Project Details
Eurovia Contracting contacted us to undertake a 3D utility survey of an area of Coventry City Centre. The survey was to conform to PAS:128 with a 3D AutoCAD model and IFC files as the deliverable. The IFC files were integrated with both Eurovia’s 3D model visualisation tool (Aconex) and their in house AR solution (AVUS) to show live, the detected utility locations on site.
People
The works were planned by our industry expert in utility mapping surveys and undertaken by our experienced subsurface mapping department.
Process
Engage
A number of companies were contacted to tender for this project but it was secured by Murphy Geospatial, based on both price, quality and our track record for these surveys.
Plan
From instruction, a site visit was undertaken by our lead surveyor for the works. This site visit allowed the team to best prepare for the survey. The site was in the middle of a large shopping plaza and had significant foot fall. Following the site visit, it was found that most of the key areas and manholes to be lifted were accessible during the day, however, some early shifts were required in order to lift some inspection chambers in high trafficked areas.
Execute
The GPR survey was undertaken using an IDS Stream C GPR System. This allowed for comprehensive coverage using the systems dual polarised 600MHz antennas. All collected GPR data was recorded and analysed at our offices. Post-processing of the data improves its interpretation by resolving weak and intermittent signals and analysing multiple targets. This allows us to gain a better understanding of areas of complex or more obscure utility networks. In addition, there is the added advantage of acquiring a digital record of what work was carried out in the field. All processing of GPR data was carried out by a qualified geophysicists to ensure all GPR data is correctly and thoroughly interrogated.
Complex communications inspection cover with numerous ducts and cables within.
All inspection covers and manholes in and around the survey area were lifted, their contents detailed and all services running through them were traced using electromagnetic survey methods. This included a deep and complex communications inspection cover that had a tangle of cables and fibreoptic. Using the range of tools from flexi-traces and GPR, it was possible to fully map out the routes of the ducts and services within.
Where services were traced, marks were sprayed on the ground using temporary paint to indicate their position. All paint was colour coded to allow easy identification of services to those on site. The locations of all services were topographically mapped using a total station and existing site control. Where control was not present, this was installed by the survey team.
Deliver
A key aspect of the works was that the results needed to be as a 3D model with each service extracted as an IFC model, with metadata, to be viewed through the client’s AR and BIM model. Each of the client’s 3 or 4 person construction teams on site have been issued with tablets allowing them to viewing the utility plan in 3D with the additional metadata. The AR system (AVUS) is used by their machine operators.
As all the site data was collected using the existing control on site, it was possible to produce a complex 3D model with metadata built in for each service. The model has all services accurately positioned with x, y and z coordinates, including their diameters and type details in the metadata. This was all positioned on to a provided 3D topographic survey and provided to the client along with IFC files for all the services. The client was then able to overlay this with the design and existing ground level models for clash detection and visualisation of the construction works.
Review
The client is constantly reviewing the way they use IFC data, and Murphy Geospatial, working with the client, developed a revised workflow for their production, from site to office, that has now been adopted by the client for all future projects.
Technology
Using the latest technology in ground penetrating radar, our utility survey teams can detect and map the location of utilities such as pipes, cables, ducts, sewers as well as underground structures and chambers to PAS128 standards. Maps can be produced in 2D or 3D wireframe and model drawings, GIS outputs, geo-referenced manhole photography, longitudinal sections and cross-sectional views of pipework and other detailed reports.
Contact
To find how we can support your project and for more information about our PAS128 utility survey solutions, check out our website and contact Andy Kitson, our Geospatial Consultant on 0203 598 3775 or via email akitson@murphygs.com
