A430 and A417 Gloucester Bridge Maintenance

Town Ham Viaduct (ST1127)

Town Ham Viaduct is an eight-span, twin-deck structure built in 1973 that carries the A417 over the floodplain, a designated conservation area and the South Wales Main Line railway. The bridge comprises a reinforced concrete deck supported by painted steel girders, with substructure elements founded on piles.

Over time, significant water ingress through the bridge's movement joints has resulted in deterioration of the structure. This has led to cracking, delamination and concrete spalling within the substructure, exposing structural elements to further deterioration. Continued leakage is accelerating these defects and increasing the need for maintenance interventions to preserve the bridge's long-term integrity and serviceability.

Portham Floodspan (ST1126)

Portham Floodspan is a 60-metre-long, three-span twin-deck bridge constructed in 1974. It carries the A417 over the River Severn and surrounding floodplain. The structure comprises prestressed concrete beams supporting a reinforced concrete deck, with reinforced concrete piers and abutments founded on piles.

The bridge is experiencing deterioration associated with water leakage through deck movement joints. This is causing concrete spalling to substructure elements, exposing reinforcement and increasing the risk of corrosion. Leakage is also contributing to corrosion of bridge bearings, which are essential for accommodating movement within the structure. Addressing these issues is important to maintain the bridge's performance and resilience.

Castlemeads Bridge (ST1274)

Castlemeads Bridge is a two-span semi-integral bridge built in 2002 that carries the A430 over the River Severn and adjacent floodplain. The bridge consists of a reinforced concrete deck supported by painted steel girders, with piled foundations supporting the structure.

Although relatively modern, aspects of the bridge's original design and construction have contributed to the early deterioration of key components, including bearings, movement joints and road surfacing. These issues are resulting in increased maintenance requirements and are affecting the long-term performance of the structure. Planned works will help address these defects and ensure the bridge continues to operate safely and efficiently as part of Gloucestershire's highway network.