While complying with statutory and regulatory requirements, we always strive to achieve continual improvement in the performance of the Quality Management System. We enhance our excellence in projects to the client satisfaction.

Our experienced engineers, qualified supervisors, operators and foremen on site make a major contribution to facilitate the technical success of diaphragm walls. Supporting factors are the equipment used and the implemented QS/QC standards on site in combination with project schedule.

Koden is a world wide operating supplier of marine electronic products .The basic unit of these naval ultrasonic reading tools has been adopted for the application of quality control during diaphragm works. The principle is based on sending ultra-sonic waves through the bentonite slurry, after the panel was excavated. To obtain best results, the slurry should be de-sanded for the purpose of taking readings.

The ultrasonic head is lowered into the open panel and waves are sent out while lowering the Koden unit into the panel. The system is attached to a frame and moved by a precision winch that monitors the depth during the readings. The waves are sent to the front side of the excavated panel. Once the distance is set between the reading unit and the exposed joint, all readings taken should show the same distance. Those areas which show significant differences indicate the likelihood of excess concrete along the joint. In most cases, this is a clear sign that the concrete must be removed by a crane operated chisel.

These ultrasonic readings are very easy to integrate into the production process, since there is enough time to place the Koden unit and lower it into the panel during de-sanding of the slurry in the panel. Special attention has to be given to the interpretation of the readings, since the unit measured is the time for the ultrasonic wave that travels from the sender back to the sender after reflection at the exposed joint. The travel time of the ultrasonic waves through the bentonite slurry depends on the specific weight of the slurry that might differ over the depth of the panel. Therefore, adjustments have to be made to receive clear results for further decisions. The most significant advantage of the Koden readings is that the results are available before concreting the panel and therefore, correction along the joints is possible while the panel is still open and the equipment is on site.