Tensegrity greenhouse: An innovative covering structural system with low shading

Based on the structural principle of “Tensegrity” (tensional integrity), an innovative typology of greenhouse was developed. The principle behind the study uses structural elements of small sections (bars and cables) and employs compressed elements included in a network of tensioned elements. The innovative greenhouse structure allows covering larger spans than the most common greenhouse typologies on the market, improving the surface area usable for crops and reducing the structural sections. The present research focuses on the evaluation of the shading caused by the structural elements inside the tensegrity greenhouse, compared with the most common commercial typologies. At this aim, simulations of illuminance factor (IF) at different distance from the ground level were assessed by means of Revit, a software for building information modelling (BIM), developed by Autodesk Inc., which allows analyzing the impact of natural light and shadows on the interiors of buildings. The IF of the tensegrity greenhouse model (TGM) was compared with the one calculated for different greenhouse typologies (planar pitched roof and vaulted roof) having the same area (118.75 m2) and height of the gutter (3.5 m) placed in Rome (Italy). For all kind of greenhouses, the daily variation of the IF was evaluated in two representative days of the year: June 21 and December 21. As result, the TGM showed a value per square meter of the IF Higher than about 20% compared to traditional structures

Innovative Tensile Structures for Protected Crop Facilities

Greenhouse structures are complex buildings that must meet different needs, such as the microclimate control inside the greenhouse, the strength of structural elements, as well as the radiometric and mechanical features of roofing materials. The covering system must allow the transmission of solar radiation for crop needs and guarantee resistance performances in relation to external actions, such as wind and snow loads. Starting from the main characteristics of agricultural commercial greenhouses and tensile structures, the proposal concerns with an innovative tensile supporting structure designed for the covering of protected crop facilities. The innovative tensile structural configuration was first studied by means of the selection of the construction materials and the cross sections of the structural components and afterward calculated using the structural analysis software SOFISTIK. The load analysis on the structure was carried out in accordance with the European standards UNI-EN 13031-1: 2004 and the Italian Technical Construction Code of 2018 related to the Eurocodes. The main results concern the comparison with the current structural types of commercial greenhouses: analysis of the steel weight of the structure and improvement of the structural response to external actions of the innovative tensile structure

Enhancement of the Roman Bridge of Canosa in the Ofanto Valley Rural Landscape

The ancient Roman Bridge, 2,000 years old, is located on the old Via Traiana route, three kilometers far from the town of Canosa (Apulia Region), and for many centuries it was the connection between northern and southern part of the Apulia Region along the Adriatic coast. It has an imposing structure stonework, with a donkey back shape, built with five round arches supported by piers sustained by rostrums. During the Second World War, a concrete access way was realized in order to let the British and American army tank pass through the bridge. The “Municipal Plan of the Tratturi” qualifies the area as “sheep trails or path” that preserves the original consistency or that can be at the same renovated. Aim of the research is the requalification of the study area through analyses, plan and restructuring the ancient routes. In this study, the current status of the area is analyzed in detail and the inconsistency of the interventions is highlighted. The project proposal provides for new tourism paths equipped with cycle/pedestrian tracks and small resting and refreshment areas, intermodal exchange car parks and management structures, allowing the creation of a green tourist-cultural route

Polycarbonate laminates thermo-mechanical behaviour under different operating temperatures

This study deals with tensile tests on rigid polymeric innovative material for greenhouse covering. Specimens of polycarbonate Makrolon ® UV Climate Control blue were analyzed. Tension tests were conducted on bone-shaped samples, according to European standards, and at different temperatures from 20 °C to 80 °C on the basis of the summer temperatures registered by the greenhouses supporting metal structures in contact with the plastic covering. During tensile test the surface temperature of the specimens was measured using infrared technology. Finally, the obtained strain and temperature trend are discussed and an interpretation of the mechanical behaviour of the material is given based on a Griffith like approach

Comparative Study of Smeared Cracking Models for Concrete Structures

The article shows how the constitutive modeling of concrete has evolved since the initial attempts to characterize the medium cracked as continuous, moving from smeared cracking, damage and microplane models, until the current tendency to design different models according to a single theoretical framework. A generic formulation for smeared cracking models, including fixed and rotational models, as well as degradation in tension and in compression, is provided. Using this formulation, three models are generated by specifying the laws of degradation. A comparative study of models, based on computer simulations of a beam subjected to shear at four points, is presented. The results are compared, between themselves and with experimental results, providing a critical analysis of the models