Abstract
Cracking damage influences the stiffness of the girders. Many articles in the literatures have studied the development of stiffness of the scale‐down model; however, full‐scale model testing cannot be completely replaced by scale‐down testing because of material component characteristics and boundary effects. This paper deals with the effects of cracking damage on the structural static and dynamic stiffness based on three prestressed concrete (PC) girders which were removed from an old bridge. First, the equivalent flexural rigidity of cracked prestressed concrete girder was assessed using the measured load‐deflection response under cycles of loading and unloading. Then, after unloading, the frequencies were measured on the PC girders supported by the elastomeric bearings. Next, the development of frequency under different damage was studied, and finally, the dynamic stiffness of PC girders with cracks was assessed. The results indicate that the first frequency is more sensitive to the cracking of concrete compared with the second frequency and that the mode shapes are not sensitive to girder damage. The test girders cannot be simplified as an ideal simply supported beam for the purpose of identifying frequencies. In addition, the “final” (the end of the ultimate load case) equivalent flexural rigidity of the girders is 30% of the “initial” (the beginning of the first load case) equivalent flexural rigidity, compared with 50% in the scale‐down test; and the final dynamic stiffness is approximately 84% of the initial dynamic stiffness, whereas the scale‐down test is 72%.
Highlights
Prefabricated prestressed concrete (PC) girders are widely used in bridge engineering
When a cracked reinforced concrete (RC) member is subjected to loading, the moment of inertia of section is degraded due to cracking and poor bonding between steel and concrete. ese effects must be considered in the serviceability analysis of existing cracked RC members [1, 2]
Xu and Castel studied the effects of steel-concrete bond damage on the dynamic stiffness of cracked RC beams under low-amplitude vibration. ey found that considering the effect of bending cracks and neglecting the steel-concrete bond loss were in good agreement with both free and lowamplitude forced vibration test results [5], and they found that localized steel-concrete bond damage did not influence the dynamic stiffness or natural frequency of a beam significantly, with or without sustained loading [6]
Summary
Prefabricated prestressed concrete (PC) girders are widely used in bridge engineering. Xu and Castel studied the effects of steel-concrete bond damage on the dynamic stiffness of cracked RC beams under low-amplitude vibration. Ey found that considering the effect of bending cracks and neglecting the steel-concrete bond loss were in good agreement with both free and lowamplitude forced vibration test results [5], and they found that localized steel-concrete bond damage did not influence the dynamic stiffness or natural frequency of a beam significantly, with or without sustained loading [6]. Capozucca performed experimental research on real-scale PC/RC beam models using vibration tests on free-free end condition beams. E aim of this study is to identify dynamic stiffness under elastic boundary conditions and to explore the relationship between stiffness and crack damage. The relationship between static and dynamic stiffness is analyzed
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
