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After the existing bridge is removed from its current position, which is currently programmed totake place between October 2013 and February 2014, commencement of the replacement bridgeworks would begin, with the temporary river piers maintained in place to facilitate construction ofthe replacement bridge by launching or some other means which permits off-site construction.All works relating to the removal of the bridge in the river corridor would require safe environmentalprotection including protective shrouds as necessary.Existing Destructor BridgeLayoutNumerous constraints have informed the structural typology and the positioning of the new bridge,these are:- The absence of historical survey data for the extensive services in the ground onboth banks means that there would be a significant risk associated with movingthe abutments outside of their existing location. It is therefore proposedthat new piles are drilled through the existing abutment foundations. Thisapproach also avoids the potential risks associated with working under the water table.- The minimal vertical offset between the top of the required river clearanceenvelope and tie-in levels for the highway requires that the majority of structural depth mustbe made above deck level, but as a consequence the bridge widens.- The limited plan space available between building B16 and the National Gridenclosure means that only a small set of structural forms can fit on the site.- It is not possible to have supports in the river for reasons of flow, and to maintainsafe passage and views for river and towpath users.Following an extensive options appraisal, it was concluded that only two typologies could bepractically implemented on site – a solution above deck that comprises a 2.1m in situ concreteedge beam or an asymmetrical steel arch truss solution.Page 3

AmountCross Section at Midspan of Structure (Ref. from KA052/TPA/102)The proposed replacement bridge is for two lanes of highway with 2.5m of pedestrian walkway onthe east side and a 4m shared pedestrian cycleway on the west side. Traffic barriers will separatecyclists from vehicles.4m 0.8m 0.8m 0.6m5.5m0.6m2.5mCycle/Pedestrian WayCarriagewayPedestrian WayCross Section of ArchScaleRev.DateNot for ConstructionKnight Architects LimitedProject:Scale:Drawing Title:Do Not Scale Except for Planning PurposesOld MetalworksCrest Nicholson1:150 at A3Destructor10 Queens RoadDestructor Bridge ReplacementSection DHigh WycombeThe inherent structural efficiency and economy of material in the arch truss produces a BridgeBucks HP13 6AQsolutionTelephone 01494 525 500Work Stage / Status:Date:DrawingRevision:Number:© Copyright Knight Architects Limited 2013Email info@knightarchitects.co.uk www.knightarchitects.co.uk PlanningMarch 2013KA052/TPA/302Othat is highly transparent, both from towpath level and also for pedestrians looking off the bridge.A gateway is formed by buildings B16 and B18 accentuated by the visual promenade of trees,implying a division of space between pedestrian and vehicles. This visually permeable barriercan be seen to extend over the bridge through the hangers of the arch. The plane of structure ispositioned to complement existing lines of sight and movement within the master plan design,connecting Bath Western Riverside to Victoria Park.CommentsAlignmentPage 4

DesignThe fabricated steel arch follows a minimalist aesthetic with structural features like the slender steelplate hangers, whose proportions echo the deep window openings of the new BWR vernacular, acontemporary interpretation of the Bath Georgian style. It is a crafted object which reflects the skillof the engineering process that is so important in the history of Bath, and of this site in particular.The gentle arching curve of the top chord is perfectly complementary to the similarly proportionedsag curve of the Victoria Bridge suspension chains.ColourProposed Destructor BridgeExtensive research into the colour for the bridge has favoured a RAL 7035 ‘Light Grey’ colourfor the arch with a dark grey parapet and soffit. From the towpath, the light grey arch against theskyline is transparent and does not impose on views of the river corridor. On deck, it complimentsthe Bath stone of the BWR scheme and is not intrusive to the bridge user, in way that both a darkgreen and a dark grey were found to be. The RAL 7035 ‘Light Grey’ colour selected for the archis more tolerable to atmospheric spoiling and is less strident than a pure bright white, which ismore suited to landmark structures. The dark grey parapet and soffit is understated and does notdetract attention from the surrounding context. It is proposed that the steel arch will be coated witha highways approved RAL 7035 ‘Light Grey’, with all other steel structure to be painted RAL 7024Graphite Grey, both high specification bridge paint systems.RAL 6016 ‘Turquoise Green’ Arch - Awkwardcontrast against Bath stone and Victoria Bridge.RAL 7011 ‘Iron Grey’ Arch - Visually heavy andoppressive. Uncomfortable on deck experienceRAL7035 ‘Light Grey’ Arch PROPOSED OPTIONPage 5

FinishesThe parapet will be made up of parallel vertical flat bars with nominal 100mm gaps. This doesnot have a discernible module so it is not read against the arch, meaning the visual focus is firmlyon the arch rather than the edge of the bridge. The user is aware of the degree of transparencyalongside them and this informs their forward view. For the cycle rail a grade 316 satin finishedstainless steel will be used.Opportunities for bench seating have been created between the arch hangers. A sustainablysourced certified hardwood seating, such as European oak will provide the bench top, withintegrated architectural lighting. All services shall be hidden so they are not visible on any exteriorsurfaces. The pedestrian walkways will comprise a thin layer of concrete overlaid with a thin,durable wearing coarse of epoxy fixed crushed aggregate, the colour of which has been selectedto match the Grey Pennant Tegula set proposed for the paving either side of the bridge.On the sloping faces of the bridge soffit, there will be a punched mesh grille so as to protect theservices and provide a visual screen. The ribbed soffit between the sloping faces will be left uncladas there will be no services, demonstrating the clean structural form of the bridge. The piers andabutments will be clad in blue engineering brick which references those used on the existingDestructor Bridge, and also suits the Bath stone and dark zinc used elsewhere in the project.ConstructionIMAGE SHOWING PERMANENT STAIR CONFIGURATION. TO BE IMPLEMENTED AS DEPOT SITE IS DEVELOPEDThe steel arch solution does not require any permanent works within the river. The deck can beeasily assembled on the south side of the river and launched across using temporary supports thatwill be required for the safe renewal of the existing structure, with or without the edge cantileversalready fitted, resulting in a rapid construction process. The assembling of pre-fabricated units andlaunching involves the least time on site and consequently minimises disruption of other activities.It also reduces the risks associated with fabrication and construction, in controlled off-site workingconditions.LightingThe impact on the river corridor is reduced by moving bright highway lighting away from the bridge.Instead there will be low level handrail lighting to provide a wash of light over the deck which willilluminate the pedestrian and cycle ways and the faces of oncoming users. Diffused uplighters willgently light the arch, making the slender structure legible from the towpath at night.Page 6