Mauro Sassu

Collapse of corrugated metal culvert in Northern Sardinia: analysis and numerical simulations

The paper illustrates the possible causes of collapse of a Corrugated Metal Culvert (CMC), occurred in Northern Sardinia after an extreme rainfall event in 2013. The possible causes of collapse are related to the conditions before and during the rainfall. Erosion and corrosion phenomena, which caused material decay and an improper water flow, have been discussed. Numerical analyses were performed to identify buckling multipliers with a finite element model simulating the effect of combined erosion and corrosion. The analysis showed a greater sensitivity in terms of buckling resistance when the soil erosion is concentrated in the lower portion of the culvert rather than in the lateral one.

Failure scenarios of small bridges in case of extreme rainstorms

Abstract This contribution comes from the investigations carried out on recent flooding events occurred in Italian suburban areas. Those events, regarding minor roads, cause unexpected failure modes of existing bridges with reduced span (less than 10 m), whose construction and maintenance are not properly covered by standards. Three failure scenarios are here considered: the dragging effect on vehicles when they are crossing bridges (A), the erosion effect due to the overtopping of the bridge (B), and the erosion and the floating effect caused by upward buoyant force from Archimedes’ principle on the bridge slab (C). The described mechanisms of failure are paradigmatic to identify not only the structural collapses but also the service failure. In this sense, the ‘resilience’ of the small bridge is defined, in view to propose technical indications for maintenance and consolidation activities.

Experimental Analyses and Numerical Models of CLT Shear Walls under Cyclic Loading

This paper reports the results of an experimental campaign performed at the University of Tokyo on cross-laminated timber (CLT) panels subjected to lateral loads. Analytical and numerical interpretations are provided as well, comparing the experimental analysis results with two methods: firstly, an analytical method to preliminarily evaluate the ultimate strength of the four panels, based on the geometrical dimensions of the openings and of the panel; secondly, a finite element model has been developed in order to provide some guidelines for calculating the stiffness and elastic behaviour of CLT panels subjected to lateral loads. The experimental tests showed that the CLT panels are as more brittle and stiffer as more the difference between the total panel area and the fenestrated area is high. The presence of large openings determined stress concentration at the corners where failure occurred for the attainment of the maximum tension strength in the inner layer. The proposed analytical formulation was shown to fairly closely predict the ultimate strength of panels with same geometry, characteristics and boundary condition, allowing preliminary information of this relevant parameter.

Rocking and kinematic analysis of two masonry church façades

The authors wish to thank Ing. Luciano Bellesia for his helpful cooperation. The activity is cosponsored by Consortium RELUIS – Masonry 2014.