Trusses300 x 200 160 x 80 80 x 40300 x 100 150 x 100 60 x 40 Members subject250 x 150 120 x 80 50 x 30 to torsion250 x 100 120 x 60

Circular Hollow Section 508 193.7 42.4(CHS) 457 168.3 26.9

406.4 139.7355.6 114.3323.9 88.9273 76.1244.5 60.3 219.1 48.3

Most of these sections are available in a range of cross-sectional thicknesses(usually termed weights). Refer to Corus section tables.

Asymmetric Beams 300 ASB (FE) 249 280 ASB (FE) 136 Slimdek® Floor BeamsASB 300 ASB 196 280 ASB 124

300 ASB (FE) 185 280 ASB 105300 ASB 155 280 ASB (FE) 100300 ASB (FE) 153 280 ASB 74

Section designated (FE) are Fire Engineering and can achieve 60 minutes fire resistance without fire protection. Slimdek® is a trade mark of Corus.

Rolled steel sections

4 STUDIO GUIDE

PRODUCTS1

Section Product Type size range*

Cellular beam 457 to 915 mm deep1.5 times the depth of the section from which the twohalves of the beam are cut.

Castellated beam 457 to 915 mm deep1.5 times the depth of the section from which the twohalves of the beam are cut.

Plate girder Bridge construction, often more than 1m deep (usuallywithout openings)Tapered sections and sections with openings can be usedin buildings 400 to 1000 mm deep

Section Product Common UK Size Range* Typical Uses

Channel 75 to 300 mm deep Lipped Structural frames JoistsStuds ColumnsUnlipped Connecting members in panels

Sigma 130 to 265 mm deep Sheeting rails PurlinsStudsJoists

Zed 140 to 300 mm deep Purlins Sheeting Rails

Light steel sections

*Cold-formed sections are manufactured by many different companies and size ranges vary. For actual sizes refer to manufacturers’information. Summary information on sizes of channel sections is contained in Building Design using Cold Formed Steel Sections: An Architect’s Guide, published by The Steel Construction Institute. These sections are typically 1.2 to 3.2 mm thick.

* Fabricated structural sections are manufactured by many different companies and size ranges vary. For actual sizes refer to manufacturers’ information.

1 PRO D U CTS

Section Product Type size range* Typical uses

Lattice Trusses 220 to 3000 mm deep Floor beams Roof trusses- curved- pitched- parallel chord

STUDIO GUIDE 5

Fabricated light steel sections

Fabricated structural sections

Profile Product Typical proportions*

Re-entrant Depth 51 mmDistance between dovetail centres 152 mm

Trapezoid Depth 46 to 80 mmDistance between trough centres 225 to 300mm

Deep Deck Depth 225 mmDistance between trough centres 600 mm

*Deck profiles are manufactured by many different companies and size ranges vary. For actual sizes refer to manufacturers information.

Profile Product Typical proportions*

Profiled Cladding Used in roofs and wallsDepth 30 to 60 mmWidth 900-1200 mm

Liner Sheets Used in built-up roofs with sheeting aboveDepth 10 to 30 mmWidth 900-1200 mm

Composite Panels Double skin panels with flat, ribbed or profiled external sheets. Various other materialsmay be used to provide the required insulationand strength characteristicsTypical thicknesses 35-100 mm

Standing Seam Roofing Permits relative movement of two roof panelsDepth 50 to 75 mmWidth 300 to 600 mm

Standing Liner Trays Used to span between rafters with roof sheeting overDepth 80 mmWidth 500 mm

*Sheeting profiles are manufactured by many different companies and size ranges vary. For actual sizes refer to manufacturers information.

