Overview
Expansion joints and bearings are weak points of bridges and their use leads to the need for maintenance work, even if they have been correctly designed and detailed. For these reasons, these elements should be avoided if possible (integral construction). Apart from fully integral bridges without expansion joints nor bearings, it is also possible to avoid only the expansion joints (semi-integral construction).
With integral and semi-integral bridges, (cyclic) relative movements occur between the bridge ends and the backfill, causing settlements behind the abutments and cracks in the pavement. These effects may negatively affect serviceability.
Today, there is only very limited information available regarding the long term experiences with integral and semi-integral bridges, particularly regarding the required maintenance works (grouting of cracks in the pavement, pavement shifting), depending on the detailing of the bridge ends. Therefore, it is hardly possible to reliably judge the problem of serviceability near the bridge ends. However, such information is crucial In order to fully profit from the high potential of integral and semi-integral bridges.
The proposed research project shall thus investigate the long-term experiences with existing integral and semi-integral bridges in Switzerland.
Today, there is only very limited information available regarding the long term experiences with integral and semi-integral bridges, particularly with respect to the required (pavement) maintenance. However, such information is crucial in order to fully profit from the high potential of (semi-)integral bridges. The research project shall thus investigate the long-term experiences with existing (semi-)integral bridges.
Based on the results, the limit of applicability for (semi-)integral bridges according to the guideline can be verified and adapted if appropriate.
Furthermore, the proposed project will be helpful in order to decide whether on-site measurements of an existing integral bridge would be useful and – if yes - contribute to the selection of an appropriate bridge. Such measurements would be part of an independent project.
- Evaluation of suitable properties, with the support of civil engineering structures database of Astra and survey of specialists engineering structures of the Astra and the bridge engineers of Cantonal Civil Engineering Offices
- Procurement and study of the structure files (concept, inspection results and carried out maintenance work)
- Tour of the buildings, receiving the current state (photographic documentation, measurement of crack widths in building and lining)
- Survey of builders (particularly with respect to previously successful maintenance work)
- Compilation of the results (tables and charts)