1,720,961 research outputs found
Il viadotto di Silea in Veneto: verifica sismica secondo la normativa italiana e l’eurocodice
No full textRetrofitting of the Historic Castagnara Bridge in Padua, Italy, with Fibre Reinforced Plastic Elements
No full textMasonry arch bridges are typically historical infrastructures that were often not designed to withstand the heavy truck traffic that they are currently carrying and therefore must be replaced by modern concrete or steel bridges. Usual methods of strengthening masonry bridges are neither simple nor economical. This paper investigates whether the application of composites in the form of either a fabric wrap or laminate strips to masonry constructions, may increase the load-bearing capacity of these structures. This research project demonstrates how advanced composite materials can be used to strengthen existing masonry arch bridges in order to increase their load-baering capacity.
This paper details the methodology adopted to retrofit and repair the Castagnara masonry bridge in Padua (Italy) and the investigations related to the damage of the bridge, the retrofiting by fibre reinforced plastic (FRP) and the results of the consolidation. Retrofitting involves the insertion of a prestressed steel cable into the abutments, consolidating injections, bonding by FRP strips on the extrados of the deck and demolition and reconstruction of the reinforced concrete slab. Linear-elastic and non-linear dynamic analysis of the bridge have been performed. Detailed finite element models (FEM) and on-site dynamic acceleration measurements were used to evaluate retrofit performance. Results show that applying carbon fabric to the masonry bridges provides significant increases in bending and shear capacity.
However, a statistically significant number of masonry structures strengthened with carbon fibres need to be tested to arrive at definitive stress modification factors
Testing of "Global Young's Modulus E" on a rehabilitated masonry bell tower in Venice
No full textThis paper shows the effectiveness of the techniques chosen for the rehabilitation of the historic “Sant'Andrea” masonry bell-tower in Venice. The achieved rehabilitation projects based on the so-indenting technique consisting in removing and replacing bricks in bad conditions, and on the isolation of the bells at the belfry quote, respect all the constraints represented by the aesthetic and structural features of the building. Moreover, the experimental analyses used to define the existing state of the structure are described in detail. The tower is also an interesting case study for the validation of the proposed method to determine the Global Young's Modulus in a rehabilitated masonry bell tower. © 2017 Elsevier Lt
Retrofit of the Saint Andrea Masonry bell tower in Venice
No full textIn this paper an 1800's masonry tower is analyzed in order to assess its structural behaviour, its seismic vulnerability and to design the retrofitting. This paper details the consolidation of the masonry tower with the comparisation between the existing state and the retrofitted state. The heterogeneity of the soil has acted in a manner to determine the failures. The comparison demand versus capacity confirms the susceptibility of this type of building to extensive damage and possible collapse, which has been frequently observed. The analytical and numerical models adopted to interpret the experimental results have all confirmed that the first harmonic frequency of oscillation of the largest bell is very close to the first eigen frequency of the bell tower structure. The experimental analysis have shown that the retrofitted improved the seismic behaviour and the security level of the towe
Experimental analysis of the Saint Andrea masonry bell tower in Venice. A new method for the determination of Tower Global Young s Modulus E
No full textIn this paper an 1800's masonry tower is analyzed, in order to assess its structural behavior and the frequency of vibrations to the structure. This paper details the experimental analyses performed to define its existing state. The movement of the tower is Subject to the actions produced by the motion of the three bells and the effects of the bells are analyzed. The heterogeneity of the soil has acted in a manner to determine the failures. The comparison demand versus capacity confirms the susceptibility of this type of structure to extensive damage and possible collapse, which has been frequently observed. The dynamic behavior of the bells is investigated and the vibration frequency to the structure. The analytical and numerical models adopted to interpret the experimental results, have all confirmed that the first harmonic frequency of oscillation of the largest bell is very close to the first eigen-frequency of the bell tower. The comparison is performed between the experimental methods of investigation: by ambient noise, by the movement of the bells and by vibrations due to an instrumental hammer. It is found that the one based on the movement of bells is not available while the other two methods provided the same value. Consequently it is very probable that this value is a very accurate experimental value of the frequency.It is possible to obtain an equivalent global elastic modulus E of the tower. Such a modulus can be obtained by applying Rayleigh's method, for various E values, until the obtained analytical frequency coincides with the above-mentioned experimental accurate value.By utilizing the E modulus so determined in F.E.M. analysis of the tower a theoretical first fundamental frequencies is determined which coincides with the previous determinate experimental frequencies. This confirms that the global elastic modulus E that determined is the exact value of Young's modulus of the tower. (C) 2009 Elsevier Ltd. All rights reserved
Seismic assessment of a venetian bell tower taking into account soil-structure interaction
No full textThe paper gives a preliminary insight into the seismic vulnerability of bell towers, discussing a real case study, namely a masonry tower built in XIX century and located in the Province of Venice (Italy). Such a case study is fully investigated using different advanced FE strategies. The case study shows structural features often common in other cases, such as the foundation rotation due to soft soils, which causes the tower to lean. Both these parameters, the soil-structure interaction and the inclination, are expected to play a crucial role in the dynamic response and the lateral bearing capacity reduction. The present literature suggests different approaches to model and to account for such parameters, whereas technical codes mostly seem to propose simplified procedures that result in an underestimation of the real effect. The role of the soil is observed to be crucial in the shape and excited mass changes of the natural modes, thus implicitly modifying the seismic response. Furthermore, in general, the out-of-verticality of a tower causes the concentration of the vertical stresses and a significant capacity drop. In the present paper, different FE simulations are performed in order to investigate the actual dynamic behavior of the tower under study, to be compared with standard modeling used for bell towers
Testing of "Global Young's Modulus E" on a rehabilitated masonry bell tower in Venice
No full textThis paper shows the effectiveness of the techniques chosen for the rehabilitation of the historic “Sant'Andrea” masonry bell-tower in Venice. The achieved rehabilitation projects based on the so-indenting technique consisting in removing and replacing bricks in bad conditions, and on the isolation of the bells at the belfry quote, respect all the constraints represented by the aesthetic and structural features of the building. Moreover, the experimental analyses used to define the existing state of the structure are described in detail. The tower is also an interesting case study for the validation of the proposed method to determine the Global Young's Modulus in a rehabilitated masonry bell tower. © 2017 Elsevier Lt
Distributed strain measurements in a CFA pile using high spatial resolution fibre optic sensors
No full textStatic load tests on fully instrumented piles are a useful tool for optimizing the design of pile foundations. By measuring the change in strain along a test pile it is possible to estimate pile-soil interface properties and infer site-specific and technology-specific load-transfer curves to be adopted for design. This paper presents strain measurements obtained from a distributed sensor installed in a continuous flight auger (CFA) pile undergoing a static load test. Distributed sensing was performed using optical frequency domain reflectometry (OFDR), which provided a spatial resolution of 10 mm. The high spatial resolution allowed to highlight local defects, as those produced by undesired variations in the pile cross-section area that can lead to erroneous data analysis if not fully understood. The paper also presents an approach for the derivation of load-transfer curves from continuous strain data
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