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Gateway Park Center PERKINS+WILL <br /> 810495.00 <br />12/06/18 <br />031000-12 Concrete Formwork <br />3.2 SHORES AND RESHORES <br />A.Comply with ACI 347.2R for shoring and reshoring in multistory construction, and <br />as specified herein. <br />1.For non-post tensioned flat plate concrete structures of five supported <br />levels or more, extend shoring/reshoring at least four levels below the <br />floor or roof being placed (shore formwork, reshore three levels below) <br />2.For non-post tensioned flat plate concrete structures of less than five <br />supported levels, extend shoring/reshoring to ground. <br />3.For all other concrete structures of four supported levels or more, extend <br />shoring/reshoring at least three levels below the floor or roof being placed <br />(shore formwork, reshore two levels below) <br />4.For all other concrete structures of less than four supported levels, extend <br />shoring/reshoring to ground. <br />5.For shoring/reshoring placed on mud sills, adjustments shall be made by <br />contractor to account for ground settlement. <br />6.Locate shores/reshores such that the factored (ultimate) construction load <br />imposed onto any slab or beam at any time during the construction cycle <br />does not exceed 90% of the factored (ultimate) design load for that slab <br />or beam, scaled down to reflect effect on capacity of lower concrete <br />strength at time of loading. <br />7.Construction load shall include the weight of wet concrete, total weight of <br />formwork and shoring/reshoring, and a minimum construction live load of <br />50 psf (2.5kPa) (increase if construction operations will produce higher <br />loading). Design load includes self-weight of the slab, and superimposed <br />dead and live loads as indicated on the drawings. <br />8.For comparison of construction loads to design loads, compare factored <br />(ultimate) construction loads to factored (ultimate) design loads. For <br />construction dead and live loads, use the same load factors and load <br />combinations as required by ACI 318 for design dead and live loads. The <br />specified strength reduction factors from ACI 318 should also be applied <br />during the strength evaluation of the partially completed structure. <br />9.For flat plate or flat slab construction “backshores” or “preshores” as <br />defined in ACI 347 shall be permitted only if appropriate calculations and <br />construction sequences are provided demonstrating that the <br />accumulation of shore loads will not overload any slab. In the absence of <br />such calculations and construction sequences, shores must be removed <br />and reshores installed in a sequence such that each floor is permitted to <br />deflect and carry its own weight prior to the installation of reshores. <br />10.Reshores shall not be removed until the concrete has attained its <br />specified 28 day strength. <br />3.3 REMOVING FORMS <br />A.Formwork not supporting weight of concrete, such as sides of beams, walls, <br />columns, and similar parts of the work, may be removed after cumulatively curing <br />at not less than 50oF (10oC) for 12 hours after placing concrete, provided <br />concrete is sufficiently hard to avoid damage by form-removal operations, and