Document Type : Research Paper
Authors
1
Ph.D. Student of Structure Engineering, Civil Engineering Department, Islamic Azad University, Shahrood, Iran
2
Assistant Professor, Faculty of Civil Engineering, Shahrood Branch, Islamic Azad University, Shahrood, Iran
3
MSc, Structural Engineering, Faculty of Engineering, Islamic Azad University, Shahroud, Iran
Abstract
The use of cross -sectional openings in bridges reinforced concrete beams to pass the installation can reduce the height of the bridge deck , thereby reducing the overall height and anchorage of the foundation and increasing the effective height under the bridges. On the other hand, the use of opening in the beams will cause stress at critical points around the openings, reducing the bearing capacity of the beams, excessive deformation and redistribution of force to other members. In this study, the behavior of reinforced concrete beams with circular cross-sectional openings is investigated using finite element method and with application of Abacus software, the experimental results of 28-day concrete beam specimen accuracy are investigated for validity. In this experiment, two symmetrical loads, 40 cm apart, were used incrementally for loading. After verifying the modeling accuracy and comparing the analytical and laboratory results, it was found that the finite element modeling results are near the laboratory data. Parameters such as circular openings dimensions in beam, relative position of circular openings in height and length of beam and effect of proposed steel sheath on openings are the issues that have been investigated in subsequent modeling. The results showed that the small bars at the top and bottom of the openings and around the openings increased the final load of the open beam to near the final load of the first beam. The use of the proposed steel sheath at the openings area increased the bearing capacity of the beam by approximately 30%. Therefore in compared with the capacity of the first beam, 3 Percentage of difference observed.
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