1 / 32

ATHENS WORKSHOP / EC 8–3 : 2005 and nGCSI : 2012 APRIL 12, 2013

ATHENS WORKSHOP / EC 8–3 : 2005 and nGCSI : 2012 APRIL 12, 2013. MAIN DIFFERENCES BETWEEN THE TWO CODES M. CHRONOPOULOS, LRC/NTUA/ GR.

sugar
Download Presentation

ATHENS WORKSHOP / EC 8–3 : 2005 and nGCSI : 2012 APRIL 12, 2013

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ATHENS WORKSHOP / EC 8–3 : 2005 and nGCSI : 2012 APRIL 12, 2013 MAIN DIFFERENCES BETWEEN THE TWO CODES M. CHRONOPOULOS, LRC/NTUA/GR

  2. Assessmentand Retrofittingof existing structures for non-seismic actions is not yet covered by the relevant material-dependent Euro-Codes (or existing National Codes). • The “framework” of the EC 8-3 (and the nGCSI) was specifically developed because : •  For many older structures, seismic resistance was not considered during the original design/construction, whereas non-seismic actions were catered for, at least by means of “traditional” construction rules. • Seismic hazard evaluations in accordance with present knowledge may indicate the need for retrofitting programmes and campaings (“active” or “passive”). •  Damage caused by earthquakes may create the need for major and costly structural interventions (repair/strengthening), not to mention other consequences.

  3. DESIGN OF BUILDINGS FOR EARTHQUAKE RESISTANCEASSESSMENT AND RETROFITTING or STRUCTURAL (ASSESSMENT AND) INTERVENTIONS • The EC8-3 : 2005 Main Body/Six (short) Chapters / approx. 30 pages, and Informative Annex A for RC Structures / approx. 20 pages. • The nGCSI : 2012, for RC Structures (only), Final Harmonized Text Main Body and (Normative) Commentary / Eleven Chapters / approx. 350 pages. A new Chapter (no. 12) on Structural Additions or/and Changes of Use. Retrofitting = Str. Interventions, Repair or/and Strengthening

  4. THE RATIONALISM OF THE nGCSI : 2012, ITS CONTENTS • 1. SCOPE-FIELD OF APPLICATION-OBLIGATIONS AND RESPONSIBILITIES • 2. BASIC PRINCIPLES, CRITERIA AND PROCEDURES • 3. INVESTIGATION AND DOCUMENTATION OF THE EXISTING BUILDING • 4. BASIC DATA, ASSESSMENT AND REDESIGN + Four (4) Appendices (normative) • 5. ANALYSIS, BEFORE AND AFTER THE INTERVENTIONS • 6. BASIC BEHAVIOUR MODELS • 7. THE BEHAVIOUR OF EXISTING OR NEW RC ELEMENTS + INFILLS + Four (4) Appendices (normative) • 8. DESIGN OF INTERVENTIONS • 9. SAFETY VERIFICATIONS • 10. REQUIRED CONTENTS OF THE DESIGN FILE, ASSESSMENT AND REDESIGN • 11. CONSTRUCTION-QUALITY ASSURANCE-MAINTENANCE

  5. NOTE 1The definition of the LS of NC given in EC 8-3 is different than that given in EC 8-1.Thus, the LS of NC is closer to the actual collapse and corresponds to the fullest exploitation of the deformation capacity of the structural elements. NCEC8-1  SDEC8-3

  6. NOTE 2 • Distinction between “ductile” or “brittle”structural elements and mechanisms, i.e. deformation or strength controlled ones. See additional details and rules given by the nGCSI (μ  2 , μφ3). • Distinction between “primary” (P) or “secondary” (S) seismic structural elements, using more or less conservative estimates • of their capacities. • EC’s : S/P+S  15% • nGCSI : S/P+S  25% .

