Giovanni P. Terrasi

Swiss Federal Laboratories for Materials Science and Technology

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

Luke Bisby

University of Edinburgh

Cristián Maluk

University of Queensland

Michel Barbezat

Swiss Federal Laboratories for Materials Science and Technology

Christian Affolter

Swiss Federal Laboratories for Materials Science and Technology

Janet M. Lees

University of Cambridge

Urs Meier

Swiss Federal Laboratories for Materials Science and Technology

Bernhard Weisse

Swiss Federal Laboratories for Materials Science and Technology

Eleni Toumpanaki

University of Bristol

Erich Hugi

Swiss Federal Laboratories for Materials Science and Technology

G. Piskoty

Swiss Federal Laboratories for Materials Science and Technology

Cooperative Institutions

Swiss Federal Laboratories for Materials Science and Technology

ETH Zurich

University of Edinburgh

École Polytechnique Fédérale de Lausanne

University of Mumbai

University of Cambridge

Board of the Swiss Federal Institutes of Technology

University of Queensland

Adolfo Ibáñez University

Queen's University

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Chemical prestressing of high-performance concrete reinforced with CFRP tendons

Composite Structures (2020)

Mateusz Wyrzykowski Giovanni P. Terrasi Pietro Lura

Shrinkage

Expansive

Tension (geology)

10.1016/j.compstruct.2020.112031

Cite

Citations (20)

20 Years of Experience with Structural Health Monitoring of Objects with CFRP Components

Rilem bookseries (2011)

Urs Meier Rolf Brönnimann P. Anderegg Giovanni P. Terrasi

Bridge (graph theory)

Structural Health Monitoring

Fiber Bragg Grating

Strain gauge

10.1007/978-94-007-0723-8_136

Cite

Citations (11)

Tensile behavior of unidirectional thick-Ply all-carbon hybrid laminates: a systematic experimental and numerical study

Composites Part C Open Access (2024)

Thomas Martinoni Valentin Ott Valter Carvelli Giovanni P. Terrasi

Unidirectional long fiber reinforced polymers generally exhibit unfavorable abrupt and brittle failure under mechanical stresses without pre-warning which currently limits their use in safety critical applications. The lack of ductility of such composites can be overcome by interlayer hybridization where Low Strain (LS) material is sandwiched between High Strain (HS) material. This results in complex failure mechanisms, including multiple interacting damage modes, such as ply fragmentation and delamination. All-carbon unidirectional hybrid laminates with different layup sequences were designed and manufactured to study the pseudo-ductile behavior. An available analytical model was exploited to predict the damage scenarios of the laminates, both with stress-strain diagrams and damage mode maps. Tensile tests were carried out using different measurement and observation techniques including digital image correlation (DIC), embedded distributed fiber optic sensors (dFOS) and helicoidal X-ray computed tomography (CT). A finite element model was also developed to predict the damage mechanisms. Validated by experimental results, the numerical model was found to accurately predict the tensile damage modes and their evolution in the considered unidirectional thick ply all-carbon hybrid laminates.

Brittleness

Digital image correlation

Delamination

Ductility (Earth science)

Ultimate failure

10.1016/j.jcomc.2024.100462

Cite

Citations (2)

Fire behavior of slender concrete beams prestressed with CFRP tendons

Erich Hugi Giovanni P. Terrasi Luke Bisby Cristián Maluk

Prestressed concrete

Source

Cite

Citations (0)

