An experimental and numerical investigation on the cyclic response of a portal frame pier belonging to an old reinforced concrete viaduct

Abstract

This paper deals with the assessment of the seismic response of a portal frame pier belonging to an old reinforced\ud concrete viaduct. A series of tests, consisting of cyclically imposed displacements, were carried out\ud on three 1:4 scale mock-ups. The objective of the experimental campaign is twofold: (1) identification and evaluation of the local failure mechanisms and (2) calibration of a numerical model including all observed nonlinear phenomena. The experimental results show that the shear strength of the transverse beam and of\ud the beam–column joints characterizes the post-elastic behavior of the piers. Other phenomena, like bond-slip\ud and buckling of the longitudinal bars of the columns, typical of old reinforced concrete structures have also\ud been observed. Finally, a numerical model, built in OpenSEES, was calibrated to reproduce in a satisfactory\ud way the experimental results and to provide a reliable tool for the evaluation of the seismic response of the\ud pier

Accuracy of nonlinear static procedures for the seismic assessment of shear critical structures

“…The bent is thus a typical shear critical structure. This was confirmed by the quasi‐static cyclic test on the 1:4 scale specimen #1 that exhibited a shear failure of the intermediate transverse beam . The tested specimen has two circular columns 3.1 m in height connected by a cap beam on the top and an intermediate link beam with a span of about 1.6 m. The link beam plays an important role in reducing the bending moment on the columns and the lateral displacements.…”

“…Such an approach represents an added value in the estimation of the accuracy of the assessment procedures. Furthermore, to avoid including in the bias estimations the approximations related to the MDOF effects, two SDOF systems have been selected in this study: a shear critical frame used as deck support in a typical Italian bridge tested by Paolacci and Giannini and a flexure‐critical pier typical of a Caltrans bridge tested by Hachem et al . .…”

Assessment of the Seismic Behaviour of a Retrofitted Old R.C. Highway Bridge Through PsD Testing

“…More details on geometrical and mechanical characteristics of the viaduct can be found in Paolacci and Giannini (2012). Preliminary numerical simulations of the earthquake response of the as-built bridge, which will be presented in a companion paper, has shown for piers 9 and 11 (see also Fig. 14.2b) flexural failure of the columns, especially at beam-to-column and base-column sections, and widespread shear brittle ruptures in the transverse beams.…”

Numerical Seismic Assessment of an Existing Bridge With Different Support Configurations

“…A typical bond-slip behavior in terms of -slip directly derived from pull-out tests have been adopted to characterize the link elements along the bar and in correspondence of hooked anchorages [21]. These elements have been inserted in each node of the mesh between the concrete and the truss elements adopted for the longitudinal reinforcements.…”