Projects
/
12/28/2023
Crown Bridges in Helsinki
A complete waterproofing system for one of the most imposing infrastructure projects in the Finnish capital
The Crown Bridges project is a clear sign of the will of the city’s authorities to promote sustainable transport, by building new bridges, rebuilding two existing ones and creating footpaths and cycle lanes while expanding the tram network
In August 2016 the Helsinki city authorities decided to construct a tram link between Helsinki and the island of Laajasalo, which lies to the east of the Finnish capital. The link will be 10 km long and will include three bridges, called Merihaansilta, Finkensilta and Kruunuvuorisilta, that will be accessible to trams, bicycles and pedestrians only. The longest of the three bridges will be 1.2 km, beating the previous record for Finland’s longest bridge.
The project also includes rebuilding the Näkinsilta and Hakaniemensilta bridges, thereby leading to the completion of five infrastructure projects in the city.
Apart from reducing congestion on the eastern zones of the city’s metro network, the project will also provide fast and reliable transport to and from the Laajasalo area, which has a growing population and is forecast to double with the construction of a new residential district called Kruunuvuorenranta.
The project is a clear sign of the will of the city’s authorities to promote sustainable transport, including through the integration of different systems and networks, encouraged by the creation of footpaths and cycle lanes and expanding the tram network. All these initiatives are being carried out also to overcome the increase in population in the Finnish capital which, from 658,000 in 2020, is expected to reach 870,000 by 2060.
The project includes a 10 km long tram link, three new bridges and two renovated bridges
A hybrid membrane for the decks
Construction work on the Crown Bridges project got under way in October, 2016 and is scheduled to be completed in 2026. From the autumn of 2022 until the autumn of 2023, a complete system proposed by Mapei OY, the Finnish subsidiary of the Group, was chosen to waterproof half of the decks of the Näkinsilta, Hakaniemensilta and Merihaansilta bridges: PURTOP SYSTEM DECK, which was applied over a total surface area of 13,600 m2.
The first step for this system was to treat the substrates, once they had been cleaned and sanded, with MAPEPRIMER M two-component epoxy primer, distributed on the Finnish market by Mapei OY. This product is particularly suitable for both damp and dry concrete substrates to improve adhesion of layers to be applied afterwards and, in this particular case, the product was applied in two coats and broadcast with quartz sand.
Application by spray of PURTOP 400 M on several sections of the deck of the Hakaniemensilta Bridge.
The next layer consisted of PURTOP 400 M solvent-free, hybrid polyurea membrane, which was applied by spray at a thickness of 2.5 mm using a bi-mixer pump. Thanks to its high tear resistance, tensile strength and elasticity this product is particularly suitable for creating waterproofing membranes on bridge decks. In addition, PURTOP 400 M guarantees immediate waterproofing and rapid set to foot traffic, requires no extra strengthening and does not overload the load-bearing structure: characteristics which, along with its low emission of VOC and low impact on the environment, makes it particularly suitable for use on infrastructures in cities, such as the Crown Bridges in Helsinki.
PURTOP SYSTEM DECK waterproofing system was also applied on the decks of the Näkinsilta bridge.
For some of the bridges in the project, such as the Näkinsilta, Hakaniemensilta and Merihaansilta bridges, asphalt coating was installed in areas used as tram and bus stops. To improve adhesion of the layer of asphalt to the surfaces waterproofed with PURTOP 400 M, these surfaces were treated with PURTOP PRIMER NERO, a one-component, low-viscosity anchoring primer used to promote adhesion for surfaces waterproofed with PURTOP 400 M hybrid polyurea membrane or PURTOP 1000 pure polyurea membranes, before applying the keying coat for asphalt road surfaces. This waterproofing system met with the requirements of the owner, ensuring excellent performance. And so, it will be used again for other surfaces of the new sections of the bridges, currently under construction, which are part of the grandiose Crown Bridges project.
Product Lines
Projects
12/15/2023
Syariah Courts of Justice in Kuala Lumpur (Malaysia)
Interviews
12/28/2023
The advantages of using Mapei poyurea-based waterproofing systems
