Highway bridge in Gdansk

Building use

Other

Country/Region

Poland

Overview

The composite solution is adopted to build two highway multi span viaducts near the city of Gdansk, to connect the city center and its port to Poland’s highway system. The WD7 is a single deck multi span viaducts 170 m in total length, while the WD8 is a two deck, multi span viaduct of 390m in length. Spans range between 25 and 40 meters on both structures. Each span is composed by 5 pre-fabricated composite beams with cast in situ concrete topping.

Basic information (construction date, number of stories, gross floor area, adopted design code, engineer(s), Contractor(s), etc.)

Construction date: 2011-2013
Number of stories: –
Gross floor area: 10,200m2 of deck
Adopted design code: –
Engineer(s): Pawel Klimaszewski, Europrojekt Gdansk
Contractor(s): Skanska Poland Sa

Issue and/or innovation

The use of prefabricated composite beam technologies for bridges is now quite widely diffused in Europe, representing a viable alternative to prefabricated pre-stressed concrete beams. The innovate aspect adopted here is the use of a hot-rolled high-strength (S460) steel profile instead of fabricated S355 steel plated girders.

Reason for composite solution

The bridges span over previously-existing infrastructures, including a railway. Construction speed and prefabrication was thus important to avoid interference with the traffic below.

Specific solution/technical details

The specific solution adopted consists of a total of 137 hot rolled C460 steel beams. The beams act compositely with a concrete slab (100-150 mm thick) made with C40/50 concrete. After fabrication, the steel hot-rolled profiles are cambered and finished by welding the shear studs and the endplates. Transported via train and truck to the installation site, the collaborative concrete slab was poured with C40/50 concrete before assembly in the final position. Once hardened the concrete, the beams were suspended with a crane and installed in their final position and simply supported between the piers, causing no disruption to the traffic underneath. The finishing slab made with C35/45 concrete was poured.

Impact or effectiveness

The traditional plated girders made with S355 steel allow for a geometric optimization of the steel beam, for instance by thickening the section where the bending moment reaches its maximum. Instead, the hot-rolled S460 beams used here have a constant geometry which simplifies significantly the fabrication phase and other on site operations. The use of prefabricated composite beams also allowed the erection of one span per week. The use of high-strength hot-rolled profiles allowed a saving of about 11% tonnage versus a conventional plated girder with S355 steel, and a similar saving on material costs. Similarly, as hot rolled profiles are usually more “compact” than welded girders per mass unit, a saving of 15-30% of surface is achieved, resulting in a reduction of about 3300square meters of surface to be protected against corrosion, providing both an upfront saving and a significant saving during the maintenance activities required throughout the life of the bridge.

References / Technical Papers Content

Riccardo Zanon (Technical Advisory Engineer), Wojciech Ochojski (Technical Advisory Engineer), Oliver Hechler (Technical Advisory Engineer), Paweł Klimaszewski (Bridge Struct. Eng.) & Wojciech Lorenc (Assoc. Prof) (2014) Road Bridges WD7-WD8 on Route Sucharskiego, Poland – Innovative Steel-Concrete Composite Deck Solutions, Structural Engineering International, 24:4, 551-556, DOI: 10.2749/101686614X13854694314801