NOVEL DEVELOPMENTS TO PRECAST BRIDGE GIRDER TECHNOLOGY BY THE BME-ZÁÉV RESEARCH COOPERATION

Abstract

The Competence Center on Safety Science and Technology joints significant research effort of the Budapest University of Technology and Economics (BME) and the potential industrial partners on several fields of industrial safety. On the building industry branch of this project novel bridge girder technologies have been developed by the cooperation of the Civil Engineering Faculty of BME and the ZÁÉV Construction Co Ltd. (ZÁÉV). These technologies aim to reduce the production time and cost, utilize the structural benefits of post-tensioning and ensure sufficient durability for products subjected to extreme chloride and freeze-thaw effects. The main outcome of the project is the full development of a brand-new, 0,9 m high bridge girder family made of self-compacting concrete. The use of self-compacting concrete is completely new in bridge girder technology in Hungary where high compressive strength both at young age and sufficient durability during 100 years of service life are the major demands to complete. For this purpose two mixes including limestone powder and CEM III type cement as additions were developed and tested in laboratory and factory conditions. The practical applicability of internal bonded and unbonded as well as external unbonded types of post-tensioning with various layouts were tested on two-span prototype systems. Following the international trends to extend service life or to further improve the durability of bridges subjected to extreme environmental conditions, possible solutions can be either to use embedded fibre reinforced polymer (FRP) bars instead of traditional steel ones as reinforcement in concrete or to structurally combine them with post-tensioning of full corrosion protection in hybrid-type bridge girders. The applicability of all these developments were demonstrated by failure load tests on full-scale prototype units of the girder family using an exclusive loading platform built on the storage area of the manufacturer. The developed bridge girder family already has CE marking.