Based on the station velocity data obtained from Fujian coastal GPS network and Taiwan-Luzon GPS network and the data obtained from IGS permanent stations commonly used in the data processing of both networks, the uni...Based on the station velocity data obtained from Fujian coastal GPS network and Taiwan-Luzon GPS network and the data obtained from IGS permanent stations commonly used in the data processing of both networks, the uniformity of reference frames and velocity fields of both GPS networks is realized. It has been discovered from the analysis on the velocity field in Taiwan and its coastal areas that the horizontal crustal movements in the coastal area of Fujian, Taiwan Strait and the northern part of Taiwan Island are fully consistent. The movement direction is around 26.0E by S and the rate is about 39 mm/a. The opposite variation occurs in the coastal mountain area in the eastern part of Taiwan Island with the movement direction of 30.0N by W and the movement rate of about 33.3 mm/a. In the southern end of Taiwan Island, the movement direction is 50.0S by W and the movement rate is about 13 mm/a. If the geometric center of Fujian coast is used as the reference datum, Taiwan Island has a consistent (except its north end) NW-trending movement with the direction of around 50.0N by W. The maximum rate of 61 mm/a occurs along the eastern coast and decreases gradually towards west. The analysis of strain field indicates that Taiwan and its coastal area have a uniform strain field with the principal compressive strain direction of N48.0W and the principal tensile strain direction of N42.0E. The principal compressive strain rate along the eastern coast of Taiwan Island is 3.43610-7/a, which decreases gradually towards west and reaches 1.86110-8/a to Fujian coast. The collision and underthrust of Philippine Sea plate with Eurasian plate in the eastern part of Taiwan Island can be considered as the principal force for the crustal movement, deformation and great earthquake occurred in Taiwan and its coastal area. The direction of principal compressive stress in the area is about N55.0W.展开更多
Estimation of bounded populations and carrying capacity in the presence of a sample frame is considered. Models based on Logistic model are proposed. Like the existing estimators, this estimation technique deals with ...Estimation of bounded populations and carrying capacity in the presence of a sample frame is considered. Models based on Logistic model are proposed. Like the existing estimators, this estimation technique deals with initial condition and is based on yearly population totals in order to fit in a model within a given period of time in this study. The proposed Logistic model technique has shown to be efficient especially with large data. The empirical study indicated that the Logistic model is efficient and can estimate properly even in the presence of outliers.展开更多
The effects o f important parameters (beam reinforcing plates, initial post-tensioning, and material properties o f steel angles) on the behavior o f hexagonal castellated beams in post-tensioned self-centering (PTSC)...The effects o f important parameters (beam reinforcing plates, initial post-tensioning, and material properties o f steel angles) on the behavior o f hexagonal castellated beams in post-tensioned self-centering (PTSC) connections undergone cyclic loading up to 4% lateral drift have been investigated by finite element (FE) analysis using ABAQUS. The PTSC connection is comprised o f bolted top and bottom angles as energy dissipaters and steel strands to provide self-centering capacity. The FE analysis has also been validated against the experimental test. The new formulations derived from analytical method has been proposed to predict bending moment o f PTSC connections. The web-post buckling in hexagonal castellated beams has been identified as the dominant failure mode when excessive initial post-tensioning force is applied to reach greater bending moment resistance, so it is required to limit the highest initial post-tensioning force to prevent this failure. Furthermore, properties o f steel material has been simulated using bilinear elastoplastic modeling with 1.5% strain-hardening which has perfectly matched with the real material of steel angles. It is recommended to avoid using steel angles with high yielding strength since they lead to the yielding o f bolt shank. The necessity o f reinforcing plates to prevent beam flange from local buckling has been reaffirmed.展开更多
基金State Key Basic Research Development and Programming Project (G19980407) and (94) D1.
文摘Based on the station velocity data obtained from Fujian coastal GPS network and Taiwan-Luzon GPS network and the data obtained from IGS permanent stations commonly used in the data processing of both networks, the uniformity of reference frames and velocity fields of both GPS networks is realized. It has been discovered from the analysis on the velocity field in Taiwan and its coastal areas that the horizontal crustal movements in the coastal area of Fujian, Taiwan Strait and the northern part of Taiwan Island are fully consistent. The movement direction is around 26.0E by S and the rate is about 39 mm/a. The opposite variation occurs in the coastal mountain area in the eastern part of Taiwan Island with the movement direction of 30.0N by W and the movement rate of about 33.3 mm/a. In the southern end of Taiwan Island, the movement direction is 50.0S by W and the movement rate is about 13 mm/a. If the geometric center of Fujian coast is used as the reference datum, Taiwan Island has a consistent (except its north end) NW-trending movement with the direction of around 50.0N by W. The maximum rate of 61 mm/a occurs along the eastern coast and decreases gradually towards west. The analysis of strain field indicates that Taiwan and its coastal area have a uniform strain field with the principal compressive strain direction of N48.0W and the principal tensile strain direction of N42.0E. The principal compressive strain rate along the eastern coast of Taiwan Island is 3.43610-7/a, which decreases gradually towards west and reaches 1.86110-8/a to Fujian coast. The collision and underthrust of Philippine Sea plate with Eurasian plate in the eastern part of Taiwan Island can be considered as the principal force for the crustal movement, deformation and great earthquake occurred in Taiwan and its coastal area. The direction of principal compressive stress in the area is about N55.0W.
文摘Estimation of bounded populations and carrying capacity in the presence of a sample frame is considered. Models based on Logistic model are proposed. Like the existing estimators, this estimation technique deals with initial condition and is based on yearly population totals in order to fit in a model within a given period of time in this study. The proposed Logistic model technique has shown to be efficient especially with large data. The empirical study indicated that the Logistic model is efficient and can estimate properly even in the presence of outliers.
文摘The effects o f important parameters (beam reinforcing plates, initial post-tensioning, and material properties o f steel angles) on the behavior o f hexagonal castellated beams in post-tensioned self-centering (PTSC) connections undergone cyclic loading up to 4% lateral drift have been investigated by finite element (FE) analysis using ABAQUS. The PTSC connection is comprised o f bolted top and bottom angles as energy dissipaters and steel strands to provide self-centering capacity. The FE analysis has also been validated against the experimental test. The new formulations derived from analytical method has been proposed to predict bending moment o f PTSC connections. The web-post buckling in hexagonal castellated beams has been identified as the dominant failure mode when excessive initial post-tensioning force is applied to reach greater bending moment resistance, so it is required to limit the highest initial post-tensioning force to prevent this failure. Furthermore, properties o f steel material has been simulated using bilinear elastoplastic modeling with 1.5% strain-hardening which has perfectly matched with the real material of steel angles. It is recommended to avoid using steel angles with high yielding strength since they lead to the yielding o f bolt shank. The necessity o f reinforcing plates to prevent beam flange from local buckling has been reaffirmed.
