ACI 550.5– 18 Code Requirements for the Design of Precast Concrete Diaphragms for Earthquake Motions (ACI 550.5-18) and Commentary (ACI 550.5R-18).
1.3—Structural drawings Structural drawings for precast concrete diaphragms shall show all features of the members into which the connec- tors or reinforcement at joints are cast that are essential to the intended seismic performance of the diaphragms and all details of the connections or reinforcement at joints essential for attainment of that intended performance. Essential details shall include: a) The anchorage of the connectors and reinforcement at joints into the precast concrete member b) The procedures and materials by which the connection between connectors in adjacent members shall be made and the tolerances that are acceptable c) Supplemental reinforcement that shall be included in the precast concrete members to ensure that the performance of the member under earthquake loading does not materially afect the measured response of the connections between members d) The methods to be used to ensure composite action, as specifed in the design, between topping and precast concrete member e) The connection of the collectors and the adjacent precast concrete members to the vertical elements of the seismic-force-resisting system f) The quality control and special inspection procedures governing placement of connectors and completion of connections.
4.2—Materials 4.2.1 Design properties for concrete and steel reinforce- ment shall satisfy 12.2.2 of ACI 318-14. Material strengths specifed for connectors shall be within 10 percent of the specifed strengths used for those connectors in the qualifcation tests conducted in accordance with ACI 550.5-18. Concrete strengths specifed for the precast concrete elements of the diaphragm shall be within 25 percent of those used for those elements in the qualifcation tests conducted in accordance with ACI 550.5-18. 4.2.2 The minimum reinforcement ratio and the spacing of reinforcement in topping slabs shall satisfy of ACI 318-14. 4.2.3 The stress in tendons used as reinforcement to resist earthquake loading shall satisfy and of ACI 318-14. 4.3—Minimum thickness 4.3.1 Diaphragms and diaphragm toppings shall have thickness as required for stability, strength, and stifness under factored load combinations and shall satisfy 12.3 and 18.12.6 of ACI 318-14. 4.4—Tolerances 4.4.1 Tolerances for positioning and completion of connections between the precast concrete elements of the diaphragm shall not exceed ±1/2 in.ACI 550.5 pdf download.