Proposta de projetos de passarelas modulares para pedestres constituídas por perfis de aço formados a frio

Abstract

Economy in structural engineering design aims to reach both lower weight of its constituent elements and maximum structural efficiency. In this sense, the present study had the objective of proposing the structural design of modular truss pedestrian bridges constituted by cold-formed steel framing (closed U sections with lips and square hollow sections) to three distinct spans in highways from the National Department of Infrastructure and Transport. There had been stablished, firstly, the truss of Warren with verticals with a span of 25 meters as the structural system of interest, pre-designed the frames by maximum displacements and minimum radius of gyration, and determined the maximum applicable wind and temperature loads throughout the Brazilian territory, as well as the other applicable loads. In this study, there had been also investigated and presented the parameters related to accessibility in order to define the utilized dimensions. Sequentially, there has been executed the structural design of frames by the combinations of ultimate limit states through structural modeling in the SAP 200 software from Computers and Structures, Inc., which uses the finite element method. Additionally, there had been verified the maximum displacements and the minimum natural frequency of the floor structure from serviceability limit states. From the structural design, this study proposed typical intramodular and intermodular connections, as well as a standardization of manufacturing, anticorrosive treatment, transportation in simple trucks and assembly of three different modules, focusing on reducing time, cost and increasing the durability of structures. For the span of 25 meters, the total weight of the truss structure of the pedestrian bridge had been estimated at 75,50 kN.