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2 Archives of Civil Engineering

2 2024

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Monitoring and control of steel truss arch bridge jacking construction

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Zheng X. , Guan D.

tom Vol. 70, nr 3

19--37

Through the real-time monitoring of the internal force, alignment and suspender force in the process of bridge jacking construction, the measured data and theoretical calculation values obtained from the monitoring are compared and analyzed, and it is found that the measured data are in good agreement with the theoretical calculation values. The results show that through the analysis of the real-time monitoring data of the jacking process of the bridge, the measured stress values of the main beam are within the range of –40.79 MPa ~25.13 MPa, and the measured stress of the main arch is within –40.33 MPa ~16.06 MPa, which does not exceed the allowable stress range of the steel in the jacking process, and the structure is safe. The measured elevation of the line is in good agreement with the theoretical elevation, and the deviation is mostly less than 5 mm, and the maximum deviation does not exceed the limit value of 8mm. The difference between the measured cable force and the designed cable force in the stage of removing the temporary pier is very small, which does not exceed ±5% and meets the requirements of the specification. The research in this paper can provide a reference for the jacking construction of similar bridges.

Causes and analysis of position offset of curvilinear continuous beam bridge

100%

Zheng X. , Guan D.

2024

tom Vol. 70, nr 2

561--578

This study investigates the problem of beam deflection in curved continuous beam bridges. Taking the D0-D6 spans of the Gongbin Road viaduct as a basis, the main factors influencing the deflection of curved beam bridges are analyzed. The Midas/Civil finite element simulation software is used to calculate and analyze the causes of transverse and longitudinal deflection in curved beam bridges. The results show that the main influencing factor for beam deflection during operation is the system temperature, which causes a displacement greater than the combined displacement caused by self-weight, construction stage, gradient load, vehicle load, and bearing settlement. Damages to expansion joints during operation change the boundary conditions of the beam, preventing longitudinal free expansion under temperature load, and increasing the transverse displacement to 2-3 times the normal working state of the expansion joint, resulting in beam deflection. In the design phase, the selection of curvature radius and fixed support displacement is also a major factor affecting deflection. The smaller the curvature radius, the greater the influence on transverse and longitudinal deflection of the beam. However, when the curvature radius R is greater than 400 m, the impact on beam deflection can be neglected. The closer the fixed support position is to the ends of the bridge, the higher the possibility of bearing detachment, ultimately leading to beam deflection.