Experimental Investigation of Lateral Stability of a Longitudinally Assembled Girder Made of Precast Reinforced and Prestressed Concrete Parts

This research focuses on the lateral stability (LS) of a longitudinally assembled girder (AG), constructed for both economic and constructional purposes. The AG features a central precast prestressed concrete (PPC) beam, 34.175 meters long, extended by two precast reinforced concrete (PRC) beams, each 2.63 meters long, connected by bolted joints. A gap between the joints was filled with high-strength grout to efficiently transfer compressive stresses. The experimental study considered two types of imperfections: initial lateral imperfections in the AG and the initial tilt angle between the connected surfaces. Three tests (AG1-A, AG1-B, AG2) were performed using nondestructive loading with concrete blocks to assess LS. The first two tests were conducted on AG1, keeping the initial imperfections consistent but varying the preload on the bolts, while the third test used specimen AG2, which had greater lateral imperfection at the mid-span cross-section. Test results showed that, due to the high preload, the tilt angle imperfection had a negligible impact on the AG's lateral stability, as separation at the connections was minimal. AG1, in tests AG1-A and AG1-B, remained laterally stable throughout the entire loading process, whereas AG2 experienced stability loss due to insufficient lateral restraints, significant geometric imperfections, and eccentric loading.