During service period, due to the overload or other non-load factors, diagonal cracks of the pre-stressed concrete beam are seriously affecting the safety of the bridge structure. The purpose of this paper is to quickly realize the shear bearing capacity and shear stiffness through maximum width of the diagonal cracks and make correct judgments.
Through the shear failure test of four test beams, collecting data of diagonal cracks and shear stiffness loss value. According to the deformation curve of the shear stiffness, and combined with the calculation formula of the maximum width of diagonal cracks, the formula for calculating the effective shear stiffness based on the maximum width of diagonal cracks is deduced, then the results are verified by test data. Data regression method is used to establish the effective shear stiffness loss ratio calculation formula, the maximum width of diagonal cracks used as a variable factor, and the accuracy of this formula is verified by comparing the shear failure test results of pre-stressed hollow plates.
With the increase in width of the diagonal crack, the loss rate of shear stiffness of the concrete beams is initially fast and then becomes slow. The calculation formulae for shear stiffness based on the maximum width of the diagonal cracks were deduced, and the feasibility and accuracy of the formulae were verified by analysis and calculation of shear test data.
A method for quickly determine the shear stiffness loss of structures by using maximum width of the diagonal cracks is established, and using this method, engineers can quickly determine effective shear stiffness loss ratio, without complex calculations. So this method not only ensures the safety of human life, but also saves money.
Conflict of interest: the authors declare that there are no conflicts of interest regarding the publication of this article.
This study was supported by “the Fundamental Research Funds for the Central Universities” (No. 2572017AB01), “Natural Science Foundation of Heilongjiang Province of China” (Grant No. E2017003) and Transportation Science and Technology Project of Liaoning Province of China (Nos 201512 and 201513).
Liu, J., Jia, Y., Zhang, G. and Wang, J. (2018), "Effect of diagonal cracks on shear stiffness of pre-stressed concrete beam", International Journal of Structural Integrity, Vol. 9 No. 4, pp. 414-428. https://doi.org/10.1108/IJSI-07-2017-0042Download as .RIS
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