Waterford Bypass

ENGINEERS IRELAND WATERFORD BYPASS WATERFORD BYPASS JOHN T. MURPHY, BE, CEng, FIEI, HDipMM, RConsEI Project Director, Mott MacDonald Ireland JOE SHINKWIN, BE, CEng, MIEI, DipMechEng Project Manager, Mott MacDonald Ireland Presented to a meeting of the Cork Region of Engineers Ireland 23rd February 2010 SYNOPSIS The N25 Waterford Bypass comprises a 16.3 km of dual carriageway bypass of Waterford City, 9.5 km of major link roads and an additional 13 km of side roads. It includes a 465 metre long dual carriageway cable-stayed bridge over the River Suir (with a 230m main span), plus a number of major viaduct and grade separated interchange structures totalling over 50 bridges. This paper describes the development of the current route for the N25 Waterford Bypass including the various phases of route selection. It deals with the project’s inclusion as a pilot PPP project and the development of the PPP contract. It follows the project through the statutory processes (including the discovery of Viking remains and the need to find a new route around the designated national monument site in Woodstown). The paper also describes the selection of the chosen bridge type for the Suir River Crossing and looks at some of the other major structures. Finally, the paper will briefly describe the construction contract and various aspects of construction. 1 MURPHY and SHINKWIN INTRODUCTION crossing of the Suir in the Waterford viii) were evaluated without area would impose costs on, and quantification while items v), vi), and vii) The need for a second river crossing of produce benefits for, the community at were derived in the process of the the River Suir in Waterford has been large. Such a crossing would be preliminary designs for the different recognised over many years. For justified if the benefits that it produced options. example, the need was put forward in exceeded their associated costs, and did the 1967 Development Plan by the then so by more than would be the case for The traffic modelling began with the City Engineer and since that time, a any alternative investment of the same extraction and analysis of the raw data second crossing together with approach funds. from a 12-hour Origin & Destination roads has been included in the City & surveys carried out at 18 sites in County Development Plans, (though the The benefits that could arise from a new Waterford in September 1994 by the original location selected was closer to river crossing include: Local Authority Working Group. Peak the city). hour and typical Offpeak hour matrices i) travel cost savings enjoyed by motor were derived using “sparse matrix filling vehicles and their occupants, This paper describes the development of techniques” and a gravity distribution ii) increased travel opportunities arising the current route for the N25 Waterford model was then calibrated so that only from improvement of the local Bypass including the various phases of the input of the zonal trip end totals highway network, route selection. It deals with the (rather than all the details of the trip iii) stimulation of the local economy by project’s inclusion as a pilot PPP project matrix) was required to allow a “variable” increasing its potential to attract and the development of the PPP matrix to be “synthesised”. After commerce, trade and industry to the contract. It follows the project through assignment of the “synthesised” trip area, the statutory processes (including the matrices, the resulting flows were iv) positive environmental impacts of the discovery of Viking remains and the compared with actual flows on key links crossing. need to find a new route around the and revealed a worst case fit of 10%. Projections of the trip ends for two designated national monument site in The costs that might be associated with horizon years (2006 & 2016) were Woodstown). The bypass includes an these benefits include: iconic cable stayed structure crossing prepared taking into account existing trip the River Suir and the paper describes v) the capital, land, and property ends as well as projections of land use, the selection of the chosen bridge type acquisition costs of the crossing and population, employment, development, and the issues associated with it. It also its associated roadworks, car ownership, etc. This, in turn, allowed deals with some of the other major vi) the annual operating and variable trip matrices to be created. This structures among over 60 structures on maintenance costs of the crossing, was an important facet of the study in the bypass. Finally, the paper will briefly vii) costs associated with the protection that the numbers of trips to and from describe the construction contract and of river navigation, different zones varied depending on the various aspects of construction. viii) negative environmental impacts of links between the zones which allowed a the crossing. more realistic evaluation of alternatives The N25 Waterford Bypass is included for two horizon years - 2006 and 2016. in the National