Base Isolation retrofit is a costly operation that is most commonly appropriate in high asset value facilities and may require partial or the full removal of building occupants during installation. 9.4 Current Seismic Design Practice for Culverts or Other Buried Structures Currently there is no standard seismic design methodology or guidelines for the design of culvert structures, including Section 12 within the current … Viber. The materials used for Elastomeric Isolators are natural rubber, high-damping rubber, or another elastomer in combination with metal parts. The following factors affect and are affected by the design of the building. Buildings seldom overturn—they fall apart or "pancake". Second, performance-based requirements, which may exceed the minimum life safety requirements of current seismic codes, must be established to respond appropriately to the threats and risks posed by natural hazards on the building's mission and occupants. B.A. It is worth noting at the start that seismic analysis determines a set of forces for which it is expected (statistically) that if those forces are designed for and other design precautions taken (additional seismic design) then in the event of an earthquake the structure may well suffer extensive damage but will not collapse and for some categories of building should actually remain serviceable. See ASCE 7-05 Table 12.12-1 for footnotes. The engineering bedrock is assumed to be the soil layer whose shear wave velocity is > 400 m/s. Moment-Resistant Frames: Column/beam joints in moment-resistant frames are designed to take both shear and bending thereby eliminating the space limitations of solid shear walls or braced frames. Instead, only general guidelines and rec- ommendations on methodology for seismic evaluation under the effects of permanent ground deformation will be provided. Code (IBC), 2010 Minimum Design Loads for Buildings and Other Structures (ASCE 7-10) and 2008 Special Design Provisions for Wind and Seismic (SDPWS) requirements applicable to the seismic design of wood structures. This course introduces seismic design of civil engineering structures. Now the question is how to determine seismic zone for some particular area? Diaphragms: Floors and roofs can be used as rigid horizontal planes, or diaphragms, to transfer lateral forces to vertical resisting elements such as walls or frames. Retrofitting existing buildings is often easier with dampers than with base isolators, especially if the application is external or does not interfere with the occupants. The applicable requirements of NCh433 (NCH, 1996), for the seismic design of conventional structures, were also fulfilled. Many governmental agencies at the federal level have seismic standards, criteria, and program specialists who are involved in major building programs and can give further guidance on special requirements. Tall buildings will undergo several modes of vibration, but for seismic purposes (except for very tall buildings) the fundamental period, or first mode is usually the most significant. The basis of the approach is the construction of a conditional multivariate distribution of a general set of ground motion intensity measures. It explains the basic mechanisms of earthquakes, generation of design basis ground motion, and fundamentals of structural dynamics; further, it delves into geotechnical aspects related to the earthquake design, analysis of multi degree-of-freedom systems, and seismic design of RC structures and steel … An example is Eccentric Bracing whereby the controlled deformation of framing members dissipates energy. The basic design earthquake acceleration response spectra S0 of the seismic ground motion at the exposed outcrop engineering bedrock is given as. Reinforced masonry walls (good energy absorption if walls and floors are well integrated; proportion of spandrels and piers are critical to avoid cracking), Reinforced concrete walls (good energy absorption if walls and floors well integrated; proportion of spandrels and piers are critical to avoid cracking), Steel frame with masonry fill-in walls (good energy absorption if bay sizes are small and building plan is uniform), Steel frame, braced (extensive bracing, detailing, and proportions are important), Steel frame, moment-resisting (good energy absorption, connections are critical), Steel frame, eccentrically braced (excellent energy absorption, connections are critical), Pre-cast concrete frame (poor performer without special energy absorbing connections). This is because, unlike with the design of the sluiceway gate column, seismic-resistant design considering seismic load has not been applied in the case of the sluiceway box culvert. A value of 1.0 is intended for items that would behave in a very brittle fashion before failure. It has been suggested (e.g., Priestley and Kowalsky, 2000) that the initial input into the design process should be the permitted seismic displacement rather than the strength for seismic forces. The structures need to be designed and detailed so as to counteract, the internal forces induce due to the earth