Block-span method of roofing structures assembling

Abstract

The currently used block-conveyor assembling method requires costs for creating an area for blocks conveyed assembly and applying special assembly-and-lifting equipment and tooling; the erection of reinforced-concrete structures by large-sized prefabricated blocks is not possible without a special cross frame and guide casing, imitating a truss structure. The purpose of the research is designing a block-span method of assembling reinforced-concrete roof structures for one-storey industrial buildings, which would allow increasing the labor productivity, ruling out the usage of cranes with increased lift capacity for lifting blocks, reducing the scope of work at heights and increasing the building safety. The developed block-span method of mounting reinforced-concrete roofing structures with secondary trusses implies the assembling of an enlarged roofing block at ground level in the span between previously erected columns, through the full length and width of the span. The block includes secondary trusses, trussed rafters and roof slabs. The block is assembled on the backing 0.5 m high and 0.4…0.5 m off the center line and the width axis of the building. A block is a geometrically stable structure; all joints are connected by welding embedded items. A block is lifted by simultaneous activating of electric hoists. The block is lifted higher than the columns, moved to permanent position and put on top of columns by means of electric hoists. So, the developed method of roofing assembling allows reducing labor intensity by 1.6 times and duration by 1.4 times.