Advanced Materials Research Vols. 163-167

Abstract: According to the 33 floors high building, blasting vibration monitoring had been carried on. The building, along Yunnan road tunnel of Qingdao Cross-harbor Tunnel Guide Line Project, has concrete frame structure. Monitoring data had been analyzed. Results showed that rules of vertical vibration velocity and main vibration frequency have similar relevance. Amplification effect of them was existed on the middle and top of the building. From the 2nd floor of downward ground to ground, the value of them suddenly decreased. Main vibration frequency is in the range of 101~102 order of magnitude.

Abstract: This paper demonstrated the feasibility of the adding roof on Ming Dynasty Castle in the Square City of the Ming Tomb. First, the structure composition of the existing ground in Square City and the wall of Ming Dynasty Castle was proved preliminary, through CT imaging of electromagnetic waves and on-site trench. Second by means of FEM, the stress and deformation of the wall load imposed were simulated. At last, the strain deformation of corridor in long period was monitored by grating sensors. It repeatedly demonstrated that the programs of adding roof on Ming Dynasty Castle can be achieved in the technology.

Abstract: Based on the integral synchronous lifting project of main span for Nanlin Bridge, this paper mainly studies the causes which lead to difference of non-uniform displacement in the key parts of the lifting bridge and its impact to construction safety and calculates the maximum limit value of displacement difference. A displacement sensor network is applied to monitor the difference of non-uniform displacement, a posture adjustment and control algorithm based on average displacement is proposed to ensure construction safety during the synchronous lifting. The numerical simulation of synchronous lifting of Nanlin Bridge is conducted to verify the validity of posture adjustment and control algorithm, this paper provides important theoretical basis for the promotion and application of these results in practical projects.

Abstract: When structural damage occurs, nonlinearity usually exists in damaged structures. So far, some progresses in the identification of nonlinearity in structures have been made. The extended Kalman filter (EKF) has been applied for the identification of nonlinear structural parameters. However, since the extended state vector contains both the state vector and the structural parameters, EKF approach can identify limited numbers of nonlinear structural parameters due to computational convergence difficulty. To overcome such problem, a two-stage Kalman estimator approach, which is not available in the previous literature, is proposed for the identification of nonlinear structural parameters. In the first stage, state vector of a nonlinear structure is considered as an implicit function of the nonlinear structural parameters, and the parametric vector is estimated directly based on the Kalman estimator. In the second stage, state vector of the nonlinear structure is updated by applying the Kalman estimator with the structural parameters being estimated in the first stage. Therefore, analytical recursive solutions for the structural nonlinear parameters and state vector are respectively derived and presented, by using the Kalman estimator method respectively. The proposed approach is straightforward. To demonstrate the accuracy and effectiveness of the proposed approach, numerical example of identifying the parameters of a 4-story nonlinear elastic Duffing-type shear-beam building is conducted. Simulation results show that the proposed approach is able to identify nonlinear structural systems.

Abstract: Settlement monitoring in the process of roadbed construction is one of the key technologies in the quality of passenger railway roadbed construction. By the specific circumstances of the roadbed project of passenger railway Tianjin to Qinhuangdao, outlines the meaning and content of the purpose of roadbed settlement monitoring, and describes the characteristics of a variety of settlement monitoring, function and layout of facilities in implementation, the requirements of technology, etc. Investigate and analyze the settlement monitoring information management based on construction control.

Abstract: In this paper, rail fastening of shanghai metro line1,2,3,4, the species distribution from a variety of fasteners and fastening performance comparisons of the two main aspects of the investigation. To mastered the main content of the use of Shanghai Metro rail fastening. Analysis of the popular types fastener of Shanghai subway such as type WJ-2 fastener, type DTIII fastener, type DTIII-2 fastener, type II elastic fastener. Track fastener in the actual use of shock absorber characteristics of the process. Come to Shanghai Metro rail fastening design and selection of line with actual needs, Shanghai Metro rail fastening series featured a wide variety and distinctive. Also pointed out that lack of adjustable fasteners, fastener corrosion, fastener and the lack of vibration reduction and performance degradation caused by a wide range of management and maintenance of complex and emphasize on the use of investigation and analysis of search problems, tracking the course of the development, research the causes and improve the conservation measures to maintain rail fastening methods Keti the safe operation of the subway has a crucial role in.

Abstract: Since piezoelectric materials exhibit strong temperature dependency. The change of temperature results in marked variation of the PZT transducer’s electric impedance signals, which may lead to misjudgment of the structural health condition. A experiment was implemented on smart aggregates with embedded PZT transducers under 35°C, 45°C and 55°C three working conditions, and found that the temperature had significant influence on the electric admittance signals of embedded PZT transducers. The peak magnitudes of the admittance curves changed and the curves shifted leftward. Then a temperature compensation technique was used to minimize the temperature effects.

Abstract: In this paper, FBG sensors are used to monitor and analyze the response of reinforced concrete frame-shear wall model in shaking table test in order to study the placement of sensors and the protection of the transmission lines. Based on the experiment data, the destructive mode and dynamic characteristics in earthquake are obtained through (by) analyzing the dynamic response of the structures. The experiment results show that using FBG is effective in monitoring the structures.

Abstract: As a new type of detection technique, BOTDR can conduct the distributed detection of pile foundation. Based on the characteristic that BOTDR is exposed to the effects of both temperature variations and deformation, the paper develops the temperature compensation sensor, and analyzes the effect of temperature variations upon the strain sensing during the distributed detection of pile foundation. Combined with the static load test of the bored pile in the engineering site, the paper examines the measured values of temperature variations in the surrounding environment during the detection of pile foundation, and finds out from the test result that the effect of the surrounding temperature upon the pile strain is negligible. Through analyzing the pile shaft bearing capacity of the test pile under both vertical loads and horizontal loads, this paper deduces the theoretical formulae for the axial force, the side resistance, the compression, together with the deflection of the pile shaft, and then applies these calculating formulae to the practical engineering project. From the comparative analysis of the calculated results and the measured results, it can be found that these two results are almost the same, which finally proves that the distributed detection technique of BOTDR can effectively detect the pile shaft deformation under loads, and can provide the precise detection of pile foundation.

Abstract: It has been proved that Multi-layer network computing can solve the nonlinear separable problem, but the problem which the hidden layer makes the learning more difficult limits the development of multi-layer network.Back-propagation (BP) algorithm solve this problem and promote multi-network research to regain attention. In this paper, A new method which dynamic matrix control method based on neural network is found. Its essence is that the resulting prediction signal is produced by the manner which regards neural network model as prediction model, and the predictive control of nonlinear systems would be realized by the control law which using the receding optimization algorithm. Neural network Selects the BP neural network which possess a good nonlinear function approximation capability.Aiming at dongping tunnel surface deformation prediction, the article adopt BP Neural Network to train the system basing on the given data. It shows the hiding neural node is close to precision; predictive value in good agreement with measured values, and to some extent be able to guide the construction.