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February 2007

DESIGN MANUAL FOR ROADS AND BRIDGES

VOLUME 2 HIGHWAY STRUCTURES:DESIGN(SUB-STRUCTURES ANDSPECIAL STRUCTURES),MATERIALS

SECTION 2 SPECIAL STRUCTURES

PART 1

BD 94/07

DESIGN OF MINOR STRUCTURES

SUMMARY

Summary

This Standard covers the design of minor highwaystructures, including:

• lighting columns;

• cantilever masts for traffic signals and/or speedcameras;

• CCTV masts;

• fixed vertical road traffic signs.

It incorporates the provisions of BS EN 40,BS EN 12899, and supersedes BD 26/04, BD 83/01 andBD 88/05.

INSTRUCTIONS FOR USE

1. Remove BD 26/04 from Volume 2, Section 2,Part 1.



4. Insert BD 94/07 into Volume 2, Section 2, Part 1.

5. Please archive this sheet as appropriate.

Note: A quarterly index with a full set of VolumeContents Pages is available separately from TheStationery Office Ltd.

BD 94/07Volume 2, Section 2,Part 1

Design of Minor Structures

Summary: This Standard covers the design of minor highway structures, including:

• lighting columns;

• cantilever masts for traffic signals and/or speed cameras;

• CCTV masts;

• fixed vertical road traffic signs.

It incorporates the provisions of BS EN 40, BS EN 12899, and supersedesBD 26/04, BD 83/01 and BD 88/05.


THE HIGHWAYS AGENCY

TRANSPORT SCOTLAND

WELSH ASSEMBLY GOVERNMENTLLYWODRAETH CYNULLIAD CYMRU

THE DEPARTMENT FOR REGIONAL DEVELOPMENTNORTHERN IRELAND

Volume 2 Section 2Part 1 BD 94/07

February 2007

REGISTRATION OF AMENDMENTS

Amend Page No Signature & Date of Amend Page No Signature & Date ofNo incorporation of No incorporation of

amendments amendments

Registration of Amendments

VOLUME 2 HIGHWAY STRUCTURES:DESIGN(SUB-STRUCTURES ANDSPECIAL STRUCTURES),MATERIALS

SECTION 2 SPECIAL STRUCTURES

PART 1

BD 94/07

DESIGN OF MINOR STRUCTURES

Contents

Chapter

1. Introduction

2. General Principles

3. Dimensional Limitations

4. Use of British Standards and Standards Issued byOverseeing Organisations

5. Design

6. Fibre Reinforced Polymer Composite LightingColumns

7. Door Openings

8. Wall Mounted Brackets

9. Attachments

10. Flange Plate Connections Between Structure andFoundation

11. Foundations

12. References

13. Enquiries

Annex A Limit States for Cantilever Masts

Annex B Fatigue Checks of Steel Structures andGuidance for Weld Classification

Annex C Detailed Design of Flange Plates

Annex D Determination of Shape Coefficients byTesting


February 2007


Chapter 1Introduction

1. INTRODUCTION

Mandatory Sections

Sections of this document which form part of thestandards of the Overseeing Organisations arehighlighted by being contained in boxes. These arethe sections with which the Design Organisationsshall comply, or shall have agreed a suitabledeparture from standard with the relevantOverseeing Organisation. The remainder of thedocument contains advice and enlargement whichis commended to Design Organisations for theirconsideration.

General

1.1 This Standard covers the use of the relevant parts(as defined herein) of BS EN 40 for the structuraldesign of:

• lighting columns made from concrete, steel,aluminium, and fibre reinforced polymercomposite (FRPC);

• cantilever masts for traffic signals and/or safetycameras (hereafter called cantilever masts) madefrom steel;

• closed circuit television (CCTV) masts madefrom steel;

• fixed vertical road traffic sign/signal posts.

Notes:

(i) Guidance and background information in the useof BS EN 40-3-1 and BS EN 40-3-3 for thedesign of lighting columns is given in PD6547:2004

(ii) This Standard covers the use of The Institution ofLighting Engineers Technical Report Number 7,High Masts for Lighting and CCTV, 2000 Edition(amended 2003), Sections 1 and 2 (ILE TR7) forthe design of CCTV masts. This TechnicalReport was originally developed for high mastlighting and has been revised to include CCTVmasts as they have similar features.

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Requirements for the design of fixed verticalroad signs are given in BS EN 12899: Part 1.These requirements are supplemented by thisStandard.

ets out the Overseeing Organisation’s particularuirements where these augment, or are additional tose given in the British Standard. In addition, thendard gives the requirements for lighting columnsde essentially from glass fibre reinforced plasticP). The technical basis for the clauses on FRP isited and it may become necessary in due course toiew the requirements, on the basis of theirformance in service.

Where materials other than concrete, steel,aluminium or FRPC are used for other minorstructures a departure from standards shall besought from the Technical Approval Authority.

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This Standard sets out the structural designuirements for the following minor highwayctures for use on trunk roads including motorways:

lighting columns and wall mounted bracketsmade from concrete, steel, aluminium, concreteand FRPC, including lighting columns mountedon other structures, e.g. on bridges;

steel CCTV masts mounted on foundations in theground. The requirements for CCTV mastsmounted on other structures eg gantries areoutside the scope of this Standard;

cantilever masts made from steel for trafficsignals and/or speed cameras. This Standardexcludes the design requirements for permanentand temporary cantilever sign and signal gantriesfor which BD 51 (DMRB 2.2.4) shall be used;

fixed vertical road traffic sign/signal posts. ThisStandard excludes the electronic designrequirements of certain traffic signs, as defined inEN 12899-Part 1.

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Chapter 1Introduction

Notes:

(i) The structural requirements for lattice structuresare outside the scope of this Standard; refer toBS8100 or any other relevant standard.

(ii) The structural requirements for passively safestructures should comply with this Standard butthe passive safety characteristics of suchstructures are dealt with in EN 12767 withguidance in TA 89.

(iii) In Northern Ireland this Standard applies tominor structures on all classes of road

Equivalence

1.3 Where minor structures are procured through acontract incorporating the Specification for HighwayWorks (MCHW 0 to 6) products conforming toequivalent standards or specifications of other memberstates of the European Economic Area will beacceptable in accordance with the terms of the 104 and105 Series of Clauses of that Specification. Anycontract not containing these Clauses must contain asuitable clause of mutual recognition having the sameeffect regarding which advice should be sought.

1.4 Where this Standard requires tests to be carriedout the results of tests undertaken by a body orlaboratory in a member state of the European EconomicArea will be accepted provided that the body orlaboratory offers suitable and satisfactory evidence oftechnical and professional competence andindependence. This requirement will be satisfied if thebody or laboratory is accredited in a member state ofthe European Economic Area in accordance with therelevant parts of the EN 45000 series of standards forthe tests carried out.

Implementation

1.5 This Standard should be used forthwith on allschemes for the construction and improvement of trunkroads, including motorways, currently being prepared,provided that, in the opinion of the OverseeingOrganisation, this would not result in significantadditional expense or delay progress. DesignOrganisations should confirm its application toparticular schemes with the Overseeing Organisation.Where the Overseeing Organisation’s contractdocuments are based on the Specification for HighwayWorks (MCHW 1) use of this Standard is mandatory. InNorthern Ireland this Standard should be used on all

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chemes for the construction and improvement to roadsesignated by the Overseeing Authority. Where thistandard duplicates or covers requirements in existingtandards during a period of co-existence, it shall takerecedence unless otherwise agreed with theverseeing Organisation.

February 2007


Chapter 2General Principles

2. GENERAL PRINCIPLES

Siting

2.1 The siting of minor structures shall accordwith the TDs and TAs as shown in Table 1 asrelevant to the structure considered. This shallinclude consideration of visibility by theapproaching traffic.

TD9 TD18 TD19

Lighting columns

Cantilever masts

CCTV masts

Road traffic signs

Table 1: TDs an

NOTE: Where possible cantilever masts should not be locate

Layout

2.2 All elements of minor structures shallcomply with the clearances specified in TD 27(DMRB 6.1.2) after allowing for deflections due todead, live, wind and High Vehicle buffeting loads.

2.3 The clear new construction headroom forroutes other than high load routes shall be 5,700mm minimum, as defined in TD 27 Table 8(DMRB 6.1.2) for Footbridges and Sign/SignalGantries. Where cantilever masts are sited on highload routes, the clear new construction headroomshall be 6,450 mm minimum, as defined in TD 27Table 8 (DMRB 6.1.2). In addition to structuraldeformations, consideration shall be given tosettlement when calculating headroom.

2.4 Requirements for the vehicle restraintsystem shall be agreed with the Technical

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TD23 TD33 TD34 TA74

d TAs

d on under-bridges.

pproval Authority. The setback of the vehiclestraint system to the edge of the carriageway

hall be in accordance with the requirements of theverseeing Organisation. Where passively safe

ignposts, lighting columns or traffic signal postsre provided, in accordance with TA 89/05, furtherehicle restraint systems shall not be required,nless required by the existence of other hazards.

