23 katlı betonarme bir yapının projelendirilmesi

Abstract

Yüksek lisans tezi olarak, Prof. Dr. Metin AYDOÖAN danışmanlığında 23 katlı betonarme bir yapı projelendirilmiştir. Söz konsu bina 1. deprem bölgesinde olup, otopark veya depo olarak kullanılacak 3 bodrum kattan, ticari amaçlı kullanılacak 1 zemin kattan ve büro olarak kullanılcak 19 normal kattan oluşmaktadır. Yapıda malzeme olarak; BS25 beton, BCIH donatı (etriyeler için B(|jJ) kullanılmaktadır. Yapının taşıyıcı sistemi lineer elastik malzemeden yapıldığı varsayılan perdeli - çerçeveli taşıyıcı sistemdir. Kat yükseklikleri bodrum katında 3.00 m, zemin katta 5.00 m ve normal katlarda 3.00 m şeklindedir. Kat döşemeleri, çekirdek ve çekirdek çevresinde, çift doğrultuda ve tek doğrultuda çalışan normal betonarme döşemeler, diğer bölgelerde kaset döşemeler tipindedir. Taşıyıcı sistemin hesabında ölü yükler, hareketli yükler ve deprem etkisi gözönüne alınmıştır. Hesapların yapılışında, yük aktarma sırasına uygun olarak, döşemelerden temele doğru bir sıra izlenmiştir. Kesit tesirlerinin hesaplanmasında, depremli durum ile depremsiz durumda elde edilen etkilerin süperpozisyonu yapılmıştır. Yapının statik hesabında, düşey yükler için elverişssiz akslar alınarak en elverişssiz yükleme durumları (dolu - boş) incelenmiştir. Statik çözüm SAP90 yapı analizi programının 5.40 versiyonu ile yapılmıştır. Yapının yatay yükler karşısında hesabı (deprem hesabı), SAP90 yapı analizi programının 5.40 versiyonu ile, üç boyutlu dinamik analiz kullanılarak 1. doğal peryodun bulunması, yapının kat hizalarına gelen deprem yüklerinin elde edilmesi ve bu yükler altında yine SAP90 ile üç boyutlu çözüm yapılması aşamalarıyla gerçekleşmektedir. Binanın taşıyıcı elemanlarının betonarme hesabı taşıma gücü yöntemi ve yeni deprem yönetmeliği şartlarına uygun olarak yapılmıştır. XV Zemin emniyet gerilmesi 300 kN/m2 'dir. Temel sistemi kirişssiz radye temel sistemi olarak seçilmiştir. Binanın SAP90 dataları ve çizimleri, ilgili bölümlerde ve EK'lerde verilmiştir.

The design project of a multi - storey reinforced concrete building presented herein is a master thesis, under administration of Prof. Dr. Metin AYDO?AN. The building under consideration is twenty-three stories high with floor area of 30.60 meters by 30.60 meters. The building consist of three basements, ground floor as a store floor for shopping centre or showroom and nineteen official stories, which are designed as residences. Building is supposed to be constructed in the first degree seismic zone according to the map appended to the "Specification for the buildings to be built in natural disaster areas". For the structural system of the building a tube-frame wall system is chosen. BS25 and Still are chosen as materials of structural system. The loads on structure consist of dead loads and live loads. Design loads are taken from Turkish Standard 498 (TS498) for live loads and dead loads. Live loads is the loading to be carried by the structure, including impact of the dynamic effect of the application of the live load. Dead loads contain the weight of the structure itself. As mentioned in the Chapter 1 the aim of thesis is the design of a twenty-three stories high building. The design starts with slab calculations. The slab calculations are presented in Chapter 2. The slab is taken and designed as plates and casette plates. The slab thickness is first determined in a such a way no deflection calculation is necessary, then the load analysis is done for each different slab (store, showroom, official floors, roof floor). After determined the loads the design calculations are performed by the procedure specified in reference, [2]. At the Chapter 3 the loads were transferred from floors to the beams in two groups for dead loads and as well as live loads. So loads of beam for all floors calculated. xvn At the Chapter 4 normal forces in columns are calculated for each floor by using beam loads which are found in chapter two. Afterwards slab loads are increased by multiplying with appropriate load factors. Later according to the TS500 cross sectional dimensions of the slabs are chosen to use in structural calculations. At the Chapter 5 the structural calculations of the building for vertical forces is made using the version of 5.40 of the SAP90 (structural analysis program ). After selection of critical axes of building, these axes were solved critical loading positions of axes' frames with SAP90 to obtain cross sectional effects. At the Chapter 6 the critic cross section effects due to the lateral earthquake forces were calculated using dynamic method. According to this method, the system is made of linear elastic material and masses are concentrated at story levels called nodes at the middle of every storey. Gravity loading consists of dead loading, which can be predicted with reasonable accuracy. Live loads are estimated based on experience and field surveys, and given in the standards. The probability of not all parts of a floor supported by a beam, and of not all floors supported by a column, being subjected to the full life loading simultaneously, is taken care by reductions in the beam loading and in the column loading, respectively, in accordance with