Within the frames of road investments planned in Poland to the year 2020 the number of bridge-type works made with the use of the incremental launching method has substantially increased. ULMA has recently undertaken the design and delivery of a special formwork which allows applying the incremental launching technology to construct two bridges: MS-6 viaduct on the S5 road and the E-1 Bridge on the S19 road, located in Poland.
The method consists in prefabrication of subsequent stretches of the bridge deck in a fixed prefabrication area and next, after prestressing them with already made segments, sliding them forward on prepared piers with the use of hydraulic devices. This method is particularly recommended in places where ground conditions prevent the use of conventional shoring system or when their use becomes uneconomical. Another important reason may be erecting bridge works of substantial length, characterised by fixed size cross-section as well as structures that are straight or have a spatial curve of constant radius.
E-1 bridge on S19
On the route of the S19 between the Świlcza junction (DK4) and Rzeszów Południe junction (Kielanówka) – a 476 m long E-1 Bridge is constructed using the incremental launching method. This structure with the straight-shape layout in a horizontal projection has a longitudinal gradient of 0.8%. The superstructure of the viaduct was designed as over 11 m wide and 3.5 m tall box-sections. The construction was divided into 17 stages of various lengths. One stage will be about 14 m long, three stages 24 m each and the remaining ones 30 m each. In case of this structure the system of hydraulic cylinders was used, which pull the superstructure on the constructed piers in 30-centimeter strokes.
ULMA was entrusted with designing and providing the formwork technology for the construction of foundations, abutments, prefabrication position and piers as well as scaffoldings to operate slide bearings.
The formwork design assumed preparation of the 30 m long launching position. The formwork solution was designed based on the universal MK System: ENKOFORM VMK and ENKOFORM HMK. MK System is a product with a wide array of applications and allows executing extremely varied configurations: from heavy load structures for civil engineering to lighter loads for buildings, always using the same basic components. The formwork technology with the use of the hydraulic system currently offered by ULMA enables stripping and re-closing of formwork during one duty cycle for the entire stretch, including the formwork of the bottom slab, external formwork and of cantilevers.