Lorenzo Miccoli

Long life monitoring of historical monuments via Wireless Sensors Network

The permanent monitoring of structural behavior of monuments is a crucial target in the framework of cultural heritage preservation. The paper deals with the monitoring and static risk assessment using the technique of dynamic parameter measurement in a broad Wireless Sensors Network (WSN) system. The historical buildings exposed to the traffic vibration, which can induce stresses inside the material, as well as small seismic actions, are vulnerable. Then a permanent monitoring of the micro-shocks/vibrations is suggested to be applied to the most vulnerable monuments. The use of a WSN requires to provide a robust infrastructure to support the data collecting and decision making before, during, and after a crisis event. When a crisis occurs, through the use of such information collection methods an appropriate plan is dynamically instantiated with the specific details of the crisis.

Monitoring and vibration risk assessment in cultural heritage via Wireless Sensors Network

The monitoring of monuments structural behavior is a subject of crucial importance for cultural heritage preservation. Monitoring and vibration risk assessment in a broad WSN (Wireless Sensors Network) system allows to provide a robust infrastructure to support the data gathering and decision making before, during, and after a crisis event.

Dynamic characterisation and seismic assessment of medieval masonry towers

The paper investigates the dynamic characterisation, the numerical model tuning and the seismic risk assessment of two monumental masonry towers located in Italy: the Capua Cathedral bell tower and the Aversa Cathedral bell tower. Full-scale ambient vibration tests under environmental loads are performed. The modal identification is carried out using techniques of modal extraction in the frequency domain. The refined 3D finite element model (FEM) is calibrated using the in situ investigation survey. The FEM tuning is carried out by varying the mechanical parameters and accounting for the restraint offered by the neighbouring buildings and the role of soil–structure interaction. The assessment of the seismic performance of the bell towers is carried out through a nonlinear static procedure based on the multi-modal pushover analysis and the capacity spectrum method. Through the discussion of the case studies, the paper shows that the modal identification is a reliable technique that can be used in situ for assessing the dynamic behaviour of monumental buildings. By utilising the tuned FEM of the towers, the theoretical fundamental frequencies are determined, which coincide with the previously determined experimental frequencies. The results from seismic performance assessment through a pushover analysis confirm that the masonry towers in this study are particularly vulnerable to strong damage even when subjected to seismic events of moderate intensity.

Numerical modelling of UHPC and TRC sandwich elements for building envelopes

In this paper a modelling approach is presented to reproduce the mechanical behaviour of sandwich panels via finite element analysis. Two types of panels were investigated in this scope of work. The first sandwich element was a textile reinforced concrete (TRC) panel with cellular lightweight concrete insulation and the second configuration was an ultra-high performances concrete (UHPC) panel with aerated autoclaved concrete insulation. The goal was to obtain a reliable numerical strategy that represents a reasonable compromise in terms of sufficient accuracy of the element characteristics and the computational costs. The results show the possibility of describing the composite action in a full sandwich panel. The achieved modelling approach will later be used for the optimization of TRC and UHPC panels in terms of minimizing the thickness, identifying the number and location of connectors, as well as evaluating varying anchorage systems.

Experimental investigations on the initial shear strength of masonry with earth mortars

In this paper, a comparative study on the initial shear strength of masonry with earth mortars is presented. Triplet tests were carried out to characterise the shear bond strength of five different types of earth mortar, three purely mineral and two with vegetable additives (wood and straw chaff), using calcium silicate blocks. In spite of their lower bulk densities, mortars with chaffs reached a value of compressive strength comparable to the values shown by the purely mineral mortars. The characteristic initial shear strengths of all the tested earth mortars were between two and five times higher than the minimum values for initial shear strengths required by standards. To assess the influence of blocks pre-wetting, a comparison between calcium silicate blocks and earth blocks was performed to evaluate the results obtained from the standard test procedure compared to the more common practice of using earth mortars in combination with earthen blocks.

A collaborative engineering and archaeology project to investigate decay in historic rammed earth structures : the case of the medieval preceptory in Ambel.

ABSTRACT This study assesses the structural vulnerability of part of a later medieval earthen building at Ambel (near Zaragoza, Spain), once a preceptory or monastic house belonging to the Military Orders. An inspection of its morphology and materials coupled with the results of an extensive campaign of static monitoring reveals marked structural inhomogeneities, the product of more than a thousand years of construction, failure, and repair from the 10th century to the present day. Building materials are inappropriately juxtaposed, there are discontinuities between construction phases and fundamental concerns remain over the long-term stability of the structure. The current condition of the structure is mainly influenced by structural discontinuities introduced at the time of construction, the unintended consequences of repair and modification and the material decay that has affected the base of the rammed earth walls. The overall findings of the static monitoring show that there is no related damage, variations in crack widths are related to the building seasonal cycle. While static analysis is an essential prerequisite before a suitable maintenance program can be fully defined, this study argues that no evaluation of the structural behavior of any historic building can afford to ignore its archaeological “biography” of modification and repair.

