Basically, the use of cold-formed steel bearers in structures requires not only the consideration of dimensioning principles of conventional steel structures but also other principles, as cold formed steel bearers react differently than hot-rolled heavy steel components under load and they have a different collapse mechanism. Similarly, the profile shapes of [cold formed steel] components, their manufacturing methods, their fasteners and use in the structure differ from conventional steel structures in many respects. Therefore, the existing standards for steel structures do not include this type of structures. Accordingly, in the context of its R&D activities, APEC Design Team has determined the design principles in the standards defined in the European Union, United States, Canada and other countries and has developed its own design methods incompatible with applicable bearing tolerance standards. APEC continues to develop its own design methods. APEC compares the results of its R&D work to the references in the international literature and develops finite element and experimental models. APEC’s R&D work relies upon the compatibility of the design of structural building components and their incorporation to the building structural system with the basic premises of structural analysis, the designated functional utility and the overall capability of the building. It follows that APEC’s design principles consider the design methods in the conventional buildings as well as the innovations which are the results of its R&D process. In this regard, the APEC Design Team carefully reviews the latest scientific literature and updates its design methods.
Another design principle of APEC is to consider the limits of resistance and utility to ensure the necessary level of structural resistance, stability and rigidity for the safe performance of all utility functions of the building during its service life.
Except for snow load, wind pressure and seismic load, structural design load values which are relied upon in APEC’s design phases are determined in accordance with TS 498 and international standards. TS EN 1991-1-3 is taken into consideration in determining the snow load. TS EN 1991-1-4 is taken into consideration in determining the wind pressure. The conditions in the Regulations Concerning the Design of Buildings under Earthquake Effect dated March 18, 2018 (“Turkish Earthquake Regulations”) are taken into consideration in defining earthquake effects and risks. In order to determine the necessary resistance, load combinations, which are generated by the calculations of typical loads and in accordance with the selected design method, are presented separately. Utility has been defined as “the conditions which provide for the following for the building under its anticipated usage conditions and load: The fulfillment of its expected functions; the protection of its appearance and its resistance to external (environmental) factors, the prevention of negative effects upon non-structural elements; the comfort of the users”. Utility limits have been defined as the limits of conduct quantity under certain load combinations such as displacement and acceleration. The conditions for structural integrity are evaluated independently of other resistance conditions.