1,720,963 research outputs found
Case study on seismic retrofit and cost assessment for a school building
No full textIn different high seismic regions around the world, many non-ductile existing reinforced concrete frame buildings, built without adequate seismic detailing requirements, have been damaged or collapsed after past earthquakes. The assessment and the retrofit of these non-ductile concrete structures is crucial theme of research for all the scientific community of engineers. In particular, a careful assessment of the existing building is fundamental for understanding the failure mechanisms that govern the collapse of the structure or the achievement of the recommended limit states. Based on the seismic assessment, the best retrofit strategy can be designed and applied to the structure. A school building located in Avellino province (Italy) is the case study. The analysis of seismic vulnerability carried out on the mentioned building has highlighted deficiencies in both static and seismic load conditions. The retrofit of the building has been designed based on different retrofit options in order to show the real retrofit design developed from the engineers to achieve the seismic safety of the building. The retrofit costs associated to structural operations are calculated for each case and have been summed up to the costs of the in situ tests. The paper shows a real retrofit design case study in which the best solution is chosen based on the results in terms of structural performance and cost among the different retrofit options
An innovative school building design in the town of montemiletto
No full textBackground: This paper presents an innovative design for a school building, awarded in the concourse “Scuole innovative”, published by the italian Ministry of Education, University and Research. The new school building is located in a newly built urban area of Montemiletto (Avellino, Italy), at the southeast of the Leonessa castle and the ancient nucleus of the town. The Comprehensive Institute that includes a kindergarten, a primary school and a secondary school, is proposed as a Civic Center, an “urban place”, characterized by new spaces of relationship and aggregation. Objective: The main idea of the project design is the creation of an innovative school with respect to the architectural, structural and plant system aspects and to the energetic efficiency and characterized by the presence of new environments of learning and openness to the territory. Materials and Methods: The project proposals can be summarized in the different points: a) unit of the morphological-settlement solution and the articulation of the Civic Center, to be identified as new reference point in the city; b) adherence of the characters of the school to the landscape and visual connection with the castle; c) urban and architectural role of the system of the paths and connections, which surround and enter in the intervention area; d) extension and permeation between the natural and artificial environments assigning to the roof the task of increasing open spaces; e) accentuation of the public and multi-functional character of the different spaces, so that the school can be a place for meeting and comparison, in which it is possible to test new ways of teaching; f) use of different types of green open spaces as gardens, flowerbeds, educational vegetable gardens that change with the seasons, sporting fields, cycle-forgave routes among the green. Moreover, with respect to the structural aspects, seismic isolation at the basis of the building is proposed. This paper focuses mainly on the aspects related to energy and environmental sustainability and life cycle cost with reference to the case study design. The goal is to reduce the impact on the ecosystem, trying to make the school building organic to the existing environment. The containment of energy consumption for the air conditioning of the rooms is done through the isolation of the massive walls of the façade, covered with local stone (Irpinia breccia) and polycarbonate. Water-saving is obtained by reusing rainwater for the irrigation of vegetable gardens, vegetation and sanitary use. Results and Conclusion: The use of recycled materials and components is proposed: the Irpinia breccia covering the façade and, with different grain sizes, the external roofing and flooring; the polycarbonate; the polyester insulation; the outdoor furniture in recycled wood. In addition, dry reinforced concrete construction technologies are chosen. Definitively, the main concept is to have “a school in the park”
Non-destructive tests on carpentry steels
No full textBackground: Industrial archaeology represents a modern branch of urbanism and architecture that studies, applying an interdisciplinary method, all the evidence inherent the process of industrialization from its origins to the actuality. Aim: Looking at the cities of our epoch, more and more are the testimonies of these historical artefacts, which in fact represent our cultural identity and are often intended to be recovered and converted into modern destinations of use. Methods: If the identification of constructive schemes is based on direct essays and surveys, the definition of material properties requires material testing and investigation. For metal structures, the standards involve destructive investigations only, with a sampling of specimens, which often conflict with the protection requirements of the artefact. This leads to the need to refine and make reliable non-destructive investigations using the Leeb method, by means of portable micro-durometers, for in-situ characterization of carpentry steels, so to suggest new regulatory guidelines for existing structures surveys. Results: In the paper, the classification of carpentry steels based on non-destructive hardness test was illustrated and discussed. Firstly, for the evaluation of the resistance class of a structural steel, it was recorded that the execution of tests required a careful cleaning of the surface of samples. Subsequently, analyzing the data obtained from the experimentation, it was clear that the best methodology of data conversion from micro-hardness (Leeb method) tests for the determination of the steel class was given by tables and formulations of the ASTM standard. In the case of a few values to be converted, the most effective method was the manual use of the tables, with an average error of 0.10%. Conclusion: In conclusion, it should be remarked that differently from the reinforced concrete structures, where the non-destructive tests are allowed by the current Italian technical code on, for metallic structures only, destructive tests are permitted, so that the use of non-destructive ones should be encouraged, especially when interventions on cultural heritage constructions are of concern
Laboratory tests on hydraulic lime mortar reinforced with jute fibres
