Round Robin Test for composite-to-brick shear bond characterization

Abstract

The paper presents the experience of a working group within the RILEM Technical Committee 223-MSC ‘Masonry Strengthening with Composite materials’, aimed at developing a standardized, reliable procedure for characterizing the bonding mechanism of masonry elements strengthened with composite materials under shear actions. Twelve laboratories from European universities and research centers were involved. Two different set-ups were compared, for single-lap and double-lap shear tests (the latter in two versions). Four kinds of fiber fabrics, i.e., glass, carbon, basalt and steel, were applied with epoxy resins (wet lay-up system) to clay brick units, for a total of 280 monotonic tests. The results provided information regarding the response of externally bonded-to-brick composites in terms of observed failure mechanisms, load capacity, effective transfer length, and bond shear stress–slip behavior. The test results of the 12 laboratories constitute a set of statistically representative data which may conveniently be used for setting appropriate design provisions and guidelines

A review on the bond behavior of FRP composites applied on masonry substrates

“…Extended experimental campaigns on the same substrate material (single bricks or masonry panels) strengthened with different types of FRPs, carried out within different RILEM Round Robin Test (RRT) series [9,10], involving several laboratories and universities, confirmed the typical failure modes highlighted by the other authors with a predominance of the cohesive debonding of the composite material from the substrate with a thin layer of detached material ( Fig. 1).…”

“…In order to acquire a proper knowledge of the bond behavior of FRP composite materials when applied on masonry substrates, experimental bond tests have been carried out by several authors, working on single bricks or on masonry panels specimens [9][10][11].…”

“…Niedermeier [75,85] Starting from the proposed formulation (1), another calibration of design parameters, performed using experimental data collected during two different Round Robin Tests series [9,10] and following the approach proposed in [80,81], is discussed in [10].…”

“…Results coming from different Round Robin Test activities, carried out by different laboratories and universities [9][10][11], will also be discussed, in order to critically investigate similarities and differences coming from experimental outcomes.…”

Nonlinear Modelling of Curved Masonry Structures after Seismic Retrofit through FRP Reinforcing

“…When it comes to retrofitting techniques, and in particular to fibre-composite strengthened structures, a crucial aspect is related to the correct simulation of the tangential stress transferred from the reinforcement to the masonry substrate, and the relative failure collapse for tensile rupture of the textile or delamination of the reinforcement from the support. On this task, several contributions have been given by different authors and now are available in the literature [6][7][8][9], also in presence of curved support [10,11].…”