574 research outputs found
Calcestruzzi speciali per ridurre la deformabilità di elementi inflessi in cemento armato
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Assessment of RC Bridges integrity by means of low-cost investigations
No full textInfrastructure aging is an important problem nowadays, in particular for countries like Italy in which the main motorways were built 50 years ago. Huge budgets are necessary to keep infrastructure and bridges in service. In addition, the lack of a proper and timely maintenance, entails an increase of the deterioration and therefore higher costs of repair.
Thus, the need of methods capable of assessing the reliability of the infrastructure in the frame of Bridge Management System (BMS), is patent. The aim of this work is to provide a robust decision-support tool for the analysis of the data collected with field inspection. The innovative aspect of the proposal is the introduction of two factors which take into account the location of the damage, and the mechanical characterization of the material in the definition of a Condition Rating Number (CRN).
The analysis of an existing Reinforced Concrete (RC) bridge network is presented in order to show the accuracy of this new method
La casa del balilla di Arborea. Storia della costruzione e indagini sul manufatto
No full text"The “Casa del balilla” (house of the child) was designed in 1934 by G. B. Ceas. It was built in Mussolinia, Sardinia, (today named Arborea) and it represents an important example of reinforced concrete architecture. It includes a gym, a sports field and an outdoor pool. The pool is framed by four reinforced concrete lattice beams characterized by an upper curved profile. Their span is 21 meters and what is very interesting is the metallic rollers that realize the simply supported boundary conditions. In an intermediate position there are four pillars, coated with staggered bricks. They have no structural role and present deep vertical cracks, for their entire height on all sides. In this paper, we report the historical and experimental, investigation process, which led to the restoration of the whole building.
Case study of a reinforced concrete industrial warehouse exposed to fire: Post fire investigation and retrofitting
No full textThis paper reports on the post fire investigation and on the retrofitting of a real Reinforced Concrete (RC) industrial warehouse damaged by fire.
A complete set of assessment techniques has been merged to obtain a modern integrated approach. The main aim of this method was to evaluate the structural residual safety and consequently the maximum temperature distribution. The information collected was of paramount relevance to design the retrofitting of the structure. It was developed using unidirectional sheet made of ultra- high-strength galvanized steel micro-cords fixed to a fibreglass micromesh. In this way the refurbishment was convenient and efficient. The design methods and many technical details are presented in this paper in order to show what can be considered a state of-the-art approach for post fire structural assessment
Low cost condition assessment method for existing RC bridges
No full textAging infrastructures represent a current engineering challenge. Huge budgets are necessary to keep their functionality and the lack of a proper and timely maintenance entails an increasing deterioration and therefore higher repair costs. Therefore, assessing the reliability of infrastructures becomes mandatory, with particular attention to the ones still in service even when their life limit has exceeded. This paper aims to propose a new, fast and low cost method of condition rating for reinforced concrete bridges. This is based on visual inspection and non-destructive testing. The main innovation is represented by the parameters taking into account the mechanical degradation of materials and the damage location at the structural sub-component level. The analysis of some benchmark examples and the comparison with other methods are presented in order to assess the reliability of the new proposal
Structural and thermal retrofitting of masonry walls: An integrated cost-analysis approach for the Italian context
No full textConstructions ageing is a relevant problem in developed country like Italy. In particular, in case of existing masonry buildings, retrofitting interventions aimed at improving structural and thermal performances represents an obvious need. At the same time, sustainability awareness of buildings life-cycle has grown in the last years. Consequently, the whole life-cycle of constructions should be analyzed and assessed during the design of retrofitting interventions. In order to take into account these aspects new design and planning methods are necessary. This paper presents an integrated approach to evaluate structural and thermal retrofitting strategies for masonry walls. Economic and ecological costs of each examined retrofitting solution are compared, taking into account thermal and seismic capacity demand of the construction site. Given the economic cost, a set of retrofitting solutions for masonry panels have been mapped with a couple of parameters (structural strength Vs thermal insulation). An analogous mapping, considering the ecological cost due to equivalent CO2 production, have been performed. A methodology to find the best solution among a set of retrofitting solutions is presented, depending on the location of the building and its seismic and thermal characteristics. Examples, based on six retrofitting techniques located in four different sites in Italy, are analyzed to explain the effectiveness and the feasibility of the proposed method. The comparison between ecological and economical cost allowed to highlight the characteristics of the different interventions. Thermal performance proved to be more important in cold weather conditions while structural retrofitting is preferable in high seismic risk areas
Estensive Restoration of the Colombo Bridge (Sardinia)
No full textThe Colombo bridge was built across the Mannu river in Sardinia, (Italy) between 1966-68. This bridge consists of 15 spans, each 15 m in length, 12 of these span the Mannu river and 3 span a railway.
The bridge deck is constructed out of precast pretensioned concrete I-beams, 0.80 m spacing with overlaid precast parts. It is based on a continuous pier cap, which is supported by 4 piers, each made of 2 circular columns. Continuous foundation beams distribute loads down to 0.60 m reinforced concrete piles.
In 1992 serious static damage was identified and the 2 circular columns were connected together, thus becoming a unique structure.
In 2002 due to increased heavy traffic, serious static risk and serious deterioration of the building materials, a total renovation of the structure including all structural aspects, from bridge deck to foundation piles was undertaken.
Core samples of the concrete from the piers and foundation were examined and reinforcing rebars mapped, direct load testing on the foundation piles were also carried out.
The renovation project, the extensive non destructive experimental tests and the testing of the load carrying capacity of the piles are disclosed in the following report
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