BIM is already gaining wider acceptance, but now contractors are beginning to see the benefits of using it with tablet devices in the field. Stephen Cousins reports. Illustration by Nick Higgins
If you’re looking for an inspiring vision of the future of UK construction, pay a visit to the London Bridge Redevelopment Project in central London. There’s not much building work to see, or indeed any new structures on site — principal works won’t begin until 2013. But hold up an iPad running main contractor Costain’s specially-developed augmented reality software and you will be able to see the soon-to-be-erected site hoardings and other temporary works on the screen, superimposed onto the camera view, as if they were real physical objects in front of you. Walk around site and the on-screen computer model updates in real-time, perfectly synchronised with the reality behind it.
This award-winning technology was created by games developer Inition to help reassure Costain’s client, Network Rail, that the planned structures will not impede its daily activities. It uses image recognition technology to work out precisely where the user is standing on the site and superimpose computer-generated images on top.
While today’s technology is a mobile version of architectural walk-throughs, tomorrow’s version will be able to pull images and information — such as M&E layouts, or as-yet-unbuilt internal walls — directly from the BIM model. (For a demonstration, type “augmented reality in construction” into YouTube.) And augmented reality is just one of a range of new mobile technologies that are set to take BIM models, previously confined to the office, out to live construction sites.
Given the pre-construction efficiencies released by BIM, it’s easy to lose sight of the huge benefits it can bring to the field. Giving site workers access to 3D plans and drawings on smart phones, iPads or other tablets eradicates the need for rolls of drawings and repeated trips to the site office. Meanwhile, as-built construction data can be gathered on sites and transmitted wirelessly to update BIM models in real time, improving their accuracy not just for design teams, but for construction and ultimately the operational phase of the building.
Successful planning
Contractors already sold on mobile BIM technology are finding it crucial to the successful planning and co-ordination of work, using it to access 3D models and related data, visualise the fourth dimension of time scheduling, carry out snagging, coordination and clash detection, and in the process save time and money and minimise risk.
“Field BIM has the capability to automate delivery processes and drive increased productivity for all project stakeholders,” says Chris Millard, business efficiency director at Balfour Beatty Construction UK, which is rolling out the technology on several UK sites including Heathrow Terminal 2B and the M4/M5 junction managed motorway projects.
“Using iPads to capture as-built data and channel it back into the BIM model we are able to visualise where the programme is versus where it should be and so plan construction more strategically over the next two-to-six weeks. As a result we have seen a 15% increase in productivity in site supervision tasks, which is a real win-win considering the price of implementing the technology is relatively inexpensive,” adds Millard.
Those unconvinced of how important Field BIM is becoming should consider the fact that this year Autodesk, the world’s biggest 3D construction software developer, bought construction field management software provider Vela Systems. Autodesk’s BIM 360 Field software is available to test in a 30-day free trial, accompanied by a free mobile app from the Apple App Store.
It’s still early days for Field BIM in the UK, but contractors including BAM, Costain and Balfour Beatty are all running pilot projects to test out its capabilities on various projects. Balfour Beatty recently partnered with Autodesk to provide BIM access to staff at the Terminal 2B and M4/M5 projects, hoping to drive efficiencies on the large sites, says Millard. “The benefits of mobile wireless access are best realised where geographically the distances between construction work and site offices are large,” he says.
Balfour’s site personnel use iPads running Autodesk BIM 360 Field to visualise 4D BIM models, take photographs, mark them up with comments and tag them with geospatial coordinates intended to communicate as-built information on underground services, drainage and more.
“It enables us to manage the project in an entirely different way,” says Millard. “Where previously the project team had to gaze at a maze of red and yellow lines and notes on a wall chart drawn up by the project manager, our as-built info is used to create a visual 4D BIM model that we can compare with the planned 4D model and so identify time and space conflicts and opportunities to improve productivity.”
QR codes
Meanwhile, paper documents, such as the health & safety plan or site quality inspection plan, are each printed with QR codes. When scanned on site using a tablet’s in-built camera, these automatically link to the latest version of the document, so that everyone on site is working from the same information.
Field-based barcode scanning is also being used in a new way in the US, where it is realising the long-held goal of tracking material production, delivery and installation. Skanska has used it to track the fabrication and delivery of 800 curtain wall panels that make up the patterned facade of the new James B Hunt Junior Library at North Carolina State University.
Each panel is unique in shape and had to be fitted in exactly the right order, so a system of individual barcodes was devised by Vela Systems and Skanska that enabled subcontractors to scan the panels using tablet PCs, fill out quality control checks and link the information back in real time to the Navisworks BIM model.
“It meant that during fabrication and installation we knew each unit’s precise location, quality issues, what parts and pieces would be on jobsite when, and we could reschedule adjacent works appropriately,” says Will Senner, senior project engineer at Skanska.
Skanska has also previously used radio-frequency identification (RFID) technology in a similar system. Realising the benefits of instant communication, Costain is rolling out BIM to the field on a central London site, where 20 iPads have been deployed to view the 4D Navisworks model and related information, and communicate snagging information back to the designers. The contractor is also investigating the use of mobile construction management software including BIM 360 Field, the BIM collaboration tool BIM 360 Glue, Bentley Navigator and Tekla BIM Sight to enable workers to capture as-built information and monitoring defects.
Wireless infrastructure is a key concern when considering a Field BIM deployment, says Matt Blackwell, group BIM manager at Costain: “Software such as BIM 360 Field relies on cloud computing over the internet to store the vast amounts of project data normally stored in servers, so a high-speed data connection is needed. It’s important to assess whether a site has good data coverage using 3G. If not, a Iocal wi-fi network might be required. Although it is possible to record field data offline and then synchronise it later on back at office, live data radically reduces the risk for error on a project,” he says.
Data security is another issue, in particular where information is sensitive and has to be locked down, as internet-based systems can be hacked into.
It’s also important to gauge the correct level of detail needed in an as-built BIM model, says Blackwell, focus in too closely on gathering data on every nut, bolt, and screw head and it won’t add value to the project and could even slow it down.
Laser scanners
The capture of as-built data in the field is also carried out using 3D laser scanners and point cloud software developed by the likes of Leica Geosystems, which have improved the efficiency of creating accurate and intelligent 3D models in BIM.
Laser-to-BIM software technology, such as PKNail, allows users to translate surveyed field measurements and building geometry directly from wireless laser range finders into a BIM workstation running Autodesk Revit, enabling users to create BIM models on site and in real time.
Revit is also harnessing BIM to directly automate vehicles and equipment in the field. Operators can load Revit’s 3D models into the on-board computer of a GPS-enabled bulldozer or excavator. Then, using a combination of GPS and on-site laser-based positioning systems, the operator can compare their real-time location with the current site model as the machine digs or fills etc.
Although human operators are still needed to drive the machines and manually adjust their course to the directions obtained through the GPS systems, as the technology improves, it’s not difficult to envision a time when full automation can be achieved.
“The sky’s the limit with BIM right now. In future everything will be fully transparent and accountable within the BIM model, from 4D time sequencing on site, product and materials ordering systems, RFID materials tracking of materials and the real time location of plant on site using GPS,” says Phil Palmer, virtual construction manager at BAM Construction, which has just started trialling Field BIM software on a project at Bradford College.
“It won’t be long before augmented reality on tablets will be fully bedded in, so, for example, if you want to locate a fan core unit under a completed suspended ceiling, you point your iPad camera at the ceiling and the M&E systems will be displayed in 3D on screen,” adds Palmer.
As Costain’s experiment with augmented reality at London Bridge proves, that future is not far away.
