Schietbaan Marineterrein

This walkway, built from reclaimed timber and steel, is located above what used to be a shooting range. It creates a social meeting point in an area of the city that is in the process of being converted from a military compound to a mixed use residential and commercial area with more than 800 homes and a city park. Summum Engineering was responsible for the structural design and detail engineering of the timber structure.

The Schietbaan Marineterrein, is in a place in motion. It is a gritty corner of the Marineterrein, in the heart of Amsterdam, that is being revived. This central urban area of almost 13 acres is organically transforming.  It already houses innovative entrepreneurs and educational institutions and functions as an urban lab, experimenting with urban interventions for a sustainable and equitable future.

The area features great sunset views over the water within the back the old town of Amsterdam. But has been a shady and uneasy part of the Marineterrein for some time. Central to this corner is an old shooting range, a windowless bunker that was once the place where the navy held shooting exercises. The structure has undergone several attempts at repurposing but has primarily become the canvas for an ongoing graffiti battle.

Design

The walkway was developed by Walden Studio and New Grounds, based on a phased design strategy for this area, in which local businesses, passersby and nearby residents were asked what functions they saw fit for this location.

The result enables the most desired functions that were extracted from the interviews. The broad staircase doubles as a grandstand for outdoor lectures in the public square that is created in front of it. The walkway provides wonderful views over the water, and access to the future herb garden on the roof. It also provides shelter and shade to the outdoor working spaces and terrace, so one can relax and enjoy the food bought at the local bakery the bunker now houses.

The bunker, left over from the dismantled military base, is altered with the addition of a sculptural structure that emphasizes movement. The zigzag shape of the bridge and sculptural railings create a playful and dynamic route – a sense of accelerating motion over the bridge. Along this route, the views over the area and through the trees are surprising, despite its modest length.

Structure

Although half of the walkway spans across the military bunker, it does not rest on it. This is because the dimensions, materials and characteristics of military structures are classified and it was not possible to obtain data on their loadbearing capacity. Therefore, the footbridge is supported on steel frames. On top of these steel frames is the walkway, made of timber elements that form a parametric truss bridge.

Circularity

To realize the design, in line with ambition of Marineterrein, this walkway also made as a radical exercise in circular building. The vast majority of materials have had a previous life in another structure. Three of the most frequently used construction materials; steel, wood and concrete were all repurposed with as few modifications as possible without compromising the quality, creating a rugged but thoughtful aesthetic.

The dynamic wooden trusses of the bridge are made entirely from timber from a harbor retaining wall (a wooden sheet pile wall) that was dismantled. These are a common sight both in the city and the Dutch countryside. The assumption was that the wood has become stronger through years of standing in water and the preservatives have leached out. After various tests on the quality of the wood, permission was obtained to build with this wood. As a result, even after sawing, the wood looks beautiful and tells the story of years of exposure to water.

To support the bridge, a steel supporting structure was designed and made from the steel of a demolished cowshed. The steel was ‘harvested’, then cut to size, sandblasted and repainted. The concrete for the foundation of this construction is made with 80% circular cement and mortar. What is also special about this foundation is that it is above ground so as not to block or break the roots of the surrounding maples and ash trees. At the same time, these blocks serve as benches for the terrace and the outdoor workplaces under the walking path.

Engineering

There are several challenges involved in calculating a structure made from reclaimed materials. For a regular building element, made of new, virgin material there are two main parameters that an engineer can change: the material of which the structure is made of, with its strength or class; and the dimension of its cross section.

For this project the available material was already a given, so we needed to engineer the structure with a fixed size of beams and fixed material resistance. Furthermore, because the material is coming from the dismantling of another structure, little to no data on its strength or quality is available, so conservative values had to be used.

By carefully designing trusses with strategically placed steel reinforcements, it was nonetheless possible to engineer and detail the walkway. The enthusiastic team of Oostveen Tuinen & Houwer Bouwt was then able to fabricate and construct it over the course of a few months.

Outlook

This part of the Marineterrein is now increasingly under development. The transformation creates the opportunity to use the space in many more different ways. Now located within the front section of the bunker, the Kometen Brood Loket bakery offers freshly baked goods and coffee. The bakery, along with the walkway, draws an increasing number of visitors to the site, filling the terrace under the bridge on sunny days. This transformation breathes new life into what once an abandoned corner of Amsterdam.

Client
Bureau Marineterrein Amsterdam

Design
Laurens van der Wal, Sebastiaan van Kints | Walden Studio
Boj van de Berg | New Grounds

Engineering
Anand Shah, Aitor Vadillo Barcelona, Diederik Veenendaal | Summum Engineering (timber engineering)
Denis de Vos | B&V Raadgevend Ingenieurs (concrete and steel engineering)

Contractor
Oostveen Tuinen & Houwer Bouwt (reclaimed wood)
Vlaar Groep (reclaimed steel and concrete)

Suppliers
Leemburg Waterbouw (reclaimed timber)
ZTE Metaalbedrijf (recycled steel)

Landscaping
Hanneke Marseille | Tuinen van Marseille