An experimental study of flange-to-flange connections of double-tees was conducted as part of the PCI- funded research effort in developing a seismic design methodology for precast concrete diaphragms. The research program categorizes the strength and deformation capacity of common double-tee flange and chord connections under monotonic and cyclic loading. This paper focuses on the tension response of connections compared with design expectations and the contribution they provide in flexural resistance of the diaphragm. The pretopped flange connections were found to resist a moderate tensile force over a large deformation range. Flange connections topped-diaphragm systems provided a high initial tensile resistance but returned to the untopped response once the topping reinforcement failed. The strengths of both chord and flange connections were overpredicted by PCI equations due to brittle modes of weld failure. Consequently, attention should be paid to field weld alignment, and simplified models were developed to more accurately estimate the deformation capacity and strength.
