This research proposes a structural retrofit of a reinforced concrete building older than 50 years. The structural system is dual using frames and walls, having an area of 1980 m2 and 4 levels with a total height of 15.50 m. There are three unconventional methods to retrofit this infrastructure. The first is to install steel jackets with bolt anchors. The second methodology is through the use of jackets and anchors of Carbon Fiber Reinforced Polymers (CFRP). The third alternative is through reinforcement of walls with 2 diagonal struts made with CFRP sheets as struts, also installing CFRP anchors at each end of both struts to ensure that these sheets work up to their high levels of tension. These anchors together with the diagonal plates contribute to give ductility to the wall and in turn resist the effects of sliding at the base, a fault that is very common in rigid structures such as walls. Each unconventional reinforcement methodology used in this research is validated using laboratory tests results of reinforced columns and walls retrofitted with every of the three innovative methods. Nonlinear static analysis - Pushover of each alternative was performed and compared with the demand for the 1974 earthquake in Lima, scaling 3 seismic records to a PGA of 0.45g, which is the acceleration of design in Lima. It is shown that these proposals are effective in providing levels of shear base and displacement capacity in the inelastic design. For the 0.40mx0.80m columns, the results show that both reinforcements increase ductility by more than 10%; on the other hand, the proposal of reinforcement in the walls of 40cm thick, produced even better results increasing ductility by 100% and shear base by 100%.

The usefulness of supplementary energy dissipation devices is now quite well-known in the earthquake structural engineering community for reducing the earthquake-induced response of structural systems. However, systematic design procedures for optimal sizing and placement of these protective systems in structural systems are needed and are not yet available. The main objective of this study is, therefore, to formulate a general framework for the optimal design of passive energy dissipation systems for seismic structural applications. The following four types passive energy dissipation systems have been examined in the study: (1) viscous fluid dampers, (2) viscoelastic dampers, (3) yielding metallic dampers and, (4) friction dampers. For each type of energy dissipation system, the study presents the (a) formulation of the optimal design problem, (b) consideration of several meaningful performance indices, (c) analytical and numerical procedures for seismic response and performance indices calculations, (d) procedures for obtaining the optimal design by an appropriate optimization scheme and, (e) numerical results demonstrating the effectiveness of the procedures and the optimization-based design approach. For building structures incorporating linear damping devices, such as fluid and solid viscoelastic dampers, the seismic response and performance evaluations are done by a random vibration approach for a stochastic characterization of the earthquake induced ground motion. Both the gradient projection technique and genetic algorithm approach can be conveniently employed to determine the required amount of damping material and its optimal distribution within a building structure to achieve a desired performance criterion. An approach to evaluate the sensitivity of the optimum solution and the performance function with respect to the problem parameters is also described. Several sets of numerical results for different structural configurations and for different performance indices are presented to demonstrate the effectiveness and applicability of the approach. For buildings installed with nonlinear hysteretic devices, such as yielding metallic elements or friction dampers, the computation of the seismic structural response and performance must be performed by time history analysis. For such energy dissipation devices, the genetic algorithm is more convenient to solve the optimal design problem. It avoids the convergence to a local optimal solution. To formulate the optimization problem within the framework of the genetic algorithm, the study presents the discretization procedures for various parameters of these nonlinear energy dissipation devices. To include the uncertainty about the seismic input motion in the search for optimal design, an ensemble of artificially generated earthquake excitations are considered. The similarities of the optimal design procedure with yielding metallic devices and friction devices are clearly established. Numerical results are presented to illustrate the applicability of the proposed optimization-based approach for different forms of performance indices and types of building structures. / Ph. D.

No description available.

No description available.

The task of &lsquo / earthquake resistant design&rsquo / of buildings is generally considered as the province of engineering profession. Although there exists considerable number of publications related to seismic design (documentations, articles, theses, books, and earthquake codes), most of them are addressed to structural engineers rather than architects. However, earthquake affects whole building and all professionals involved in construction process should have their own roles and responsibilities for earthquake resistance. This thesis is about the roles and responsibilities of architects for being one of the professionals related to building construction and, particularly, the designers of them. Exposure of the level of awareness of architects related to the importance of their architectural designs having significant effects on seismic performance of buildings, and the level of general knowledge of them related to architecture-based seismic design issues is aimed. In this thesis, firstly, terminology related to &lsquo / earthquake&rsquo / phenomena is concisely introduced. Then, the present state of attitudes (interest, awareness and consciousness) of architectural community, architects working in the architectural offices of Ankara, towards earthquake and architecture-based seismic design issues is questioned and evaluated with a survey in the form of questionnaires. The evaluation of the results is presented with the help of statistical software called SPSS. Finally, the architecture-based issues in seismic design are re-explored and introduced for the use of architects. Thus, general idea or basic knowledge is formed, which is inferred from the survey as being one of the ways to enhance the incorporation of architecture-based seismic design issues into architectural design process.

