M~rU.-6:tJr.y 06 Hotv.>,(ng and BHRC UJtban Deveiopment Veput.y o 6 LJ)f.ban P la.n.n{.ng ~ and AJr.c.h,(tec.twr.e. ~ BMeau 06 Stud{.v.; an.d CoMtitu.tion 06 AJtc.h-

f

I

TABLE Of CONTENTS

CHAPTER 1. GEl~ERAL

1.1. Objective 1. 2. Scope of application

1. 3. General criteria

1.4. Recommendations for design

1. 5. Classificatiori of buildings according to their i mportance

1.6. Classification of buildings according to configur ation

CHAPTER 2. SEISMIC RESISTANT DESIGN OF BUILDINGS

2 .1. General

2.2. Live Load

2.3. Seismic resistant design methods

2.3.1.Design of regular buildings

2.3.2.Design of irregular buildings

2.4. Equivalent static analysis method

2.4.1.Base shear force

?..4 . 2.Design base acceleration ( A ) 2.4.3 .Response coefficient of the building ( B ) 2.4.4 . Classification of soil types

2.4.5 . Fundamental period of vibration ( T )

Page

1

1

1

2

3

4

5

7

7

8

8

8

9

9

9

10

10

1 2

1 3

2.4.6. Impartance factor of the building (I) 13

2.4.7. Behavior coefficient of the building (R) 14 2.4.8. Vertical distribution of seismic lateral forces 15

2.4.9. Horizontal distibution of shear force 16

2.4.10.Torsional moment caused by lateral forces 16

2.4.11.0verturning 17

2.4.12.Storey dri.ft 17

2.4.13 .Seismic lateral forces on building components and added portions 17

2.4.14.Vertical component of seismic force 18

2.5. Pseudo-dynamic analysis method ( with the use of modal analysis 19 and design response spectrum)

2. 5. 1 . General 1 9

2.5.2. Number of modes of vibration 19

2 . 5 . 3 . Ba s e she a r force i n each mode of v i bra t i on 1 9

2.5.4. Distribution of base .shear force in the height of buil'ding 20

2.5.5. Maximum effect of each mode and their combination 20

2.5.6. Torsion,overturning, storey drift 21

2.6. Dynamic analysis method ( with the use of accelerograms ) 21 2.6.1. General 21

2.6.2. Use of accelerograms 22

2.7. Non-building structures (water tanks,silos,chimneys and other 22

2.8.

3.1.

3.2.

similar structures ) Combination of seismic force with other forces- design stresses

CHAPTER 3. UNREINFORCED MASONRY BUILDINGS

Definition

Limitation in height and number of storeys in the building

24

25

25

25

)

3.3. The plan of the building

3.4. Vertical section of the building

3.5. Openings ( doors, windows , cupboards ) 3.6. Bearing walls

3.7. Non-bearing walls

3.8. Parapets and chimneys

26

27

28

29

30

32

3.9. Tie beams 32

3.9.1. Horizontal.tie beams 32

3.9.2. Vertical tie beams 33

3.9.3. Tie beams of gable walls 35

3.10. Execution of masonry walls 37

3 . 11 Floors 3 8

3.11.1.Materials for floors 38

3.11.2.Connection of floor to supports 38

3.11.3.Wholeness and solidity of floors 39

3.11.4.Suspended ceilings 40

3.11.5.Arch roofs 40

3.12. Construction of facades 41

Appendix A Classification of seismic relative hazard in cities and 43

other important districts of Iran

Appendix B . Details of reinforcement and dimensions for reinforced 47 concrete frames with intermediate ductility

Appendix C Fundamental period of vibration of inverted pendulums, 50

towers , chimneys and other similar structures

Appendix D . Corrected digitized acce 1 erograms of the Ta bas ( I ran ) 5 3 Earthquake of 16th September 1978 and the Nag~an ( Iran ) Earthquake of 6th April 1977

CHAPTER 1. GENERAL

1 .1. OBJECT !VE

The purpose of this code is to determine the minimum criteria and regula-tions for the design and construction of buildings capable of withstanding seismic effects so that

a)By keeping the stability of buildings, loss of life shall be reduced to minimum .

b)Important buildings shall remain usable during the earthquake and after it .

with the observance of this code it is expected that the buildings constructed will be capable of resisting earthquakes of an intensity of up to VII degrees by the Modified Mercalli scale without any structural damage , and more sever earthquakes ( of up to IX degrees ) without co-llapsing

1.2. SCOPE OF APPLICATION

1.2 . 1.This code is applicable for the design and construction of buildings in reinforced concrete , steel , wood and masonry .

