Key Engineering Materials Vol. 619

Abstract: Structural Health Monitoring is becoming an increasingly common tool to obtain the long-term performance of infrastructures and buildings. Many structural health monitoring systems were developed and applied to different bridges in the world. However, very little is known on the applications in extreme cold environment. Fu Sui Bridge, a 1070 m variable cross-section continuous box-girder bridge, is located in the coldest province -- Heilongjiang province, China. In order to monitor the static and dynamic responses of the bridge under the traffic and environmental variation, a long-term continuous monitoring system was designed and installed on Fu Sui Bridge in April 2012. A hydrostatic leveling system was used to measure the displacement and fiber Bragg grating sensors were used to measure strain, acceleration and temperature. Moreover, other necessary components including data acquisition and transmission, data calculation and analysis software are also described. Summer and winter monitoring data are also presented. This paper focuses on: (1) the design and installation of the long-term continuous monitoring system hardware and (2) the operating pattern and function of the automatic monitoring system. After more than one year successful conducting, the system has provided a large amount of data records for daily management and research of the bridge. This system can be applied to extremely cold region.

Abstract: This article briefly reviews the two methods of finite element model (FEM) updating, such as direct matrix methods and the sensitivity-based model updating methods. In addition, the problem in bridge structure model updating often needs to solve large-scale ill-posed linear systems. Therefore, two regularization methods of Tikhonov and TSVD were introduced. Meanwhile, for these systems, it is proposed that the application of the two kinds of regularization method to solve the problem which the test data contaminated by noise may rarely lead to a physically meaningful updated model.

Abstract: This paper makes a comparison between computer and hand computation of joint core area according to an example of typical engineering. Firstly, author summarized the common problems and erroneous judgments which are likely to happen in the software calculation of joint core in engineering design, and then analyzed the causes to these problems, and provided hand calculation solutions to related problems according to standard formulas. Author analyzed and proved that the reinforcement calculation of joint core area for frame structure calculation is not only necessary, but also can conveniently solve the coordination problems in the related terms of “Concrete Structure Design Norm”, “Earthquake Resistant Design Code” and “Concrete Structure Engineering Operation Standard”, and is also the supplement for the uncovered parts of computer calculation.

Abstract: With the application of computer technology in civil engineering more and more widely, it is important to find new methods suitable for computer programming to solve the engineering problems. In this paper, a new method based on differential equation group is introduced to analyze statically determinate beam and rigid frame. Firstly, the division method of member system is given and differential equation group is established. Secondly, the determination of boundary conditions is discussed in different situations. And the approximate analytical solution of internal force of statically determinate beam and rigid frame is obtained. At last, two calculating examples are given. The result shows that this method is easy to be programmed and suitable for application in engineering and teaching.

Abstract: This paper aims at discussing and summarizing the methods for dealing with the massive monitoring data obtained from the structural health monitoring system of bridges. Firstly, some methods related to the 'big data' issue were introduced such as dynamic fingerprint analysis, model updating method, artificial neural network, genetic algorithm, wavelet analysis etc,. Secondly, this study focused on the basic idea, research situation and existing problems of above methods. Finally, the research emphasis of the methods for dealing with massive data was proposed.

Abstract: This paper summarized and evaluated the girder construction methods of self-anchored suspension bridge, pointed out that the main beam linear would have a local depression between the largest span temporary pier when the steel-concrete composite beams were constructed by the incremental launching construction method, even if the main beam were withstand uniform bar-forces, moreover, the pre-camber curve of the main-girder could not arranged as a circle curve or quadratic parabola within the entire span. In view of this, the entire construction process of a self-anchored suspension bridge was analyzed by the finite element method, The results showed that the section property changes of the steel-concrete composite beam were the nature reason of the local depression on the main beam linear; The completed main beam was simplified into a three-span continuous beam which suffered vertical uniform distributing load and horizontal forces at the two ends, and the simplified formulas of calculating the vertical displacement of each span were derived by the force method; The numerical example showed that, the proposed simplified formulas could effectively solve the affection by the section property changes, accurately predicted the main beam cumulative vertical displacement, and the calculation accuracy could meet the engineering requirements, the conclusions of this paper had a strong guiding significance and reference value on the camber design and construction of the bridge wth the similar structural type.

Abstract: This paper reviewed and discussed some key issues of structural health monitoring (SHM) of long-span bridges. Firstly, the current situation of the application of structural health monitoring technique to long-span bridges was summarized in detail. Secondly, starting from the purpose of ensuring the safety of operational bridges, the composition characteristics and functional requirements of structural health monitoring system of long-span bridges were discussed, which include the global design principles of health monitoring system and the design approaches for each subsystem. Finally, some challenges of the technique of SHM were proposed including structural force analysis, the principles of optimized distribution of sensors and the assessment methods of structural damages of bridges etc,.

Abstract: To address the drawback of comfort evaluation on Highway Bridges due to moving vehicular loads, a large-span continuous girder bridge, namely Yilan Songhua River Highway Bridge, is studied in detail. The pedestrians comfort and riding comfort of the selected bridge under both single-vehicle and multi-vehicle are analyzed by our computer programs VBCVA (vehicle-bridge coupled vibration analysis) which is based on modal synthesis method and VCE (vibration comfort evaluation) which is based on existing common evaluation criteria. The peak accelerations of vehicles and the bridge are significantly influenced by the increase in bridge surface roughness as speed increases. Pedestrians acceleration induced by truck is larger than that induced by car. Except at the abutment span where the resonance speed is lower than other spans, the comfort of pedestrians at different locations of the mid-span are practically the same for various speeds. The riding comfort influenced by the truck on adjacent lane is dependent on the relative value between the dynamic response of the bridge and its roughness. For continuous girder bridges, because of the smaller dynamic response induced by the truck on adjacent lane compared to that induced by the roughness of the lane itself, the influence between adjacent lanes can be ignored. Finally, it is shown that the pedestrian comfort and riding comfort of the newly built Yilan Songhua River Bridge could meet the existing requirements in normal operation.

Abstract: A thorough research was made on the commonly encountered damages in cable members of the concrete filled steel tubular (CFST) arch bridge and their detection methods. Four main types of damages, including cable protection measure damage, anchor system damage, cable body damage and other damage types were discovered after a comprehensive study of the cable members on some existing CFST arch bridges and the related references. A focus has been placed to analysis each types of damages individually, based on their characteristics, failure mechanism and destructive effects. Furthermore, the detection methods for the damages in cable members were introduced and evaluated elaborately. Therefore, this study provides a valuable reference for the daily maintenance and maintenance specification establish for cable members of CFST arch bridge under different scenarios.