Design of Precast Diaphragm Chord Connections for In-Plane Tension Demands

Seismic design of precast concrete diaphragms. a guide for practicing engineers

“…This feature reduces the resiliency of the connection under cyclic loads and is recommended only for use as a low-deformability detail (see Section 8.1). Special caution is required in the design of this connection to evaluate the eccentricities in the load path and the effects on the welds (Cao and Naito 2007). To overcome the limitations of this detail, to remove the intentional eccentricity in the path of the forces, and to provide a "fuse" through a ductile link with yield strength less than that of the embedded reinforcement or the welds and the erection jumper plate, commercial assemblies have been developed and tested to provide high-deformability chord connections for untopped double tee diaphragms.…”

“…Responses of conventional diaphragm joint connections in tension ) and in shear ) were determined. Additional details on chord connections were developed (Cao and Naito 2007) and commercially available connections were tested to characterize their strength, stiffness, and deformation capacity. Details on connection tests can be found in the sidebar.…”

“…Experiments were conducted using a variety of subassemblies that do not necessarily conform to the qualification requirements of Section 8 of this Guide. Experimental data have been generated on bent reinforcing bar hairpin connections (Venuti 1970;Kallros 1987;Naito et al 2009), welded plate connections (Pincheira et al 1998;Naito et al 2006;Cao and Naito 2007), angle plate connections (Spencer and Neille 1976), and a number of proprietary connections. Many of these connection test data sets are summarized in (Oliva 2000;Naito and Ren 2008;Cao and Naito 2009;Ren and Naito 2013).…”

Seismic Design Methodology Document for Precast Concrete Diaphragms

“…Under seismic demands a floor diaphragm system is subjected to a spectrum of relative motions. Analytical studies on the precast concrete diaphragm response to seismic demands 16 have shown that the connection displacement history is dependent on the location within the diaphragm. Connections located at the mid-span of the diaphragm are subjected to high flexural demands while connections located at the boundaries are subjected to high shear demands with minimal tensile opening.…”

An evaluation method for precast concrete diaphragm connectors based on structural testing

“…Under seismic loading, a floor diaphragm system is subjected to a spectrum of relative motions. Analytical studies on the precast concrete diaphragm response to seismic loading 16 have shown that the connection displacement history depends on its location within the diaphragm. Connections located at midspan are subjected primarily to flexure, while connections at the edges are subjected primarily to shear with minimal tensile opening.…”