Webinar: Post-failure Investigation of the Collapse of Caisson CI14 and Implications to Design

This is the recorded session of the technical webinar from June 28, 2023 on post failure investigation using DIANA of the collapse of caisson CI14 and implications to design.

Presenters: Chris Zeris - Professor and Director, Laboratory of Reinforced Concrete, Head of Division of Structural Engineering, National Technical University of Athens

On the night of November 27, 2020, Caisson CI 14 collapsed catastrophically while being in the final stage of ponding operations, off the coast of Piraeus; at that time, one bulkhead gave away and water filled one of the compartments, while the caisson was just 30cm above the final position. The reinforced concrete caisson was  20x30 squ.m. in plan and 30m tall, as part of the Southwards expansion of the Port pf Piraeus works (Phase A), comprising 62 caissons. Given the fact that one caisson had already been positioned in place in September and four were constructed and floating, pending to be installed, a comprehensive study was undertaken, following a request by the Contractors and the Designers, in order to: i) evaluate the influence of the bulkhead failure and establish the cause of the collapse, ii) investigate possible design issues, iii) establish the suitability or not of the remaining caissons to be positioned in place and iv) propose possible additional construction and design changes for the remaining caissons to be constructed, to avoid problems for the remaining part of the project.

In this webinar, we present the information on the problem, the site investigations and the structural and thermal/maturity analyses performed using DIANA, in order to establish the failure sequence and the implications of this failure to the design and construction of this type of structures.