The Polak Building on campus Woudestein was closed two weeks ago when cracks were found in the floor. The cracks are notable because the building was also closed in 2017 because of an unsafe floor structure. Nijsse believes it is quite likely that the new cracks were caused by the construction errors and the vibrations caused by the construction work taking place next to the Polak Building, where a similar building accommodating lecture rooms is being erected. Simon Wijte (Professor of Sustainment of Concrete Structures at Eindhoven University of Technology) and the Association of Dutch Construction Companies believe it is too soon to draw conclusions and wish to wait and see the results of the formal investigation before issuing any statements on the matter.
Car park collapsed
The Polak Building was put into operation in 2015 and was temporarily closed two years later as a study showed that the building had the same type of flooring as the infamous multi-storey car park at Eindhoven Airport, which collapsed during the building stages. Royal Haskoning DHV, a consultant to Erasmus University, drew up a plan of reinforcement measures. In March 2018 the building re-opened its doors, and students were once again allowed to use their favourite study spots.
When cracks were discovered in the ceilings on several floors two weeks ago, the building was vacated again at once. Royal Haskoning DHV was hired once more, this time to investigate the cause of the cracks. When we asked the company how the investigation was progressing, we were referred to the university, which in turn stated that it was not yet able to provide any information.
Unproven theory
Asked to issue his professional opinion on the cracks in the ceilings of the Polak Building, TU Delft professor Rob Nijsse said that there might be a correlation between the shortcomings in the floor structure and the cracks that have recently been discovered. Nijsse also believes that the fact that a new building is being erected next to the Polak Building may play a role. “My theory, which has not yet been proven, is that after the fortification measures of 2018, the Polak Building was only just safe enough to be able to be used. Vibrations caused by the pile-driving going on next door may have caused the cracks in the floors, and now the safety of the building can no longer be guaranteed.” By now the piles forming the foundation of the second multi-functional teaching centre have all been driven into the ground and construction work is in full swing.
TU Eindhoven’s Simon Wijte is a little more hesitant to issue any statements. He feels it is now up to Royal Haskoning DHV to investigate what exactly is going on in the building and what caused it. “The previous fortification measures were in accordance with the insights available at the time. To the best of my knowledge, they were implemented correctly, thus allowing the building to be re-opened.” Moreover, Wijte is not aware of any other buildings with wide slab flooring where structural problems arose after fortification measures had been implemented. But as far as the Polak Building is concerned, Wijte is not willing to say anything at this stage about a possible correlation between the cracks found and the type of floor structure used. “As long as you don’t know what kind of cracks they are, you can’t draw any connections. We should be very careful to do so.”
No turmoil in the construction world
Bob Gieskens, the President of the Association of Dutch Construction Companies, agrees with Wijte’s statement. He says there are many possible reasons why the cracks might have developed. “Cracks must be considered warning signals”, he says. “So the next thing to do is to determine whether you are dealing with a severe construction issue or maybe just a superficial shrinkage crack.”
The Association is closely following the Polak Building case, but Gieskens does not believe that the construction world is in a state of turmoil because of the building’s second closure. “There have been no signs that buildings can suffer problems from wide slab flooring structures following fortification measures.” Examinations of that type of flooring and of the buildings that have been erected using it are still ongoing all over the Netherlands. Gieskens says that a lot of research has been conducted in the last three years on the production methods and designs of such buildings, to prevent new designs from being saddled with the same issues.
