Advanced Materials Research Vols. 243-249

Abstract: Firstly, the paper elaborates the general idea of the design of bridge forecasting and early-warning system. Based on the Compact RIO data acquisition terminal, the data acquisition system is established with data transforming through Industrial Ethernet and Internet. Finally, a remote safety evaluation center is developed with B/S frame, to process and analyze the collected data with the purpose of evaluating and forecasting the safety condition of the bridge. The application proposed by the paper can bring certain foresights in solving the bridge safety problems.

Abstract: Artificial neural networks (ANNs) have been widely applied to many bridge engineering problems and have demonstrated some degree of success. A review of the literature reveals that ANNs have been used successfully in member capacity prediction, reliability analysis, optimal design of structural systems, fatigue life prediction, construction control, material constitutive model , slope stability, bridge health monitoring. The objective of this paper is to provide a general view of some ANNs applications for solving some types of bridge engineering problems. A brief introduction to ANNs is given. Problems such as what is a neural network, how it works and what kind of advantages it has are discussed. After this, several applications in bridge engineering are presented.

Abstract: Based on the finite element theory, the computational model, one through concrete filled steel tube tied-arch bridge was established under the considerations of both geometrical non-linearity and material non-linearity. And using the ANSYS software to study the bridge's arch rib construction process and the overall stability after the complete construction, the results show that the full-bridge’s stability coefficient are larger than other concrete-filled steel tube arch bridge; the in-plane stiffness is larger than the out-plane stiffness, and the influence of material non-linearity on the stability is notable. The results provide a good reference for the similar bridge's design and construction.

Abstract: In this paper, the test of the indoor thermal environment for Tibetan traditional dwellings of Shangri-la in winter, that have tested indoor temperature and the temperature of house surface, and contrast to analysis tested parameters. The results of the test show climate characteristics in Shangri-la and variations of temperature effecting indoor thermal comfortable.

Abstract: Based on the investigation and detection of Dongji Bridge, a reinforced concrete (RC) T-beam bridge, the major diseases of the bridge was identified. The disease characteristics and rules are classified, the strength of the bridge was analyzed by finite element technology. Research is expected to provide scientific and rational basis for maintenance and reinforcement of Dongji bridge and same style bridges, and lay a foundation for further research work for RC T-beam bridges.

Abstract: By analyzing concrete crack on the roof caused by the pre-setting hole during the construction process of the pre-stressed concrete cast-in-situ box girder bridge, this paper, which uses segment integral analysis method by ANSYS finite element program, primarily takes into account different hole position and shapes. The result shows that different position and the shape of the pre-setting hole can be seemed as decisive factors in influencing stress near the hole. It can be concluded as: the pre-setting hole should set as far as possible from pre-stressed passageway and the pre-stressed rebar first, then the shapes of hole should use circular or take corner cut polygon. Ultimately, under the premise of normal used construction, it is considerable to strive as much as possible in narrowing down the dimension of the pre-setting hole.

Abstract: In this paper the transfer matrixes out plane of curved bridge are derivated.based on the FFT transform and the relationship between the quality and inertial force the point transfer matrix for vibration analysis is biult, and then establish the vibration transfer matrix and the total transfer matrix. Derivates the frequency domain transfer matrixes of single-span curved box bridges under uni-support or multi-support excitation, and offers a new method for seismic analysis of curved box bridges under multi-support excitation in frequency domain.

Abstract: Study on characters of suspension bridges free vibration is basic to analyze wind resistance, shock resistance, and other dynamic behaviors. Current studies are usually focused on earth-anchored suspension bridges. Compared with earth-anchored suspension bridges, self-anchored suspension bridges are anchored on the girder end which makes girder under the compression condition, cable longitudinal displacement can not be neglected, in addition, large ratio of rise to span leads to cable large tilt angle. Based on functional analysis method, it uses variation calculus to derive differential equation of two-tower and three-span continuous self-anchored suspension bridges free vibrations, taking into account cable tilt angle and cable longitudinal displacement. According to the simplified differential equation, it draws to a formula that can calculate self-anchored longitudinal and vertical vibration frequencies. Finally, two examples are carried out to check the formula’s reasonableness.

Abstract: The Train-Track-Bridge coupling vibration theory was applied to analyze the dynamic characteristics of a U-beam serviced in Chongqing Rail Transit Line 1 in China. According to the analysis, for the U-beam form of this opening cross-section, the traditional 3D beam element model can only reflect the first-order vibration mode, but neglect the coupled local flexure and torsion vibration characteristics; the 3D beam element model overestimates the lateral stiffness of the bridge, and underestimates it’s lateral vibration; the 3D plate element model is reasonable in dynamic analysis of opening cross-section structure; the vibration of U-beam dominates in the frequency range of f < 250, which is accurate and efficient to take into account this frequency range in the analysis of noise radiated by bridge structure.

Abstract: This paper used the OpenSees^[1] to simulate an externally prestressed composite beam, by contrasting the experimental results to explore the factors that affect the accuracy of the numerical simulation. The different numerical models are constituted with the different material constitutive models in this paper, with the different section fiber division and other factors. We can consider the method of a part of combination beam section which is connecting with shear rivets. The results show that the different concrete constitutive model and the hardening of the steel constitutive model are the important factors of the accuracy of model, and the Gaussian integration points have 3~5 are bitterly for the simulate mode. This study can provide a theoretical basis for the externally prestressed composite beam’s bending behavior of steel beam section’s numerical simulation with the fiber model.