Cyclic response of slender RC columns typical of precast industrial buildings

Abstract

The cyclic behaviour of slender cantilever columns in full-scale models of precast industrial buildings, designed by Eurocode 8, was studied experimentally and analytically. The shear span ratio of the columns was 12.5, which is more than allowed by Eurocode 8 for columns in frame structures (10). High deformability and a large deformation capacity (8% drift) of the columns was observed. A lumped plasticity model was used in the analysis. In the paper the observed behaviour of the models has been compared with the predicted behaviour obtained by several empirically based models and procedures. It was observed that these models, which were developed for much lower shear span ratios (2-6), were not applicable for the analyzed very slender columns without appropriate additional considerations and modifications. In the case of such columns the yield drift is dominated by the flexural mode (it is practically proportional to the height of the column) and the ultimate drift under cyclic loading conditions is only slightly dependent on the shear span (indicating that the ratio of the equivalent length of the plastic hinge to the height of the column decreases with the increasing shear span). An appropriately modified lumped plasticity model incorporating in-cycle and repeated-cycle strength deterioration was chosen for future use in performance-based design and seismic risk studies.

Development of computing environment for the seismic performance assessment of reinforced concrete frames by using simplified nonlinear models

“…Elwood and Moehle 2008;Mergos and Kappos 2008). Also, many different procedures for the determination of the moment-rotation relationship or hysteretic models exist (Haselton 2006;Fischinger et al 2008;Fardis and Biskins 2003;Ibarra et al 2005;Zevnik 2007), but only two procedures are implemented in the present version of the PBEE toolbox. However, the user can change the existing procedures or add new functions for the determination of the moment-rotation relationship, functions for performance assessment by other simplified nonlinear methods, as well as other functions for pre-and post-processing of the analysis results, e.g.…”

Seismic collapse risk of precast industrial buildings with strong connections

“…This means that the absolute energy dissipation capacity of the slim columns increases compared with the capacity of short columns practically in proportion with the increase in the yield drift. Using this slightly modified procedure (described in detail in [15]) very good agreement between the numerical and experimental results was obtained (Figure 4). …”

“…Haselton has provided an expression for the secant stiffness to yielding rather than for the yield drift directly. Although the expression for stiffness is directly dependent on the shear span, the corresponding yield drift is practically independent of the shear span for columns with low axial loadings close to zero [15]. Such relation is more or less valid for columns with smaller shear spans, where the drift due to shear and bond-slip of the reinforcement at the base is dominant.…”

“…Such relation is more or less valid for columns with smaller shear spans, where the drift due to shear and bond-slip of the reinforcement at the base is dominant. However, in columns having a high shear-span ratio, the flexural component prevails over the deformation due to shear and bond-slip [15]. Yield drift is therefore practically proportional to the height (shear span) of the column.…”

Estudio Experimental Y Numérico De La Capacidad De Deformación De Soportes Esbeltos De Hormigón Armado

“…Por consiguiente, es necesario aplicar definiciones precisas para determinar dicho punto. La definición más clara en los métodos aplicados en este estudio es la propuesta en el Eurocódigo-8 [59] y ha sido utilizada en diferentes estudios [61]), ya que condiciona el punto de plastificación a una deformación límite del hormigón o del acero en la que cualquiera de estos dos materiales marca el inicio de su comportamiento inelástico. Una ventaja de la definición de punto de plastificación con el criterio de deformaciones es el efecto de la concomitancia de los diagramas M-φ y P-δ, lo cual garantiza también la concomitancia entre el desplazamiento y la curvatura en el punto de plastificación.…”