Light steel cladding

Light steel decking (used for composite slabs)

1 PRO D U CTS

6 STUDIO GUIDE

Approximate structural sizingPRIMARY BEAMSMaximum span 15 mFloor beam depth Span/20Roof beam depth Span/25

SECONDARY BEAMSMaximum span 12 mFloor beam depth Span/25Roof beam depth Span/30Composite slab spans up to 3.6 m

ColumnsFLOORS UC SHS1 152 x 152 150 x 1502-4 203 x 203 200 x 2005-8 254 x 254 250 x 2509-12 305 x 305 300 x 30013-40 356 x 406 400 x 400

2 F RAM I NG SCH E M AT ICS

STUDIO GUIDE 7

KEY1 Composite slab

(a) concrete(b) steel deck(c) reinforcement

2 Primary beam3 Secondary beam4 Shear studs5 Column

FRAMING SCHEMATICS2

Composite beam

Primary and secondary beams incomposite steel frames are rigidlyconnected to the floor slab usingshear studs. This allows the floorslab, and the beams beneath, to actcompositely. Beam depths aretherefore less than in equivalentnon-composite frames.

Floor slabs generally compriseprofiled steel floor deck with in-situconcrete cast over the deck. The deck acts as permanentshuttering and spans in a directiontransverse to the secondary beams.

View perpendicular to span of floor deck View parallel to span of floor deck

1a

1c4

2

1b

1a

1c

4

2 or 3

1b

1a

1c

1

1b

2

5

34

Slimdek®

Slimdek® comprises an ASB steelsection contained within the depthof the slab. It supports deep deckprofiled floor decking. Ties runperpendicular to the beams.

The major advantage of Slimdek®

construction is that the beams arecontained within the floor depth.This reduces the overall height ofthe floor structure, and can improveservice integration.

Asymmetric beams (ASB) are hotrolled sections where the bottomflange is wider than the top flange.Spans of up to 9 m are possible.Some ASB sections have beenproportioned so that they canachieve up to 60 minutes fireresistance without applied fireprotection.

2 F RAM I NG SCH E M AT ICS

Detail

8 STUDIO GUIDE

1c

1a

5

2

4

3

2

1b

1a

1b

KEY1 Floor slab

(a) Concrete(b) Deep deck (c) Reinforcement

2 ASB3 Tie between frames4 Column

Slimdek® is a trademark of Corus.

Approximate structural sizingPRIMARY BEAMSMaximum span 9 mBeam depth Span/30Composite slab spans up to 9 m

Columns

FLOORS UC SHS1 152 x 152 150 x 1502-4 203 x 203 200 x 2005-8 254 x 254 250 x 2509-12 305 x 305 300 x 300

2 F RAM I NG SCH E M AT ICS

KEY1 Profiled cladding2 Insulation3 Liner sheet4 Spacer5 Purlin6 Side rail7 Portal frame

(a) roof beam(b) column

Portal frameSteel portal frames are capable ofspanning large distances. They areused in the construction of factoriesand warehouses, and other low-risebuildings that require wide spans.Wall and roof bracing is normallyprovided in selected bays, often atthe end of buildings. Additionalvertical column or beam sectionsmay be introduced at the gables(wind posts) to support cladding onend walls.

Roof beams (rafters) and columnsare usually fabricated from rolledsteel sections, while purlins andcladding rails are usually in lightsteel sections. Liner trays may beused as an alternative to claddingrails.

Cladding materials include built-upcladding systems (as shown),composite cladding panels, andmasonry.

Typical light steel cladding details are provided in Section 4.

Small single storey industrialbuildings can also be constructedusing light steel sections for thecolumns and rafters

STUDIO GUIDE 9

1

1

23

6

7b

4

5

3

2

7a

PURLINS Maximum span 4.5 – 7.5 mPurlin depth Span/35

LINER SHEETSTypical maximum span 3 mLiner depth 20 mm

PROFILED CLADDINGTypical maximum span 3 mProfile depth 35 – 40 m

Approximate structural sizingROOF BEAMS (RAFTERS)Typical span 20-50 mBeam depth Span/60Cold formed rafters span up to 18 m

COLUMNSColumn depth 1.25 x roof beamWidth as UB sections

TrussesSteel trusses are highly efficientstructural forms, able to spanconsiderable distances. They arevisually light and services can passthrough them.

