The client purchased a brownfield site upon which a housing development was planned. Within the site, a reinforced concrete frame under croft was present, belonging to a third party.
As the under croft was owned by a third party, it could not be removed or filled. Therefore, the client required comprehensive information on the structure to determine its load-bearing capacity. This included reinforcement detail, construction thicknesses, and the compressive strength of concrete.
The structural details of the under croft were to be presented in a BIM environment, including the construction details of the elements within.
While access to the top slab was easy, the under croft itself was a low risk confined space and flooded. In order to obtain the required information, the under croft was constantly pumped out to allow our confined space trained teams to work within the area. A mobile elevated working platform was also used to reach the beams and soffit of the under croft.
Murphy Geospatial undertook extensive non-intrusive testing of the site using high-frequency ground penetrating radar (GPR). The GPR survey was undertaken on all exposed elements, including the slabs, walls, beams, and columns. This allowed us to accurately determine the reinforcement layouts, depths, and variations. Additionally, the GPR was used to determine the thickness of the wing walls.
Alongside the non-intrusive works 9 No. break outs were undertaken to determine the size and type of the reinforcement. 9 No. cores were also taken and tested in a UKAS accredited lab to determine the compressive strength of the concrete.
The whole structure, above and below ground, was laser scanned (tied to site control) to collect the data required for creating the BIM environment.
A BIM environment was created from the laser scan data by our in-house modelling team.
The Murphy Geospatial team undertook comprehensive processing and analysis of the GPR data and extracted the construction details from this. The construction information was combined with the intrusive data and was presented in a complete written report, including sample radargrams, CAD drawings, and testing certificates.
Additionally, the construction information was added into the BIM environment as metadata. This allowed the client to click on any element to see its construction details. This BIM allowed the client to calculate the exact load capacity of the under croft, and where it varied, as well as model how it would affect the works on site.
For more information on this project, please contact Andy Kitson at firstname.lastname@example.org or +44 203 598 3775