Çok katlı bir yapının yatay ve düşey yükler altında projelendirilmesi

Abstract

Yüksek lisans tezi olarak, Doç-Dr.Zeki HASGÜR yönetiminde 17 katlı betonarme bir yapı projelendirilmiştir. Söz konusu yapı, 1 bodrum kat,l mağaza katı ve 15 konut amaçlı normal kattan oluşmaktadır. Yapıda malzeme olarak, beton BS20, donatı çeliği, döşemelerde BCI diğer kısımlarda BCIIIa kullanılmıştır. Yapının taşıyıcı sistemi lineer elastik malzemeden yapılmış perde -çerçeve sistemidir. Kat yükseklikleri bodrum katında 2,50 zemin katta 5,00 m ve normal katlarda 3,00 m olup temel alanı 840 m2 d ir. Yapının duvarlarında, iç kısımlarda yarım, dış kısımlarda tam tuğla kullanılmıştır. Çatısı marsilya tipi kiremitle kaplı olarak tasarlanmıştır. Zemin emniyet gerilmesi 28 t/m2 dir. Temel sistemi kirişli radye olarak hesaplanmıştır.

For master thesis, under the administration of Doc- Dr. Zeki HASGüR, member of the department of Reinforced Concrete, a high- rise building is designed. The building under consideration is seventeen stories high with floor area of 15,00 meters by 4-0,20 meters. The building consists of a basement and ground floor as store floor- shopping center and fifteen normal stories. Loads and beams : 1. Weight of the beam 2. Load of the wall 3. Weight of the slab 4. Live load on slab Load on beams are transferred from slabs. Short span qk = q x Lk qxLk 2 1 Long span qu = x ( - > 3 3 2m2 A frame- shear wall system is choosen as structural system and BS20, STIII are as materials, the behavior of the system is supposed elastic. tx Design computations start from the floors and go towards the foundation according to the flow of the loads. In the computation for horizontal forces do earthquake inf luances we have been guided by the above specifications about disaster zones. The calculations of the building according to horizontal forces were made in accordance with the procedure specified in the referances C83-C53. This method, given in the refer ance C83 is half dynamic method.According to this, the system is made of linear elastic material and the masses were concentrated at certain points called nodes at the middle of every storey. First of all, the leteral loads effecting on each storey at the lavel of the floors were determined by accepting the C=l, then the fluxural rigidites of columns and beams were calculated and given in tables. After determination of fluxural rigidites the carrier system were separeted into axes at X and Y directions. The tie beam's coefficient of distribution were determin ed seperately 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 a column. In tie beams a shear wall and column, If value also call ed as the fictive tie beam was used instead of tie beam moment of inertia. After determination tie beam's coeficent of distri bution in every storey, the shear rigidities of fictive frames were calculatedfor last storey, first storey and intermediate stories depending on the tie beam coeficient of distribution, then total of fictive rigidities in every storey were given in table as 2D f,i values. The continuity equations coefficients were abtained by «Fi» and «fi», where Fi is equal to the divide of the one by the sum of columns and fictive frames' s rigidities at i.th storey. After writing the continuity equations in every storey the Xi unknowns were found out by solving the tri-diegonal system of simultaneous equations (Gauss elimination procedure). By help of Xi values total shear forces effect on every storey were determined, shown in the tables as ZT values. The relative and total displacements of every s tor eyes were obtained by dividing total shear forces by total rigidities of every storey. The special angular frequancy of the building for the first ordinary mode was found by w2=2qi.di/Emi.di2 formu laes and speci al cycle for the first ordinary mode was found T=2ji/w, the new «C» coefficent was found by C = Co.K.S.I, all the previous values were multiplied by new «C» factor. The beam's moments found by help of Mi, o and Mi,u moments. The columns' s shear forces and the shear wall's moments were found by distributing the total values of each storey respect to their rigidity. The columns' s down and up moments were found by MUTO method's formu laes depend on yi values. In the colum-beam connections these moments were distributed respect to beam's rigidities. Of course, i t is necessary to consider either earthquake load ing and wind effects. It was considered unnecessary to make cal culations for wind loading that is similar to that for earthquake forces. Static calculations of the beams under vertical loads were made by cross method for various inconvenient loading positions and the most inconvenient effects were found.Then, the vertical effects were superimposed with lateral ones. A t the second step the reinfoced concrete colculations were made according to references C1S3,E133. At the seventh chapter, the columns and shear walls were designed. At the first step the leteral and vertical effects were super imposed, then reinforced concrete calculations of coumns and shear walls were done according to references £13, CIS 3 The system of foundation was chosen as general mat footing with beams. xl After calculating the effects acting on the base of construc tion, the ground tension was controlled. For dimensioning the found ation's beams, the beam which was encountering the maximum effect was taken into consideration. Allowable soil pressure is 28 ton per m 2. The thickness of the foundations is 1,50 meter. The static calculations of the foundation was performed by considering, it is as a floor plate. The foundation beams were solved with cross method in continuous beams. At the ninth chapter the ladder were designed as a plate system ladder. The load analysis were made in two parts of the ladder. The static and reinforced concrete calculations of these parts were g iven. It is observed that for such as 17 storey height building frame- shear wall system appropriate. If it is insisted on a tray frame system it would be to force too much with too large column sections at bottom floors. These section would cause to loose too much space and would give much trouble with functionnary of the building. XII. CONCLUSIONS AND SUGGESTIONS The optimum design high-rise buildings should stafisfy architectural and engineering performance criteria according to codes and local regulations at the most economical cost. The large variety of construction materials and structural system makes the task of obtaining the optimum solution, diffucult for the designers. An efficent and economical structural system can evolve only through understanding of the singificant factors affect ing the design of a tall building. Several structural systems that have been utilized in the past twenty- five years briefly outlined. Frame buildings, which rely on predominant Vierendeel frame actions, are suitable only up to about 10-SO stories. But currently, this frame system is generally used for low- rise buildings in the 4 to 6-storey range. Structural systems which derive all their lateral stiffness and strength from only shear walls feasible up to about SO to 4-0 stories. For higher structures, the wind stresses tend to control the design and, therefore, the increased thicness of the shear walls would reduce the core and structural efficiencies. Frame- shear wall interacting systems were a logical extension of the shear wall system which was generally created by the addition of shear frames the fascia of the shear wall- frame interaction brought substantial stuctural benefits in terms of lateral load resistance and strenght. In this system, the fascia plane frame parallel to the direction of the lateral load was considered in the interaction with the core walls. A study of some recent efficient buildings indicates that the frame stiffness is large enough to reduce the free contilever deflection of the wall to about one-third its value after interaction, XIII. Since the interaction involves two subsystem,, studies for optimum combination should be performed. In general, shear walls should be positioned for large gravity load tributary areas which not only reduce the possibility of uplift, but also increese the capacity to resist wind over turning moments because of the increase permitted in the ' stresses when wind forces are considered. In this work a seventeen storey high is considered as frame- shear wall structural system which have a maximum economy and performance limitation. Foundation problems become more important with increasing height of the building. For this reason it is necessary to make investigation about the properties of foundation soil and construction site.