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New generations of architecture are developing themselves towards dynamic and interactive designs. The graduation project is a first step in concretizing this conceptual future image by researching on possibilities of making space frames dynamic. The project has been approached from a practical point of view, striving for structural and technological feasibility.

Project Koningin Julianaplein omvat een nieuw te bouwen hoogbouwproject naast Den Haag CS. Voor zover bekend heeft het bouwwerk (nog) geen officiële naam, zodat wordt volstaan met een plaatsgebonden aanduiding: project KJ – plein. Het project vormt een onderdeel van de toekomstvisie van het stationsgebied, welke weer een onderdeel vormt van het Masterplan Den Haag Nieuw Centraal. Het gebied rondom Den Haag CS profileert zich vooralsnog tot een onaantrekkelijk overgangszone tussen het historische stadcentrum en een modern kwartaal. De gemeente Den Haag schreef voor de nieuw te bouwen hoogbouw naast Den Haag CS een prijsvraag uit. Dit gebeurde in samenwerking met NS Poort en Multi Vastgoed. Het winnende ontwerp kwam van O.M.A., het architectenbureau van Rem Koolhaas. Deze ontwierp hiertoe een spraakmakende stationsentree die perfect aansluit op de stedenbouwkundige richtlijnen voor dit gedeelte van de stad. Het ontwerp omvat ruim 100.000 m² waarvan 42.000 m² is bestemd voor kantoren, 34.000 m² voor woningen en 4.300 m² voor commercie en overige voorzieningen. Daarnaast wordt onder het koningin Julianaplein parkeergelegenheid gesitueerd (11.500 m2), tezamen met een fietsenstalling (7.300 m2). Hoewel het ontwerp één geheel vormt, bestaat er een duidelijk onderscheid tussen een woon- en kantoorgedeelte. Laatstgenoemde steunt hierbij af op de woonvleugel en geldt zodoende als afhankelijk. Voor de uitvoering betekent dit dat het woongebouw voldoende gereed dient te zijn alvorens de koppeling gemaakt kan worden. Architectonisch gezien vormen beide gebouwdelen een volledige harmonie. Constructief gezien gelden echter grote verschillen. De uitdaging bevindt zich hierbij vooral in het kantoorgedeelte. Deze wordt gekenmerkt door 22 verdiepingen met aan weerszijde twee enorme overstekken. Ter versterking van het beoogde dynamische karakter kraagt het overstek, terzijde van gebouw Stichthage, over deze heen uit.

The construction of free form building stagnated, due to the high construction cost of it. Double curved surfaces are only applied at projects with a high profile and projects above average budget during years. The problem with double curved surfaces is mainly the formwork. The present days used techniques to construct these formworks are statically. For example: wooden, steel or milled EPS formwork could only be used for one shaped elements. The lack of repetition and so the reusability of the formwork, which means that for a free form surface for every element a unique formwork is needed, makes the construction very expensive. A feasible way for mass production of unique shaped double curved elements could be achieved by a flexible formwork: a formwork that can be adjusted in every desired shape. It consists of a flexible layer that can be deformed into the desired curved surface by adjusting for example pistons, actuators or pins. Recently K. Huyghe and A. Schoofs have executed a series of experiments with a flexible formwork, build earlier by D. Rietbergen and Dr. Ir. K. Vollers. The purpose of this master thesis was to solve more aspects of the flexible formwork, and to make it a feasibly system. The main focus was the behavior of the flexible layer, at some places the flexible layer did not though the actuators. Predicting the behavior of the deformed flexible layer makes an accurate production possible. To be able to determine the behavior of the flexible layer some models are proposed. With these models the reaction forces at the supports could be determined, compression forces means that the flexible layer though the supports. The first model that is proposed, is for a single curved element. For the double curved mould surface two models are proposed, a plate model and a strip model. With tests at the Stevin Laboratory these models are verified, and some other aspects are tested, for example the flexible border of the formwork. Tests indicate that a plate is not suitable for the flexible layer, it buckles due to the plate stresses. The strip mould consists of two layers of strips, perpendicular to each other. The top layer of the strips is the mould surface. Tests showed that it is possible to produce double curved elements with the strip mould. Conclusions and recommendations. The models that are proposed in this thesis describe the behavior of the flexible layer well. A plate does not fulfil the function of a flexible layer. Tests have shown that it is possible to produce double curved elements with the strip mould as flexible layer. To cover the strips an additional layer is needed. In these tests polyether is used, as well for the borders. The protection of the polyether with sealant made the concrete element very rough. Another material has to be found as elastic layer, or to protect the polyether.

A method for forming a double-curved panel from a flat panel, which comprises processing a plastically deformable flat panel or rendering the flat panel plastically deformable to enable it to mould itself to a predetermined shape, wherein the shape is obtained by a primary supporting construction cooperating with a secondary supporting construction, wherein the primary supporting construction may or may not be adjustable to an invariant position that determines the shape, and the secondary supporting construction is adjustable between a starting position in which it supports the flat panel.

This paper discusses the effect of intentional deformation of a flexible formwork after casting of the concrete and the influence of the characteristics of concrete in the fresh state on the quality of a concrete element. This deformation is intended to bring the concrete element in its desired final shape; the deformation typically takes place in the first hour after casting. In this research thin double-curved precast shell or cladding elements are considered. The paper introduces the method used to support the flexible formwork and focuses on the concrete technology necessary to control the process of deformation after casting. Relevant parameters are discussed that influence the concrete’s behaviour shortly after casting. Rheological characteristics of the fresh concrete appear to be particularly important for the design of a suitable mixture. Since from traditional concrete research little experimental data on deformation after casting appeared to be available, experiments were carried out to test a number of prepositions. Results of these experiments are shown as well.

This paper discusses the effect of intentional deformation of a flexible formwork after casting of the concrete and the influence of the characteristics of concrete in the fresh state on the quality of a concrete element. This deformation is intended to bring the concrete element in its desired final shape; the deformation typically takes place in the first hour after casting. In this research thin double-curved precast shell or cladding elements are considered. The paper introduces the method used to support the flexible formwork and focuses on the concrete technology necessary to control the process of deformation after casting. Relevant parameters are discussed that influence the concrete’s behaviour shortly after casting. Rheological characteristics of the fresh concrete appear to be particularly important for the design of a suitable mixture. Since from traditional concrete research little experimental data on deformation after casting appeared to be available, experiments were carried out to test a number of prepositions. Results of these experiments are shown as well.