ANALYTICAL AND EXPERIMENTAL PERFORMANCE OF OPTIMIZED PULTRUDED FRP SHAPES FOR LONG-SPAN STRUCTURAL SCENARIOS

Currently available “I” and wide-flange (i.e., “W) pultruded FRP shapes for structural applications are limited in their geometric variety versus comparable rolled steel shapes. Most available pultruded FRP shapes in inventories are limited to 12 in. depths, I-shapes have flange widths that are half their section depths, and W-shapes exhibit uniform flange widths and depths (i.e., similar to steel shapes used as piles). Furthermore, all currently available I and W-shapes feature uniform web and flange thicknesses which are inefficient for long-span structural applications, leading to comparatively low ratios of buckling limit states strength to weight as well as increased deflections relative to weight. In collaboration with multiple pultruded FRP manufacturers, new 16-in. and 18-in. deep I-shapes were designed based on the following optimization parameters: minimizing the disparity between flexural strength and local instability by utilizing non-uniform web and flange thicknesses, maximizing the moment of inertia to area ratio, and limiting the difference between shear strength and web shear buckling. These two new shapes were then experimentally validated – with the 18-in. deep I-shapes having been tested as of writing – for their flexural strength and stiffness performance for long-span scenarios. The experimental testing not only validated their expected flexural performance, but also targeted parameters concerning current gaps in the design and testing standards for the flexural performance of structural pultruded FRP shapes.