Helicopter landing platforms for routine and emergency operations are a vital part of any offshore operation and must be able to withstand harsh marine environments with minimal maintenance. Helideck specialist Bayards explains why Tekla's intelligent 3D-modelling software was their choice for an extremely demanding industry.
Netherlands-based Bayards has designed and built helidecks for more than three decades. Its products are used not only on offshore vessels and platforms, but also across Europe for trauma aircraft bringing patients to hospitals.
The firm's aluminium decks can be half the weight of their steel equivalents, and enjoy the added advantages of corrosion resistance and low maintenance during their 30-year-minimum lifespans. For the entire process - from design and engineering to fabrication and installation of the aluminium helidecks - Bayards chose Tekla's intelligent 3D-modelling software to guarantee efficiency, high quality and system flexibility, and to enhance communication and coordination across and between projects.
"Tekla offers certain efficiency for the type of structures that we build," says Albert Hogewoning, technical director at Bayards. "Tekla models and drawings comply with the quality demands and expectations of our clients, particularly in the offshore market, and that is of key importance."
Designing a helideck at Bayards typically begins with a few initial outlines that are quickly transformed into more sophisticated virtual 3D models. Engineering design and analysis systems are then used to evaluate the loads and reactions of the structure based on the anticipated aircraft type, regulatory requirements and its connection to the supporting structure beneath the deck.
An offshore helideck incorporates a landing surface, trusses, platforms and stairs, along with lighting, tie-down points and firefighting equipment.
"We prefer to model everything in detail with Tekla Structures - even the fire extinguishers and the tie wrap connecting them to the helideck," says Wim Vergouwen, senior engineer at Bayards. "As with aluminium, every specific item must be extruded; we have to order the material before we start the fabrication part of the project.
"That is why we create a rough model in Tekla for material quantity take-off, after which our purchasing department can buy all the alloys and extrusions," he adds.
"We also use the model to accurately determine the total weight and centre of gravity of every structure," says Taco Blok, project manager at Bayards. "We have tested it quite often, and it has always been correct."
Before choosing Tekla, the company's engineering department was using different 2D and 3D methods. However, the resulting models were often too complex or error-prone, and files were very large, requiring significant computing power.
"The set-up of the engineering and the way of working with a 3D model is different to using 2D computer-aided design. It's much faster and gives better understanding, which helps us and our clients," said Blok.
The engineers at Bayards can quickly and easily develop project-specific aluminium profiles and parts that are customised to suit customers' unique helideck requirements. Since implementing Tekla, Bayards has developed an extensive object library of aluminium profiles with different alloys and specialised bolt assemblies.
Customisable software makes this possible - for example, by supporting creation of company-specific libraries.
"We particularly like Tekla's made-to-measure profiles," says Vergouwen. "Tekla handles non-standard objects as profiles more easily than others. We can build simple or complex profiles."
Bayards also values the local support that Construsoft, the local Tekla reseller, provides during and after implementation of the solution.
Once a helideck is designed in Tekla, the constructible model is sent to the Bayards workshop, where the rich model information is used to fabricate components using CNC machines. The tolerances are extremely narrow: bolt holes, for instance, are accurate to within 0.3mm.
"The model and progress reports assure clients that their projects are moving along as expected," says Blok. "The professional relationship is now considerably different. In the old days, 2D drawings were used; now, preliminary models are sent to clients so that they know exactly what they are going to get and what the finished product will look like. Tekla models provide visual assurance and help avoid misunderstandings during assembly, all of which contributes to very satisfied customers."
"We have two ways of delivering helidecks," explains Blok. "The first is the turnkey approach, in which we fully assemble helidecks in the workshop. It is like a plug-and-play system: the crew bolts it to the ship, and connects the cabling and piping to run some tests, after which the project is finished."
"The second way is delivering the product as an assembly kit. All items are packed into two or three 40ft containers so that the helideck can be assembled on sites all over the world, guided by our experienced supervisors."
With the as-built model on a tablet, the supervisor has all the information needed to support the assembly. Regardless of however the helidecks are delivered to customers, all parts are prefabricated to a specified size, including bolt patterns, and are virtually assembled beforehand using the 3D technology to ensure a smooth and fast assembly on site. This eliminates errors such as the shipping of wrong parts or not having the correct quantities of components on site.
"Bayards makes flatpack-type packages of complex engineered products down to the last bolt, nut and washer," explains Hogewoning. Every helideck design is built in virtual reality first to ensure that once the kit gets to the site, everything fits and can be installed quickly and easily. The virtual process surprises many of our customers, but it works, and it saves lot of money and time."
Bayards's helidecks have been installed everywhere from the North Sea to the Caribbean; at any given time, between ten and 20 are under construction around the world. The assembly teams use Tekla BIMsight and Tekla Field3D for coordination on site.
"The benefit of using the model on site is that our team is able to visualise detailed connections and components in 3D. We can pull measurements from the model, verify connections and so on. We also use the model to support client meetings," says Blok.
Hogewoning's view is that Tekla has benefitted Bayards's relationship with clients, not least in the tendering process.
"Coordination has helped to improve project delivery times," he says. "Bayards is able to bring up the full, detailed 3D model of the project and look closely at the areas in question, knowing that the model has been built to precise measurements. Customers leave meetings knowing that they are working with a trusted company that is in complete control of the process at all levels; having a 3D model available has certainly contributed to that."
With Tekla Field3D, project managers can show models on tablets and explain to local assembly crews - many of whom won't have seen a helideck before - exactly what they are building and where the various parts belong.
There is, however, room for personal preferences, according to Hogewoning: "I like the iPad because it's so easy to handle, but some of our engineers use Tekla BIMsight on PC and are very keen on it."