Conceptual problems for force based design using initial stiffness to represent structural response, which are often not recognized by designers are discussed. The historical basis for current seismic design philosophy is mentioned. Direct displacementbased seismic design of steel moment frames. The basis of this approach is the procedure termed direct displacement based design. Experimental study on direct displacementbased seismic. This procedure enables precastprestressed concrete buildings and other structures to be designed to respond in the designlevel earthquake to specified. Direct displacementbased design ddbd in ddbd, the design drift is the starting point, where drift is defined as the interstory displacement divided by the story height. Application of the direct displacement based design. This paper will first introduce the concepts of displacement based seismic retrofit. Displacementbased seismic design of structures session 18. Direct displacementbased seismic design ddbd priestley,1993,2000 has been developed as a simple method for designing to achieve. Pdf direct displacementbased seismic design researchgate. This procedure enables precastprestressed concrete buildings and other structures to be designed to respond in the design level earthquake to specified displacement limits, corresponding to acceptable damage limit states, while taking into. Trb webinar program direct displacement based seismic design of bridges thursday, june 22, 2017.
The paper presents an application of the seismic design method named direct displacement based design ddbd, first introduced in 1990s in the field of earthquake structural engineering, and. A displacement based design dbd procedure for buildings equipped with different seismic isolation systems is proposed. A simple and efficient direct displacement based design ddbd method is introduced to base isolated bi structures. Direct displacement based design on moment resisting frame. Performance based seismic design pbsd, which is a new concept in seismic design of structures, is a reliable approach capable of providing more detailed information on the performance levels of both structural and nonstructural elements. Seismic behavior of concentrically braced frames designed.
This article proposes a displacementbased seismic design procedure for asymmetric rc frame buildings. Design base shear of a structure is determined using design displacement spectrum. Displacement based seismic design of structures pdf. Assuming the vibration mode of superstructure to be the shear type and considering the bi structure to be an equivalent single degree of freedom esdof system with spring and damper at the seismic isolation layer. The direct displacement based design ddbd approach is spreading in the field of seismic design for many types of structures.
Constant ductility inelastic displacement ratios for the. The need for displacementbased design and analysis. For performance based seismic engineering of buildings, the direct displacement based seismic design method is different from the coefficient method used in fema273 and the capacity spectrum method adopted in atc40. Fundamentals of direct displacementbased seismic design. The fundamental problem of force based design, particularly when applied to concrete and masonry structures, is the selection of appropriate member. Direct displacementbased seismic design of flexiblebase. Assessment of direct displacement based seismic design of. Based on mode theory and direct displacement based seismic design of multistory buildings, this paper proposed a new direct displacement based seismic design procedure. The acceleration response spectrum in chinese code is converted. Pdf displacementbased seismic design of structures. This chapter presents the fundamentals of the new seismic design method known as direct displacement based design. Design displacement profile in this method is derived from the inelastic mode shape normalized based on first story displacement. Direct displacementbased seismic design ddbd priestley, 1993,2000 has been developed as a simple method for designing to achieve.
Displacementbased seismic design of symmetric single. Direct displacement based seismic design of high rise. Direct displacementbased seismic design of concrete. Within the new procedure, strength proportions between walls and frames are assigned and are used to establish the design displacement profile before any analysis has taken place.
A seismic design procedure is developed to enable concrete buildings to be designed to achieve a specified acceptable level of damage under the design earthquake. Pdf displacementbased seismic design of structures semantic. Displacement based seismic design of structures priestley pdf. This paper details a direct displacement based design procedure for steel eccentrically braced frame ebf structures and gauges its performance by examining the nonlinear dynamic response of a. The acceptable limit is defined as a displacement profile related to limit material strains or code specified drift limits. Direct displacement based design ddbd approach, which is. The purpose of this paper is the assessment of reinforced concrete building frame structures designed according to the direct displacementbased design. The key aspect of the proposed procedure is the definition of a target displacement profile for the structure. In this procedure, the elastic properties, including initial stiffness, strength and period, are the end. Analytical expressions are developed for the storey drift at yield and for the storey drift capacity of ebfs, recognising that in. Shahria alam and solomon tesfamariam, seismic performance comparison between direct displacement based and force based design of a multispan continuous reinforced concrete bridge with irregular column heights, canadian journal of civil engineering, 41, 5, 440, 2014.
