Development of Rigging System for Prefabricated Wood I-joist Floor Panels

Abstract

Panelized building construction are highly mechanized. Material handling and lifting equipment dominate construction sites and constitute the critical element in achieving productivity. In recent construction practice, panelized wood I-joist floor panels are normally lifted into place by mobile crane using flexible slings inserted through the predrilled holes on the I-joist web and sheathing panels above the I-joist top flange and then wrapped around the I-joists at the four corners. However, the pre-drilled holes on the web and sheathing may weaken the floor panels. Moreover, a range of techniques for lifting and handling mass timber panels have been developed. A typical rigging technique consists of a lifting ring and a steel plate with pre-drilled holes. By using several self-tapping screws, the panel was connected with the rigging device for lifting. However, since prefabricated I-joist floor panels are much lighter than mass timber panels and the I-joist flange is relatively narrow and thin, the rigging device for mass timber panels cannot be applied directly to I-joist floor panels, but a modified design can be developed for prefabricated I-joist floor panels. In the present study, a new rigging device was designed for prefabricated wood I-joist panels and their load capacity was evaluated by withdrawal tests. Several factors influencing the withdrawal capacity were investigated including screw types and quantities, flange width and materials, and OSB thickness.