Taşıyıcı sistemi çerçeve - tüp olan bir yapının yatay yükler altındaki davranışı

Abstract

Yüksek yapılar, insaa edildikleri ülkenin inşaat sektörünün yapısına, özeJ İlklerine ve yaygın kullanılan malzeme ile gerçekleştirilir. Yurdumuzda gerek çeliğin pahalı bir malzeme olması, gerekse betonarmenin çok yaygın olarak kullanılan bir inşaat malzemesi olması gibi neden ler J e yüksek yapıların tamamı betonarme kullanılarak inşaa edilmiştir. Bu çalışmada yüksek yapılar, kullanılan malzeme türüne göre sınıflandırıldıktan sonra hesaplarda gözönünde bulundurulacak yükler belirtilmiştir. Dördüncü bölümde yatay rijitlik temini için kullanı lan taşıyıcı sistemler tanıtılmış besinci bölümde çerçeve- tüp sistemlerin davranışı, hakkında detaylı bilgi verilmiş tir. Altıncı bölümde çerçeve-tüp taşıyıcı sistemli bir yapının dinamik ve eşdeğer statik yöntemle hesabı, sistem için kurulan üç ayrı modelde, oldukça etkili bir statik ve dinamik hesap programı olan SAP 90 ile yapıLmıstır. Sonuç lar yedinci bölümde tablolara dökülerek incelenmiştir.

