Tendencies in Multi-Span Large Deck Construction with Cast in Situ Process
1Av D. Afonso Henriques 1462 2&ordm;
In the past decades, a “critical range of spans” – 70m to 100m - for multi-span viaducts with concrete decks has been identified. The most common construction methods adopted for that type of viaduct are 1) cast in situ free cantilever; 2) precast segmental free cantilever and 3) precast full segment. The first is a low productivity method, with medium material consumption and with low equipment investment. The second is a medium productivity method, with high material consumption and with medium equipment investment. The third is a high productivity method, with medium-high material consumption and with very high investment in equipment and site facilities. With recent technological developments, another possible 4th alternative may be considered and studied for certain bridge types within the span range of 70m to 100m: in situ, span by span construction. In this presentation its features and its limitations are discussed considering the involved technological challenges.