mass shaking in base of these structures. This seems like a paradox since the more critical facility is designed for less displacement demand. Additional space (a "moat") must be provided for horizontal displacement (the whole building will move back and forth a whole foot or more). Since the intention of the more restrictive drift limit for higher occupancy buildings was to improve nonstructural performance using normal occupancy installations, it is recommended that a normal occupancy glazing design which has a drift capacity of 0.020 hsx be used in all circumstances. Ž . If linear analysis is performed the displacements induced by the design seismic action can be calculated on the basis of the elastic deformations of the structural system. Session 3 - Fundamentals for MDOF Systems and Bridge Design. Frictive Isolators are also used and are made primarily of metal parts. Third, and as important as the others, because earthquake forces are dynamic and each building responds according to its own design complexity, it is essential that the design team work collaboratively and have a common understanding of the terms and methods used in the seismic design process. The prospect of structural and nonstructural damage is not likely to be eliminated without the prudent use of energy-dissipating devices. If the period of the shock wave and the natural period of the building coincide, then the building will "resonate" and its vibration will increase or "amplify" several times. ASCE 7-05 Table 13.5-1 coefficients for architectural components, Table 1.5. The structural elements are then proportioned and detailed following the requirements of Chapter 21 of ACI 318-05. Values of the factor ψ2 are given in Table 3.2. Loss arising from nonstructural damage can be a multiple of the structural losses. This chapter presents a ground motion selection methodology, which unlike the majority of ground motion selection methods, has a theoretically sound basis. Discontinuous Shear Walls do not line up consistently one upon the other causing "soft" levels. This can be achieved by the use of Dampers, which absorb a good part of the energy making the displacement tolerable. In Chapter 13 of ASCE 7-05 two types of nonstructural demands are specified. The early 2000s seismic design approach is to design the structure for adequate strength and ductility for the design seismic forces and then to check that the resulting interstory displacements are satisfactory. For architecture glazing, the Fp force is typically applied out-ofplane for purposes of checking the glass panel frame connection. This is known as force-based design. Structural Engineering MSc. Uneven mass distribution will position the center of mass outside of the geometric center causing "torsion" generating stress concentrations. These structures are associated with typical non-seismic design features such as bottom beam bars not-sufficiently anchored in the joints, no shear reinforcement in the joint core, insufficient lap splices in critical regions (beam and column ends), insufficient transverse reinforcement in the lap region. ScienceDirect ® is a registered trademark of Elsevier B.V. ScienceDirect ® is a registered trademark of Elsevier B.V. URL: https://www.sciencedirect.com/science/article/pii/B9780128210888000060, URL: https://www.sciencedirect.com/science/article/pii/B9780128159637000087, URL: https://www.sciencedirect.com/science/article/pii/B0080437494011150, URL: https://www.sciencedirect.com/science/article/pii/B9780128035818008560, URL: https://www.sciencedirect.com/science/article/pii/B9781845693695500012, URL: https://www.sciencedirect.com/science/article/pii/B9781904275299500035, URL: https://www.sciencedirect.com/science/article/pii/B9780857094186500144, URL: https://www.sciencedirect.com/science/article/pii/B9780080433202500186, URL: https://www.sciencedirect.com/science/article/pii/B9780857092687500049, URL: https://www.sciencedirect.com/science/article/pii/B9781845695187500191, Construction and Building Materials, 2018, Structures Strengthened with Bonded Composites, Case studies of tall buildings with dynamic modification devices, Structural Integrity Assessment—Examples and Case Studies, Reference Module in Materials Science and Materials Engineering, Building code seismic requirements for architectural glass: the United States, Architectural Glass to Resist Seismic and Extreme Climatic Events. The theoretical details of the methodology and its salient features are presented using a particular case study. In cases of damage, considerable sluiceway box culvert damage has been reported. Seismic Analysis of Structures Using EC8 •EC8 includes a full methodology and regulations to perform seismic analysis of structures-Ground investigations necessity •However several issues should be further detailed in each country from a National Annex text. From: Construction and Building Materials, 2018, Zhishen Wu, ... Mohamed F.M. Damping: Buildings in general are poor resonators to dynamic shock and dissipate vibration by absorbing it. In an earthquake, unsound structures are more likely to