Applied Mechanics and Materials Vols. 351-352

Abstract: This paper demonstrated the importance of bolt tightening in engineering application, and given the injector clamp tightening of engine model. We given the calculation method of snug torque and angle of torque-angle tightening of bolt, and this calculation method of bolt tightening has an important control function. In addition, the torque and angle Adjustment method was given. We introduced the Experimental Study. Finally, the injector clamp tightening bolt M8×1 of JX4D30X engine as an example, Examples proved that the results of theoretical calculation and experimental study uniform. These studies have not been involved in other papers.

Abstract: Structural concrete strength rapid detection methods were analyzed, which mainly include Rebound Method, Ultrasonic-rebound Combined Method, Dirlled Core Method, Pull-Out Method. Technical characteristics, advantages and disadvantages of each method were compared and analyzed. Application of each method was analyzed. Based on current detection technical specification, ultrasonic-rebound combined method for testing concrete strength was analyzed. Actual concrete bridge as a platform for a comparative test, ultrasonic-rebound combined method test was carried out. Problems were put forward and recommendation was made through discussion.

Abstract: Large span self-anchored suspension bridges which are located in the strong earthquake zone often have no sufficient anti-seismic capacity, especially the bridge pylon. Therefore, seismic response control is necessary. This paper studies the lateral damping control effects of one large-span self-anchored suspension bridge with tuned mass damper (TMD). Using a spatial dynamic analysis finite element mode, the seismic responses are calculated out. Seismic response analysis results show that a large lateral displacement appeared at the pylon top under the lateral seismic action and the moment peak at the pylon bottom is nearly reaching its equivalent yield moment gotten by moment-curvature curve, which would be resulted in a high risk of collapse of self-anchored suspension bridge under lateral earthquake action. Therefore, one TMD is considered to be applied on the pylon top of the self-anchored suspension bridge to reduce the seismic response. The simulation result shows that the TMD can provide remarkable effect on seismic response control of the pylon. The control efficiency of TMD can be up to 23.4%. The moment at the pylon bottom and the displacement at the pylon top both decrease obviously. The parameter analyses of TMD are also performed to get the best design parameter. The research results can be used as the reference of seismic response control or anti-seismic design for the same type of bridge.

Abstract: Bridge health monitoring system (BHMS) is a package of technologies for structural monitoring, control, maintenance and management. Making use of the fusion of technologies from different disciplines, such as sensing, communication, signal processing, system identification, etc., the system is empowered to simultaneously get all kinds of information which reflect the safety conditions of bridge structure, and provide scientific proof for the analysis of bridge health. The assessment method is the core of the BHMS. In the conventional assessment procedure, there is significant influence of subjective factors involved. A feasibility study on the use of fuzzy comprehensive evaluation method in the bridge condition assessment is presented in this paper. The applications of fuzzy mathematics in condition assessment of bridges were discussed. Based on the research of present methods, analytical hierarchy process and fuzzy mathematics were integrated and applied in condition assessment of the project of main roads bridge Online Safety Monitoring Management System in Hangzhou (Phase II), a web-based urban bridge cluster monitoring system have been established. From a continuous beam bridge case study, it is observed that the fuzzy comprehensive evaluation method is capable of simulating the bridge condition evaluation process and has a good application.

Abstract: Material properties, calculation models and parameters are the main factors affect the simulation results of concrete face rockfill dams. According to the Baixi project, a 3D numerical model was built including the concrete face, filled rock, rock foundation and peripheral joint. Then, based on the deformation monitoring data during the construction and water storage period, the Duncan E-B model parameters were back analyzed. Finally, the sedimentation of dams, stress and strain of concrete face was simulated, and the actual working performance of concrete face and filled rock was studied.

Abstract: Arch dam has gradually evolved as one of dam type as main large-scale hydraulic project, dam deformation prediction is an important part of dam safety monitoring, and it is difficult to forecast because of the complicated nonlinear characteristics of the monitoring data. Support Vector Machine (SVM) could solve the small sample, nonlinear high dimension problem due to the excellent generalization ability, and hence it has been widely used in the forecast of arch dam deformation. However, the forecast results considerably depend on the choice of SVM model parameters. In this paper, Particle Swarm Optimization (PSO), which has the characteristic of fast global optimization, was applied to optimize the parameters in SVM, and then the dam deformation prediction model based on PSO-SVM could be established. The model is applied to a certain arch dam foundation prediction. The accuracy of this employed approach was examined by comparing it with multiple regression method. In a word, the experimental results indicate that the proposed method based on PSO-SVM can be used in arch dam deformation prediction.

Abstract: Internal defect of mortar finishing layer was detected using thermal infrared imager. The main object was to study variable characteristics of surface temperature on internal defect of mortar finishing layer heated by external heating source. The distribution and variation law of surface temperature on mortar finishing with time and space were obtained,and the influences of thickness,area and embedded depth of internal defect on image quality were analyzed. The test results show that the thicker, bigger and shallower internal defect is more easily detected. The surface mortar temperatures of internal defect is maximum temperature point of approximate symmetry along the width direction. Based on the test results, the prediction model of dimension of internal defect was established through statistical analysis technique, which can provide a reference for the related follow-up study and practical project application.

Abstract: This paper introduced the stepwise regression analysis principle, grey correlation analysis and Kalman filter. Aiming at the situation of more impact factors on a certain dam deformation, a new algorithm for Kalman filter based on grey correlation analysis is given. It takes the horizontal deformation of a certain dam for example, through the grey correlation analysis to discuss the correlation degree of various impact factors and establish grey correlation Kalman filter model, and carry out comparison analysis of stepwise regression model. The results show that both two kinds of models have a better precision, but the grey relational Kalman filter presents higher synthesis accuracy and can provide more accurate prediction results.

Abstract: A new method of measurement of the cable force in cable-stayed bridge model test is introduced. Pressure ring sensor is used as the main component in this method and the tension of the stay cables can be measured real-time and in time. It is vertified that this method is exact and credible by model test and can be used in actual cable-stayed bridge. The static measurements for the test model are conducted. The testing results are compared with the numerical results of finite element model developed for the test model. A platform is established for the future researchs.

Abstract: The rebar-planting anchoring , based on the development of the technology in the field of architecture both at home and abroad and applications, and combining with the mechanics performance of planting-bar, , technical requirement and the anchoring depth of the relevant specification, for the imperfections in the application of this new technology put forward the corresponding improvement suggestions.