1. 2.2.The following structures are not subject to the present code : a) Special structures like dams,bridges ,Jetties, marine and off shore

structures,nuclear power plants.

In design of such special structures special criteria and regula -tions shall have to be observed to counter the effects of earthquake, but in any case the design base acceleration adopted for any particular re9ion shall not be less than that specified in this code. Unle'ss spe-cial study on the seismicity of the region is made at the structure's site in which case the result of the study shall be taken_as a basis provided that the design base acceleration is not less than ~ of the values specified in this code .

b)Traditional Buildi ng s Constructed with Adobe .

1

These buildings have little resistance against earthquake and their construction should in general be discontinued . If it becomes unavoida-ble to construct buildings of this type , they will have to be constructed in accordance with special technical instructions and by making use of some res istant elements in ti mber , and /or steel , and/or concrete and/or comb ina tion of these materials in such a manner as to render the build-ings relatively safe and resistant to earthquake

1.2.3 . Reinforced masonry buildings in which mason ry materials are used for co~pression and steel bars for tension , shall fall under the provi-si ons of Chapter 2 of this code .The structural design of this type of buildings, so long as no special regulations are made for them, should conform to approved regulations of some other country.railing this,the criteria and regulations relating to unreinforced masonry , which appear in Chapter 3 of the present code , shall a1so be applied to these buildings .

1.2 . 4. Generally , construction of buildings in the vicinity of faults should be

avoided . When this can not be avoided , apart from the observance of the provisions ~f this code, the destructive effects of the proximity of the fault should also be taken into consideration .

. 2.5. It is not allowed to construct buildings on unstable grond . By unstable ground are meant grounds in which there is likelyhood of sub-sidence , sliding and or liquefaction as a result of earthquake .

3. GENERAL CRITERIA In design and construction of buildings the following criteria shall

be observed a)All bearing elements of the building shall be suitably tied to one anoth-

er in such a manner that the various elements shall not be disjoined when earthquake occurs and the building shall behave as a unit In the case of the floor particularly, apart from solidly tying it with the vertical bearing elements - frame and or walls -should also act as a diaphragm and transmit the seismic forces to the vertical elements .

b)The building must be capable of withstanding the horizontal forces causing by earthquakes in two orthogonal directions , and in each one of these direc-

2

1 .

,

tions the transmission of the horizontal forces to the frame must be affected in a suitable manner

c)To prevent or reduce damagQ and destruction caused by the pounding from adjoining buildings , the buildings with a height of over 12 meters , or more than 4 storeys , shall be separated from each other by separation joints.

d)The minimum width of separation joints at the level of each storey shall be 1

equal to lOU of the height of that storey from the foundation. The joints may be filled where necessary , with some low - strength ma terials which will easily crus~ at the time of earthquake as a result of impact of the two buildings .

,4. RECOMMENDATIONS FOR DESIGN It is recommended to observe the following conditions in the design

of buildings : a)The plan of the building should be simple,symmetrical in both directions,

without too many protrusions and recesses . Asymmetrical change of the plan in the height of the building are to be avoided .

b)Elements su ppor tin g vertical l oads on different s to reys sho uld be placed on one another so that the t ransmission of loads of these elements to one another will not take place through the horizontal elements .

c)Elements th~t'resist the horizontal forces due to earthquake should be designed in such a manner that transmission of forces towards the founda-tion takes place directly , and elements acting together find themselves on the same vertical plane .

d)To reduce the torsional forces due to earthquake, the centre of mass of each storey and the centre of rigidity of that storey should coincide,or their distances in each one of the directions of the building should be less than 5% of the dimension of the building in that direction .

e)Construction of cantilevers more than 1.5 meters in length should be avoided

f)Placing of building elements, installations and heavy loads on the cantil-evers , slender elements and large spans should be avoided

g)Heavy loads and installations should not be placed on the upper storeys, so that the cent re of mass of the building may be located at as low as possible .

3

h)By using high strength structural materials and light weight non-structural materials , the weight of the building should be reduced to mini mum .

i)The building should be so designed that it should have high ductility. j)The building should be so designed that the vertical elements (columns)are

damaged after the horizontal elements ( beams ) .

