BIM: A boost for Christchurch in post-earthquake rebuild
Building Information Modelling, better known as BIM, is the future of the construction industry. In basic terms, using BIM, a building is digitally designed from the ground up in three dimensions (3D). The major players – contractors and designers, architects and engineers – work using one data platform, one common language, one 3D design.
The fundamental building blocks are the same for every project, even if the overlays are changed to suit specific buildings. Think of it like gigantic virtual Lego pieces: at the heart of our BIM system, we have a series of very common Lego blocks that form the core of the design. Then, like Lego, we assemble these blocks into sets – we make a hospital set, an airport set, a prison set, a commercial building set.
A hospital set is healthcare focused, so elements like light and air quality will have priority; a prison set will focus on security and safety; an airport set will have inbuilt systems for retail opportunities and information areas. Despite having unique components and requirements, they’re all built from the same base.
The implications of BIM change everything. Under the old system, buildings were assembled piecemeal, which forces construction workers to work from unsafe places – on scaffolding, on top of rafters, in difficult, dangerous positions. With BIM, there are better options to pre-manufacture, because there’s more certainty about the overall project.
And it’s not just the design process that has been revolutionised. BIM has also changed the way that contractors construct buildings. Builders on-site can use a tablet computer to view the BIM plan as a digital overlay on top of what they are physically seeing, similar to the ‘augmented reality’ of Hollywood special effects, but with a construction focus.
Once the building walls have been constructed, a laser grid that is accurate down to a millimetre is projected onto the surfaces inside the space, so workers can overlay the BIM to see exactly where the plumbing and electrical fixtures are to be located.
When you have this level of certainty and sophisticated technology, you can manufacture complex parts of the building in a controlled factory environment and then transport these to site. You can also investigate options for modularisation, which allows contractors to use workforces that are not necessarily based locally – in this case, in Christchurch, so they can deliver projects on time and on budget. This is particularly useful when resources in Christchurch are already stretched and limited.
BIM makes for three-way savings: in design, construction and for future planning. Savings in design relates to collaboration and helps with more certainty around design, which enables the client and contractor to forecast budgets more accurately with relation to time and works on-site. Once construction begins, the client gets the benefits of set-out time and of health and safety, plus the benefits of more accurate and timely material deliveries. There are also benefits concerning future expansion of the project, as you have a more accurate and convenient record of the location of services.
In fact, working on a project in this way improves efficiency in many ways. Before we had an integrated system, identifying design conflicts was difficult and when issues came to light in later phases, they were harder and more costly to resolve.
The decision-making process when using BIM is quicker because you are digitally prototyping the building before it gets built, which means that businesses get certainty on costs, timings and progress much sooner. There is more accuracy when ordering materials, with installation times and also in relation to savings based on hours of installation. For instance, in the Christchurch Justice and Emergency Services Precinct (CJESP), we recently installed around 42,000 Blue Bangers or seismic anchors. Typically in the construction process, hanging anchors are drilled after concrete has been poured, but by using a proprietary product such as Blue Bangers, building services can be hung off pre-installed fixing points that have been set out from the BIM, thus providing safer working conditions for contractors.
BIM was particularly useful after the earthquakes to capture existing buildings such as the Christchurch Art Gallery, when the building’s foundations were severely damaged during the earthquake. After capturing the information, the building was propped up, severed from its foundations and base isolators were installed to ensure that the building will ‘float’ during future earthquakes.
We are working on several large-scale sites in Christchurch, including the CJESP and we are also currently using BIM for the Acute Services Building at Christchurch Hospital.
Early enabling work has started at the Acute Services Building and major construction will begin later in the year on this 62,000-square metre project. There are special challenges when designing and constructing hospitals, such as servicing the specialist medical equipment, with cross-contamination and infection control, and also with the complexity of medical gases.
A lot of people who visit a hospital site take all the equipment and services connected to the bed for granted, but getting all those services to the back of the bedhead is quite a skill. That is where BIM comes into its own. Being able to pre-plan and optimise all those building services is really critical, especially when you start to cross-reference with ventilation and reticulation.
BIM is also invaluable for planning future scenarios, such as epidemics. Recently, a suspected ebola patient was flown into Christchurch Hospital. Being able to know what kind of quarantine procedures you need to put in place is invaluable for future-proofing operational procedures around infection control, outbreaks and disasters such as earthquakes.
Anecdotal evidence shows that BIM can save upwards of 20 percent on-site during construction. Estimates that have been tested on-site show that you can save up to 50 percent on the installation time on-site by using digital set-out, compared with traditional set-outs.
BIM helps businesses get a return on their capital by allowing them to monitor and assess the performance of their facility from energy analysis through to operational procedures. Additionally, because the work takes place within a common digital environment, all information can be shared and the project can be worked on simultaneously and in real time.
For every dollar that’s spent on design, another $10 is spent on construction, and another $100 is spent on the running of the project over its entire life cycle. If you can be more efficient in the operations of a building, you’ve done something magical. That’s what BIM is about: think of it as a long-term investment, not a short-term fix.
ANZ at forefront of BIM
New Zealand and Australia are at the forefront of BIM technology. The New Zealand Government has just started the BIM acceleration committee as part of an MBIE (Ministry of Business, Innovation and Employment)-funded productivity partnership with the goal of 20 percent more efficiency in the construction industry by 2020. Overseas, the UK Government has passed a mandate for the industry to be Level 2 BIM compliant by 2016.
Despite this, true experts in BIM are scarce and therefore are in very high demand.
At Warren and Mahoney we are developing our own BIM platform, built on international knowledge and best practice.
As technical BIM manager at Warren and Mahoney, under my direction we’re leveraging the combined expertise, using technologies and educating clients and colleagues about the benefits that can be reaped from these new work processes. There is also a sharing of digital models in real time with other consultants often across international borders. Thus, there is deeper engagement in the construction process by leveraging BIM on-site with contractors as projects evolve.
Within BIM lies an opportunity to revolutionise the industry on the back of technology that hasn’t existed to date.
The author Jason Howden is an international Building Information Modelling expert and has worked on BIM projects as diverse as the Royal Manchester Children’s Hospital, and on a 1.5-kilometre long terminal expansion at Jakarta Airport. He has relocated back to his home city, Christchurch, to specifically contribute to the rebuild as Building Information Modelling technical manager for architectural practice, Warren and Mahoney.