Northgate Steps, Chester City Wall
Overview
The Walls are a Scheduled Ancient Monument dating back to AD74, and the Northgate Steps is a Grade I Listed structure. Movement was detected in the structure of the Northgate Steps and in 2010, the Council propped then dismantled the steps as they were slowly rotating away from the walls and could collapse, leaving the stability of the walls reliant on significant temporary propping.
During previous dismantling work, complications with the archaeology below ground and the stability of the walls were revealed. The Northgate Steps were founded on the soft, organic Roman rampart material, which was once part of the original Roman Gate footings. The inner leaf of the city wall had been constructed on poor quality ancient rubble.
The works comprised:
- Piled foundations and concrete raft to support the rebuild of the steps and to underpin the inner leaf of the existing city wall
- Rebuild of the Northgate Steps, incorporating steel access chamber with power supply for future interpretation and lighting
- Repair of the inner face of the city wall, adjacent to the steps and construction of the new inner leaf behind the landing
- Rebuild of the core to the city wall over the extent of the landing (removed to facilitate removal of the steps)
- Incorporation of new hand railing with lighting to the rebuild
Key Challenges
- Working in close proximity to adjacent properties
- Buried services
- Restricted city centre site
- Construction traffic, site access and pedestrian management
- Lifting of heavy stones
- Working at height
- COVID-19 – Work activities were restructured to take into account the required social distancing measures and an increased sanitisation and cleaning regime was implemented. Consequently, EWCE were able to continue the works without delay and without any incident of COVID-19
The challenge at all times was to access the works within the temporary propping and undertake the stabilisation of the City Wall to prevent this ancient and delicate structure from collapsing.
Added Value
- The rebuild provided an opportunity to investigate previously unknown archaeological interfaces and allow the archaeologist to build on the information ascertained from historic investigations
- EWCE were engaged beyond the original contract to undertake considerable extra works including providing an illuminated hand rail to the steps, extra works to the footway on the wall and further investigation works to the wall