B Pakistan Building Code

8/10/2019 B Pakistan Building Code

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Prof. Sarosh H Lodi

Pakistan Building CodeSeismic Provisions 2007September 9, 2013

Continuing Professional DevelopmentShort Course Series

and

Aga Khan Planning and Building Services, Pakistan


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DEDICATED

TO

THOUSANDS OF CHILDREN, WOMEN AND MEN

WHOLOST THEIR LIVES

IN

THE 8th OCTOBER 2005 EARTHQUAKE


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CHAPTER 1: SCOPE

CHAPTER 2: SEISMIC HAZARDCHAPTER 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 DesignDIVISION-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 BuildingsPART 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


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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 designand construction of buildings and building-like structures and/or their

components subjected to earthquake ground motions.


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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 requirementsof 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 defenceinstallations, 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.


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Requirements of these provisions shall not be applied to thebuildings 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 CompetentAuthority.


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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.


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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 owners

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.


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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 BuildingsPART II. Composite Structural Steel and Reinforced Concrete Buildings


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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


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APPENDIX A

BACKGROUND FOR SEISMIC ZONING MAP


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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.

OVERVIEW

Seismic Zoning map is prepared on a rigorous exercise basedon 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.


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Pakistan is characterized by extensive zones of moderate to highseismicity, 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

1) Himalayan seismotectonic zone in the north,

2) Suleman-Kirthar thurst-fold belt,

3) Chaman-Ornach Nal Trasform Fault Zone,

4) Makran Subduction Zone in the west, and

5) 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.

Major Faults of Pakistan


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1. Main Karakoram Thrust

2. Raikot Fault

3. Panjal-Khairabad Thrust4. Riasi Thrust

5. Salt Range Thrust

6. Bannu Fault

7. Chaman Transform Fault

8. Quetta-Chiltan Fault9. Pab Fault

10.Allah Bund Fault

11.Hoshab Fault

12.Makran Coastal Fault

Major Faults of Pakistan

Major active faults of Pakistan and surrounding areas that strongly influencethe seismic hazard are listed below:

13.Main Mantle Thrust

14.Main Boundary Thrust

15.Himalayan Frontal Thrust16.Jhelum Fault

17.Kalabagh Fault

18.Kurram Fault

19.Ornach-Nal Transform Fault

20.Kirthar Fault

21.Kutch Mainland Fault

22.Nagar Parkar Fault

23.Nai Rud Fault
http://www.acipakistan.org/


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SEMINAR ACI CODE

After NESPAK 2006

Tirich Mir-Misgar F.MKT

MMT

Panjal T.

MBT

Raisi T.Jhelum F.

Kalabagh F.

SRT

Indus-Kohistan F

Muzafarabad T.

Kurram T.

Waziristan T.

Sulaiman Frontal T.

Kirthar F.

Pab F.

OrnachNal F.

MakranSubduction Zone

Chaman F.

Ghazaband T.

Hoshab F.

Hoshab F.

Rann of Kuchh F.

Fault Map of

Pakistan
http://www.acipakistan.org/http://www.acipakistan.org/


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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.

Seismicity


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Probabilistic Seismic Hazard Assessment (PSHA) procedure wasused for seismic hazard analysis of Pakistan - as per international

practice and guidelines for seismic hazard evaluation and seismic

hazard mapping for Building Codes.

Seismic Hazard Evaluation Procedure

Seismic activity of seismic source is specified by a recurrencerelationship, 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.

1. PSHA Methodology


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For seismic sources entire area of Pakistan was divided into seventeen

area source zones based 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

2. Source Modeling


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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 Pakistanwhich 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

3. Earthquake Recurrence Model


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To each area source zone, a maximum magnitude potential was assignedbased 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.

4. Maximum Magnitude

Due to lack of sufficient strongmotion 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.

5. Attenuation Equations


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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 ofexceedance 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.

5. Results of PSHA


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RESULTS OF PSHA -PEAK GROUND

ACCELERATION

VALUES


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On the basis of PGA values obtained through PSHA, Pakistan wasdivided into five seismic zones in line with UBC97. The boundaries ofthese 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 0.32gZone 4 > 0.32g

The seismic zoning map of Pakistan developed on this basis is shownin Fig. 2.1. Each structure shall be assigned a seismic zone factor Z inaccordance with this map or Table 5-I given in Chapter 5 of the Code.

6. Seismic Zoning


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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


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SEMINAR ACI CODE

HYDERABAD

BUILDING ANDTOWN PLANNING

REGULATIONS-

2007

???

KBCA

DHA

FC

CC

KPT


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RC Buildings


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Brick Masonry


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Block Masonry


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Adobe Masonry


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Stone Masonry


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Wood Reinforced Structures


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Others


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Building Typology

RC reinforced concrete momentresisting frame buildings

M1 Brick MasonryM2 Block Masonry

M3 Stone Masonry

M4 Adobe MasonryM5 Wood Reinforced Masonry

OO Others

Summary of Building

Typology


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Percentage of Building Types In Pakistan

62.38%14.60%

7.64%

5.27%5.19%

3.30%1.62%

Brick Masonry

Adobe Masonry

RC Buildings

Wood/Bamboo Reincorced

Stone Masonry

Block Masonry

Others


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