Çelik yapılarda dolgu duvar etkisinin doğrusal ve doğrusal olmayan analiz yöntemleriyle araştırılması = Investigation of infill wall effect in steel structures with linear and nonlinear analysis methods

Abstract

Çelik yapı sistemleri, son yıllarda sık tercih edilen yapı türlerindendir. Hem yüksek açıklıkların rahatlıkla geçilebilmesi, hem de sünek malzeme yapısından dolayı deprem bölgelerinde tercih edilmesi sebebi ile önemli bir yapı sistemi haline gelmiştir. Çelik yapı sistemlerinin özellikle ofis kısımlarında sıkça kullanılan dolgu duvarların yapı sistemine etkisi bu tez çalışmasında incelenmiştir. Dolgu duvarlar, mimari sebeplerden dolayı farklı tasarımlar ile yapılara uygulanmaktadır. Uygulama yapılırken dolgu duvarlar yapı modeline düşey yük olarak etkitilirken, yatay yük altında yapısal analizlere dahil edilmemektedir. Dolgu duvarların yapısal davranış üzerindeki etkisinin göz ardı edilmesi, deprem etkisi altındaki gerçek davranışının bilinmezliği anlamına gelmektedir. Önemli deprem bölgelerinden Sakarya'nın Akyazı ilçesinde yapılacak olan bir yapının, dolgu duvarlı, dolgu duvarsız, farklı yüksekliklerde lineer ve nonlineer analizlerinin incelendiği kombinasyonlar hazırlanmış ve grafikleri yorumlanmıştır. Bu yapıların eşdeğer deprem yükü altındaki periyotları, düzensizlikleri, taban kesme kuvvetleri, tepe noktası deplasmanları, yapı ağırlıkları karşılaştırılmıştır. Aynı bölgeden alınan zemin etüd değerleri kullanılarak, A tipi ve B tipi merkezi çaprazlı iki ana yapı baz alınarak farklı tasarım tiplerinde kombinasyonlar oluşturulmuştur. 5 m aks arasına sahip yapılar, 3 arakat ve çatı olacak şekilde tasarlanmıştır. A ve B ana bina yapılarında M, N ve O tipleri farklı zemin kat yüksekliklerini temsil ederken 1, 2, 3, X, Y, Z ve K tipleri farklı dolgu duvar tasarımını temsil eder. Diğer bir yandan ED, Eşdeğer deprem yükü yöntemi ile analiz edilen yapıları; PO ise pushover yöntemi ile analiz edilen yapıları temsil etmektedir. Bu şekilde farklı tasarımlara sahip 84 farklı binanın karşılaştırılması yapılmıştır. Çalışmada incelenen yapılar, SAP2000 programında üç boyutlu olarak modellenmiştir. Eşdeğer deprem yükü yöntemi ile yapının analizi yapılmış, pushover yöntemi ile yapının performansı incelenmiştir. Tüm yapılara gelen rüzgar, kar, kaplama gibi yükler sabit baz alınmış, yalnızca dolgu duvar etkisinin yapı davranışına olan etkisi incelenmiştir. Buna göre, dolgu duvar tasarımlarının yapı performansına etki ettiği ve dolgu duvarların yapı hesabına katılmasının elzem olduğu sonucuna varılmıştır.

