Use of shotcreted panels for strengthening and construction of low rise buildings
Use of shotcreted panels for strengthening and construction of low rise buildings
Dosyalar
Tarih
2000
Yazarlar
Mourtaja, Waiel
Süreli Yayın başlığı
Süreli Yayın ISSN
Cilt Başlığı
Yayınevi
Fen Bilimleri Enstitüsü
Institute of Science and Technology
Institute of Science and Technology
Özet
Doktora tezi olarak sunulan bu çalışmada, püskürtme betonla yerinde üretilmiş panellerden oluşturulan yapıların deprem etkisindeki davranışları incelenmiştir. Birinci bölümde, püskürtme panellerinin uygulamadaki kullanım kolaylığı ve elverişli yönleri tanımlanarak, bir betonarme panelin kayma gerilmeleri altındaki davranışlarını içeren önceki çalışmalar taranmış ve bir betonarme panelin kayma gerilmeleri ile kayma şekildeğiştirmeleri arasındaki ilişkiyi elde eden mevcut tekniklerin eleştirisi yapılmiştır. İkinci Bölümde, püskürtme panelinin içindeki çelik çubukların çekme mukavemeti, püskürtme betonun basınç gerilme şekildeğiştirme arasındaki bağlantı sargılı ve sargısız haller için deneysel olarak elde edilmiştir. Üçüncü Bölümde, basit kayma etkisindeki bir panelde yüklemenin çevreye dağıtılmasının önemi, Lusas programı kullanılarak ve betonarmenin nonlineer analizi ile belirlendi. Daha sonra, yapılan pilot testin olumlu sonuç vermesiyle yeni bir basit kayma testi tekniği geliştirildi ve bu teknik püskürtme panellerinin kayma gerilmesi ve kayma şekildeğiştirmesi ilişkisini elde etmek için kullanıldı. Dördüncü Bölümde, XA ölçeğindeki Hasarlı bir betonarme çerçeve özel püskürtme beton panellerle güçlendirme yapıldı, bu güçlendirme işlemi üç farklı numune için uygulandı ve püskürtme panel takviyeli betonarme çerçevenin yatay yük altındaki rijidliği, mukavemeti ve deformasyonu tuğla takviyeli benzer bir betonarme çerçeveyle önceki test yardımıyla karşılaştırıldı. Beşinci bölümde, lA ölçeğindeki 3-Boyutlu bir numune püskürtme beton panelleri kullanılarak laboratuvarda gerçek yapımn bir kopyası olarak inşa edildi. Panellerin hafifliğinin avantajı binanın ağırlığım yarıya indirdi. Bu xı numunenin yatay monoton yük altında planlanan yükten on kat fazlasını taşıyabileceği gösterildi. Altıncı bölümde, öncelikle, 1997 de Hus Thomas tarafından sabit-açılı kafes model algoritmasına bağlı olarak hazırlanmış Visual Basic programı geliştirilmiştir.Daha sonra, geliştirilen bu program ile Lusas programı birlikte kullanılarak dördüncü bölümde yapılan basit kayma testinin doğruluk derecesi anlaşılmaya çalışılmıştır. Ayrıca, sonlu elemanlar modeliyle oluşturulan mevcut betonarme yapılar sunulduktan sonra özel olarak hazırlanan Visual Basic Mourtaja programı 3-Boyutlu numunenin ve betonarme çerçevenin lineer olmayan davranışlarını tahmin etmek için kullanıldı. Yedinci bölümde elde edilen sonuçlar verildi.
