The City of Amsterdam has a serious space shortage and is looking for business locations that can be redeveloped into housing. One such is the location on Spaklerweg in Amsterdam Amstel, where network company Alliander has been housed for more than 100 years. After a joint search, the city and network operator have found a suitable plot for a new building in the Sloterdijk 3 port area.

Liander Westpoort is the new sustainable office of network company Alliander, located on the Noordzeeweg in Westpoort. Designed by De Zwarte Hond, the regional office, with wooden construction, consists of offices, workshops, warehouses, test rooms, training, and parking facilities (total 21,000 m²), for 700 employees. The starting point for the integral design was the idea of making a better building for the same budget. This objective fostered a rousing dynamic within the cooperation on the design, as project partners (Alliander, De Zwarte Hond, IMd Raadgevende Ingenieurs, DGMR, Copper8 and Coare) jumped over their own shadows and went the extra mile to help each other and jointly devise smart solutions.

A rhythmic alternation of buildings and interspaces are positioned on the plot like a barcode, with the office building at the head, visible from the A5 highway, as a height accent. The equal attention which was paid to all parts of the programme is striking throughout. Work buildings and storage areas have been designed with the same care as the office building and forged together into a robust whole. It evokes memories of the heyday of industrial architecture. The central wooden stairs in the large atrium of the office building create an environment that encourages encounters and interaction. A unique 'roving staircase' connects each floor at a different location and provides an exciting route through the office.

Variant studies for the structural design clarified how we, as a team, could arrive at the best building. For instance, we investigated the impact of a steel, concrete, and timber frame construction on the element’s environment, building costs, flexibility and adaptability, circularity and demountability. Based on these different criteria, three options emerged: timber hollow-core slabs, an open ribbed floor and CLT (Cross Laminated Timber). For the structural design, we eventually chose a laminated timber skeleton of columns and beams, and timber hollow-core slabs. To make execution less dependent on the timely supply of specific materials, the concrete precast stability core and the building's timber structure were constructed independently.

The wooden beams continue over the columns, creating long (trade) lengths that are fastened as limited as possible, to minimise damage to the beam. This is beneficial, as any bolt, slot or indentation would be a deterioration of the beam and therefore a limitation in future reuse. Applying these long lengths reduced the required size of the beams. To allow the beams to span over the columns, IMd Consulting Engineers designed a unique demountable steel node that ensures the beams are not loaded in the weakest direction, perpendicular to the fibre. The high column forces resulting from the considerable height of the building can therefore be easily carried through. The combination of the long beam lengths and the demountable nodes makes it easier to reuse the beams and columns as complete elements. In addition, no anchors are glued into the timber, which enhances the possibility of disassembly and reuse.

From the start, we worked very closely with DGMR to ensure good coordination between construction and plant engineering and building physics. Partly with a view to flexibility, we chose to integrate the same, accessible installation in the construction almost everywhere. With the ambition to use wood as much as possible in the construction and to achieve an elegant integral design, the wooden floor slabs were slightly spaced apart on the initiative of IMd Raadgevende Ingenieurs. As a result, we created piping zones between the floor slabs, so that both the installations and floor slabs were also demountable and no openings for pipes were needed in the wooden beams underneath. In this way, the structural design was developed further and further, with the ambition to use building materials carefully and to create a future-proof building that would never have to be demolished.

Fire safety required only limited measures. For example, a sprinkler system was not necessary, partly because the escape route is secured in the concrete stairwell. Nor was a sprinkler system desirable due to the client's explicit wish to be able to easily redesign the building in the future. Timber props protect the steel fasteners in the joints from melting in case of fire. The girder-column connection detail designed by IMd Raadgevende Ingenieurs meets the fire resistance requirement of 90 minutes without fireproofing.