County Hall Wall

County Hall Wall

Beckett Rankine was approached by County Hall Estates Management Ltd (CHEM) regarding the Southbank river wall in front of County Hall which was built in the 1930s. The wall is a mass concrete gravity structure with a high quality granite block facing. A number of cracks had been reported along the wall and CHEM required Beckett Rankine to assess the severity of the cracking. During most states of the tide, much of the wall is obscured.

We carried out a detailed visual inspection survey of the wall to determine the condition of the wall. To ensure the full height of the wall was inspected the survey was carried out from the foreshore at low tide. Although even at low tide some areas of the wall were hidden below the water’s surface. The rising tide meant that we had a narrow working window, but the low water level allowed the identification of very low-level cracks, which could otherwise have been missed.

Low level crack
Low level crack

This survey was to act as a basis for any future surveys or work. All observed cracks and defects were catalogued and mapped to a local grid spanning the length of the wall. The landside section of the wall was also inspected.
Crack types ranged from hairline cracks to larger cracks where the blockwork had shifted throughout the full height of the wall. Although no severe issues were found, several cracks were observed which require monitoring. We prepared a monitoring plan together with a schedule of repairs.

Full wall height crack due to movement of blockwork
Full wall height crack due to movement of blockwork

This is a relatively modern frontage which is in good condition for its age. We regularly undertake assessments of historic frontages in much worse condition and design life extension works for them. Often the life extension is required to match the life of a new residential development being built behind the frontage which can be a challenge with a wall which may already be over 100 years old.