Dynamic effect of transition zone and rail corrugation on the bridge response
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Transition zone is the area where the stiffness of the track changes abruptly. This condition usually occurs close to the abutments of the bridge, near the tunnel entrance or intersections. This change of stiffness can effect negatively as dynamical point of view. Therefore, engineers try to solve this problem by changing the stiffness smoothly.
In this thesis, the track and bridge have been modelled with and without consideration of transition structure to study the dynamic effect on the bridge response at different speeds. Span lengths of the bridges vary from 5 meters to 25 meters. To model this 2D structure, ABAQUS and MATLAB software have been used. The transition structure (approach track) lengths are changed as 0.25L, 0.5L, 0.75L, 1L, where L is the bridge span length. The results show that there are almost no differences in maximum vertical acceleration and displacement on the bridge structure while using different length of approach track in the model.
The effect of transition length has been studied on the maximum acceleration and displacement of the bridges. In the case where the transition structure is considered, track stiffness variations will be distributed along the transition zone and this moderates the shock. This distribution is smoother in longer transition structures.
Moreover, for each span length, two maximum peak accelerations were considered and the corresponding speeds extracted. The first speed is the lower speed and the second one is the higher speed. By applying rail irregularity where the maximum acceleration occurs on the bridge, the effect of corrugation was investigated. As a result, deeper and periodic irregularity creates higher acceleration for the first peak speed, which is the lower speed. On the other hand, since the second peak (acceleration) speed is high, more period irregularity for the second peak speed creates lower acceleration.
Place, publisher, year, edition, pages
Trita-BKN-Examensarbete, ISSN 1103-4297 ; 340
Transition zone, Approach track, Railway Bridge, Track, Dynamics, Acceleration
IdentifiersURN: urn:nbn:se:kth:diva-99384ISRN: KTH/BKN/EX-340-SEOAI: oai:DiVA.org:kth-99384DiVA: diva2:542062
Subject / course
Structural Design and Bridges
Master of Science in Engineering - Urban Management