Construction logistics, electrical installation, Velser Tunnel

After almost 60 years, it was time for major maintenance to allow the Velser Tunnel to once again meet modern requirements in the areas of safety and traffic flow. The contract for the renovation and maintenance for several years was awarded by Rijkswaterstaat (Directorate General of Public Works and Water Management) to the Hyacint construction consortium, which was made up of Dura Vermeer, Besix and SPIE. Croon was given the contract for positioning and installing the electrical installation.

Saan looked after the logistical part of the positioning of the electrical installation for Croon: receipt, storage, just-in-time delivery and positioning on the construction site. The challenge was that there was little or no space at or around the Velser Tunnel to permit storage, nor did the Hyacint consortium have any capacity to put together a logistics team. Croon chose to involve Saan for the implementation of this process because of its good experience with Saan on the Coen Tunnel. At the Velser Tunnel, the same problems were encountered: areas difficult to reach, no storage capacity and heavy equipment such as switchboxes and transformers. And the delivery times had to be more flexible than the suppliers could manage. Most of the equipment could only be stored in the correct area if other subcontractors had provided the space. Because of these very complex construction flows, the precise delivery times were difficult to determine. Thanks to its collaboration with Saan, the client was able to focus on its own work. They only needed to ring Saan to have the equipment delivered. The efficiency and ease of this collaboration led Croon to decide to rely once again on Saan’s capacity.

Logistical process 
The logistical process for the positioning of the electrical installation in the tunnel was set up by Saan from the following elements:
- Logistics hub: A hub was created at Saan’s warehouse. All the required processes could be carried out here.
- Cross-docking: In order to group several flows of goods, cross-docking was implemented in the hub. As a result, different transportation flows from various suppliers could be combined into one logistical construction flow.
- Storage: Goods that were not needed immediately were temporarily stored in Saan’s warehouse. So no storage space was required on the construction site.
- Handling on the construction site: Saan transported and positioned the equipment at the right location on the construction site. So the equipment could be delivered just in time.
Parties involved 
To coordinate the processes, Saan appointed a project leader and a coordinator. In consultation with Hyacint they coordinated the tasks including the storage for Croon’s suppliers. These suppliers included:
- Aqualectra (about 120 switchboxes)
- Siemens (7 transformers)
- Schreder (2,024 light fittings)
- Flygt (9 high-pressure submersible pumps).
Implementation, evaluation and results 
The equipment was delivered to Saan in Week 1 of 2016 and put into storage. Well before implementation, Croon’s supervisor in collaboration with Saan labelled the machines for loading in the right order. Delivery to 4 buildings commenced in Week 2. During the process there was a supervisor present on site to maintain contact with Croon and to determine the how to organise the transportation through the tunnel. The various pieces of equipment were delivered in the right order and by location with the aid of Tautliners, curtainsiders or box vans with cranes, depending on the situation. It turned out from the evaluation with Croon that all the work had been done to its satisfaction. The process was carried out without damage, the deliveries were made in a flexible manner and there was no storage on the construction site. As a result, the efficiency benefits that Croon had expected were delivered.