Doctor of Philosophy, The Ohio State University, 2017, Civil Engineering

Progressive collapse is partial or complete collapse of a building, which is triggered by the sudden loss of load-bearing structural elements such as columns and walls. Many computational research studies have been conducted to investigate the progressive collapse mechanism and validation of current design guidelines. However, very few full-scale experiments have been conducted to produce experimental evidence and to evaluate and validate theoretical models. In this dissertation, the progressive collapse performance of masonry wall structures and a steel structure with infill walls have been investigated. Two existing wall structure buildings on the Ohio State University campus (Blackburn House and Nosker House) were tested by physically removing four exterior load-bearing walls consecutively. The mechanical response, including deflection of beams and strain variation in reinforced steel and CMU walls due to the sudden loss of walls, were measured by displacement sensors and strain gauges. Two-dimensional and three-dimensional models were developed using the structural analysis program SAP2000 to simulate the response of test buildings. The calculated response was compared with the experimental data measured in the field. The progressive collapse risk probabilities are evaluated by using current guidelines, and recommendations are made based on the numerical and experimental data generated in this research. New demand capacity ratio acceptance criteria are proposed for progressive collapse evaluation of masonry wall structures. A load increase factor is proposed to perform alternate load path analysis of masonry wall structures. The steel frame building with unreinforced masonry infill walls, Haskett Hall, was previously tested by removing a first story column. Progressive collapse performance of the structure and the contribution of infill walls are examined by modeling the masonry infill walls in the structural analysis program. Based on the numerical simulatio (open full item for complete abstract)

Committee: Halil Sezen (Advisor); Alper Yilmaz (Committee Member); Trunjit Butalia (Committee Member); Chen Qian (Committee Member) Subjects: Civil Engineering

Master of Science, The Ohio State University, 2010, Civil Engineering

Progressive collapse has been of an increasing concern in the structural engineering community, especially since the collapse of the World Trade Center towers in 2001. As a result of increasing catastrophic events in recent years, the prevention of progressive collapse is becoming a requirement in building design and analysis. A large number of studies have been performed to improve the design of the building against progressive collapse and to evaluate the progressive collapse potential of existing and new buildings by using computer programs and analytical tools. However, experimental evidence is still necessary to validate the computational analysis tools to better simulate the progressive collapse of structures. In this research, both experimental and analytical assessments of the progressive collapse potential of existing buildings were conducted. Two actual steel frame buildings, the Ohio Union building in Columbus, Ohio and the Bankers Life and Casualty Company (BLCC) building in Northbrook, Illinois were tested by physically removing four first-story columns prior to buildings' scheduled demolition. During the field tests the changes in column axial forces were measured, and the recorded strains were compared with the analysis results from computer models. A commercially available computer program, SAP2000 was used to model and analyze the test buildings, following the General Services Administration guidelines (GSA, 2003). Two-dimensional (2-D) as well as three-dimensional (3-D) models of each building were developed to analyze and compare the progressive collapse response. Also, two different analysis procedures were evaluated for their effectiveness in modeling progressive collapse scenarios; linear static and nonlinear dynamic procedures. The measured strain data compared relatively well with the analysis results of SAP2000. In particular, 3-D model was more accurate than 2-D model, because 3-D models can account for 3-D effects as well as avoid overly (open full item for complete abstract)

Committee: Halil Sezen PhD (Advisor); Hojjat Adeli PhD (Committee Member); Shive Chaturvedi PhD (Committee Member) Subjects: Civil Engineering

Master of Science, University of Akron, 2006, Civil Engineering

Metal bar gratings have been used in engineering and architectural applications for more than 80 years. Current design provisions are based on the allowable stress design philosophy using a simple mechanics approach for engineering analysis. Previous research and field experience with bar gratings has shown that the present design procedure is somewhat over-conservative, possibly resulting in uneconomical design of the gratings. There is a need to examine the behavior and current design approach of riveted steel bar gratings due to improvements in design methodologies, as well as market pressure from new materials and forms of gratings. Development of finite element software has made the building and processing of models easy and efficient. The ability to make rapid changes to the models has made the use of the finite element method for analyzing and studying the behavior of the metal bar gratings possible. This study involved the testing of heavy duty riveted and welded metal bar gratings. Finite element models were developed for riveted gratings using ANSYS 9.0. Linear analysis was performed on the models developed for design loads. Nonlinear analysis was performed, and incorporated both geometric and material nonlinearities to find the collapse load of the grates. Deflections obtained from the lab tests were compared to the results obtained from the finite element analysis to judge the accuracy of the models. Design recommendations were developed.

Committee: Craig Menzemer (Advisor) Subjects: Engineering, Civil