| Popis: |
Glue joints make precast concrete segmental beams with discontinuity, which is the weak link and an important part of the structure and needs to be given special attention in practical engineering. To test the shear behavior of five segmental glue joint beams and one monolithic beam, the test parameters included shear span ratios (1.2, 1.5), prestress levels (4 MPa, 6 MPa, 6.5 MPa), prestress types (unbonded prestress, bonded prestress), and beam types (segmental beam, monolithic beam). The results show that both segmental glue joint beams and monolithic beams exhibited typical brittle failure characteristics in the failure stage. The shear span ratio increased, the shear bearing capacity of the specimen decreased, and the deformation increased. The deformation of the specimen decreased when the prestress level increased. The bonded prestressed screw-thread bar improved the overall strength and stiffness of the segmental glue joint beam. The crack resistance of the monolithic beam was better than the crack resistance of the segmental glue joint beam, but the difference in shear bearing capacity between them was small. The test data were compared with the calculated values of shear bearing capacity of different formulas, and the results show that the calculated values of formulas of the American Association of State Highway and Transportation Officials (AASHTO (2003)) standard were in the best agreement with the test values. Based on the test results, the strain distribution and stress distribution of the specimens were further explored by combining the finite element method. The results show that cracks of different specimens would cross the glue joints. The yield strength of the prestressed screw-thread bar was not reached when the specimen was damaged. |
