Unique renovation carpark Weena in Rotterdam
The Weena carpark, build in 1968, has a capacity of 541 parking lots and be made up of a basement floor and 4 storey floors above a substructure with offices and business premises. After many reports of leaks and damage in the floors, it turned out that the Weena carpark needed a full renovation.
The preliminary investigation prior to the tender had resulted in the floors showing many concrete damages. These damages were mainly at the level of cracks that had occurred in the relatively thin floors (160 mm thick). Right next to the beams of the monolithic concrete skeleton. Due to the requirement to maintain parking capacity as much as possible and to optimize the speed of work, a start was made on the 1st and 4th floors at the same time. Most of the work was planned on the 1st floor since the original cast asphalt finish was still there. After completion of the 4th floor, the 2nd and 3rd floor were tackled so that 2 floors were always fully available for parking.
Well corrosion by thawing salts
Based on data from the preliminary investigation, SealteQ had already recommended the use of galvanic cathodic protection to prevent continuous corrosion of the reinforcement. After all, with traditional concrete repair, corrosion by chlorides is not stopped. The penetrated thawing salts (chlorides of broken-in brine) cause well corrosion in the reinforcement, which can present a structural hazard. After remediating the damage, the extent of the damage on each floor was more than doubled. On the 2nd and 4th floor where the damage was still fairly concentrated at the level of the cracks, it was possible to repair locally. The corrosion could still be checked with galvanic anodes, which were welded onto the released reinforcement. On the 1st floor, the damage was so extensive that applying local anodes could no longer provide a solution and additional measures became necessary.
After the cast asphalt had been removed on the 1st floor, the seriousness of the structural damage only became apparent. Based on the damage that was then visible, this was already four times the set assumptions. The main reinforcement had virtually disappeared due to corrosion at many locations. To get an idea of the invisible damage, SealteQ has set up an extensive investigation. All corrosion activity of the reinforcement is measured by, among other things, carrying out potential measurements. The corrosion activity is precisely located based on the potential maps.
Based on the information obtained from this study, SealteQ has designed a cathodic protection system with imposed current based on titanium strip anodes. Due to the large size of the surface to be protected, galvanic protection was no longer an efficient solution here. Based on the data on the potential maps, a very efficient protection has been achieved at the locations where there was active reinforcement corrosion in the floor.
First, the damage was repaired with newly welded reinforcing bars. Titanium strips were then applied to the surface of the floor. The floor of the 1st floor is divided into three zones. This was necessary for the targeted management and distribution of the cathodic protection system. By installing so-called titanium current distributors with anode contacts and making sufficient cathode connections to the steel to be protected and made continuous, a very efficient and effective protection of the reinforcing steel has been achieved. The cathodic protection system is controlled by remote and will be checked 4 times a year. If necessary, the system can be adjusted to effectively protect the reinforcement steel against corrosion.
After the application of the system, the entire floor was covered with a high-quality cement-bonded and highly conductive leveling mortar in a thickness of at least 15 mm. This layer is not only important for a flat surface. Also, for sufficient conduction of the protective current from the cathodic protection system to the reinforcement.
After dust-free blasting, a heavy 4-layererd crack-bridging screed floor system was applied to the sufficiently cured cement-bonded substrate. Standardized in accordance with DIN Os-11a. Through the combination of an elastic membrane layer and a heavy-duty pour-in layer, a durable floor system has been installed which, in addition to a high mechanical durability, also prevents new cracks from re-entering the thawing salts.
A wear-resistant top layer was then applied to the heavy system layers. Subsequently, all parking bays, symbols and lines have been placed on the floor in the same polymer system.
This high-quality polymer parking deck system has been installed on the various floors in the corporate identity of operator Q-Park. The system will contribute to years of trouble-free use of this characteristic garage in the center of Rotterdam. A project where our specialists have combined a great deal of knowledge and specialisms to complete the project to the full satisfaction of the clients.