FULL-SCALE TESTING OF PRECAST CONCRETE SANDWICH PANELS

This paper describes newly developed precast concrete sandwich panels. The panels use a new system of fiber reinforced plastic (FRP) connect ors, developed at the University of Nebraska's Center for Infrastructu re Research, for transferring shear forces from one concrete wythe to the other. The use of FRP as the connector material increases the ther mal efficiency of the panels compared to panels that contain steel at concrete connectors. The geometry and material properties of the new c onnector provide sufficient strength and stiffness for a significant t ransfer of shear between the two concrete wythes. The results of struc tural tests are analyzed and design recommendations are presented. Des cription of an accompanying thermal performance testing of these panel s is also included. Four full-scale specimens were tested in a vertica l position. Two of the specimens contain the new FRP connectors, and t wo contain steel truss connectors. Measurements of load versus panel d eflection and load versus connector stress are provided. The ultimate strength of the panels containing the new connector were found compara ble to the strength expected of fully composite panels. The design of panels containing the proposed FRP connecting system can be undertaken in a manner similar to that of fully composite panels. Ultimate stren gth of the panels can be computed assuming full composite action betwe en the concrete wythes, if sufficient shear connectors are provided an d the panels are not over-reinforced.