The effects of inelastic buckling on monotonic and cyclic behavior of reinforcing steel bars are studied. Experimental tests show that this phenomenon occurs when the ratio between length and diameter of the bar exceeds 5, and that it leads to a postyield softening branch in compression that strongly influences the cyclic behavior of the bar. An analytical model of rebars accounting for inelastic buckling is presented, suitable for inclusion in programs for the analysis of r/c sections using the fiber type of discretization. The model employs four hardening rules (kinematic, isotropic, memory, and saturation) as functions of four independent parameters (yield stress, elastic modulus, hardening ratio, and a weighing coefficient). An explicit stress‐strain relation in finite terms for loading branches is utilized. The model yields accurate results in predicting the cyclic behavior of rebars, both with and without inelastic buckling, for deformation paths of general nature.

The impact of the two seismic events of August 24th 2016 on the municipality of Amatrice was highly destructive. There were 298 victims, 386 injured, about 5000 homeless, and the historical center of the town suffered a great number of partial and total collapses. The 260 strong motion records obtained for the first event were analyzed and plotted in a shakemap, comparing them with the macroseismic damage surveys made in 305 localities. On the basis of an inspection survey made in September 2016, a map of the damage patterns of the buildings in the historical center was elaborated according to the EMS 98 classification. The damage level resulted very high with more than 60% of the inspected buildings showing partial or total collapse. The elevated level of destruction was mainly caused by the high vulnerability of the masonry buildings, mostly due to specific vulnerability factors such as the poor quality of masonry, the lack of connections between walls and the poor connection between external walls and floors.

This work presents the results of an extensive numerical study on the nonlinear response of bridges subjected to multisupport seismic excitation. Bridges of varying stiffness and ductility have been designed both for nonsynchronous motion and, as in current engineering practice, for synchronous motion, and have been subsequently analyzed in the nonlinear range under nonsynchronous input motion. The purpose of the study has been to assess the effects on the peak inelastic response of bridge structures and the extent of validity of the force reduction factor ( q -factor) approach for the design. The results show that displacement ductility demands in bridges designed by the q -factor method for a multisupport excitation are in good accordance with the selected value of q . The bridges designed for synchronous input and then checked for nonsynchronous motion exhibit an excess of strength in the central piers, whereas the opposite occurs for those close to the abutments, which may have displacement ductility ...

In recent years there has been renewed interest on integral abutment bridges (IABs), mainly due to their low construction and maintenance cost. Owing to the monolithic connection between deck and abutments, there is strong soil‐structure interaction between the bridge and the backfill under both thermal action and earthquake shaking. Although some of the regions where IABs are adopted qualify as highly seismic, there is limited knowledge as to their dynamic behaviour and vulnerability under strong ground shaking. To develop a better understanding on the seismic behaviour of IABs, an extensive experimental campaign involving over 75 shaking table tests and 4800 time histories of recorded data, was carried out at EQUALS Laboratory, University of Bristol, under the auspices of EU‐sponsored SERA project (Seismology and Earthquake Engineering Research Infrastructure Alliance for Europe). The tests were conducted on a 5 m long shear stack mounted on a 3 m × 3 m 6‐DOF earthquake simulator, focusing on interaction effects between a scaled bridge model, abutments, foundation piles and backfill soil. The study aims at (a) developing new scaling procedures for physical modelling of IABs, (b) investigating experimentally the potential benefits of adding compressible inclusions (CIs) between the abutment and the backfill and (c) exploring the influence of different types of connection between the abutment and the pile foundation. Results indicate that the CI reduces the accelerations on the bridge deck and the settlements in the backfill, while disconnecting piles from the cap decreases bending near the pile head.

This study presents the results of a refined numerical investigation meant at understanding the time‐dependent cyclic behavior of reinforced concrete (RC) bridge columns under chlorides‐induced corrosion. The chloride ingress in the cross‐section of the bridge column is simulated, taking into account the effects of temperature, humidity, aging, and corrosion‐induced cover cracking. Once the partial differential equations governing such multiphysics problem are solved through the finite‐element method, the loss of reinforcement steel bars cross‐section is calculated based on the estimated corrosion current density. The nonlinear cyclic response of the RC bridge column under corrosion is, thus, determined by discretizing its cross‐sections into several unidirectional fibers. In particular, the nonlinear modeling of the corroded longitudinal rebars exploits a novel proposal for the estimation of the ultimate strain in tension and also accounts for buckling under compression. A parametric numerical study is finally conducted for a real case study to unfold the role of corrosion pattern and buckling mode of the longitudinal rebars on the time variation of capacity and ductility of RC bridge columns.