Development Plan and is Evaluation Methodology part of Transport 21. The N25 (part of Alternative Crossings and Road the E30 Euro Route) connects Cork at The costs and benefits were quantified Networks one end to the port of Rosslare at the and evaluated during the course of the other end, via Waterford City. The study. Items i) and ii) were derived from Suggestions for possible river crossing original route at Waterford went right traffic modelling which utilised a sites were sought during the early through the city, travelling along the computerised behavioural transportation stages of the study. Fourteen potential congested city quays and crossing the model. The actual modelling suite used sites - variously suggested by the City River Suir over Rice Bridge - an opening was the DELTRAN suite of programs Council, the two County Councils, the span bridge which is required to open for (including a set of survey analysis NRA, the Consultant and the general shipping. The existing traffic volumes programmes). Item iii) arises from land public - were identified. and the anticipated growth in traffic use growth forecasts which were used clearly indicated that a new bypass and as inputs to the model. Items iv) and A comprehensive network of approach crossing of the river was needed. FEASIBILITY STUDY Background In March 1996, Mott MacDonald Ireland (then known as Ewbank Preece O hEocha) were appointed as Consulting Engineers to undertake a feasibility study in relation to the need for, and potential type and location of, a second river crossing and associated roads at Waterford. The Feasibility Study set out to identify feasible routes and crossing locations, evaluate and quantify the costs and benefits associated with these schemes, recommend a new crossing and approach roads, and examine the justification of the scheme. A new Fig 1: Alternative Routes Evaluated 2 WATERFORD BYPASS roads and other link roads was Feasibility Study Conclusions Report. Subsequent to the publishing of developed (See Figure 1). The principal the Waterford Second River Crossing objective of the Study was to identify the The need for a Second River Crossing & Feasibility Study Report, a decision was best overall solution to the different Bypass was clearly established having taken to extend the Waterford Bypass by needs of local traffic and people in regard to traffic performance, benefits adding a bypass of Kilmeadan. This Waterford, and those of long-distance and economic return. Having assessed decision was taken in view of the poor high-speed National Primary Road and evaluated a large number of standard of the existing approach traffic. It was thus necessary to test networks a recommended road network through Kilmeadan to the proposed potential new crossings, with different was selected, taking account of bypass. The scheme was also extended combinations of approach roads, and in economic rate of return, Waterford City at the northern end. Refer to Figure 2. combination with other new crossings traffic performance, National Primary (and associated approach roads). In Route traffic performance, outline Road Type total one hundred and five alternative environmental examination, and the road networks were tested and projected development of Waterford City In 1999 a further set of model runs were evaluated. and environs. The recommended undertaken for the “Design Year” (then scheme had an internal rate of return of selected as 2025) using new trip ends Environmental Assessment of around 20% which confirmed the need which would take account of the Different Route Options for the scheme. The selected network additional trip potential arising from the comprised: fact that the new network of roads would The route segments were selected to lead to changes in development policies minimise known adverse potential i. a new road bridge across the Suir and trends. At the same time, the model environmental impacts where possible. between Gracedieu and Grannagh, network was extended to the west to An outline environmental assessment ii. a new approach road to the south include Kilmeadan. was carried out on each route. This end of the bridge from the N25 at assessment covered the following Dooneen (subsequently extended to The 2025 daily traffic volumes resulting categories: Mathews Cross to bypass from this analysis in AADT vehicles were Kilmeadan), with an intermediate as follows: • Impact on buildings. access near Knockhouse Upper, • Impact on environmentally sensitive iii. an at-grade link road from the Kilmeadan Bypass 14,629 areas - areas of scenic beauty, Knockhouse Upper interchange to Western Bypass specific heritage areas, areas of the Cork Road/Southern Ring Road /Suir River Crossing 35,237 special scientific interest, and special intersection, with intermediate Northern Bypass 18,495 landscape control zones. access as required in the context of Western Link 31,918 • Land Quality - quality of agricultural planning for the area, or development land iv.

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