On the use of a simple tuned mass damper model for reducing the excessive vibration of tsunami evacuation suspension footbridge

Civil Engineering Department, Andalas University, Limau Manis, Padang, 25163, INDONESIA

^* Corresponding author: febrin@eng.unand.ac.id

Abstract

The suspension footbridges are commonly constructed in the rural area. The constructions method is relatively simple compared to other types of bridges, thus as consequence, the construction cost also becomes relatively cheaper. Therefore, the community-based construction may be applied to construct its type of the suspension footbridges. Unfortunately, due to their long span, slender and moderate weight, the footbridge construction has excessive vibration caused by the induce moving load such as pedestrian and motorcycle movements. This condition, however, will seriously unsafe when the footbridges are used for tsunami evacuating to the safe zone, such as in Padang city area. In this study, a simple Tuned Mass Damper (TMD) is proposed to reduce such kind of excessive vibration of the suspension footbridge mentioned above. The TMD is composed of the mass concrete and used the motorcycle or light car spring. The dynamic analysis by using the computer code based on the finite element method has shown the promising results. The excessive vibration of the analytical model of the suspension footbridge is significantly reduced. Its reduction is shown by the reduction of the vertical deformation of the suspension footbridge up to more than 90% compared to suspension footbridge without TMD. The type of suspension footbridge which using the current proposed TMD is recommended to be used in the tsunami-prone area such as for Batang Arau in Padang city.