.5 The clearance from the front of the vehiclestraint system to the face of the minor structure

hall be selected from the Working Width given inS EN 1317, Part 2, or other relevant standards.

rotection for Road Users and Structure

.6 Cantilever masts and CCTV masts shall becated either:

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Chapter 2General Principles

(i) more than 4.5 metres from the edge of thecarriageway closest to the post (the edge ofthe carriageway shall be as defined in BD 37(DMRB 1.3)); or

(ii) on a slope such that the underside of theflange plate is more than 2 metres verticallyabove the edge of the carriageway closest tothe post; or

(iii) behind a safety barrier conforming to therequirements of TD 19 (DMRB 2.2.8) andan appropriate working width.

Positioning of cantilever masts and CCTV masts inother locations shall be subject to the approval ofthe Technical Approval Authority.

2.7 Where the post of the cantilever mast orCCTV mast is located behind a vehicle restraintsystem meeting the requirements of BS EN 1317:Part 2, further vehicle restraint systems are notrequired.

Equipment

2.8 All luminaires, lanterns, brackets, signs,traffic signals, speed cameras and associatedequipment shall be securely attached to thestructure using vibration resistant fixings strongenough to withstand design loads. The structuraldesign shall make adequate provision for theattachment of equipment. Any subsequentmodifications to structural members shall only becarried out with the approval of the TechnicalApproval Authority in accordance with BD 2(DMRB 1.1.1) (refer to Chapter 4).

In-Situ Connections

2.9 In situ connections of main structural metalelements shall be by means of bolts. If other formsof in-situ connection are proposed then their staticand fatigue design strength shall be calculatedfrom first principles and shall be agreed with theTechnical Approval Authority. Alternatively, thedesign strength may be based on the results of full-scale load tests, subject to the agreement of theTechnical Approval Authority.

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Identification

2.10 In England and Wales the structure siteidentification marking shall be in accordance withBD 45 (DMRB 3.1.1). In Scotland, TransportScotland shall be consulted whilst in NorthernIreland the Roads Service shall be consulted.

Where not readily identifiable by the design,structures that have been designed to be passivelysafe to EN 12767 shall be marked to differentiatethem from other types of structures. The markingsystem will incorporate the phrase “CrashFriendly” and be placed on the post or column in aposition that will not affect the functionality of anypart of the assembly or the identification marksrequired by BD 45 (DMRB 3.1.1). The form ofmarking appropriate for individual products shallbe agreed with the Overseeing Organisation.

Use of Dissimilar Metals

2.11 Where dissimilar metals are to be used, theconnections shall be designed to avoid the risk ofgalvanic corrosion. The electrical bonding of allmetal components shall nonetheless be maintained.

Protection Against Corrosion

2.12 Surface preparation and paint protection ofsteel shall comply with the relevant clauses of theSeries 1900 in the Specification for HighwayWorks (MCHW 1).

2.13 For materials other than steel it shall bedemonstrated that they will have a life expectancygreater than the service life. (e.g. galvaniccorrosion of aluminium due to local groundconditions and UV degradation of FRPC columns).

February 2007


Chapter 3Dimensional Limitations

IONS
3. DIMENSIONAL LIMITAT
Lighting Columns

3.1 The dimensional requirements for lightingcolumns are given in EN40-2. The overalldimensional limitations for the lighting columnscovered by this Standard shall be:

For steel, aluminium, FRPC and concrete columns:

(i) post top columns< 20 m nominal height

(ii) columns with brackets< 18 m nominal height

(iii) bracket projections- not exceeding the lesser of 0.25 x nominalheight or 3 metres

NOTE: Nominal heights and bracket projections aredefined in BS EN 40-2: 2004.

CCTV Masts

3.2 The nominal height of steel CCTV mastscovered by this Standard shall be less than or equalto 25m. The nominal height is taken as the verticaldistance between the underside of the flange plateand the top of the mast.

NOTE: The nominal height excludes the height ofcamera, mounting etc (refer to Figure 1).

3.3 The design height of a CCTV mast shall betaken as the vertical distance between theunderside of the flange plate and the top of theCCTV mast or camera in its operating position, orother attachments, whichever is greater.

NOTE: The “design height” is different to the“nominal height” and is required for wind loadingcalculations (refer to Figure 1).

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OTES: The definitions given in ILE TR7, Section 1.4hould be interpreted as follows:

i) HIGH MAST shall also refer to CCTV masts,meaning the support intended to hold one ormore CCTV cameras with their mountings andhousings.

ii) The term LUMINAIRE shall be taken asincluding CCTV cameras, their mountings andhousings.

iii) ILE TR7 may be used in the design of CCTVmasts less than 10m in height.

Cantilever Masts

3.4 For cantilever masts, as shown in Figure 1:

(i) Nominal Height ≤ 8.5m

Where nominal height is taken as thedistance between the underside of the flangeplate and the highest point on the mast. (SeeFigure 1.)

(ii) Cantilever Projection ≤ 8.5m.

(iii) The horizontal projected area of any signs,traffic signals, speed cameras and associatedequipment, suspended above thecarriageway shall not exceed 1.2m2 and thevertical projected area shall not exceed0.3m2.

Traffic Sign/Signal Posts

3.5 The nominal height of traffic sign/signalposts shall be ≤ 9m.

NOTE: Above this height dynamic factors andfatigue shall be considered.

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Chapter 3Dimensional Limitations

Figure 1 General Arrangement of Cantilever Mast and CCTV Mast and StructuralDeformations of Cantilever Masts (see Table A2)

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February 2007

Chapter 4Use of British Standards and Standards Issued by the Overseeing Organisations

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4. USE OF BRITISH STANDARDS AND STANDARDSISSUED BY THE OVERSEEING ORGANISATIONS

4.1 The design, manufacture and installation oflighting columns and cantilever signal masts shallcomply with the following:

• Lighting columns and cantilever signalmasts – the relevant parts of BS EN 40.

• CCTV masts – ILE TR7.

• Road traffic sign posts – BS EN 12899-1.

All as implemented by this Standard and by theSpecification for Highway Works (MCHW 1),hereinafter referred to as “the specification”.

4.2 The specific Overseeing Organisation’sprocedures for the Technical Approval of minorstructures for use on motorways and other trunk roadsare given in BD 2 (DMRB 1.1).

Note: In Northern Ireland the procedures apply to minorstructures on all classes of road.

4.3 For minor structures at very exposed sites,the Technical Approval procedures for high masts,given in BD 2 (DMRB 1.1) shall apply. Lightingcolumns, CCTV masts, road traffic sign/signalposts and cantilever masts shall be classified asCategory 1 in accordance with BD 2 (DMRB1.1.1).

4.4 Within the United Kingdom, very exposed sitesare defined as:

(a) sites at high altitude, above 250m;

(b) sites within 5km from the coast; and

(c) sites subject to significant local funneling.


Chapter 5Design

5. DESIGN

General Requirements

5.1 Minor structures shall be designed inaccordance with the relevant requirements of thestandards listed in paragraph 4.1, as implementedby the Specification for Highway Works(MCHW1) and by this Standard.

Structural Criteria

5.2 The design life shall be 25 years, unlessotherwise required by the Technical ApprovalAuthority.

Limit States

5.3 Minor structures shall be designed to satisfythe relevant ultimate limit states and theserviceability limit state, including, for steelstructures, meeting fatigue criteria.

Lighting Columns:

5.4 For lighting columns the partial safetyfactors and criteria for serviceability and ultimatelimit states shall be taken as Class B as given inBS EN 40-3-3.

The horizontal deflections of each lanternconnection shall conform to class 2 as specified inBS EN 40 3-3 Table 3.

CCTV Masts:

5.5 For CCTV masts the partial safety factorsand criteria for serviceability and ultimate limitstates shall be as given in ILE TR7, Clauses 2.4and 2.5.

NOTE: For the serviceability limit state:

(i) Add at the end of ILE TR7 Section 2.3.2.3:“This calculation shall take full account ofthe actual weights of the CCTV mast,cameras, mountings, housings and any otherattachments. The Overseeing Organisationmay define more stringent rotation anddeflection criteria if required.”

February 2007

(ii) Using the terminology adopted by ILE TR7,at the serviceability limit state:

Ve = 22 m/s; (at 10m above groundlevel)

the corresponding dynamic wind pressure

qHe = 0.613Ve2; and

the peak equivalent static pressure:

EqH = qHe.δ.β

where δ = size reduction factor; and

β = dynamic response factor.

(iii) Vehicle collision loads do not need to beconsidered because of the requirementsimposed by clause 2.6.

Cantilever masts for traffic signals and/or speedcameras:

5.6 Cantilever masts for traffic signals and/orspeed cameras shall meet the criteria of 5.6.1 to5.6.3.

5.6.1 Three limit states are specified in Table A1of Annex A of this Standard with values of thepartial factor γF given; these cover strength, fatigueand deflection. Where any permanent load has arelieving effect γF shall be taken as 1.0 in both theultimate limit state and serviceability limit state.

Note: Vehicle collision loads shall not beconsidered.

5.6.2 In the serviceability limit state under loadingcombination 1, the deflections and rotations due towind loading only shall be limited such that thedeformations do not exceed the values given inTable A2 of Annex A*.

* More stringent deflection limits shall benecessary when the performance requirements ofthe equipment to be mounted so require them.

