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Prof. Sarosh H Lodi

Pakistan Engineering Council. and Aga Khan Planning and Building Services, Pakistan. Pakistan Building Code – Seismic Provisions 2007 September 9, 2013. Prof. Sarosh H Lodi. Continuing Professional Development Short Course Series. 1. 2. DEDICATED TO

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Prof. Sarosh H Lodi

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  1. Pakistan Engineering Council and Aga Khan Planning and Building Services, Pakistan Pakistan Building Code – Seismic Provisions 2007 September 9, 2013 Prof. Sarosh H Lodi Continuing Professional Development Short Course Series 1

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  3. DEDICATED TO THOUSANDS OF CHILDREN, WOMEN AND MEN WHO LOST THEIR LIVES IN THE 8th OCTOBER 2005 EARTHQUAKE 3

  4. CHAPTER 1: SCOPE CHAPTER 2: SEISMIC HAZARD CHAPTER 3: SITE CONSIDERATIONS CHAPTER 4: SOILS AND FOUNDATIONS CHAPTER 5: STRUCTURAL DESIGN REQUIREMENTS DIVISION-I General Design Requirements DIVISION-II Snow Loads DIVISION-III Wind Design DIVISION-IV Earthquake Design DIVISION-V Soil Profile Types CHAPTER 6: STRUCTURAL TESTS AND INSPECTIONS CHAPTER 7: REINFORCED CONCRETE CHAPTER 8: STRUCTURAL STEEL PART I. Structural Steel Buildings PART II. Composite Structural Steel and Reinforced Concrete Buildings CHAPTER 9: MASONRY CHAPTER 10: TIMBER CHAPTER 11: ARCHITECTURAL ELEMENTS CHAPTER 12: MECHANICAL & ELECTRICAL SYSTEMS APPENDIX-A BACKGROUND FOR SEISMIC ZONING MAP 4

  5. CHAPTER 1: SCOPE Objective and General Principles The objective of the criteria and earthquake provisions described in this code is to prescribe the minimum requirements for the earthquake design and construction of buildings and building-like structures and/or their components subjected to earthquake ground motions. 5

  6. Scope • Requirements of these provisions shall be applicable to reinforced concrete buildings, steel buildings, building-like structures, masonry and timber buildings. • In addition to the buildings and building-like structures, non-building structures permitted to be designed in accordance with the requirements of these provisions are limited to those specified in Chapter 5. • In this context bridges, dams, harbour structures, tunnels, pipelines, power transmission lines, power generation plants including hydel, thermal and nuclear power plants, gas storage facilities, special defence installations, underground structures and other structures designed with analysis and safety requirements that are different than those for buildings are outside the scope of this code. 6

  7. Requirements of these provisions shall not be applied to the buildings equipped with special system and equipment between foundation and soil for the purpose of isolation of building structural system from the earthquake motion, and to the buildings incorporating other active or passive control systems. • Requirements to be applied to structures which are outside the scope of these provisions, shall be specifically determined by the Departments/Autonomous Organizations supervising the construction and such structures shall be designed to those provisions until their specifications are prepared by the Competent Authority. 7

  8. CHAPTER 2: SEISMIC HAZARD This Chapter defines the minimum seismic hazard that has to be considered for the design of buildings CHAPTER 3: SITE CONSIDERATIONS The selection of suitable building sites shall be carried out based upon their geology/ stratigraphy, distance from the causative fault, the liquefaction potential of site, earthquake induced land sliding, and presence of sensitive clays any other relevant geotechnical aspects, as provided in this chapter. CHAPTER 4: SOILS AND FOUNDATIONS Determination of soil conditions of buildings to be constructed in seismic zones, design of reinforced concrete, structural steel, timber and masonry building foundations and soil retaining structures shall be performed, along with the applicable codes and standards in relevant areas, primarily in accordance with the rules and requirements of this section. 8

  9. CHAPTER 5: STRUCTURAL DESIGN REQUIREMENTS This chapter prescribes general design requirements applicable to all structures regulated by this code. DIVISION-I General Design Requirements DIVISION-II Snow Loads DIVISION-III Wind Design DIVISION-IV Earthquake Design DIVISION-V Soil Profile Types CHAPTER 6: STRUCTURAL TESTS AND INSPECTIONS The owner or the engineer or the architect incharge acting as the owner’s agent shall employ one or more special inspectors who shall provide inspections during construction on the types of work listed under Section 6.1.5. 9

