Rubber material used in seismic isolation systems has a tendency to stiffen in cold climate conditions. Structural responses of rubber based seismic isolation bearings are known to be temperature dependent. The main focus of this research is to investigate the temperature related behavior shifts at a certain type of a rubber based seismic isolation system. This research is a complementary study to a recent experimental study on a newly developed seismic isolator called &ldquo / Ball Rubber Bearing&rdquo / (BRB). BRBs can be easily manufactured as in the case of a standard rubber based bridge bearing and can provide adequate energy dissipation during an earthquake. However, structural response of BRBs at low temperatures has not been examined yet. In this research, behavior of BRBs exposed to different temperatures is examined under combined axial and cyclic lateral load. The performance of the specimens used in this study, &ldquo / Elastomeric Bearing&rdquo / (EB) and &ldquo / Ball Rubber Bearing&rdquo / (BRB) are compared with each other and also with previous researches conducted in this topic. The results indicated that BRBs show better performance at low temperatures in terms of energy dissipation compared to room temperature performance. Big size bearings have higher energy dissipation per cycle compared to small size bearings by reason of size effect. The higher damping percentage is observed at the small size bearings compared to big size bearings due to better confinement of the inner core. As a result of temperature records heat exchange is not detected in the rubber during cyclic loading.

Historic structures form a very important part of our cultural heritage and should be well protected. Therefore, full comprehension of the structural behavior of historic structures is of prior importance. A seriously damaged single domed mosque of 16th century Classical Ottoman Architecture was investigated in this study. Serious damages have been observed at various structural elements including the dome and the structural masonry walls, recently leading the structure&#039 / s closure to service. The main objective of this study is to find out the possible reasons of the damage. The Mosque was constructed on silty-clay soil and the water table has been changed considerably due to the drought in recent years causing soil displacements. The structure is modeled with linear finite element approach. The masonry walls are modeled with homogenized macro shell elements. The change in water table is imposed on the Mosque as displacement at foundation joints. The results of the analyses have been compared with the observed damage and the finite element model has been calibrated according to the observed damage. Some rehabilitation methods have also been proposed. Mini pile application up to firm soil (rock) was recommended to prevent the soil displacement. A steel ring around the damaged dome base was proposed to avoid any further propagation of cracks. Furthermore, the cracks on the masonry walls should also be repaired with a suitable material that is also compatible with the historic texture.

The solution of the linear system of equations is one of the core aspects of Finite Element Analysis (FEA) software. Since large amount of arithmetic operations are required for the solution of the system obtained by FEA, the influence of the solution of linear equations on the performance of the software is very significant. In recent years, the increasing demand for performance in the game industry caused significant improvements on the performances of Graphical Processing Units (GPU). With their massive floating point operations capability, they became attractive sources of performance for the general purpose programmers. Because of this reason, GPUs are chosen as the target hardware to develop an efficient parallel direct solver for the solution of the linear equations obtained from FEA.

A two-phase study was undertaken to investigate the fundamental period of concentrically braced steel frames (CBFs) designed according to Eurocode 8. In the first phase, typical office buildings were studied by conducting two types of designs which are called as iterative and non-iterative. Non-iterative design is composed of obtaining final period by designing the structure with lower bound expression in Eurocode 8 while iterative design is similar to the non-iterative one but an updating of periods was considered in order to converge assumed and final periods. Different overstrength provisions are considered in the study. Lower bound expression in Eurocode 8 results in shorter periods which indicates that this expression can be safely utilized. The lower bound represented by Tremblay (2005) is also admissible except for some cases including shorter periods. In the second phase, a simple expression is derived for estimating the design base acceleration for braced frames proportioned according to Eurocode 8. This method requires inelastic top story drift values which were obtained from structures designed in the first phase using iterative method. These drifts were represented by simple expressions utilizing data fitting techniques. The method gives suitable first order estimate for the design base acceleration.

Nonlinear response history analysis is considered as the most accurate analytical tool for estimating seismic response. However, there are several shortcomings in the application of nonlinear response history analysis, resulting from its complexity. Accordingly, simpler approximate nonlinear analysis procedures are preferred in practice. These procedures are called nonlinear static analysis or pushover analysis in general. The recently developed Generalized Pushover Analysis (GPA) is one of them. In this thesis study, GPA is presented and evaluated comparatively with the nonlinear time history analysis and modal pushover analysis. A generalized pushover analysis procedure was developed for estimating the inelastic seismic response of structures under earthquake ground excitations (Sucuoglu and G&uuml / nay, 2011). In this procedure, different load vectors are applied separately to the structure in the incremental form until the predefined seismic demand is obtained for each force vector. These force vectors are named as generalized force vectors. A generalized force vector is a combination of modal forces, and simulates the instantaneous force distribution on the system when a given response parameter reaches its maximum value during the dynamic response. In this method, the maximum interstory drift parameters are selected as target demand parameters and used for the derivation of generalized force vectors. The maximum value of any other response parameter is then obtained from the analysis results of each generalized force vector. In this way, this procedure does do not suffer from the statistical combination of inelastic modal responses. It is further shown in this study that the results obtained by using the mean spectrum of a set of ground motions are almost identical to the mean of the results obtained from separate generalized pushover analyses under each ground motion in the set. These results are also very close to the mean results of nonlinear response history analyses. A practical implementation of the proposed generalized pushover analysis is also developed in this thesis study where the number of pushovers is reduced in view of the number of significant modes contributing to seismic response. It has been demonstrated that the reduced generalized pushover analysis is equally successful in estimating maximum member deformations and member forces as the full GPA under a ground excitation, and sufficiently accurate with reference to nonlinear response history analysis.

