ACI 550.4-18 Qualifcation of Precast Concrete Diaphragm Connections and Reinforcement at Joints for Earthquake Loading (ACI 550.4-18) and Commentary (ACI 550.4R-18).
1.3—Structural drawings Structural drawings for the test modules shall show all features of the members into which the connectors or rein- forcement at joints are cast and all details of the connectors or reinforcement at joints essential for accurate representa- tion of the likely performance of the connectors, the rein- forcement at joints, and the connection. Essential details include: a) The anchorage of the connector or reinforcement at joints into the test panel b) The procedures and materials by which the connection between connectors, or reinforcement at joints, in adjacent panels of the module shall be made c) Confning reinforcement specifed as necessary for the proper performance of the connectors or reinforcement at joints d) Supplemental reinforcement that shall be included in the test panels to ensure that the performance of the member during the testing does not materially afect the measured response of the connections or reinforcement at joints 1.4—Units The ofcial version of this standard is in the English language using inch-pound units published by the American Concrete Institute.
R4.1—Test modules An idealized precast concrete diaphragm and its connec- tions are shown in Fig. R4.1a. The diaphragm consists of interconnected double-tee (DT) members spanning parallel to seismic-force-resisting structural walls whose dimensions are shown as thick solid lines in Fig. R4.1a(a). The exterior ends of the DTs are supported on spandrel beams and the interior ends are connected over an inverted tee beam that spans between the structural walls. Collectors at the ends of the structural walls help drag the diaphragm forces into the structural walls. The gravity load supporting columns for the spandrel beams and the inverted tee beam are not shown. There are two typical diaphragm connections” the chord connection and the web connection. Chord connections (Fig. R4.1a(b) and R4.1a(c)) transmit primarily axial tensile and compressive forces and are, therefore, subjected to displace- ments transverse to the longitudinal joints of the DT. Web connections (Fig. R4.1a(b)) transmit primarily shear forces and are subject to displacements both transverse and parallel to the edge of the DT fange. The test modules should be able to replicate the geometric and mechanical properties of the precast concrete fanges in the vicinity of the connec- tions and any reinforcement in those fanges in the vicinity of the connections. The connectors embedded in the fanges should be aligned within the test module in the same manner and to the same tolerances as those specifed for a prototype diaphragm using those connections. As is the case for anchors, connector behavior is controlled by the tensile strength of the material and not its yield strength. Because limits are set on the allowable varia- tion in the ultimate tensile strength of connector materials, no limits are set on the allowable variation in their ultimate elongations. The variation in the ultimate elongation for steel samples with the same specifed ultimate strength can be relatively large.ACI 550.4 pdf download.