Their challenge:

To provide options for remedial underpinning of existing foundations or to enable the design of new foundations should demolition and construction of a new building take place. The existing building foundations were understood to have been compromised by recent structural alterations to an adjacent property, visible in structural defects inside the buildings.

The existing properties comprised a row of two storey terraced shops / apartments. Access and working room were constrained by limited width and height access, hardstanding and restricted interior working area.

Our solution:

To address the challenges faced in the project, the team worked with the client ahead of the investigation to advise on modifications to the structure to enable access and movement, including removal of doorways, widening of interior accessways and limited removal of flooring or ceiling areas to facilitate sufficient working room.

The ground investigation was carried out using a modified dynamic sample rig with reduced mast height which could be stripped down to facilitate access and working. Fume extraction and dust suppression were employed due to absence of electricity and ventilation in parts of the building. Appropriate samples were obtained in conjunction with in situ testing to a depth usually requiring a larger type of rig to obtain the necessary information for the potential new foundation option.

Scope of works included:

The team was appointed to complete the following package of works:

• Five interior boreholes to a depth of 10m
• Interior inspection pits of existing foundations
• Disturbed and undisturbed representative sampling
• Geotechnical and chemical laboratory testing
• Interpretive reporting

The results:

Through careful forward planning and execution, the team successfully completed the investigation within the designated time period. The results of the ground investigation and laboratory testing confirmed existing shallow ground conditions would not facilitate the remedial option to the existing foundations, and provided sufficient information at depth to inform the proposed foundation solution for demolition and construction of a new, five-storey development.

Testimonial:

“The team provided dialogue in modifying the initial scope of work to enable a solution which provided results to inform all options being considered, with those results providing sufficient information to obtain the necessary Planning Permission for the revised building plans and progress the development” – Developer