About This Project
London-based residential developer Mount Anvil contracted Murphy Surveys to detect and locate post-tensioned tendons in the concrete slabs of the 27-storey Eagle House building in Central London, which they acquired as a stalled development site. The project comprises 276 new homes, 6312 m2 of commercial space, 36 parking spaces and a public square.
Following the acquisition, Mount Anvil needed to ascertain the positions of structural tendons in the reinforced concrete building. Murphy Surveys scanned the concrete floor-slabs, soffits and ceilings using the new Hilti PS 1000 X-Scan Detection System, in order to mark tendon positions with an accuracy of +/- 20mm.
Murphy Surveys is one of the first companies in the UK and the first in Ireland to invest in this recent technological innovation from Hilti. The scanner is designed to non-intrusively detect reinforcing bars, pre- and post tensioned tendons, metal pipes, plastic pipes, electric cables and glass-fibre cables in minutes, enabling an efficient and cost-effective survey. The radar detection system eliminates the need for drilling to locate rebars, and also enables safe drilling and coring for service cables and electrical ducting, thereby limiting the risk of costly mistakes. The system also offers an image-scan function, which shows the scanned structure in 2D or 3D on the device’s screen in real-time; this was particularly useful in areas where reinforcement mesh, tendons and other objects intersected.
The tendon locations were marked at intervals of two metres on the slabs and soffits, and surveyed by Leica Total Stations (TPS 1205 and TS09). With the use of control points in each floor, the positions were set out on the ceilings of the corresponding slabs.
Data was carefully examined and viewed with the Hilti PROFIS PS 1000 software, where all objects could be viewed three-dimensionally. All surveyed points forming the tendon lines were processed in a LISCAD environment and delivered as AutoCAD Civil 3D drawings to the client.
Structural Integrity Testing
Circa 200,000 sq ft
Hilti PS 1000 X-Scan Detection System