Mechanical behaviour of brick masonry arches strengthened by GFRP sheet and CFRP plates (original) (raw)
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Experimental Behavior of FRP Strengthened Masonry Arches
Journal of Composites for Construction, 2010
This paper deals with the experimental behavior of solid clay brick masonry arches strengthened with glass fiber reinforced polymer composites. Twelve half-scaled segmental masonry arches subjected to a load applied at the quarter span were tested under displacement control up to failure. The arches were built using handmade low strength bricks and a commercial lime-based mortar, trying to mimic ancient structures. Besides reference unreinforced arches, five different strengthening arrangements, including the use of spike anchors, were studied. The experimental results provide significant information for validation of advanced numerical models and analytical tools, and for code drafting. The experimental results also show that: (1) only continuous strengthening strategies are able to prevent typical local failure mechanisms of unreinforced arches;
MATEC Web of Conferences
In recent years fiber-reinforced polymers (FRP) have been widely used for strengthening masonry structures. In particular, in the case of masonry arches, the use of FRP sheets increases load-bearing capacity by limiting or preventing the occurrence of tensile cracks that could activate collapse mechanisms. The effectiveness of the strengthening intervention depends on the bond between FRP and substrate, due to the shear and normal stresses that occur in the bond interface, so much so that the typical failure mode of an arch reinforced with narrow FRP sheets at the intrados is exactly delamination. In this paper a predictive numerical procedure of the combined mode I and mode II failure is proposed. Numerical results provided by this procedure are compared to the experimental results on in-scale arch models taken from a recent work of the author.
Intrados strengthening of brick masonry arches with composite materials
Composites Part B: Engineering, 2011
The objective of this study is to investigate the effectiveness of an innovative technique for strengthening masonry arches at their intrados, based on the use of carbon plates. Although FRP sheets or strips are successfully used as strengthening elements for this kind of application, they present several critical issues that can compromise these upgrading works, leading to the local collapse mechanism, which corresponds to the debonding of reinforcement from the masonry substrate. As an alternative to FRP sheets, the use of FRP plates presents instead several interesting aspects which make them very attractive for intrados strengthening. More precisely, FRP plates have an inherent bending and axial stiffness that may overcome problems concerning premature peeling. Fifteen prototypes of brickwork arches strengthened at their intrados with GFRP sheets or CFRP plates were tested under a monotonic vertical load applied at the keystone. The influence of the types of reinforcement (glass fibers and carbon plates), properties of the bonding system and masonry substrate and the presence of anchor spikes has been investigated.
Strengthening of Masonry Arches with Fiber-Reinforced Polymer Strips
Journal of Composites for Construction, 2004
This paper deals with masonry arches and vaults strengthened with surface fiber-reinforced polymer ͑FRP͒ reinforcement in the form of strips bonded at the extrados and/or intrados, considering strip arrangements that prevent hinged mode failure, so the possible failure modes are: ͑1͒ crushing, ͑2͒ sliding, ͑3͒ debonding, and ͑4͒ FRP rupture. Mathematical models are presented for predicting the ultimate load associated with each of such failure modes. This study has shown that the reinforced arch is particularly susceptible to failure by crushing, as a result of an ultimate compressive force being collected by a small fraction of the cross section. Failure by debonding at the intrados may also be an issue, especially in the case of weak masonry blocks or multiring brickwork arches. Failure by sliding has to be considered if the reinforcement is at the extrados and loading is considerably nonsymmetric.
Materials and Structures, 2008
Assessment of the effects of the application of advanced materials and new technologies on traditional structures has assumed a major relevance within the ongoing debate on the preservation of historic buildings. The aim of the present paper is to discuss the validity of analytical models, by means of experimental investigations carried out on masonry arches reinforced with CFRP strips, bonded at the intrados or extrados with distinct configurations. A theoretical prediction of ultimate strength for the different reinforcement configurations was derived in agreement with the occurrences observed during the experiments (masonry crushing, FRP rupture, debonding, sliding along the mortar joint). The results of the experimental trials allowed not only to validate the proposed analytical derivations but also to evaluate the impact of different reinforcement configurations on the strength of masonry arches and then to deduce considerations on sizing criteria for the CFRP strengthening of traditional masonry structures.
In this paper, the effect of several brick and mortar mechanical and microstructural parameters on the maximum debonding force of the same glass fiber reinforced polymer (GFRP), applied on different bricks and on corresponding masonry panels, was investigated. GFRP sheets were bonded by epoxy resin to four different types of solid fired-clay brick and four types of masonry panels, manufactured using the same bricks and a natural hydraulic lime mortar . The reinforced specimens were subjected to bond tests to evaluate the maximum debonding force. Bricks and mortar were characterized in terms of compressive strength (in the case of bricks, along two different orthogonal directions, , surface roughness and pore size distribution. The results of the study suggest that brick mechanical properties are not the only parameters that influence the maximum debonding force . In fact, also surface roughness and pore structure seem to significantly affect the examined specimens behavior.
Numerical and Experimental Analysis of Full Scale Arches Reinforced with GFRP Materials
Key Engineering Materials, 2014
In this contribution, original limit analysis numerical results are presented dealing with some reinforced masonry arches tested at the University of Minho-UMinho, PT. Twelve in-scale circular masonry arches were considered, reinforced in various ways at the intrados or at the extrados. GFRP reinforcements were applied either on undamaged or on previously damaged elements, in order to assess the role of external reinforcements even in repairing interventions. The experimental results were critically discussed at the light of limit analysis predictions, based on a 3D FE heterogeneous upper bound approach. Satisfactory agreement was found between experimental evidences and the numerical results, in terms of failure mechanisms and peak load.