Effect of internal moisture content on the TG values of CFRP rods

Eleni Toumpanaki Janet M. Lees Michel Barbezat Giovanni P. Terrasi

© 2019 9th International Conference on Fibre-Reinforced Polymer (FRP) Composites in Civil Engineering, CICE 2018. All Rights Reserved. DMA tests are used for the material charaterisation of CFRP tendons for civil engineering applications and to assess the high temperature behavior of CFRP prestressed structures by measuring the glass transition temperature Tg. The glass transition temperature is sensitive to the moisture content of the CFRP tendons and standard test methods (e.g. ASTM D7028 (ASTM 2007)) have not yet qualitatively addressed the effect of small moisture content variations from environmental conditions in the Tg values. The effect of the internal moisture content on the Tg values of two CFRP rods with different diameters and manufacturing process is evaluated. Lab conditioned specimens with varying drying time (9, 15, 36 and 210 days) and thus moisture content are tested to study the effect of small lab conditions variations in the glass transition temperature and the sensitivity of the DMA testing. Exposed specimens at 60°C for roughly 3 years are also investigated to record effect of greater moisture absorption on the Tg values. Two heating runs were conducted for every test to differentiate post-curing effects and mass weight measurements were recorded before and after each heating run. A linear relationship between the mass loss of the specimens due to drying at vacuum and during the heating runs with the glass transition temperature Tg was observed. Post-curing effects could not be clarified even for the dry specimens. The exposed specimens showed a reduction in Tg of 38°C that was reversible after drying. It is recommended that the use of Tg values to infer the degree of curing should be carried out on dry specimens.

Rod

10.17863/cam.27288

Cite

Citations (1)

THERMO-MECHANICAL COMPATIBILITY OF CFRP VERSUS STEEL REINFORCEMENT FOR CONCRETE AT HIGH TEMPERATURE

Cristián Maluk Luke Bisby Giovanni P. Terrasi

Optimization of the design of concrete structures has become a driver for the use of nonconventional reinforcing materials. One example of this is the emerging use of non-corrosive, highstrength, and lightweight carbon fibre reinforced polymer (CFRP) prestressing tendons. It is widely known that the bond between FRP reinforcing tendons and concrete deteriorates at elevated temperature due to a combination of factors. Lateral thermal expansion of FRP reinforcing tendons at elevated temperature has been shown to have consequences for the bond performance of these systems. This paper presents the results of an experimental study carried out to assess the occurrence of heat-induced longitudinal splitting cracks in concrete specimens reinforced with CFRP or steel prestressing tendons. A novel testing methodology, namely a Heat-Transfer Rate Inducing System (H-TRIS), is used to subject specimens to thermal loading which replicates that experienced by equivalent specimens in a standard fire resistance test. A comparison between CFRP and steel tendons is made, and the occurrence of longitudinal splitting cracks is evaluated in terms of the time to occurrence and thermal gradient within the concrete. Results are compared against an available analytical model.

Temperature Gradient

Source

Cite

Citations (0)

Effects of Elevated Temperatures and Fire on Bond Strength of Prestressed Steel and Carbon FRP Bars in High Performance Self-Consolidating Concrete

Cristián Maluk Luke Bisby Hernán Santa María Giovanni P. Terrasi Erich Hugi

Novel structures are emerging utilizing high performance, self-consolidating, fibre-reinforced concrete (HPSCC) reinforced with high-strength, lightweight, and non-corroding prestressed reinforcement. One example of this is a new type of precast carbon fibre reinforced polymer (CFRP) pretensioned HPSCC panel intended as load-bearing panels for building envelopes. As for all load-bearing structural members in building applications, the performance of these members in fire must be understood before they can be used with confidence. In particular, the bond performance of CFRP prestressing reinforcement at elevated temperatures is not well known. This paper examines the fire performance of these new types of structural elements, placing particular emphasis on the bond performance of CFRP and steel wire prestressing reinforcement at elevated temperatures. The results of large scale fire tests and bond-pullout tests on CFRP and steel prestressing bars embedded in HPSCC cylinders are presented and discussed to shed light on the fire performance of these structural elements. An analytical model is proposed to determine the temperature at which first appearance of the cracking phenomenon and concrete cover failure occurred, in the large scale fire tests, due to incompatibility of thermal expansion between CFRP tendons and HPSCC. From this research it is proposed that temperatures in range of the glass transition temperature (Tg) of the CFRP tendon’s epoxy matrix are critical for the bond strength capacity of the CFRP tendons in reinforced or pretensioned concrete members.

