This paper presents the development of models and the analytical study of the structural response of deteriorating unbonded posttensioned beams, with the aim of providing suitable tools for the evaluation of existing deteriorated structures. The corrosion phenomena of the tendons are reviewed in the introduction. Two modeling approaches are proposed: (1) beam macro finite-elements (MFE) using cross-section analysis and (2) two-dimensional (2D) nonlinear finite-element (FE) analysis. The corrosion attack modeling considers tendon-breaking and ductility-reduction of the prestressing and mild steel. Bond deterioration is also considered for the ordinary reinforcement. The models are validated by simulating three tests on corroded beams with unbonded prestressing wires, part of the Rance benchmark exposed to 40 years of attack in a natural marine environment, and then tested for imposed loading in the laboratory. The results obtained for the global response show a good agreement with the tests at all stages o...

Strengthening of flat slab-column connections to resist imposed lateral drifts is often required for older reinforced concrete structures in which the flat slabs were typically designed to resist gravity load only or have been designed for less stringent requirements. The complex stress state around the columns means that strong experimental evidence is required for the repair and strengthening techniques to be adopted with confidence in practice. Although a significant amount of research has been devoted to strengthening of slab-column connections, a series of limitations still remain. A thorough literature review revealed that only relatively thin and isolated specimens have been tested under seismic-type loading and realistic strengthening scenarios. To overcome these limitations, a full-scale two-story flat slab building specimen was tested at the European Commission’s Joint Research Centre – ELSA Laboratory in Ispra, Italy. This paper describes and analyzes the results obtained from the last of a series of phases, on repaired and strengthened internal and external slab-column connections using post-installed bolts. Compared with previous tests, the full-scale building specimen has a thicker slab (200 mm), realistic slab continuity conditions and the connections were strengthened after they suffered damage from gravity loading and previous lateral loading phases. The results show that post-installed bolts are efficient even under the described conditions (i.e. damaged and repaired specimens with realistic thickness), and punching shear failure was prevented in the strengthened connections.