Faculty Sponsor Name

Mohammad Jonaidi, PhD

Abstract (300 words maximum)

Post tensioned concrete is a widely used method in the construction of the slab of high-rise buildings, podium (transferred) slab of wood-framed structures, bridges and so on. The effects of slab shortening due to concrete shrinkage and post-tensioning compression should be considered in the design of the structure. Various connections, between slab and wall, are used in the industry. However, the behavior of a special connection which consists of steel reinforcement dowels wrapped with compressible material has not been investigated. This research study investigates a case that requires a permanent slip detail in which the dowel between the shear wall and slab is wrapped with a compressible foam in different conditions. A unique testing rig has been established at the Kennesaw State University (KSU) Marietta Campus to apply lateral load to the poured concrete specimens that contain the foam-wrapped steel dowel (rebar), which extends into a poured concrete slab. A set of experiment was performed using a hydraulic jack, and load and displacement sensors. In the first specimen, both vertical and horizontal part of the rebar were wrapped. The result indicated that the wrapped bars still provide nearly 9,000-lb resistance before the 1 inch gap is closed. The specimen resisted a maximum of approximately 15 kips force ultimately. In the second specimen, the horizontal (hook part) of the reinforcement was unwrapped, allowing a bond between concrete and steel. The connection in this specimen behaved considerably different than the connection of the first set. The specimen resisted a maximum of approximately 39 kips. This reveals a remarkable aspect of this connection type. Further experiments are required, and planned, to be carried out to fully investigate and analyze this phenomenon.

Project Type

Poster

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A Special Slab-Wall Connection in Post-Tensioned Concrete

Post tensioned concrete is a widely used method in the construction of the slab of high-rise buildings, podium (transferred) slab of wood-framed structures, bridges and so on. The effects of slab shortening due to concrete shrinkage and post-tensioning compression should be considered in the design of the structure. Various connections, between slab and wall, are used in the industry. However, the behavior of a special connection which consists of steel reinforcement dowels wrapped with compressible material has not been investigated. This research study investigates a case that requires a permanent slip detail in which the dowel between the shear wall and slab is wrapped with a compressible foam in different conditions. A unique testing rig has been established at the Kennesaw State University (KSU) Marietta Campus to apply lateral load to the poured concrete specimens that contain the foam-wrapped steel dowel (rebar), which extends into a poured concrete slab. A set of experiment was performed using a hydraulic jack, and load and displacement sensors. In the first specimen, both vertical and horizontal part of the rebar were wrapped. The result indicated that the wrapped bars still provide nearly 9,000-lb resistance before the 1 inch gap is closed. The specimen resisted a maximum of approximately 15 kips force ultimately. In the second specimen, the horizontal (hook part) of the reinforcement was unwrapped, allowing a bond between concrete and steel. The connection in this specimen behaved considerably different than the connection of the first set. The specimen resisted a maximum of approximately 39 kips. This reveals a remarkable aspect of this connection type. Further experiments are required, and planned, to be carried out to fully investigate and analyze this phenomenon.