The research described here is part of a multi-university project on “Performance-based Design of New Masonry Structures.” Within the context of that project, the main objectives of this research was to study the inelastic seismic performance of low-rise concrete masonry structures with clay masonry veneer and veneer connectors; to develop analytical models for those structures and the elements comprising them; and to use the results of the research to propose refinements to current design provisions for concrete masonry with clay masonry veneer. The experimental work described here includes the design and testing of concrete masonry wall specimens with clay masonry veneer under quasi-static loading. Identical specimens were subjected to shake-table testing at another university. The experimental work described here also includes the design of a full-scale, one-story concrete masonry building specimen with clay masonry veneer. That building specimen was subjected to shake-table testing at another university. The analytical work of this research includes the development of nonlinear hysteretic models for concrete masonry walls, clay masonry veneer and veneer connectors. The analytical models for wall specimens were calibrated using the results of the quasi-static and shake-table tests of wall specimens. The analytical model for the building specimen was compared with and refined using shake-table test results for the building specimen. Finally, the calibrated and refined analytical model of the building specimen was used for parameter studies intended to supply general information about the behavior of low-rise reinforced concrete masonry structures with clay masonry veneer. Based on the these experimental and analytical results, basic concepts of the seismic response and design of low-rise concrete masonry buildings were reaffirmed; most design and construction requirements of the 2008 MSJC Code and Specification were reaffirmed; and several recommendations were made to improve those requirements. / text

This study investigates seismic response of the Moment-Resisting-Steel Frames (MRSF) with the architectural setbacks. The main objective of the study is to understand the variation of the elastic and inelastic, static and dynamic behavior with changes in the geometric dimensions of the tower portion. A second objective of the study is to determine the adequacy of the analysis procedures of various rigors, specified in current seismic design provision, in predicting those behaviors for MRSF with various size of setback. The analytical study is conducted using a regular and 16 irregular models to capture all possible combinations of configuration of setback in five-story, five-bay MRSFs. An irregular model is developed by gradually changing the horizontal and vertical dimensions of the tower portion of the regular base 2D frame-model. All models were designed for (a) equal global displacement and uniform distribution of inter-story drift under First-Mode (FM) lateral force distribution pattern at first significant yield, and (b) equal period of vibration at the first mode, using Nonlinear Static Seismic analysis procedure. Among the conclusions derived from the research is that the variation of (a) the elastic and inelastic inter-story drift, the ductility demand for the top three stories, and (b) the elastic and inelastic global displacement exhibited a pattern similar to the variation of the FM participation factor at the roof, PF1Φr,1. The square-root-of-sum-of-square (SRSS) distribution provided accurate estimates of elastic story shear and inter-story drift demand as well as the story yield strength and drift.

The aim of this thesis is to demonstrate that it is possible to design earthquake resistant residential structures without significant compromises in the spatial quality and economic viability of the building. The specific type of structural system that this thesis focuses on is the reinforced concrete skeleton system. The parametric examples and key studies that are used in this research are chosen among applied projects in the city of Bolu. This city is chosen due to its location on the North Anatolian Fault and its destructive seismic history. The structural validity of the hypothesis was demonstrated through an analytical process during which a set of 7 models were tested. 5 of these were designed as idealized parametric models and 2 of them were based on actual buildings destroyed in earthquakes. The architectural validity of the hypothesis was demonstrated on a set of 3 architectural projects. Projects were subjected to a comparative evaluation between their original states and the modified seismically resistant versions. The architectural comparison between earthquake resistant and non-resistant states was made on a planimetric basis. Comparison parameters were: floor area / size, location and number of rooms / and access to view. The feasibility of seismically resistant reinforced concrete residential buildings was demonstrated through an approximate cost analysis which has proven that designing earthquake resistant structures only resulted in an acceptable 4-8 percent rise in the overall building cost.

The research described here is part of a multi-university project on “Performance-based Seismic Design Methods and Tools for Reinforced Masonry Shear-Wall Structures.” Within the context of that project, the objective of the research described in this dissertation was to develop and validate a specific displacement-based seismic design methodology for masonry structures. Experimental work consisted of reversed cyclic loading tests of reinforced masonry wall segments with different boundary conditions, aspect ratios, axial loads, and reinforcement detailing. Analytical work consisted of developing analytical models for in-plane concrete masonry shear wall segments; calibrating those models using reversed cyclic test data; and using those models to successfully predict the nonlinear seismic response of two full-scale, multi-story reinforced masonry specimens tested on the shake-table at the University of California at San Diego. Design work consisted of the force-based and displacement based design of those specimens. Based on the results, provisions for displacement-based seismic design are proposed for inclusion in United States design codes. / text