Trusses may be fabricated from avariety of steel sections including:circular, square and rectangularhollow sections, angles, flats, rodsand cold-formed profiles. Circularhollow sections are often used forexposed architectural steelwork,and specialist machinery has beendeveloped to cut the complex tube-to-tube connections that arise atnodes where multiple tubesintersect. Columns are generallyUniversal Column sections (UCs),or Square or Circular HollowSections (RHS or CHS).

Trusses may have flat cross-sections (one chord normally abovethe other), triangular cross-sections, or occasionally may haverectangular cross-sections toaccommodate walkways orbuilding services.

The components (members) areusually fully welded, howeverlong members can be fabricated inseveral sections. Trusses arenormally connected to columnsusing bolts. Where trusses areconnected to RHS or CHS sectionsand it is not possible to installconventional nuts onto the end ofbolts inside the section,conventional bolts may be used inspecially threaded holes.Alternatively proprietary boltsmay be used that incorporate anexpanding sleeve.

Approximate structural sizing

ROOF BEAMSDepth Span/15Typical maximum length 60 m

FLOOR BEAMSDepth Span/12Typical maximum length 10 – 25 m

Space framesSpace frames are essentially threedimensional trusses able to span intwo directions. They may be flatfor use as roofs, walls or inclinedwalls, or may be curved to formcontinuous barrel type roofgeometries. Flat frames used asroofs sometimes have slightcambers to direct water toappropriate roof outlets. Space frames allow for easy servicedistribution within their depth andcan provide light elegant structuralsolutions.

SPACE FRAMESDepth Span/40Clear span 100 m

2 F RAM I NG SCH E M AT ICS

10 STUDIO GUIDE

1

2

3

3 3

1

1

2

1Pitched Truss

Flat Truss

3

Frank Gehry

Curved roof, Berlin

KEY1 Chord 2 Lattice 3 Column

2 F RAM I NG SCH E M AT ICS

Type:

Cellular beamsPerforations lighten sections and provide routes forbuilding services.

Long span structures

STUDIO GUIDE 11

Usual maximum span 15 mBeam depth Span/22

The merit of each of the above systems depends onspan, cost, degree of service integration, futureadaptability etc.

Haunched beamsRigid connections reduce overall beam depth.

Usual maximum span 18 mBeam depth Span/30

Fabricated beamsFabricated beams are usually used where long spansare required. The section is fabricated from threeplates welded together to form an I-section. It ispossible to design these sections with web openingsto allow for service integration.

Usual maximum span 15 mBeam depth Span/20

Composite trussesTrusses connected to floor slab using welded shearstuds. Trusses may use tee, angle or hollow sections.

Usual maximum span 30 mBeam depth Span/15

Stub girdersShort beam sections are welded to the top of beamsand support the floor slab. Service may pass throughvoids.

Usual maximum span 20 mBeam depth Span/15

Tapered beamsTapered sections provide service zone adjacent tocolumns.

Usual maximum span 25 mBeam depth Span/20

These systems incorporate facility for integration of large building services.

Alternative tapered beam profiles:

Light Steel FramesLight steel construction uses cold-formed steel channel sections thatare much thinner (typically 1.6 to 3.2mm) than hot rolled sections. Cold-formed sections are produced fromgalvanised steel. Sections normallyrange between 75 and 300 mm deep,and are available from variousmanufacturers.

Light steel frames normally combinemany different section sizes andincorporate steel floor joists, beams,columns, stud walls (load bearing)and partitions (non-load bearing).Connections are made using self-drilling, self-tapping screws, weldsor bolts.The frame is assembled onsite, usually from a series of panels.

Acoustic and fire resistance criteriaare important in separating wallsand floors. Floor beams may beused in conjunction with compositeslabs. Open roof structures may becreated using attic type trusses orpurlins spanning between flankwalls.

