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- Bond strength of textured micropiles grouted to concrete footingsPublication . Veludo, J.; Dias-da-Costa, D.; Júlio, E.N.B.S.; Pinto, P.L.In a previous research study the authors performed push-out tests with smooth micropile inserts grouted under varying confinement conditions. It was shown that: (i) failure always occurs at the steel-to-grout interface; and (ii) the connection capacity increases with the passive confinement. To increase the connection capacity, it is a common practice to weld steel rings on the surface of the micropile and execute grooves in the predrilled hole. Therefore, a new study is herein presented aiming to widen the conclusions already drawn by analysing the influence of most important parameters in the bond strength of textured micropiles grouted to concrete footings. Laboratory tests were specifically designed for assessing the effect on the connection capacity of the: (i) diameter of the predrilled hole; (ii) insert’s embedment length; (iii) active confinement of the footing; and (iv) treatment of the hole surface. Eighteen textured micropile inserts grouted in RC footings were submitted to monotonic push-out tests until failure. In brief, it can be stated that the capacity of the micropile-to-footing connection increases by increasing the insert’s embedment length and by decreasing the hole diameter. Moreover, an adequate active confinement must be provided to achieve the required capacity.
- Compressive strength of micropile-to-grout connectionsPublication . Veludo, J.; Júlio, E.N.B.S.; Dias-da-Costa, D.Strengthening foundations with micropiles is progressively being used, due to the major advantages that this technique presents. Nevertheless, the influence of some relevant parameters in the overall behavior of the retrofitted foundations has not yet been studied. Generally, micropiles are installed in holes drilled through the existing RC footing, which are then filled with grout. The efficiency of the load transfer mechanism depends on the bond strength of both the micropile-grout and the concrete-grout interfaces. This paper describes an experimental study performed to specifically study the influence of the following parameters on the bond strength between micropile-grout interface: hole diameter; embedment length of the micropile; and level of confinement of the grout mass. Thirty micropile-grout specimens were submitted to monotonic push-off tests, until failure. Bond strength was found to increase with a decrease of the hole diameter and with an increase of the confinement level. © 2011 Elsevier Ltd. All rights reserved.
- IoT in Greenhouse Supported by Climate Conditions Management PlatformPublication . Galvão, João; Neves, Filipe; Vieira, João; Rafael Simões; Ribeiro, Vânia; Costa, PauloThe system called iMeteo4all is a management platform for several physical variables, inherent to the control and management of climatic conditions inside structures, for the intensive production of plants called greenhouses and to be one contribution for agriculture 4.0. The objective of this work was to design and develop software for monitoring and managing the quality of the internal environment, through successive data collection/readings provided by a network of sensors and process automation for more efficient and sustainable agriculture. Different case studies of greenhouses whose production technologies are distinct, such as aquaponics and soil technologies were considered, in these controlled environment structures to produce plants (edible and non-edible). This platform requires an Internet address to perform the interface among a tablet, a cell phone, a computer and communication systems between a net of IoT (Internet of Things) sensors, which collect climatic variables inherent to growth and connected to several MCUs (Micro Controller Unit). Subsequently, managers and employees will be able to view and interact in real time, making more accurate decisions, depending on the climatic variations inside the greenhouse, increasing efficiency in several areas in greenhouses. It is possible to access the history of each sensor and configure automations according to the collected data. Access to data from this solution is secure through an SSL (Secure Sockets Layer) certificate applied to the public https address. If hardware failures exist, the system is prepared to be restored through regular backups in the cloud and internally, providing users with confidence and robustness in the constant use of this platform.