From docks to bridges and tunnels, retaining walls and noise barriers to offshore wind energy installations. We develop economical construction approaches for individual building projects.
For the Offshore Windpark DAN TYSK in the North Sea, 70 km west of the island of Sylt, several services have been performed. Starting with the supervision of the offshore borings a predesign for a submergeable gravity foundation has been elaborated. In the course of the project supervision and surveillance of the Monopiles, the Transition Pieces and the Towers in Belgium, the Netherlands and Denmark have been carried out. In Kiel and Emden we were responsible for the supervision of the Accomodation Platform including the foundation (Jacket).
In order to extend the southern waterfront promenade in the district HafenCity and to gain land for the U4 stop at the Elbe Bridges, a 160 m long quay wall was constructed and backfilled. In order to ensure the careful installation of the quay wall in conjunction with the existing abutment foundations of the Elbe Bridges, the king piles of the combined sheet pile wall were set in bored holes and their foot was concreted in place. This was followed with the intermediate piles being pressed into the subsoil and drilled micro piles were installed as anchorage.
Rehabilitation of berth 1 to 7 at Shuwaikh Port, State of Kuwait, was required due to the very poor conditions of the 1,330 metres of quay wall. The new structure shall ensure the safe berthing of 70,000 ton vessels and handling of containers, general cargo, and RoRo traffic.
The existing Kattwyk bridge (built in 1974) is designed as a combined road and railway bridge and does not longer satisfy the increased demands on traffic in the port of Hamburg. Therefore, a new construction of a two-track mobile lift bridge is planned north of the old lift bridge. The bridge consists of 3 sections with 2 foreland bridges of around 80 m span and the lifting section with a span of 135 m, which can be raised to NN +53 m when ocean going vessels are passing through. The foundation are abutments designed as reinforced concrete structures with a pile foundation in the embankment area. The steel pylons for the lifting part are set up on rc-caissons (layout 29 m x 14 m) with a foundation depth of 30 m below water level. Between these caissons is a culvert with an inner diameter of 2.0 m and a length of 120 m for the installation of cables for power an data. Next to the bridge construction, the entire junction has to be rebuilt. For this, further bridge structures, the adaptation of flood protection, supporting walls as well as the new construction of a light house for ship navigation with a height of about 30 m are necessary.
Additional cost due the plots and their history as port and harbour area have been evaluated and calculated by SELLHORN for more than 15 years. Before awarding contracts to investors, SELLHORN acting on behalf of HafenCity Hamburg Gmbh, identified additional site-dependent construction cost presented by the investors and prepared alternative solutions. Main items of design works refer to deep construction pits affected by tide water levels, controlled flooding concepts, requirements of storm water protection and technical concepts for foundations, quaywalls and subway vibrations.
The existing bridge over the Rethe (built in 1934) was designed as a combined street and railway bridge. Due to the traffic growth since its erection, it no longer meets the current requirements. For this reason, a new movable bridge for road traffic and railway was built. The new bascule bridge has a span of about 100 m, while road and railway traffic are led over two separate deck slabs to a joint abutment. Alongside the bridge, new riverside walls had to be constructed to secure the embankment. The channel was dredged and the leading light line had to be adapted to the new situation, making the construction of two leading light towers necessary. South of the bascule bridge, a new road traffic bridge with a span of about 200m was built to cross the rails of the station “Hohe Schaar”.
The main focus in this project in the Baltic Sea was the supervision of the installation of 80 Monopile and Jacket foundations for the client. Sellhorn was not only observing the work offshore on the ships, but was also responsible for the coordination of the interests regarding safety and environment (Sigeko and HSE) in the base harbour. In addition offshore observing/supervison tasks like inner array cable laying, installation of the turbines and transport/erection of the Offshore Substation were carried out. Beneath the overall quality requirements we were asked to take over the client representative function for this project and handled this successfully until commissioning.
The existing quay wall Hübenerkai was strengthened for the development of the HafenCity develpment in Hamburg. Since a refurbishment of the old quay wall was no longer possible, a new back-anchored sheet pile wall with steel concrete slab and masonry was built in front of the existing quay wall and the gap was filled. The construction is anchored by GEWI-piles from the water side. All works have been carried out due to tidal restrictions.
The existing quay wall at the Ericusspitze was strengthened for the development of the HafenCity district. In order to preserve the historic appearance of very prominent position in HafenCity, the old quay wall of 1890 was stabilized with a grouted anchor of GEWI-piles as well as a new reinforced concrete waling. Extensive renovation work on the masonry, on the quay wall equipment and on the old timber pile foundation was also carried out.
The railway station Eidelstedt Zentrum is to be extended for the two-track expansion and the electrification of the AKN line between Hamburg-Eidelstedt and Kaltenkirchen. To this end, existing walls of the trough building have to be rebuilt and replaced by new reinforced concrete walls in a modified position and arrangement. The existing grouted anchor must be adjusted. Further conversion work is to be carried out on the train platform as well as on the stairs.
The Offshore-Windpark consist of 80 Siemens turbines from 3,6 MW class and has an overall power of 302 MW. The construction of the windpark starts in 2014 and has gone to the grid in November 2015. Sellhorn supported Amrumbank West GmbH in planning the time scheduling to assure the overall timeframe of the project. One important part of this planning was the assessment of risks due to weather events offshore. Document control and scour protection for the monopiles are additional elements which have been supported by Sellhorn.
Within parallel railway lines of the HOCHBAHN and Deutsche Bahn (DB) bridge structures, which were in a worse condition, have been renovated. During regular bridge inspections it was stated that the structural condition of the bridges needs repairs, renovations and replacement. The renewal of 3 subway bridges in steel construction were designed as trough bridges. The abutments and foundations were repaired from the basis. The challenge from an authorization perspective was the creation of a submission for the application for planning approval (renunciation of Planfeststellung).
For the two-track expansion and the electrification of the AKN line between Hamburg-Eidelstedt and Kaltenkirchen, the single-track bridge is to be replaced by a double-track bridge. The bridge span was increased to approx. 10 m for an improved near-natural design of the river basins. The superstructure of the bridge is designed as I-shaped steel profiles embedded in reinforced concrete to minimize the height. The foundations are based on sheet pile wall abutments, which are designed rearward as cofferdam with horizontal anchors. The construction project takes place in a FHH-area (special european environmentally protected areas), which means that the impact of the construction measures have to be minimized.
For the two-track expansion as well as for the electrification of the AKN line between Hamburg-Eidelstedt and Kaltenkirchen, the single-track threading in and threading out into the train station Eidelstedt has to be supplemented by a second track. For this purpose, a total of approx. 300 m length of new support structures are necessary for terrain differences of up to a height of 8 m. The supporting walls are partly designed as trough constructions and as a bored pile wall with horizontal anchoring, for smaller terrain differences as angled supporting wall. The existing pedestrian crossing Weidplan is extended by a reinforced concrete frame.