2 F RAM I NG SCH E M AT ICS

FLOOR JOISTS (SINGLE C)Maximum span 5 mSpacing 450 or 600 mmJoist depth Span/25Thickness 1.6 – 2.4 mm

BEAMS (DOUBLE C)Maximum span 6 mBeam depth pan/18Thickness 2.4 – 3.2 mm

STUDS (SINGLE C, 2 STOREY BUILDING)Spacing 450 or 600 mmDepth 75 – 100 mmThickness 1.6 – 2.4 mm

COLUMNS (DOUBLE C, 3 STOREYBUILDING)Spacing 4 – 6 mDepth 150 – 250 mmThickness 2.4 – 3.2 mm

KEY1 Floor joist2 Stud 3 Bracing4 Curved rafter

12 STUDIO GUIDE

Approximate structural sizing

1

2

3

4

Modular construction, sometimescalled volumetric construction,allows buildings or substantialparts of buildings, to be constructedin a factory environment. Wall,floor and ceiling frames can bemanufactured efficiently using lightsteel sections. Wall frames typicallycomprise vertical steel studs withtop and bottom tracks, and eitherbracing or sheathing boards toprevent racking. Floor and wallcassettes comprise horizontal joistsconnected together at both of theirends with a channel or similarsection. Alternatively they may beconstructed in-situ from individualmembers.

Two types of module are commonlyused: modules with columns thattransfer forces as point loads, andmodules with load bearing wallsthat transfer vertical forces alongtheir length in a similar fashion toconventional load bearingconstruction.

The size of modules is usuallydetermined by transport and liftingcriteria. Hotel rooms, studentstudy-bedrooms and bathrooms arenormally built as single modules,whilst larger spaces, such aspayment areas and shops at fillingstation, and fast food restaurantsare generally constructed fromseveral open sided modulesinstalled side by side.

Other important applications ofmodular construction includeprefabricated plant rooms andtoilets.

Structural sizes are similar to thosegiven for light steel frames in theprevious section.

Hybrid modular constructionimplies the use of modules withpanels or conventionallyconstructed building elements.Houses for example, may beconstructed with modules for thoseareas that require complex fitting-out such as kitchens, bathroomsand staircases, whilst the remainingareas (sometimes termed baggyspace) are constructed using panelsor built in-situ.

2 F RAM I NG SCH E M AT ICS

STUDIO GUIDE 13

Modular Construction

Yorkon

Murray Grove (rear elevation)

Yorkon

Murray Grove under construction

Fin plate beam to column connectionFin plate connections are fabricated by welding a singleplate to the column. Beams are normally attached usingtwo or more bolts. Where necessary, adjustment can beprovided using slotted holes (for instance horizontallyslotted holes in the web of the section attached to the finplate).

End plate beam to column connectionEndplate connections have a single plate welded to theend of the beam, which is bolted to the column usingtwo or more bolts arranged in pairs. Where necessary, adjustment can be provided by slottedholes and shims between the endplate and the section towhich is attached.

When connections are made to hollow section columns,it is not possible to install conventional nuts onto theends of bolts inside the section. Specially threaded holesusing the ‘Flowdrill’* method or proprietary bolts thatincorporate an expanding sleeve may be used.

*’Flowdrill’ is a trademark of Flowdrill BV.

Haunched beam to column connectionHaunched connections are used where there is a need toachieve high moment transfer. The haunch locallyincreases the effective depth of the section. Beams areattached using multiple pairs of bolts through anendplate. Little adjustment is possible. Haunchedconnections are common in portal frames.

KEY1 Fin Plate welded to column2 Bolts3 Column4 Beam

KEY1 End plate welded to beam2 Bolts3 Column4 Beam

KEY1 Haunched beam end2 Bolts3 Endplate4 Column5 Beam

14 STUDIO GUIDE

CONNECTIONS3

1

1

1

1

1

1

1 2

2

2

2

2

2

4

4

3

3

3

3

3

3

4

4

4

4

5

5

4

3

End plate beam-to-beam connectionThe end plate beam-to-beam connection is similar to thebeam to column endplate connection. However becausethe top flanges of the beams support floors or roofstructure directly, the top flange at the end of theincoming beam has to be notched. An alternative detailis to provide a projecting welded bracket or fin-plate onthe supporting beam. Adjustment is similar to the beamto column detail.

