سال:1392 | دوره: | شماره: |تعداد مقالات:3

Bridge monitoring system via information technology is capable of providing more accurate knowledge of bridge performance characteristics than traditional strategies. This paper describes not only an integrated Internet monitoring system that consists of a stand-alone monitoring system (SMS) and a Web-based Internet monitoring system (IMS) for bridge maintenance but also its application to para-stressing bridge system as an intelligent structure. IMS, as a Web-based system, is capable of addressing the remote monitoring by introducing measuring information derived from SMS into the system through Internet or intranet connected by either PHS or LAN. Moreover, the key functions of IMS such as data management system, condition assessment, and decision making with the proposed system are also introduced in this paper. Another goal of this study is to establish the framework of a para-stressing bridge system which is an intelligent bridge by integrating the bridge monitoring information into the system to control the bridge performance automatically.

Shear wall has been considered as a major lateral load-resisting element in multistoried building located in wind- or earthquake-prone zone. The behavior of shear wall under various loading conditions has been the subject of intense research for the last few decades. The behavior of shear walls without openings is completely well understood and well documented in literature. The use of squat shear wall has been found in many low-rise buildings. On the other hand, squat shear walls may also be provided with openings due to the functional requirement such as placement of doors/windows in the building. The size and location of the opening play a significant role in the response of the shear wall. Even though it is intuitively known that the size of opening has significant effects on the behavior of a shear wall, it is desirable to know the limiting size of opening in the shear wall, beyond which the shear walls may fail or become unserviceable, especially when subjected to severe earthquake ground motions. In this study, the materially nonlinear dynamic response of the shear wall, with and without openings for different damping ratios, subjected to EL Centro earthquake has been captured. For dynamic analysis, constant acceleration Newmark b method of direct time integration has been used. From the study, it was observed that the presence of opening results in severe displacements and stresses on the shear wall and also results in stress concentration near the opening tip. Hence, the presence of damping has been considered to be vital for large opening under severe dynamic loading conditions.

The seismic design of most civil structures is usually accomplished using the response spectrum approach or simplified equivalent lateral force methods. However, some special tasks require the use of dynamic time history analyses. In the nuclear industry, for example, dynamic analyses are required in the design verification and seismic assessment of critical buildings and in the development of floor response spectra and free-field ground response spectra. The input motion for these analyses requires acceleration time series whose response spectrum matches a target design spectrum. This article revises the continuous wavelet transform (CWT) approach to generate spectrum-compatible records from the modification of acceleration time histories recorded in actual seismic events. The computational efficiency of the algorithm is increased greatly by performing the wavelet decomposition and details reconstruction via fast convolution using fast Fourier transforms. The new algorithm is evaluated using a typical design spectrum from the nuclear industry and different seed records.