HOV-Velsen is an important public transportation link recently brought into operation between Haarlem railway station and IJmuiden. The HOV bus service runs on existing roads. To ensure the service is given priority over other traffic and keeps to the timetable, traffic control systems were installed and the roads redesigned to suit. One of the results is a remarkable concrete retaining wall in Santpoort-Noord that has the appearance of a dried-out clay soil face.
Reinforced concrete retaining wall in fine form
Retaining walls have an important role to play but are usually quite boring to look at. However, they can – as can be seen from this example in Santpoort-Noord – be more than just grey, monotonous panels. Because how a retaining wall looks can considerably effect the visual quality of its environment, it was important for the architect to create an attractive design for this project. The architect placed great emphasis on integrating the wall visually into the landscape. The inspiration for his design was provided by an image that looked like dried-out clay. He wanted the consistent pattern and rough texture produced in this material by cracks of various widths and lengths to be reproduced in the surface of the retaining wall. But he had to find a way of realising his ideas. Faced with this task, he turned to NOE Bekistingtechniek, Arkel, the Dutch subsidiary of NOE-Schaltechnik, Süssen, Germany. The company has been involved with concrete formwork and formwork technology for over 60 years and with concrete surfaces produced using textured formliners for over 40 years. NOEplast offers textured formliners under the brand name NOEplast for customers who wish their concrete surfaces to be appropriately aesthetic in appearance.
From clay soil to textured formliner
In order to realise the clay relief envisaged by the architect, the image was digitised, rastered and scaled to a size suitable for the retaining wall. All the project stakeholders were resolved that the textured surface should look as natural as possible. Furthermore, the pattern of the texture had to be capable of being extended to any height and width. This latter requirement presented a big challenge but was mastered in the end. The NOE team created a model using CNC technology. The model was used to produce a mould and intermediate negatives, which were in turn used to manufacture the textured formliners.
Multiple reuses
The textured formliner merely has to be fixed in position in the form to give the concrete the desired textured finish. In practice, however, for in-situ site structures, the formliner must be glued onto the formwork, or onto a supporting board, which is then screwed onto the formwork. In the precasting factory, it is enough for the textured formliner simply to be placed into the formwork. Depending on the actual textured formliner, it is then given a very thin layer of release agent. NOE-Schaltechnik offers a compatible release agent that has been specially designed to perform excellently with textured formliners. The pour can take place as soon as the textured formliner has been prepared. After the concrete has hardened and the formliner has been stripped, the chosen pattern is revealed as an imprint in the concrete surface. NOEplast textured formliners can be reused up to 100 times.
Special service
NOE-Schaltechnik continually strives to make its customers' work easier. Alone in being a supplier of both formwork and textured formliners, the company is able to offer a special service: on request, NOE operatives can attach the formliners to the formwork or onto a supporting panel. This is mainly of interest on sites where uneven ground, lack of space or bad weather make the installation of the formliners more difficult. Textured formliners installed in this way by NOE are delivered ready for immediate use to site or the precast concrete works.
Individualised customer designs and combinations of standard form liners
NOE-Schaltechnik welcomes requests for individualised designs from its customers. Customers' design ideas can be realised in a number of ways:
- The traditional approach is to make a model and subsequently a mould from an existing surface texture.
- Alternatively, NOE can capture surface features and characteristics digitally with a 3D scanner and create a mould using CNC technology.
- The manufacturer has been working with CNC technology for several years to create surface textures and patterns based on vector data.
NOE-Schaltechnik is therefore always in a position to offer the right solution for its customers whatever the required concrete surface design.