Pinned tube connectionThe ends of tubes can be profiled and welded, or can bebolted using simple fin-plates. Single fin-plates may bewelded to each of the members or, where eccentricitiesneed to be minimised, a single finplate on one membermay be designed to locate between a pair of fin-plates onthe other (as shown). Attachment is normally madeusing either bolts or pins.

Column base connectionThere are a variety of ways of connecting columnbaseplates to concrete ground structures. One commonmethod involves casting bolts, via bolt pockets, into theconcrete. Bolts are able to move slightly within thepockets to provide horizontal adjustment of thebaseplate before grouting the gaps around the bolts.Vertical adjustment is by shims or packs inserted beneaththe baseplate and the top surface of the concrete.

3 F RAM I NG CON N ECT ION S

KEY1 End plate welded to

supported beam2 Bolts3 Supported beam4 Supporting beam

KEY1 Fin-plate2 Bolt or pin3 Tubular section

KEY1 Bolt pockets cast in concrete2 Base-plate3 Column

11

2

2

3

3

3

3

4

3

1

1

2

4

3

3

3

1

1

STUDIO GUIDE 15

Arup A

ssociates

Mast base and pin, Commonwealth Games Stadium, Manchester

3 F RAM I NG CON N ECT ION S

Quicon connectionThe Quicon connection can be used for beam to columnor beam to beam connections. The connection uses aspecial connector component, which eliminates the needfor onsite bolting. The supporting member, either abeam or column, is fitted with a fabricated tee pieceusing ordinary structural bolts. The tee piece isfabricated with key hole shaped slots. The specialconnector is bolted to the supported beam prior toerection.

Using this type of connection improves the speed oferection which results in reduced construction costs.Safety on-site is also improved as site operatives spendless time aloft and do not need to carry equipment withthem.

KEY1 Tee piece2 Connector bolts3 Special connectors4 Column5 Supported beam

KEY1 Steel beam2 Concrete wall3 Bracket welded to beam4 Reinforcement bracket clamp5 Connecting rod6 Shims on grout bed7 Shear connector*8 Local additional reinforcement

*Option, do not omit both 4&7

16 STUDIO GUIDE

Steel to concreteMany building and refurbishment projects requirestructural connections between steelwork and concreteconstruction. For example a multi-storey building witha steel frame may rely on a concrete core for stability,this requires fixings to be made between the steelworkand the concrete.

For new construction connections are usually madeusing a steel bracket, which can be cast into the concreteelement prior to erection of the steelwork. Care shouldbe taken to ensure that the connection can be madequickly and safely during erection and sufficientadjustment is provided to meet erection tolerances.

In refurbishment work connections to existing concretestructures can present particular difficulties. Post drilledexpanding anchors of resin anchors are commonly used,but these must be positioned so that they do not clashwith reinforcing bars. This may mean that slotted holesare required in the fixing bracket or the fixing bracket isfabricated after suitable locations for the post drillanchors are determining on site.

4

4

3

1

1

6

7

35

6

2

7

5

8

Beam to Column

Beam to Beam

KEY1 Tee piece2 Connector bolts3 Special connectors4 Supporting beam5 Supported beam

1 Tee piece2 Connector bolts

21

1 Keyhole slot2 Special connector

21

Special ConnectorFabricated Tee Piece

3

12

3

2

5

1

4

54

StrongbackStrongback cladding systems have a sub-frame thatsupports thin cladding panels. Units are normallystorey height and up to 6 – 9 m wide. They are fixedeither to the edge of the floor slab or to the floor edgebeams or to columns. The supporting frame is usuallyconstructed from either hot rolled or cold-formed steelsections, or from stainless steel. Cladding materialsinclude stone, coated steel and stainless steel.

