Patrick LABUSSIERE, Spie batignolles "3DR filter formwork removes two phases on the construction site, reinforcement and form removal, which corresponds to a significant time saving."
Eric TRICHET, MERCEDES construction site "Traditional formwork requested high cost tools and important adjustments."
Armand CORVIOLE, Ital Cementi Group "We consider that this process is viable with traditional cement concrete filling."
> Patrick LABUSSIERE, SCGPM, Spie Batignolles, TDF construction site carried out in Dipy, answers our questions.
The inventors of DIPY formwork also developed the current 3DR. As a user of both versions, we would like to collect your opinion on these technologies.
1. You used DIPY formwork on TDF construction site, can you give us the reasons of your choice?
Firstly, the particular form of the structure. The DIPY formwork which adapts to the specific forms answered the specific problems.
Secondly, as the technical proverb known as “the prime contractor relies on 3 criteria: the first is ‘how much does it cost ?', the second is ‘how much does it cost ?' and the third is ‘how much does it cost ?'”. On the basis of this principle, and by comparing the various alternatives which were offered to us, it was decided that the DIPY was the most economic system.
Moreover, DIPY system makes it possible to save a step (form removal) on the logistic chain and thus in time, which is an obvious advantage on a construction site.
2. Which were the other alternatives for this construction site?
The form of cone of the structure left us the choice between various techniques:
- The climbing formwork
- The DIPY filter formwork system
Each one of these processes was considered for this construction site and the Dipy formwork, even if the technique were recent, featured major assets in terms of time and cost.
3. Since you carried out tests with 3DR version. Do you think that this new generation meets the needs for the construction site better…
…in term of time? 3DR filter formwork removes two phases on the construction site, reinforcement and form removal, which corresponds to a significant time saving.
…in term of durability? Already thanks to the Dipy filter system, the concrete eliminated a part of surplus water and led to a less porous concrete. The 3DR takes again this principle and associates a woven and three-dimensional cage reinforcing. Durability appears to me still reinforced with the new 3DR technology.
…for other reasons? With 3DR technology, the reinforcements are installed in factory. The construction site gains thus in safety, time and simplification of the organization.
4. Which are the improvements you expect on this technology…
…in term of construction site? If there were improvements to bring to the system, I think that it would be on the level of safety equipment and accessories on the vertical veils.
Moreover, a new method induces a phase of training. But in spite of this apprehension, the time and the difficulty of formation are singularly short.
…for the building owner? You know, the building owners react more like financials than like technicians. Thus it is necessary well to insist on the durability induced by the system.
…for the prime contractor? It is the same thing, it is necessary to take care to reassure the customer and to guarantee to him that, with the support of testings and trials, veils in 3DR, even with great height, can hold with casting.
5. Which are, according to your company, the relevant applications of this process?
Obviously, 3DR process is largely better than the other systems with regard to specific forms, rehabilitations and veils run against ground or existing structures.
Moreover, because of the lightness of the veils, it appears ideal where crane cannot be used (near schools or under ground construction sites).
I think that in the long term, it will become a serious competitor of the traditional formwork for all that relates to the "traditional" construction sites.
6. Are you ready to use 3DR on forthcoming construction sites?
Yes, after technico-economic assessment. It is certain that 3DR system is ideal for the works mentioned before and that it has an assured future in the construction sites.
1. Which were the competitor systems for the construction of the cone?
We had several alternatives for the construction of this rather complex structure:
- Traditional formwork,
- 3DR Structural Formwork.
2. Why did you choose 3DR formwork?
Two points were essential:
- Cost: according to several studies on the various systems, it proved that shotcrete caused problems in the installation of metal reinforcement, moreover, for a required thickness of shotcrete of more than 15 cm, the loss of product involves an important overcost. Traditional formwork required high cost tools and important adjustments. The pre walls bring a filler concrete saving because of the thickness of their pre-slabs, but the filling can be done only by height of maximum 1m00. In a global approach, the most realistic solution was the 3DR formwork which presented in addition the interest of flexibility.
- Time: We were limited in time for this construction site, the high slab having to be delivered as soon as possible. 3DR formwork enabled us to regard the walls only as preparings. Moreover, from the conical and eccentric architecture of the work, installation of the form panels required quick panels readjustments the ones with respect to the others and connection to the intermediate slabs.
3DR formwork brought in addition a facility of organization of the construction site, because it is a portable product and which is not removed. It is managed like a pre made veil, like a preparing, which fulfilled the requirements of the construction site.
Moreover, as regards delivery, conversely to pre walls which require a delicate coin by coin unloading with the crane, because they are heavy veils, and storage on specific racks, 3DR formwork, easier and lighter structure, does not present the problems of unloading and storage, particularly sensitive on a construction site with tight schedules.
3. Did 3DR answer your expectations?
I am satisfied with the product because it well adapted to the complexity of the structure, and that until the last moment (it was necessary to change from ST20 to ST40 very quickly!).
At the end of the day, 3DR formwork respected the shape of the eccentric cone and the requirements of pouring.
To summarize, one would not have done better with other systems.
4. Which are the points to be improved?
There are some small refinements to bring to the product, in particular on the level of coverings. But considering the form of the structure, complications at the junction of the panels had to be expected. It would also be necessary to facilitate maintenance of the panels in provisional phase by incorporating in the cages the push-pull fastening devices.
In a general way, the 3DR is a new product, which requires a phase of training for the installation of the panels, but the formation proved to be simple and fast for the workmen.
5. Is this a system which you would use again?
I think that 3DR formwork is very suitable for the complex structures and that this system has an unquestionable future for rehabilitation works. Moreover, on this construction site, today the architect is satisfied, whereas it was reticent to call upon a new product.
To the request of Philippe DURAND, Unibéton contributed his share to the candidature led by Coffratherm for the European project for 3DR process since 2000. Unibéton is the Company of the Italcementi Group in charge of production and marketing of the ready-to-use concrete for France.
[...] We consider that this process is viable with traditional cement concrete filling. That was confirmed by the references of construction sites which were carried out with former process DIPY existing before 3DR.
In addition, after a marketing analysis and technico-economic advice of a house manufacturer, we carried out a study on the application of this process in house construction.
We more specifically undertook this study with Phillipe DURAND on alternative light concrete fillings.
These studies showed that the implementation was viable for a standard formwork, which we carried out in our technical center of Guerville.
[...] We are always willing to continue with the holders of the process a co-operation to realize this concept.