Full text linkBackground: Considering the high seismic vulnerability of masonry buildings located in the Italian territory, the implementation of seismic retrofit programs is strongly needed.. With consideration for sustainable interventions, it is evident that the retrofit techniques to protect the historical heritage should be carried out with innovative green compound materials, such as mortars reinforced with natural fibres. Objective: In the current paper, laboratory tests on lime mortars strengthened with raw jute fibres have been performed. Methods: The workability of the fibre-reinforced mixture has been assessed through shaking table tests, and the mechanical resistances of standard specimens have been evaluated by bending and compression tests. Results: Considering the hygroscopic nature of jute, it has been identified that the optimal water/lime ratio and the maximum water percentage are absorbed by jute fibres. From the results, how the spreading of the mixture, which is indicative of the mortar consistency, changes with the water/lime ratio, has been evaluated. From bending tests, the effective behaviour of fibres, which provide a stitching effect of the failure crack in the investigated fibre-reinforced lime mortars, has been observed. Conclusion: Finally, the results of compression tests have shown that the examined fibre-reinforced mortars can be effectively used as building products according to the actual Italian technical code NTC 2018
Experimentation on lime mortars reinforced with jute fibres: Mixture workability and mechanical strengths
No full textGiven the high number of masonry buildings on the Italian territory, which was scenario of numerous devastating earthquakes, it is clear the importance of restoration programs. Thanks to a renewed technique sensitivity towards sustainable interventions, it is evident that the recovery techniques to protect the historical heritage should be carried out with innovative green compound materials, such as mortars reinforced with natural fibres. In the current paper laboratory tests on lime mortars strengthened with raw jute fibres have been performed. Workability of the fibre-reinforced mixture has been assessed through shaking table tests and the mechanical resistances of standard specimens has been evaluated by bending and compression tests. Given the hygroscopic nature of jute, it has been identified the optimal water/lime ratio and the maximum water percentage absorbed by jute fibres. From analysis results it has been evaluated how the spreading of the mixture, which is indicative of the mortar consistency, changes with the water/lime ratio. From bending tests, it has been noticed an effective behaviour of fibres, which provide a cracks seam effect able to make more ductile the behaviour of investigated fibre-reinforced lime mortars. Finally, the results of compression tests have shown that the examined fibre-reinforced mortars can be effectively used as building products according to the actual Italian technical code NTC 2018
Innovative and traditional seismic retrofitting techniques of an existing RC school building: life cycle assessment and performance ranking through the TOPSIS method
No full textHow does the knowledge level affect the seismic retrofit cost? The case study of a RC building
No full textThe retrofit of existing structures in high seismic zones is a crucial issue in the earthquake engineering field. The interest of the research community is particularly high for the structures that do not respect current seismic codes and present structural deficiencies such as poor detailing and lack of capacity design provisions. A reinforced concrete (RC) school building is used as case study to show the influence of different knowledge levels on the seismic retrofitting cost assessment. The safety assessment of the case study building highlights deficiencies under both vertical and seismic loads. By considering all the possible knowledge levels defined by the Italian such as by the European codes in order to derive the mechanical properties of the school building constitutive materials, the retrofit operations are designed to achieve different seismic safety thresholds. The retrofit structural costs are calculated and summed up to the costs for in-situ in tests. The paper shows how for the case study building the major costs spent for a large number of in-situ tests allows to save a consistent amount of money for retrofit operations. The hypothesis of demolition and reconstruction of the building is also compared in terms of costs with all the analyzed retrofit options
Probabilistic seismic and fire assessment of an existing reinforced concrete building and retrofit design
No full textIn this paper, a probability-based procedure to evaluate the performance of existing RC structures exposed to seismic and fire actions is presented. The procedure is demonstrated with reference to an existing old school building, located in Italy. The vulnerability assessment of the building highlights deficiencies under both static and seismic loads. Retrofit operations are designed to achieve the seismic safety. The idea of the work consists in assessing the performance of the existing and retrofitted building in terms of both the seismic and fire resistance. The seismic retrofit and fire resistance upgrading follow different paths, depending on the specific configuration of the building. A good seismic retrofit does not entail an improving of the fire resistance and vice versa. The goal of the current work is to study the variation of response due to the uncertainties considered in records/fire curves selection and to carry out the assessment of the studied RC structure by obtaining fragility curves under the effect of different records/temperature. The results show the fragility curves before and after retrofit operations and both in terms of seismic performance and fire resistance performance, measuring the percent improving for the different limit states
Experimental shear tests on tuff blocks triplets with hemp fibres reinforced lime mortar
No full textThis paper deals with experimental shear tests carried out on triplet samples made of tuff masonry blocks joined by lime mortars without and with hemp fibres. The experimental campaign has been performed at the laboratory of the Architecture Faculty of the University of Naples "Federico II". Three samples manufactured with hemp fibres, having a percentage of 1% with respect to the mortar weight, have been tested and their behaviour has been compared to that of the triplet made of the simple lime mortars linking tuff blocks. The comparison has been done in terms of both force-displacement and shear stress-deformation angle curves. In addition, the failure modes of fibre-reinforced mortar specimens have been individuated. The performance increase deriving from the use of hemp fibres in lime mortar has been evaluated through the increment of shear stress (force), drift angle (displacement) and shear modulus. The achieved results have proved the effectiveness of hemp fibres in manufacturing reinforced lime mortars able to join together top sustainable features with high mechanical characteristi
- …