  10. CHAPTER 7: REINFORCED CONCRETE This Chapter contains special requirements for design and construction of cast-in-place reinforced concrete members of a structure for which the design forces, related to earthquake motions, have been determined on the basis of energy dissipation in the nonlinear range of response as specified in Chapter 5. CHAPTER 8: STRUCTURAL STEEL The Seismic Provisions for Structural Steel Buildings, hereinafter referred to as these Provisions, shall govern the design, fabrication and erection of structural steel members and connections in the seismic load resisting systems (SLRS) and splices in columns that are not part of the SLRS, in buildings and other structures, where other structures are defined as those structures designed, fabricated and erected in a manner similar to buildings, with building-like vertical and lateral load-resisting-elements. These Provisions shall apply when the seismic response modification coefficient, R, (as specified in the Chapter 5, Table 5-N) is taken greater than 3, regardless of the seismic design category. When the seismic response modification coefficient, R, is taken as 3 or less, the structure is not required to satisfy these Provisions, unless specifically required by the applicable building code. PART I. Structural Steel Buildings PART II. Composite Structural Steel and Reinforced Concrete Buildings 10

  11. CHAPTER 9: MASONRY This chapter covers the structural design of un-reinforced, reinforced and confined load bearing and non-load bearing walls, constructed with masonry units permitted in accordance with this chapter. The provisions of this section do not apply to walls constructed in mud mortars. CHAPTER 10: TIMBER Design of timber buildings or building-like structures constructed in seismic areas with load-bearing walls carrying both vertical and lateral loads as well as floors made of timber skeleton shall be performed primarily in accordance with the requirements of this Chapter. CHAPTER 11: ARCHITECTURAL ELEMENTS CHAPTER 12: MECHANICAL & ELECTRICAL SYSTEMS 11

  12. APPENDIX – A BACKGROUND FOR SEISMIC ZONING MAP 12

  13. OVERVIEW Being located close to the collision boundary of the Indian and Eurasian plates, Pakistan lies in a seismically active zone. Owing to high population density near seismically active areas, it is imperative that buildings should withstand the seismic hazard to which these may be exposed during their life time. Seismic Zoning map is prepared on a rigorous exercise based on compilation of geological, tectonic and seismicity data from Pakistan and its immediate surroundings. Only a brief account of salient seismotectonic features, seismicity and methodology adopted for seismic hazard zonation are mentioned here. 13

  14. Major Faults of Pakistan • Pakistan is characterized by extensive zones of moderate to high seismicity, induced by the regional collisional tectonics associated with Indian and Eurasian plates and resulting in manifestation of great Himalayan and associated mountain ranges. • The geographic domain of Pakistan comprises a network of active seismotectonic defined five broad seismotectonic zones • Himalayan seismotectonic zone in the north, • Suleman-Kirthar thurst-fold belt, • Chaman-Ornach Nal Trasform Fault Zone, • Makran Subduction Zone in the west, and • Run of Kutch Seismotectonic Zone in the southeast. • The Pamir-Hinukush Seismic Zone straddles across Afghanistan and Tajikistan outside Pakistan but in close vicinity of the NW Pakistan comprising District Chitral. 14

  15. Major Faults of Pakistan Major active faults of Pakistan and surrounding areas that strongly influence the seismic hazard are listed below: Main Karakoram Thrust Raikot Fault Panjal-Khairabad Thrust Riasi Thrust Salt Range Thrust Bannu Fault Chaman Transform Fault Quetta-Chiltan Fault Pab Fault Allah Bund Fault Hoshab Fault Makran Coastal Fault Main Mantle Thrust Main Boundary Thrust Himalayan Frontal Thrust Jhelum Fault Kalabagh Fault Kurram Fault Ornach-Nal Transform Fault Kirthar Fault Kutch Mainland Fault Nagar Parkar Fault Nai Rud Fault 15

  16. SEMINAR ACI CODE Tirich Mir-Misgar F. MKT Fault Map of Pakistan Indus-Kohistan F Muzafarabad T. MMT Kurram T. Panjal T. SRT MBT Jhelum F. Waziristan T. Kalabagh F. Raisi T. Chaman F. Sulaiman Frontal T. Ghazaband T. Hoshab F. Kirthar F. Hoshab F. Pab F. Rann of Kuchh F. MakranSubduction Zone OrnachNal F. After NESPAK 2006 16

  17. Seismicity • The information about earthquakes in this region have been used • based upon earthquake data from regional data catalogues • compiled by • International Seismological Centre (ISC) • National Earthquake Information Centre (NEIC) of USGS, and • from earthquakes recorded by local networks of Pakistan Meteorological Department, Pakistan Atomic Energy Commission (PAEC) and Water & Power Development Authority. 17