Previous displacementbased design efforts were based on the direct. Pdf direct displacementbased seismic design damian. It is shown that the emphasis on secant stiffness to maximum displacement, rather than initial stiffness as in force based seismic design is important. Hence damage and displacement can be directly related.
Psycharis displacementbased seismic design 2 force based seismic design codes although the structure is designed to yield during the design earthquake, only the elastic part of the response, up to yield, is examined. High rise structures with strengthened stories are widely used nowadays. A relatively new performance based seismic design procedure called the direct displacement based design ddbd proposed by priestley and kowalsky has recently received notable acceptance among researchers. Direct displacement based design ddbd ddbd is extensively developing with the aim to correct deficiencies in analysis and design made according to, today mostly used, force based design procedures. Trb webinar program direct displacement based seismic. The analysis is based on the corresponding secant stiffness. Pdf a seismic design procedure is developed to enable concrete buildings to be designed to achieve a specified acceptable level of damage.
It is a simple design approach where the multidegreeoffreedom structure is characterized the secant stiffness and equivalent elastic damping of an equivalent. Pdf direct displacement based design based on priestley. Pdf a direct displacementbased seismic design procedure. It seems that the methods could be a rational alternative to traditional erroneous force based seismic design of structures. The method not only is a linear static procedure but also is applied to the design of new constructions. A direct displacement based design dbd procedure for structures that comprise both frames and walls is presented in this paper.
Ddbd, which was first introduced in 1993 priestley, 1993, and has. Pdf direct displacementbased seismic design semantic. This study is focussed on the evaluation of seismic performance of concentrically steel braced frames cbfs designed using direct displacement based ddbd method. Evaluation of seismic performance based on a direct displacementbased method. During the last years, seismic design of structures has experienced a reevaluation due to the introduction of new seismic design methodologies.
The scope of these can vary from comparatively narrow structural design. Particular attention is given to pulselike motions that may cause significant damage to building structures. A direct displacement based seismic design procedure of inelastic structures. Forcebased design uses an initial stiffness k i, a nominal strength f n, and an acceleration response spectrum, not shown in figure 1 based on 5% elastic damping. Direct displacementbased design of precastprestressed. This paper puts the case for direct displacement based seismic design. The applicability of the direct displacement based design dbd procedure is strictly related to a priori evaluation of the design displacement and the matching equivalent viscous damping evd of the structure. Ddbd is based on the observation that damage is directly related to strain structural effects or drift nonstructural effects, and both can be integrated to obtain displacements. In the displacement based seismic design procedure, the maximum inelastic displacement demand of structures is the most significant foundation 1, 2.
Direct displacementbased seismic design of flexiblebase structures subjected to pulselike ground motions author links open overlay panel yang lu a iman hajirasouliha b alec m. Displacementbased seismic design of structures session. Pdf direct displacementbased seismic design saadat. A rational seismic design procedure for this kind of structure is thus necessary. Pdf direct displacementbased seismic design carlos. Then, the design procedure is illustrated for two local retrofit interventions for rc frames. Seismic design of earthretaining structures and foundations. The relevance and originality of the direct displacement based design method is best. In this paper, a performance based seismic design procedure, which is directly associated with prequantified performance criteria, is presented by employing a displacement based approach.
