Lock renovation: why do you need a test campaign?
The decision of renovating a lock instead of building a new one depends on numerous factors. This blog explains why a test campaign needs to be carried out on the concrete components of a lock before a decision on the lock renovation can be made.
The renovation of the concrete components of a lock commences with a visual check of the lock. If the as-built reinforcement plans are available, certain decisive sections of the lock will be recalculated. From these calculations it might be evident that some sections will need to be replaced anyway and hence these sections need no further investigation, avoiding unnecessary time and costs.
Based on the insights obtained, a test schedule can be drawn up. Cores are drilled to determine the depth of the carbonation and to determine the chloride content at different depths. The concrete cover is mapped, and the reinforcement diameters and reinforcement arrangement is investigated in order to check the reinforcement plans. Cores are drilled to determine the compressive strength of the concrete. If there is insufficient data on the concrete composition, petrographic studies can be considered as well.
It is possible that the test campaign is carried out in several phases. In a first phase, the focus is the general picture of the condition of the lock: what is the cause and the severity of the damage? Is it a general or local problem? In the next phase, more attention can be paid to specific sections to start zoning areas for possible solutions. Additional investigations can also be carried out to investigate the suitability of a certain solution (e.g. investigation into the conductivity of the concrete and the connection of the reinforcement, if cathodic protection is considered).
By carrying out a thorough testing campaign, insight is gained into the nature, extent and cause of the damage. This allows different renovation concepts to be conceived with their associated residual life, expected costs, time impact, maintenance scenarios and maintenance costs. On this basis, the lock operator can make an informed decision and minimises his risks.
A few years ago SBE was involved in the renovation of the Van Cauwelaert lock. Photos of the renovation are shown below. It was decided to completely remove the outer shell (0.50m) of the concrete walls and replace it in its entirety, given the advanced state of degradation.
For more information about the project, click here.