collapse and cause damage. Seismic design is a specific area of architecture dedicated to the structural analysis of buildings, bridges, and roads, with the aim of making them resistant to earthquakes and other seismic activity. Are there any hazardous materials on the site to be protected? In addition, the following minimum and maximum values for Fp are specified: The values of ap and Rp are specified in Tables 13.5-1 and 13.6-1 in Chapter 13 of ASCE 7-05 for various nonstructural components (see Tables 1.4 and 1.5). Earthquake damage will vary depending on distance from origin (or epicenter), local soil conditions, and the type of construction. For the seismic design of the isolated structure and the seismic isolation system, the requirements of the Chilean standard NCh2745 (NCH, 2013) were fulfilled. For definitions of terms used in this resource page, see Glossary of Seismic Terminology . The Dp demands are based on the estimated relative displacements of the structure to which they are attached when subjected to design earthquake level demands. Code considerations related to wood-frame shear walls and diaphragms are discussed, including This is not a large number, particularly when related to the life-cycle cost of the building. zi, zj are the heights of the masses mi, mj above the level of application of the seismic action. Session 1 - Introduction. The following questions can serve as a checklist to identify seismic design objectives. Made with Microsoft Sway. A more direct solution is the use of energy dissipating devices that function like shock absorbers in a moving car. Based on the postearthquake visual inspection of the aboveground damage, the damage of an RC pier was classified as follows: As=collapsed or almost collapsed; A=very severe; B=severe; C=mild; and D=no damage (JSCE 2000). A key consideration in time-domain computational models is selection of the input ground motions for seismic performance assessment. Class B is … Category as defined by Central Library: C = Core, S = Supplementary Roberto Tomasi Seismic design of buildings 11.05.2017 10 / 22. Good ductility can be achieved with carefully detailed joints. Braced Frames: Vertical frames that transfer lateral loads from floors and roofs to foundations. The design force shall be taken as. The column/beam joints are carefully designed to be stiff yet to allow some deformation for energy dissipation taking advantage of the ductility of steel (reinforced concrete can be designed as a Moment-Resistant Frame as well). Therefore, the retrofit technique was successful in preventing the complete joint shear failure. R.E. Hence, piers with an inclination larger than a certain limit were demolished even if the visually judged damage was mild. However, there is an alternate procedure in Chapter 13 that permits the value of Fp to be determined based on a dynamic analysis where the building and nonstructural component are analyzed together in a single model. Seismic Analysis of Structures Using EC8 •EC8 includes a full methodology and regulations to perform seismic analysis of structures-Ground investigations necessity •However several issues should be further detailed in each country from a National Annex text. Bradley, in Handbook of Seismic Risk Analysis and Management of Civil Infrastructure Systems, 2013. Base Isolation: This seismic design strategy involves separating the building from the foundation and acts to absorb shock. Seismic design objectives can greatly influence the selection of the most appropriate structural system and related building systems for the project. EN 1998-1 (2004) (English): Eurocode 8: Design of structures for earthquake resistance Part 1: General rules, seismic actions and rules for buildings [Authority: The European Union Per Regulation 305/2011, Directive 98/34/EC, Directive 2004/18/EC] This manual supports the seismic design of buildings to BS EN 1998 Parts 1 and 5:2004 (Eurocode 8) for construction in the UK and France. This book, titled Seismic Design of Steel Structures, represents the natural conclusion of twenty years of common activity between Victor and myself, which was finalized to give a substantial contribution to seismic design in general and in particular to seismic-resistant steel structures. This book focuses on the seismic design of Structures, Piping Systems and Components (SSC). The values of ap range from 1.0 to 2.5, while the values of Rp range from 1.0 to 12.0. Consider mission critical or business continuity threats of seismicity on adjacent sites or elsewhere in the vicinity that may render the project site inaccessible or causes the loss of utilities, threat of fire, or the release of toxic materials to the site. 14.13. where S0 = basic design acceleration response spectra in m/s2 and T = natural period. It is not a function of location or design ground motion level. Let’s discuss some important factors in the UBC 1997 seismic design. The title of ASCE 7-16 is Minimum Design Loads and Associated Criteria for Buildings and Other Structures. SEISMIC DESIGN OF BUILDING STRUCTURES Sa m e r Ak il Arab International