Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Effect of Vertical Ground Motions on Shear Demand and Capacity in Bridge Columns
The objective of this project was to examine the effects of axial force variation in bridge columns due to strong vertical ground motions and the influence of these axial force fluctuations on shear strength degradation. Two quarter scale specimens (SP1 and SP2) with different transverse reinforcement ratios were constructed and tested on the UC-Berkeley shaking table at the Richmond Field Station. As a result of an extensive numerical investigation and preliminary fidelity tests, the 1994 Northridge earthquake acceleration recorded at the Pacoima Dam was selected as an input motion for the shaking table study. The chosen ground motion was applied to the test specimens at various intensity levels ranging from 5% to 125% of the actual recorded motion. As part of the computational modeling, a new shear spring model which incorporates shear strength estimations based on ACI and Caltrans SDC equations is developed and implemented in the computational platform, OpenSees. The models are reasonably successful in capturing the shear-force and displacement histories measured during the tests. The study indicates that strong vertical excitations can induce axial tension in the column which causes marginal degradation of the shear strength (mainly due to the degradation of the concrete contribution to shear strength). The degradation did not adversely affect the performance of the column. Since the vertical frequency of bridge columns is much higher than the transverse or longitudinal frequency, the imposed axial tension is sustained for very short durations. The present study of a single column bent suggests that ignoring the concrete contribution to shear capacity when the column is in tension is conservative.
Effect of Vertical Ground Motions on Shear Demand and Capacity in Bridge Columns
The objective of this project was to examine the effects of axial force variation in bridge columns due to strong vertical ground motions and the influence of these axial force fluctuations on shear strength degradation. Two quarter scale specimens (SP1 and SP2) with different transverse reinforcement ratios were constructed and tested on the UC-Berkeley shaking table at the Richmond Field Station. As a result of an extensive numerical investigation and preliminary fidelity tests, the 1994 Northridge earthquake acceleration recorded at the Pacoima Dam was selected as an input motion for the shaking table study. The chosen ground motion was applied to the test specimens at various intensity levels ranging from 5% to 125% of the actual recorded motion. As part of the computational modeling, a new shear spring model which incorporates shear strength estimations based on ACI and Caltrans SDC equations is developed and implemented in the computational platform, OpenSees. The models are reasonably successful in capturing the shear-force and displacement histories measured during the tests. The study indicates that strong vertical excitations can induce axial tension in the column which causes marginal degradation of the shear strength (mainly due to the degradation of the concrete contribution to shear strength). The degradation did not adversely affect the performance of the column. Since the vertical frequency of bridge columns is much higher than the transverse or longitudinal frequency, the imposed axial tension is sustained for very short durations. The present study of a single column bent suggests that ignoring the concrete contribution to shear capacity when the column is in tension is conservative.
Effect of Vertical Ground Motions on Shear Demand and Capacity in Bridge Columns
H Lee (Autor:in) / P Kumar (Autor:in) / S Gunay (Autor:in) / K Mosalam (Autor:in) / K.S Kunnath (Autor:in)
2012
180 pages
Report
Keine Angabe
Englisch
Shear Capacity of Bridge Pinned Columns
| NTIS | 1994
Pseudodynamic responses of bridge columns subjected to earthquake ground motions
| British Library Conference Proceedings | 2002
The Effects of Near Fault Ground Motions on Bridge Columns
| British Library Conference Proceedings | 1997
Vibration control of suspension bridge due to vertical ground motions
| SAGE Publications | 2020