Study on in-plane mechanical performance of poplar LVL orthogonal rib-beam floor

Abstract

This paper presents an experimental and theoretical study on the in-plane mechanical behavior of orthogonal ribbed beam floors made of poplar Laminated Veneer Lumber(LVL) and Oriented strand Board(OSB) panels. Eight full-scale specimens with plane dimensions of 4800 mm×3600 mm were designed and fabricated. Four-point bending tests were carried out to investigate the bearing capacity, in-plane stiffness, ductility of the floor by considering the rib-beam height, loading direction and floor type. The New Zealand standard NZSEE-2006 was employed to develop the formula for calculating the mid-span deformation of a floor specimen. It was found that the main failure modes of the floor specimens were slip, tilt and pull-out of the nails between the poplar LVL rib-beam and OSB panels. The internal rib beams and connectors of the specimens were largely intact. When the height of the rib-beams was the same, the stiffness, bearing capacity and ductility of the box floor specimens were better than those of the traditional floor ones. Increasing the height-span ratio of rib-beam could effectively improve the in-plane structural performance of a floor specimen. The bearing capacity of the same traditional floor specimens or box floor ones loading along the short side was higher than that loading along the long side. The formula for calculating the horizontal lateral displacement of the floor span was established by using the modified equivalent beam theory. The theoretically calculated values were in good agreement with the experimentally testing results.

Keywords

• Poplar LVL floor
• Orthogonal rib-beam
• Ultimate bearing capacity
• In-plane stiffness
• Ductility