Flood damage to an unclassified road requiring repair and strengthening of its single span natural stone arch

Flood damage the unclassified road bridge in Merthyr Tydfil, Wales

The client: Merthyr Tydfil County Borough Council

The bridge is a single span segmental stone arch with a clear square span of 3.5m. It comprises a natural stone arch and abutments on spread foundations and carries the unclassified Pentwyn Deintyr road over the Nant Mafon Brook.

The flood damage problem

The bridge had suffered from severe flood damage. The spandrel walls had been severely damaged and a large bulge had formed in the barrel of the arch.

The Goldhawk solution

Following analysis using ASSARC assessment a repair scheme was devised using MARSYS. The fill over the barrel was removed and the bulging area of the barrel was jacked back into shape. The MARS System was installed and stainless steel anchors were additionally installed through the barrel into a new reinforced concrete backing. Works were completed within the scheduled five weeks, including repairs to the parapet walls.

Flood damage repair to a single span natural stone arch

Flood damage to the unclassified road bridge

Extensive flood damage caused the spandrel walls to collapse

Flood damage created this bulge in the bridge barrel

A bulge in the barrel

A large bulge had formed in the barrel of the arch

The bridge barrel is jacked in to shape by the team at Goldhawk Bridge Restoration

Jacking the barrel

The Goldhawk team removed the fill over the barrel and jacked the bulging arch back into shape.

Goldhawk Bridge Restoration’s MARS system is installed at Merthyr Tydfil

The MARS system

Additional stainless steel anchors were installed alongside the MARS system into new reinforced concrete backing.

Goldhawk Bridge Restoration finish the parapet with close attention to detail

Finishing and reopening the road

The repairs and strengthening left the visual appearance virtually unaltered and allowed the bridge to be opened to unrestricted two way traffic.