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design of noise barriers adjacent to railways - Queensland Rail

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DESIGN OF NOISE BARRIERS ADJACENT TO RAILWAYS, Revision A7.3.5 Panel DesignWhere the method <strong>of</strong> construction requires thatthe <strong>to</strong>p <strong>of</strong> the barrier be stepped, the Contrac<strong>to</strong>ris <strong>to</strong> build the <strong>noise</strong> barrier so that the <strong>to</strong>p <strong>of</strong> thewall is not less than the calculated minimumheight, and steps are <strong>to</strong> be equally incrementedin height, as far as possible.Top panels are <strong>to</strong> have a rounded edge <strong>to</strong> deterpeople walking on it, and also <strong>to</strong> improve theappearance <strong>of</strong> the barrier. Any edge cappingmust be suitably protected against corrosion andhave the same life span as the panel.The bot<strong>to</strong>ms <strong>of</strong> <strong>noise</strong> barrier panels are <strong>to</strong> followeither ground level or an edge strip.Where the method <strong>of</strong> construction requires thatthe bot<strong>to</strong>m <strong>of</strong> the barrier be stepped, no gapsare <strong>to</strong> be left as a result <strong>of</strong> stepping, unlessrequired for drainage purposes. The Contrac<strong>to</strong>ris <strong>to</strong> fill all gaps with concrete or other materialapproved by <strong>Queensland</strong> <strong>Rail</strong>.The barrier must be continuous and solid withno visible or light gaps between panels. Formaximum effectiveness, the barrier is <strong>to</strong> becontinuous down <strong>to</strong> ground level, with any gapsfilled (e.g. as a result <strong>of</strong> stepping).If damming <strong>of</strong> water at the bot<strong>to</strong>m <strong>of</strong> the barrieris likely, discrete drainage points are <strong>to</strong> beincorporated in<strong>to</strong> the <strong>design</strong>s withoutcompromising the barrier’s ability <strong>to</strong> achieveacceptable <strong>noise</strong> levels. The drainage pointsmust not concentrate water flow.Panels must have positive fastening devices <strong>to</strong>deter theft. Connection details are <strong>to</strong> permiterection and removal <strong>of</strong> the panels on a regularbasis.Noise <strong>barriers</strong> located close <strong>to</strong> tracks, such thatvehicles cannot gain access between track andbarrier, must consist <strong>of</strong> panels that can be easilyremoved and manhandled.7.3.6 Panel Serviceability DesignThe horizontal deflection <strong>of</strong> the panel underserviceability wind is <strong>to</strong> be limited <strong>to</strong> Span/150.To eliminate the need for electrical earthing, steelcomponents from panel <strong>to</strong> panel must beinsulated from each other.Page 6 <strong>of</strong> 97.4 FastenersConnections must be <strong>design</strong>ed <strong>to</strong> adequatelysecure all members for the <strong>design</strong> loading andallow for panel movement where necessary.Use <strong>of</strong> screws will not be permitted.For connections involving timber components,the bolts, etc. must be retightened when thestructure reaches the site equilibrium moisturecontent.All bolts, nuts and washers must comply with AS1111, 1112 and 1237, as appropriate.All bolts, nuts and washers must be hot dipgalvanised with a minimum 50 microns thicknesscoating in accordance with AS 1214. All washersmust be hot dip galvanised in accordance withAS 4680.Alternative coatings will be considered, providedthey have at least the equivalent durability as thatspecified.Zinc plated bolts or nails are not acceptable.7.5 Footings7.5.1 Footing TypeFootings are preferably <strong>to</strong> be “bored”, but “block“footings are allowed if circumstances renderboring impractical.7.5.2 Block FootingThe block footing may be used where one <strong>of</strong> thefollowing constraints exists:• access for drilling rig is not practical,• the ground is not suitable for boring or• the foundation depth is limited because <strong>of</strong> anunderground service or culvert.The footing must be <strong>design</strong>ed <strong>to</strong> preventinstability in overturning, uplift and sliding inaccordance with AS/NZS 1170.0 for ultimateloads.To resist temperature and shrinkage cracking,reinforcement <strong>of</strong> not less than 500 mm 2 /m ineach direction must be used in exposedsurfaces.The <strong>to</strong>p <strong>of</strong> the footing is <strong>to</strong> be at least 300 mmbelow ground level.


