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Typically, the columns of the prefabricated reinforced concrete (RC) industrial buildings and warehouses with large clear storey heights are very slender, with aspect ratios (shear span to width) larger than 10. In addition to supporting the gravity loads, the columns also provide strength, stiffness, dissipation and displacement capacity of the primary lateral-load resisting system. However, current empirical relationships that predict the non-linear response and failure mechanisms of RC columns have been developed mainly for lower aspect ratios (< 7), typical of ordinary multi-storey buildings or short-to-medium bridge piers. What makes slender columns different is their predominant flexural response, larger drifts at nominal strength and corresponding lower ductility demands, smaller ratios between the strain penetration and plastic hinge lengths to the element shear span and risk of P-Delta instability. Therefore, the direct application of analytical models available in the literature to slender columns poses a risk of overestimation of their deformation and dissipative capacity. In turns this could lead to the underestimation of their displacement demand, overall damage and collapse probability of the primary seismic-resisting and load-bearing system. In the present research extensive analysis on the non-linear response of slender columns was performed based on observed post-earthquake damage to buildings in Italy and Turkey, experimental data and numerical predictions of the failure patterns through non-linear fiber element models. The influence of the foundation flexibility and the presence of industrial floor was also investigated. The outcome is a simplified analytical methodology for the prediction of the non-linear force–deformation response and possible failure mechanisms of slender precast columns due to rebar buckling or P-Delta effects, as a fundamental step towards the seismic assessment of the global structural performance and cost-efficient retrofit solutions for precast concrete industrial buildings. [ABSTRACT FROM AUTHOR]

Haunch retrofit solution (HRS) has been investigated as a viable alternative for retrofitting of beam-column joints of reinforced concrete (RC) frame structures. For connecting the haunch elements to the frame members, partially prestressed rods were used. This solution, however, makes it difficult for implementation in practice due to the requirement of drilling holes through the slab. A more practical solution is to connect the haunch elements using post-installed anchors, resulting in fully fastened HRS (FFHRS). The solution has been tested at the subassembly level, and encouraging results were obtained. To verify the performance of the FFHRS to retrofit the frame structures subjected to real-life seismic loads, shake-table tests were performed on non-seismically detailed two-dimensional (2-D) RC frame structures. This paper presents the results of the experiments with the detailed discussion of the performance of the FFHRS under earthquake ground motions. [ABSTRACT FROM AUTHOR]