Estimating the flexural strength of corroded reinforced concrete beams based on rectangular compressive stress block

Effect of different material constitutive models in estimating the residual moment capacity of RC beams subjected to natural corrosion

“…Nevertheless, an inverse relationship between C f and ω is expected and well-known. Previous studies have attributed the decrease to various consequences associated with rebar corrosion, including loss of bond between the rebars and concrete, concrete cracking and spalling, or decrease in strength of rebars caused by the reduction in their cross-sectional area (Ahmad, 2017;Azad et al, 2010;Tintero et al, 2023). Interestingly, existing data demonstrating such behavior were derived primarily from accelerated conditions.…”

“…Multilinear regression analysis was then performed to express C f as a linear function of four variables: tensile bar diameter (D o ), clear bar cover at tension side (C v ), corrosion degree (ω), and center-to-center span length (L s ). They were selected as explanatory variables because of earlier studies showing that they influence the flexural strength of corroded beams (Ahmad, 2017;Azad et al, 2010;Tintero et al, 2023). The newly developed expressions (now denoted as C * f ) were introduced as a multiplier to the theoretical moment to account for the difference between the calculated values and experimental data due to the non-uniformity of corrosion Residual moment capacity of RC beams and other consequences as the beams undergo progressive damage, including concrete-rebar bond loss, volumetric expansion of rust, concrete cracking, and concrete spalling.…”

“…This combination, together with the associated C * f (Table 5), was then compared to earlier works to verify the accuracy of the current approach. The earlier models considered were those of Tintero et al (2023) and Azad et al (2010), in which M th was computed by the equivalent rectangular stress block concept, while the corrosion coefficient is based on accelerated corrosion. The errors (or percentage differences) between M ex, obtained from the current study, and M cal , computed analytically by different approaches, are shown in Figure 13.…”

“…Azad et al (2010) also derived a similar deterministic factor using larger beam specimens to account for the size effect. Tintero et al (2023) made a follow-up study to improve the accuracy of the equations by incorporating more data from the literature. The work by O'Flaherty and Browne (2019) proposed a moment coefficient that can be multiplied by f ck bd 2 (where f ck is the compressive strength of concrete cylinder, b is the beam width, and d is the distance of reinforcement centroid to extreme compression fiber).…”

Investigating the Flexural Behavior of a Two-Span High-Performance Concrete Beam Using Experimentally Derived Stress Block Parameters

“…Designing HPC beams to withstand flexure can be a challenging task, as most standard codes and methods used for NSC cannot be applied to HSC. , To study the flexural behavior of higher-strength concretes, researchers have put forward stress block parameters and verified their experimental results, proposing substantial changes to current codes. − Stress block parameters have also been proposed for special types of concretes, such as geopolymer concrete (GPC). , However, it is unclear whether these parameters can be applied to HPC. While the ultimate strain of concrete recommended by the American code 441-R96 is 0.003, other codes such as EC-2, Canadian code, and IS Code limit it to 0.0035.…”