Building a new cruise quay in Hernesaari next to Helsinki’s West Harbour
March 20, 2018 13:56 CET 6 min read
New quay is being constructed at the southern tip of Hernesaari next to Helsinki’s West Harbour. The dock will replace the Melkki dock in the Jätkäsaari district of Helsinki, where the dock area will be used for residential construction. The construction of the new Hernesaari cruise dock began in spring 2017. It will be completed before the 2019 cruise season begins. The new Hernesaari dock has been designed to accommodate ships up to 360 metres long. The dock will be implemented by the Port of Helsinki in cooperation with the City of Helsinki.
New quay is being constructed at the southern tip of Hernesaari next to Helsinki’s West Harbour.
The dredging and filling work related to the preliminary construction phase began in summer 2016. Contaminated soil was dredged from the area for the new quay, along with soft clay. The area was filled with approximately 302,000 m3 of rock, and the filling reached 2 meters above sea level.
In the EU-wide competitive tendering process, Terramare Oy, was selected as the contractor. Terramare also participated in the preliminary construction. The company is specialising in maritime construction. Starting in May 2017, concrete elements approximately 13 metres high were cast on the quay area. During August and September, a large floating crane lifted the elements to their final places on the platform evened out at the bottom of the sea. 313 metres of elements have been installed on the long side of the quay, and a junction structure of 20 metres into the end near the old Hernesaari quay.
Due to the challenging ground conditions, part of the quay structure was executed as RD pile wall. RD pile wall offered better technical solution compared to the original Combi wall design. A total of fourteen RD600/12.5 piles with RM/RF-interlocks, of which the longest was 18 metres, were installed in the connecting structure.
Due to the challenging ground conditions, part of the quay structure was executed as RD pile wall.
SSAB delivered the piles to Terramare Oy and the installation was done by Styrud Boreal during September and October 2017. RD piles were produced in steel grade S440J2H. “RD pile wall solution was selected not only due to the challenging conditions but also to eliminate the need for erosion tile and to lengthen the service life compared to the original design. The service life was stretched to at least 50 years”, says Jani Vyyryläinen, Construction Manager, Terramare Oy.
Installation of the piles was done by Styrud Boreal.
After the drilling, the piles were shortened at their upper ends by 2-3 metres. The connecting structure is anchored by three Gewi bars into a storm bollard foundation constructed in conjunction with it. Once the elements were installed at the bottom of the sea, their background was filled with the blasted rock brought to the area earlier and the rest from different sites. During 2018 capping beam and rest of the civil structures will be finalized and new quay will be handed over to client the coming Autumn.