Abstract

Assembly construction is the main feature of industrialized bridges, and π-shaped section steel–concrete composites that are continuously rigid have been widely used in engineering fields in recent years; however, their dynamic responses and corresponding impact coefficients in positive and negative moment regions need to be further studied. First, considering the interface slip model, we established a finite element model for the π-shaped continuous region section of the steel–concrete composite on the Sutai Expressway Tongfu No. 3 viaduct. Second, the bridge deck unevenness parameters were generated by preparing a MATLAB program with random calculations and were added to the bridge deck as the excitation load along with the vehicle load. Such parameters are defined on the basis of considering the vertical degrees of freedom of the four wheels and of one vehicle rigid body. Finally, we analyzed the displacement or stress impact coefficients as the dynamic response index of the bridge by adjusting the vehicle travel speeds, vehicle weights, interface slip stiffness values, and deck unevenness values. The results show that the change in vehicle travel speed and the change in vehicle load weight have some influence on the change in the dynamic effect of the combined beam, but this change is not significant. Moreover, the unevenness and interface slip strength changes have a large effect on the dynamic effect of the combination beam, which can significantly change the impact coefficient of the combination beam bridge. The worse the unevenness of the bridge deck is, the lower the grade of interface slip for the steel–concrete composite bridges and the higher the impact coefficient. We calculated the recommended impact coefficient values of the steel–concrete composite bridge based on the specifications for various countries, and they range from 1.16 to 1.4; such values are similar to the finite element calculation results.

Highlights

  • This paper first studies the dynamic performance of the bridge structure in the moment including the middle ofmiddle the sideofspan, the middle of middle the second sidesecond span, positive zone, moment zone, including the the side span, the of the and middle of middle the middle span at different positions

  • For a steel–concrete composite continuous rigid bridge with a span diameter of 5×30 m, considering the vertical load of the driving car, the side pivot section and the middle pivot section [39] were loaded with a negative bending moment while the car was driving across the bridge, and this loading situation led to tension at the upper edge and compression at the lower edge of the combination girder section

  • The maximum strain values at the secondary edge support point and the middle support point of the steel–concrete composite continuous rigid bridge was extracted, and the impact coefficients corresponding to different locations and different bridge deck unevenness were calculated

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Summary

Introduction

Assembled steel–concrete composite continuous rigid [7] beams usually consist of independently fabricated steel main girders with concrete deck slabs. A steel–concrete composite continuous rigid beam is installed first, forming a continuous steel girder before installing the precast concrete deck slab. The construction sequence of first installing steel girders and concrete deck slabs will eventually lead to inefficient and inconvenient construction of steel–concrete composite continuous rigid bridge assemblies. Su Qingtian proposed a π-shaped steel plate girder formed by connecting two I-beams with crossbeams instead of with a single I-beam, and the single group of beams was lifted onto the support as a whole after the construction was completed. Dynamic performance research on search on steel–concrete composite continuous rigid bridges is especially important.

Finite
Dynamic Performance of the Positive Moment Zones
Position
Stress
Dynamic Performance of the Negative Moment Zones
Discussions
Findings
Conclusions
Full Text
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