Panels are normally fixed to the building at fourpoints (two points at the top of the panel and two atthe bottom). They may be either hung from the topconnections or may bear on the bottom connections.Connections carrying the self-weight of the panel aretermed structural. Other connections act as windrestraints and prevent swaying, or overturning of thepanel, depending upon whether the panel is top hungor bottom supported. Provision is made at the fixingsfor building movements and tolerances.

Since panels can be relatively large, it is possible toclad buildings rapidly by using storey-high units.

CLADDING SCHEMATICS4

KEY1 Strongback2 Cladding3 Connection to building

a) Structural connectionb) Wind restraint

4 Floor slab5 Edge beam

Detail (bottom supported panel)

1 2

3b

3a

3b

3a

1

5

4

5

4

2

STUDIO GUIDE 17

IntegralIntegral cladding panels are generally made fromconcrete, and are able to support their own weight andresist wind loads without additional framing. As aresult they tend to be heavier than strongback panels(typically around 300kg/m2). Panels are normallystorey height and between 3 and 9 m wide.

They may be clad in other materials such as stone orceramic tiling. Panels may be top hung or bottomsupported and, like strongback panels, are normallyfixed to the building at four points (two points at the topof the panel and two at the bottom). Panels typicallybear on the slab edge using ‘boots’ (projecting concretenibs) or bolted-on brackets.

Two structural connections are normally made at thepoints of bearing, with two wind restraint connections atthe opposite edge (refer to strongback description fordefinitions). Bolted on brackets take up less, spacewhich is particularly advantageous in buildings withoutraised floors where boots can be difficult toaccommodate.

4 CL ADDI NG SCH E M AT ICS

18 STUDIO GUIDE

Detail (top hung panel)

KEY1 Panel2 Connection to building

a) Structural connectionb) Wind restraint

3 Floor slab4 Edge beam

2a

4

1

3

2b

3

4

2b

1

2b

2a

2a

Stick systemStick cladding systems comprise a series of verticalmembers (mullions) and horizontal members (transoms)that form a grid. This grid is used to restrain eithersolid panels or glass using rubber gaskets, and isnormally fixed to the floor edges by specially designedbrackets, which provide wind restraint (refer strongbackdescription for definitions). The self-weight of thecurtain wall is normally taken to the ground through themullions.

Stick systems are amongst the lightest forms of cladding(typically 50 kg/m2). Mullion spacings are normally inthe range 1.2 – 2 m, although wider spacings arepossible. Transom spacings are normally determined bypanel requirements and the architectural treatment ofthe façade.

Stick systems can be ‘unitised’ whereby horizontal andvertical members are prefabricated into units, which arecraned onto the façade. Special edge members havebeen developed for these systems.

4 CL ADDI NG SCH E M AT ICS

STUDIO GUIDE 19

KEY1 Glazed panel2 Mullion3 Transom4 Fixing bracket5 Floor slab6 Edge beam

3

2

5

4

5

62

1

Detail (Top hung panel)

Rautaruukki O

yj

Kone Building

BrickMulti-storey frames may be clad in brickwork or stoneusing a range of proprietary systems based on speciallydesigned brackets and restraint devices.

The most common method of attaching brickwork tosteel frames is by the use of shelf angles fitted either tothe slab edge, or to plates welded onto the edge beams.The shelf angles are usually made from stainless steel.The method of attachment of the shelf angle allows forvertical adjustment to suit the brick coursing.Brickwork is constructed on these shelf angles andattached to the columns and to inner concrete blockwalls using brick ties. Windposts are sometimesincorporated to give improved stability, particularly intall buildings subject to high wind pressures, or wherelarge size panels are used. An expansion joint is used atthe top of the panels to take up relative movementsbetween the building frame and the brickwork.

