Browsing by Author "Wang, S. T."

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Displacement Coefficient Method for Bridge subjected to Pulse-Like Ground Motions
(2018-01-01)
Liu, K. Y.
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Wang, S. T.
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Hwang, C. C.
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Kuo, C. H.
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交大名義發表
This paper proposes the displacement coefficient, R-d, for bridge column subjected to near-fault earthquake. R-d is defined as a ratio between ultimate displacement and elastic displacement. 142 pulse-like ground motions are utilized to perform the nonlinear time history analysis with constant ductility from 1 to 6. This study investigates the R-d in four aspects, including (1) signal processing method, (2) orientation of the velocity, (3) hysteretic models, and (4) number of the ground motions. The analytical results are compared with the regulations specified in AASHTO 2011. For a structure with typical displacement ductility of 4, compared to the analytical results, the R-d in AASHTO 2011 is overestimated within the period of 0.5 second, and underestimated between 0.5 and 4 second. Therefore, the revised formulation of R-d is proposed, which could be suitable for the bridge considering the near-fault effect in Taiwan.
Unique pitch evolution in the Smectic-C-alpha(*) phase
(2007-08-17)
Liu, Z. Q.
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McCoy, B. K.
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Wang, S. T.
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Pindak, R.
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Caliebe, W.
Employing resonant x-ray diffraction, we observed unique pitch evolutions in the smectic-C-alpha* phase in mixtures of two antiferroelectric liquid crystals. Our results show that the pitch in this phase continuously evolves across 4 layers, contradicting a theoretical model that predicts that the smectic-C-FI2* phase intervenes in the smectic-C-alpha* phase. The phase sequences we found can be explained by another model that includes one type of long-range interaction among smectic layers.