DESIGN OF NOISE BARRIERS ADJACENT TO RAILWAYS, Revision A7.5.3 Bored FootingThe bored footing is <strong>to</strong> be used where access isavailable and the ground is suitable for boring.The <strong>design</strong>er is <strong>to</strong> use the Broms method (refer<strong>to</strong> Appendix B) <strong>to</strong> calculate footing depth.Footing depth is <strong>to</strong> be increased by anappropriate fac<strong>to</strong>r (at least 1.5) if the footing isless than 1.5 m from the edge <strong>of</strong> anembankment or cutting.It is <strong>to</strong> be assumed that existing cuttings within<strong>Queensland</strong> <strong>Rail</strong> property will be widened <strong>to</strong>within 1.0 m <strong>of</strong> the property boundary. Theminimum depth <strong>of</strong> footing is <strong>to</strong> be twice thefooting diameter.7.5.4 FinishThe <strong>to</strong>p <strong>of</strong> the footing must be shaped <strong>to</strong> shedwater away from the post.7.6 Protective Painting <strong>of</strong> Steel Posts andFootingsAfter post installation, a neat, continuous, waterbased,bituminous paint "collar" is <strong>to</strong> be appliedon every post up <strong>to</strong> 150 mm above the finishedconcrete footing level. This collar is <strong>to</strong> extendon<strong>to</strong> the <strong>adjacent</strong> concrete surface <strong>of</strong> the footingfor a minimum 100 mm from any point on thepost.CRITERIAPosts: Variation fromverticalProtective treatment <strong>of</strong>timberHot dip galvanizing:structural membersTOLERANCE5 mm/m forisolated postsParallel foradjoining postsIn accordance withthis document andTUMACoating thickness<strong>of</strong> 80 microns min.in accordance withAS46809.0 ASSOCIATED COSTS INCURREDBY QUEENSLAND RAILAll <strong>of</strong> <strong>Queensland</strong> <strong>Rail</strong>’s costs associated withthe review, <strong>design</strong> and construction <strong>of</strong> the <strong>noise</strong><strong>barriers</strong> and the implementation <strong>of</strong> <strong>Queensland</strong><strong>Rail</strong>’s Technical Requirements will be charged<strong>to</strong> the building owner or its agent. This includesany remedial work necessary <strong>to</strong> <strong>Queensland</strong><strong>Rail</strong> property as the result <strong>of</strong> this work and anyaccidental damage, as well as costs associatedwith train delays. Rates will be set by<strong>Queensland</strong> <strong>Rail</strong>.CONSTRUCTION TOLERANCESTolerances are only permitted in order <strong>to</strong> caterfor variations caused during manufacture andconstruction.The following <strong>to</strong>lerances are <strong>to</strong> apply <strong>to</strong> theconstruction <strong>of</strong> the <strong>noise</strong> <strong>barriers</strong>.TABLE 1 – TOLERANCESCRITERIADepth <strong>of</strong> footingCentre <strong>to</strong> centredistance between postsThickness <strong>of</strong> <strong>noise</strong>barrier panelsTOLERANCE+ 200 mm- 50 mm+ 10 mm- 10 mm+ 5 mm- 1 mmPage 7 <strong>of</strong> 9


DESIGN OF NOISE BARRIERS ADJACENT TO RAILWAYS, Revision AAPPENDIX A: IMPACT TEST FOR NOISE BARRIER PANELSNoise Barrier Panels must be able <strong>to</strong> withstand the following Impact Test.The test panel is <strong>to</strong> be subjected <strong>to</strong> impact energy <strong>of</strong> 150 Joule, consisting <strong>of</strong> four (4) loadrepetitions <strong>of</strong> an impac<strong>to</strong>r. This is <strong>to</strong> simulate a concerted attack by vandals.The impac<strong>to</strong>r is <strong>to</strong> be manufactured from steel <strong>of</strong> density 7.8 t/m 3 and spherical in shape.An impact energy <strong>of</strong> 150 Joule is achieved by dropping the impac<strong>to</strong>r from a specific height, H (inmm) on<strong>to</strong> the horizontal test panel. The impac<strong>to</strong>r is raised so that its centre <strong>of</strong> gravity is atheight, H which is calculated from the equation:H =15300mwhere H = Drop Height in millimetresm = Mass <strong>of</strong> Impac<strong>to</strong>r in kilogramsFor solid panels, the point <strong>of</strong> impact is typically at mid-span and 150 mm from the free edge orin a location <strong>to</strong> give the worst effect. If the panel consists <strong>of</strong> boards that have internal voids, thepoint <strong>of</strong> impact must be mid-span and centrally between the internal stiffeners <strong>of</strong> the outermostboard. Where applicable, the panel must not weigh more than the maximum allowable weightdefined in the Technical Requirement.The panel is considered <strong>to</strong> have passed the test if it remains serviceable after the four loadrepetitions. That is, it will still perform its function as a <strong>noise</strong> barrier and can withstand its<strong>design</strong> load without shortening its service life.The results <strong>of</strong> the test are <strong>to</strong> be certified by a Registered Pr<strong>of</strong>essional Engineer <strong>of</strong> <strong>Queensland</strong>(RPEQ).Page 8 <strong>of</strong> 9


DESIGN OF NOISE BARRIERS ADJACENT TO RAILWAYS, Revision AAPPENDIX B: BROMS METHOD FOR BORED FOUNDATIONSAn acceptable method for the <strong>design</strong> <strong>of</strong> footing depth is based on Brom’s theory as follows.Applicable case is short pile in cohesive soils.HuF = 9 × Su× D............................................................................................................................................Mmax= Hu× ( E + 1.5D+ 0. 5F)............................................................................................................................................G =⎛ M⎜⎝ 2.25×Smaxu⎞⎟× D ⎠L = 1. 5D+ F + G............................................................................................................................................Where:DEF= ..................................................................................................... Diameter <strong>of</strong> footing (m)= ....................................................................................................Height <strong>of</strong> barrier / 2 (m)......................................................................... Depth <strong>to</strong> zero shear point minus 1.5*D (m)G = Depth <strong>of</strong> footing minus F minus 1.5*D (m)H u = ............................................................................................... Ultimate lateral shear (kN)L= ......................................................................................................... Depth <strong>of</strong> footing (m)M max = .......................................... Maximum ultimate lateral bending moment in footing (kN.m)S u= .............................................................. Fac<strong>to</strong>red undrained shear strength <strong>of</strong> soil (kPa)adfPage 9 <strong>of</strong> 9

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