Abstract: Panels have tensioning formations at their edges that are engaged upon support members via resilient compressive loadbearing elements. In the constructions shown the tensioning formations comprise integral, semicylindrical edge portions of the panels and the load-bearing elements comprise mating resilient rods inserted into the semicylindrical formations. The panels are relatively thin extrusions of transparent polycarbonate resin forming an acoustical barrier structure. Thermal expansion and contraction is accommodated by mutual action of the panels and the resilient load-bearing elements. A transparent acoustical barrier wall along a highway and a noise barrier canopy over a rapid transit line are shown.