An integrated study for hybrid composite beam (HCB) structures

The hybrid composite beam (HCB) consists of a self consolidating concrete (SCC) arch that is tied at the end by galvanized strands. The tied arch is encapsulated by a glass fiber reinforced polymer (GFRP) shell. A limited number of researches have studied the essential design methodologies and long-term performance of the HCB. The research presented in this dissertation aimed to more fundamentally understand the structural behavior of this new beam and evaluate its durability. This research study was conducted through four phases. A full-scale bridge load testing was conducted on a single-web HCB bridge during the first phase. The first finite element analysis of an HCB bridge superstructure was conducted. The areas that need more research and investigation were highlighted. In the second phase, double-web HCB Bridge was instrumented by various sensors. Strains induced in HCB\u27s elements during several loading stages were collected. The existing flexural analysis method was unable to estimate accurately the induce strains. Analysis methods for a simply supported HCB and an HCB that is supported on bearing pads were proposed. These methods achieved significant enhancement in estimating the HCB\u27s strains. The HCB\u27s shell was subjected to five aging regimes during the third stage. The existing voids in the laminated shell made the fibers and the interphase regions prone to chemical and moisture attacks. However, the diffusion of the chemical solutions was always found to be confined to the first lamina. This result suggested that the composite shell is able to protect the strands from a moisture attack during the HCB\u27s service life. The last stage clarified that the thermal stresses in an HCB bridge superstructure elements produced by thermal gradients are not critical and can be excluded from the design. --Abstract, page iv