A C T

A Bridge for Active Travel

TypeBridge, Greenway
LocationBallyforan, Roscommon, Ireland
Year2023
StatusConcept Design
Size3,500 m2

With the goal of establishing a safe pedestrian and cycle route from the village of Ballyforan and the Peatlands Restoration Greenway Loop, ACT studied three scenarios for crossing the River Suck. These scenarios consider using the existing Ballyforan Bridge, adding a new parallel bridge dedicated to active travel and adding a new bridge that would run diagonal to the existing.

The existing crossing

The current traffic crossing across the Suck is the Ballyforan Bridge, a thirteen-arch road bridge, built c.1820. This is a protected structure consisting of coursed stone wall construction, cut limestone voussoirs to segmental arch-rings, V-cutwaters up and down stream and cast-iron tie-bars. The bridge clear width is narrow (C.5m) making crossing with two-way traffic difficult.

Ballyforan developed around a taxing bridge over the River Suck. Since 1820 this has been a thirteen arch bridge which is still in use today.
Ballyforan Bridge

Ballyforan developed around a taxing bridge over the River Suck. Since 1820 this has been a thirteen arch bridge which is still in use today.

In modern times the amount and size of the vehicle using the bridge has increased making it dangerous for pedestrians and bicycles.
Increased traffic

In modern times the amount and size of the vehicle using the bridge has increased making it dangerous for pedestrians and bicycles.

The bridge reduces the width of the road to less than the requirement for two lanes effectively forcing it to operate as one lane over the crossing.
A narrow crossing

The bridge reduces the width of the road to less than the requirement for two lanes effectively forcing it to operate as one lane over the crossing.

The scenarios

In collaboration with engineers MFA three approaches were explored to provide safe pedestrian and cycle crossing of the Suck, using the existing bridge, cantilevering from the existing bridge and building a new bridge. From the initial explorations, cantilevering was discounted for structural reasons and a total of three options across using the existing and building new were further developed. 

The approaches

A new parallel bridge - Option 1

A new bridge parallel to the existing would offer segregated flows from traffic and pedestrian/cycle routes. This would allow the existing bridge to operate as it is currently and pedestrian/cycle flows to operate safely with more generous space. Running parallel to the existing bridge is the shortest route and the cheapest for crossing. This will however obstruct the proposed marina design with limited head room to go below the new bridge.

A new diagonal bridge - Option 2

A new bridge diagonal to the existing would offer segregated flows from traffic and pedestrian/cycle routes. This would allow the existing bridge to operate as it is currently and pedestrian/cycle flows to operate safely with more generous space. Running diagonally to the existing bridge, will avoid obstruction of the proposed marina design and will avoid visually obstruction of the view of the existing bridge from the marina.

Sharing the existing - Option 3

This solution is implemented by installation of traffic lights on each side of a bridge, narrowing traffic to one lane over the bridge and providing a designated zone for cyclists and pedestrians to cross freely. The narrow nature of the bridge excludes space for a buffer between the traffic and cycle/pedestrian space. The one way traffic will require vehicles to stop on one side while the other passes which at certain times may cause tail backs.

Team

Concept Design
  • Inna Stryzhak
  • Kevin Loftus

Collaborators

Structural Engineer
  • MFA

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