DMRB VOLUME 1 SECTION 3 PART 7- BD 57/01 - DESIGN …

1 August 2001 DESIGN MANUAL FOR ROADS AND BRIDGESVOLUME 1 HIGHWAY STRUCTURES:APPROVAL PROCEDURESAND GENERAL DESIGNSECTION 3 GENERAL DESIGNPA RT 7BD 57/01 DESIGN FOR DURABILITYSUMMARYThe existing Standard and Advice Note (BD 57 andBA 57) have been updated to include:a)Lifting of the moratorium on internal groutedpost-tensioned construction (excluding internalgrouted post-tensioned segmental structures).b)Improvements to durability that can be made bythe use of controlled permeability formwork,dense near surface concrete, corrosion inhibitorsand other materials such as lightweight aggregateconcrete, and stainless steel )To include references to thaumasite )To rationalise references and FOR USEThis revised Standard is to be incorporated in document supersedes BD 57/95, which isnow BD 57/95, which is superseded byBD 57/01 , and archive as BD 57/01 in VOLUME 1, SECTION 3, part this sheet as : A quarterly index with a full set of VolumeContents Pages is available separately from TheStationery Office Ltd.

2 BD 57/01 DESIGN for DurabilitySummary:The existing Standard and Advice Note (BD 57 and BA 57) have been updatedto include:a) Lifting of the moratorium on internal grouted post-tensioned construction.(excluding internal grouted post-tensioned segmental structures).b) Improvements to durability that can be made by the use of controlledpermeability formwork, dense near surface concrete, corrosion inhibitorsand other materials such as lightweight aggregate concrete, and stainlesssteel ) To include references to thaumasite sulfate ) To rationalise references and MANUAL FOR ROADS AND BRIDGESTHE HIGHWAYS AGENCYSCOTTISH EXECUTIVE DEVELOPMENT DEPARTMENTTHE NATIONAL ASSEMBLY FOR WALESCYNULLIAD CENEDLAETHOL CYMRUTHE DEPARTMENT FOR REGIONAL DEVELOPMENTNORTHERN IRELANDV olume 1 SECTION 3 part 7 BD 57/01 August 2001 REGISTRATION OF AMENDMENTSA mendPage NoSignature & Date ofAmendPage NoSignature & Date ofNoincorporation ofNoincorporation ofamendmentsamendmentsRegistration of AmendmentsVolume 1 SECTION 3 part 7 BD 57/01 August 2001 REGISTRATION OF AMENDMENTSA mendPage NoSignature & Date ofAmendPage NoSignature & Date ofNoincorporation ofNoincorporation ofamendmentsamendmentsRegistration of AmendmentsVOLUME 1 HIGHWAY STRUCTURES.

3 APPROVAL PROCEDURESAND GENERAL DESIGNSECTION 3 GENERAL DESIGNPA RT 7BD 57/01 DESIGN FOR Durability - The Conceptual MANUAL FOR ROADS AND BRIDGESA ugust 2001 VOLUME 1 SECTION 3 part 7 BD 57/01 August 20011/1 Chapter 1 Introduction1. has been found that the durability of manybridges in the Overseeing Organisations stock has beenlimited by decisions made at the DESIGN stage in relationto the bridge configuration and the choice of decisions were often limited to a designphilosophy in which minimising the initial capital costwas paramount. The Overseeing Organisations are keento promote the concept of DESIGN for durability, therebyshifting the emphasis to a lowest whole-life cost Standard is to be read in conjunction withBA 57 ( dmrb ), which gives further advice andbackground information on the topics covered practicable, the recommendations of BA 57shall be applied to all bridge existing Standard and Advice Note (BD 57and BA 57) published in 1995 have been updated toinclude:a)Lifting of the moratorium on internal groutedpost-tensioned construction (except for segmentalconstruction).

4 B)Improvements to durability that can be made bythe use of controlled permeability formwork,dense near surface concrete, corrosion inhibitorsand other materials such as lightweight aggregateconcrete and stainless steel )To include references to thaumasite )To rationalise references and this Standard is applied for the DESIGN ofprecast concrete elements which are procured through acontract incorporating the Specification for HighwayWorks (MCHW 1), products conforming to equivalentstandards and specifications of other member States ofthe European Economic Area will be acceptable inaccordance with the terms of the 104 and 105 Series ofClauses of that Specification. Any contract for theprocurement of precast concrete elements which doesnot include these Clauses must contain a suitable clauseof mutual recognition having the same effect regardingwhich advice should be purpose of this Standard is to giverequirements which, when used in conjunction with theexisting framework of the Overseeing Organisations DESIGN Standards for highway structures, will improvethe durability and minimise the whole-life costs of newhighway requirements of this Standard apply to thedesign of all the Overseeing Organisations bridgesincluding retaining walls and abutments.