  7. EC8-3 / STATE OF DAMAGE IN THE STRUCTURE • Three (3) LIMIT STATES (LS’s), namely • Near Collapse (NC), Significant Damage (SD) and Damage Limitation (DL). • The National Authorities decide whether all three LS’s shall be checked, or two of them, or just one of them. • NC :Pe= 2% in Lt = 50 years, Tr = 2.475 years • SD :Pe= 10% in Lt = 50 years, Tr = 475 years • DL :Pe= 20% in Lt = 50 years, Tr = 225 years • _______________________________________________________ • nGCSI : DIFFERENCES …

  8. nGCSI / TARGET BEHAVIOURPERFORMANCE LEVEL, SEISMIC ACTION IMPORTANCE : I / All, II / All but C2, III and IV / A1, A2, B1

  9. Since existing structures (old ones, damaged or not) :(i) reflect the state of knowledge at the time of their construction, (ii) possibly contain hidden gross errors and problems, and (iii) may have been submitted to previous actions (accidental or not) with unknown effects, structural evaluation/assessment, structural intervention and redesign (if needed) are typically subjected to a different and a more complex degree of uncertainly than the design of new structures.Therefore, different sets of partial safety and structural safety factors are required, as well as different analysis, dimensioning and verification procedures, depending (among others) on the completeness and reliability of the information available. INVESTIGATION / DOCUMENTATION

  10. EC8-3 / Capacities of ductile or brittle structural elements • In general, mean value properties of the existing materials are used, as directly obtained from in-situ tests and from the additional sources of information, appropriately divided by the confidence factor (CF), accounting for the knowledge level (KL) attained. • Especially for brittle primary seismic elements, their strengths shall be based on material strengths divided by appropriate partial safety factors (γm), taking into account that the γm values of the EC 8-1 are meant for the design of new buildings. • nGCSI : DRL and a full set of mod. γf and γm, as well as of γSd and γRd. • Mat. properties : fm or fm – S.

  11. EC8-3 / KNOWLEDGE LEVEL (KL), CONFIDENCE FACTOR (CF) • Regarding the RC structural system, its components and its elements, for choosing the allowable type of analysis and the appropriate confidence factor values ... • Factors determining the appropriate knowledge level : • GEOMETRY • From original outline construction drawings with sample visual survey or from full survey • 2) DETAILS See Table • 3) MATERIALS See Table • ____________________________________________________________ • KL1 :Limited KnowledgeCF = 1,35 • KL2 :Normal KnowledgeCF = 1,20 • KL3 :Full (?) Knowledge CF = 1,00

  12. … outline or detailed dwgs, visual, full, limited, extended, comprehensive

  13. MIN. REQUIREMENTS FOR INSPECTION (OF DETAILS) AND TESTING (OF MATERIALS)FOR EACH TYPE OF PRIMARY RC ELEMENT (BEAM, COLUMN, WALL) Non-destructive combined with destructive testing … Cross-checks should be made between the data collected from different sources to minimize uncertainties.

  14. EC8-3 / THE q – APPROACH • Generally, not suitable for cheching the LS of NC. • For RC structures of any type : • SD q  1,5 • NCq’  4/3 . q  2,0 . • Higher values may be adopted if suitably justified with reference • to the local and global available ductility (and overstrength …). • ____________________________________________________________ • nGCSI : A lot of provisions, rules, etc. • The m – approach …

  15. THE INFILLED RC FRAMES (OR QUASI-FRAMES) • Existing or even new/added infills … • EC’s … • nGCSIA lot of provisions, rules, etc. • See a specific presentation.

  16. nGCSI : 2012 • ASPECTS OF MODELLING AND ANALYSIS • See the presentation by A. Kappos • BEHAVIOUR OF EXISTING OR NEW ELEMENTS (RC, infills) • See the presentation by M. Fardis • BEHAVIOUR OF REPAIRED/STRENGTHENED ELEMENTS(RC, infills) • See the presentation by S. Dritsos and T. Tassios • FINAL CHECKS/SAFETY VERIFICATIONS • See the presentation by M. Fardis

More Related