“Domovinski most”, the Bridge in Zagreb – Specifics of Main Span Construction

The Homeland Bridge, project currently realized in Zagreb, is the new great city bridge over the Sava River. It will be 840 m in length, composed of 13 spans. The main span on the river itself is the extradosed prestressed concrete structure, with low pylons. This paper presents construction of the bridge, specially the main span system and concrete technology for casting of middle span segments by concreting whole segment without break. Quality control testing of fresh concrete on the site and hardened concrete, especially strength development in the early age of concrete, are also described in the paper. The use of maturity method is described in more detail. The maturity method is a technique for predicting concrete strength based on the temperature history of concrete. The extend of the cement hydration and thus of strength development of concrete depends on how long and at what temperature the concrete was cured, especially at early ages that are relevant for early prestressing. Therefore measurements of concrete temperatures were made on site, both of the structure and of the field cured specimens.