Technical Feasibility Study of the Use of Softwoods in Lattice Structure “Howe” Type for Roofing (Gaps between 8-18 Meters)

Introduction: Wood is a material of biological origin widely used in construction, and its mechanical properties allow the material to form the lattice structure of roofs used in warehouses of industrial use, however, the paradigm as to the behaviour of the material makes the design decision less susceptible.

Aims: This work intends to verify the feasibility and optimize the use of unconventional wood in triangular roof truss structures in regions of flat topography, with a characteristic wind speed of 30 m/s.

Methods: The design methodology was fully based on the recommendations of ABNT NBR 7190

For the elements dimensioning, it was necessary to define the geometric and structural parameters that directly influence the actions and loads, as well as the behaviour of the structural elements.

Results: The choice of wood in this context, it was proposed the elaboration of projects of roofing structures with the following characteristics: "Howe" latticework (inclination of 10º - steel roof tile); Spans of 8, 10, 12, 14, 16 and 18 meters (ratio width: length, in plan, environment of 1: 3); Typology of the lateral openings of the building - (relationships between main opening area: other openings) 1:1, 2:1, 6:1 and insulated coverings (coverage on a medium of reduced dimensions).

Conclusion: The ratio of the volume of wood per floor area (m³.m-²) for C20 and C30 grade timber was determined, as well as the consumption of metallic pins per floor area, following the requirements of Brazilian standards, proving the technical feasibility.