Development of Dynamic Laboratory Platform for Earthquake Engineering Courses

Small-scale shaking table platforms are usually used in seismic engineering courses to study the structural dynamic behavior of small scale specimens and investigate innovative solutions, such as active and passive control systems. Furthermore, they are also useful to actively involve students in learning programs in higher education. This paper illustrates the development and the teaching effectiveness of a multimodular unidirectional platform to be used by students during dynamic and seismic courses within the Shaking Table Educational Program at the Politecnico di Torino. A unique feature of this platform is that the system was entirely developed by undergraduate students. The project was intended to create a shaking table for earthquake simulation that can measure the structural response using sensors located on a specimen, such as a building, a bridge, or any other type of reduced-scale system. Different types of dynamic tests can be reproduced, such as hybrid simulations and pseudodynamic tests. A survey demonstrates the effectiveness of the laboratory experience during seismic engineering courses to improve student learning capabilities through a teaching activity that involves both theoretical and hands-on experience. Currently, the platform has been extended to accommodate bidirectional shaking table tests with the inclusion of augmented reality tools that allow exploring the response of human behavior during a pedestrian evacuation

VULNERABILITY OF ART WORKS TO BLAST HAZARD: THE FOUNTAIN OF NEPTUNE IN FLORENCE

Conservation and protection of art works is a primary goal of each community, since arti-facts represent a fundamental cultural and economic asset. In most cases, art goods are ex-hibited in Museums, which are appointed for their protection. Some of them, however, are exhibited outdoor, since they are conceived and made to enrich the public areas. In these cas-es, the art goods result to be even more vulnerable, since they are subjected both to natural hazard (i.e. earthquakes and floods) and to vandalic attacks. Art works have an intrinsic vul-nerability, due to their irregular shape, slenderness, fragility and to their oldness. This paper is focused on the dynamic response of statues to blast explosion; a valuable case-study, i.e. the Fountain of Neptune, located in “Piazza della Signoria”, in Florence. The Fountain of Neptune is a marble and bronze opus made by Bartolomeo Ammannati between 1560 and 1565. The main character of the Fountain, Neptune, is a marble statue 5.7 meters tall, with a weight equal to 11.5 ton. A preliminary laser scanner survey has been made to achieve the geometrical representation of the statue. The geometrical model has been arranged, in order to be used for structural analyses. A numerical analysis has been performed to find the dy-namic response of the statue to the loading resulting from a blast explosion. Such response has been found by assuming the explosion of assigned amounts of TNT. Some different cases have been considered, and a limit loading condition has been found for the blast, as a func-tion of its amount

Disproportionate collapse of a cable-stayed bridge

The disproportionate collapse of an existing cable-stayed bridge was investigated at the numerical level by employing a validated model from the literature and the applied-element method. An earthquake input was used for the numerical simulations and applied at increasing intensity to assess the bridge response. The role of redundancy in the bridge structural scheme was proved to be a strategic measure for avoiding disproportionate collapse and improving robustness. Therefore, an alternative configuration of the structural scheme was assessed as a possible countermeasure to improve the response of the cable-stayed bridge by providing different loading paths against disproportionate collapse. New redundancy indices that account for the system reserve resources are also introduced

Integrating a Human Behavior Model within an Agent-Based Approach for Blasting Evacuation

Several studies on Emergency Management are available in the literature, but most of them do not consider how the human behavior during an emergency can affect the evacuation process. Therefore, the novel contribution of this article is the implementation of an agent‐based model to describe the evacuation, due to a blast in a public area, integrated with a human behavior analytical model. Each agent has its own behavior that is described in a layered framework. The first layer simulates the “agent's features” function. Then, an “individual module” describes dynamically the emotional aspects using (i) the Decision Field Theory, (ii) a stationary stochastic model, and (iii) the results coming from a questionnaire. An agent‐based model with integrated human behavior is proposed to test critical infrastructures in emergency conditions without performing full scale evacuation tests. Analyses could be performed both in real time with a hazard scenario and at the design level to predict the system response to identify the optimal configuration. Therefore, the development of the proposed methodology could support both designers and policy makers in the decision‐making process

Hybrid Strategy to Achieve 3D Base Isolation of Structures

Some aspects, related to the 3D base isolation of structures to control the effects of both the horizontal and vertical components of ground motion, are presented in this paper. A massive structure (a Nuclear Power Plant building) equipped with a traditional horizontal base isolation system is numerically studied. The base isolation system uses rubber bearings (low and high damping) coupled with a tuned mass damper (TMD) in the vertical direction. Possible positive and negative aspects from the implementation of the proposed hybrid strategy are investigated. Numerical analyses show that the presence of the TMD mitigate the vertical effects of the three-dimensional ground motion coupled with the elastomeric bearings, reducing both the vertical and the horizontal absolute acceleration in the superstructure under certain conditions. Vertical acceleration in the superstructure appears related to the horizontal motion, due to the building’s centroid position that induces rocking

Bond deterioration effects on corroded RC bridge pier in seismic zone

The effects of corrosion focusing on the consequences of bond strength deterioration for a reinforced concrete bridge pier in a seismic affected area are examined in this research. A bond degradation model based on the local bond stress-slip model presented in FIB Model Code 2010 is chosen. A motorway overpass object of a previous study, which considered the rebars cross-section reduction effect only, has been selected to assess the seismic capacity of the corroded pier in the time domain when bond degradation due to corrosion is also taken into account. The modification of strength capacity and ductility of the structural element is analyzed and the effect of corrosion during the whole service life of the structure is obtained. It is concluded that the effect of bond degradation is more critical for the safety of the pier than the effect of rebars cross-section loss.Peer ReviewedPostprint (published version

MONTE CARLO APPROACH TO MODEL THE PROGRESSIVE FAILURE OF WATER DISTRIBUTION NETWORKS: APPLICATION TO A VIRTUAL CITY

The effects of the rapid urbanization and new hazards related to climate change are becoming extremely complex and unpredictable. Communities are thus seeking to improve their recovery capacity after catastrophic events through management and adaptation strategies. Generally, existing infrastructures have been built before the preparation of the seismic design guidelines, yielding to possible insufficient responses when subjected to earthquakes. Furthermore, interdependencies between different critical infrastructures is also becoming of paramount importance for improving community resilience. This paper focuses on the water distribution network as one of the most essential lifelines. The water distribution network is modeled using a specific software integrated by a mathematical toolbox. An earthquake scenario is applied to the water network and the related damages are determined by using fragility functions. The failure of the system occurs when the water flow and the water pressure go below a certain threshold. The resilience of the network is then evaluated using two indexes: (i) the number of users without water and (ii) the drop in the total water supply