Applied Mechanics and Materials Vols. 744-746

Abstract: A method for bridge structural parameter identification using field measured static influence lines with respect to various types of measurement is presented. Static test data on displacement, tilts and strains are quantified by means of influence lines to estimate global and local, sensitive and insensitive parameters of any model form of structure. A quadratic performance error function to be minimized was established with interpolation or fitting procedures. An analytical example of a simply supported beam is employed for demonstration purpose. A numerical example of plane stress is presented and local and insensitive parameters are successfully and accurately estimated. Results of the example suggest that despite no competitive advantage in estimating the sensitive parameters with integrative measurement, it is an essential point to the successful identification of insensitive parameters by making a judicious selection of integrative measurement.

Abstract: In recent years, traffic lines are rapidly thrusting into the hilly regions^[1]. It’s not hard to list such cases that bridges have been damaged by mud-rock flow. In this paper, it is studied that the dynamic response of the solid T-pier to mud-rock flow. a finite element method is applied to analyse the effects of the stress and strain of an T-pier under the impact action of mud-rock flow with different velocity.

Abstract: In order to appraise the safety and reliability of bridges effectively, the comprehensive evaluation model based on analytic hierarchy process was established. The weight of evaluation index was calculated by using the model, and each evaluation index was given score by experts according to actual circumstances, and, on this basis, safety level of the bridge was obtained. And, afterwards, the model was applied to an engineering example for Huangjiaba Bridge. The results show that the evaluation level of bridge safety is third-level, with serious problems existing in this practical example, and the corresponding measures are proposed, which can provide scientific reference for bridge safety management.

Abstract: The thermal displacement of a large scale footbridge is investigated in this study through numerical simulation. With appropriate assumption, the temperature field of the footbridge is simplified and divided into several components. Fine finite element models are constructed for the deck plate, bridge section, and bridge tower to calculate the structural thermal effects. The made observations indicate that the thermal deformation of the bridge tower is much larger than that of the deck due to the cable sag under temperature increase.

Abstract: In combination with the composite material technology, add the glass fiber grid into gussasphalt deck pavement system to form glass fiber grid reinforced gussasphalt. Analysis shows that adding the grid can increase the bending performance. Three point bending test was did to do verification and results were indicate that glass fiber grid can improve the anti-bending strength and anti-bending strain in high temperature.

Abstract: A detailed FE model for analysis of overturning of concrete box-girder bridge with single-column piers was developed and the failure process was discussed in the presented paper. The result shows that the reason for overturning failure is the non-uniform compression deformation of the loading-side bearing caused by the eccentric external load, which then leads to a large rotating angel of supper structure. Once the friction force between Teflon plate and steel plate in the bearing cannot carry the diagonal component caused by the gravity load and external load, the sliding failure occurs. Based on the simplified mechanical analysis, the condition that bridge overturning occurs is that the tangent value of the rotating angle of box girder is greater than the friction coefficient between Teflon plate and steel plate in rubber bearing.

Abstract: The reasonable cable force is the key factor for the safe use of cable-stayed bridge. This paper adopts the method of continuous beam on rigid supports, zero displacement method and the internal force balanced method for cable force estimation of completion stage. The estimation value of cable force is determined by comprehensive considering various methods. With the estimate value as the initial cable force of feasible domain method, conducting the cable force optimization. Comparing the optimization with estimation value and conducting analysis calculation to ensure the rational completion status. Referring a cable-stayed bridge’s example, and conducting the estimation and optimization of cable force, the calculated results meet the requirements. The results show that the method is effective and practical.

Abstract: Synchronous gravel water-proof adhesive layer has many advantages, and is widely used to bridge deck pavement. Though the material of synchronous gravel water-proof adhesive layer has high temperature sensitivity, it needs more research that whether this construction can well adapt to seasonal frozen region. Used UTM-100 and self-design testing machine, we tested and analysis the key parameters of the water-proof adhesive layer about SBS nature-changing pitch crushed stones, rubber-asphalt synchronous gravel and high-viscosity asphalt synchronous gravel. Firstly, based on result of core testing under normal temperature, I determined the best mix-proportion for three materials, and tested their shear, tensile strength, deformation performance under different temperature and humidity.

Abstract: Longitudinal crack in bottom flange is one of the most common defects in concrete box girder bridges. This paper focuses on the influence of the longitudinal cracks on the mechanical properties of box girder using numerical method. Smear crack model and strain softening model was employed to simulate cracking process. Parameter analysis was also carried out to study the effect of length, crack depth and amounts of cracks in bottom flange. The results indicate longitudinal cracks in one span have a significant effect on the transverse stress and deflection, but have little effect on the other spans. The negative effects of longitudinal cracks increase with the crack length and depth. When the crack length is up to 10% of the girder span, the deflection of the span amplifies to 13%. Compared with the length and depth, the amounts of cracks don’t have much influence on the deformation of girder but affect stress.

Abstract: The key technology for widen continuous hollowcore slab bridge with long unit is improved. Taking Taiping flyover in Guangshen highway as an engineering background, the principles of splice joint are given, extension schemes are analyzed and compared in this paper. A reasonable scheme is decided finally and a 3D finite element model is established to check if the structure is satisfied with the requirement form the codes. After the extension project is finished, a local monitoring is carried out, including monitoring for stress and settlement. Both the calculated result and the test result are in acceptable range and satisfied with current codes. The research shows, the rigid joint structure adapted in this paper is reasonable.