Seismic Retrofit of RC Columns with Continuous Carbon Fiber Jackets

TLDR

The study develops, validates, and implements a new seismic retrofit system for reinforced concrete columns. The retrofit system consists of continuous carbon fiber prepreg tows wound onto existing columns, with variable jacket thickness along the height based on experimentally validated design models, and design criteria for various seismic failure modes are applied to circular and rectangular columns with differing reinforcement ratios. Large‑scale bridge column model tests confirm that the carbon jackets are as effective as steel shell jacketing in achieving the desired inelastic deformation capacity, and the retrofit criteria also apply to other advanced composite jacketing systems with appropriate adjustments.

Abstract

The development, the validation, and the implementation of a new seismic retrofit system for reinforced concrete columns are described. The column jacketing system consists of continuous carbon fiber prepreg tows wound in an automated fashion onto existing circular or rectangular concrete columns, with variable jacket thickness along the column height based on experimentally validated design models. Jacket design criteria for various seismic column failure modes are described and detailed examples show their application to retrofits of columns with circular and rectangular column geometry, different reinforcement ratios, and detailing. The carbon jacket designs are validated through large-scale bridge column model tests and are found to be just as effective as steel shell jacketing in providing desired inelastic design deformation capacity levels. Furthermore, it is shown that the retrofit criteria and guidelines are also applicable to other advanced composite jacketing systems with appropriate considerations for differences in mechanical properties of the materials system, installation and curing technology, as well as jacket discontinuities.