Experimental Investigation of Flexural Mechanical and Flexural Creep Properties of Sleeved PGFRP Composite Used in Transmission Tower Application

This research conducted was to investigate the flexural mechanical properties and flexural creep response upon pultruded glass fibre reinforced polymer (PGFRP) composite used in cross-arms for transmission tower application. A comparative study was done upon virgin and sleeve reinforced PGFRP composite to observe the enhancements within their elastic limits mimicking real-time scenario. The primary aim of this research was to enhance the service life of the material that fails due to long-term static loading. Hence, this research was investigated in a similar tropical environmental conditions subjected to working loads. The sleeves were made of stainless steel of SS304 structural grade and fastened by bolting using SS304 M4 bolts, as it would contribute to feasible fabrication, ease of installation and facilitates repairs in actual utilization. The specimens, mounted against the test rig and loading hooks, whose induced deflections were measured by Mitutoyo 2050A analog dial gauges. The mechanical and creep properties were observed from the 3-point bending experiment as the failure in real-time scenarios resembles flexural failure mode and further the data was used to evaluate elastic mechanical properties. The obtained results shows that the structural sleeve installation has enhanced the elastic modulus by 160.25% and 39.91% under instantaneous and creep load conditions respectively. In addition, the strain produced upon sleeved PGFRP has reduced by 61.60%, which can be attributed to increased brittleness of the specimen due to the addition of sleeve reinforcement, which thereby resists the deformation of the structure induced to load. These observations thereby contributes to improved functional working life of the cross-arms in transmission tower application.