The Performance Evaluation of Circular Flange Bolted Connection in Ultra High Performance Fiber Reinforced Concrete Segmented Communication Tower

This study herein presents investigations about behavior of circular flange bolted connection (CFBC) in ultra high performance fiber reinforced concrete (UHPFRC) hollow segmented communication tower subjected to lateral dynamic load. The CFBC consists of two flanged concrete, cast together with the structural segment tubes and then connected using steel bolts. The paper is illustrated with CFBC joint of 500mm flange thicknesses, and 8M25 high strength steel bolts coming from a typical real design tower. For this purpose, the full scale CFBC joints for communication tower are made from Ultra High Performance Fiber Reinforced Concrete (UHPFRC). The connection was cast and experimentally tested by applying cyclic lateral load using dynamic actuator. The lateral strength and stiffness resistance of the UHPFRC CFB connections were evaluated in this study. Besides, a rigorous FEM analysis was executed in order to evaluate the performance of CFBC in the communication tower by investigating the mechanism of force transfer, load bearing capacity as well as failure behavior of the circular flange bolted connection (CFBC) under lateral cycling loading. The experimental and numerical analysis results showed the ability of UHPFRC circular bolted connection to resist the applied lateral loads. In addition, the considered model revealed that for joints under tension, bolts were seriously not subjected to bending moments which is due to the prying effect. This was made possible by the provision of adequate flange thickness and strength of the UHPFRC material.