A new precast concrete sandwich panel system with a high thermal resistance and optimum structural performance has been developed. A hybrid truss provides the connector in this panel system - the diagonals are fiber-reinforced plastic bars and the chords are prestressed steel strands. Each connector consists of a fiber-reinforced plastic bar fabricated in a deformed spiral shape through which a pair of prestressing strands is threaded to provide anchorage in the concrete wythes. The developed shear connecting system is described together with its advantages. An experimental and analytical investigation of the connecting system was conducted. The experimental program included testing of small scale specimens by push-off (pure shear) loading, small scale specimens by flexural loading, and full scale panels by flexural loading. The analytical investigation included finite element modeling of the tested small scale specimens and comparisons with theory of elasticity solutions. Experimental and analytical results from finite element modeling and from theory of elasticity equations correlated well and showed that the developed panel system meets the objectives of the research and is expected to have a promising future.
