Load-carrying capacities of isolated tower scaffolds used in construction

During the construction stage of a building with high clearances, large spans and thick slabs, the isolated tower scaffolds which have higher load-carrying capacity are often considered to serve as the falsework and meet the load demand of the building. Because isolated tower scaffolds served as temporary supports are immediately removed after finishing the construction stage, the importance is often neglected. Up to now, the information on the structural design of isolated tower scaffolds has been rather scarce, and the assembly of isolated tower scaffolds on construction sites still relies mainly on the experienced workers. This phenomenon results in a high risk of collapse in actual application of isolated tower scaffolds on construction sites. This study explores the critical loads and the failure models of isolated tower scaffolds in various setups by testing actual installations of isolated tower scaffolds based on construction sites. The research results show that the base screw jack has a limited effect on the overall load-carrying capacity of isolated tower scaffolds. When isolated tower scaffolds are set up on ground with different elevations or on ground under an inclined top slab with varying elevations, the load-carrying capacity is not affected evidently if the elevation is less than half meter. On construction sites, when assembled in multiple layers, the isolated tower scaffolds are often installed with steel tube shores on the top layer. However, this combined shoring structure substantially reduces the load-carrying capacity of isolated tower scaffolds. In this case, directly extending the top screw jacks of the isolated tower scaffolds is better than using a combined shoring structure. As to the depreciation of repeatedly used tower scaffolds, this study conducts a repeated loading test to simulate the lower bound strength of isolated tower scaffolds on construction sites.