various formulas. It is sometimes necessary to consider also the effects of construction loads. The usefulness of shearwalls in the structural planning of multi-storey buildings has long been recognised. When shearwalls are situated in proper positions in a building, they can be very efficient in resisting lateral loads originating from earthquakes. A large portion of the lateral load on a building, the horizontal shear force resulting from the load, are often assigned to such structural elements called shearwalls. The name is unfortunate, for only rarely is the critical mode of resistance associated with shear. Multi-storey buildings have become taller and become slender in time and with this trend the analysis of shear walls emerges as a critical design item. More often than not, shear walls are pierced by numerous opening. The structural engineer is fortunate if these are arranged in a systematic pattern. xvin Earthquake loading is a result of the dynamic response of the building to the shaking of the ground. Estimates of the loading account for the properties of the structure and record of earthquakes in the region. For unexceptionally high building with unexceptional structural arrangements an equivalent lateral force is recommended. In doing this, the loading is estimated on the basis of a simple approximation of the fundamental period of the structure. Its dead load, the anticipated ground acceleration or velocity, and other factors relating to the soil site conditions at the structural type and the importance of the building. The method gives the value of the maximum horizontal base shear, which is then distributed as an equivalent lateral load over the height of the building at the story levels so that static analysis can be performed. During an earthquake, ground motions occur in a random fashion in all directions. Measurements of horizontal and vertical ground accelerations, made as a function of time, have indicated that the ground accelerations can be considerable. When a structure is subjected to ground motions in an earthquake, it responds in a vibratory mode. When the structure is behaving elastically, the maximum response of acceleration will depend on the structure's natural period of vibration. Dynamic analysis of structures responding elastically to typical earthquake records have indicated the order of response accelerations Sa and are plotted as a function of the natural period of vibration of the structure and the magnitude of the damping, which is expressed as a percentage of the critical viscous damping. The curves are idealised from the more irregular actual curves. It is seen that in some range of periods, the maximum response acceleration of the structures with a very small period approaches the maximum ground acceleration. The maximum response acceleration of structures with large periods of vibration may experience little more than the maximum ground acceleration. An increase in damping will always result in decrease acceleration. The maximum inertia loads on the simple structure during the earthquake may be obtained by multiplying the acceleration by the mass. Design seismic loading recommended by building codes is in the form of static lateral loading. Dynamic analyses of structures, responding elastically to xix ground motions recorded during severe earthquakes, have shown that the theoretical responsive inertia loads may be much greater than the static design lateral loads recommended by such codes. Although this difference is too large to be reconciled by safety factors in design, it is well known that structures designed to the lateral loads of codes have survived severe earthquakes. It is evident that it would be uneconomical to design a structure to withstand the greatest likely earthquakes without damage. Buildings should be able to resist minor earthquakes without damage, to resist moderate earthquakes without structural damage but with some non-structural damage, and to resist major earthquakes without collapse but some structural and non-structural damage. Hence the possibility of damage is accepted, but not loss of life. The code objective is to have structures that will behave elastically under earthquakes that can be expected to occur more than once in the life of the building; the structures, moreover, should be able to survive without collapse the major earthquake that might occur during the useful life of building. To avoid collapse during the major earthquake, members must be ductile enough to absorb and dissipate by postelastic deformations. The order of ductility involved may be associated with very large permanent deformations. Thus although the structure should not collapse, the resulting damage might be beyond repair, and the structure might become a total economic loss. According to the calculations by using SAP90, the lateral loads effecting on each storey at the level of the floors were determined by accepting the C=l, then the flexural rigidities of columns and beams were calculated and given in tables. After determination of flexural rigidities the load carrying system were separated into system in X and Y directions. The tie beam's coefficient of distribution were determined