A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Towards a seismic capacity design of caisson foundations supporting bridge piers
https://orcid.org/0000-0002-3399-561X
Abstract The present work investigates, by means of finite element analysis in 3D, the nonlinear response under lateral monotonic and slow-cyclic loading of caisson foundations supporting bridge piers in cohesive soils. The study is performed with respect to the combined moment (M)–horizontal load (Q) on the foundation, and involves similar rigid cubic caissons carrying a column-mass superstructure of varying height (H) and pier-to-deck joint rigidity. The latter is simulated by a rotational spring at the deck level with parametrically varying stiffness, relating to the rigidity of the connection. The lateral load is imposed at the deck level, and the resulting M–Q load path on the caisson is mapped within the bounds of the respective failure envelope. The analysis revealed that due to pier-to-deck joint stiffness and the nonlinear coupling between the rotational and translational degrees of freedom at the foundation, the loading at the caisson head follows a nonlinear path characterized by the mobilization of a specific failure mechanism (identified as the “inverted” pendulum failure mode), triggered by the “negative effective height” effect. Interestingly, all load-paths display certain characteristics, such as a particular “overstrength” in bearing capacity that is mobilized by the foundation, irrespective of the stiffness properties and constraints at the superstructure system. Regarding the response under cyclic loading, the M–Q loops are shown to be well enveloped by the monotonic “backbone” curve for all examined cases. Finally, from the numerical results, a closed-form expression for the load-path is formulated, and a methodology to be used towards the seismic design of caisson foundations is proposed.
Highlights Seismic capacity design of caisson foundations supporting bridge piers. Simplified seismic SSI with full coupling in foundation compliance, influence of the pier-to-deck joint rigidity on the caisson response up to failure. The meaning of “negative” effective height in SFSI. Bearing capacity and uplifting at the foundation, structural yielding at the pier.
Towards a seismic capacity design of caisson foundations supporting bridge piers
https://orcid.org/0000-0002-3399-561X
Abstract The present work investigates, by means of finite element analysis in 3D, the nonlinear response under lateral monotonic and slow-cyclic loading of caisson foundations supporting bridge piers in cohesive soils. The study is performed with respect to the combined moment (M)–horizontal load (Q) on the foundation, and involves similar rigid cubic caissons carrying a column-mass superstructure of varying height (H) and pier-to-deck joint rigidity. The latter is simulated by a rotational spring at the deck level with parametrically varying stiffness, relating to the rigidity of the connection. The lateral load is imposed at the deck level, and the resulting M–Q load path on the caisson is mapped within the bounds of the respective failure envelope. The analysis revealed that due to pier-to-deck joint stiffness and the nonlinear coupling between the rotational and translational degrees of freedom at the foundation, the loading at the caisson head follows a nonlinear path characterized by the mobilization of a specific failure mechanism (identified as the “inverted” pendulum failure mode), triggered by the “negative effective height” effect. Interestingly, all load-paths display certain characteristics, such as a particular “overstrength” in bearing capacity that is mobilized by the foundation, irrespective of the stiffness properties and constraints at the superstructure system. Regarding the response under cyclic loading, the M–Q loops are shown to be well enveloped by the monotonic “backbone” curve for all examined cases. Finally, from the numerical results, a closed-form expression for the load-path is formulated, and a methodology to be used towards the seismic design of caisson foundations is proposed.
Highlights Seismic capacity design of caisson foundations supporting bridge piers. Simplified seismic SSI with full coupling in foundation compliance, influence of the pier-to-deck joint rigidity on the caisson response up to failure. The meaning of “negative” effective height in SFSI. Bearing capacity and uplifting at the foundation, structural yielding at the pier.
Towards a seismic capacity design of caisson foundations supporting bridge piers
https://orcid.org/0000-0002-3399-561X
Abstract The present work investigates, by means of finite element analysis in 3D, the nonlinear response under lateral monotonic and slow-cyclic loading of caisson foundations supporting bridge piers in cohesive soils. The study is performed with respect to the combined moment (M)–horizontal load (Q) on the foundation, and involves similar rigid cubic caissons carrying a column-mass superstructure of varying height (H) and pier-to-deck joint rigidity. The latter is simulated by a rotational spring at the deck level with parametrically varying stiffness, relating to the rigidity of the connection. The lateral load is imposed at the deck level, and the resulting M–Q load path on the caisson is mapped within the bounds of the respective failure envelope. The analysis revealed that due to pier-to-deck joint stiffness and the nonlinear coupling between the rotational and translational degrees of freedom at the foundation, the loading at the caisson head follows a nonlinear path characterized by the mobilization of a specific failure mechanism (identified as the “inverted” pendulum failure mode), triggered by the “negative effective height” effect. Interestingly, all load-paths display certain characteristics, such as a particular “overstrength” in bearing capacity that is mobilized by the foundation, irrespective of the stiffness properties and constraints at the superstructure system. Regarding the response under cyclic loading, the M–Q loops are shown to be well enveloped by the monotonic “backbone” curve for all examined cases. Finally, from the numerical results, a closed-form expression for the load-path is formulated, and a methodology to be used towards the seismic design of caisson foundations is proposed.
Highlights Seismic capacity design of caisson foundations supporting bridge piers. Simplified seismic SSI with full coupling in foundation compliance, influence of the pier-to-deck joint rigidity on the caisson response up to failure. The meaning of “negative” effective height in SFSI. Bearing capacity and uplifting at the foundation, structural yielding at the pier.
Towards a seismic capacity design of caisson foundations supporting bridge piers
Zafeirakos, Athanasios (author) / Gerolymos, Nikos (author)
Soil Dynamics and Earthquake Engineering ; 67 ; 179-197
2014-09-04
19 pages
Article (Journal)
Electronic Resource
English
Towards a seismic capacity design of caisson foundations supporting bridge piers
| Online Contents | 2014
Seismic performance of bridge piers: caisson vs pile foundations
| Elsevier | 2019
CAISSON FOUNDATIONS FOR BRIDGE PIERS IN LOUISIANA WATERWAYS
| British Library Conference Proceedings | 1999
Engineering Index Backfile | 1945