In recent years, steel structural systems are one of the most preferred structure. It has become an important structural system because it can be used in smaller sections compared to reinforced concrete at high spans and is preferred in earthquake zones due to its ductile material structure. In this masters thesis, the effect of the partition walls, which are often used in the office parts of the steel structural system, on the structural system was examined. Partition walls are applied to buildings of various designs for architectural reasons. While partition walls are applied to the building model when used as a vertical load, they are not included in the structural analysis under horizontal loads. Neglecting the effects of partition walls on the structural behavior means that the actual behavior under earthquakes influence is not known. Partition walls have positive and negative effects on structures. However, the inclusion of only the horizontal loading of the panel walls in the structural system during the dissolution of the structural system means that some positive and negative behaviors that can occur in the structure are not explained to the structure system. Literature studies of previous research shows that partition walls have positive and negative contributions to the structure system. Some positive effects of partition walls on the structure are that the panel walls under the beam reduce the deflection of the corresponding beam, the pressure rod effect of the infill walls against lateral loads, the relative floor drifts of the buildings decrease and the pressure rod effect contributes to the energy absorption of the structures. However, partion walls are known to have negative effects such as: torsional irregularity, weak storey irregularity, soft storey irregularity, short pillar formation. Partition walls are often used in office areas of industrial buildings. From literature review, it is shown that there is no comprehensive investigations of effect of partition walls on steel structures. To fill this research gap, research was conducted as part of masters program to investigate the effects of partition walls on steel structures. According to ERBBT 2018, earthquake calculation methods are divided into two methods which are the linear and the non-linear calculation methods. The linear calculation methods are divided into three sub-methods which are equivalent earthquake load method, mode coupling method and linear calculation method in time history. Nonlinear calculation methods on the other hand are divided into three sub-methods which are incremental equivalent earthquake load method, incremental mode coupling method and nonlinear calculation methods in the time history. In this thesis, the earthquake characteristics of the strucutres were determined with the equivalent earthquake load method, and the performances of the structures were investigated with the incremental equivalent earthquake load method. The research areas Akyazı district of Sakarya, Turkey. This area is an important earthquake zones in the region. In this area, combinations of linear and nonlinear analyses of structures with and without partition walls at different heights were examined and the generated graphs of the structures were interpreted. The periods, irregularities, base shear forces, peak displacements, and weights of these structures under equivalent earthquake loads were compared. By using the soil survey values taken from the same area, combinations of different design types were created based on the two main structures with type A and type B central braces. The structures with 5 m axle spacing were designed to have 3 mezzanine floors and a roof. In A and B main building structures; M type represents structures with a ground floor height of 3 m, N type structures with a ground floor height of 4 m, and O type structures with a ground floor height of 5 m. Representing different partition wall designs; type 1 represents structures without partition walls, type 2 represent structures without partition walls only on the ground floor, and type 3 represent structures with all partition walls. Representing different partition wall designs; X-type structures with windows on 6-6 axis only on the ground floor, Y-type structures with windows on 1-1 and 6-6 axes on the ground floor, Z-type structures with windows on the A-A and 6-6 axes on the ground floor and K-type structures with windows on the A-A, 1-1, 6-6 axes in the ground floor. On the other hand, the structures analyzed by ED means Equivalent earthquake load method and PO represents the structures analyzed by the pushover method. In this way, 84 different buildings with different designs were compared. While the parameters such as partition wall condition, ground floor height, cross places varied during structural designs; other parameters such as building usage area, intermediate loads, material quality, snow load, wind load, coating type, ground values, building importance coefficient, building usage class, building height class, load combinations were constant. Dimensioning of the structures, wind and snow calculations were made according to TS498 principles. No cross-sectional changes were made according to different conditions in the parameters of stress, displacement and cross-section conditions. The structures examined in the study were modeled in three dimensions in the SAP2000 program. All structures were analyzed with the finite element method and the analysis results were compared in the light of the data obtained from the SAP2000 program. First of all, equivalent earthquake load calculations were made for the A and B type structures, which were taken as reference for the structures examined in the study. Accordingly, the dominant periods of the structures, the base shear forces acting in the X and Y directions, the irregularities, the displacements of the vertex and the weights of the structures were calculated by affecting the ground values taken as fixed in the program. Accordingly, it has been observed that the apex displacements of the structures where partition walls are used more frequently decrease and the base shear forces on the structures increase. In addition to these results, it has been determined that the structure vary with parameters such as the height of the ground floor and the condition of the cross system, independent of the partition wall. Secondly, performance analyzes were made with the incremental equivalent earthquake load method for the A and B type reference structures. The capacity curves of the structures were calculated and the plastic hinge and collapse zones were found. Lateral loads were given to the structures with certain steps and plastic deformations of the structures were followed according to the state of the partition wall. Accordingly, it has been determined that the stuctures with denser partition wall behave more ductilely and have less lateral displacements than the buildings with less partition wall. It is seen that structures with fully partition walls begin to plastic hinge earlier than structures without partition walls, and their failure displacements are lower. Accordingly, it has been observed that different partition wall designs have positive or negative effects on the structural performance. It has been determined that partition walls have an effect on parameters such as base shear force, relative storey drifts, building weights, building periods, plastic hinge points and building capacity. It was concluded that it is essential to include partition walls in the construction calculation.