Seismic design procedures were first incorporated in building design codes in the 1920s and 1930s when inertial loadings began to be appreciated. In the absence of reliable ground measurements during an earthquake as well as detailed knowledge of the dynamical response of structures, the seismic action was taken into account for design purposes as a statical horizontal force corresponding to about 10% of the weight of the structure.
By the 1960s ground measurements during an earthquake in the form of accelerograms were becoming more generally available. At the same time the development of strength design philosophies and of computer-based analytical procedures such as the spectral-modal analysis and the time-history analysis, facilitated the examination of the dynamical response of multi-degree-of-freedom structures (MDOF). According to these procedures, the calculations were carried out in a deterministic fashion. The response of the structure was assumed to be in the elastic range and the earthquake loading was taken into account considering the typical seismic intensity and soil nature of the site of the structure.
As the records of strong ground motion were increasing, it became apparent that the code provisions were inadequate in providing the required structural strength of the building to withstand an intense earthquake. This was recognized analysing the damage in structures that had been close to resonance. In fact the vibrating masses of structures in such a situation had often been exposed to accelerations from two to six times the maximum base acceleration that, of course, would induce forces on the structural elements much larger than expected in the design phase. However the lack of strength did not always result in failure and sometimes not even severe damage. On the other hand in specified regions of the structure (especially the ones with shear dominated behaviour) a rapid reduction in strength (brittle failure) was observed leading to local failure that often resulted in the formation of mechanisms and consequently collapse of the structure.
This type of observations called the attention of structural engineers to the property of the materials or of the structures to offer resistance in the inelastic domain of response. This property is generally known as ductility and includes the ability to sustain deformations in the inelastic range without significant loss of strength and a capacity to absorb energy by hysteretic behaviour
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I was browsing here as usual today only when I realised I have not seen some of my old friends here for long time. And I certainly not mean to coax for a new post/thread from them. They are some of my most respected users since I started here and I am wondering how are things going on their end? And yes, I checked their profile, some have been inactive for long but some was here just now!
In no particular hierarchy.
Robertsas: My fellow running moderator. Indonesian experienced engineer.
Ultra Zone
juice: A pioneer moderator
abudabeeja: A top book contributor prior to bookoz and libgen days. Quiet after a short moderating stint.
timosi: I don't know him well enough but once a great contributor as well.
Kamran: Pioneer and Mohsen's countrymate.
kowheng: Early days of experience sharing in his field, follow by a great period of moderating. The most consistent and ever present moderator I have seen in here.
struceng: One of the greatest users around. Very knowledgeable and helpful.
Flexi: One of the oldest VIP.
This is a friend and a fellow user saying Hello. By no means this thread mean to pressure you guys but please drop a line in this thread (of course you can PM me as well if you wish) when you are free to.
Till then, have a great day(or evening on your side) ahead!
PERFORMANCE-BASED APPROACH IN SEISMIC DESIGN OF EMBEDDED RETAINING WALLS
Author: CIRO VISONE | Size: 4.1 MB | Format:PDF | Quality:Unspecified | Publisher: UNIVERSITÀ DEGLI STUDI DI NAPOLI FEDERICO II | Year: 2008 | pages: 203
The increasing use of the underground spaces and the last seismic events in the urban areas have driven many researchers of different countries to deepen the knowledge on the dynamic behaviour of the structure embedded in the subsoil. This thesis attempts to give some contributes on the application of the performance based approach for the seismic design of the embedded retaining walls. After an overview on the earth pressure theories proposed by different authors, the static and seismic design methods commonly adopted in the current practice and
based on pseudostatic approaches are recalled. Several limitations on these procedures can be recognized: the difficulties on the
definition of the seismic coefficient; the calculation of the expected earthquakeinduced displacements around the construction. Moreover, in the framework of the Performance-Based Design, these methods do not able to describe the response of the retaining systems to a given earthquake. The seismic displacements of the flexible walls are evaluated by means of Newmark sliding block procedures, that were developed for rigid structures, and the yield sequence of the different structural
components can not be predicted. Then, the application of the hierarchical resistance criteria in the dimensioning of the various parts can not be applied. In this thesis, different level of analysis are highlighted in relation to the importance of the structure and to the design phase.
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Recent earthquake surveys have revealed the significance of RC walls as an integral part of structures. It reduces the structure damage to some extent. However, like other structural member they too are vulnerable. Researchers on basis of their post eartthquake survey and laboratary experiments have concluded that the RC wall buildings sustained damage, mainly due to design and construction work flaws. In this thesis experimental result of shear walls is discussed. They were designed under-reinforced to fail in shear in ase of short wall and in flexure for slender walls. Three out of these six specimens, in each case, were strengthened externally with CFRP strips bonded to wall panel and mesh anchors installed at wall foundation joint. Two specimens, one RC and one CFRP retrofitted (short and slender wall each), were subjected to static load test and three specimens, one RC and two to three CFRP retrofitted, were subjected to quasi static cyclic load tests. The test result analysis discussion includes failure mode, stiffness, ultimate load capacity, ductility, and energy dissipation
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Strengthening Design of Reinforced Concrete with FRP establishes the art and science of strengthening design of reinforced concrete with fiber-reinforced polymer (FRP) beyond the abstract nature of the design guidelines from Canada (ISIS Canada 2001), Europe (FIB Task Group 9.3 2001), and the United States (ACI 440.2R-08). Evolved from thorough class notes used to teach a graduate course at Kansas State University, this comprehensive textbook:
Addresses material characterization, flexural strengthening of beams and slabs, shear strengthening of beams, and confinement strengthening of columns Discusses the installation and inspection of FRP as externally bonded (EB) or near-surface-mounted (NSM) composite systems for concrete members Contains shear design examples and design examples for each flexural failure mode independently, with comparisons to actual experimental capacity Presents innovative design aids based on ACI 440 code provisions and hand calculations for confinement design interaction diagrams of columns Includes extensive end-of-chapter questions, references for further study, and a solutions manual with qualifying course adoption
Delivering a detailed introduction to FRP strengthening design, Strengthening Design of Reinforced Concrete with FRP offers a depth of coverage ideal for senior-level undergraduate, master’s-level, and doctoral-level graduate civil engineering courses.
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Boundary Element Method for Plate Analysis offers one of the first systematic and detailed treatments of the application of BEM to plate analysis and design.
Aiming to fill in the knowledge gaps left by contributed volumes on the topic and increase the accessibility of the extensive journal literature covering BEM applied to plates, author John T. Katsikadelis draws heavily on his pioneering work in the field to provide a complete introduction to theory and application.
Beginning with a chapter of preliminary mathematical background to make the book a self-contained resource, Katsikadelis moves on to cover the application of BEM to basic thin plate problems and more advanced problems. Each chapter contains several examples described in detail and closes with problems to solve. Presenting the BEM as an efficient computational method for practical plate analysis and design, Boundary Element Method for Plate Analysis is a valuable reference for researchers, students and engineers working with BEM and plate challenges within mechanical, civil, aerospace and marine engineering.
One of the first resources dedicated to boundary element analysis of plates, offering a systematic and accessible introductory to theory and application
Authored by a leading figure in the field whose pioneering work has led to the development of BEM as an efficient computational method for practical plate analysis and design
Includes mathematical background, examples and problems in one self-contained resource
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