FRP-Quake – Seismic Behaviour and Ductility of Structures Built with Glass Fibre Reinforced Polymers
Project PTDC/ECM-EST/6465/2014 funded by Fundação para a Ciência e a Tecnologia (FCT)
Partners IST
Total funding € 183,790.00
IST funding € 183,790.00
Period 2016-2020
Summary
This project addressed the seismic behaviour or pultruded glass fibre reinforced polymer (GFRP) structures and the development of innovative constructive solutions that promote their energy dissipation capacity, through the integration of innovative connection and bracing systems.
GFRP profiles are a recent promising alternative to traditional materials, for both new construction and rehabilitation, due to their high strength, durability and reduced maintenance. Furthermore, in densely urbanized districts, their lightness and easy assembly allow reducing construction costs and duration.
However, the lack of specific regulation and the typical brittle failure of GFRP materials (in contrast with current design practice aiming at exploiting material ductility) have hampered their widespread use, especially in seismic areas, where there are well-founded concerns and uncertainty about their seismic response.
At the same time, GFRPs are currently used as energy dissipators in automotive, naval and aerospace industries, where progressive/ductile failure modes have been exploited. This type of behaviour, which may be beneficial under seismic action, was never studied in civil engineering applications.
Therefore, to enable a widespread use of GFRP structures in construction, with the consequent socio-economic benefits, it is of the utmost importance to study their seismic behaviour, to develop material-adapted connection and bracing systems with improved ductility and to develop/adapt seismic design rules.
In order to develop GFRP structural solutions with adequate seismic behaviour, this project developed beam-to-column connection systems with improved ductility, enhancing the inelastic energy dissipation capacity of GFRP structures, and proposing seismic analysis and design rules.
A comprehensive experimental study was conducted including (i) mechanical characterization tests on the GFRP material, with particular focus on its fracture; (ii) monotonic and cyclic tests on beam-to-column connections (conventional and improved); and (iii) monotonic and cyclic sway tests in a reaction wall of 2D frames, with different connections systems, bracing and partition walls, and (iv) in a shaking table tests in a two-storey 3D frame, with and without bracings. The novel connection systems studied included (i) composite connections, combining bolting and bonding (with ductile adhesives), and (ii) connections with stainless steel components. The new bracing system were materialized by stainless steel cables.
The numerical study included the development of finite element (FE) models to simulate: (i) the GFRP material characterisation tests, resulting in the development of a new damage progression model for fibre composites; (ii) connection tests, modelling the GFRP material and the contacts at the various interfaces; and (iii) the frame tests, considering the constitutive laws of the materials and connections defined previously.
The project resulted in the (i) in-depth understanding about the static and dynamic responses of GFRP structures at different levels (material, component, connection and structure), including the fracture behaviour, damping and ability to dissipate inelastic energy; the development of (ii) a new damage progression model for composite materials, and of (ii) GFRP structures with adequate seismic performance, comprising innovative ductile connection systems, and a set of guidelines for the (iii) seismic analysis and design of GFRP structures (following Eurocode 8).
Main Publications:
J. Gonilha, D. Martins, J.R. Correia, N. Silvestre, L. Guerreiro, “Seismic response of three-dimensional pultruded GFRP frames”, Journal of Composites for Construction, accepted for publication on 02/01/2024.
D. Martins, J. Gonilha, J.R. Correia, N. Silvestre, “Monotonic and cyclic sway behaviour of 2-dimensional frames made of pultruded GFRP I-section profiles”, Structures, Vol. 55, 2461-2477, 2023.
https://doi.org/10.1016/j.istruc.2023.07.035
J. Gonilha, D. Martins, “Numerical simulation of the damage progression of pultruded GFRP beam-to-column connections under monotonic and cyclic loads”, Composite Structures, Vol. 300, 116180, 2022.
https://doi.org/10.1016/j.compstruct.2022.116180
D. Martins, J. Gonilha, J.R. Correia, N. Silvestre, “Monotonic and cyclic behaviour of a stainless steel cuff system for beam-to-column connections between pultruded I-section GFRP profiles”, Engineering Structures, Vol. 249, 113294, 2021.
https://doi.org/10.1016/j.engstruct.2021.113294
D. Martins, J. Gonilha, J.R. Correia, N. Silvestre, “Monotonic and cyclic behaviour of cuff beam-to-column connection system for tubular pultruded GFRP profiles”, Engineering Structures, Vol. 247, 113165, 2021.
https://doi.org/10.1016/j.engstruct.2021.113165
D. Martins, J. Gonilha, J.R. Correia, N. Silvestre, “Exterior beam-to-column bolted connections between GFRP I-shaped pultruded profiles using stainless steel cleats, Part 2: Prediction of initial stiffness and strength”, Thin-Walled Structures, Vol. 164, 107762, 2021.
https://doi.org/10.1016/j.tws.2021.107762
D. Martins, J. Gonilha, J.R. Correia, N. Silvestre, “Exterior beam-to-column bolted connections between GFRP I-shaped pultruded profiles using stainless steel cleats. Part 1: Experimental study”, Thin-Walled Structures, Vol. 163, 107719, 2021.
https://doi.org/10.1016/j.tws.2021.107719
J.A. Gonilha, N. Silvestre, J.R. Correia, V. Tita, D. Martins, “Novel progressive failure model for quasi-orthotropic pultruded FRP structures: Formulation and calibration of parameters (Part I)”, Composite Structures, Vol. 255, 112974, 2021
https://doi.org/10.1016/j.compstruct.2020.112973
J.A. Gonilha, N. Silvestre, J.R. Correia, V. Tita, L. Almeida-Fernandes, “Novel progressive failure model for quasi-orthotropic pultruded FRP structures: Application to compact tension and web-crippling case studies (Part II)”, Composite Structures, Vol. 255, 112973, 2021.
https://doi.org/10.1016/j.compstruct.2020.112974
D. Martins, M. Proença, J.A. Gonilha, M.F. Sá, J.R. Correia, N. Silvestre, “Experimental and numerical analysis of GFRP frame structures. Part 1: Cyclic behaviour at the connection level”, Composite Structures, Vol. 220, pp. 304-317, 2019
https://doi.org/10.1016/j.compstruct.2019.03.098
D. Martins, M.F. Sá, J.A. Gonilha, J.R. Correia, N. Silvestre, J.G. Ferreira, “Experimental and numerical analysis of GFRP frame structures. Part 2: Monotonic and cyclic sway behaviour of plane frames”, Composite Structures, Vol. 220, pp. 194-208, 2019.