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Embedded plates are used to support external attachments such as heavy piping, brackets, sprinkler systems, or other equipment in concrete structures. The plates are typically welded with deformed reinforcing bars or deformed wires, which are embedded in reinforced concrete walls. The ACI Codes (ACI 318-19 and ACI 349-13) provide design equations to calculate the pullout strength of anchors in concrete under tension loading. However, these empirical equations are based on experiments conducted on headed studs, hooked bars, headed bolts, and adhesive anchors. With the lack of experimental data and resulting Code provisions on straight deformed reinforcing bars or deformed wires used as anchors, it is believed that anchoring bars with the embedment length as per the Code-prescribed development length will provide sufficient strength to transfer tensile forces to the concrete, ignoring other failure modes such as concrete breakout and pullout. The applicability of the concrete-governed adhesive bond model of ACI 318-19 for bonded anchors is evaluated to estimate the strength and failure modes of these connections. The current ACI adhesive bond model does not capture the correct failure mode and the influence of anchor spacing and bond strength on the capacity. The issue is addressed by incorporating the correction factor (g,N). This paper presents eight large-scale group-anchor test results to evaluate their concrete breakout strength and the applicability of the ACI 318-19 adhesive anchor/bond model to estimate connection capacities and failure modes. The mean average back-calculated effective k value is 33.3 for deformed reinforcing bar anchors (DRAs) and 36.5 for deformed wire anchors (DWAs). Single-anchor tests were also performed to evaluate the bond behavior per the ACI 318-19 uniform bond model. The experimental study confirms that the axial tension capacity of embedded plates anchored to concrete using deformed reinforcing bars or deformed wires can be limited by concrete breakout strength. The ACI bond model with the correction factor appropriately estimates the failure mode and strength of such connections. [ABSTRACT FROM AUTHOR]

Embed plates anchored with welded deformed reinforcing bars or heavy-gauge deformed wire are commonly used for attachments in nuclear facilities. These connections may experience significant tension and/or shear. The required embedment of the welded bars is typically determined based on development length concepts, with the assumption that the nominal tensile capacity of the connection can be taken as the tension yield strength of the bars. This paper presents results of large-scale experimental investigations conducted to evaluate the tensile capacity of such embed plates. Single anchor pullout test results are also presented to categorize bond behavior for deformed reinforcing bar anchors (DRAs) and deformed wire anchors (DWAs). Preliminary results indicate that adoption of the design paradigm given in the Code for the concrete-governed strength of bonded anchors can provide a reasonable approximation for DRAs but requires additional calibration and study for application to DWAs owing to their diminished bond capacity. [ABSTRACT FROM AUTHOR]