CURTAIN WALL APPLICATIONS IN OUR COUNTRY, PROBLEMS AND AN APPLICATION

Especially in multi-storey buildings, the system, which emerged when the reinforced concrete or steel skeleton made the load-bearing walls unnecessary and which is referred to as "curtain wall" from the terms "cladding wall" and "curtaln wall", continues by hanging on the slabs or columns and passing in front of it. The curtain wall, which we divide into vision area and parapet area, which transmits its own weight and wind directions to the structure with aluminium or, if necessary, steel construction reinforcement, is covered with glass in the vision area and with glass or another deaf material in the parapet area; aluminium composite panel, natural artificial stones, etc.

One of the first examples of the curtain wall, which was first used in the world in 1820 in a two-storey bank building in America, is the Kızılay business inn built in Ankara in 1959. Then, the Highways Building in Zincirlikuyu, which was built with the project of architect Mehmet Konuralp between 1973-1979, is one of the successful applications. In the following years, curtain wall systems started to be produced in our country and with the increasing demand, they started to be widely used especially in the architecture of business centres. When we compare the years 1820 and 1959, the difference of about 140 years is almost closed with the ease of information flow and sharing today, and the building materials and technology used anywhere in the world, curtain wall system; If it is accepted, it has started to be produced or imported in a few years later.

The reality of our country

The fact that curtain walls have a modern and prestigious effect, increase the value of the building, provide heat and sound insulation, eliminate the need for exterior paint, are easy to clean, can be applied quickly, reduce the weight of the outer building shell by approximately 25%; has increased the demand in the field of curtain walls in our country as in the whole world, extending to the side streets. Thus, especially in our big cities, many companies that want to meet this demand, who do not have infrastructure and technical personnel or insufficient, have been formed; unconscious, incomplete applications that do not comply with the technical specifications to be followed have become a threat to human safety.

As in many issues from the building production process to traffic rules, the fact that both practitioners and investors look at this issue with "an understanding that applies the rules to be followed only when there is a heavy sanction and sees it as an unnecessary bureaucratic procedure" causes this result. However, in addition to the requirements of economic, aesthetic integrity, prestigious result in curtain wall project design and application; Measures should be taken against earthquake, wind loads, fire, heat, sound and water insulation, corrosion, necessary calculations should be made and details should be solved according to these criteria. Many companies in our country ignore all these criteria and finalise the most economical solution for themselves without producing details, in the construction site environment, with assembly teams without technical competence.

A large-scale company that consumes 600 tons of aluminium curtain wall material per year does not make wind load calculations in accordance with the specifications, chooses the most economical horizontal and vertical load-bearing elements and moments of inertia for itself without questioning, does not go to the selectivity of the expert company in the project and application in employers and users, generally accepts the most economical or the solution that looks the best at first glance, does not seek any technical specifications or cannot control it during the application. This situation reduces the chances of medium-sized companies that want to make the application according to the necessary criteria, feel responsible for the application, think about the future, and employ personnel with technical infrastructure to compete with other under the stairs companies.The 17 August earthquake caused the deaths of thousands of people, the destruction of approximately twenty buildings and billions of liras of material loss, and the building inspection mechanism that emerged afterwards could not go beyond inspecting only the rough structure. The success achieved in the inspection of the rough structure is a matter of discussion. However, building supervision should ensure that all components of the building, including the curtain wall, from the foundation to the fine structure, have the necessary technical specifications at the application stage. The weight of a pair of 6+12+6 mm. thick, 120 x160 cm. double glazing used in the façade is approximately 60 kg, and the breakage of even one module from the façade of a high-rise building would pose a serious danger. Or if the fire breakers are not made in accordance with the specifications, it will cause a fire to spread rapidly to other floors. However, unfortunately, many implementing companies, employer companies and building inspection companies do not care about the seriousness of this.

An App

The building, which was built on a corner parcel on Avcılar E5 Highway, was completed with structural Silicone and Aluminium composite Panel Curtain Wall. While the architectural project was being prepared, the curtain wall project was also reduced together. Thus, there was no harmonisation problem after the rough construction was completed. With the concerns of increasing the advantage of the corner parcel and creating a building with a unique identity by standing out from the monotonous urban texture, the main entrance of the building was given from the corner and this corner entrance was tried to be emphasised a little more with a cylindrical form on the upper floors.

In order to create this form, twisted circular, sandblasted and anti-rusted epoxy painted NPI and NPU steel beams were fixed on reinforced concrete starting from the 1st floor with the help of 15 mm. sheet plates and chemical dowels. Horizontal and vertical profiles were selected by calculating the moment of inertia of the vertical and horizontal aluminium profiles that can meet the wind load of 96 kg/m2 per square metre (141 km/h), which is required up to 20 m. building height specified in TS 498, which was created with the data of floor height, maximum deflection amount, vertical carriers axle spacing, glass thickness. Modules were formed according to the criteria of minimum waste of aluminium composite panels and ensuring aesthetic integrity in interior and exterior spaces.

Against fire; in order to provide smoke insulation between floors, 2 mm. galvanised sheets were attached to the lower and upper level of the beam with plyizobutylene tapes without connecting to the curtain wall profiles. Absolute smoke impermeability; the contact surfaces of these sheets with reinforced concrete and horizontal vertical carriers were provided with fuga type siliconisation. In order to provide sound insulation between the floors, stone walk was filled between the two fire stop galvanised sheets along the exterior beam height. On the flat surfaces; 6 mm. pyrolotic blue reflective, tempered, machine-grinded glass, 12 mm. air gap in between, 5 mm. flat glass was used on the inside.

In the parapet glazing, 6 mm. pyrolotic blue reflective, tempered, machine-grinded single glass on the outside and 5 cm. thick spandrel panel with 50 kg / m3 density stone walk detection galvanised sheet was used behind it. Reflective glass in the parapet area; black polyester foil was applied on the back of the outer glass as it may show the rockwool insulation material on the back surface from time to time depending on the light. In the circular section; since the glass bent by heat treatment cannot be tempered, 6+4 mm pyrrolotic blue reflective, machine-ground laminated glass was used on the outside.

On the deaf surfaces; Pvdf painted on iron construction, 0.5 mm aluminium on both sides, 3 mm polyethylene filled aluminium composite panel with 15 years warranty was used and all fasteners were preferred stainless steel to eliminate the problems caused by rusting over time. Heat insulation integrity was ensured by using 5 cm. thick stone walk with a density of 50 kg/m3 on the deaf surfaces under the aluminium composite panel. Vapour permeable, non-water permeable membranes were used to prevent water from entering into the system, especially under the upper harpuşta in the areas deemed necessary.

Mehmet Beşe POLATKAN / Architect - YTÜ)