Title: Load Factors for Residual Capacity of Bridges Strengthened with Carbon Fiber-Reinforced Polymer

Author(s): Yail J. Kim, Yongcheng Ji, Woo-Tai Jung, Jae-Yoon Kang, and Jong-Sup Park

Publication: Structural Journal

Volume: 119

Issue: 5

Appears on pages(s): 17-29

Keywords:

DOI: 10.14359/51732988

Date: 9/1/2022

Abstract:
This paper presents load factors for the residual capacity of highway bridges strengthened with carbon fiber-reinforced polymer (CFRP) composites. These load factors are intended to reflect structural loadings when a CFRP system malfunctions, so that a catastrophic event is prevented. To determine dead and live load factors under such an unordinary situation, stochastic inverse models are formulated per measure theory. Various bridge configurations and structural loadings are sampled from those used for calibrating the American Association of State Highway and Transportation Officials (AASHTO) Load and Resistance Factor Design (LRFD) Bridge Design Specifications (BDS). With an increase in span length over 18.3 m (60 ft), the dead load controls the response of the bridges relative to the live load. In accordance with inverse standard normal distributions, the live load effects are appropriate for representing service loadings (37.7% of the 75-year ultimate load effects, on average), which can thus be coupled with the residual capacity of the strengthened bridges. The most probable values are mathematically calculated to estimate the dead and live factors, and their influence is investigated on the moment and shear of the bridges. Analytical approaches, such as exceedance probability and safety index, substantiate that the calculated load factors outperform the load factors stipulated in a published design guideline. For the evaluation of residual capacity, the dead and live load factors are proposed to be 1.05 and 0.60, respectively.