separately depending on rigidity of the tie beams according to the type of the tie beam, either connecting two shear walls or connecting a shear wall with column. In tie beams of a shear wall and column, a Active tie beam was used. After determination tie beam's coefficient of distribution in every storey, the shear rigidities of Active frames were calculated for last storey, first storey and intermediate stories depending on the tie beam coefficient of distribution, then as iDfj values. xx According to the analysis of Muto, the continuity equations coefficients were obtained by Fj and fj, where Fi is equal to the one by the sum of column and fictive frame's rigidities at i.th storey. After writing the continuity equations in every storey the Xj unknowns were found out by solving the trio-diagonal system of simultaneous equations by gauss elimination procedure. By help Of Xj values total shear forces for every storey were determined, shown in the tables as IT values. The relative and total displacements of every stories were obtained by dividing total shear forces by total rigidities of every storey. The special angular frequency of the building for the first ordinary mode was found by w2=Iqi*di/Xmi*di formulas and special cycle for the first ordinary mode was found T=27t/w, the new "A" coefficient was found by A=Ao*K*S*I, all the previous values were multiplied by new "A" factor. The beam's moments found by using Mi,0 and Mj,u moments. The column's shear forces and the shear wall's moments were found by distributing the total values of each storey in proportion to their rigidity. The column's down and up moments were found by using SAP90. According to this analysis in the column-beam connections, these moments distributed respected to beam's rigidities. Of course, it is necessary to consider either earthquake loading and wind effects. It was considers unnecessary to make calculations for wind loading that is similar to that for earthquake forces. At the seventh chapter, the cross section effects of the beams determined from earthquake loads in chapter four and from vertical static loads in chapter five were superimposed. The superposition were made according to the code TS500 as G+Q+E with 1.4*G+1.6*Q. The values of the most inconvenient case were chosen finally and reinforced concrete calculations were made according to the code TS500 in chapter eight. The reinforced concrete calculations were made in two steps. At first, the beams were equipped length wisely according to the bending moment and afterwards transversally according to the shear forces. The columns and shear-walls were determined as well as. xxi The vertical elements of the first storey were designed according to the bending moments in two directions with the all forms of normal forces superimposed. Each normal force determined from the superposition, was chosen. The reinforced concrete calculations were made according to TS500 with the biggest effects. At the nineth chapter the foundation system was chosen and calculated. The foundation was chosen as general mat footing with beams continuous beams. The ground tensions was controlled not to exceed the limit stress of the ground under vertical normal forces of the columns and the shear-walls. In this calculation the general mat foundation was considered rigid. The height of the foundation beams was determinate according to the biggest shear force brought out, not to require the shear force calculations in the beams. The static calculations of the foundation plates were performed by considering them as floor plates. The beams of the general mat were statically calculated by considering them as floor beams. The continuous beams out of the general mat area were not statically calculated as the beams of general mat. The beams were considered flexible and the stresses of the ground were determined. The dynamic and static analysis due to the effect of horizontal forces was performed by the program SAP90. The coordinate and loads were entered in the programs according to chosen axis coordinate system. A floor diaphragm is modelled as a rigid horizontal plane parallel to the global X-Y plane, so that all points on any one floor diaphragm cannot displace relative to each other in the X-Y plane. Typically, each floor diaphragm is established by a joint in the plane of the diaphragm called the master joint of the diaphragm. The location of the master joint on each floor is arbitrary by the user. All the other joints that exist on the diaphragm are connected to the master node by rigid links, and their displacements are dependent upon the displacement of the master joint. The joints are called depended joints. This option is very useful in the lateral dynamic analysis of building type structures. Lumping the story masses at the centre of mass (with an associated mass moment of inertia about the Z-axis) will result in a very small eigenvalue problem. xxii So we solved the system and found cross sectional effects. As a result, a multi-storey building is designed, it's structural system is solved using SAP90 (Structural Analysis Program) and all members are reinforced according to the new Turkish Earthquake Codes (2 of September in 1997)[5].