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Chapter 5Design

5.6.3 The deformation at the extremities of thestructural support shall be derived from the sum ofthe components of the effects of the load in thesupport posts, cantilever and sign supports, [seeFigure 1].

Road Traffic Sign Posts:

5.7 For road traffic sign posts the partial safetyfactors and criteria for serviceability and ultimatelimit states are given in BS EN 12899-1 and theUK’s National Annex.

Minimum Thickness of Steel Sections forCantilever Masts

5.8 The minimum thickness of structural steelsections used in cantilever masts shall be asfollows:

(i) plates and sections other thanhollow sections: 6 mm

(ii) hollow sections effectivelysealed by welding, other than asmall drain hole with a diameterof between 10mm and 15mm: 5 mm

Closed Hollow Sections for Cantilever Masts

5.9 Steel hollow sections used in cantilevermasts shall be designed to resist the ingress andretention of water or moisture by gravity flow,capillary action or condensation. The plates used toclose the open ends of hollow sections shall be ofthickness not less than the lesser of the following:

(i) the thickness of the walls of the hollowsection;

(ii) 8 mm.

The end plates shall be joined by continuousstructural quality welding to BS EN 1011: Parts 1and 2. Should there be a possibility of waterentering and subsequently freezing, then drainholes shall be provided. The size of the hole shallbe appropriate to the void being drained, but shallnot be less than 10 mm or greater than 15 mmdiameter. Hollow sections in non-corrosive orgalvanised steel shall be provided with such drainholes at all low points.

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Fatigue Criteria for Steel Structures

5.10 The rules set out in 5.10 to 5.16 shall beused for steel lighting columns 9m and above inheight and to all steel cantilever masts. These rulesmay not be applicable to very exposed sites; insuch cases the design shall be subjected toTechnical Approval procedures as set out in 4.3.Structures in materials other than steel are notcovered by the fatigue rules in this Standard and insuch cases the design shall be subjected toTechnical Approval procedures as set out in 4.2.

In all cases the procedures to be used for fatigueassessment shall be agreed between the designer,the client and the Overseeing Organisation, see 4.2above.

5.11 The stringent deflection requirements for thedesign of CCTV masts mean that stress rangesinduced by dynamic response to wind loading arelikely to be low. Thus fatigue is unlikely to be acritical design condition provided suitable detailsare used. However for CCTV masts sited in veryexposed locations, as defined in 4.4 fatigue shallbe considered.

5.12 Fatigue damage is most likely to occur at oradjacent to welds or near sharp corners creatingstress concentrations; particularly vulnerablepositions are:

(i) flange plates:

• at the weld throat between the columnand flange;

• in the parent metal adjacent to the weld;

(ii) door openings:

• at welded attachments;

• at poorly finished cut edges;

(iii) at any stiffening between the column and theflange;

(iv) shoulder joints:

• at the weld throat;

• in the parent metal adjacent to the weld.

February 2007


Chapter 5Design

At such positions, fatigue prone details should beavoided.

5.13 Fatigue is critically dependent ongeometrical configurations and fabrication.Stiffened and unstiffened door openings shouldcomply with the constraints shown in Figure 2. Inaddition the following fabrication constraintsshould be met:

(i) sharp irregularities at free edges due to theflame cutting process should be ground out;

(ii) no welding should be closer than 10mmfrom the edge of the unstiffened dooropening;

(iii) longitudinal edge stiffeners should becontinuous over their full extent.

(iv) Where shoulder joints are used, they shouldhave an angle of inclination to the axis ofthe column of between 12° and 35°. (SeeFigure 3 which shows a typical shoulderjoint)

5.14 Generally, when undertaking fatigue checksnominal stresses should be used based on nominalsection properties. The stress concentrationsinherent in the make-up of a welded joint (arising,for example, from the general joint geometry andthe weld shape) are generally taken into account inthe classification of the details. Otherwise thenominal stresses should be multiplied by stressconcentration factors derived from stress analysisof the joint or from published data.

5.15 In order to undertake a fatigue check it isnecessary to determine a loading spectra fromwind data appropriate to the site. In the absence ofsuch data, the fatigue loading provisions given inAnnex B may be adopted.

5.16 Classification may be derived by fatiguetesting of a sample of typical full-scale details inan independent testing laboratory and covering anappropriate stress range to enable a fatigue lifecurve to be derived. Sufficient tests should beundertaken to provide a design curve representingmean minus 2 standard deviations.

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5.17 In the absence of data on fatigue life curvesand loading spectra, the procedure set out in AnnexB shall be followed.

Determination of Shape Coefficients

5.18 Where wind tunnel tests are necessary forthe determination of shape coefficients forcolumns, brackets and lanterns, the testing shall becarried out in accordance with Annex D of thisStandard.

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Chapter 5Design

Figure 2 Door Openings

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February 2007

Chapter 5Design

α = angle of inclination to column axis

Figure 3 Typical Shoulder Joint

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February 2007

6. FIBRE REINFORCED POLYMER COMPOSITELIGHTING COLUMNS

Design

6.1 Loading. Design loads and moments shall bedetermined in accordance with BS EN 40-3-1 andBS EN 40-7 as implemented by this Standard.

6.2 The factor β for the dynamic behaviour ofthe FRPC column shall be determined by referenceto BS EN 40-7: Annex B: Figure B.1.

Verification of Structural Design

General

6.3 The structural design of FRPC columns shallbe verified either by calculations or by testing. Thetest results take precedence in all cases.

Calculations

6.4 Design calculations for FRPC columns shallbe in accordance with the requirementsBS EN 40-7.

6.5 The mechanical properties of the FRPmaterial to be used in the structural designcalculations shall be determined from tests usingflat sheet samples manufactured in the samemanner as that proposed for the productioncolumn. Flexural strength and the moduli in bothlongitudinal and transverse directions shall bedetermined together with the shear modulus andthe Poisson’s ratio, δ12. A statistical assessmentshall be made of the results to determine 95%confidence limits of the values to be used.

Use of Other Materials

6.6 All other materials incorporated in the FRPcolumns shall comply with the Specification andthe relevant parts of BS EN 40.

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Chapter 6Fibre Reinforced Polymer Composite Lighting Columns


Chapter 7Door Openings

7. DOOR OPENINGS

7.1 Where door openings are required, the sizesgiven in Table 2 should be specified when providinginformation for Appendix 13/1 of the Specification.

7.2 Alternative door openings selected from the sizesgiven in BS EN 40-2 may be used, provided they areshown to be adequate for the size of equipment to behoused and maintained, in the column.

7.3 Columns mounted on structures or insituations where there is a risk that a detached doorcould cause an accident if it fell on the area belowshall have their doors hinged or held captive by anapproved metal chain or strap which shall besufficiently robust, to support the door in severegale conditions.

7.4 Where the section containing the dooropening is steel or aluminium and circular orpolygonal with eight or more sides, designstrengths shall be calculated in accordance withBS EN 40-3-3, subject to the followingamendments:

Nominal column Type of doorheight (h) in metres c

5 and 6 single door

8, 10 and 12 single door

8, 10 and 12 extended single door

8, 10 and 12 double doors

February 2007

Table 2 Door

In clause 5.6.2.2, define:

YRLfEtEt07.02

2

3 +=φ but ≤ φ1; and

YRLfEtEt035.02

2

4 +=φ but ≤ φ2.

In all other cases the design strength shall becalculated from first principles. Alternatively, thedesign shall be based on the results of full-scaleload tests. In all such cases the procedures to beused shall be agreed between the designer, theclient and the Overseeing Organisation, see 4.2above.

Door opening for metal Door openings forolumns (height x width) concrete columns

(mm) (height x width) (mm)

500 x 100 680 x 95

600 x 115 680 x 130

- 900 x 130

500 x 120 -or 600 x 115 each

Opening Sizes

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February 2007

8. WALL MOUNTED BRACKETS

8.1 Wall mounted brackets shall be designed, inaccordance with the relevant requirements forcolumn brackets. The bracket shall be fixed to itssupport by means of a flange plate and anchoragewhich shall be designed in accordance withparagraph 10.9.

8.2 The wall on which the wall mountedbrackets are fixed shall be capable of carrying theadditional loads and other forces that may betransmitted by the bracket. The designer of thebracket shall provide the necessary loads for othersto assess the adequacy of the wall.

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Chapter 8Wall Mounted Brackets


Chapter 9Attachments

9. ATTACHMENTS

General Requirements

9.1 Minor structures, other than CCTV masts(see 9.6 to 9.8 below) and fixed traffic sign/signalposts (see EN 12899-1) shall be designed for theattachment given in paragraph 9.2. Attachmentsshall not be allowed on cantilever masts.

9.2 The attachment shall be taken as a sign,details of which shall be:

(i) The sign shall be taken as rectangular inelevation, with a surface area of 0.3 m2.

(ii) The eccentricity from the centre line of thecolumn to the centre of area of the sign shallbe taken as 300 mm.

(iii) The height above ground level at the columnto the centre of area of the sign shall betaken as 2500 mm.

(iv) The orientation of the sign shall be selectedto produce the most adverse effects for thedesign condition being considered.

