Sinchuan Earthquake felt in Vietnam May 29, 2008
Posted by dionsiringo in Bridge Engineering, Earthquake, Jembatan Cable-stayed, Teknik Sipil.add a comment
The May 12 2008 Sinchuan earthquake was felt in northern area of Vietnam. Today we received the records from the instrumented Bai Chay Cable-Stayed in Ha Long Bay, about 1,154 km from the earthquake epicenter. The bridge experienced moderate shaking (acceleration RMS of 3.2 cm/s2) at the top of the 95m tower that caused 5 cm of displacement. The Bai-Chay Bridge is currently the world’s longest center span for the single-plan Cable Stayed Bridge (435 m). It is designed by the Japan Bridge & Structure Institute Inc, Pacific Consultants Int Tokyo, and constructed by Shimizu Corp and Sumitomo Mitsui Const. Co.Ltd. The bridge was just opened to traffic in December 2006
Seismic Monitoring of Cable-Stayed Bridge May 10, 2007
Posted by dionsiringo in Bridge Engineering, Earthquake, Jembatan Cable-stayed, Structural Monitoring.add a comment
Strong motion data acquired from instrumented bridges during seismic events provides an excellent opportunity to gain insight into the behaviour of bridges and performance of their components. Using system identification, modal parameters of bridges can be estimated and the performance during various level of earthquake can be studied. In this study dynamic behaviour of Yokohama-Bay Cable-Stayed Bridge is investigated using seismic response recorded from six earthquakes. Modal parameters of the structure are estimated using system realization of state–space model.
The realization method used here is based on the system realization using information matrix (SRIM), which makes use of the correlations between earthquake input and output data to identify the coefficient matrices of state–space model. Identification results from six earthquakes show that the system identification can be used to capture global behaviour of the bridge by estimating modal parameters and also to explain local behaviour of its component such as performance of link-bearing connections during earthquake.
Dynamic characteristics of a curved cable-stayed bridge April 29, 2007
Posted by dionsiringo in Bridge Engineering, Earthquake, Jembatan Cable-stayed, Structural Monitoring, Vibration.add a comment
An assessment of dynamic characteristics of the 455 m Katsushika–Harp curved cable-stayed bridge is presented. Dynamics characteristics such as natural frequencies, mode shapes and modal damping ratios are obtained from seismic response of the bridge by employing a time-domain multi-input multi-output (MIMO) system identification (SI) technique. The technique makes use of base motions and superstructure accelerations as pairs of inputs–outputs to realize the coefficients of state-space system matrices. The SI results indicate the occurrence of many closely spaced modal frequencies with spatially complicated mode shapes. Fourteen global modes in the ranges of 0.45–2.5 Hz were identified, in which the girder motion dominated most of the modes. The tower modes were associated with girder modes and were characterized by the lowly-damped motion. Using identification results from six earthquakes, the effects of earthquake amplitude on modal damping ratios were observed.
Living with and learning from earthquake April 29, 2007
Posted by dionsiringo in Disaster Mitigation, Earthquake, Indonesiana, opinion.add a comment
The two major earthquakes that have struck Indonesia recently caused damage beyond imagination. In 2004 the Aceh earthquake triggered the largest tsunami in modern history. Last month’s quake in Yogyakarta may be not as huge in magnitude as other great historic earthquakes, but the area affected was extensive. The casualties from these two disasters were staggering, and this should remind everyone how earthquake-prone Indonesia is.
Since the devastating San Francisco earthquake of 1906, anti-earthquake engineering techniques have continuously improved…