. ~ . CLASSIFICATION OF BUILDINGS ACCORDING TO THEIR IMPORTANCE

In this code , buildings , from the viewpoint of their importance , are di vided into three groups : GROUP 1 - Buildings of great importance

This group comprises four sub-groups , as follows a)Buildings which, if destroyed , will result in great loss of life,such as

schools , mosques stadid ,cinemas,theatres,large department stores,tra-vel terminals and generally, confined spaces where more than 300 people are assembled.

b)Buildings whose serviceability after occurrence of earthquake is of special importance and whose destruction indirectly increase the number of victims and the amount'of damage in the earthquake-striken area, such as hospitals, dispensaries , fire-fighting stations, water supply centres , power stations and power transmission installations, coITTTiunications, radio and television centres,police and rescue stations and generally , all buildings of which

.

the use is effective in giving assistance and saving people's lives. c)Buildings whose destrction will involve loss of national wealth, like muse-

ums, libraries and other institutions and centres where national and other valuable documents are being kept .

d)Buildings and industrial plants and installations whose destruction will cause

,

I

1

extensive air pollution or fire , like oil refineries, fuel storage tanks and l.t gas supply centres .

GROUP 2 . Buildings of Average Importance : In this group are included buildings whose destruction will cause

considerable damage and loss of life , such as residential, administrative and cormiercial buildings, hotels, warehouses and those of industrial buildings whichare not included in group 1 .

4

GROUP 3 . Buildings of lesser importance : This group includes two sub-groups

a) Buildings likely to cause little damage or loss of life if destroyed such as forage stores .

b) Temprory buildings designed for a period of operation of less than 2 years.

1.6. CLASSIFICATION OF BUILDINGS ACCORDING TO CONFIGURATION }.6.1. Buildings are divided into two groups: Regular and Irregular.

a)Regular buildings: Regular buildings are those in which all the character-istics stated in section 1.6 . 2. are presence .

b) Irregular buildings:Buildings which are lacki ng in any one or several of the particulars mentioned in sectionsl.6 . 2.1 and 1.6.2.2 shall be considered as irregular .

1.6.2. Characteristics of Regular Buildings

1. 6.2 . 1.Regularity in plan a)The plan of the building has a generall v symmetr ical or app roxi mately symm-

etrical configuration in the main axes of the building in which, usually,the seismic resistant elemets lie in these axes directions and, if there are recesses , the size of the recess on that length does not exceed 25% of the

outside dimensions of the building in that direction .

b)ln each storey, the distance between the centre of mass and the centre of rigidity in each of the two perpendicular directions of the building does not exceed 20% of the dimension of the building in that direction .

.. 6.2.2.Regularity in elevation a)When the distribution of the mass in the elevation of the building is appro -

ximately uniform so that the mass of none of the storeys presents a va r iation of more than 50% in comparison with the mass immediately below or above it (with the exception of the attic )

b)Lateral ri gidity in each storey , first ,is not red uced by more than 30% in relation to the lateral rigidity in the three storeys below .

c.. _,

CHAPTER 2. SEISI MIC RESISTANT DE SIGN OF BU I LDINGS

2.1.GENERAL 2. 1. 1.All buildings subject to this code, with the exception of build i ngs which

are constructed with masonry materia l s and in the construction of which the provisions of Chapter 3 of the present code are observed , shall be designed in accordance with the criteria set forth in this Chapter

2.1.2.Design of a building against- earthquake and wind forces shall be m~de separately , and the effect of whichever of these forces is greater ,shall be taken into account as a basis .

2.1.3.In the aseismic design of the buildings only the horizontal component of the seismic force shall be considered and the vertical component shall not be taken into account except in the cases stated in section 2.4 . 14.

2. 1. 4. Calculations for lateral forces shall be made in two perpendicular direc-tions . In a general manner , calculations in each one of these two dire-ctions , with the exception of the buildings specified in section 2.6. 1, shall be made separately , i . e. without taking into account the seismic forces brought in the other direction

2.1.5. The seismic forces in each one of the main directions of the building shal be considered back and forth .

2. 1.6. lateral forces are to be resisted by elements such as shear walls,bracing s moment resisting frames and /or a combination of these elements .

2.1 . 7. In buildings of more than 15 storeys or 50 meters in height , constructior of moment resisting frame , capable of resisting at least 25% of the late ral forces , is ob ligatory . In the design of such buildings it must not be solely relied on shear walls or bracings for resistance to total lateral forces .

7

2.2. LIVE LOADS The live load which is taken into consideration for the calculation of the seismic lateral forces shall be a percentage of the amount of live load allowed in accordance with the building regulations in the calcu-lation of vertical load , as per Table 1.

