Assessment of the effects of local geology using long-period microtremors and the 1989 Loma Prieta earthquake motions
Explore the source record for details and available documents.
Geology topics
Publications and source records attributed to Mehmet Çelebi.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The March 13, 1992 Ms = 6.8 Erzincan earthquake in Turkey is highlighted here. The epicenter of this earthquake was located 7.7 km from the eastern end of the North Anatolian fault. The strong motions recorded in Erzincan had peak ground accelerations of approximately 0.5 g, accompanied by a pulse of 2 seconds. The duration of the earthquake was 7 seconds. This earthquake caused collapse of about 150 buildings--mainly to 4-5-story reinforced, concrete-framed buildings with infill walls. This damage, which is discussed, can be attributed to non-compliance with seismic codes.
A method to estimate the center of rigidity of buildings by using vibration recordings is presented. The method is based on the criterion that the coherence of translational motions with the rotational motion is minimum at the center of rigidity. Since the coherence is a function of frequency, a gross but frequency-independent measure of the coherency is defined as the integral of the coherence function over the frequency. The center of rigidity is determined by minimizing this integral. The formulation is given for two-dimensional motions. Two examples are presented for the method; a rectangular building with ambient-vibration recordings, and a triangular building with earthquake-vibration recordings. Although the examples given are for buildings, the method can be applied to any structure with two-dimensional motions.
Explore the source record for details and available documents.
Records obtained from the West Valley College Gymnasium in Saratoga, California during the 1984 Morgan Hill earthquake are used to study the dynamic behavior of the overall gymnasium as well as its flexible disaphragm. The ground-level motions recorded in the two orthogonal axes of the structure differ considerably in peak acceleration and amplify by approximately 1.5 times at the roof edges and by 4-5 times at the center of the diaphragm. The diaphragm responds with a frequency of approximately 4 Hz in both orthogonal axes. A simple finite-element model is used to match the fundamental frequency of the diaphragm with that from the records. Using this model and the ground-level motions as input, the diaphragm center displacements are calculated by varying the structural damping. Best comparisons are obtained for 5% damping. These results are discussed in terms of the code provisions.
No abstract available.
Explore the source record for details and available documents.
No abstract available.
No abstract available.
No abstract available.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
No abstract available.
Explore the source record for details and available documents.
No abstract available.