5 Whilst thisStandard has not been written specifically to beapplicable to footbridges, pipe bridges and sign andsignal gantries, most of the principles may be applied tosuch Standard is to be implemented forthwith forall schemes currently being prepared provided that, inthe opinion of the Overseeing Organisation, this wouldnot result in significant additional expense or delayprogress. DESIGN Organisations should confirm itsapplication to particular schemes with the reference is made in this Standard to adequate or suitable provisions, the OverseeingOrganisations shall determine whether the requirementsof this Standard have been met. In this regard thedecision of the Overseeing Organisations is 1 SECTION 3 part 7 BD 57/01 August 20012/1 Chapter 2 Improved Durability - The Conceptual Stage2.

6 IMPROVED DURABILITY - THE CONCEPTUALSTAGES tructural structures have proved to be moredurable than structures with simply supported decks,primarily because deck joints have allowed salty waterto leak through to piers and abutments. In principle allbridges shall therefore be designed as continuous overintermediate supports unless special circumstancesexist. Such continuity may be either full continuity ofthe whole deck structure or partial continuity of usuallythe deck slab are serious inspection construction andmaintenance problems associated with in-spandiscontinuities, generally referred to as shall therefore not be provided in bridge decksunless the agreement of the Overseeing Organisation principle bridges with lengths not exceeding60m and skews not exceeding 30 shall in addition bedesigned as integral bridges, with abutments connecteddirectly to the bridge deck without movement joints forexpansion or contraction of the deck.

7 Where thedesigner considers that either this form of construction,known as integral construction, or a continuousstructure is not appropriate, for instance where largedifferential settlements are anticipated or where anexceptionally high end restraint could result inunacceptable stress or deformation in the deck,articulated construction may be used with theagreement of the Overseeing clearance considerations permit,structures of the buried type shall be considered for allbridges. It should be noted that for longer bridges, thecost penalties of the use of buried structures mayexceed their benefits. In doubtful cases, the OverseeingOrganisation shall adjudicate whether normal or buriedconstruction is designing concrete structures,consideration shall be given to all possible means ofreducing or eliminating the use of corrodablereinforcement.

8 This includes the use of plain (mass)concrete for abutments, wing walls and retaining use of arch structures where ground conditionspermit may also be considered. Options open todesigners include the use of precast unreinforcedvoussoirs (with or without natural stone facing),unreinforced concrete arches incorporating shrinkagereducing additives and similar structures withproprietary or other crack inducers at quarter the benefits of using plain concrete are marginalthe Overseeing Organisation shall adjudicate whetherplain or reinforced concrete shall be requirements of BS 5400: part 4, , and of BD 28 ( dmrb ), need not apply toplain concrete structures, provided that they are suitablyclad or treated to conceal thermally-induced fixings of any cladding elements shall be madeusing non-corrosive provision for access shall be made forthe following purposes.

9 A)cleaning and paintingb)maintenancec)jacking, removal/replacement of bearingsd)inspection of closed cell and box providing such access, all the requirements of theHealth and Safety legislation and other relevantrequirements shall be fully observed; provision foraccess in excess of the minimum requirements shall beadopted wherever possible. Access shall be providedfrom below deck level, to avoid access through use of any of the access facilitiesprovided for bridge inspection and maintenance shall beprevented by the provision of suitable barriers, coversetc. Colonisation of accessible areas by plants, animalsand birds shall be discouraged by suitable does not affect the possible specific provision ofbird or bat boxes etc for nature conservation and relatedpurposes, but such provision shall be consistent withthe need to keep all access areas clean and free 1 SECTION 3 part 7 BD 57/01 August 20012/2 Chapter 2 Improved Durability - The Conceptual galleries shall be provided below allbridge deck expansion and rotational joints.

10 The widthand headroom clearance of galleries shall preferably beat least 1000 x 1800 mm respectively, and shall neverbe less than 800 x 1500 mm. All abutment galleriesshall be provided with adequate permanent ventilationto the outside atmosphere, and an adequate level ofnatural illumination, usually via the Duct the time being segmental post-tensionedconcrete bridges with an internal grouted system shallnot be used. Segmental bridges incorporating externalpost-tensioned systems, and non-segmental with eitherexternal or internal systems may be Manufactured a proprietary manufactured structure is tobe provided by the Contractor, the maintenance policyfor the structure shall be included in the Approval inPrinciple form, (AIP).