BCM Uses Innovative Solutions on the East Coast Mainline for Network Rail22nd September 2021
This 5-span masonry arch structure was originally built in the 1850s and widened at some point. The structure has been stabilised before with pattress plates and ties with some of the arches being loose-filled with soil to provide support. Due to the unusual way the structure had been widened in the past, BCM was subcontracted to undertake top-down installation of temporary ground support within the arches to prevent future movement in the backfill behind the wingwalls (which were being stabilised by piling by others).
As the 5-span viaduct located on the East Coast Mainline was slowly deteriorating this essential work was needed to keep the line open between Kings Cross and Shaftholme Junction for Network Rail to continue to provide a safe and reliable railway for passengers.
The wall was installed in 3 rows, with each row being underpinned as the excavation progressed downwards to leave the whole height supported. Once this is installed, the outer spans will be infilled with a combination of concrete, foam concrete, and grout to provide permanent support to the temporary wall, by surrounding it with cementitious material. The exposed face will be faced with matching brickwork.
As part of the concrete infill, BCM are required to installed 880 dowels, each 800mm long and grouted into a 35mm diameter hole. Due to the number of holes required, BCM employed innovative technology for the works by using a Positioner Actuator Manipulator (PAM). Traditional handheld tools would have involved exposure of workers to HAVS, with close monitoring of trigger times to maintain compliance. Utilising the PAM, it can be operated by a single operator as the arm takes the weight of the tool and almost all of the vibration, as demonstrated by the 8-hour trigger time for the PAM. The further advantage is that without down time or fatigue effect from holding the tool, productions with the PAM are significantly higher than using handheld tools.
As a business we are continuously looking for innovations to help drive efficiencies and safety on site.