Well-designed and manufactured glass fiber reinforced polymer composite structures have several advantages over steel and conventional concrete structures such as high strength-to-weight ratio, good stiffness, good corrosion resistance and good damping capacity. In view of their higher cost however, their use is restricted to structures with smaller dimensions such as pedestrian walkways particularly where aggressive environmental conditions are encountered such as in chemical and water-treatment plants. The keys to success of these structures lie in the proper choice of the constituent materials, manufacturing method and knowledge of the behavior of the structure under the conditions encountered. Knowledge of the mechanical behavior is particularly important in this context. An investigation was therefore conducted by the authors, in partial fulfillment for the award of master of engineering science degree of Lamar University to the first author under the supervision of the second author , to study the response to loading of a glass fiber reinforced polyester composite structure made by the pultrusion process by a reputed manufacturer. The structure chosen for this study was a grating, the details of which are shown in the paper. This type of structure is particularly useful for walkways. The experimental part of the investigation consisted of subjecting the grating to three-point bend test under different loading conditions. The load-deflection curve for each case was obtained and interpreted. One grating was loaded up to failure and the fractured zone was examined using a scanning electron microscope to interpret the microscopic failure features. Simulation of the experimental work was carried out using an industry-standard FEM software to compare the deflection values. The results are presented and discussed in this paper.