9.3 The forces due to dead and wind loads onthe sign and bracket projecting from the columnshall be determined in accordance withBS EN 40-3-1. The shape coefficient of the signshall be taken as 1.8 unless derived fromBS EN 1991-1-4 for the specific shape and aspectratio of the sign.

9.4 Where larger signs, waste paper containers,flower baskets etc, are to be attached, the columnshall be designed to resist the additional loadings.Where appropriate the additional loadings shall becalculated in accordance with paragraph 9.3.

February 2007

9.5 Minor structures designed to carryattachments greater than those defined in 9.2 shallhave identifying manufacturer’s features or marksto enable them to be clearly and unambiguouslyidentified throughout their service life. The uniqueidentifying mark shall be listed as required byBD 62 (DMRB 3.2.1). All other requirements forthe identifying mark shall be as required in theSpecification. (See 4.1)

Attachments to CCTV Masts

9.6 CCTV masts shall not be designed forattachments other than CCTV cameras and theirassociated equipment unless otherwise specified.Where attachments are specified they shall beincorporated into the design of the CCTV masts inaccordance with the following provisions:

9.7 Where attachments are to be used, the mastshall be designed to resist the additional loading,which shall be described in Appendix 13 of theNotes for Guidance on the Specification(MCHW2). Where appropriate the additional deadand wind loads shall be calculated in accordancewith ILE TR7.

9.8 Where attachments are required the CCTVpole and the attachments shall be designed suchthat the operation of the CCTV camera is notimpeded. Similarly, access for installation,inspection or maintenance of an attachment shallnot interfere with the operation of the CCTVcamera. Where attachments are located below theoperating position of the camera, they shall bedesigned as demountable to allow the CCTVmounting to be raised and lowered.

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ECTION BETWEENND FOUNDATION

Chapter 10Flange Plate Connection Between Steel Structure and Foundation

10. FLANGE PLATE CONNSTEEL STRUCTURE A

General

10.1 Where foundations consist of reinforcedconcrete, the connection between the structure andits substructure shall be designed in accordancewith clauses 10.2 to 10.24 as appropriate.

10.2 A structure with a flange plate shall be fixedto the foundation or bridge deck by an attachmentsystem and anchorage which shall be capable ofproviding the required restraint. This will usuallytake the form of holding down bolts which connectwith an anchorage. Anchorages of expanding typeshall not be used. The attachment system shallallow the structure to be demounted, or, forlighting columns, be such that removal andreplacement of damaged lighting columns may bereadily achieved.

Note 1: The procedure given in 10.4 to 10.21 isbased on the flange plate and its connections beingdesigned to resist vehicle impact. For minorstructures that satisfy the requirements of clauses2.6(i), 2.6(ii) or 2.6(iii) design against vehicleimpact is not required. In such cases the flangeplate and its connections shall be designed for deadload and wind loads only. This shall be achievedby taking MR in the formulae following as thebending moment at the base of the structurederived from the ultimate factored dead load(permanent actions) and wind loads (variableactions).

Note 2: Where cantilever masts are located within4.5 metres of the edge of the carriageway (the edgeof the carriageway shall be as defined in BD 37(DMRB 1.3)) or within the central reserve, thedesign of attachment systems and anchorages shallbe such that removal and replacement of damagedcantilever masts may be readily achieved. Thisshall be achieved by providing an internallythreaded component in the anchorage to receivethe holding down bolts.

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February 2007

0.3 Typical arrangements are shown in Figure 5hich apply to both plates supported on beddingaterial and plates supported on levelling nuts only,ithout effective bedding.

10.4 When the weight of the structure is to becarried by nuts beneath the flange plate, theholding down bolts shall be designed to resist alladditional stresses arising from this constructiondetail, and protected against corrosion. When theweight of the structure is supported directlythrough the flange plate to the substructure, thespace should be packed with a suitable beddingmortar.

10.5 The diameter of circular flange plates shallnot be less than the pitch circle diameter of theholding down bolts plus 2.5 times the diameter ofthe bolts.

10.6 In the following procedure it is assumed thatbending about the v-v axis will be critical, which isthe case for columns on square flange plates withfour holding down bolts as shown in Figure 5. Themore general case is covered in Annex C.

10.7 The flange plate shall be capable ofdeveloping a moment of resistance about each axis,taken at the underside of the flange plate, at least1.2 times the theoretical ultimate moment capacity,MR (=Mup) of the actual structure calculated at baselevel in accordance with BS EN 40-3-3: Clause5.6.2.

10.8 The bending moment in the flange plateshall thus be taken as:

⎭⎬⎫

⎩⎨⎧

−=4a

20.63D5.0 1.2MM R (in N.m)

where D = 2R and R is the mean radius as definedin BS EN 40-3-3: Figure 3; and a is the boltspacing as shown in Figure 5.

10/1



10.9 The maximum bending in the flange plate,M, shall not exceed the plastic moment capacity ofthe flange plate, Mp. For a square flange plate witha centrally located hole not exceeding 0.3D indiameter (refer to Figure 5, detail B), Mp is givenby:

( )3

M

y2f

p x10γf

x 4

x t0.63Dc 2M −= in N.m)

where: γM = 1.15; c = the width of the flange plate(in mm); tf = the thickness of the flange plate (inmm); fy = the yield stress in the flange plate (in N/mm2); and D is as defined in 10.8. Where thecentrally located hole and the column base are thesame diameter (refer to Figure 5, Detail A), Mpshall be calculated in accordance with theprocedure given in Annex C.

10.10 Shear and bearing should not govern thedesign of the flange plate, provided edge distancesof the holding down bolts comply with thefollowing requirements. The minimum distancefrom the centre of the bolt hole to the edge of theplate shall not be less than 1.5d where d is thediameter of the hole.

In addition, for slotted holes the minimum distancefrom the axis of the slotted hole to the adjacentedge of the plate shall not be less than 1.5d and theminimum distance from the centre of the endradius of a slotted hole to the adjacent edge of theplate shall not be less than 1.5d.

Design of Welds

10.11 The connection between the column andthe flange plate shall be capable of developing thetheoretical ultimate moment of resistance of theactual column and the equivalent ultimate shearforce, both as derived in 10.7 above.

10.12 Welds shall be deemed to meet theserequirements provided the throat thickness of thetop weld is not less than k x t where: k = a valuebetween 1.0 and 1.5 depending on the type of welduse. For example k = 1.5 for the fillet welds ofdetail B in Figure 5 and for the outer fillet weld ofdetail A in Figure 5, k = 1.0 for a full penetrationbutt weld.

10/2

t = the wall thickness of the column at the flangeplate.

A more accurate procedure for the design of weldsis given in Annex C.

Design of Holding Down Bolts

10.13 The holding down bolts shall be capable ofdeveloping the theoretical ultimate momentcapacity of the actual column MR (=Mup) calculatedat the base level in accordance with BS EN 40-3-3:Clause 5.6.2 and an equivalent ultimate shearforce, FR (=2MR).

10.14 The tensile stress (σ) in holding down boltsmay be taken as:

( )2

et

3R N/mm

A a 210 x M 1.2

=σ

where: Aet = the tensile stress areas in the thread ofthe bolt obtained from the appropriate standard;a = the bolt spacing as shown in Figure 5.

10.15 The shear stress (τ ) in the bolts may betaken as:

( )2

eqb

R N/mm A nF 1.2

=τ

where: Aeq = the sectional area of the unthreadedshank of the bolt if the shear plane passes throughthe unthreaded part but taken as Aet if the shearplane passes through the threaded part; nb = totalnumber of bolts fixing the flange plate. Whereslotted holes are used nb shall not include bolts inholes where the slot aligns with the direction of theapplied shear force.

10.16 Bolts in tension and shear shall complywith:

Mq γ≤

⎪⎭

⎪⎬⎫

⎪⎩

⎪⎨⎧

⎟⎟⎠

⎞⎜⎜⎝

⎛ τ+⎟⎟

⎠

⎞⎜⎜⎝

⎛ σ 1f

2f

2/122

t

February 2007



where: γm is taken as 1.30; ft is the lesser of: (i) 0.7x minimum ultimate tensile stress; or (ii) either theyield stress or the stress at permanent set of 0.2%,as appropriate; fq = yield stress of bolts (factoredby 0.85 in the case of black bolts).

10.17 Due consideration of the capacity of thecomplete anchorage to resist the forces involved (1.5MR and 1.5 FR) should also be made with regard toembedment and pull out based on a 90° conerecommended in “Holding down systems for steelstanchions” CS/BCSA/Constrado, 1980.

Bearing Stresses Under Flange Plates

10.18 The bearing stress on the foundation mediumshould be derived on a basis compatible with theassumed bending mode v-v, on either a plastic or elasticbasis as required. On a plastic basis, the maximumbearing stress for bending about v-v may be taken as:

)/(0.7R)0.5c(aR) - c (0.7 0.7

10 x M 3 22

3R mmN

++

where MR, c, a and R are all as defined above.

10.19 The bearing stresses in any bedding mortarunder the flange plates shall not exceed 20 N/mm2.The maximum bearing stresses on the concreteunder a flange plate shall be in accordance with therequirements of BS EN 1992.

10.20 The requirements for foundations on masonryshall be agreed with the Overseeing Organisation.

10.21 For bases founded on steel bridge decks a morethorough analysis is required and is outside the scope ofthis standard.

