Response of slender road bridges and footbridges under traffic loading
Dr Ana Ruiz-Teran, Imperial College London
Dr Peter J. Stafford, Imperial College London
Dr Alfredo Camara, Imperial College London
Dr Khan Nguyen, Technical University of Madrid
Current research student:
Caterina Ramos, Imperial College London (funded by the “La Caixa” Foundation research scholarships). PhD student, jointly supervised by Dr Ruiz-Teran and Dr Stafford
Background, context and methodology
Verification of the serviceability limit state of vibrations due to traffic live loads can be neglected in conventional types of concrete road bridges but becomes critical in the design of slender bridges , such as in under-deck cable-stayed bridges .
In slender road bridges, the conventional deflection-based approach to indirectly assess the serviceability limit state of vibrations is not valid. It can lead to either over- or under-design . The dynamic properties of the vehicles, the size of their wheels, and especially the pavement quality (Fig. 1) are very important when assessing the maximum accelerations registered in a slender bridge due to the crossing of heavy vehicles .
The response obtained using movable loads can be used for a preliminary design. Nevertheless, using movable vehicles, and therefore more sophisticated models accounting for vehicle-structure interaction, is essential when a more accurate response is required for detailed design (Fig. 2) .
Verification of the serviceability limit state of vibrations due to traffic live load is also essential in footbridges, and in particular in slender footbridges. Our current research is focussed in this area .
 Ruiz-Teran AM, Aparicio AC (2009). Verification criteria of the sls of vibrations for road bridges with slender prestressed concrete decks. In: International FIB Symposium, London (UK); 2009.
 Camara A, Nguyen K, Ruiz-Teran AM, Stafford PJ (2014). Serviceability limit state of vibrations in under-deck cable-stayed bridges accounting for vehicle-structure interaction. Engineering Structures, 61, 61-72
 Ramos C (2014). Structural behaviour and design criteria of cable-supported footbridges. Doctoral thesis - Late Stage Review (jointly supervised by Dr Ruiz-Teran and Dr Stafford). Imperial College London