Projeler

Steel Execution: Algan çelik

 

Construction of a new building came up in Robert College campus in Arnavutkoy since the existing cafeteria could not meet the school’s needs but the management aimed for a transformation to respond to the requirement by changing the function of the existing indoor sports area covered with a membrane (called as Bubble) due to the fact that the land was not available for construction. It is aimed to cover the north and south façades of structure covered with a vaultlike sheet in existing contours with glass and make contact with its environment and nature from basement and gallery floor. All out-facing façades in basement level outlooking the overhang are closed with sliding façade system working with connection details adjacent to the floor and ceiling, designed without profiles by our office in order to associate interior and exterior areas of usage and bringing the nature inside the structure. It is aimed to bring the vegetation and trees on the outside to the interior by splitting the concrete terraces and to provide a strong connection between the interior vegetation pools with the green exterior to provide a positive accoustic effect in the cafeteria, enable a clearer definition of the space by dividing the volume into three and make the users feel as if they are in an exterior space. Vault cover is designed as a double-walled system in order to give the feeling of an exterior space irrespective of where they are, to maximize the use of daylight inside the structure, to make contact with the exterior atmosphere to perceive the effects of various times of the day and seasons on lighting but to control the light and temperature inside the structure simultaneously. 5-layered polycarbonate sheets mounted on steel supporting structure are used as the first layer protecting the structure from rain and cold while the second layer is composed of oriented metal sheets specially designed for controlling daylight and heat, metal cover reinforced with triangular diffractions for stability and structure supporting the cover. 50cm gap between the walls forms a climate cushion in which air can easily move up and contributes to air conditioning inside the structure. Overhangs having consoles over three meters on glass façades sitting on ground at around 2.5 meters above the soil surrounds the building, protecting glass façades and exterior terraces from the sun. Further to our structural analysis, the existing space frame system had to be dismantled and re-constructed with a new system to fulfill specifications including earthquake since the existing system was designed only to protect the indoor sports area from rain and wind, and collapsed on the middle in time with its supports spread out by two centimeters. However, since the zoning conditions did not let this and further to our search for a more rational and economical solution, a deliacate and extremely economical system where the structural members specified above having more than one function and worked together with reinforcement only at required points further to calculations has been applied.

Further to bringing the supports to correct position, vault has been strengthened on the west façade by connecting the supports with new gallery floor construction with special details designed for the space frame system nodes and further spreading out is prevented by the new forces and loads on the west façade. Supports on the east façade of the symmetrical structure are fixed with diagonal members placed in overhangs with a console length of 3.5 meters on horizontal planet o act as a horizontal beam, preventing any further spread-out.

The existing space frame construction which has no chance to stand against the new double- walled roof covering and associated loads (wind, snow, earthquake) has been supported with steel columns having diameter of 14 centimeters at definite intervals at its highest point, and at support points, existing nodes and required space frame pipe elements in accordance with the result of the analysis. In order to prepare the strengthening design accordingly, approximately 1830 structural elements were analyzed, samples have been taken from existing structural members and examined in laboratory.