This paper discusses the stateoftheart of displacement based seismic design dbd methods and their applications to timber buildings. Displacementbased seismic retrofit design for nonductile. This paper details a direct displacement based design procedure for steel eccentrically braced frame ebf structures and gauges its performance by examining the nonlinear dynamic response of a series of case study ebf structures designed using the procedure. Direct displacement based design for rc structures procedure, advantages and shortcomings. Direct displacementbased seismic design ddbd priestley,1993,2000 has been developed as a simple method for designing to achieve, rather than be bounded by, displacement limits that could be strain based or code driftlimit based. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. It has been derived from the direct dispaced based design ddbd method recently developed by priestley et al. On the other hand, direct displacement based design ddbd method has been proven to work well in many type of structures including mrf systems 1, 2.
The results obtained allow concluding that the structures designed according to ddbd do not necessarily exhibit better structural performance in comparison with. New equation numbering system based on subsection numbering implemented. Displacementbased seismic design of structures based design in a form similar to the maps of spectral accelerations at key defined periods seems likely to end up with mapped corner periods and peak response displacements in a data base related to gps coordinates. Direct displacementbased design requires a simplified procedure to estimate the seismic deformation of an inelastic sdf system, representing the first elastic mode of vibration of the structure. To minimize the devastating effect of earthquake on retaining structures, computation of earth pressures and the point of applications carries. A brief description of current force based design is given. Acces pdf seismic design guidelines for port structures piancseismic design performance based design of tall buildings 1 of 10 presented by ron hamburger, simpson gumpertz and heger. This paper puts the case for direct displacementbased seismic design. In recent decades, the displacement based seismic design of structures has attracted more and more attentions of the structural earthquake engineering community. A seismic design procedure is developed to enable design of concrete wall buildings in order to achieve a specified acceptable level of damages under the designed earthquake. There has been considerable discussion recently in new zealand about the relative merits of displacement based, and displacement focused force based seismic design. The structure is characterized by secant stiffness and damping at maximum displacement response, and the design forces neces.
Seismic design guidelines for port structures pianc. Direct displacement based design based on priestley and kowalsky versus force based design for wall structures. A direct displacementbased design procedure for base. Fundamentals of direct displacementbased seismic design and. The essential differences between forcebased and direct displacementbased design are summarized in figure 1. A direct displacementbased design method based on chinese. Aspects relating to characterization of seismic input for displacement based design, and to structural representation for design verification using timehistory analysis have also received special. Among them, direct displacement based design ddbd has demonstrated its effectiveness in controlling structural displacements thus controlling the likely structural damage priestley et al, 2007. In this paper, a practical displacement based framework is presented for seismic design of flexiblebase structures in nearfault regions. The objective of this study is to apply the direct displacement based design to a simple case of study, a. Ddbd has been recommended as a more rational and relevant approach to seismic design of structures compared to traditional force based design 3. It is a simple design approach where the multidegreeoffreedom structure is characterized the secant stiffness and equivalent elastic damping of an equivalent singledegreeoffreedom structure. Three techniques the capacity spectrum approach, the n2 method and direct displacement based design have now matured to the stage where seismic assessment of existing structures, or design of.
Pdf direct displacementbased seismic design of concrete. Since much of the material presented in the book has not been published elsewhere, it will also be of considerable interest. The target performance objective is to apply constraints on both the lateral interstory displacements and the top lateral displacement under the design based earthquake, which manifests the limits of displacements of. Displacement based seismic design of structures pdf, aspects relating to characterization of seismic input for displacement based design, and to structural representation for design verification using. Seismic design of earthretaining structures and foundations designs of retaining walls, earth dam, abutments, foundations, etc. In the proposed method, each mode of the high rise structure is. Development of a displacementbased design method for. A lower bound of yielding displacement of the structure to satisfy these performance criteria is proposed.
28 105 45 1281 662 1222 1507 1493 199 513 1147 1429 558 6 714 1278 1338 1456 1097 208 1412 177 980 564 1479 986 118 297 840 120 1394 884 543 1136 494 452 245 549 848 1024 794 962 611 1262 1495 614 48