4 :CL ADDI NG SCH E M AT ICS

20 STUDIO GUIDE

KEY1 External brickwork2 Internal brickwork3 Shelf angle4 Windpost5 Column6 Edge beam7 Floor slab

1

1

4

1

2

3

4

5

3

6

2

6

7

4 CL ADDI NG SCH E M AT ICS

Light steel cladding

Built-up system with liner sheetThese systems comprise two separate cladding sheets:an external sheet, which is coloured and highlyprofiled, and a more lightly profiled inner liner sheet.The sheets are separated by spacer rails and insulation.The liner sheet and spacers are fixed to cladding railsthat span between columns. The external sheet is fixedto the spacer. The normal method of attachment is byself-drilling, self-tapping screws.

Built-up system with liner traysLiner trays span between columns and replace the linersheet, cladding rails and spacer rails. Insulation is setwithin the liner trays and the external cladding sheet isfixed directly onto the outer flanges of the tray.

Composite panel systemComposite panels have a sandwich constructioncomprising two steel sheets bonded either side of aninsulating core of foam, mineral fibre or similarmaterial. The bonded panel produces good stiffness,and both profiled and smooth surfaces are available.Panels may be fixed using a variety of techniquesincluding self-drilling, self-tapping screws, and secret-fixing brackets located within the panel joints.

STUDIO GUIDE 21

4 CL ADDI NG SCH E M AT ICS

The use of sophisticated bolted glazing systems, whereglass panels are attached directly to structural steelworkwithout using any intermediate framing, has grownsignificantly in recent years. Bolts attach the glass tobrackets on the steel through pre-drilled holes in theglass panes. The bolts provide point support instead ofthe continuous edge support given by conventionalframes.

Vertical glazing panels, up to 2m x 2m, can generally besupported using four corner fixings, whilst larger panels,up to 2m x 4m, typically require 6 fixings. Horizontaland inclined glazing may require more frequentsupports.

Various types of bolted fixing have been developedranging from simple bolts where the head is proud of thesurface of the glass, to countersunk designs which arerecessed into the glass and articulated bolts that allowsome rotation of the fixing as the glass panels, and thesupporting structure bend under the combined effects ofself weight and applied loads. This latter type of fixing isoften used in conjunction with large panes on tall, orlonger span, steel structures.

22 STUDIO GUIDE

Bolted Glazing Systems

Glazed entrance hall, NatWest Tower, London

Credit

Caption

Adjustment

Shims

Serratedfaces forverticaladjustment

Adjustment

Buro H

appold

Spider fixing detail

There are four common methods offire protecting structural steelwork;intumescent coatings, board basedsystems, sprayed materials andconcrete encasement or filling.

Intumescent coatings may be brushedor sprayed onto steelwork rather likepaint. The materials expand whensubjected to fire and form aninsulating foam. Intumescentcoatings can achieve up to 120 minutes fire resistance, and areused mostly on exposed steelwork.

Board based systems are used to formrectangular encasements around steelmembers, such as internal beams andcolumns. Paint or other finishes canbe applied directly to the boards. The level of fire resistance achieveddepends upon the type and thethicknesses of the boards used andupon the method of attachment.

Sprayed fire protection systems areusually based upon cementitiousmaterials and are applied directlyonto the surface of steelwork. Theyare generally low cost, but cannotreceive finishes owing to their coarseuneven texture. Sprayed materialstend to be used where steelwork isconcealed or where appearance isunimportant. Fire resistance issimilar to that of board basedmaterials.

Sections with Inherent FireResistance

Concrete Filled Structural HollowSectionsStructural Hollow Sections (SHS) canbe fire protected by filling withreinforced concrete. Concrete filledstructural hollow sections can achieve120 minutes fire resistance.

Slimdek®

The Slimdek® system has inherent fireresistance as the ASB section isencased in concrete with only thebottom flange exposed to fire.Without fire protection Slimdek® canachieve 60 minutes fire resistance.

Periods of fire resistance in excess of120 minutes can be achieved if ASB isfire protected.

Multi-storey frames requiring 30-60minutes can have 40% of the floorbeams unprotected by following therecommendations of a special designguide.

