A construction clash with Tideway works has driven the cost of repairing Blackfriars bridge up by more than £3.5M.
A report to the City of London Corporation – which runs the London road bridge spanning the Thames – revealed that “access restrictions” due to Tideway construction has pushed the final cost of repair works up to £8.75M.
The report – carried out by Aecom – outlines that the need to work at night as well as complications caused by space on the north bank of the Thames has pushed costs up.
Repair works include a £4.8M paint job, as well as repairs to iron and steel sections of the structure.
The report outlines “a traditional scaffold” to “carry out the painting and refurbishment of a bridge” however it notes that “the parapet and spandrel will be affected by the Tideway works and will need to be coordinated with the Tideway contractor.”
The report adds: “With the northern foreshore occupied by the Tideway works there is very little land available for a Contractor to house their welfare units and store the necessary materials.”
The need to work beneath the bridge arches has also been identified as an issue with extra barges and cranes in place to carry out Tideway works – meaning works to the bridge must be taken at night to ensure river traffic flow during the day.
The additional Port of London Authority cost of undertaking works at night is £2,000 per night.
A spokesperson for Tideway said they were working with the City of London Corporation to find a resolution.
“Work at our Blackfriars site started in 2016 and it is a critical location for construction of the super sewer,” the spokesperson said. “At this location alone, we will stop more than half a million tonnes of sewage pouring into the River Thames each year.
“Due for completion by 2023, we will also be leaving behind a new area of riverside space for Londoners to enjoy. We are working closely with City of London to ensure they can deliver their project while we continue our critical work.”
Last month Tideway announced that “complex engineering challenges” at two sites including Blackfriars had forced Tideway’s parent company the Bazalgette Holding Group to introduce cost-cutting measures.
At Blackfriars, issues have been caused by the proximity of the site to two large Victorian gas mains.
Tideway is working closely with gas operator Cadent to investigate if the lines needed to be diverted to avoid damaging them. However, initial results from a damage assessment suggested that they may not require diversion, with final damage assessment results expected by the end of the year.
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