In today’s fast-track construction market, every contractor seeks to combine the best possible people and processes to deliver a project on time, on budget and with quality and accuracy.
When the project is a high-profile structure, the challenge can grow exponentially and so can the opportunities.
While working on a mixed-use development in Dubai, United Arab Emirates, Trans Gulf Electromechanical, the MEP arm of Al Naboodah Construction Group, sought to improve its transfer of design data to the field and back with help from new technologies, specifically robotic systems, as a way to improve speed and accuracy.
The development required the construction of four structures — a 10-storey office tower, 25-storey hotel, 25-storey residential tower, and 25-storey hotel/apartment tower as well as underground parking and a podium.
In 2015, Trans Gulf Electro Mechanical was awarded the contract for the supply and installation of the MEP systems and services for the entire project.
Chris Milford, BIM/CAD manager, who relies on Revit and Navisworks for 3D collaboration and coordination, says: “The client had not mandated the use of BIM on the Dubai project. But we’re always looking for ways to improve productivity and efficiency.”
With Milford’s skillset, Trans Gulf management decided that the MEP shop drawings for the project would be developed from a BIM model and issued according to a BIM execution plan developed specifically for the project. The long-term vision was to make the Bur Dubai project the first of many BIM projects for Trans Gulf.
“With the development of our in-house BIM capabilities, and as construction on the project developed, we saw an opportunity to save labour and reduce costs by implementing a BIM-to-jobsite process,” explains Milford. “In this scenario, the construction team would not only benefit from a fully coordinated MEP system, but also from the transition of the information and data we have stored in the model from the virtual design space to the jobsite where it can be of greater value to the project.”
A Trimble representative offered a possible solution with a Trimble Robotic Total Station (RTS) combined with Trimble Field Link for MEP construction layout software.
To demonstrate the potential benefits of the Trimble Field Link software and hardware solution, Milford set up a side-by-side comparative study between the automated RTS method and conventional practices on the lower level basement (B2) of one of the towers of the project.
Milford says: “As part of the demonstration, our installation crews needed to mark the bracket positions for the mechanical systems that would hang underneath the soffit.”
The B2 level comprises a built-up area of 11,650m2. Approximately, 7,000 points needed to be marked per car park level.
Using the conventional method, Milford set up three teams of three installers to manually locate support points from shop drawings, with measuring tape and physical markings. The process required a team of three using ladders and scaffolds to complete the process; for instance, reading drawings and setting out and marking each end of the tape.
Then, the Trimble team, which included one junior engineer and two operators, performed the same activity using the Trimble Field Link with a Trimble RTS. They uploaded the support points to the software from their model, and then moved around the site with one person running the RTS and two individuals marking points.
Milford says: “The results were eye-opening. In terms of productivity, the manual team was able to mark 156 points in about 48 hours. The Trimble Field Link team of three marked 210 points in four hours. Just as importantly, we’d proven that we can transfer BIM data to the field and use it to locate hangers, anchors, and sleeves with speed and accuracy. We could all see that we’d be more efficient, accurate and better able to meet the client’s deliverable schedule.”
Setting a new standard
Since procuring the RTS, Milford and his team have used the robotic system every day on the Dubai project. They use it to mark horizontal slab openings (electrical back boxes, drainage molds etc.) prior to the rebar installation and before the slab is poured.
Using the data contained within the BIM, Milford’s team is able to automate ductwork manufacturing schedules using SysQue, a specialised modelling tool that is accessible directly in a native Revit file, to locate support brackets, back boxes for lights and drainage openings in slabs, as well as providing point marks for builder’s work openings within the shear wall construction during the shuttering installation.
“Our ability to transition virtual data right to the jobsite allows us unparalleled accuracy and significantly reduces human error,” says Milford.
Trimble Field Link includes streamlined workflows to guide Trans Gulf crews through projects and improve consistency in layout and data collection.
“It lets us easily manage layout tasks with user-defined point lists and populate the lists with common layers and descriptions. We are able to produce layout deviations, daily point layout summaries, field reports and document daily production and existing conditions,” says Milford.
Milford hopes to buy more robotic total stations in the near future. He concludes by saying: “We’d like to use the one we have on all new projects. Our QA/QC procedures now include our BIM-to-Field process.”