An Bord Pleanála Inspector’s Report Marlborough Street Public Transport Priority Bridge. 1 Introduction 1.1 An Environmental Impact Statement was prepared by Dublin City Council in respect of the above bridge development pursuant to Section 50 of the Roads Act 1993 and Article 8 (b) of the Roads Regulations, 1994. 1.2 Dublin City Council wrote to the Board, in September 2008, in accordance with Section 51 (1) (c) of the Roads Act 1993, Bord Reference 29NHD00011, seeking a direction in relation to the preparation of an environmental impact statement in respect of ‘Marlborough Public Transport Priority Bridge. The Board gave a direction that an Environmental Impact Statement should be prepared. 1.3 In accordance with Sections 215 and 267 of the Planning and Development Act, 2000, matters in relation to this development, which were to be determined by the Minister, are now to be determined by An Bord Pleanála. 1.4 Under Article 6 of the European Communities (Environmental Impact Assessment) (Amendment) Regulations, 2000, the Board decided to hold an Oral Hearing in this case. 1.5 The Oral Hearing was held at the Board’s Offices, Marlborough St., Dublin on the 22nd June 2009. Ms. Dolores McCague Senior Inspector conducted the Hearing. Mr. Danny O’Connor, another Senior Inspector with the Board, is advising on matters relating to hydrological and traffic aspects of the proposal, and he attended the Hearing and participated in relevant discussions, at the invitation of the presiding inspector. 1.6 The proceedings were recorded by a stenographer and appear in a typed volume accompanying this report. PL29NHA0022 An Bord Pleanála Page 1 of 21 1.7 A summary of the hearing is referred to at the relevant sections of this report. One document was submitted at the hearing, a print out of the ‘Powerpoint’ presentation which was presented at the hearing; and it is attached as appendix 1 to this report. 1.8 Mr Danny O Connor has prepared a written report on traffic and hydrological related issues and this is attached in the separate volume of appendices to this report. This is referred to in this report as ‘Mr O’Connor’s report’ 1.9 I inspected the site on the 18th June 2009. Photographs taken at the time of inspection are attached at the end of this report. 1.10 It is my view that all statutory requirements appear to have been complied with. 2 PROPOSED DEVELOPMENT 2.1 This proposal relates to a proposed bridge across the River Liffey in Dublin City centre, to be located between O’Connell Bridge and Butt Bridge, linking Marlborough Street and Eden Quay to Hawkins Street and Burgh Quay. 2.2 The link that the bridge will provide, between Hawkins Street and Marlborough Street, will be beneficial locally and to the wider city, providing for buses and Luas as well as pedestrians and cyclists. 2.3 The bridge will accommodate two bus lanes, one southbound light rail (Luas ) track, two footpaths and two cycle tracks. 2.4 Initially the bridge will be utilized to carry diverted traffic which will use the bridge in a northbound direction during the proposed Metro construction works in the vicinity of O’Connell Bridge. 2.5 Purpose of the project: Objectives include to: Provide an architecturally sensitive priority bridge linking Marlborough Street and Eden Quay to Hawkins Street and Burgh Quay, Meet the traffic, layout structural and environmental requirements of the public transport priority bridge, Meet the architectural requirements and complement the existing O’Connell Bridge, Butt Bridge and quay walls which are all listed structures, Provide two southbound bus lanes, one southbound light rail (Luas) track, two footpaths and two cycletracks (one northbound and one southbound). PL29NHA0022 An Bord Pleanála Page 2 of 21 2.6 Description of the quays: 2.6.1 The River Liffey is approximately 46m wide at the location of the proposed bridge. The river has an approximate tidal range of +1.75 mOD to -1.75mOD Malin Head at this location. 2.6.2 The quays, which are not parallel in plan, carry highly trafficked roads and footpaths Many of the buildings along the quays are of historic interest with some being listed. The quay walls on either side of the river are of masonry construction and date from circa 1663 to the early 19th century. A boardwalk of approximately 3.5m width is cantilevered from the north quay wall. Both quays are tree lined on the river side of their respective roads. 2.6.3 Eden Quay carries two eastbound traffic lanes and a contraflow westbound bus lane in the vicinity of the proposed bridge location. An eastbound cycle lane is also provided north of the eastbound traffic lanes. Pedestrian crossing facilities are provided crossing Eden Quay to the west of the Eden Quay / Marlborough Street Junction. 