Preload measurements of bolted connections in Ramspol storm surge barrier
conference paper
Measurements were performed to determine the preload of the bolted connections of the storm surge barrier in Ramspol, The Netherlands, roughly 25 years after installation. The barrier is a set of three inflatable dams, which are inflated when the hinterland requires protection from flooding but allows (commercial) vessels to pass when deflated. At the base of the barriers, the reinforced rubber membrane lies between two steel plates which are clamped together using a total of approximately 1200 M39 threaded rods per barrier.
Through friction, the forces on the inflatable barrier are transferred to the foundation.
The measurements were performed to verify the remaining preload in these critical connections, because preload loss due to relaxation of the membrane is expected over time. The results form the basis for further decision making regarding the structural safety of the bolted connection and remaining lifetime of the structure.
The preload was measured in a sample of approximately 10% of the total 3600 anchors, where for all measured locations, the preload was released from the anchor. This paper describes the measurement setup and the measurement procedure, the results and statistical analyses and provides an expectation for the preload of all anchors, based on the sample test.
Through friction, the forces on the inflatable barrier are transferred to the foundation.
The measurements were performed to verify the remaining preload in these critical connections, because preload loss due to relaxation of the membrane is expected over time. The results form the basis for further decision making regarding the structural safety of the bolted connection and remaining lifetime of the structure.
The preload was measured in a sample of approximately 10% of the total 3600 anchors, where for all measured locations, the preload was released from the anchor. This paper describes the measurement setup and the measurement procedure, the results and statistical analyses and provides an expectation for the preload of all anchors, based on the sample test.
TNO Identifier
1017871
Publisher
TNO
Source title
IABSE Congress Ghent 2025 – The Essence of Structural Engineering for Society, Ghent, Belgium, 27-29 August 2025
Pages
2046-2053
Files
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