Nonlinear response history analysis is regarded as the most accurate analysis procedure for estimating seismic response. Approximate analysis procedures are also available for the determination of seismic response and they are preferred over nonlinear response history analysis since much less computational effort is required and good response prediction is achieved by employing rather simple concepts. A generalized pushover analysis procedure is developed in this thesis study as an approximate analysis tool for estimating the inelastic seismic response of structures under earthquake ground excitations. The procedure consists of applying generalized force vectors to the structure in an incremental form until a prescribed target interstory drift demand is achieved. Corresponding generalized force vectors are derived according to this target drift parameter and include the contribution of all modes. Unlike many approximate analysis procedures, response of the structure is directly obtained from generalized pushover analysis results without employing a modal combination rule, eliminating the errors cultivating from these methods. Compared to nonlinear response history analysis, generalized pushover analysis is less demanding in computational effort and its implementation is simpler relative to other approximate analysis procedures. It is observed that the proposed analysis procedure yields results accurately in comparison to the other nonlinear pushover analysis methods. Accordingly it can be suggested as a convenient and sound analysis tool.

Οι αιμοσφαιρινοπάθειες, συμπεριλαμβανομένης της β-θαλασσαιμίας και της δρεπανοκυτταρικής αναιμίας, συγκαταλέγονται ανάμεσα στις πιο κοινές μονογονιδιακές αναταραχές παγκοσμίως, που χρήζουν αποτελεσματικής θεραπευτικής στρατηγικής. Σήμερα, η επανενεργοποίηση των γονιδίων της γ-σφαιρίνης φαίνεται να είναι μια ενδιαφέρουσα θεραπευτική προσέγγιση για τους ασθενείς που πάσχουν από β-τύπου αιμοσφαρινοπάθειες. / Hemoglobinopathies are amongst the most common single gene disorders worldwide, including beta-thalassemia and sicle cell disease (SCD), seeking for therapeutic intervention. The reactivation of the human gamma-globin genes is considered to be a therapeutic strategy for beta-type hemoglobinopathies patients.

The purpose of this study is to model and analyze the nonplanar shear wall assemblies of shear wall-frame structures. Two three dimensional models, for open and closed section shear wall assemblies, are developed. These models are based on conventional wide column analogy, in which a planar shear wall is replaced by an idealized frame structure consisting of a column and rigid beams located at floor levels. The rigid diaphragm floor assumption, which is widely used in the analysis of multistorey building structures, is also taken into consideration. The connections of the rigid beams are released against torsion in the model proposed for open section shear walls. For modelling closed section shear walls, in addition to this the torsional stiffness of the wide columns are adjusted by using a series of equations. Several shear wall-frame systems having different shapes of nonplanar shear wall assemblies are analyzed by static lateral load, response spectrum and time history methods where the proposed methods are used. The results of these analyses are compared with the results obtained by using common shear wall modelling techniques.

This thesis focuses on the investigation of behavior of thick and moderately thick laminates under transverse and horizontal loading for different boundary conditions and configurations. An efficient finite element solution is proposed for analyzing composite laminates. Based on a combination of composite theory and 3-D Elasticity Theory, a 3-D finite element program is developed in MATLAB for calculating the stresses, strains and deformations of composite laminates under transverse and/or horizontal loading for different boundary conditions. The applicability of the formulation to analysis of laminated rubber bearings is also examined in this study. Since it is very important to calculate the correct stress state when developing models for composite behavior, the 3-D Elasticity Theory is used in this research. Numerical results are presented for various problems with different lamination schemes, loading and boundary conditions. In order to verify the analysis and the numerical calculations, numerical solutions obtained in this study are compared with available closed form solutions in the literature, experiment results and a commercial finite element program, namely ANSYS. The results obtained using the present finite element is found to be in acceptable and good agreement with the closed form solutions in the literature for thick and moderately thick rectangular and square plates.

The recent earthquakes in Turkey have shown the poor seismic performance of reinforced concrete. This led to widespread utilization of several strengthening methods, each of which is convenient in different aspects. However, what is required to apply any of these methods is to evacuate the building in question since the interruptions are mostly within the building and to the structural members. This study proposes a method for external strengthening of typical five storey reinforced concrete buildings that represent the majority of the built environment in Turkey. The method suggests addition of shear walls, which are connected to each other by means of diaphragms on two floor levels, to the existing external columns at four corners of the building. The positive effect of shear walls in seismic performance is already known / however / basically, the aim of this study is to discuss the feasibility of the proposed method in terms of architectural viewpoint since the method unavoidably covers great modifications on the architectural form of the building. Hence, the research mostly explores whether it is possible to give the reinforced concrete residential buildings, which constitute the majority of the built environment especially after 1950s due to the unhealthy urbanization period in Turkey, a common characteristic appearance by means of external structural members. As a whole, proposing an external strengthening method that provides not to evacuate the space, the study searches to obtain a typical fa&ccedil / ade resemblance by means of additional structural members.