  18. Seismic Hazard Evaluation Procedure Probabilistic Seismic Hazard Assessment(PSHA) procedure was used for seismic hazard analysis of Pakistan - as per international practice and guidelines for seismic hazard evaluation and seismic hazard mapping for Building Codes. 1. PSHA Methodology Seismic activity of seismic source is specified by a recurrence relationship, defining the cumulative number of events per year versus the magnitude. Principle developed by Cornell (1968) is used to evaluate probability of peak ground acceleration due to an earthquake. This approach combines the probability of exceedance of the earthquake size and probability on the distance from the epicenter to the site. 18

  19. 2. Source Modeling For seismic sources entire area of Pakistan was divided intoseventeenarea source zonesbased on their homogeneous tectonic and seismic characteristics, keeping in view the geology, tectonics and seismicity of each area source zone. Eightarea seismic source zones in thenorthern partof Pakistan Hindukush, Pamir, Kohistan, Hazara, Himalayas, Salt Range-Potwar, Bannu and Punjab. Ninearea source zones insouthern part Suleiman, Sibbi, Kirthar, Kurram-Chaman, Indus plateform, Rann of Kutch, Cholistan-Thar desert, Chagai and Makran 19

  20. 3. Earthquake Recurrence Model Equations like N (m) = f (m, t) (1) Log N(m) = a – b m (2) were used with a composite list of earthquakes for areas in and around Pakistan which provided the necessary database for the computation of values for each area source zone. For data to be used in seismic hazard analysis, all the magnitudes were converted to moment magnitude (MW) by the following equations. MW = 0.67 MS + 2.07 for 3.0< MS < 6.1 MW = 0.99 MS + 0.08 for 6.2< MS < 8.2 MW = 0.85 mb + 1.03 for 3.5< mb < 6.2 20

  21. 4. Maximum Magnitude To each area source zone, a maximum magnitude potential was assigned based on the maximum observed seismicity in the historical seismic record or enhancing by 0.5 magnitude the maximum observed magnitude in the instrumental seismic record for that area seismic source zone. 5. Attenuation Equations Due to lack of sufficient strong–motion data covering a larger range of magnitudes and distances, attenuation relationships for the South Asian Region could not be developed so far. For probabilistic hazard analysis, the attenuation equation of Boore et al. (1997) along with three other equations developed during 1996 to 2004 have been used with equal weightage (25%) to each equation. 21

  22. 5. Results of PSHA The probabilistic hazard analysis was carried out by using EZ-FRISK software developed by Risk Engineering Inc. of Colorado, USA. As the purpose of the PSHA was to develop seismic hazard contour map, Gridded- Multisite module of EZ-FRISK software was used. The required parameters for all the fourteen area seismic source zones and twenty eight fault seismic sources were fed to the software. The results of the hazard analysis obtained at each grid point are presented in the form of total hazard from all the seismic sources modeled The ground motion associated with 10% probability of exceedance in 50 years (475 years return period) was calculated at each grid point. From the results obtained at 0.1 degree interval, contours of Peak Ground Acceleration (PGA) values were plotted through GIS software. 22

  23. RESULTS OF PSHA - PEAK GROUND ACCELERATION VALUES 23

  24. 6. Seismic Zoning On the basis of PGA values obtained through PSHA, Pakistan was divided into five seismic zones in line with UBC97. The boundaries of these zones are defined on the following basis: Zone 1 0.05 to 0.08g Zone 2A 0.08 to 0.16g Zone 2B 0.16 to 0.24g Zone 3 0.24 to 0.32g Zone 4 > 0.32g The seismic zoning map of Pakistan developed on this basis is shown in Fig. 2.1. Each structure shall be assigned a seismic zone factor Z in accordance with this map or Table 5-I given in Chapter 5 of the Code. 24

  25. SEISMIC ZONING MAP OF PAKISTAN Zone 1 0.05 to 0.08g Zone 2A 0.08 to 0.16g Zone 2B 0.16 to 0.24g Zone 3 0.24 to 0.32g Zone 4 > 0.32g 25

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  33. SEMINAR ACI CODE ??? HYDERABAD BUILDING AND TOWN PLANNING REGULATIONS-2007 KBCA DHA FC CC KPT 33

  34. RC Buildings

  35. Brick Masonry

  36. Block Masonry

  37. Adobe Masonry

  38. Stone Masonry

  39. Wood Reinforced Structures

  40. Others

  41. Building Typology Summary of Building Typology RC reinforced concrete moment resisting frame buildings M1 Brick Masonry M2 Block Masonry M3 Stone Masonry M4 Adobe Masonry M5 Wood Reinforced Masonry OO Others

  42. Percentage of Building Types In Pakistan 42

  43. THANK YOU 43

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