DS/CSB/522

THE KNOWLEDGE Issue No 03 Issue Date July 09

Concrete Step Barrier Design Guidance CSB: Foundation and Restraint CSB: Foundation and Restraint:

DRAWINGS CSB/1001

APPLICATIONS

A surface mounted CSB is the preferred Britpave product The key features of Surface-Mounted Step Barrier are: and should be the default method of installation used in most situations. • Same barrier height, step height, width and face profile as standard CSB products (Data Sheet However on decks the embedded barrier must be DS/CSB/502). • H2 containment, working width W2 (for standard width used see (Data Sheet DS/CSB/504 and Britpave Report barrier). BP/35 for details). • Barrier is mounted directly onto bituminous surface course –no separate foundation or restraint required. Figure 1 200

Reinforcement Surface-Mounted Step Barrier, in both the standard and variable profile, was successfully crash tested at MIRA in April 2006 and conforms to BS EN 13171. 900 Designers and installers should note that the stability and performance of the barrier is directly attributable to Finished road level the foundation materials on which the barrier sits, and 542 good adhesion and interlock between the barrier concrete and bituminous surface course must be achieved. The Britpave Surface-Mounted Step Barrier foundation (Figure 3) must be no less than 100 mm bituminous pavement material in accordance with SHW Figure 2 Series 9002 on 150 mm compacted Type 1 material in accordance with SHW Series 8003. At least 100 mm of compacted bituminous pavement material must extend beyond the barrier on the non-traffic face. These minimum foundation conditions are those under which the Surface Mounted Barrier was tested. Installation under conditions other than those described in the Britpave data sheets and drawings will result in a barrier which does not conform to BS EN 1317. • Step Barrier must not be installed directly on granular Developmental modelling and crash test simulation using material. LS-DYNA Figure 3 The main difference of surface mounted compared to Traffic face embedded CSB is that it is constructed directly on the bituminous or concrete , and does not require a 100 min separate concrete foundation or restraint. Soft central reserve 100 min

This reduces construction time and traffic management, Finished requiring less excavation, and less material compared to road level embedded CSB. Bituminous pavement 100 min 1 Compacted Type 1 2 150 min Britpave Surface-Mounted Step Barrier (Figure 1) is an Minimum foundation requirements for Britpave Step Barrier innovative product developed by Britpave to simplify installation of CSB. The barrier was developed using a combination of computer modelling and simulation

(Figure 2) and empirical testing.

CONCRETE STEP BARRIER Design Guidance DSC/CSB/522 CSB: Foundation and Restraint Prepared for Britpave by Arup E-mail [email protected] Facsimile 01276 33160 Website www.britpave.org.uk CSB: Foundation and Restraint DS/CSB/522 Britpave Riverside House, 4 Meadows Business Park, Station Approach, Blackwater, Camberley, Surrey GU17 9AB Prepared for Britpaveby Arup CONCRETE STEPBARRIERDesign Guidance described inBSEN13036-1 be measured usingavolumetricsandpatchtechniqueas surface course,onwhichthebarrieristobecast,should length. Surfacemacrotexture ofthebituminous/concrete or thecompletesectionwhere thisislessthan1000min on each1000mlengthwhere barrieristobeinstalled, bituminous surfacecourseshouldnotbelessthan0.7mm, The averagedepthofpavementsurfacemacrotexture ofthe characteristics suchasbleedingorfattingup. The surfaceofthepavementshouldalsonotexhibit concrete andthebituminous/concrete surfacecourse. affect theformationofbondbetweenslipformed contaminant, fluidorothermaterialthatmayadversely cast mustbefree from loosematerial,detritusandany concrete barrier. Thesurfaceonwhichthebarrieristobe material shouldbecleanedpriortoslipformingthe The surfaceofthebituminousorconcrete pavement concrete intopores inthebituminousmaterial. EN 1317.Theadhesivebondisformedbyinterlockofthe a Surface-MountedStepBarrier, andcompliancewithBS bituminous surfacecourseiscriticalinensuringstabilityof Adhesion betweentheslipformedStepBarrierand combination ofsurfacecourseandbindercourse. material of100mmisrequired. Thismaycompriseofa A minimumthicknessofbituminousorconcrete pavement Surface Course arrangements. Figures 4to6showtypicalsurfacemountedCSB the basematerial. consideration totheneedforconstructiontrafficrunon additional strength isrequired. Thedesignershouldgive be considered, where ground conditionsdictatethat specified anduseofhydraulicallyboundmaterialsmay Type 1granularmaterial.Agreater thicknessmaybe The baseshallbeatleasta150mmlayerofcompacted Base 4 . Typical layoutfullyhardened centralreserve Typical layout,nodrainage Typical layout,softcentralreserve Finished ro 4 3 2 1 Finished ro BSEN13036-1Measurement ofpavementsurfacemacro texture

Specification for Works, Volume 1, Series 800. Road Specification for Highway Works, Volume 1, Series 900. Road BS EN1317-2:Road Restraint Systems. Performance classes, depth usingavolumetricpatch technique Pavements –BituminousBoundMaterials barriers impact testacceptancecriteriaandmethodsforsafety Mixtures Pavements - Unbound, Cement and other Hydraulically Bound Figure 6 Figure 4 Figure 5 T raffic face ad level Hard (No drainagefeatur ad level be locatedinthiszon ened centralr Set back DSC/CSB/522 T raffic face T raffic face eserve es to e Appr CSB:Foundation andRestraint Drainage system Hard oved lineardrainagesystem ened centralr Issue DateJuly09 THE KNOWLEDGE Finished ro foundation R estraint eserve Issue No03 Soft central ad level r eserve 150 100