Information exchange in existing buildings differs significantly from that in new-build projects. It is therefore essential that all partners in the construction chain work according to the same methodology. The ILS Existing Buildings Working Group is developing new guidelines for information exchange in BIM. These guidelines are now being shared with the market for validation and feedback.

Designing for an existing building requires consideration of heritage values, structural possibilities and constraints, and the technical condition of the property. Because a BIM model functions not only as a design tool but also as a communication tool, it must be practical for all parties involved: consultants, surveyors, and contractors alike. The new ILS for Existing Buildings helps optimize the digital approach to projects involving existing buildings.

Lijnbaan 101–111, originally designed by Krijgsman and Van Duin Architects and completed in 1967, has been renovated several times over the years. In 1998, D&T van Manen Architects carried out a renovation in which two large Octatube curtain-wall facades were added.

Boltt asked Octatube to investigate whether the single glazing in these facades could be replaced with more sustainable alternatives. For Octatube, which is increasingly involved in this kind of sustainability challenge, this formed a relevant part of the project. Octatube subsequently contributed to the engineering. The facade of the left-hand section, designed by Mei architects and planners, was completed in the summer of 2023.

Together with project manager Bouwplot, Boltt developed an action plan to improve the sustainability of the two buildings and merge them into a single retail environment. In a series of short, focused sprints, the existing condition, the documents for the environmental permit application and the construction drawings were worked out in parallel.

Using archival drawings, Boltt incorporated the existing condition into a BIM model, which also formed the basis for the environmental permit application. This integrated model also included Nike’s requirements. The partition walls between the two buildings were removed, a new customer staircase and elevator shaft were introduced, a new storage area was added, and the entrance was moved from Lijnbaan 111 to Lijnbaan 105.

Boltt also prepared the construction drawings for contractor J.P. van Eesteren. PelserHartman first produced a point cloud of the existing condition, which Boltt then processed and integrated into the BIM model together with the suppliers’ models. Boltt also coordinated the process as a whole.

Urban Climate Architects was first informed by Urban Interest and Boltt about the scope of the study. After working for several years as part of a design or construction team, it can be difficult to maintain a fully objective view of earlier design decisions. For that reason, Urban Climate Architects was also interested in the outcome of the study.

Boltt began by examining the corridor layout of the building. Could limited structural interventions bring daylight into the ends of the corridors? And could repositioning the corridors lead to a different type of residential layout? We also reviewed the location of the bicycle parking area and the layout of the entrance zone.

Boltt then reviewed six floor plans with which Urban Interest was not fully satisfied. Within the given external contours of the building and the fixed shaft positions, we proposed a number of alternative layouts. We also explored several less conventional solutions, including a studio with a box bed.

Together with SBB Ontwikkelen en Bouwen, a strategy was developed for the construction phase that responded to the tight schedule and the expectations of all parties involved. Before construction began, feedback was gathered from the contractor and co-makers on the architectural principles of the final design. These principles were then incorporated into the 2D detailing and construction sections, aligning the design dossier with the construction process to come.

The BIM strategy was subsequently coordinated in full. The digital information cards developed by SBB played a key role in this process. These cards specify both the architectural information to be included in each element and the geometric representation required for that element across the different phases. SBB coordinated this information with the co-makers, and it formed the basis for the construction process.

To ensure close coordination between all parties, Boltt developed digital mock-ups of various building components, with specific attention to model quality, architectural elements and BIM data. To support the construction process, the model was developed in line with the construction schedule. The longer the lead time for a component, the earlier it was incorporated into the BIM model. This approach was made possible through close consultation and collaboration with SBB.

During the later design phases, we worked closely with contractor J.P. van Eesteren to refine this approach. Our technical designers developed a practical construction method that helped maintain the pace of construction, enabling the client to begin leasing on schedule while preserving Studio Gang’s design intent.

In a building of this height, a substantial amount of technical infrastructure converges on the lower floors, precisely where a sense of openness is most desirable. For that reason, we devoted particular attention to the technical design of the MEP zones. By integrating them into designated areas, we were able to preserve the spatial quality of the double-height commercial spaces.

