Thesis (M.Eng. Sc.) -- University of Adelaide, 1983. / Bibliography: leaves 91-94

Thesis (Ph. D. in Geophysics)--University of California, Berkeley, June 1977. / "January 1977." Includes bibliographical references.

Drawing from trends in environmental and disaster studies, this study examines the meaning of earthquakes within the official histories of China's Tang Dynasty (618-907), specifically those during the reign of Emperor Dezong (r. 785-805), as both historiographic metaphors and incidents of real natural-induced disaster. Earthquakes, like other forms of potentially harmful natural phenomena, demonstrated, the Chinese believed, Heaven's dissatisfaction with a sitting ruler. Over time, ministers and court scholars sought to draw connections between earthquakes and specific forms of behavior in attempts to perhaps prevent future incidents of seismic reproach. And though certain relationships are articulated more clearly in some parts of the histories than others, earthquakes nevertheless demonstrated an ability to engender a great sense of uncertainty and discord within historical memory. Consequently, the reading of the natural world codified in the official histories marked an attempt by the Chinese state to control human behavior for generations to come.

No description available.

No description available.

Inelastic behavior is inevitable in most structures subjected to strong earthquake forces. Any rational design procedure, therefore, should attempt to estimate the amount of inelastic behavior to be expected in each member of the structure. Methods of dynamic response analysis based on linear elastic assumptions can be carried out conveniently and economically. Such methods, however, can not provide any direct information on the inelastic behavior of the structure. On the other hand, time-step analysis programs can 'truly' simulate the non-linear behavior of the structure but are seldom used because of their cost and complexity. There is, therefore, a need for practical and efficient methods which can account for the inelastic behavior. Some methods for estimating the inelastic response and damage patterns of structures under ground motions are presented. One is the Modified Substitute Structure Method which is now revised so that the structure can be analysed for gravity loads prior to the seismic analysis. The other method which is proposed here uses a static analysis. The structure is first analysed for gravity loads and then lateral seismic forces (as given by the appropriate codes) are applied. The amplitude of the lateral forces is gradually increased, maintaining the specified pattern; a plastic hinge is placed where a member has yielded and the structure stiffness matrix revised each time. This process is continued until the structure has reached a predetermined displacement. At this point, the rotation of the plastic hinges is known and then the member curvature ductilities can be calculated. Thus, an idea is obtained, of the damage pattern in the structure. A computer program has also been written for analysing the structures by 'Freeman's Method' to predict the inelastic response of structures under severe ground motion. The method gives the overall inelastic response without predicting the pattern of local damage. These various methods are then compared by analyzing two idealized structures. A third, real structure, an office/residential building in downtown Vancouver is also analysed by these methods and the results compared with those obtained by a time-step analysis program DRAIN-2D. These methods appear to give good results and it is hoped that they will be found useful by practising engineers. A user's guide and the listing of these programs are included in the appendices. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

A computational procedure for the evaluation of inelastic responses and ductility demands of three dimensional buildings subjected to multi-component earthquake excitations is presented. The modified substitute structure method is based on elastic modal analysis but is an iterative procedure which involves a fictitious linear structure whose stiffness and damping characteristics are related to the ductility demands. The building is idealized as an assembly of plane frames interconnected by rigid diaphragms. Coupling of individual frames through common columns is taken into account. It is not necessary for all storey masses to lie on a vertical line, so that structures with varying floor dimensions can be modelled. Two reinforced concrete structures of different types, moment resisting frames and coupled wall cores, are tested with the method. The accuracy of the method for predicting ductility demands and lateral deflections is determined by comparison with averaged results obtained from the time step analysis program DRAIN-TABS. The proposed method fills the void between elastic modal analysis which cannot provide information on inelastic behaviour of the structure, and full scale time step analysis which is complex and expensive to use. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

This thesis is concerned with the response of multi-story prestressed concrete frames to seismic loading, and the ductility demands of the constituent members. In that regard, an idealized model for the end moment-plastic rotation relationship of prestressed concrete members was developed based on a published moment-curvature idealization for prestressed concrete. The idealized moment-rotation model, which included stiffness and strength degradation, was used to introduce all post-elastic action In a beam-column element, which consisted of an elastic beam connecting concentrated hinges modeled as nonlinear rotational springs. The subsequent use of the element in the nonlinear analysis of a typical multi-story prestressed concrete frame indicated that both the lateral displacements, and the girder end rotational and hinge curvature ductilities would be somewhat higher for a prestressed concrete frame than for a reinforced concrete frame with the same initial stiffness and strength. As an effort to limit deflections, and minimize member damage under moderate seismic loading the use of a higher base shear for a prestressed concrete structure than for a comparable reinforced concrete structure appears warranted. / Applied Science, Faculty of / Civil Engineering, Department of / Unknown

No description available.