In-plane behaviour of earthen materials: a numerical comparison between adobe masonry, rammed earth and cob

The paper presents a comparison between different numerical modelling ap-proaches aiming to simulate the in-plain behaviour of three types of earthen materials, name-ly adobe masonry, rammed earth and cob. For this purpose, uniaxial and diagonal compression tests were carried out, which allowed determining important mechanical param-eters, such as compressive strength, Young’s modulus, Poisson’s ratio, shear strength and shear modulus. Furthermore, the tests allowed assessing the level of non-linear behaviour of the respective stress–strain relationships as well as the failure modes. The experimental results were then used for the calibration of numerical models (based on the finite element method) for simulating the non-linear behaviour of the earth materials under in-plane shear loading. Both macro- and micro-modelling approaches were considered for this purpose. The procedures adopted for model calibration established the reliability of various modelling strategies for the different loading conditions. The simplified approach based on macro-modelling shows a satisfactory accuracy and low computational costs. The results reproduc-ing the uniaxial compression are in good correspondence with the post-elastic behaviour ob-served in the experimental campaign. The micro-modelling approach adopted to reproduce the shear behaviour, even with higher computational cost, represents a suitable tool to pre-dict the adobe masonry and rammed earth collapse mechanisms

In-plane shear behaviour of earthen materials panels strengthened with polyester fabric strips

An experimental investigation was carried out to study the in-plane shear behaviour of earthen material panels strengthened with polyester fabric strips. Strengthened panels were developed to exploit the strength potential of earthen materials and to solve its lack of tensile strength, significantly improving not only strength but also ductility. Three earthen materials were considered: cob, earth block masonry (EBM) and rammed earth (RE). As first approach the strengthening configuration, based on different adhesive materials, was tested only for cob panels. As part of the study the results of a big testing campaign of unstrengthened Panels were considered. Seven strengthened panels were tested in diagonal compression/shear.A unique reinforcement orientation was used. The results of these tests are presented in this paper, and include the load-displacement behaviours, crack patterns, failure modes. The results showed that the reinforcement was the most effective in EBM panels, with increase in strength and ductility observed. In RE and cob panels the reinforcement did not likely contribute significantly to the shear resistance, due to a lack of embedment length of the strips. Instead, in EBM it was likely that the vertical reinforcement acted in tension to restrain shear induced dilation and to restrain sliding.

Permanent structural health monitoring via remote control

The permanent monitoring of structural health of buildings and bridges is a critical target in the framework of diagnosis and alerting in structural engineering. The paper deals with the monitoring of dynamic and static risk assessment using remote control technologies as technique of dynamic parameter measurement in a wireless sensors network system. The structures, due to the aging decay of the material as well as to the exposition to the traffic vibration, or due to the increasing load, can show stresses inside the material, as well as damage which if accumulated can lead even to partial or total collapse. Then, a permanent monitoring of the micro-shocks/vibrations during the life of the structure is suggested to be applied to the most sensitive and important structures. The use of remote control technologies makes feasible to provide a robust infrastructure to support the data collection and the decision making before, during, and after emergencies.Fatigue problem in steel bridge has been investigated for a long time by structural engineers. Various surface treatments such as shot peening, air-hammer peening, grinding, polishing, can improve the fatigue life of steel component. In recent years, Fluid Bed Peening (FBP) methods are investigated at the university of Rome “Tor Vergata”. Fluid Bed Peening (FBP) as a technique of surface treatments can dramatically improve the fatigue behaviour, and demand less operational parameters. Material tests done by M. Barletta et al. showed FBP can improve the roughness of material surface significantly. The measurements showed the surface properties were significantly improved, and were supposed to increase the fatigue resistance. In this paper, the fatigue behavior of specimens treated by FBP was investigated. The specimens were divided into four different groups: simple (group A), simple and treated by FBP (group B), notched (group C), notched and treated by FBP (group D), and were tested under cyclic constant-amplitude loading. Based on the tests, this paper focused on the improvement effect to the fatigue behavior of the specimens, and also the surface properties were discussed.