Because of the limited space on site and the short construction period of just 18 months for a gross floor area of 12,000 m², contractor Van Wijnen required an exceptionally detailed BIM model, fully aligned with the work of consultants and suppliers. Prefabrication and direct installation from the truck were necessary to shorten the construction period and reduce construction errors. The BIM model also had to be suitable for checking the production models of the specialist partners.

Within the BIM model, the various building components, including natural stone, window frames, structural elements and steelwork, were developed separately. We organized and coordinated clash detection sessions to align the work with the consultants and contractor. In effect, the entire building was first constructed virtually, with the assembly sequence and site logistics already considered. During the production and execution phases, Boltt also checked the production models.

We advised Adyen to have the connection designed by an artist and to invite several artists to submit proposals. Amsterdam-based street artist Frankey presented the most compelling design. The environmental permit drawings were created by Boltt, and we advised Frankey on the presentations to the SIRK and the materialization of the design. We handled the further technical development, including the technical engineering for contractor Van Wijnen.

The bridge's facade is made of Acrylic One, with the facade panels formed using composite materials in 3D-printed moulds. The walkable glass floor spans from building to building. The lamppost, the balustrades, and the bolts are also 3D-printed.

From the preliminary design onwards, the project was developed as part of a construction team together with contractor Heijmans Woningbouw. In addition to the design work and technical development of the scheme, Boltt played a coordinating role and facilitated the BIM process throughout. The construction team met weekly in Rotterdam, allowing decisions to be taken quickly and the process to move forward with both speed and care.

The detailing was developed in close collaboration with Heijmans Woningbouw and its subcontractors. Because these subcontractors also contributed to the process as part of the construction team, the model and detailing took shape at a relatively early stage. As a result, fewer changes were required later in the process. This led to a key question: could the prefabricated structural elements already be produced during the design phase? In other words, how could the process be organized as efficiently as possible t?

Drawing on our knowledge of local construction practices and our background as designers, we assisted Studio Libeskind with the technical development and construction of this monument. The monument’s eventual completion was preceded by a complex process that spanned five years.

Every change or addition, from extra names to lamps and fences, and every minor obstacle along the way was immediately incorporated into the model.

By providing 3D models and detailed drawings, we were able to illustrate the implications for all external consultants involved. Since the focus had to remain entirely on the monument, all necessary but distracting technical elements had to be subtly concealed. Throughout the process, we worked closely with Studio Libeskind to find the best solution in every instance.

We were in weekly contact with Studio Libeskind to ensure that we stayed as close as possible to the essence of the design. Boltt wanted to know exactly which design aspects were important so that proposed changes that did not meet these criteria could be rejected by the project team right away, allowing us to quickly seek a better solution. The time difference between New York and Amsterdam worked in our favour; issues raised in the afternoon often received a response the very next day, Dutch time.

The structural engineer’s archival drawings formed the starting point for the model, while contractor BAM was involved at an early stage in producing 3D as-built surveys and point clouds. This made it possible to verify whether the level data in the point clouds corresponded with the archival drawings. Cross-sections through the point clouds also revealed the extent of the building’s tilt and whether individual components were out of plumb.

To gain a more detailed understanding of the building’s condition, we used high-resolution drone photographs of the full exterior. By comparing these with historical images and archival drawings, we were able to distinguish between original and later elements. This made it possible, for example, to determine that part of the first floor could be demolished. The historical material also helped identify elements that were not shown in the drawings, as well as details that had been replaced over time. One example is the steel windows with opening sections, which were reintroduced in the new design.

BIM was actively used as a communication tool between the contractor, architect, structural engineer and subcontractors. Using the Archicad renovation filter, we were able to clearly distinguish in the 3D model between existing elements, demolition work and new interventions. The same applied to load-bearing and non-load-bearing components, material properties, interior and exterior elements, and NL/SfB codes. The steel supplier also used the model as the basis for sizing its components.