Formwork technology provides solution for complex basement construction under new UvA university library

The University of Amsterdam (UvA) is reducing housing for education and research from some 85 buildings to four campuses in the city. One of these, the University Quarter, will also house the University Library. To this end, the former Binnengasthuis hospital will be renovated and expanded with new construction. To encourage the use of bicycles as much as possible, a large underground bicycle storage facility for 950 bicycles will be built. NOE Formwork Engineering developed a special formwork solution for the interior and exterior walls of this basement.

The Binnengasthuisterrein in the University Quarter has a long history of diverse functions. Its history dates back to the Middle Ages, when the Old and New Nunnery were located here. The area housed a convent, hospital, museum, residential area and university. The University of Amsterdam started here, as Athenaeum Illustre, in 1632. The monumental Second Surgical Clinic and the Sisterhouse of the former Binnengasthuis Hospital are now being renovated and complemented by new construction, creating one building for the library. Eye-catching elements in the design include a spectacular glass roof and a new construction wing. Structural precision is required in the construction of a basement with sunken atrium under the existing building.

Remarkable undercroft

Basement work in the historic center of Amsterdam is being performed by Van Hattum en Blankevoort & Volker Staal en Funderingen. Because of the many modifications and expansions that have been made to the building over the years, the shape of the basement is complicated. In order to sub-basement the building, piles and temporary steel beams were first installed under the monument, which took the load from the entire building. Next, the foundation beams were demolished and a new floor was installed for the first floor. With the load-bearing structure under the future library, the basement could be excavated to a maximum depth of 5 meters and a concrete basement floor poured. Between the two floors, all interior and exterior walls then had to be installed. In doing so, the walls follow the shape and layout of the current building. 

Handy and loadable formwork system

For the formwork technology for these walls, Van Hattum en Blankevoort sought a solution that was not only handy and easy to handle, but could also support a concrete pressure of up to 65 kN/m2. NOE Formwork Engineering offered a solution that met both conditions with the NOEalu L formwork system. This lightweight aluminum wall formwork can be easily processed while still withstanding high concrete pressures. The development of NOEalu L was based on a system that can be transported by hand, but at the same time can meet the required concrete pour pressures of construction. 

In-work pumping of concrete

The challenge here was the pouring of the concrete. Whereas concrete is normally poured on site through the top of the open formwork, this was not possible with a formwork locked at the top and bottom. Thus, pumping self-compacting concrete was chosen. NOE Formwork Engineering provided a solution for this by providing the wall formwork with filling points positioned at strategic points at 0.5, 1.5, 2.5 and 3.5 meters. The filling points, to which the concrete pump is connected, were fitted with a valve so that the concrete could be applied in layers of 1 meter. The composition of the self-compacting concrete was thereby chosen so that the concrete could flow to both sides over a distance of 10 meters. At the ends of the formwork panels, vent holes were provided where the air was fed out through the rising concrete.

Now that the new foundation and basement walls are nearly complete, the temporary steel beams can be removed from the building one by one. In addition to bicycle parking, the many new square meters will also provide space for technical facilities, book lending (pick up & return) and a multipurpose sunken atrium. The university library is expected to open in 2023.