Análise dinâmica de passarelas de pedestres mistas (açoconcreto)com aberturas na alma das vigas de aço.

Abstract

Height limitations are frequent in multi-storey buildings due to zoning regulations, economic requirements and aesthetical considerations. Moreover, to provide for the passage of large diameter pipes in steel beams a high ceilings is usually required. The most adopted solution is the use of holes in the steel beams web in order to enable the passage of services. Therefore, the main objective of this research work is to evaluate the dynamic behaviour of footbridges, where structural design includes the use of cellular steel beams. The present study was carried out based on a load model developed to incorporate the dynamic effects induced by people walking. In this load model the transient effect due to the human heel impact was considered and the position of the dynamic load is changed according to individual position. The investigated structural model was based on a series of steelconcrete composite footbridges, with main spans varying from 10m to 30m. The proposed computational model, developed for the structural system dynamic analysis, adopted the usual mesh refinement techniques present in finite element method simulations, based on the Ansys program. The footbridges dynamic response was investigated considering two different design solutions: beams filled soul and cellular beams. The influence of the holes in the composite beams web over the footbridges dynamic response was investigated and the peak accelerations were obtained and compared with results supplied by design codes and recommendations aiming human comfort evaluations.