Applied Mechanics and Materials Vols. 178-181

Abstract: Based on fuzzy analytic hierarchy process, The model of bridge health evaluation is established using the quantification relations between the bridge technical state evaluation grade and degree of membership function of bridge health evaluation, making use of the computed result of various index of degree of membership value and weight, obtains all levels of fuzzy evaluation collection. According to the maximum membership principles to evaluate the technical state grade of bridge structure the corresponding level, and with its result to instruct the decision-making of bridge maintenance and strengthening.

Abstract: The link slab of simple supported girder bridge deck was discussed in this paper. Based on “Gernal Code of design of Highway Bridges and Culverts(JTGD60-2004)” of China and linear elastic theory the continouse paving layer was analysized under the live load, temperature variation. The deformation and tensile stress formulations of link slab were given. The conclusion can provide theoretical basis for the design of building new bridge and strengthening and repairing old bridge.

Abstract: According to the characteristics and the development tendency of sea-crossing bridge construction, a concept of multi-purpose offshore operation platform for the construction of sea-crossing bridge is introduced in this paper. Meanwhile, the structure design plan and the features and advantages of the platform for sea-crossing bridge construction are listed in detail. The analysis shows that the multi-purpose offshore operation platform based on the modularization design concept could complete the tasks of sea-crossing bridge construction safely and efficiently. Due to the application of multi-purpose offshore operation platform, the construction cost of bridge should be reduced and the economy of project construction should be improved.

Abstract: Based on the secondary development of ANSYS, a through-type steel truss arch bridge is modeled, and the most unfavorable position of live load for each concerning location of the bridge is determined by using the influence lines program self-developed with parametric language. Linear elastic stability analysis of the whole bridge is firstly conducted, and followed by calculating the ultimate bearing capacity of the bridge with the consideration of geometrical and material nonlinearity of structure. By analyzing the buckling modes and safety coefficients of two types of stability problems, and comparing the linear elastic and nonlinear stability analysis results, the first type stability analysis, as a non-conservative method, is found to be suitable for ideal structures; the second stability analysis is found to be completely different from the first stability analysis, with different buckling mode and lower stability coefficient. Therefore, it can be concluded that the ultimate carrying capacity of structures should be determined based on the second stability analysis.

Abstract: In order to investigate the additional expansion force of continuous welded rails (CWR) on extra-long continuous bridges of high-speed railways, the integrative spatial finite element model of track-bridge-pier system is established with the nonlinear spring element simulating the longitudinal resistance between track and bridge. In this paper, the influences of several parameters to the additional expansion force of CWR are studied, including the different resistance models, the number of main spans, the arrangement of adjacent bridges as well as the pier’s longitudinal stiffness. Some conclusions are drawn through comparisons and analysis, which could provide valuable references for design and application of long-span continuous bridges on high-speed railways.

Abstract: Both ambient vibration testing and vehicle impact testing are carried out on a concrete multi-girder bridge. Ambient vibration testing is relatively easier to conduct and can provide detailed vibrating information of the structure. However vehicle impact testing is indispensable to obtain the impact factor of the traffic load. The measured vibration frequencies compare well to those of calculated values. This means that the finite element model may enable good predictions of the actual behavior of the bridge.

Abstract: In this paper,we want to obtain the research of virtual vehicle-birdge coupling system, a vehicle-bridge coupling model was established based on the multi-point Pseudo Excitation Method model, and then the simulation result was gained by ANSYS. First,a detailed multi-body dynamic model of the vehicle was established by using ADAMS/VIEW software package; secondly, a stochastic controller was designed for active suspension system and worked out by means of Matlab/Simulink, the proposed control algorithm was integrated with the multi-body dynamic vehicle model and the coupling system simulations could be performed repeatedly until a satisfactory controller was achieved, the system was compared with a conventional passive one. Simulation results showed that the proposed active suspension considerably improved both the ride and handling performance of the vehicle.

Abstract: The incremental launching construction method of super large-span arch-girder combination bridges is a new way in construction for late-model bridges. This article introduced the similarity model of a large-span arch-girder combination bridge based on similarity theory, in order to study the dangerous conditions during the construction of the real bridge. This article discussed the structure responses under one，two，three times dead-load additional weight and the wind load separately. The experiment result demonstrates that the experiment method could simulate the dangerous conditions during the real construction and check the stress effectively which can provide technical support for the construction of similar bridges.

Abstract: Using the Jianninxia Bridge as the experiment object, we set dynamic loading test on it, and did theoretical analysis on its natural vibration characteristics by using large-scale general finite-element software. After the comparative analysis between the collected datas and the theoretical analysis datas, we find that the measurement of the natural vibration frequency is greater than the theoretical analysis value; and the measured value of impact coefficient is less than the theoretical value; therefore, it indicates that this bridge’s actual structural rigidity is greater than its theoretical rigidity, but lack of the impact resistance.

Abstract: New requirement is claimed for the seismic design method of long-span railway bridges with the rapid development of high-speed railway construction in China during the last decade. However, the present design code of our country seems not keep pace with the engineering practice. The existing method, although embodying the philosophy of performance-based earthquake resistance design framework, in ‘the seismic design code of railway engineering’ is only applicable to those girder bridges with spans smaller than 150m. Therefore, the authors introduce the anti-seismic design measures of highway bridges from the Current China Specification to check the seismic safety of a long-span railway arch bridge as an applying example. Different seismic fortification criterions and property objects of the structural system and components are supplied in order to optimize the anti-seism performance of this bridge. The numerical results show that this kind of approach is helpful to improve the dynamical properties and seismic performances of large span railway bridges.