Table 1. Live lo ad percentage

location of live load Percentage of live load Inclined roofs with a s 1 ope of 20% and more* 0

Flat roofs or roofs with a slope of less than 20~ 20

Residential and administrative buildings,hotels 20

Hospitals,schools,supermarkets and assembly

buildings 40

Warehouses and 1 ibraries 60

Reserviors of water and other liquids 100

* If there is little likelihood of the snow being retained on the roof . Other wise these roofs are to be considered as flat roofs .

.

2.3. SEISMIC RESISTANT DESIGN METHODS Three design methods are shown in this Code, as follows :

a) Equivalent static analysis method b) Pseudo - dynamic analysis method (with the use of modal analysis and

design response spectrum ) c) Dynamic analysis method ( with the use of accelerograms )

Depending on building's configuration the design method for each building shall be selected in accordance with the contents of sections 2.3.1 and 2.3.2.

2.3.1.Design of Regular Buildings Regular buildings can be designed by the equivalent static analysis

8

I l

nc

s

M ttrM m 'asr:S:= m

method provided their height do not exceed 80 meters . Regular buildings higher than 80 meters shall be designed by the pseudo-dynamic analysis method and/or dynamic analysis method .

2.3.2. Design of Irregular Buildings Irregular buildings can be designed by the equivalent static analysis

method provided thier height do not exceed 18 meters and the number of storeys are not more than 5.This method is not adequate for the design of irregular buildings which have more than 18 meters in height or more than 5 storeys.Such buildings,if they are regular in plan but irregular in elevation shall be designed by either the pseudo-dynamic analysis method or the dynamic analysis method , and if they are irregular in plan(irrespective of whether or not they are regular in elevation }, they must be designed exclusively by the dynamic analysis method

2.4. EQUIVALENT STATIC ANALYSIS METHOD In this method , the seismic lateral force is determined on the basis

of the fundamental period of vibration of the building and with the use of the design response spectrum

2.4.1. Base Shear Force The minimum base shear force in each one of the directions of a building

is calculated by Relation (2-1):

V = CW ( 2-1 )

where V= Base shear force (total seismic lateral forces in direction under consi-

deration) W= Total weight of the building (total dead load and weight of fixed insta-

1 lations ) plus some of the live load specified in section 2.2. C= Seismic coefficient obtained from Relation (2-2):

C _ ABI - ---rr

9

2-2 )

where A= Design base acceleration ( in relation to gravity acceleration g). B= Response crefficient of the building obtained from the design response

spectrum I= Importance fac~o r 0f the building. R= Behavior coefficient of the building

The C value adopted shall in no casE be less than 10% of the design base acceleration .

. 4.2. Design Base Acceleration (A) The design base acceleration for different regions of the country is deter-mined as fullows :

Region 1 2 3

Description High seismic relative hazard Intermediate seismic relative hazard Low seismic relative hazard

The above three regions are shown in appendix A .

. 4.3. Response Coefficient of the Building (B)

Design Base Acceleration

0.35 0.25 0.20

The response coeffic~ent of the building which shows the building's response in relation to the design base acceleration, is determined in accordance with Relation(2-3):

B = 2.0 (

where

To T

2/3 ) (2-3)

T= Fundamental natural period of vibration of the building in seconds , mentioned in section 2.4.5.

To= Figure which is given in the Table below , according to the type of soil .

10

--

l i

01 c: ......

" ...... ......

=' ..0

'+-0 +.J c: di ......

u Sl ......

'+-'+-di 0 u

di Vl c 0 c.. Vl

2.4.4.Classificati on of Soil Types

I Soi l

I Type

I I

I I L I II

I

I

IT I I

I

The t ypes of soil me nt ioned in secti on 2. 4.3 are described i n Ta ble 2 .

Table 2. Soil Types

Description

a) Ig neous rocks (C ourse and fine grained texture), hard and st iff sedimentary rocks and massive metamorphic rocks ( Gneisses-c rystall ine silicate rocks ) .

b) Conglomerate beds , compact sand and gravel and stiff clay( Argillite ) beds up to 60 me ters from the bed rock.

a) Loose igneous rocks (such as tuff), friable sedi mentary rocks , foliated metamorphic rocks and the rocks which ha ve been loosened by weathering .

b) Conglomerate beds , compact sand and gravel and stiff clay(Argillite) beds where the soil thickness exceeds 60 meters from t he bed rock.

a) Rocks which have been disintegrated by weathering b) Beds of gravel and sand with weak cementation and /or uncemented

unindurated clay ( clay stone ) where the soil thickness is less 10 me ters from the bed rock.

than

~, ~~+--~------~~----~~-~~---~~~~--~~~~~~~--~~~~--~-

' IV

a)Soft and wet depos its resulted from high level of water ta bl e . b) Gravel and sand beds with weak cementation and / or uncemented ,

unindurated clay ( clay stone ) where the soil thickness exceeds 10 meters from the bed rock .