Precast concrete

Fire test

Fire performance

Concrete cover

Prestressed concrete

Source

Cite

Citations (0)

Development of a Pretensioning Anchorage for Sand-Coated CFRP Tendons: Modeling and Validation

Polymers (2022)

Gian-Luca Züst Valentin Ott Giovanni P. Terrasi

This paper presents a finite element (FE) analysis of an anchor for prestressing of sand-coated carbon-fiber-reinforced polymer (CFRP) tendons during the manufacturing of precast elements. This anchorage is temporary and removed after 2 to 7 days, when the pretensioning is released and the concrete is finally compressed. The investigated anchor consists of a conical metal barrel and three polymer wedges. The main tendon material properties are measured, compared with theoretical values and define the basis for the FE model. The latter considers both steps, pressing-in of the wedges and the subsequent loading of the tendon (diameter 7.5 mm). The relatively soft contact between polymer wedge and sand-coating is characterized experimentally and implemented with a pressure-overclosure condition. For the validation of the FE model, the strain distribution in the tendon is measured using fiber optical sensing. The therefore crucial process of fiber integration is described, and a novel approach is presented to uncover the optical fiber. The strain distribution of a sample with two anchors loaded in tension up to 80 kN is presented. The stress concentration at the front of the anchorage is highlighted. In addition, the finite element model is compared with the experiment, showing a good agreement of the strain distribution. A failure criterion according to Puck is finally implemented, which allows to assess potential fiber or interfiber failure.

Tension (geology)

Wedge (geometry)

Precast concrete

10.3390/polym14245531

Cite

Citations (6)

Fretting Fatigue Performance of Unidirectional, Laminated Carbon Fibre Reinforced Polymer Straps at Elevated Service Temperature

Polymers (2021)

Danijela Stankovic Luke Bisby Zafiris Triantafyllidis Giovanni P. Terrasi

The fretting fatigue performance of laminated, unidirectional (UD), pin-loaded, carbon fibre-reinforced polymer (CFRP) straps that can be used as bridge hanger cables was investigated at a sustained service temperature of 60 °C. The aim of this paper is to elucidate the influence of the slightly elevated service temperature on the tensile fatigue performance of CFRP straps. First, steady state thermal tests at ambient temperature and at 60 °C are presented, in order to establish the behaviour of the straps at these temperatures. These results indicated that the static tensile performance of the straps is not affected by the increase in temperature. Subsequently, nine upper stress levels (USLs) between 650 and 1400 MPa were chosen in order to establish the S-N curve at 60 °C (frequency 10 Hz; R = 0.1) and a comparison with an existing S-N curve at ambient temperature was made. In general, the straps fatigue limit was slightly decreased by temperature, up to 750 MPa USL, while, for the higher USLs, the straps performed slightly better as compared with the S-N curve at ambient temperature.

10.3390/polym13193437

Cite

Citations (2)

The influence of feedback and convection on imposed heating conditions when using gas-fired radiant panels in fire testing

Fire Safety Journal (2023)

Hussein Cadosch David Morrisset Angus Law Giovanni P. Terrasi Luke Bisby

Gas-fired radiant panel arrays (RPAs) are a common experimental tool used in fire science and material testing. Unlike devices such as Cone Calorimeter or the Fire Propagation Apparatus (FPA), RPAs typically consume gaseous fuel within a porous medium through which fuel is burnt. When RPAs are used, thermal feedback from the surface of heated samples, as well as the effects of hot gases within the zone of convective influence of the RPA will cause an increase in the surface temperature of the RPA. To investigate this, experiments were conducted using a gas-fired RPA. Target samples made from vermiculite board, concrete, and a water-cooled aluminium plate were exposed to various severities of pre-calibrated incident radiant heat fluxes (HF). It was confirmed that the presence of a target sample led to an increased surface temperature for the RPA of nearly 80 °C (for a calibrated incident HF of 144 kW/m2). This increased surface temperature results in an incident HF nearly 78% higher than the pre-calibrated value at the sample's surface. Based on the results in this paper, a correction method has been proposed which can be used by gas-fired RPA users to account for the increase in incident heat fluxes.

Cone calorimeter

Radiant heat

Flame spread

Calorimeter (particle physics)

10.1016/j.firesaf.2023.104013

Cite

Citations (0)