Optimization of partial interaction in bolted side-plated reinforced concrete beams

•The partial interaction in bolted-side-plated (BSP) beams is studied.•Theoretical and numerical studies are conducted to investigate its influence.•Two simple factors are used to indicate the degree of partial interaction.•A common value is recommended for these factors to simplify strengthening design.•Retrofitting schemes are proposed for lightly and moderately reinforced RC beams.

A computer simulation is conducted to evaluate the partial interaction and the performance of BSP beams, by indicating the degree of partial interaction in terms of strain and curvature factors. Results show that strengthening effects are controlled by these factors and flexural strength would be overestimated if partial interaction is not properly addressed. A parametric study has been carried out and optimized values for these factors are proposed. This study reveals the influence of partial interaction to the overall performance and the proposed value for the two factors is of great significance in simplifying the design procedure of BSP beams.