No abstract

Based on the real construction technology, process and environment of Yuquanxi Bridge, the finite element method was applied in the research to make sure the crack mechanism and find out the impact of improper construction procedure on cracks of Block No.0. By comparing the numerical results with actual cracks condition, the impact of improper construction procedure on cracks of Block No.0 is uncovered clearly and it proves that to master of correct construction procedures and methodology is of great importance in construction a bridge.

Cracks on the Joint Part between Pier and Girder, namely Block NO.0 in the construction process, has become one of the major diseases of continuous rigid-frame bridges. Based on the real construction technology, process and environment of Yuquanxi Bridge, the uneven distribution of stress caused by various factors is precisely analyzed by ANSYS. The shrinkage difference of concrete, the excessive hydration heat, and the sunshine temperature difference is accurately simulated respectively. By comparing the numerical results with actual cracks condition, the results prove that the theoretical analyse is accord with the actual situation, and the real reason of cracks on Block No.0 of Yuquanxi Bridge is uncovered. This study is of great practical value in preventing cracks and improving bridge construction technology.

During the research of local stress distribution of polyline pretensioned beams by 3-D nonlinear finite element method, a problem of curve prestressed reinforcement simulation is discovered. If the line of prestressed reinforcement is curve, the calculated result of local stress distribution is greatly affected by element size, because of the tectonic stress concentration by the coupling between the linear element and body element. Then, the validity and applicability of the model couldn't be judged. To eliminate the harmful effect, the curve prestressed reinforcement is determined to simulate by body element. The result shows that it will solve the problem thoroughly, and the calculated result is truthful and reliable. This research presents a new thought and method about the local stress analysis of the prestressed concrete structure.

Considering the slender property, the reinforcement is always simulated by linear element in conventional FEA of concrete structures. But to the curve prestressed reinforcement, it will lead to the problem that the calculated result of local stress distribution is greatly affected by element size, because of the tectonic stress concentration by the coupling between the linear element and body element. To eliminate the harmful effect, the curve prestressed reinforcement can be simulated by body element. The result shows that it will solve the problem thoroughly, and the calculated result is truthful and reliable. Certainly, as a kind of slender component, there are some key point must be recognized when the curve prestressed reinforcement is simulated by body element. To reflect the mechanical properties of prestressed reinforcement and solve the key challenges of modeling, some key techniques of modeling and some special notices about element property settings are discussed detailedly in this paper.