Shear effects on hollow section piers under seismic actions: experimental and numerical analysis

Abstract

Shear effects are often a very important issue on the seismic behaviour of piers, particularly for hollow section bridge piers. In fact, for this type of piers the cyclic response is similar to that of a structural wall in which both the transverse reinforcement ratio and the detailing can play an important role on its performance, even likely to be determinant in terms of the failure mechanism. On the other hand, codes and design guidelines are usually very conservative concerning shear capacity in order to avoid any shear failure mechanism likely to trigger well known catastrophic consequences. Therefore, research studies on this topic are still needed for a better understanding of pier cyclic shear response and also for improvement of the performance under seismic actions. Pursuing this general objective, this paper partially reports on an experimental/numerical campaign carried out on 1:4 reduced scale bridge piers in order to highlight and investigate shear-type problems. Within the scope of this paper, two specimens types were selected having equal rectangular hollow section (900 × 450 mm 2 , 75 mm thick) but different transverse reinforcement detailing, namely one with a single stirrup per wall (representative of typical bridge construction without seismic design requirements) and another with multiple stirrups, according to Eurocode 8 provisions. Numerical simulations of the experimental results were also conducted aiming at contributing for complete and consistent interpretations of experimental results. Detailed modelling was performed allowing for realistic simulations of the non linear behaviour, particularly suitable when a significant shear component is involved. Therefore, the numerical strategy was based on a detailed 3D FEM discretization using a two-scalar variable damage model for 123 378 Bull Earthquake Eng (2009) 7:377-389 the concrete constitutive law and a suitable cyclic behaviour law for steel bars represented by truss elements. Results have shown that shear deformation and failure modes are well simulated, while providing detailed insight concerning concrete damage pattern and distribution of yielding on the transverse and longitudinal reinforcement.

Cost of Repair and Retrofit of Seismic Damage of Rc Hollow-Piers

“…At the same time, it was identified that this evolution of the cost is potential, being translated by equation (1).…”

“…This paper focus on the analysis of damages on hollow piers due to the seismic action, proposing a methodology to characterize the limit states of damage under the perspective of the physical behaviour. To establish a correspondence between physical damage states and structural parameters, a set of results of quasi-static experimental tests was analysed, in hollow piers of reinforced concrete subject to cyclic loading [1][2][3].…”

Seismic Behaviour of Poorly Detailed Rc Bridge Piers With Hollow Cross-Section

“…Only quite recently, attention has been paid to experimental cyclic response of hollow columns: relatively few experimental studies, especially if compared with columns with solid cross section, are available in literature. Some of the existing studies [5][6][7][8] highlighted that the lateral response of existing (poorly detailed) hollow RC piers is characterized by high shear deformations, comparable to ones typical of RC walls, which may represent also a considerable portion of global top displacement. Calvi et al [5] observed that fiber models, good in capturing flexural response, needed corrections in order to include some stiffness reduction due to shear deformability.…”

“…Calvi et al [5] observed that fiber models, good in capturing flexural response, needed corrections in order to include some stiffness reduction due to shear deformability. Delgado and his colleagues [6][7][8] noted that shear deformation of hollow piers cannot be captured with typical models, based on fiber or plastic hinge approaches; therefore, they adopted a more advanced numerical tools, with 3D finite elements and complex constitutive models, to adequately reproduce the experimental response of poorly detailed RC columns, both in terms of load and deformability.…”

Experimental Cyclic Tests of Hollow Piers With Different Retrofit Strategies

“…The test setup characteristics and more detailed results are available in previous reports [1][2][3][4]. This set of specimens was based on square piers tested at the Laboratory of Pavia University, Italy [5,6], consisting on hollow section RC piers with 450mm x 450mm exterior dimensions and 75mm thick walls, and is being tested in order to understand the influence of the cross section geometry of rectangular hollow piers on the cyclic behavior, bearing in mind the purpose of assessing retrofitting solutions.…”