Design of Anchorages to Bolts

10.22 This is dependent on the medium in whichthe anchorages are made. The anchorages shall bedesigned to cater for a maximum tensile force, TA,and associated shear, FA, as follows:

February 2007

TA = 1.25 σ Aet (in N); andFA = 1.25 τ Aeq (in N).

where σ, τ, Aet and Aeq are all as derived above.

The capacity of the anchorage shall be derived inaccordance with Section 11 (and relevant parts ofEN 1997.)

10.23 The supporting structure shall be designedto resist the above anchorage loads withoutdamage. The tensile strength of the concreteshould be ignored in the calculations. The concretein the foundation or bridge component to which acolumn is fixed shall be reinforced against burstingassociated with the above internal forces generatedby the holding down bolts/anchorage system.

Use of Levelling Nuts and Slotted Holes

10.24 Where levelling nuts (or other system ofpermanent packers) are being used withouteffective bedding it shall be assumed that all thebearing stresses are transferred to the levellingnuts. The nuts and washers on both sides of theflange plate thus need to be sufficiently oversizedto prevent any localised plate failure due toconcentration of stresses. This may be achieved byusing washers complying with ISO 7093, providedthe hole or width of the slotted hole does notexceed do + 4mm where do is the diameter of theholding down bolts.

10.25 For slotted holes, which provide flangeplate rotations of up to ± 5° as shown in Figure 6,washers of adequate thickness shall be provided onboth sides of the flange plate to transfer load intothe holding down bolts. Washers complying withISO 7093 may be used provided the width of theslotted holes does not exceed do + 6mm.

10.26 Where hole or slotted clearances aregreater than the above values, consideration shouldbe given to the use of special plate washers. Wherelevelling nuts are used the nut and washer sizeshall be the same above and below the flange plate.

10/3


NOT

10/4


Figure 5 Typical Arrangement of Flange Plate

E: 1. Details A and B are typical only and may be used with circular or octagonal columns if required.

2. R = mean radius as defined in BS EN 40-3-3 (Figure 3).

3. '*': Radius of centrally located hole shall not exceed 0.3R.

February 2007


February 2007


Figure 6 Slotted Holes Arrangement

10/5


Chapter 11Foundations

11. FOUNDATIONS

Foundations – General

11.1 Foundations shall either consist of:

(i) reinforced concrete, designed inaccordance with paragraphs 11.10 to 11.16as appropriate; or

(ii) planted columns and posts, designed inaccordance with paragraphs 11.3 to 11.9 asappropriate;

(iii) planted prefabricated concrete or metalcolumns designed in accordance with 11.3to 11.17 as appropriate.

Note: The design rules given in paragraphs 11.3 to11.12 do not apply to foundations on slopes, wherestability of the ground needs to be taken intoaccount. In such instances, specialist geotechnicaladvice shall be sought.

Note: Planted columns shall not be used for CCTVmasts.

11.2 Alternative forms of foundation may beused subject to the approval of the OverseeingOrganisation.

Foundations for Planted Columns, Posts andPrefabricated Foundations

Planting Depth:

11.3 Where a minor structure is to be planteddirectly in the ground, the planting depth shall beselected from Table 7 of BS EN 40-2 related to theoverall height of the structure. In the case ofprefabricated foundations the planting depth andeffective diameter shall be selected to ensurecompliance with the calculation method providedbelow.

Note: For traffic sign/signal posts, the valuesappropriate to the central column of this table maybe used. Where the height is less than 2 m a depthof 600mm may be adopted, provided therequirements of paragraph 11.6 are satisfied.

February 2007

To check the adequacy of the selected plantingdepth, taking account of the ground conditions atthe site, the calculation procedure given belowshall be adopted.

11.4 The greatest destabilising moment, MDS ,arising from application of the un-factored designloads (e.g. wind load or dynamic load from snowclearance) to the minor structure and its supportsshould either be calculated or obtained from thedesigner. The destabilising moment shall becalculated about a fulcrum point located at 1/√2 ofthe planting depth below ground.

The destabilising moment shall be multiplied by amodel factor γs;d of 1.25.

11.5 The ground resistance moment Mg, shouldbe calculated using the following formula:

10P x DG x M

3

g =

Where:

G is a factor dependent on the ground in whichthe column is planted (in kN/m2 per m).Refer to Table 3 for typical values of G.

D is the minimum diameter (or minimumdistance across flats for multi-sidedsections) of the traffic sign in the ground(in m).

P is the planting depth.

11.6 The planting depth is satisfactory ifMg > γs;d x MDS .

11.7 If this criterion is not satisfied then theplanting depth shall be increased and/or theeffective diameter of the minor structure shall beincreased. The latter can be achieved bybackfilling the excavation hole with mass concreteor an acceptable fill material (refer to ‘Back-filling’ below); the effective diameter of the trafficsign/signal post may then be taken as the minimumdiameter of the excavation hole.

11/1


G (kN/m2 Soilper m) Impact

Factor ksi

well-graded fine 630 0.2

l drained sandy 390 0.3

stand on the surface.

containing a large 230 0.5.

and soil impact factor ksi


Quality of soil

Good: Compact, well-graded sand and gravel, hard clay,and coarse sand, decomposed granite rock and soil.Good soils drain well.

Average: Compact fine sand, medium clay, compact welloam, loose coarse sand and gravels.Average soils drain sufficiently well that water does not

Poor: Soft clay, clay loam, poorly compacted sand, claysamount of silt and vegetable matter, and made-up ground

Where the Quality is unknown, it shall be taken as Poor.

Table 3 Ground Factor G

Back-filling:

11.8 The calculation of ground resistancemoment Mg, is based on the excavated hole intowhich the minor structure is planted being back-filled with the excavated material or material ofbetter quality.

The following shall be specified to the installer:

(a) all back-filling material shall be placed in150mm thick layers and well compacted;where the manufacturer proposes to useprecast foundations, the backfillingmaterial and procedure shall be described;

(b) during compaction, care shall be taken toensure that the corrosion protection systemfor the minor structure is not damaged;

(c) where the excavated hole is back-filledwith concrete, the concrete shall extendfrom the base of the minor structure toground level; and

(d) where paving or bituminous surfacing is tobe applied around the minor structure, thetop level of the concrete may be reduced bythe thickness of the surfacing.

11/2
February 2007
11.9 Planted columns shall incorporate amechanism which prevents rotation of the columnor post in the ground under wind loading wheresignificant torsional loading can arise. The designof planted columns shall take account of settlementand its effect on clearances if relevant.

Foundation for Columns with Flange Plates

11.10 The design principles of foundations shallbe based on the design methods given in BS EN1997-1. The foundation shall be designed to resistthe foundation design moment Mfd and foundationdesign shear force Ffd derived as follows.

Mfd shall be the greater of the impact moment Miand the moment obtained from BS EN 40-3-1,BS EN 12899-1 or ILE TR7 as appropriate,factored by the appropriate partial factor on load,γF (refer to BS EN 1997), for the failure modeunder consideration.

Ffd shall be the greater of the impact shear force Fiand the horizontal force obtained fromBS EN 40-3-1, BS EN 12899-1 or ILE TR7 asappropriate, factored by the appropriate partialfactor on load, γF (refer to BS EN 1997), for thefailure mode under consideration.



For destabilizing actions (e.g. overturningmoment) γF;dst shall be taken as at least 1.5. Forstabilizing actions (e.g. gravity resistance tooverturning) γG;stb shall be taken as 0.9 or less.

Mi and Fi are derived as follows:

Mi = ksi MRFi = ksi FR

where the ultimate moment of resistance of theactual column at the base level, MR, is calculatedin accordance with BS EN 40-3-3: clause 5.6.2together with an equivalent ultimate shear force,FR. An upper bound to the equivalent ultimateshear force may be taken as:

upup

R 2M0.5

MF == . Refer to BS EN 40-3-3

for the calculation of Mp.

This assumes that the point of impact is 0.5mabove the top of the foundation.

The soil impact factor, ksi is given in Table 3 basedon the three types of soil listed therein.

Foundations for Cantilever Masts with FlangePlates

11.11 When cantilever masts are positioned in locationsas given in paragraph 2.6 the following procedure maybe used.

11.12 Foundations shall consist of reinforcedconcrete blocks. The structural concrete shall bedesigned in accordance with BS EN 1992.

11.13 The design loads for the foundation shallbe the nominal loads and nominal wind loadingapplied by the cantilever mast when designed inaccordance with this Standard, factored by theappropriate partial factors on load, γF (refer toBS EN 1997).

11.14 The design of the foundation shall be basedon the design methods given in BS EN 1997, usingthe partial factors on actions given in 11.10 above.

1oaf

TmsbfB

1Asl

February 2007

1.15 Because of the difference in the behaviourf the cantilever mast and its foundation, in thebsence of more accurate information, theollowing may be assumed:

he basic wind load transferred from the cantileverast to the substructure at the top of the

ubstructure reduces to 1/β of this value at theottom of the substructure and foundation. β is theactor for dynamic behaviour given inS EN 40-3-1 : Clause 3.2.4.

