Newlands Cross Upgrade EIS - European Investment Bank

South Dublin County Council N7 Newlands Cross Upgrade
Environmental Impact Statement
Arup Consulting Engineers
4.2.5.5 Belgard Road
The existing wide grassed median will be reduced to a 0.5 m wide minimum concrete median.
A parallel service road will relocate the private direct access for “Moreen” to the new
signalised junction for the Golf Club. This junction will also provide safe access to Belgard
Road to the 10 no. houses on the old Belgard Road. The design of the junction can readily
accommodate a future Metro in this area, with the Metro likely to cross from the northeast
side of the junction to the median through the junction. Consistent with elsewhere on the
scheme, all lane widths are 3.2 m. The road geometry in this area has been devised to limit
the amount of third party land acquisition, with almost all the road improvement works
occurring within the road curtilage.
4.2.6 Bridge Structure
The proposed flyover structure at Newlands Cross is a two span prestressed concrete integral
bridge deck,. A central pier is to be located within the traffic island which separates
northbound and southbound traffic through the junction on the R113 Belgard Road. The
recommended method of constructing the approach embankments to the bridge is to adopt
reinforced soil with modular split stone block facing panels. The structure shall be designed
for a 120 year design life
It is proposed that the bridge abutment and intermediate pier foundations consist of reinforced
concrete spread or pad footings founded on top of the competent limestone bedrock which is
estimated to be approximately 3m to 4m below existing ground.
It is anticipated that a high containment kerb will be required around the base of the
intermediate pier traffic island to redirect vehicles and significantly reduce the risk of collision
with the intermediate pier.
A hard landscaping design with effective lighting will be required beneath the bridge deck to
provide a safe and comfortable environment for pedestrians and cyclists.
4.2.7 Traffic Signs
The proposed upgrade of Newlands Cross will require large verge mounted advance direction
signs, overhead portal gantry signs and cantilever gantry signs. The design and positioning of
these signs will be in accordance with current NRA standard practice. Some of the signs will
be positioned outside the extent of the road upgrade works and their supports can be placed
within the road curtailage. Allowance has been made in the proposed scheme for the
positioning of large sign supports.
4.2.8 Safety Fencing and Barriers
Safety Fences and Barriers are proposed at locations as required under the NRA DMRB.
Road edges on embankment supports to large signs and structures will have appropriate
protection. The adoption of a narrow median requires the use of a concrete median barrier on
the N7 mainline. All kerbing along the N7 mainline west of Newlands Cross and on the
reinforced earth elevated section, will have a chamfered 75mm upstand to mitigate against the
possibility of errant vehicles being launched by the kerb.
For this scheme, the mainline vertical geometry provides scope for construction of at grade on
and off ramps on both side of the junction location. Thus the requirement for vehicle safety
barriers is minimised along the ramps.
The existing boundary treatment has been retained as far as practicable throughout the
scheme. A stone faced pre-cast concrete wall mostly of 1.3m height is proposed along
northern and southern part of N7. A 2m high stone faced pre-cast concrete wall is also
December 2007 Page 71