An experimental study of double-tee, flange-to-flange connections was conducted as part of the PCI/National Science Foundation–funded research effort on the development of a seismic design methodology for precast concrete diaphragms. The research program categorizes the strength and deformation capacity of common double-tee web and chord connectors subjected to in-plane shear or tension loading. This paper presents the experimental results of floor diaphragm connectors subjected to in-plane shear and in-plane shear with tension deformation. The results are compared with expected capacities. The majority of connections subjected to shear with opening restrained exhibited high compression forces coupled with high shear capacity. The application of tension, however, compromised the shear strength. The chord connections tested were found to provide high shear resistance over a limited deformation. Web connectors in topped diaphragm systems provided a high initial shear resistance but returned to the untopped response once the topping reinforcement was lost. The topping slab reinforced with welded-wire reinforcement exhibited brittle shear response with high initial stiffness and strength prior to wire fracture. To improve the connection strength and deformability, recommendations on connector detailingare presented