1.16 Unless otherwise agreed with the Technicalpproval Authority, the criteria given in 11.10

hall apply when cantilever masts are positioned inocations other than those given in paragraph 2.6.

11/3


Chapter 12References

12. REFERENCES

12.1 British Standards Institution

BS EN 40: Lighting Columns:

Part 1: Definitions and terms

Part 2: General requirements and dimensions

Part 3-1: Design and verification – Specificationfor characteristic loads

Part 3-2: Design and verification – Verificationby testing

Part 3-3: Design and verification – Verificationby calculation

Part 4: Requirements for reinforced andprestressed concrete lighting columns

Part 5: Requirements for steel lighting columns

Part 6: Requirements for aluminium lightingcolumns

Part 7: Requirements for fibre reinforced polymercomposite lighting columns

BS EN 1991-1-4: Actions on structures. Part 1.4 WindActions

BS 8004: Code of Practice for Foundations

BS EN 1992-1: Eurocode 2 Design of ConcreteStructures

BS EN 1994-1: Eurocode 5 Design of masonrystructures

BS EN 1993-1-1: Eurocode 3: Design of SteelStructures: Part 1.1: General Rules and Rules forBuildings

BS EN 12899-1: Fixed, vertical road traffic signs –Part 1: Fixed signs

PD 6547: Guidance on the use of BS EN 40-3-1 andBS EN 40-3-3, BSI

February 2007

12.2 Design Manual for Roads and Bridges

Volume 1: Section 1 Approval Procedures

Volume 1: Section 3 General Design

12.3 Manual of Contract Documents for HighwayWorks. (MCHW)

Volume 1: Specification for Highway Works(MCHW 1)

Volume 2: Notes for Guidance on the Specification forHighway Works (MCHW 2)

12.4 International Standards Organisation

ISO 7093 – Plain washers – Large series – Productgrades A and C, First edition – 1983-09-15

12.5 Other Publications

Holding down systems for steel stanchions – Publishedby The Concrete Society, The British ConstructionalSteelwork Association (BCSA) and ConstructionalSteel Research and Development Organisation(Constrado) – October 1980.

The Institution of Lighting Engineers Technical ReportNumber 7, High Masts for Lighting and CCTV, 2000Edition, sections 1 and 2 (ILE TR7).

12/1


February 2007 13/1

13. ENQUIRIES

All technical enquiries or comments on this Standard should be sent in writing as appropriate to:

Chief Highway EngineerThe Highways Agency123 Buckingham Palace RoadLondon G CLARKESW1W 9HA Chief Highway Engineer

Chief Road EngineerTransport ScotlandTrunk Roads and Professional Services8th Floor, Buchanan House58 Port Dundas RoadGlasgow J HOWISONG4 0HF Chief Road Engineer

Chief Highway EngineerTransport WalesWelsh Assembly GovernmentCathays Parks M J A PARKERCardiff Chief Highway EngineerCF10 3NQ Transport Wales

Director of Engineering (Acting)The Department for Regional DevelopmentRoads ServiceClarence Court10-18 Adelaide Street R J M CAIRNSBelfast BT2 8GB Director of Engineering (Acting)

Chapter 13Enquiries


February 2007

ANNEX A LIMIT STATES FOR CANTILEVER MASTS

Partial Factor on Load γF

Limit State Limit State Fabricated Superimposed Wind Load Buffeting fromDescription Type Metal Dead Dead Load High Vehicles

Load

Strength (STR) ULS 1.05 1.50 1.40 -

Fatigue SLS 1.00 1.20 1.00 1.00

Deflection SLS 1.00 1.20 1.00 0.50

Table A1 Limit States and Partial Factors

Element and Position Direction of Deformation Limiting

Top of Post Horizontal ∆x1 or ∆y 1/100 of height of post

Tip of Cantilever Horizontal ∆x2 1/100 of outreach plus height of post

Tip of Cantilever Vertical ∆z 1/100 of outreach plus height of post

Table A2 Limiting Structural Deformations of Cantilever Masts [See Figure 1]

A/1

Annex ALimit States for Cantilever Masts


S OF STEELD GUIDANCE FORATION

Annex BFatigue Checks of Steel Structures and Guidance for Weld Classification

ANNEX B FATIGUE CHECKSTRUCTURES ANWELD CLASSIFIC

B.1 When undertaking fatigue checks inaccordance with the following rules, nominalstresses shall be used based on nominal sectionproperties. The stress concentrations inherent inthe make-up of a welded joint (arising, forexample, from the general joint geometry and theweld shape) have been taken into account in theclassification of the details.

Where indicated, however, the nominal stressesshall be multiplied by stress concentration factors,indicative values of which are provided in therelevant clause.

B.2 For reinforcement at door openings thegeometric constraints set out in 5.13 and B.8 shallbe met, and stress ranges around door openingsneed not be calculated. However if theseconstraints are not met then the requirements ofB.3 or B.4 shall be followed, as appropriate.

B.3 For minor structures other than cantilevermasts for traffic signals and/or speed cameras thatproject over the carriageway, only fatigue due towind gust loading shall be considered and therequirements of B5 to B10 shall be satisfied.

B.4 For cantilever masts for traffic signals and/or speed cameras that project over the carriagewaythe fatigue effects from wind gust loading and highvehicle buffeting shall be combined and therequirements of B11 to B13 shall be satisfied.

Fatigue Due to Gust Wind Loading

B.5 A check on fatigue at and adjacent to eachwelded section, including the ends ofreinforcement at door openings where relevant,shall be undertaken using a stress range σr, givenby:

⎟⎟⎠

⎞⎜⎜⎝

⎛⎟⎟⎠

⎞⎜⎜⎝

⎛−=

stat

vssr c

cβ110.25σσ

February 2007

where:

σs is the stress calculated at this position for thedesign forces and moments specified inSection 4 of BS EN 40-3-1;

β is the dynamic response factor (Clause 3.2.4of BS EN 40-3-1);

cstat is the average shape coefficient for the tophalf of the column as used for the staticanalysis and given in Figure 3 ofBS EN 40-3-1;

cvs is 1.2 for circular sections;

is 1.3 for octagonal sections with r/D >0.075;

is 1.45 for octagonal sections with r/D <0.075;

r is the radius of the corner;

D is the distance across the flats.

B.6 This stress range shall be less than thatobtained from B.7, appropriate to the class ofdetail being considered and for a number of cyclesn1 given by:

n1 = 106NfL

where:

Nf is the frequency of vibration of the column(Hz);

L is the design life of the structure (years).

B/1



B.7 For a design life of 25 years, the maximumallowable stress range is given in Figure B1.1(a) orFigure B1.1(b) appropriate to the class of detail underconsideration and dependent on the frequency Nf (Hz).These curves are for design and incorporate a partialfactor on fatigue strength. The method of defining theS-N curves given in Figure B1.1(a) and Figure B1.1(b)is by two numbers joined by a hyphen. The first numberis the reference strength at 2x106 cycles and the secondis the m value which is a constant applicable to valuesof n1 up to 5x106 cycles. This is the procedure adoptedfor defining fatigue strength in BS EN 1993-1-9. Thebasis of the curves in Figures B1.1(a) and B1.1(b) isgiven in B.8.

Note: For a design life of L years Figure B1.1 may beused by adopting an effective frequency Nfe as thehorizontal scale given by:

25L x N N ffe =

B.8 Fatigue is critically dependent ongeometrical configurations and fabrication.

The following geometric and fabricationconstraints on cross sections of steel lightingcolumns shall be satisfied, in order to use theclasses of details as provided in B.9.

Flange Plates

(a) The column/flange plate weld 1A, 2/1 and2/2 shown in Figures B.2, B.3 and B.4 shallhave a throat size K times greater than thethickness of the adjacent shaft material,where K is given by:

Weld K

1A 1.10

2/1 1.25

2/2 1.25*

*Or use full penetration butt weld

(b) The thickness of the base material tb shall benot less than the thickness of the adjacentshaft material, ts.

B.inccoB.prtesrepUKclaanprwetreothan

B/2

Shoulder Joints

(c) Welded Shoulder joints as shown in FiguresB.5, B.6 and B.7 shall have an angle ofinclination to the axis of the columns, α,between the following limits:

12°< α < 35°

(d) The shoulder joint weld A as shown infigures B5, B6 and B7 shall have a throatsize 10% greater than the thickness of theadjacent shaft material, ts.

(e) To ensure that weld detail 6 (see Figure B.8)behaves as intended the lapped length shallbe at least 1.5 times the diameter of thelapped shaft. Each section shall begalvanised to avoid the risk of prematurefailure due to rusting.

Door Openings

(f) Stiffened and unstiffened door openingsshall comply with the constraints shown inFigure B.9. In addition the followingfabrication constraints shall be met:

i. sharp irregularities at free edges dueto the flame cutting process shall beground out;

ii. no welding shall be closer than 10mmfrom the edge of the door unstiffenedopening.

Longitudinal edge stiffeners shall be continuousover their full extent.

