Investigation of an Effective Anchoring Length of CFRP Tapes Used to Strengthen Steel Thin-Walled Beams with a Rectangular Cross-Section Subjected to Four-Point Bending

Abstract

In order to design an optimal reinforcement of steel thin-walled beams with composite materials, it is worth analyzing two important, although often overlooked issues, which are the selection of the appropriate thickness of the adhesive layer and the effective anchoring length of the composite tape. This paper, which is part of a wider laboratory study devoted to the strengthening of thin-walled steel profiles, focuses on the second issue. The paper involves a description of laboratory four-point bending tests during which ten thin-walled steel beams made of a rectangular section with dimensions of 120 × 60 × 3 and a length of 3 m were tested. Two beams were taken as reference beams, and the other eight were reinforced using Sika CarboDur S512 carbon fiber composite tape, assuming four different effective anchorage lengths. The impact of the length of the anchoring of the composite tape on the value of the displacements and strains of the tested beams and on the value of the destructive load that caused tape detachment was analyzed. The following phase was numerical analyses carried out in the Abaqus program, which showed high consistency with the results of laboratory tests. In reference to the conducted tests, it was observed that the increase in the anchoring length of the composite tape has a slight impact on the change in the value of strains and displacements in the tested beams. Nevertheless, the increase in the effective anchorage length has a significant impact on the load value at which the composite tapes are detached from the surface of the steel thin-walled beam.

The Influence of Using Steel Tapes and Composite Materials on Reinforcing Hot-Rolled Steel Profiles

“…This approach made it possible to obtain results as close as possible to the experimental studies. Another research paper analyzed the effect of mesh density on the accuracy of the calculation results, and slight differences in the density magnitude do not significantly affect the results-which is further presented in the scientific publication [15]. Within the framework of the calculations carried out for the base material of the beam, i.e., S235 steel, an elastic-plastic material model was used based on the material data presented in the description of the research subject in this publication.…”

Analysis of the Impact of Using CFRP Tapes on the Performance of Bent Thin-Walled Beams Connected with a Sandwich Panel – Pilot Studies

“…In the paper [13], the authors defined the effective anchoring length of composite tapes as the minimum length that allows the transfer of the maximum load by composite tapes. Such anchoring length of tapes was determined as the most effective in the case of reinforcing sigma thin-walled beams, which is described in the paper [14]. In the article [14] also describes how to determine the effective anchorage length.…”

“…Such anchoring length of tapes was determined as the most effective in the case of reinforcing sigma thin-walled beams, which is described in the paper [14]. In the article [14] also describes how to determine the effective anchorage length. The CFRP tapes were bonded to the degreased and matted topmost layer of the thin-walled beams using SikaDur-30 adhesive.…”

“…The basic strength parameters of the steel and CFRP tape used in the study are compiled in Table 1. Strength parameters of the SikaDur-30 adhesive were taken from the manufacturer's catalog cards and quoted in [14] and [15] and in Table 1.…”