Applied Mechanics and Materials Vols. 178-181

Abstract: This article sets up two structural calculation models utilizing lumped mass method, and using MIDAS software: model A and model B. It proves that considering soil-pile-structure interaction has extremely vital significance in seismic response design of long-span cable-stayed bridge.

Abstract: With the development of long-span bridge engineering and increase of load on construction, the piles which socketed in rock more than 5 diameters have been used in some bridge engineering. Based on the technique of Anchored piles method, the static load tests of large diameter and deep socketed piles had been carried out in Qingdao Gulf Bridge. The bearing characteristics of large diameter pile were analyzed, including the load displacement curves of test pile; the axial force; the relationship between side friction and displacement and the sharing ratio of side resistance and end resistance. Finally, the test results were compared with specifications, The results showed that the bearing characteristic of deep socketed piles was as same as the friction piles in this area; from the results of test the side friction of pile could be estimated lower in strongly weathering breccia area while the friction in strong- weakly weathered breccia was relatively close to the value of exploration reports. At the bottom of the pile, because the relatively displacement of pile-rock was small, the pile side resistance is relatively small. It could be seen that the estimate of bearing capacity was less than the test result, and the pile foundation was safety enough.

Abstract: A new method for the natural frequency analysis of a beam with multiple transverse cracks has been carried out. The method is called reverse modal analysis in this paper. The strain energy density function is used to evaluate the additional flexibility produced due to the presence of crack. Based on the flexibility, a new stiffness matrix is deduced and subsequently that is used to calculate the natural frequencies and mode shapes of the cracked beam. It has been established that the crack depths and their positions have an important effect on its dynamic behavior. The analysis of the crack structure is done using finite element and experimental analysis. The results from numerical analysis are compared with the results from the experimental method for validation. The results are found to be in good agreement.

Abstract: The paper chose a three-span continuous steel box girder bridge with horizontal semicircular surface cracks as research object, and the cracks are non-through and unsymmetrical. Solving strain modal parameters of beams with cracks by means of the three-dimensional finite element theory, and applying continuous wavelet transform (CWT) to analyze the strain mode by Haar wavelet, then the position of the cracks could be identified by the maximum of wavelet coefficients. The validity of the method has been proved by numerical calculation and analysis. Some useful conclusions for continuous steel girders bridge have been drawn and it has been useful in surface flaw identification and diagnosis in structures.

Abstract: Static and dynamic test of 85m span half-through steel tube concrete truss arch were in. Follow contents were determined in the static test:control section deflection of steel tube concrete arch rib under test load;deck control section deflection and strain measuring in test load;deflection and strain measuring of suspender beam;strain test of suspender;crack observation of beam in loading. The deflection and strain measuring point of deck control section were on the beam. The content of dynamic load test :the measuring of impact coefficient、natural frequency and cable tension by frequency methods. Finally, operational situation of bridge was estimated.

Abstract: Prestressed concrete hollow slab bridge is widely applied in the highway bridge in our country, this paper shows that the crack moment decreases when loading time increases through the test of 30 m span real bridge under plate repeatedly loading, and get the calculation formula of crack moment again. The discipline between the crack width with loading process is also explored the conclusion is helpful to understand load cracking behavior under repeatedly loading and damage accumulation and performance of bridges.

Abstract: This paper investigates the thin-walled box girder bridges with large width-to-span ratios through both experimental and numerical studies. For the complexity of the bridge, different discrete models are presented in the analyzing of the longitudinal stiffened plate. In addition, a large-scale Plexiglas model is tested under different loading cases. The simplified simulation of the computation results compared well with the experimental results. It is illustrated that it is an effective method to predict properties of this kind of bridges.

Abstract: Based the hinged slab bridge theory and fundamental of structural mechanics, calculation formulas of load lateral distribution are deduced for hinged slab bridge with different rigidity between outside slabs and inside slabs, which make the hinged slab theory more perfect. Finally, a practical example is calculated and its results are compared with the results calculated by Equivalent Stiffness Method.

Abstract: Using ANSYS software to make a non-linear numerical simulation of the joints at A type super-high pier crotch ,and get the stress distribution of the crotch joints in different load combinations. The results can serve as theoretic reference for the joints design and the mechanical property analysis on this kind of structural components.

Abstract: One high piers and long-span bridge in mountainous area is designed as three-span which is 106+200+106 meters. The superstructure is pre-stressed concrete continuous rigid frame, and the sub-structure is hollow thin wall piers among which the highest is 167 meters. Under the background of this bridge, this paper mainly introduces the designing and construction methods of high piers and long-span continuous rigid frame bridge in canyon area, with the expectation to be served as reference to design the similar bridges in the future.