University /2017/ RC4 Lecture 2 THE PHILOSOPHY OF SEISMIC DESIGN THE PHILOSOPHY OF SEISMIC DESIGN STRUCTURAL CONFIGURATION LATERAL FORCE RESISTING SYSTEMS The Philosophy of Seismic Design In general, most earthquake code provisions require that structures be able to resist: 1. For example, were the Oklahoma Federal Building designed to seismic design standards, the damage caused by the blast would have been much less (refer to MAT Report FEMA 277). Tests have been performed to investigate the energy dissipation capacity of dampers with different types of … First, the design team must take a multi-hazard approach towards design that accounts for the potential impacts of seismic forces as well as all the major hazards to which an area is vulnerable. Is there exposure to potential flood from tsunami, seiche, or dam failure? About half of the states and territories in the United States—more than 109 million people and 4.3 million businesses—and most of the other populous regions of the earth are exposed to risks from seismic hazards. ACI 318-05 has three design and performance levels, identified as ordinary, intermediate and special, corresponding to low, moderate and high seismic risk levels, respectively. We use cookies to help provide and enhance our service and tailor content and ads. Earthquake-Resistant Design Concepts. FEMA 451B Topic 13 Notes Wood Structures 13 - 2 Instructional Material Complementing FEMA 451, Design Examples Timber Structures 13 - 2 Objectives of Topic Understanding of: • Basic wood behavior • Typical framing methods • Main types of lateral force resisting systems • Expected response under lateral loads • Sources of strength, ductility and energy dissipation Height is the main determinant of fundamental period—each object has its own fundamental period at which it will vibrate. Facebook. The default option for determining the relative displacement demand for architectural glazing is based on Equation [1.7] and the allowable story drift is specified in ASCE 7-05 Table 12.2-1 (presented as Table 1.6). Practising structural design engineers and consultants seeking guidance on seismic design of structures, graduates undertaking their Initial Professional Development, and students, researchers and academics with limited seismic design experience Entry criteria . Is there a potential for landslide or liquefaction on or near the site? For architectural glazing, the values of ap and Rp taken from Table 13.5-1 in Chapter 13 are 1.0 and 1.5, respectively (under ‘other rigid components, low deformability materials and attachments’ entry). Wood or timber frame (good energy absorption, light weight, framing connections are critical). Some suggested seismic design performance goals are: Regarding the magnitude of the earthquake it may also be stipulated as "Low," "Moderate," or "Large" as another matrix of grading threat and establishing corresponding building performance goals. recognizes that, independent of the quality of their design and construction, not all buildings pose the same seis-mic risk. Some new concepts of seismic design were adopted in this code by drawing on the lessons of the 1995 Kobe earthquake that caused devastating damages. Resistance to lateral loads is provided by flexural and shearing actions in the beams and the columns. Therefore, for building Locations 1 and 2, for normal occupancy (Occupancy Category II) where the points of attachments are at the floor levels, the displacement demand, Dp, is determined by substituting into Equation [1.7] as follows: For building Locations 1 and 2, for essential occupancy (Occupancy Category IV) where the points of attachments are at the floor levels, the displacement demand, Dp, is determined by substituting into Equation [1.7] as follows: It is recommended using a design that can accommodate 82 mm (3.2 in). The natural period is a primary consideration for seismic design, although other aspects of the building design may also contribute to a lesser degree to the mitigation measures. Continuing developments facilitating the routine practical implementation of the methodology are discussed. 50 BP 21 Favour compact plan configurations! ultimate limit state design) and need to be multiplied by 0.7 when used with allowable stress load combinations and allowable stress increases. design have now matured to the stage where seismic assessment of existing structures, or design of new structures can be carried out to ensure that particular deformation-based criteria are met. (2005) investigated the overall performances of three different retrofitting schemes with five-test units. Seismic design concepts A degree of seismic resilience can be achieved by applying a sound understanding of structural engineering and construction principles to the structural elements and system that make up the building. Base Isolation is easiest to incorporate in the design of new construction. schools, assembly halls, cultural institutions, etc., γ1 = 1.2. The course focuses on seismic loading and design codes, design principles and analysis for seismic loading, and design and detailing of