In this research the behavior of shotcreted panel buildings subjected to lateral loadings has been investigated. In Chapter 1, the advantages and usage of shotcreted panels in practice has been described, and a literature survey on the softened behavior of a reinforced concrete panel subjected to shear stress has been summarized. And the existing testing technique for obtaining the shear stress-shear strain relationship of a reinforced concrete panel has been criticized. In Chapter 2, the shotcrete compressive stress-strain relationship with and without spiral confinement, tensile strength of shotcrete, and yield strength of the steel bars of the shotcreted panel were experimentally obtained. In Chapter 3, the importance of distributing the total applied load around the panel edges in the pure shear test has been theoretically investigated by nonlinear analysis of RC panel under pure shear using LUSAS program. Then a newly proposed pure shear testing technique verified by pilot test, were utilized to obtain the shear stress-shear strain relationship of the shotcreted panels. In Chapter 4, lA scale reinforced concrete frame subjected to displacement reversal has been strengthened by means of the special stotcreted panels. Three specimen were prepared, with different connection details between the shotcreted panel and the RC frame.And their responses against displacement reversals were compared with previous tests of the same frame with brick infill, to find out the differences in terms of stiffness, strength, and deformability. In Chapter 5, a three dimensional specimen with Vz scale has been constructed in the laboratory using the special shotcreted panels. The specimen is exactly a replica of the real structure which is under investigation. The light weight panels reduce the total weight of the structure roughly in half. And the monotonic xni lateral loadings indicates that ultimate load reached may be 10 times higher than the design load and all relative displacement requirements are perfectly satisfied. In Chapter 6, the pure shear test made in Chapter 4, were justified using both LUSAS program, and VISUAL BASIC program developed depending on the fixed-angle truss model algorithms proposed by Hus Thomas 1997. Previous aspects of modeling RC structures by FEM were presented, then a specially prepared VISUAL BASIC computer program named as MOURTAJA were used to predict the nonlinear behavior of shotcreted walls which were used later to build up the 3D specimen or to strengthen the damaged RC frame. The material nonlinearity in this program is taken into account by modifying the shear modulus of the all elements using a shear modulus reduction factor R. And the value of R is not constant, but it can be obtained depending on the shear strain value calculated from the linear analysis, and the shear stress - shear strain relationship of a shotcreted panel obtained from tests. ( see Figure 6. 14,and section 6.2. 1 ). In Chapter 7, the achieved conclusions were presented. And The major results achieved at the end of these experimental and theoretical works are as follows i. Shotcreted panels elements can be used either for strengthening purposes of existing damaged RC buildings or for constructing low rise buildings with relatively high safety against earthquake, ii. The degradation of shear stiffness of shocreted panels in nonlinear range can be predicted by a shear stress-shear strain depending reduction factor, iii. Shear degradation factor can be implemented into the finite element representation and better results can be achieved for the nonlinear behavior of shotcreted panels, iv. Computer programs developed both for the prediction of shear degradation factor and to linearise the problem can be used to have reliable theoretical solutions.
In this research the behavior of shotcreted panel buildings subjected to lateral loadings has been investigated. In Chapter 1, the advantages and usage of shotcreted panels in practice has been described, and a literature survey on the softened behavior of a reinforced concrete panel subjected to shear stress has been summarized. And the existing testing technique for obtaining the shear stress-shear strain relationship of a reinforced concrete panel has been criticized. In Chapter 2, the shotcrete compressive stress-strain relationship with and without spiral confinement, tensile strength of shotcrete, and yield strength of the steel bars of the shotcreted panel were experimentally obtained. In Chapter 3, the importance of distributing the total applied load around the panel edges in the pure shear test has been theoretically investigated by nonlinear analysis of RC panel under pure shear using LUSAS program. Then a newly proposed pure shear testing technique verified by pilot test, were utilized to obtain the shear stress-shear strain relationship of the shotcreted panels. In Chapter 4, lA scale reinforced concrete frame subjected to displacement reversal has been strengthened by means of the special stotcreted panels. Three specimen were prepared, with different connection details between the shotcreted panel and the RC frame.And their responses against displacement reversals were compared with previous tests of the same frame with brick infill, to find out the differences in terms of stiffness, strength, and deformability. In Chapter 5, a three dimensional specimen with Vz scale has been constructed in the laboratory using the special shotcreted panels. The specimen is exactly a replica of the real structure which is under investigation. The light weight panels reduce the total weight of the structure roughly in half. And the monotonic xni lateral loadings indicates that ultimate load reached may be 10 times higher than the design load and all relative displacement requirements are perfectly satisfied. In Chapter 6, the pure shear test made in Chapter 4, were justified using both LUSAS program, and VISUAL BASIC program developed depending on the fixed-angle truss model algorithms proposed by Hus Thomas 1997. Previous aspects of modeling RC structures by FEM were presented, then a specially prepared VISUAL BASIC computer program named as MOURTAJA were used to predict the nonlinear behavior of shotcreted walls which were used later to build up the 3D specimen or to strengthen the damaged RC frame. The material nonlinearity in this program is taken into account by modifying the shear modulus of the all elements using a shear modulus reduction factor R. And the value of R is not constant, but it can be obtained depending on the shear strain value calculated from the linear analysis, and the shear stress - shear strain relationship of a shotcreted panel obtained from tests. ( see Figure 6. 14,and section 6.2. 1 ). In Chapter 7, the achieved conclusions were presented. And The major results achieved at the end of these experimental and theoretical works are as follows i. Shotcreted panels elements can be used either for strengthening purposes of existing damaged RC buildings or for constructing low rise buildings with relatively high safety against earthquake, ii. The degradation of shear stiffness of shocreted panels in nonlinear range can be predicted by a shear stress-shear strain depending reduction factor, iii. Shear degradation factor can be implemented into the finite element representation and better results can be achieved for the nonlinear behavior of shotcreted panels, iv. Computer programs developed both for the prediction of shear degradation factor and to linearise the problem can be used to have reliable theoretical solutions.
Açıklama
Tez (Doktora) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2000
Thesis (Ph.D.) -- İstanbul Technical University, Institute of Science and Technology, 2000
Thesis (Ph.D.) -- İstanbul Technical University, Institute of Science and Technology, 2000