1 2

l If there is doubt as to the conformity of the soil at construction site with the specifications of any of the soil types in the above Table,the type chosen shall be the one that offers a greater response coefficient.

2.4.5.Fundamental Period of Vibration (T) The fundamental period of vibration , depending on the characteristics of the building, is determined with the use of empirical Relations(2-4), (2-5)and(2-6) :

a) Generally, for all buildings with the exception of cases stated in paragraph (b)

H T = 0 .09 Vo ( 2-4 )

3/ 4 If the value obtained from relation (2-4) is greater than 0.0611 , the latter shall be taken as the fundamental period of vibration .

b)For buildings with moment resisting frames , if other building elements do not creat ao obstacle to the movement of the building frame:

3/4 (i) For Steel Frames T=0.08H (2-5)

3/4 (ii) For Reinforced Concrete Frames T=0.07H (2-5) In the above relations His the height of the building from the base level, and D is the dimension of the building in the direction under consideration, both in meters .

Instead of using the empirical relations , the fundamental period of vibrations of the building can be calculated by using the dynamic analysis method on the basis of the characteristics of the structure and the defor -mation of its resisting elements but in any case the fundamental period adopted shall not be more than 1.25 times the period obtained by the relatins empirical relations .

2. 4.6.Importance Factor of the Building (I) The importance factor of the building is determined in accordance with the classification given in section 1.5, as follows :

Building Classification Group 1 Group 2 Group 3

1 3

Importance Factor 1. 2 1.0 0.8

2.4. 7. Behavior Coefficient of the Building (R)

! I I

2

3

The behavjor coefficient of the building represents the building's capability to absorb energy, and reflects numerous factors including materials.damping , type of structure and ductility capacity of the building, as given in Table 3 .

Table 3. Behavior Coefficient of Building

I System of Structure

Bearing Walls System: in which the walls support all or the most parts of the vertical loads,and resistance to seismic lateral force is provided by shear walls.

Simple Space Frame System: fn which the space frame with simple connections supports all vertical loads, and resistance to seismic lateral forces is provided by shear walls or bracings.

Moment Resisting Space Frame System : in which the space frame,alone,supports a 11 vertical loads and seismic lateral forces (whi'thout shea; walls or bracings).

Lateral Force Resisting System

a) Reinforced concrete shear walls

b) Reinforced masonry shear walls

a) Reinforced concrete shear walls

b) Bracfngs c) Reinforced masonry shear walls

a) Steel moment resisting space frame

b) Reinforced concrete monent resis-ting space frame

R

5

4

7

7 5

6

5

4 :combined System of Moment Resisting Space a) Moment Resisting frametre1nforced B Frame and Shear Walls or Bracings : In this system the space frame supports the vertical ~oads,a~d resistance to seismic lateral forces is provided jointly by the space frame and the shear walls or by the space frame and the bracings The seismic lateral forces are .distributed between the space frame and the shear walls pr between the space frame and the bracings in proportion to their rigidities but in any case the frame alone should be capable of supporting at least 25% of the seismic lateral forces""

concrete shear walls

b) Moment resisting frame+ bracings 8

1 4

'

...

* If the criteria of intermediate ductility stated in Appendix B . are observed, a coefficient of 6 may be adopted

**In buildings of up to 8 storeys or shorter than 30 meters, 100 percent of the seismic lateral forces can be supported by shear walls and bra-cings , by doing so,comparison of rigidities of the resisting elements may be neglected provided that frames are capable of resisting at least 30 percent of the seismic lateral forces .

~EMARK 1.If the building have a high ductility according to the crit-eria of a different code, the behavior coefficient (R) can be taken as_ 8 -~or the system mentioned under i tern 3 and as 10, for the system mentioned under item 4 . So lo ng as the said code has not been prepared and ~pproved , the criteria of high duc-tility may be taken from some valid code .

