Creep and failure of a full-size fiber-reinforced plastic pultruded frame

doi:10.1016/0961-9526(92)90005-Q

Composites Engineering

Volume 2, Issue 3, April 1992, Pages 213-215, 217-227

https://doi.org/10.1016/0961-9526(92)90005-Q Get rights and content

Abstract

The long-term creep and the short-term failure of a plane portal frame structure, constructed entirely of pultruded fiber-reinforced plastic (FRP) components, has been investigated both experimentally and analytically. Two, 6 feet high by 9 feet wide, plane portal frames were designed and constructured using standard “off-the-shelf” glass/vinylester pultruded beams, nuts and threaded rods produced by Creative Pultrusions, Inc. One frame was subjected to a constant long-term load and analyzed for its creep characteristics while the other was tested to failure under short-term loading. The creep analysis considered both the time-dependent response of the FRP structural members and the contribution of shear-deformation effects. The use of viscoelastic moduli in conjunction with a shear-deformable beam theory is detailed. Theoretical predictions are compared with the experimental data. Design recommendations are suggested for structural applications.

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This paper presents an experimental study about the monotonic and cyclic behaviour of beam-to-column connections between pultruded GFRP profiles with I-section, joined by means of stainless steel cuff connection parts. This study pursues a previous investigation by the authors in which custom stainless steel cuff parts were proposed for beam-to-column connections between pultruded tubular GFRP profiles, which presented very satisfactory performance under both monotonic and cyclic loading. A similar concept is now investigated for joining profiles with I-section shapes, which are more often used in civil engineering applications. Four series of full-scale beam-to-column connections were tested under monotonic loading, using stainless steel cuffs of two different plate thicknesses and lengths. The results show that higher cuff thickness and length provided higher initial stiffness and strength, with the cuff thickness being the most influential parameter. Conversely, the ductility of the connections decreased with increasing cuff thickness: the series with thinnest cuff parts presented the highest ductility. The series with the most ductile cuff part was also tested under cyclic loading and presented significant capacity to dissipate energy, but showed marked pinching. These results were compared to those of a stainless steel flange cleated connection system previously tested using the same GFRP I-section profiles: the connections using cuff parts presented worst mechanical behaviour than the cleated connections. This indicates that the cuff connection system is more efficient to join tubular sections than open sections, such as I-sections.
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The use of glass-fibre reinforced polymer (GFRP) cuff parts to join GFRP beams and columns has been object of several experimental and numerical studies in the past, which showed their improved mechanical performance when compared to connection systems that mimic steel structures, such as connections with GFRP web and/or flange cleats. The main objective of the study presented in this paper is to propose and assess a connection system – for tubular GFRP profiles –with similar cuff geometry, but made of stainless steel, in order to achieve higher ductility due to its inherent strain hardening, while maintaining the non-corrodibility capabilities of GFRP. Full-scale tests were performed on four different beam-to-column connection series using stainless steel cuffs with varying geometry and plate thickness. The experimental campaign comprised: (i) monotonic tests for all series; and (ii) cyclic tests for the series with the best performance in the monotonic tests. The monotonic response of the different series varied considerably. As expected, by increasing the plate thickness of the cuff, the initial stiffness and strength of the connections were substantially improved; on the other hand, the moment vs. rotation behaviour of connections with thinner cuff parts was more markedly non-linear and GFRP damage was delayed. Nevertheless, all connection series presented significant ductility, successfully making use of the stainless steel mechanical properties. For both monotonic and cyclic loading, the cuff connection system presented herein provided better mechanical performance than stainless steel sleeve connections developed earlier by the authors, namely regarding initial stiffness, overall strength and energy dissipation.
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^☆: Adapted from ASME PD Vol. 32, 1990, Composite Material Technology (Edited by D. Hui and T. J. Kozik). © ASME, New York. Permission by ASME to publish this paper is gratefully acknowledged.

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Creep and failure of a full-size fiber-reinforced plastic pultruded frame☆

Abstract

Compos. Struct

Compos. Sci. Technol

Composites

Composites

Properties of pultruded fiber reinforced plastic (FRP) structural members. Transportation Research Record 1223

Beam-to-column connections for pultruded FRP structures

Mechanism and mechanics of creep of platics

SPE Jl

26-Year creep and recovery of poly(vinyl chloride) and polyethylene

Polymer Engng Sci

Some short and long term loading characteristics of a double layer skeletal structure manufactures from pultruded composites