Abstract: The urban bridge cluster health monitoring system is a complicated system featuring lots of parameters and hundreds of different types of sensors. The problems of data reliability of the system are the realistic ones that must be resolved in the engineering application. In this paper, in the light of the ideas of error control prevailing in the data communications, the basic considerations, models and mechanism for error control of bridge structure health monitoring system are put forward form the angle of the system and it can be therefore expected that the problems of two kinds of data failure pattern in the system of the tie arch bridge will be thoroughly resolved, the reliability of the system will be increased, and the false and miss warning ratio of the system will be accordingly effectively decreased.
Abstract: The purpose of this paper is to deal with identification of loads on suspenders. Values of the load at every moment were chose as identification parameters, and the objective function was established using measured data of responses and corresponding simulated ones. The vibration differential equation of suspenders was adopted to obtain the formula of relationship between the load and acceleration responses with superposition method. Furthermore, a regularization technique was applied in identification calculations to improve ill-posedness of the problem to be solved. With a tied arch bridge as the real example, the load on one of its suspenders was identified. Results of identification showed that the simulated data of acceleration response were almost identical to measured ones, which indicated validity of the proposed method.
Abstract: The bridge deflection measurement is an important component to the bridge examination and a important target to the security appraises. Using Slope sensor to test the Dynamic deflection is a good way for highway bridge deflection detection. In this paper, we develop a new slope sensor and new theory to fast calculate deflection from slope angle. It has been use to detect the dynamic deflections of songhuajiang bridge on Harbin-Changchuen highway when car cross at kinds of speed. The test result indicates: comparing with the measurement results of photoelectric deflection detection system, the dynamic deflection measurement results of slope sensors are much closed. Their deflection curves are also similar. The result also shows: Using our slope sensors to test highway bridge dynamic deflection can get precise results and can satisfy the highway bridge deflection testing request. It is also very easy to use. You can finish the testing easily and do not stop the traffic.
Abstract: Under inclement Qinghai-Tibet plateau environment, monitoring and analysis of railway subgrade deformation in plateau permafrost region has very important engineering significance for stability evaluation and safety management. In the paper, satellite interferometry was applied to measure subgrade deformation in the Beiluhe test site along the Qinghai-Tibet railway with gathered satellite interferometric SAR images. Based on the satellite-interferometry-derived data, the deformation characteristics of six points in different permafrost subgrades (the sliced rock embankment, the crushed rock embankment and railway bridge) along the Qinghai-Tibet railway were analyzed and compared. The analysis results show that settlement is the main behavior of railway subgrade deformation and the deformation amount of railway bridge is less than the sliced or the crushed rock embankment along the Qinghai-Tibet railway in permafrost regions.
Abstract: When the shield tunnel go through the bridge structure of high speed railway, it will affect the high speed railway bridge structure, thus influence to the bridge of track structure and ballastless track. Based on the Beijing subway tunnel go through the Beijing-Shanghai railway bridge section engineering examples, for the first time to shield under through the high speed railway caused the bridge pier settlements are analyzed. Combined with the actual monitoring data, the isolation pile during the period of construction bridge pier and Shield during through bridge pier during the period of settlement regularity of construction bridge pier, settlement regularity of Isolation pile as well as settlement regularity of the surface land are summarized analysis. During the construction of high-speed rail bridges and the soil to produce a certain degree of deformation, Shield Zone just above the soil settlement with a large deformation, both sides of the deformation gradually decreases, but the deformation is controlled. The use of the isolation pile reinforcement measures significantly reduced the influence by the Shield Construction and it can satisfy the requirement of high speed railway control standards
Abstract: It plays a very important role for the national economy and social security to gain bridge structure characteristic signal scientifically, to evaluate the bridge health condition and to guarantee long-term safe operation. The bridge health monitoring system is a major technique to settle those problems, which is in charge of working status inspection, health detection and alarm via field data, providing a solid safeguard for well-balanced operation of the bridge as well as the security of people’s life and property. This paper proposes a bridge health monitoring system based on wireless sensor network, which collects information of each mechanical part of the bridge. Sensor nodes form a smart measurement, and control network through self-organization, then transmit to the control center through network, by this way we can achieve real-time automatic remote monitoring on the bridge health.
Abstract: We have developed a remote-controlled visual inspection machine for bridge supports. This inspection machine adheres to concrete structures using two sets of suction cups, and ascends by alternating movements of the two sets of suction cups. Attached to the inspection machine is a CCD video camera. Video data of the condition of bridge supports is transmitted wirelessly to the operator. The visual inspection machine can ascend vertical concrete structures and then inspect bridge supports by moving horizontally. The maximum height the machine is capable of inspecting is limited by the length of the power cables as well as the weight. It will be able to inspect higher bridge supports when the weight of power cables can be reduced. The weight and the dimensions of the testing machine are about 17 kg and 84 cm by 72cm, respectively
Abstract: An increasing number of bridges have been built in earthquake zones, alonged with rapid development of high-speed railway. Their seismic behaviors attract researchers’ attention now. The steel shear keys as falling-off prevention measures have been used widely in 32m simply-supported box girder bridges on high-speed railways in China. To allow for transverse temperature movement, the shear keys are placed with a slight gap from the girders. However, out-of-phase vibrations between superstructures and substructures result in nonlinear eccentric pounding between bearing base and steel shear keys if the relative displacements exceed their initial gaps. The aim of this paper is to analyze the effect of eccentric pounding on elasto-plastic behavior of a simply-supported concrete box girder bridge under transverse earthquake, and evaluate the seismic performance of falling-off prevention measures. The effect of cushion block on seismic response has been studied. The results of the study indicate that a bridge column occur plastic deformation and suffer residual displacements due to eccentric pounding, and simple analysis in elastic range may result in nonconservative results. The lateral shear keys play a key role in limiting girder displacements. By setting hardwood blocks between steel shear keys and bearing base, the pounding forces can be appropriately reduced, and the lateral seismic performance of bridge can be effectively improved
Abstract: Fire effects cause one span of a frame underpass bridge in Harbin large area of different levels burning. Among them, some parts burned seriously; many adjacent beams turn black at bottom of roofs; parts of railings burned out of shape; parts decoration of side wall fractured, which blocked traffic towards Harbin. In order to make safety, repair on time, recovery traffic as soon as possible, satisfy the rules of original design and save money, this paper uses high strength non-shrinkage grouting material to repair stiffness of crack and damage concrete and carbon fiber to improve structure carrying capacity. Also, it uses middle support technique to reinforce the underpass bridge when repairing. Through a comparative analysis before and after reinforcement, paper confirms the feasibility and reliability of this repair design.
Abstract: Based on reliability theory, the application calculation method of Concrete Filled Steel Tube (CFST) arch bridge system reliability index is studied. Select the most unfavorable load distribution in working condition of maximum moment and deflection at the mid-span, from the angle of strain energy, calculated the weights of CFST arch ribs component. On the basis of the grading standards of reliability assessment of the existing bridge components and the critical structures, CFST arch bridge system reliability assessment grading standards are constructed. CFST arch bridges reliability index are evaluated from two aspects (the arch ribs and segment) in this article. As the CFST arch bridge locates in the marine environment, corrosion environment is the serious level of C5-M, steel pipe corrosion is the major diseases of CFST, arch rib which on the corrosion conditions were assessed. The results show that the method can effectively assess the situation of CFST arch bridge.