Vibration displacements are one of the most significant indicators in the health monitoring and condition assessment of bridges in the life cycle. The traditional monitoring means, such as contact sensors, have relatively high-cost and limited points for displacement measurement of bridges. This paper proposes a low-cost and non-contact monocular vision system based on the KCF algorithm to accurately and timely identify the vibration displacement of bridges. A conversion method associated with a scale ratio was established to cope with the loss of depth information in images when a monocular camera is used to monitor multiple targets in different depths of the field. A series of shaking table tests on a two-column pier with energy dissipation beams were conducted to verify the feasibility, accuracy, effectiveness, and robustness of the KCF-based identification approach. The results showed that the vibration displacements of the column identified by the monocular vision system based on the KCF algorithm are almost consistent with the measurement results obtained by the laser displacement sensors. The peak displacement discrepancies between both measurement methods are within 6% for all cases with different shaking amplitudes and earthquake waves. The RMSE of the displacement histories between both measurement methods is very low. The corresponding frequency spectra contents identified by the monocular vision system based on the KCF algorithm match well with the measurement counterparts recorded from the laser displacement sensors.
Capacity and load balancing is an important prerequisite to ensure normal business. Based on the analysis of the multiple relationships between the capacity and load, and the impact mechanism of capacity load factor on the business benefits is discussed by the making use of resources benefits, opportunities benefits and risk benefits. It is concluded that a good state of load capacity ratio is very important to enterprises to improve business benefits. Finally an example of enterprise applications is provided.
This research is to assess the influences of the inertial mass from the girder on the dynamic characteristic, dynamic response, and structure-soil interaction of a pile-soil-pier subsystem in a scale-model of a cable-stayed bridge. Therefore, both connection configurations between the pile-soil-pier and girder, including the sliding and fixed connections, were designed to present various inertial mass from the superstructure delivered to the pile-soil-pier. The pile-soil-pier supported by a 3×3 pile-group in mixed soil placed in a shear box was tested using shaking tables. The dynamic characteristics, seismic responses, inertial interactions, and pile group effects of the pile-soil-pier between the sliding and fixed connections were analyzed under three input motions with different shaking amplitudes. These results showed that more inertial mass from the girder significantly increased the reinforcement strain and bending moment at the column bottom and pile top, displacement at the column top, inertial interaction effects, and pile group effects of the pile-soil-pier due to the sliding connection changing to the fixed connection. The inertial mass increment from the girder noticeably decreased the peak accelerations of the column of the pile-soil-pier when subjected to three input motions with different amplitudes. However, the inertial mass insignificantly affected the accelerations of the pile and free-soil. Therefore, the corresponding kinematic interaction effects were almost unaffected by the inertial mass. Additionally, the evident pile group effects were observed in the sliding and fixed connections between the pile-soil-pier and girder. 24 The numerical model could approximately reproduce the macroscopic seismic responses of the pile-soil-piers with sliding and fixed connections and capture the typical response variations induced by the connection configuration change.
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