9 Guidance on classes of typical weld detailsorporating stress concentration factors, Kf, which

mply with the constraints of B.6 are given in Figures2 to B.9 for welds made using normal commercialactice, e.g. manual welds without NDT or otherting. This guidance was based on fatigue tests of aresentative number of details provided by a range of lighting column manufacturers. However

ssification is critically dependent on welding qualityd fabrication methods, and hence the informationovided is for guidance only. Closer control of thelding and fabrication process and/or post-weldatment may improve the weld classification. Forer welded details specialist advice should be sought

d reference made to BS EN 1993-1-9.

February 2007



B.10 Figures B1.1(a) and (b), the fatigue life curves,are based on:

(a) No. of cycles to failure N = 2 x 106

m

⎟⎟⎠

⎞⎜⎜⎝

⎛

r

o

σσ

where σo = details category(50, … 120 …)

m = slope of curve (3 for FigureB1.1(a) and 4 for Figure B1.1(b))

σR = stress range

(b) The number of cycles relate to the frequency bythe equation in B.4:

N = 106 Nf L

(c) Thus for a design life of L of 25 years:

N = 25x106 Nf

(d) Thus, the relationship between σR and Nf (theplots of Figures B1.1(a) and B1.1 (b)) is:

f6

m

R

o6 N 10 x 25σσ

10 x 2 =⎟⎟⎠

⎞⎜⎜⎝

⎛

i.e. m

Rσoσ

1008Nf ⎟

⎟

⎠

⎞

⎜⎜

⎝

⎛=

e.g. for class detail 120: 4

σo = 120

m = 4

4

Rf σ

120100

8N ⎟⎟⎠

⎞⎜⎜⎝

⎛=

σR 100 90 80 70 60 50

Nf 0.166 0.253 0.405 0.691 1.280 2.650

February 2007

Fatigue from High Vehicle Buffeting

B.11 The stress range σr2i in any part of thestructure for fatigue due to high vehicle buffetingshall be calculated by applying:

(i) a pressure of Pd to the portion of thecantilever arm and any attachments abovethe carriageway vertically downwards; and

(ii) a pressure of Pd to the portion of thecantilever arm and any attachments abovethe carriageway horizontally against thedirection of the traffic.

The pressure Pd shall be calculated as:

Pd = 600h-0.25 – 400 (in N/m2)

Where h is either:

(i) The distance from the top of the high sidedvehicle to the underside of any horizontalsurface; or

(ii) The distance from the top of the high sidedvehicle to the centre of pressure of anyvertical surface.

A typical high sided vehicle height of 4.2 metresshall be used. (see note 3, clause B.12). Theformula for Pd applies for a value of up to h = 5m.

Applied loads shall be calculated as the product ofthe appropriate pressure and projected area. Partialload factor γfL shall be taken as 1.0.

Fatigue Damage Assessment

B.12 Fatigue damage shall be assessed as follows:

(i) For fatigue due to gust wind loading

The number of cycles, n1, shall be calculatedfrom B.6

The corresponding number of cycles to failure, N1shall be given by:

m

r1

o61 σ

σ10 x 2N ⎟⎟

⎠

⎞⎜⎜⎝

⎛=

B/3



(ii) For fatigue due to high vehicle buffeting:

The number of cycles for each lane in acarriageway, n2i, shall be given by:

n2i = 1.6 x 107.L.Fi

The corresponding number of cycles to failure, N2i,is given by:

m

r2i

o62i σ

σ10 x 2N ⎟⎟

⎠

⎞⎜⎜⎝

⎛=

Where:

L is the design life of the structure (years)

σo is the details category (50, … 120 …), (seeparagraph 5.15 and, for relevant details,from B.8);

Fi is the lane allocation factor (see Table B1);and

m is the slope of curve (see paragraph B.7).

Lane Allocation Factors, Fi

Type of Lane 1 Lane 2 Lane 3 Lane 4carriageway

D2M 0.7 0.3 - -

D3M 0.6 0.4 0.0 -

D4M 0.4 0.4 0.2 0.0

Table B1 Lane Allocation Factors

(iii) The fatigue effects from wind gust loadingand high vehicle buffeting shall becombined and shall satisfy the followingcriterion:

12

2

1

1 ≤+∑T

i i

i

Nn

Nn

where T is the number of lanes directly beneath thecantilever arm.

B/4

Notes:

The number of cycles for high vehicle buffeting isbased on:

1. The passage of 7,000 such vehicles per dayon each carriageway. Where flows are lessthan this average, then the values of n2ishould be reduced in proportion. Flows ofhigh sided vehicles shall be determined bytraffic survey. The total number of highsided vehicles shall not be reduced below avalue of 1,000 for design purposes.

2. A total logarithmic decrement of damping of0.03; where damping is less than this valuethen specialist advice should be sought.

Furthermore:

3. A high sided vehicle height of 4.2 metres hasbeen adopted for calculating the pressure Pd,as a representative height of such vehiclescurrently in use on UK highways; where aparticular site has a significantly higheraverage vehicle height then this should beused instead.

4. The design pressure, Pd, assumes that themaximum speed of the high sided vehicle islimited to 60mph. Where regulations permithigher maximum speeds then specialistadvice should be sought.

B.13 Checks on fatigue shall be undertaken at thefollowing positions:

(i) at and adjacent to each welded section; and

(ii) the end of the reinforcement at dooropenings.

February 2007


Febr


Note: For basis of curves see B.9

Figure B1.1(a) Fatigue of Column Stress Range Limit for Classof Weld Detail Based on a 25 Year Design Life Requirement (m=3)

uary 2007 B/5



B

Note: For basis of curves see B.9

Figure B1.1(b) Fatigue of Column Stress Range Limit for Classof Weld Detail Based on a 25 Year Design Life Requirement (m=4)

February 2007/6



Weld Section to be checked Class of Parent Kf = Kt Kb KhMetal

(1) Provided weld 1A is designed for transfer of the total load and weld 1B is for sealing only. Otherwise adetailed stress analysis shall be undertaken and the resulting stress concentration factors used.

(2) No fatigue check need be undertaken on the weld throat provided the criteria of B.8 are met. The parentmetal shall still be checked.

Figure B.2 Weld Detail Type 1

t2Kt =

1A1B A-A

⎟⎟⎠

⎞⎜⎜⎝

⎛=

5t

K fb

30Kf - 4 (1) 3

but < 0.33 and > 1.45

Kh = 1.0

February 2007 B/7




Note: No fatigue check need be undertaken on the weld throat provided the criteria of B.8 are met. The parentmetal shall still be checked.

Figure B.3 Weld Detail Type 2/1

t2Kt =

A-A⎟⎟⎠

⎞⎜⎜⎝

⎛=

5t

K fb

30Kf - 43

but < 0.33 and > 1.45

Kh = 2 / [1 + (dh / (ds - 2t))3]

2/1

February 2007B/8




Note: No fatigue check need be undertaken on the weld throat provided the criteria of B.8 are met. The parentmetal shall still be checked.

Figure B.4 Weld Detail Type 2/2

t2Kt =

A-A⎟⎟⎠

⎞⎜⎜⎝

⎛=

5t

K fb

30Kf - 43

but < 0.33 and > 1.45

( )( )[ ]3shh 2td/d12/K −+=

2/2

February 2007 B/9



Weld Section to be checked ClassParent Metal Weld Throat


3A A-A 90 – 4 (1) See (2)

3B No check necessary if criteria of B/8 are met

3C C-C

(1) Incorporates stress concentration factor, take Kf = 1.0.(2) No fatigue check need be undertaken on the weld throat provided the criteria of B.8 are met. The

parent metal shall still be checked.

90 – 4 (1) See (2)



4 A/A 71 – 4 (1) See (2)

(1) Incorporates stress concentration factor, take Kf = 1.0.(2) No fatigue check need be undertaken on the weld throat provided the criteria of B.8 are met. The


February 2007B/10





5A A-A 90 – 4 (1) See (2)

5B No check necessary if criteria of B/8 are met 120 – 4 See (2)

C-C. Plugs not ground smooth 90 – 4 -5C

C-C. Plugs ground smooth 120 – 4 -

(1) Incorporates stress concentration factor. Ttake Kf = 1.0.(2) No fatigue check need be undertaken on the weld throat provided the criteria of B.8 are met. The


February 2007 B/11



6 A-A N / A (1) 71 - 4 See (2)

(1) Assumes tight fit between tubes for load transfer by shear.(2) No fatigue check need be undertaken on the weld throat. The parent metal shall still be checked.(3) Refer to B.8(e) regarding the detailing of this joint.

Weld Section to be checked ClassUpper Tube Lower Tube Weld Throat

Parent Metal Parent Metal


February 2007B/12



Weld/Detail Detail to be checked Class (1)

7 Intermediate weld 80 - 3

8 Intermediate weld 71 - 3

9 End Weld 50 - 3

10 Flame cut edge 112 - 4

(1) No fatigue stress calculations need be undertaken provided the geometric and fabrication constraints ofB.8 have been met. Otherwise the above classification should be adopted in conjunction with a detailedstress analysis incorporating appropriate stress concentration factors.

Figure B.9 Weld Detail Types 7 to 10

February 2007 B/13


N OF FLANGE PLATES

Annex CDetailed Design of Flange Plates

ANNEX C DETAILED DESIG

C.1 General

C.1.1 The procedure given in Chapter 10 for thedesign of flange plates assumes circular or octagonalcolumns connected to square flange plates with acentrally located hole not exceeding 0.30D in diameterand supported by four holding down boltssymmetrically disposed. The following generalprocedure may be used for square plates with centrallylocated holes either not exceeding 0.30D in diameter, orof diameter equal to that of the column (see FigureC.1). This procedure provides design criteria for thewelds, the plate, the holding down bolts and the bearingstresses.

