CiviTest
  • Vila Nova de Famalicão, Braga, Portugal
Recent publications
Coastal defence works, such as breakwaters, are structures that aim to support the action of waves and dissipate their energy. Therefore, they provide conditions for stabilizing the coast, protecting ports, beaches and other coastal infrastructures and ecosystems. Semicircular breakwaters have been applied in different locations around the world due to their aesthetic advantages and high structural performance. Marine structures are subject to hydrodynamic actions normally estimated through physical models. However, these models are complex to implement, involving high costs and long experimental procedures. Thus, alternative methodologies for studying the hydrodynamic performance of these structures are of great use. This work presents the results of the application of a computational fluid dynamics (CFD) tool to study the stability of a perforated semicircular breakwater, based on a rubble mound foundation. The model was validated against experimental results of the critical weight necessary to resist sliding, taking into account the effects of water depth and different characteristics of the waves. A comparison is made between the perforated and the non-perforated solution in terms of the breakwater’s performance to dissipate wave energy. Dissipation conditions of this energy, in the exposed face, are also evaluated in detail, in order to assess the potential of this structure as a biological refuge for marine species. Both solutions show similar performance in terms of results obtained for the wave reflectivity coefficient. The turbulence dissipation on the exposed face of the perforated breakwater is limited to a region of restricted extension around it, which is advantageous in terms of the passage of species into the breakwater.
The aim of the present work is to assess the effectiveness of an innovative strengthening technique for the rehabilitation of masonry buildings deficiently prepared to resist to loading conditions typical of seismic events. This technique is based on the application of outer layers of fibre reinforced mortar (FRM) by spray technology and it is used for increasing the load carrying capacity and deformation ability of masonry elements. For this purpose three almost real scale schist walls prototypes were strengthened and tested. The experimental program is described and the relevant results are presented and discussed. For estimating the properties of the schist walls and FRM taking into account the application conditions, the tested prototypes were simulated with a FEM-based computer program that has constitutive models for the simulation of the nonlinear behaviour of these materials. By using the derived properties, a parametric study was conducted to identify the influence of the FRM properties on the performance of the proposed strengthening system.
An innovative technique is being developed for the structural rehabilitation of Reinforced Concrete (RC) structures. In particular, the infill walls of RC framed structures are often identified as non-structural elements, but currently are considered with an important role in the structural behavior because they participate to the in-plane strength and stiffness of the frames and they can give very dangerous crashes out-of-plane. In this paper a strengthening technique aimed to repair infill walls is proposed. It is based on the application of outer thin layers of ultra-high ductile fiber reinforced mortar (UHDFRM) applied according to the shotcrete technique, including the use of embedded through section (ETS) connectors. This strengthening system can exhibit a high strength and ductile behavior, increase the load carrying capacity, energy absorption and dissipation capacities, and ultimately improve the structural response of RC structures when submitted to loading conditions typical of seismic events. An experimental program was outlined in order to assess the contribution of different types of ETS connectors on the behavior of the strengthening system. The experimental program comprised the performance of push-out tests on samples representative of the structural strengthening solution, namely low strength concrete samples. The experimental results are discussed in detail in order to highlight the effectiveness of the various types of ETS connectors tested.
In this paper, a new generation of composite sandwich slab is proposed as a solution for the rehabilitation of slabs in old masonry buildings. An innovative solution was developed during this research formed by four components: a Deflection Hardening Cement Composite (DHCC) layer on the top compression skin, a glass fiber reinforced polymer (GFRP) skin at the bottom tension surface, GFRP ribs to transfer shear from top to bottom layers, and foam core for thermal-insolation purposes. The DHCC layer contributes significantly for the load carrying and deflection capacity due to its stiffness, compressive strength and toughness, offers resistance to the occurrence of buckling phenomena in the GFRP ribs, improves the performance of this structural concept against impact and fire, and constitutes an excellent medium for the application of finishing materials, like ceramics or timber. Two different hybrid composite slabs were developed and tested, and their behavior was assessed under flexural loading. The results showed that the developed hybrid sandwich slabs accomplish all design requisites for serviceability and ultimate limit states, and assure a stiffness/dead-weight and load-capacity/dead-weight ratios much higher than conventional structural slab systems.
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Information
Address
Rua da Indústria 144, 4770-160 Jesufrei, Vila Nova de Famalicão, Braga, Portugal
Head of institution
Professor Joaquim A. O. Barros
Website
http://www.civitest.pt/en/homepage/
Phone
+351 252 315 199