An experimental program has been carried out to investigate the structural behavior of adhesively bonded glass fiber reinforced polymer (GFRP) sandwich girders. The girders, conceivable for main spans up to 20 m, are composed of translucent double sandwich element webs and adhesively bonded pultruded shape flanges. The continuous adhesive connections between web and flanges are loaded in a highly favorable manner without peeling stresses. Despite the complex load-carrying and failure behavior of the girders, simple calculation models can be applied. The successful girder experiments allowed for the development of a material-adapted construction method for new GFRP bridges and buildings. The integration of architectural aspects such as transparency, translucency, lighting, and color, as well as building physical aspects for buildings such as thermal insulation, substantially increases the overall value of the proposed constructions. Together with the lower life-cycle costs, this further justifies these new materials' higher initial costs as compared with traditional materials.