New footbridge in Hampton, Evesham
Introduction:
To support design of a proposed footbridge development, ESP reviewed, supervised, implemented and reported an investigation at this complex site in accordance with BS:5930, BS:10175.
The various challenges required meticulous planning and included pre-commencement discussions with the Client, the Designer and ESP to ensure all parties were satisfied with the work activities and health and safety requirements. The successful ground investigation provided the basis of a detailed ground model and supported foundation design optioneering for the proposed footbridge.
Details:
We were engaged by Burroughs and Alun Griffiths Contractors on behalf of Worcestershire County Council to undertake a multi faceted ground investigation to support design of a proposed new footbridge and associated pathways in Hampton, Evesham. The proposed scheme includes a bridge across the River Avon, a causeway across the flood plain, and new shared walking and cycling paths to provide a safe and direct foot/cycle connection between Pershore Road to Evesham town center.
A previous desk study and preliminary risk assessment were reviewed by ESP as part of site planning and preparation to identify any data gaps. The site is formed of various complex geological, ecological and geomorphological hazards and comprises the land to the east and west of the River Avon, where on the west the ground is steeply sloping to the river. The underlying geology is variable across the eastern and western banks for the river, with the Wasperton Sand and Gravel Member, over Alluvium overlying bedrock comprising Blue Lias Formation and Charmouth Mudstone. To the west, no superficial deposits are recorded and the site is directly underlain by Rugby Member (Limestone) bedrock.
A site investigation was undertaken to determine the underlying ground conditions and support development design. The investigation was designed to navigate the complex site access and steep slopes, with slope climbing rigs utilised to undertake the rotary boreholes.
In addition, the development is proposed on sensitive land with ecological restrictions including tree protection zones, presence of Himalayan Balsam, and close proximity to the ecologically important River Avon (SAC, SPA and RAMSAR). In order to ensure protection of the river, silt fences were installed along the river banks.
Access to the majority of the site was gained primarily via public rights of way (footpaths) or private land. Pre-commencement Client and land-owner liaison formed an important aspect of the project.
A view over the River Avon as ESP undertake a complex ground investigation in relation to the proposed Hampton Footbridge at Evesham. Our team is now on site following some challenging logistical planning with limited site access, steep slopes and numerous ecological constraints. pic.twitter.com/8y3hOZ8exV
— Earth Science Partnership (@ESPLtd1) September 15, 2022
The site investigation, comprising trial pitting, cable and rotary boreholes, windowless sampler boreholes and concrete coring, was undertaken in 2022 in accordance with BS5930. Continual communication between ESP, the Designer and the Client was key to successfully implementing the investigation, particularly with challenging site and ground conditions. Our investigation allowed for the refinement of the Conceptual Ground Model to support development design.