The Practice of Tensile Tests: Case Study Rotterdam Quay Wall

A detailed analysis of a recently performed series of tensile tests on steel anchor rods in a critical quay wall in the Port of Rotterdam, including the implications for the maintenance plan.

Project Context and Challenge

The investigated quay wall, dating from the 1970s, showed limited visual signs of deterioration. However, the owner wanted to establish a risk-based replacement plan based on data, not on visual inspection alone. The primary question was: what is the current load-bearing capacity of the existing anchorage and how does this relate to the design load?

For this project, we selected representative anchor locations based on a prior ultrasonic screening. This non-destructive method gave a first indication of possible corrosion thickness loss. Subsequently, destructive tensile tests were performed at three critical points in accordance with CUR recommendation 166.

Execution and Measurement Results

The tensile tests were performed with a calibrated hydraulic cylinder. The load was increased stepwise while the elongation of the rod and the force were continuously measured. The results showed a striking pattern:

• Anchor 1 reached the yield point at 87% of the theoretical design load.
• Anchor 2 showed linear elastic behavior up to 95%, followed by a sudden fracture.
• Anchor 3 performed above expectation, with a fracture load at 102% of the design value.

The combination with the ultrasonic data made it clear that the variation strongly correlated with local differences in the groundwater level and oxygen availability, factors that influence the corrosion rate.

Conclusion and Recommendations

The study confirmed that the average residual strength of the anchor system was sufficient for the current loads. However, the spread in the results – particularly the weak performance of Anchor 1 – underscored the importance of a statistical approach and not relying on averages alone.

Our advice to the client was twofold: a phased replacement of the 20% worst-performing anchors within 5 years, coupled with annual monitoring of the corrosion rate via ultrasonic investigation at fixed measurement points. This approach optimizes the structure's service life against minimal lifecycle costs.