A Study of Relationship between Seismic Provision and Progressive Collapse Resistance
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Date
2018-12
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Addis Ababa University
Abstract
Progressive collapse is known to be the cause of most catastrophic structural failures around the world. Recent acts of terrorism including the destruction of the World Trade Center demand for methods to improve behavior of structures under these abnormal events. Design of structures against progressive collapse has not been an integral part of structural design. However, some codes such the GSA and UFC guideline have detail requirements to reduce the likelihood of progressive collapse. Effect of seismic provision in progressive collapse resistance was not mentioned in this guidelines.
Hence, one of this thesis aim was to investigating the relationship between seismic provision and progressive collapse resistance of RC framed structures. To achieve this, a six-story regular RC framed models were designed according to ES EN 1998:1-2015. Ground accelerations of 0.15g with low, medium and high ductility classes were used. Moreover, a deficient structure with insufficient development length and lap splice at connection was also considered. Progressive collapse analysis was carried out on the four structures by considering four different column loss scenarios. Nonlinear static (pushdown) analysis were adopted in all 16 cases of progressive collapse assessment based on GSA 2013 guidelines.
It was concluded that the progressive collapse resistance of a structure is influenced heavily by the design ductility. Buildings designed for lower ductility have higher yield loads but undergo lower deformations before collapse. On the other hand, buildings designed for higher ductility yield at lower loads but they undergo greater deformations and absorbs more energy to resist collapse. However, based on the progressive collapse analysis low ductility design is the one that perform good in progressive collapse with maximum load factor when compared with medium and high ductility design.
The other aim of this thesis was to study the development of CAA and CA analytical model for beam column sub-assemblage, and to investigate application of CAA into alternative path design. It was found that the analytical model was quite similar with experimental result and it shows that reinforced concrete beams can be modeled as rigid rectangular blocks between the hinge locations to determine CAA and CA capacity. In addition, with adequate boundary restraints and shear strength, CAA found to be applicable into the design against progressive collapse.
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Seismic Provision, Progressive Collapse Resistance