The tallness of a building is a matter of a person's or community's circumstance and their consequent perception; therefore, a measurable definition of a tall building cannot be universally applied. From the structural engineer's point of view however, a tall building may be defined as one that, because of its height, is affected by lateral forces due to wind or earthquake actions to an extent that they play an important role in the structural design. The influence of these actions must therefore be considered from the very beginning of the design process. Tall towers and buildings have fascinated mankind from the beginning of civilization, their construction being initially for defence and subsequently for ecclesiastical purposes. The growth in modern tall building construction, however which began in the 1880s, has been largely for commercial and residential purposes. Tall commercial buildings are primarily a response to the demand by business activities to be as close to each other, and Co the city center, as possible, tehere by putting intense pressure on the available land space. Also, because they form distinctive landmarks, tall commercial buildings are frequently developed in city center as prestige symbols for corporate organizations. Further, the business and community, with its increasing mobility has fuelled a need for more, frequently high-rise, city center hotel accomodantions. The rapid growth of the urban population and the consequent pressure on limited space have considerably influenced city residential development. The high cost of land, the desire to avoid a continuous urban sprawl and the need to preserve important aqricultural production have all contributed to drive residential buildings upward. In some cities, for example. HongKong and Rio de Janerio, local topographical restrictions make tall buildings the only feasible solutions for housing needs. The feasibility and desirability of high-rise structures have always depended on the available materials, the level of construction technology, and the state of development of the services necessary for the use of the building. As a result, significant advances have occurred from time to time with the advent of a new material, construction facility, or form of service. Speed of erection is a vital factor in obtaining a return on the investment involved in such large-scale projects. Most tall buildings are constructed in conqested city sites, with difficult access; therefore careful planning and organization of the construction sequence become essential. The story-to-story uniformity of most multistory buildings encourages construction through repetitive operations and pref abrication techniques, progress in the ability to build tall has gone hand in hand with the development of more efficient equipment and improved methods of construction, such as slip-and flying- formwork, concrete pumping and the use of tower, climbing, and large mobile cranes. The architectural engineering solutions for such specialized buildings are therefore quite different from eachother. The office and commercial buildings are used larger span structural systems consistent with the space requirements for offices and other commercial functions; whereas the housing and apartment buildings use relatively smaller span structural systems consistent with residential room sizes. Although both reinforced concrete and structural steel were used for office buildings as well as residential buildings, the structural systems are quite different eachother. The office, commercial and residential buildings have also different structural systems, reflecting their differing functional requirements. In modern office buildings, the need to satisty the differing requirements of individual clients for floor space arrangements led to the provision of large column-free open areas to allow flexibility in planning. improved levels of services have frequently necessitated the devotion of entire floors to mechanical plant, but the spaces lost can often be utilized also to accomodote deep girders or trusses connecting the exterior and interior structural systems. The earlier heavy internal partitions and masonry cladding, with their contributions to the reserve of stifness and strength have largely given way to light demontable partitions and glass curtain walls. Forcing the basic structural alone to provide the required strength and stiffness against both vertical and lateral loads. A commercial building that has influenced structural form is the large entrances and open lobby areas at ground level, the multistory atriums, and the high-level restaurants and viewing galleries that may require more extensive elavator systems. A residential building's basic functional requirement is the provision of self contained individual dwelling units, separated by substantial partitions that provide adequate fire and acoustic insulation. Because the partitions are repeated from story to story, modern designs have utilized them in a structural capacity, leading to the shear wall or inf illed-frame forms of construction. Flat-plate, reinforced concrete slab construction therefore become the most accepted floor systems for residential building; whereas beams and joists or waffle slab were used more frequently for office and commercial floors. Morever a high-rise building may be a single-use one or a multi-use one. For multi-use building it is necessary to develop structural system that respond effectively to the need of the different functions. In developing such systems, the first step is to select appropriate structural material. The selection process must start with the most commonly used structural materials (steel or Reinforced Concrete, both normal and lightweight; composite systems and so forth. ). A multi-use building is much more complex architecturally because of the different requirements for each use. For example, the maximum building with required tor an efficient office space; and the optimum column spacings for a residential building, its plan flexibility, are distict.ly different from those for commercial or office buildings. Performance of the building must be satisfactory for which two criteria must be satisfied - Strength and stability - Servicieability The two primary types of vertical load-resisting elements of tall building are columns and walls, the latter acting either independently as shear walls or in assemblies as shear wall cores. The building function will lead naturally to the provision of walls to divide and enclose space and of cores to cantain and convey services such as elevators. Columns will be provided, in other wise unsupported regions, to transmit gravity loads and, in some types of structure, horizontal.loads also. Columns may also serve architecturally like tubular structures, for example, facade mullions. The inevitable primary function of the structural elements is to resist the gravity loading from the weight of the building. The gravity load on the columns increases xxx down the height of a building, the weight of columns per unit area increases approximately linearly with the building height. The highly probable second function of the vertical structural elements is to resist also the parasitic load caused by wind and earthquakes, whose magnitudes will be obtained from National BuiLding Codes or wind tunnel studies. The bending moments on the building caused by these lateral forces increase with at least the square of the height, and their effects will become progressively more important as the building height increases. An entire design team, including the architect, structural engineer and services engineer, should collaborate to agree on a form of structure to satisfy their respective requirements of function safety and serviceability and servicing. A compromise between conflicting demands will be almost inevitable. In high-rise buildings lateral loads that are called wind loading and Earthquake loading are very important to provide lateral resistance. Lateral load resisting units and from any or combinations of them - Rigid-frame structures - inf illed-f rame structures - Shear wall structures - Coupled shear wall structures - Shearwall -frame structures - Tubular structures "Framed and Bundled- tube structures for reinf orced-concrete buildings, and Braced-tube structure for steel building" One of these structural systems is important for lateral load resisting of a high-rise building. The basic design philosophy in this form has been to place as much as possible of the load-carrying material around the external periphery of the buildings to maximize the flexural rigidity of the cross section. The frame panels are formed by closely spaced perimeter columns that are connected by deep spandrel beams at each floor level, referred to as the f ramed tuse system, is being used increasingly for high- rise structures because of its inherent advantages in resisting lateral loads. Xlll In this study, in the first three chapter high-rise buildings, the vertical and lateral loads and materials have been categorized. In the fourth chapter, structural systems have been analyzed. In the fifth chapter, structural behavior of framed-tube structures have been analyzed. In the sixth chapter, framed-tube system have been analyzed with structuraJ anajysis programme. In the seven chapter the results are discussed.