2.6.4 The Eden Quay / Marlborough Street Junction is a left in / left out junction for both buses and regular vehicular traffic although it also accommodates a right turn for buses trying to use the existing westbound bus lane. An eastbound cycle lane is also provided north of the eastbound traffic lane. 2.6.5 Burgh Quay carries two westbound traffic lanes and a westbound bus lane in the vicinity of the proposed bridge location. These two traffic lanes branch out to become three lanes just west of the proposed bridge site. On Burgh Quay a westbound cycle lane is also provided south of the westbound bus lane. Pedestrian crossing facilities are provided for crossing Hawkins Street at the Burgh Quay / Hawkins Street Junction. 2.6.6 Burgh Quay / Hawkins Street junction allows entry only to Hawkins Street from Burgh Quay. Bus entry is split from general traffic entry by a traffic island however these two traffic lanes merge south of the junction. 2.6.7 There are currently no cycle facilities on either O’Connell Bridge or Butt Bridge. 2.6.8 Pedestrian crossing facilities are currently provided at O’Connell Bridge and Butt Bridge, however long waiting times and heavy volumes of traffic are associated with these crossing points. The pedestrian crossing facility at Butt Bridge does not provide for pedestrian movement on all arms. 2.7 Description of the proposed development 2.7.1 The description of the development in the EIS states that: The design is a single span concrete structure, 65m long and 26m wide, which forms abutments at the quay walls. It is a shallow mid span concrete structure, forming a shallow parabolic curve which tightens before reaching the quay walls, where there are abutments. The parabolic curve, which the underside of the PL29NHA0022 An Bord Pleanála Page 3 of 21 bridge follows, is achieved by making the in-situ abutments integral with the post- tensioned concrete deck. The bridge will act as a portal frame, carrying horizontal and vertical loads into the overburden and rock below and therefore, will be designed so as not to exert longitudinal loading on the existing quay walls. The proposed bridge will tie into the existing quays located to the north and south. Due to the limitations on the geometry of the Luas rails and the navigational requirements in the river, the vertical alignment of the bridge deck requires a build up of levels on the existing quays. The levels in the vicinity of the new bridge will be raised by approximately ½ m. These will be designed to tie in with the existing roads and footpaths. It is not envisaged that the frontage of the existing buildings on the quays will be affected by the raised level of the bridge approaches. 2.7.2 At the intersection with the river bed the abutments form a double–bulge on plan. This allows the structure to pass either side of the existing inverted siphon drain located in the riverbed, creates a sinuous spread-water through its geographical resolution and also limits the protrusion of the abutment into the river. As the abutment rises, the double curvature gradually flattens out and becomes a gentle single curve underbelly of the bridge. The choice of abutments considered the need to achieve a laminar flow close to the bridge to minimise turbulence, because of proximity to other bridges in the area. 2.7.3 The abutments are to be of reinforced concrete construction and are to be integral with the superstructure. The back face of the abutment will be set at a sufficient clearance from the quay walls to ensure that longitudinal loads are not transferred into the walls. The void between the abutments and the quay walls is to be filled with a compressible material. 2.7.4 The location of the abutments on the riverside of the quay walls has the added benefit of minimising any disruption to traffic and pedestrians during the construction phase. 2.7.5 Lighting and pylons to support the Luas are not located on the bridge. Two poles positioned at each of the two thresholds provide lighting and further public lighting is integrated into various bridge elements. Existing quay walls above existing road level have to be removed; and footpath levels raised at the four corners, requiring additional courses of stone in the quay walls at these locations to provide walls of sufficient height relative to the footpaths. 2.7.6 Footpath widths on the bridge have been considered in some detail. The analysis recommended a minimum width of 2.67m. The 3m width provides for increased usage with time due to increases in population, proximity of Luas stops, and the potential for commercial development of Marlborough Street and Hawkins Street.