C.1.2 In addition a conservative assumption hasbeen made for the position of the axis of bending. Theprocedure given herein provides a more accuratederivation of the maximum bending moment on theplate to be used in design.

C.1.3 For flange plates not complying with theconstraints of C.1.1 other suitable design methods, orfull scale load tests may be adopted, subject to theapproval of the Overseeing Organisation.

C.2 Derivation of Weld Stresses

C.2.1 The connection between the column andflange plate shall be capable of developing the ultimatemoment of resistance, MR, as derived fromBS EN 40-3-3 and the equivalent shear force, FR. Theconnection may be achieved by welds of leg length, twas shown in Figure 5, detail A or B.

NOTE: In the case of detail B in particular, the lengthof fillet weld, tw, required may need to be considerablyin excess of the wall thickness, t, in order to satisfythese requirements. Alternatively, a full penetration buttweld may be used which will automatically satisfythese requirements.

C.2.2 The stress in the fillet welds due to moment ofresistance MR may be taken as:

( )( )2

w2

3R

1 N/mmin t0.7πR

10Mτ

⋅=

Tsh

τ

w

C

Ce

w

(Wmsic

February 2007

he shear stress in the fillet welds due to the equivalentear force FR may be taken as:

( ) ( ) ( )2

w

R

w

R2 N/mmin

0.7tπRM

0.7tR2πF

τ ==

R the resultant weld stress shall be taken as:

( ) ( ) )(N/mm 1R

10000.7tπR

Mτττ 22

w

R1/222

21R +⎟

⎠⎞

⎜⎝⎛=+=

here R = mean radius of cross section (in mm);

tw = fillet weld leg length (in mm).

.3 Capacity of Welds

.3.1 The stress in the fillet welds, τR, shall notxceed the weld capacity τD given by:

( ) ( )2

m

yD N/mmin

32γ455fk

τ+

=

here fy is the yield stress of the column section(fs) or the flange plate (ff) whichever isthe lesser;

γm is taken as 1.20;

k = 0.9 for side fillets where the weld issubject to longitudinal shear; or

1.4 for end fillets in end connectionswhere the weld is subject to transverseshear; or

1.0 for all other welds.

here inner fillets and outer fillets are used together kay be aggregated, e.g. k = 2.8 for detail A in Figure 5nce both are effectively end fillets for an endonnection.)

C/1



C.4 Design of Flange Plates

C.4.1 Derivation of Bending Moments in FlangePlates

C.4.1.1 The flange plate shall be designed to resist atleast the effect of 1.2 MR at the base of the columnwhere MR is as derived from BS EN 40-3-3, and shallbe checked about bending parallel to one side (axis u-u)and on the diagonal (axis v-v) see Figure C.1.

C.4.1.2 The maximum bending moment on the flangeplate axes u-u and v-v for plates with effective beddingor supported on levelling nuts only may be taken as:

( )inN.ma

2Rα1M 0.6M Ruu ⎥⎦⎤

⎢⎣⎡ −=−

( )inN.m2a

2Rα1M 0.6M Rvv ⎥⎦

⎤⎢⎣

⎡−=−

where R = mean radius of the column crosssection (in mm);

a = spacing of the bolts (in mm);

and α relates to the position considered for maximumbending in the plate. In lieu of more thorough analysisα may be based on the centroid of the welds on thetensile side, i.e. α may be taken as 0.63.

C.4.2 Bending Capacity of Flange Plate

C.4.2.1 The maximum moment in the flange plate, M,shall not exceed the plastic moment capacity of theflange plate, Mp. For a square flange plate where thecentrally located hole is the same diameter as thecolumn base (refer to Figure C.1, detail A) Mp is givenby:

( ) ( ) axis;u -ufor N.min 10γ

f4t

α12RcM 3m

f2f2

p −−=

and

( ) ( ) axis; v-for v N.min 10γf

4t

)-1(2R2cM3

m

f2f2

p α+α−=

w

C

C

Cm

w

Nt+w

Tda

C

C/2

here γm is taken as 1.15;

c = the width of the flange plate (in mm);

tf = the thickness of the flange plate (inmm);

ff = the yield stress of the flange plate (inN/mm2).

.5 Design of Holding Down Bolts

.5.1 Derivation of Stresses in Bolts

.5.1.1 The tensile stress in the holding down boltsay be taken as:

)(N/mmA a n

10 x 1.2Mσ 2

ett

3R=

here nt is related to the number of bolts resistingtension and the assumed axis of bending andmay be taken as:

0.5nb for bending about axis u-u; seeFigure C.1; or

0.25nb for bending about axis v-v; seeFigure C.1;

Aet = the tensile stress area in the thread of thebolt obtained from the appropriate standard;

a = the bolt spacing;

nb = total number of bolts fixingthe flange plate.

OTE: In general (nt x a) should not be taken as greaterhan (a + αR + 0.5c) for axis u-u, nor greater than 0.7(a 0.7αR + 0.5c) for axis v-v to ensure compatibilityith the assumed mode of bending in 5 above.

he shear stress in the bolts may be taken to be thaterived in 10.14, combined shear and tension in 10.15nd capacity of the anchorage from 10.16

.6 Check on Bearing Stress Below the FlangePlate

C.6.1 The bearing stress given in 10.17 assumesbending about the v-v axis. In general it will benecessary to derive the bearing stress on the foundation

February 2007



medium for both the assumed bending modes u-u andvv, on either a plastic or elastic basis as required. Themaximum calculated bearing stress shall not exceed thevalue determined in accordance with 10.18.

C.6.2 On a plastic basis, the maximum bearingstress for bending about u-u may be taken as:

)(N/mmc) 0.5 R α 0.5 a R)(0.75 α - c c(0.5

10 x M 3 23

R

++

C.6.3 On a plastic basis, the maximum bearingstress for bending about v-v may be taken as:

)(N/mmR) α 0.7 0.5c (aR) α - c 0.7(0.7

10 x M 3 22

3R

++

where MR, c, a, R and α are all as defined in C.4.1above.

February 2007 C/3


NOTE:

C/4


Figure C.1 Typical Arrangement of Flange Plate

1. Details A and B are typical only and may be used with circular or octagonal columns if required.

2. R = mean radius as defined in BS EN 40-3-3 (Figure 3).

3. '*': Radius of centrally located hole shall not exceed 0.3R.

February 2007


N OF SHAPEY TESTING

Annex DDetermination of Shape Coefficients by Testing

ANNEX D DETERMINATIOCOEFFICIENTS B

D.1 Shape Coefficients for Columns

General

D.1.1 Properly conducted wind tunnel tests oncolumns and brackets shall only be undertaken whenshape coefficients are not available from BS EN 40-3-1or from recognised International Standards. Adoption ofvalues from these standards or from wind tunnel testsshall be agreed with the Technical Approval Authority.Particular care should be taken to ensure that the valuesof shape coefficients relate to cross-sections ofmembers of infinite length.

D.1.2 Wind tunnel tests to establish shapecoefficients should be carried out using full scalespecimens which accurately represent the finalproposed column. The forces on the specimen shall bemeasured in the direction of the air flow and thedirection normal to the air flow.

D.1.3 Previous wind tunnel tests have indicated thatsmall angular rotations of specimens can causeconsiderable differences in shape coefficients. Thespecimens shall therefore be turned in the wind tunneland measurements taken at angular increments. In theregion of each shape coefficient the measurements shallbe reduced to approximately 1° of rotation.Comparisons shall be made with the values of similarsections given in recognized International Standards aspart of the adoption and agreement procedure with theTechnical Approval Authority set out in 4.

D.2 Shape Coefficients for Lanterns, Cameras,Signs and Brackets

D.2.1 The shape and lift coefficients for lanterns,cameras and signs may be determined from wind tunneltests as required by BS EN 40-3-1. These tests shall becarried out on a full scale shape of the element in atunnel sufficiently large to reduce side effects to aninsignificant level. The surface condition of thespecimen shall accurately represent that of theproduction version. Where optional attachments will bemade to the element, eg. photo-electric control units,gear component extensions etc, these shall be includedin the test specimen.

Dbnlrof

Diltmi1ptc±

February 2007

.2.2 When carrying out wind tunnel test, forcesoth in the direction of the air flow and in the directionormal to the air flow shall be measured, as shape andift coefficients are required for all the directionsequired in D.2.3. All shape coefficients shall be basedn the projected area of the element normal to the airlow.

.2.3 Forces on an element shall be measured atncrements of rotation of approximately 1° between theimit of ± 10° to the horizontal. BS EN 40-3-1 requireshe maximum value between ± 5° to the horizontal but a

ore conservative value shall be adopted where largencreases of coefficients are obtained between 5° and0° to the horizontal. During testing the effects of smalllan rotations about the point of fixing shall also beaken into account. Where an increase in shapeoefficient obtained with a rotation within the limits of 10° then this value shall be adopted.

D/1

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