Browsing by Author "Akalp, Selahattin."

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    An approximate method for real time health monitoring and damage asessment of mind-to-high rise reinforced concrete buildings
    (Thesis (Ph.D.) - Bogazici University. Institute for Graduate Studies in Science and Engineering, 2022., 2022) Akalp, Selahattin.; Yalçın, Cem.
    Two separate methods are proposed and evaluated in this study for the structural health monitoring and damage detection of mid -to-high rise reinforced concrete buildings. The first method discussed herein, aims to predict the response of the structure at non-instrumented floors. A numerical structural model of the real-life structure is constructed and the modal response quantities are retrieved. The measured mode shapes of the real structure are considered as linear combination of the calculated mode shapes of the numerical model. For each mode shape to be superimposed, a weighting coefficient is obtained through minimizing the error between the actual and superimposed mode shapes and the final response is estimated by using the relation between the physical and modal coordinates. The second method is based on wave propagation in buildings and reverse nonlinear structural analysis. The building floors are first scanned with limited number of sensors and the impulse response function (IRF) for each story is identified by deconvolution. Once the IRFs are determined, the story responses are obtained via convolution of the reference signal and the story IRFs at any given instance; and finally, the interstory drifts are approximated. The internal forces and deformations of the structural members are computed by the reverse inelastic structural analysis utilizing nonlinear fiber models, kinematic, and joint equilibrium. The extent and limits of convolution operation as for inelastic structural response is investigated. The change in the shear wave velocity of the damaged are also evaluated.
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    Evaluation of a simple method for the preliminary design of low-to-medium rise reinforced concrete structures
    (Thesis (M.S.) - Bogazici University. Institute for Graduate Studies in Science and Engineering, 2015., 2015.) Akalp, Selahattin.; Luş, Hilmi.; Orakçal, Kutay.
    A simple method is evaluated in this study for suitability to the preliminary design of low-to-medium rise reinforced concrete building-type structures without significant irregularity problems. The method discussed herein, originally proposed by Ersoy (2013) is based on essential rules and guidelines of earthquake engineering such as member ductility and global ductility. Two main classes of structures are considered: buildings consisting solely of frames and buildings with frames and shear walls (also referred to as dual systems). In frame systems, the seismic loads are resisted entirely by columns, whereas in dual systems it is assumed that the columns take 30% and the shear walls take 100% of the lateral loads. It is also assumed that the locations of the shear walls are well configured on the plan so that the lateral loads are distributed fairly throughout the entire frame and the concentration of forces around a specific region is prevented. In an effort to ensure flexural failure of the members, the dimensions of the vertical members are determined under the action of gravity loads and seismic loads. Simple expressions representing the demand are derived as a function of plan area of the stories, column tributary areas, dead loads and live loads. Once the demands and required capacities are specified, dimensions of the load bearing members are determined by taking into account restrictions regarding certain effects leading to brittle failure such as axial stress, shear stress and interstory drifts. For the flexural and shear reinforcements, certain ratios of minimum reinforcements are adopted for the analysis. The buildings are modeled as per ASCE 41-13 with the aforementioned criteria and nonlinear static pushover analyses are performed to validate the expected performance level.