MODAL ANALYSIS OF ALUMINIUM PLATE FOR SHORT SPAN FOREST BRIDGE DESIGN

Abstract

Stream crossing is one of the components in forest road construction to protect water quality during timber harvesting operations. Proper management of this network
allows the post harvesting activities in the way to manage the forest sustainably. Poor stream crossing design and improper installation lead to erosion and sedimentation that disconnect the accessibility to the harvesting area unless the bridge is repaired. The forest bridge usually is made of native log and left deteriorated at the end of the logging period. Therefore, this study focuses on a new concept of a bridge which emphasizes simplicity site installation and is capable of serving stream crossing at multiple sites. This study shows the short span forest bridge design for modal analyses by assessing dynamic properties of aluminum plate for light weight characteristic in portable bridge application. Comparison of natural frequencies and mode shapes for four boundary conditions show the capability of modal analysis to characterize the proposed design structure.