Protection thicknessesThe section factor of a particular steelsection is its surface area per unitlength divided by its volume per unitlength (A/V). This parameter defineshow quickly a steel section will heatup when subjected to fire. The sectionfactor for a member with boxprotection is lower than that for amember with profile protection, andhence box protected steelwork heatsup more slowly and requires lessprotection.

Typical spray or board thicknesses fora column in a multi-storey buildingare as set out in the table below.

Table 1: Typical spray or board thicknessesbased on 254UC x 89 kg/m column in amulti-storey building.

Fire Profile Box resistance protection protection(minutes) (mm) (mm)

30 10 1260 18 1590 24 20120 30 25

FIRE PROTECTION5

Intumescent coatings

Board based system

Sprayed materials

Concrete filling

STUDIO GUIDE 23

Cladding

Colorcoat in Buildings: a Guide to Architectural Practice. British Steel Strip Products, 1990

OGDEN R G Interfaces: Curtain Wall Connections to Steelframes. SCI-P-101, 1992

Composite Construction

LAWSON R M Design for Openings in the Webs ofComposite Beams. SCI-P-068, 1987

OWENS G W Design of Fabricated Composite Beams inBuildings. SCI-P-059, 1989

Couchman G H et al Composite Slabs and Beams usingSteel Decking: Best Practice for Design and Construction.SCI-P-300,2000

Light Steel

LAWSON R M et al Building Design using Cold FormedSteel Sections: Structural Design to BS 5950-5: 1998. SCI-P-276, 2002

CLOUGH R H and OGDEN R G Building Design usingCold Formed Steel Sections: Acoustic Insulation. SCI-P-128, 1993

LAWSON R M Building Design using Cold Formed SteelSections: Fire Protection. SCI-P-129, 1993

The Steel Construction Institute Case Studies on LightSteel Framing – First Series. SCI-P-176A 1997

The Steel Construction Institute Case Studies on LightSteel Framing – Second series. SCI-P-176b, 2000

LAWSON R M et al Modular Construction using LightSteel Framing: An Architects Guide. SCI P-272, 1999

Long Span Structures

LAWSON R M and RACKHAM J W Design of HaunchedComposite Beams in Buildings. SCI-P-060, 1989

NEAL S and JOHNSON R Design of Composite Trusses. SCI-P-083, 1992

BRETT P and RUSHTON J Parallel Beam Approach – A Design Guide. SCI-P-074, 1991

MacDERMOTT-SMITH M Design in Steel 1 – The ParallelBeam Approach. British Steel Sections

LAWSON R M and McCONNEL R Design of StubGirders. SCI-P-118, 1992

Slim Floor

MULLETT D M and LAWSON R M Slim FloorConstruction using Deep Decking. SCI-P-127, 1993

MULLETT D M Slim Floor Design and Construction. SCI-P-110, 1992

Corus Construction Centre Slimdeck Manual Corus UK Ltd, 2001

MCKENNA P D and LAWSON R M Service Integrationin Slimdek. SCI-P-273, 2000

LAWSON R M et al Design of Asymetric Slimflor Beamsusing Deep Decking. SCI-P-175, 1997

Fire

Fire Resistant Design of Structural Steelwork: InformationSheets. Corus Group

Fire Protection for Structural Steel in Buildings.Association of Specialist Fire Protection Contractors andManufacturers Limited, Steel Construction Institute andFire Test Study Group, 3rd Edition – 2002

LAWSON R M and NEWMAN G M Fire ResistantDesign of Steel Structures – a Handbook to BS 5950 Part 8. SCI-P-080, 1990

HAM S J et al Structural Fire Safety: A Handbook forArchitects and Engineers. SCI P-197, 1999

NEWMAN G M et al Design of Steel Framed Buildingswithout Applied Fire Protection. SCI-P-186,1999

NEWMAN G M et al Fire Safe Design: a New Approach toMulti Storey Steel Framed Buildings. SCI-P-288, 2000

24 STUDIO GUIDE

FURTHER READING6