Effect of unbonded prestressing steel in terms of serviceability

Effect of unbonded prestressing steel in terms of serviceability

Článek WoS

Prestressed concrete is one of the most important construction technologies, which has had a significant impact on the development of bridge construction and other areas. It utilizes the advantages of concrete itself, specifically its compressive strength, in combination with high tensile strength of prestressing steel thereby significantly increasing the ultimate strength of structure. By applying compressive force to the concrete through prestressing tendons, a compressive reserve is created in areas subject to tensile stressed under loading, which also helps to reduce deformations and crack formation, this is described and illustrated in more detail in chapter 2. An example of this is the additional strengthening of an existing bridge structure using external (unbonded) prestressing steel, which, according to some studies (Naaman & Alkhairi, 1991), can increase the load capacity by several times compared to the original design. However, prestressed concrete structures must meet not only the ultimate limit state (ULS) requirements-preventing collapse due to loss of load capacity, but also the serviceability limit state (SLS), which governs criteria such as deflections and crack widths, ensuring the structure remains safe and functional throughout its service life.

Prestressed concrete is one of the most important construction technologies, which has had a significant impact on the development of bridge construction and other areas. It utilizes the advantages of concrete itself, specifically its compressive strength, in combination with high tensile strength of prestressing steel thereby significantly increasing the ultimate strength of structure. By applying compressive force to the concrete through prestressing tendons, a compressive reserve is created in areas subject to tensile stressed under loading, which also helps to reduce deformations and crack formation, this is described and illustrated in more detail in chapter 2. An example of this is the additional strengthening of an existing bridge structure using external (unbonded) prestressing steel, which, according to some studies (Naaman & Alkhairi, 1991), can increase the load capacity by several times compared to the original design. However, prestressed concrete structures must meet not only the ultimate limit state (ULS) requirements-preventing collapse due to loss of load capacity, but also the serviceability limit state (SLS), which governs criteria such as deflections and crack widths, ensuring the structure remains safe and functional throughout its service life.

Unbonded tendon; Strengthening structures; Primary protection; Stress redistribution; Friction loss.

Unbonded tendon; Strengthening structures; Primary protection; Stress redistribution; Friction loss.

MUROŇ, V.; KLUSÁČEK, L.; SVOBODA, A.

26.11.2025

Civil and Environmental Engineering

November 2025

Slovenská republika

11

https://reference-global.com/article/10.2478/cee-2026-0032