Analysis of Eucalyptus Glued-Laminated Timber Porticos Structural Performance

Abstract

-This study evaluated the structural behavior of porticos made from eucalyptus glued boards, using wood of Eucalyptus sp and resorcinol formaldehyde adhesive. Three units, in real scale, of tri-articulated straight porticos, with a 5 meter porthole and a 26 º inclination, capable to support tiles covering placement were designed, constructed and subjected to load testing, until rupture. The amount of adhesive used in the construction of the porticos was 250 g/m 2 and the bonding pressure of 1.3 MPa. The Hankinson model was employed as an estimator of the glued joints strength, under different angles between the fibers. The average value for the last resistance of the structures was 4.63 times the design load, according to the criteria established by the ABNT, 1997. The structures showed satisfactory mechanical performance and deformations lower than the ones allowed by the standard. It was concluded there is technical feasibility to manufacture porticos fully bonded with small thickness veneers.

Construction and Testing of Glued Laminated Timber Frames for Use in Laying Poultry Houses

“…Figure 1 shows the scheme of specimens used for torsion testing on the glue line. The highlighted circular region (glued surface) is subjected to a torsional stress, allowing calculating the shear strength at breaking by applying a specific formula to the strength of materials (Couri Petrauski et al, 2016).…”

“…Column-beam binding requires bonding with a slope other than 0°, which is not included in the standard NBR 7190 (1997). For this reason, the methodology proposed by Petrauski (2000) and Couri Petrauski et al (2016) was used, allowing the quantification of a necessary bonding area to face the active stresses Md, Qd, and Nd through the glued areas AM, AQ, and AN.…”

“…When sizing glued timber structures, joints must have predictable behaviors and high strength levels to meet standards and requirements of each project. Moreover, conditions under which adhesive may have its performance optimized or bonding cannot be carried out must be known to avoid losing structure strength and/or durability (Couri Petrauski et al, 2016;Molina et al, Engenharia Agrícola, Jaboticabal, v.40, n.2, p.122-131, mar./apr. 2020 2016).…”

“…Couri Petrauski et al (2016) evaluated structural behavior of GLT frames using Eucalyptus sp. wood and two adhesives: castor oil-based polyurethane and resorcinol-formaldehyde.…”

“…Similar frames, built with the same technique suggested by Couri Petrauski et al (2016) and designed for use in laying poultry houses, were evaluated in this research. Parana pine from reforestation was also used, and changes in inertia were considered in the roof beams, aiming at saving wood.…”