Papers by Keyword: Dynamic Loading Test

Abstract: Full–scale dynamic testing of bridge structures can provide valuable information on the service behavior and performance of structures. With the growing interest in the structural condition of highway bridges, dynamic testing can be used as a tool for assessing the integrity of bridges. From the measured dynamic response, induced by instructed passing trucks, modal parameters (natural frequencies, mode shapes and modal damping values) and system parameters (stiffness, mass and damping matrices) are obtained. These identified parameters can then be used to characterize and monitor the service of the bridge structure in the future. Analytical models of the structure can also be validated using these parameters [1,2]. The paper presents a procedure for estimating the traffic load bearing capacity of the steel arch highway viaduct Bridge Structure 205 (DC1–9, 755 m) constructed on Highway D1 in Nord Slovakia (Fig. 1) over the natural hollow basin via dynamic tests of the viaduct structures.

Abstract: The cable-stayed bridge at the inner ring road in Prague in the Czech Republic was put into operation in 1997. In 2008 a crack was found in the bridge structure area where the end beam was connected with the upper deck of the box section and where the bridge expansion joint system was anchored. The basic objective of diagnostic works, which were started immediately after the finding of the crack, was obtaining the basis for bridge structure modifications, among other things, to prevent formation of similar damages in the future. A series of diagnostic methods was used for determination of the bridge actual state and the real static and dynamic bridge behavior. One of these methods was the dynamic load test. It was focused on an examination of the bridge forced vibration which was caused by dynamic effects of a usual traffic flow. An arrangement of the test was not quite usual because the experiment was concentrated on dynamic behaviour of bridge support areas especially. The abutment area, the pylon area and the area of a pillar with the bearing with a tensile structural element were observed on the investigated bridge. The dynamic load test was performed in two stages. The first stage was focused on investigation of bridge dynamic behaviour in original structural conditions and on obtaining the basis for design of bridge adjustments. The second stage was realized after bridge reconstruction in December 2012 and verified the effectiveness of bridge modifications.

Abstract: The paper is focused on the problems of the dynamic behaviour, failure and resistance of reinforced prestressed concrete railway sleepers, developed and verified continuously in the period of several last years. The results of dynamic loading tests are presented for the sleepers for both wide and narrow track gauge. The test results have been evaluated using the criteria for the acceptance based on the load corresponding to the prescribed crack width and the load at the moment of total fracture.

Abstract: In this paper the initial finite element model (IFEM) of the Jing Yue Yangtze River Highway Bridge was established and achieved the reasonable finished state of the bridge, which was the large-span, unequal height pylons and mixed beam cable-stayed bridge. The three-dimensional IFEM of the bridge accurately reflected its mechanical behavior under the static loading, and the structure physical parameters and stiffness of the IFEM didn’t need updating through the static loading test. The boundary condition parameters of the IFEM were updated through comparing the measured modal results of the dynamic loading test with the modal analysis results of the IFEM. The updated finite element model can truly reflect the dynamic characteristics of the bridge structure, and the model can be used as the benchmark finite element model, which can provide reliable calculation benchmark of the long term status assessment during the service stage.

Abstract: Nowadays, safety evaluation before bridge opening is increasingly emphasized in China. Bridge inspection is important to guarantee the safe operation of the bridge. In order to comprehensively assess the bearing capability and working conditions of Nanxi bridge of Lechangxia water complex, through static loading test and dynamic loading test, we measured the deformability and mechanical properties of bridge beams with different span-ratios and different forms. Basing on the results of dynamic/static loading test as well as the analysis of structure calculation, we conclude that the bearing capability and working state of the bridge are excellent. The knowledge gained from this study can be used as an evaluation reference in the quality evaluation of the same type of projects.

Abstract: The paper is dedicated to describing of experimental processes and experimental technique needed for realization of experimental tests of a bridge. The dynamic loading test was carried out on the monitored bridge. The time courses of bridge vertical displacements were registered. The power spectral densities of obtained records were used for determination of the basic natural frequency. The experimentally obtained results were compared with numerically obtained ones .

Abstract: By the detection of a three spans continuous beam bridge, the detection loading method and arrangement of measuring points are discussed, the static and dynamic detection results such as the deflection, stress and inherent vibration frequency are comparative analyzed with those of theoretical calculation. Results show that the bridge is safe under actual working condition, which provides the basis for normal operation and maintenance of the bridge.

Abstract: A multi-functional bridge bearing with built-in piezocomposite electricity generating element (PCGE) is being developed by our research team to respond to the growing demand of self-powered sensing devices for the monitoring of bridges by harvesting the energy produced by the traffic-induced vibrations. For the intended application, a multilayered piezoelectric PCGE structure composed of layers of piezoceramic, glass/epoxy, and carbon/epoxy, has been developed to improve the durability, output voltage and power of the piezoceramic. The output voltage of this PCGE can be used for real-time traffic monitoring like in bridge-weigh-in-motion systems and can eventually be exploited to generate the electricity needed for the lighting and functioning of other embedded sensors. This paper presents the results of the dynamic loading tests conducted on a prototype of the proposed multi-functional bridge bearing to enhance its design details and verify the accuracy of the measurement. The results show that the bearing provides reliable measurement for traffic monitoring and enable to conceive details for the improvement of the output voltage of the PCGE. Since bridge bearings, as indispensable devices transferring the loads and movements from the deck to the substructure and foundations of the bridge, are continuously subjected to traffic loads, the proposed bridge bearing appears to be a natural and economic solution that can be applied to existing or newly built bridges without modification of the conventional design while providing additional and valuable functions for the maintenance of the structure.

Abstract: The bearings of a bridge are indispensable structural members, which support the superstructure, transfer the loads of the superstructure to the substructure and, accommodate the horizontal and vertical motions of the superstructure caused by all types of loads like traffic. Such traffic loads induce the bridge to vibrate but this energy is wasted. Therefore, a piezocomposite electricity generating element (PCGE) has been introduced in the bearing to exploit effectively this vibrational energy. The bridge bearing with built-in PCGE was seen to be effective for measuring the traffic loads and, detecting eventual overloaded or overspeeding vehicles. In a will to optimize the amount of energy generated by this bearing, this study compares experimentally the amount of electricity produced by the PCGE with respect to its position in the bridge bearing through a series of dynamic loading tests to find out the position of the PCGE providing the most efficient electricity generation.

Abstract: This paper presents a new type of the electrical loading system with a large torque. Based on the characteristics of this system, the paper analyses the design of this system from some aspects: the hardware system structure, the host and the guest computer software system structure, method of restraining surplus torque. It is realized by torque and position hybrid control. Through dynamic and static loading test verification, this system has a large torque, high loading frequency, the higher loading precision to meet the testing needs of the domestic high-performance electrical loading system.