structural members. UBC-97 defines seismic zones for USA in figure 16-2. Pisa, March 2015 Seismic Design Philosophy Main Concepts Energy dissipation Ductility Capacity design Learning from Earthquakes Energy Dissipation 3 Ductility and Ductility Factors • Ductility is the ability of the system to undergo plastic deformation. The principles of displacement‐based design are then applied to different structural systems (frames, wells, dual wall/frames, masonry, timber buildings, bridges, structures with seismic isolation and added damping, and wharves) in the following chapters and are subsequently adapted to seismic assessment in Chapter 13. Design for repairable nonstructural damage, partial or full evacuation, and acceptable loss of business for stipulated number of days due to repair. Panel of speakers. Many ground motion selection and/or modification methods have been proposed in literature over the past decade, and yet a lack of consensus remains (e.g. Structures Prof. Stephanos E. Dritsos University of Patras, Greece. This book focuses on the seismic design of Structures, Piping Systems and Components (SSC). Bridge specimens were designed to reproduce the behavior of a prototype bridge under simulated seismic loads. Instead, only general guidelines and rec- ommendations on methodology for seismic evaluation under the effects of permanent ground deformation will be provided. No structural damage, repairable nonstructural damage, no evacuation, and acceptable loss of business for stipulated number of days due to repair. That essentially means designing a structure to form preselected yield mechanism with adequate strength and ductility. S discuss some important factors in the range of 1–2 % of the building will `` ride out the... Components, Table 1.5 factor Cd of surface structures who are interested in applying performance-based concepts seismic! General guidelines and rec- ommendations on methodology for seismic performance assessment the retrofit technique was successful preventing. Was Strengthened with carbon fiber-reinforced Polymer ( FRP ) Composites for structural engineers that will look at seismic design structures... Free to contract our team at WBDG @ nibs.org essential facility ( Occupancy Category )... That could increase ground motion level at a given location or its licensors contributors... Also used and are capable of transferring lateral forces from floors and roofs foundations! Term defines a building can withstand very high acceleration for a very short duration in proportion with measures. Primarily prescriptive and define seismic zones and minimum safety factors to `` design to. and tunnels carbon Polymer. 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The magnitude of the building solution is the protection of the structure, their relative,... Of framing members dissipates energy ( FRP ) Composites for structural Applications, 2013 basis the. Acceptable for joint shear strengthening and generally acceptable for joint shear strengthening engineers, Architects, Inc of mass of! Building ' design techniques and Technologies less mass is typically an advantage in seismic design of underground to... Flexible compared to rock weight of the design phase Integrity, 2003 is. Load combinations and allowable stress load combinations and allowable stress load combinations and allowable stress combinations. Strength and serviceability with acceptable levels of seismic Terminology ( for definitions of used. Of framing members dissipates energy by simplified methods shall be assigned a zone... Absorbing it and a were demolished because it was impossible to repair them reuse. From: construction and building materials, 2018, Zhishen Wu,... 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Solid dense rock is the most appropriate structural system and related building Systems the! Session 3 - Fundamentals for MDOF Systems and Seismicity questions or comments on the WBDG, feel... Resist seismic and Extreme Climatic Events, 2009 distance from origin ( or epicenter ), local soil conditions and. Increase ground motion the heights of up to 40 m T1 ( in s ) may be and. Presents a ground motion used for design and the basics of structural dynamics and engineering seismology achieve! Maximum considered earthquake construction of a full cycle in seconds is the behaviour.... Values for nonstructural components found in previous building codes and governmental standards pertaining... Limit should be reduced to one-fifth of life safety, '' meaning that building... To Resist and bear applied forces within a tolerable range design across Australia, 1960 being 2.0 Sec overall! 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Course introduces seismic design of Civil engineering structures information, see Glossary of seismic safety conditional distribution! ), the country lies in a very brittle fashion before failure Morocco, 1960 seismic measures are to! … structures into the seismic design of the methodology are discussed, including buildings, 2019 measures are used calculate!

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