Basler & Hofmann is using its own office building in Esslingen, in the canton of Zurich, to test out a systematically digitalised planning and construction process. In this way, the company is taking integral planning to a new level. Here is a glimpse into a pilot project in which the client pushes for decisions and even the ironworkers work solely with the digital model.
At first glance, the building that is currently going up in Esslingen seems quite standard: a three-storey extension for an office complex that was constructed in 1996. And yet it is placing greater demands on the persons involved than most major projects: “We want to use this project to take full advantage of the opportunities that digitalisation offers us in terms of planning, construction and management,” says Dominik Courtin, CEO of Basler & Hofmann, describing the challenges. He himself is wearing several hats: he is both the client and, by using his own planning team, also his most important contractor. “We want to experience for ourselves what systematic digitalisation really means.” Basler & Hofmann has experience with this type of experimental concept: the company has always used its office location in Esslingen as a research and development laboratory for new technologies and approaches. For example, the building, which is currently being expanded, was the first Minergie office building in the canton of Zurich. But what does it mean to take full advantage of the opportunities presented by digitalisation?
“I want a digital twin that will work for me throughout the entire life cycle.”
The main challenge facing the builder is that all of the persons involved and all of the different disciplines need to plan the construction project simultaneously with a single BIM model, which means using a single database. In this way, the project, which is called “Office Building Extension A – eGHA”, goes one significant step further than the most current BIM projects, which use what is known as a “federated BIM” approach, in which each discipline generates its own BIM model. These models are then coordinated at regular intervals. When all planners are working simultaneously within the same database, this coordination takes place in real time, rather than on a weekly basis. “We asked ourselves: With this pilot project, do we want to optimise the coordination of the models, or do we really want to plan this project in an integral manner and create a fully digital twin?” explains Mathias Kuhn, Digital Planning Process Manager at Basler & Hofmann. For Dominik Courtin, the decision was clear: “For me, using BIM only makes sense if, as the client, I receive a database that I can continue to use even after the construction phase is complete. I want a digital twin that I can use to simulate future modifications and conversions as well as facility management. This is only possible with an integral model.”
The future requirements determine the level of detail used in the model.
This approach, which takes into account the entire life cycle of the building, also presents challenges for the client. “I need to decide early on which information I will want to use later,” says Dominik Courtin. With the digital twin, it is possible to run through different scenarios to determine the best way to adapt the building services in the case of a conversion, or to see what impact different acoustic measures would have. The future requirements determine the level of detail used in the model. For the eGHA project, these decisions were made during the “felt pen phase” – this is what the team called the conceptual phase, in which they were not yet working in the model itself, but literally rather with pens. After this phase was completed, the team needed to decide which data would be recorded in the model before the actual “model phase” could begin.
The building is completed digitally before they even break ground.
Making decisions at a much earlier stage than they would in a conventional planning process is probably the biggest change for the builders and planning team. They can no longer simply say “we will figure that out later”. The building is completed digitally, all the way down to the flooring, before they even break ground. “Our goal is to create an optimised building. This is only possible if we address all of the questions and interdependencies ahead of time in the model and not on the construction site, which is usually the case nowadays,” explains Mathias Kuhn. “That is why we also included the contractor in the planning process early on. We wanted to make sure that their suggestions are directly implemented in the model.” This is also an unusual approach, as Alessandro Walpen confirms. He is the BIM Manager at Marti AG, the construction company for the project. “For us, it was great to be involved in the project at such an early stage. Today, the contractor is usually presented with a fait accompli and is not asked to provide any input in terms of optimising the planning process. This project, however, involves real teamwork.” And it offers major advantages for the client: the model allows the building to be completed digitally in coordination with all stakeholders before construction even begins. “There is no longer any reason to stop construction or add something later on,” says Dominik Courtin.
As the client, you cannot just shelve a decision because it is difficult.
This does not mean that the path to get here was not rocky: it required all stakeholders to let go of tried and tested approaches. Changes that are common in traditional planning processes require a tremendous effort in the digital twin. “Taking a traditional approach while using this digital model turns out to be totally inefficient and expensive,” explains Mathias Kuhn. Making decisions early on is often challenging – not only for clients, but also for architects and planners because they need to complete the basis for the decisions in advance and allow the clients to make timely decisions. “You have to really push,” says Dominik Courtin. “My stance was: if the choice of washbasins used affects the connections, then I will make a decision on the washbasins now. As the client, you cannot just shelve a decision because it is difficult in the moment.”
“Our model is suited for use on site.”
Construction in Esslingen started in May 2018 and has been carried out with as much digitalisation as possible. Foreman Dominic Mozzetti’s most important tool is his tablet computer, which allows him to access the geo-referenced digital twin via the construction site network. You will not find any blueprints at the site. Working together closely, the planners and construction site team tested the combined use of the digital model, tablet and measuring devices in advance. “A number of us predicted that a building site without 2-D blueprints would never work. But we have proven that it does in fact work – even better than we thought,” says Alessandro Walpen. The digital tools allow for much simpler and faster measurements at the construction site in particular. The Basler & Hofmann planning team has created different views from the model for specific tasks – for example, the ironworker team can pull up the reinforcement layer by layer on their tablets. “I have never seen anything like this in a model before,” says Alessandro Walpen. Mathias Kuhn takes that as a compliment for the planning team: “Our model is suited for use on site.”
“Using BIM solely as an additional requirement does not add any value.”
This type of integral process is still uncharted territory. “We want to get the most out of this digitalised approach in order to learn as much as possible and push the boundaries of what is possible,” says Mathias Kuhn. This approach is not suited for every project or for every client. What he does recommend for every client, however, is to learn about digitalisation, define their own goals and try it out for themselves with a simple pilot project. “A conventional tender in which BIM is listed in the last sentence as an additional requirement does not add any value.” Dominik Courtin agrees: “Clients should be entitled to receive a digital twin that meets their requirements throughout the entire life cycle of the project.” That is where he sees the greatest potential for these kinds of projects, adding: “When it comes to this approach, the industry as a whole is still at square one.”
Client: Basler & Hofmann AG
Overall project management: Basler & Hofmann AG
Architecture: Stücheli Architekten AG
Building contractor: Marti AG
BIM coordination: Basler & Hofmann AG
Specialist planners (structural engineering, foundation engineering, building services, structural physics/acoustics, fire engineering, service piping): Basler & Hofmann AG
Data collection for modelling of the existing building (laser scanning, drone photogrammetry): Basler & Hofmann AG
Facade planning: feroplan engineering ag