Caracterização do bambu laminado colado para uso estrutural

Abstract

Bamboo presents itself as a promising organic material, which allows reducing the environmental impact and brings thermal comfort to construction. Its deconstruction into veneers brings usage flexibility, which transforms the bamboo into a engineering material. It was studied the influence of the gluing pressure on the shear strength for the bamboobamboo connection; the influence of the roughness on the gluing surface for the bamboobamboo connection; the physical and mechanical properties at room temperature of the Glued Laminated Bamboo (GLB) to define the elastic constant matrix, considering it as orthotropic material; and the mechanical properties at high temperature for destructive and non-destructive tests. This project sought, thus, to detail the GLB characteristics for structural use, assessing the bamboo interface with the adhesive, as to produce a structural material, through destructive and non-destructive tests at room temperature and high temperature. It was adopted the thermal hardener bicomponent resorcinol-formaldehyde adhesive and the Phyllostachys pubescens bamboo species. Firstly it was evaluated the best gluing pressure and, with these results, it was analysed the adhesive absorption, resistance and the shear strength tension on the connection breakup. To this end, some specimen were created applying the same adhesive with different crushings. Following that, it was evaluated the roughness on the gluing surface of these specimen. The veneers were submitted to sandpaper treatment and to cutting on a saw. As a third objective, it was detailed the physical characteristics of the bamboo, investigating density, moisture, retraction and the anisotropic factor of the specimens and then it was studied the mechanical characteristics of the bamboo and the GLB, firstly with compression destructive tests and, secondly through ultrasound and waves excitement non-destructive tests. As a last objective it was searched the GLB mechanical properties at high temperature. The chosen gluing pressure stemmed from the first objective was 2,5 MPa; due to cost-benefits, it was adopted the roughness of the surface cut by a common saw, it offered a good connection resistance. However, the best GLB performance was obtained through veneers superficial treatment using a 220 sandpaper, it was verified a 50 % gain on shear strength. As for the high temperature tests, it was verified a minimum 20 % and a maximum 50 % gain on the elastic modulus. The non-destructive test results presented themselves very similar to the destructive test results, which prove the usage possibilities for a simpler, cheaper and more efficient method. It was utilized the wood parameters to evaluate the GLB. The tests e the used methodologies to collect data followed the International Standard ISO 22157-1, EUROCODE and ABNT NBR7190: 1997 prescriptions. Such evaluation seeks to broaden the studies about GLB as a structure, verifying its potential as a new building system, opening new ways to use it. It brings an innovative scenario, as a parameter for engineers and architects, using natural materials, thus making an important contribution to sustainable development, also influencing the reduction of environmental impact.