Partial Prestressed Concrete Slabs as an Alternative for Vehicle Decks of Steel Truss Bridges

Abstract

Steel truss bridges with continuous reinforced concrete slab as vehicle decks are often found in Indonesia. The use of continuous reinforced concrete slab along the steel truss bridges has still have some problems in the field such as the occurrence of cracks. Cracks that occur on the concrete slab are required to be repaired, which is mostly done by grouting method. However, the method are still unsuccessful in addition to costly expensive.Study on partial prestressed concrete slab as vehicle decks of steel truss bridge was done. The system used was a partial prestressed concrete segmental slab in one direction which was set transversely the bridge. Two concrete slab specimens were cast which had a length of 7000mm, a width of 1000mm and a height of 250mm, respectively. Symmetrical reinforcement consists of four non-prestressed steel bars and three strands, placed on the top and bottom sides of the slab. The steel bars have a diameter of 18mm and the strands have a diameter of 0.5 inches. Plain steel bars with a diameter of 10mm were used as stirrups, spacing at 200mm. The slabs were then tested in the laboratory with a gradual loading increament. At every stage of loading, crack width and strain of steel reinforcement were measured.The test results showed that at the service load condition according to the BMS standard, no cracks was occurred on the concrete slab and the non-prestressed reinforcing steels were still under compression. At maximum load condition, cracks occurred evenly spaced at 85,5mm to 112,5mm and a maximum crack width was 3.2mm. Based on the test results, it can be concluded that such partial prestressed concrete segmental slab was very good to be used as an alternative for the vehicle decks of steel truss bridges.