Thesis (MScIng)--Stellenbosch University, 2005. / Some digitised pages may appear illegible due to the condition of the original hard copy. / ENGLISH ABSTRACT: Reinforced concrete (RC) frames with unreinforced masonry infill form the structural system of many buildings and this is also true for South Africa. It is common practice to consider the masonry infill as a non-structural component and therefore it does not contribute to the performance of the Re frame buildings under lateral loading such as earthquake loading. This is done by leaving a sufficient gap between the Re frame and the infill. This ensures that there is no contact between the frame and the infill during an earthquake event. However, it has been suggested that masonry infill can play a significant role in the performance of a Re frame building under lateral loading. The first part of the study focuses on the South African situation. The relevance of shear walls in these Re frame buildings as well as the size of the gap (between frame and infill) left in practice, are investigated. This is done by finite element analysis. The second part of the study focuses on the effects that the infill can have on the global performance of the structure when there is full contact between the Re frames and infill. The effect of openings in the infill to the response of the frame is also investigated. Finite element models of single span Re frames with infill is built and analyzed in order to investigate possible damage to the infill, frame infill interaction and to obtain the non linear stiffness of the frame with infill as a whole. This obtained non linear stiffness can be modelled in Diana as a non linear spring that will be used in the development of a simplified analysis method. The simplified method developed consists of a frame and two such non linear springs, placed diagonally, and which have the same force versus displacement behaviour as the original frame with infill. These single span frames can be added together to model a whole frame. In a first step to generalise the simplified method, various geometries of infills are considered, varying span and height, as well as opening percentage, representing windows and doors of varying total area and positioning. However, in this study a single masonry type, namely solid baked clay bricks set in a general mortar, is considered. To generalise the approach further, other masonry types can be considered in the same way. The use of these springs in a simplified model saves computational time and this means that larger structures can be modelled in Diana to investigate response of'Rf' frame buildings with infill. The work reported in this thesis considers only in-plane action. Out-of-plane-action of the masonry infill has been reported in the literature to be considerable, under the condition that it is sufficiently tied to the frame to prevent mere toppling over, causing life risking hazards in earthquake events. This matter should be studied in continuation of the current research to generalise the simple approach to three dimensions. / AFRIKAANSE OPSOMMING: Gewapende betonrame (GBR-e) met ongewapende messelwerk invulpanele (invul) vorm die strukturele ruggraat van vele geboue en dit geld ook vir geboue in Suid-Afrika. Dit is algemene praktyk om die invulpaneel in sulke geboue as 'n nie-strukturele komponent te beskou. Daarvolgens dra dit nie by tot die gedrag van 'n GBR gebou onderhewig aan 'n aarbewing nie. Dit word bereik deur 'n groot genoeg gaping tussen die betonraam en die invul te los. Die gevolg is dat daar geen kontak tussen die betonraam en die invul plaasvind indien daar 'n aardbewing sou voorkom nie. Dit is egter voorgestel dat invul 'n noemenswaardige rol kan speel in die gedrag van 'n GBR gebou onderwerp aan 'n horisontale las. Die eerste deel van die studie fokus op die Suid-Afrikaanse situasie. Die relavansie van skuifmure in GBR geboue asook die grootte van die gaping (tussen die raam en invul) wat in die praktyk gebruik word, word ondersoek. Dit word gedoen met behulp van eindige element analises. Die tweede deel van die studie fokus op die effek wat invul kan hê op die globale gedrag van 'n struktuur wanneer daar volle kontak tussen die GBR en die invul is. Die effek wat die teenwoordigheid van openinge in die invul kan hê op die gedrag van 'n GBR is ook ondersoek. Eindige element modelle van enkelspan GBR met invul is gemodelleer en geanaliseer om die moontlike skade aan die invul, die interaksie tussen die GBR en die invul asook die nie-lineêre styfheid van die raam en invul as 'n geheel, te ondersoek. Hierdie nielineêre styfheid kan in Diana as 'n nie-lineêre veer gemodelleer word en word gebruik in die ontwikkeling van 'n vereenvoudigde metode. Hierdie vereenvoudigde metode wat ontwikkel is, bestaan uit 'n raam en twee sulke nielineêre vere (diagonaal geplaas). Die raam met vere het dieselfde krag teenoor verplasingsgedrag as die van die oorspronklike raam met invul wat dit voorstel. Hierdie rame kan saamgevoeg word om 'n raam uit 'n gebou as 'n geheel te modelleer. Verskeie invul geometrieë word gebruik in die analises in 'n eerste stap om die vereenvoudigde metode te veralgemeen. Die span en hoogte asook opening persentasie van die invul word gevariëer om vensters en deure van veskeie grootte en posisie voor te stel. In die studie, 'n enkel messelwerk tipe, naamlik solied klei bakstene geset in algemene mortar, word gebruik. Ander messelwerk tipes kan gebruik word om die metode verder te veralgemeen. Die gebruik van die vere in die vereenvoudigde metode spaar berekenings tyd en dit beteken dat groter strukture in Diana gemodelleer kan word om die gedrag van GBR geboue met invul te ondersoek. Die werk gedoen in die tesis neem slegs in-vlak aksie in ag. Literatuurstudie dui daarop dat goeie uit-vlak-aksie van messelwerk invul bestaan, mits dit goed geanker is aan die raam om te verseker dat dit nie kan omval en 'n gevaar vir lewens in 'n aardbewing inhou nie. Dit behoort verder bestudeer te vord in die vervolging van die huidige ondersoek om die vereenvoudige metode na drie dimensies te veralgemeen.