Experimental Study of Load Capacities of Tubular Steel Adjustable Shores Used in Construction

In this study, experimental tests were performed to investigate the load capacities of tubular steel adjustable shores in setups typically employed in construction sites, both for isolated units and combined systems. As for isolated units, the column curves of isolated tubular steel adjustable shores for a wide range were presented based on the test results. These curves can be used for interpolating the strength of tubular steel adjustable shores in design, instead of relying on extrapolation that may lead to uncertainties. The test results show that the overlap length between the connecting tube and base tube of the shore does not affect substantially the load capacity. Additionally, the load capacity of a 3-section tubular steel adjustable shore is lower than that of a 2-section shore. The load capacity of tubular steel adjustable shores decreases when No. 3 steel bars, instead of tube locks, are used. As for the combined systems, the reinforcing effect for a tubular steel adjustable shoring system with less than 16 shores is negligible when reinforced horizontally. For a tubular steel adjustable shoring system with four shores, the reinforcing effect is obvious when reinforced both horizontally and diagonally. This study also introduces the novel concept of upper and lower limit values of load capacity, which embrace the maximum and minimum strengths of all tested shoring members randomly selected for testing at the construction site. This concept can be potentially applied in shoring design.