http://repositorio.lnec.pt:8080/jspui/handle/123456789/35 DE Sun, 17 May 2026 23:32:15 GMT 2026-05-17T23:32:15Z http://repositorio.lnec.pt:8080/jspui/handle/123456789/1019506 Title: Aderência de varões de aço para betão armado utilizados em Portugal. Avaliação estatística de um novo parâmetro que caracteriza o perfil nervurado Authors: Louro, A. S.; Filipe, J. Abstract: Diversos fabricantes têm vindo a implementar alterações na superfície dos varões de aço para betão armado que impactam com a aderência varão-betão. As versões recentes dos projetos de norma destes produtos introduziram um novo parâmetro de controlo da geometria da superfície nervurada dos varões, paralelamente ao controlo da área relativa das nervuras transversais (fR), que consiste na relação entre a largura da crista das nervuras transversais a meio do seu comprimento (bR) e o afastamento das nervuras transversais (c). Este artigo apresenta os resultados de um estudo estatístico sobre os valores de bR/c, obtidos pelo LNEC nos últimos anos centrando--se no tipo de perfil nervurado. Sat, 01 Mar 2025 00:00:00 GMT http://repositorio.lnec.pt:8080/jspui/handle/123456789/1019506 2025-03-01T00:00:00Z http://repositorio.lnec.pt:8080/jspui/handle/123456789/1019504 Title: Impact of geometrical and environmental parameters on wind action in telecommunication monopoles Authors: Filipe, J.; Travanca, R.; Baptista, A. M.; Pipa, M. Abstract: Este artigo apresenta e discute os resultados obtidos num estudo paramétrico para quantificar a influência relativa dos parâmetros mais importantes utilizados para a definição da ação do vento em monopolos para telecomunicações, como a localização da estrutura e as características geométricas do fuste, assim como a existência de equipamentos auxiliares montados na estrutura, i.e. antenas, interfaces de antenas, escadas e/ou caminhos de cabos. Sat, 01 Mar 2025 00:00:00 GMT http://repositorio.lnec.pt:8080/jspui/handle/123456789/1019504 2025-03-01T00:00:00Z http://repositorio.lnec.pt:8080/jspui/handle/123456789/1019475 Title: 3D Shaking Table Tests Of A Full Scale 2-Storey Building With Fiber-Reinforced Elastomeric Isolators Authors: Losanno, D.; Prakash, S.; Medaglia, P.; Parisi, F.; Konstantinidis, D.; Tubaldi, E.; Ahmadi, H.; Strauss, A.; De Domenico, D.; Vamvatsikos, D.; Lachanas, C.; Vassiliou, M.; Ribeiro, F.; Correia, A.A. Editors: Gerard J. O’Reilly; Gian Michele Calvi Abstract: During the last two decades fiber-reinforced elastomeric isolators (FREIs) emerged as a promising option to reduce both the cost and weight of rubber bearings. The project ERIES-FREISUST (Fiber-Reinforced Elas-tomeric Isolators for seismic resilient structures with SUSTainable Solu-tions) aims to demonstrate the reliability of FREIs in limiting damage to structural and nonstructural components and contents. Two FREI systems were designed for a full-scale 2-story reinforced concrete (RC) infilled frame, differing in standardization and cost levels, namely a Virgin-rubber Carbon-fiber FREI (VC-FREI) and a Reclaimed-rubber Polyester-fiber FREI (RP-FREI). These isolation systems were installed in unbonded con-figuration at the base of the building and tested at the ST3D shaking table facility of Laboratorio Nacional de Engenharia Civil (LNEC), Lisbon, Por-tugal. The novel base-isolation systems demonstrated lateral stability and re-centering capability, as well as adequate vertical stiffness and load-bearing capacity under different ground motions. RP-FREIs were designed and tested up to a design displacement of 105mm corresponding to 150% shear strain. Due to recessing plates VC-FREIs were tested with higher scaling factors compared to RP-FREIs showing higher displacement capaci-ty with negligible residual. The building had no minor damage after the whole testing sequence with contents undergoing limited accelerations and displacements thus ensuring functionality even after major earthquakes. Thu, 01 May 2025 00:00:00 GMT http://repositorio.lnec.pt:8080/jspui/handle/123456789/1019475 2025-05-01T00:00:00Z http://repositorio.lnec.pt:8080/jspui/handle/123456789/1019470 Title: Nonlinear response analyses of a 2-storey RC building with fibre-reinforced elastomeric isolators Authors: Medaglia, P.; Losanno, D.; Parisi, F.; Lachanas, C.; Ribeiro, F.; Correia, A.A. Editors: M. Papadrakakis; M. Fragiadakis Abstract: Base isolation (BI) is one of the most promising techniques for seismic risk mitigation. How-ever, the high cost of traditional isolators undermines the systematic implementation of BI sys-tems in both new and existing buildings. In the last decade, fibre-reinforced elastomeric isolators (FREIs) have been developed as a promising low-cost alternative to steel reinforced elastomeric isolators. This study presents a numerical investigation on a three-dimensional, two-storey reinforced concrete (RC) frame designed for gravity loads only, which is representa-tive of a recurrent situation in many existing European buildings even in earthquake-prone areas. The specimen was base isolated with innovative FREIs and was subjected to shaking table tests at LNEC, Lisbon, Portugal, within the ERIES-FREISUST research project. This pa-per presents the main outcomes of the numerical modelling of the building specimen. In a first stage, the building was analyzed through a pushover analysis in fixed-based configuration to identify the global seismic capacity, damage progression, and collapse mechanism. The influ-ence of infill walls along one horizontal direction was also addressed by the model, showcasing its significant contribution to the lateral resistance. The FREI BI system was designed to achieve a target isolation period lower than 2 s. Assuming a Bouc-Wen hysteretic model of FREIs, which was calibrated based on experimental tests, the specimen response was investi-gated via nonlinear time history analysis (NLTHA). Based on the expected displacement ca-pacity of the BI devices, both ordinary and pulse-like ground motion records were selected to be representative of medium-to-high seismicity regions and to finely tune the performance level of FREIs. Both horizontal components of ground motions were imposed to the model. NLTHA demonstrated adequate filtering effect of the isolation system with no damage to both structural and non-structural building components, confirming the experimental observations from the shaking table tests and the effectiveness of FREIs for applications to housing projects. Sun, 01 Jun 2025 00:00:00 GMT http://repositorio.lnec.pt:8080/jspui/handle/123456789/1019470 2025-06-01T00:00:00Z