Η παρούσα διδακτορική διατριβή πραγματεύεται τις παραμένουσες μετακινήσεις κατασκευών υπό σεισμικές δράσεις, με στόχο την πληρέστερη κατανόηση και ποσοτικοποίησή τους. Για τον υπολογισμό των παραμενουσών μετακινήσεων πραγματοποιήθηκαν μη-γραμμικές δυναμικές αναλύσεις μονοβάθμιων συστημάτων, δίνοντας ιδιαίτερη έμφαση στη μορφή του νόμου υστέρησης, ώστε να έχει τα χαρακτηριστικά που προσιδιάζουν σε κατασκευές οπλισμένου σκυροδέματος. Συγκεκριμένα, υιοθετήθηκε η κατηγοριοποίηση των κατασκευών ΟΣ κατά Erberik (2011) σε τρεις βασικές Κατηγορίες, ανάλογα με την υστερητική τους συμπεριφορά: (α) νέα κτίρια, σχεδιασμένα με σύγχρονους αντισεισμικούς κανονισμούς, (β) κτίρια που δεν καλύπτουν πλήρως τους σύγχρονους αντισεισμικούς κανονισμούς και (γ) παλαιά κτίρια που δεν διαθέτουν σεισμική αντοχή. Για λόγους σύγκρισης εξετάστηκε και η ιδανική υστερητική συμπεριφορά. Η παραμένουσα μετακίνηση κάθε συστήματος, Ures, κανονικοποιήθηκε ως προς τη μέγιστη μετακίνηση που θα είχε λάβει το σύστημα αν η απόκρισή του ήταν ελαστική, με 5% απόσβεση, Sd, αλλά και ως προς τη μέγιστη ανελαστική μετακίνηση του συστήματος, Umax. Οι λόγοι Ures/Sd και Ures/Umax μελετήθηκαν εκτενώς και αναπτύχθηκαν πιθανοτικά προσομοιώματα για τα φάσματα ανηγμένων παραμενουσών μετακινήσεων που προέκυψαν. Επιπλέον, διαπιστώθηκε η επίδραση της ύπαρξης παλμού στην εδαφική κίνηση στους λόγους Ures/Sd και Ures/Umax, και διερευνήθηκαν οι λόγοι της επιρροής του. Περαιτέρω, οι πειραματικές παραμένουσες μετακινήσεις πέντε τριώροφων επίπεδων πλαισίων ΟΣ που υποβλήθησαν σε ψευδοδυναμικές δοκιμές με εξωτερικά επιβαλλόμενα κατακόρυφα φορτία στο METU (Middle East Technical University) συσχετίστηκαν με τις αναλυτικές από μη-γραμμικές δυναμικές αναλύσεις χρονοϊστορίας. Εξετάστηκε αν τα διαθέσιμα υπολογιστικά εργαλεία ανάλυσης δύνανται να υπολογίσουν ικανοποιητικά τις παραμένουσες μετακινήσεις, αλλά και ποιοι παράγοντες ευθύνονται για τις ασυμφωνίες μεταξύ πειραματικών και αναλυτικών τιμών. Τέλος, οι λόγοι Ures/Sd και Ures/Umax που προέκυψαν από την ανάλυση των δοκιμίων και από την επεξεργασία των πειραματικών αποτελεσμάτων συγκρίθηκαν με τα φάσματα ανηγμένων παραμενουσών μετακινήσεων μονοβάθμιων συστημάτων. / The present study aims to evaluate and quantify seismic residual displacements. In order to compute residual displacements, non-linear dynamic analyses were conducted for single degree of freedom systems with cyclic force-deformation relations typical of reinforced concrete structures. To this end, the versatile modeling approach of Erberik (2011) was adopted, which was tuned to three different categories of RC structures, ranging from new earthquake resistant ones to existing substandard construction, with an intermediate situation. The ideal hysteretic behavior was also examined. For each single degree of freedom system, residual displacement, Ures, was expressed as ratio to the peak inelastic, Umax or the 5%-damped elastic displacement of the response, Sd. Ratios Ures/Sd and Ures/Umax were thoroughly studied and normalized residual displacements response spectrums were created. Moreover, it was noted that the existence of a distinct velocity pulse in the ground motion affects the magnitude of these ratios, and the reasons of this influence were further investigated. Furthermore, experimental residual displacements from five three-story reinforced concrete frames, which were subjected to pseudo-dynamic tests in METU (Middle East Technical University), were compared to analytical residual displacements from non-linear time-history analyses. The study focused on whether modern analysis tools can accurately predict residual displacements and which factors create the observed discrepancies between analytical and experimental values. Lastly, ratios Ures/Sd and Ures/Umax from experiments and time-history analyses were compared to the normalized residual response spectrums of single degree of freedom systems.