REMARK 2.Use of flat slabs and flat plate~ as a system mentioned under item 3 , is permitted exclusively in 3 storey buildings or shorter than 10 meters . If the building exceeds this limit, this system can only be used if resistance to seismic lateral force is provided by shear walls or bracings

2.4.8. Ve r tical Distribution of Seismic Lateral Forces The base shear force calculated as per section 2.4.1 is distributed over the height of the building in accordance with Relation (2-7):

in which

w. h . l l

n 2= w.h. J=l J J

Fi = La t e ra 1 force at 1eve1 i ,

( 2-7)

w;= Weight of the level i i nc luding weight of the Floor and its live load according to section 2. 2, one-half of the wei ght of walls and of the columns situated above and below the floor.

hi= Height of level i from base l evel. n = Number of storeys

! I I I

Ft= Additi onal lateral force at the level of the nth storey of the buildi ng whic h is dete rm ined by means of Relation (2-8):

(2-8)

Maximum force Ft is taken to be equal to 0.25V and if T is equal to 0.7 seconds or less, Ft may be taken as zero

2.4.9. Horizontal Di s tribution of Shear Force In each storey, the shear f orce shall be distributed to the various elements of t he vertical late ral force resisting system in propor.tion to their rigidities .

2.4.10.Torsional Moment Caused by Lateral Forces

2.4.10.1.All buildings, with the exception of those metioned in section 2.4.10 .2 shall be calculated against the effects of the tors ional moment according to this section . The torsional moment in storey i is obtained from Relation (2-9) :

(2-9) .

where e . . = Horizontal distance between centre of rigidity in storey i and

1J centre of mass at level j.

Fj =Lateral force at level j. Ta = Accidental torsional moment which is considered to take into acount

the probable of accidental changes in the distribution of the mass. This moment shall be taken in both directions and at least equal to the product of the shear force in storey i and 5% of the dimension of the building in the same storey in the direction perpendicular to the lateral force Each of the elements must be calculated for the torsional moment which creats the most sever loading in that element .

:2.4.10.2.In the case of buildings having 5 storeys or less with a maximum height

I

t 16

of 18 meters, if the horizontal distance between the centre of mass of the higher storeys in relation to the centre of rigidity of each storey is less than 5% of the dimension of the building in that storey in the direction perpendicular to the lateral force, calculation against the torsional moment is not obligatory. Otherwise the building shall be des-igned for torsion but the accidental torsional moment in such buildings may be disregarded

2. 4.11. Overturning The build i ng must be stable against overturning . The overturning moment at level of the base caused by the seismic lateral forces is equal to the sum of product of the lateral force at each level L and the height of that level in relation to the foundation - soil interface of the building .

i Factor of safty against overturning (relation of resisting moment to the overturning moment) shall be at least equal to 1.7.5 .I.n the calculation of the resisting moment the equilibrium load is equal to the vertical load which is used to determine the lateral force , and the weight of the foundation and of the back fill on it is added to it .

2.4 . 12. Storey Drift lateral displacement at each level of the building in relation to

the upper or the lower level, which is calculated by taking into account the lateral forces jointly with the torsional momer.t, shall not exceed 0. 005 of the height of the building.

2.4.13. Seismic lateral Force on Building Components and Added Portions Building components and portions added to the building shall be desi gned against the late ral force which is obtained from Relation (2 -1 0) :

(2-10 ) in wh i ch A and I are the values stated in sections 2. 4 .2 and 2.4.6 respectively,which ha ve been used for the design of the en tire building. WP is the we i gh t of t he buil ding component or added part and porti on under consi dera t i on .In tan ks and racks ?f warehouses and libra r ies Wp,in add ition to the

.. .

of the s t orage dead

l L j I ,_

~ I I

load, shall also include their contents when completely full. BP is the coefficient given in Table 4 .

Table 4. B values p

Building Components or Added Portions Direction of Horizontal force

Outer and inner walls of the building, Perpendicular to wall surf ace and rartition walls

Parapets and cantilever walls Perpendicular to wa 11 surf ace

Outside and inside ornamental elements Any direction or components of the building

Reservoirs ,towers,chimneys,machinery Any direction and equipment if attached to the buil-ding or made part of it,and suspended ceilings

Connections of prefabricated structural Any direction elements

REMARK For building components constructed in masonry and sand - cemen~ m.ortar, the tensile stress of up to 15 percent of the compre-ssive strength stated in section 10.5.1 of Standard No.519 of Iran should be taken into account in calculations .

2.4.14. Vertical Component of Seismic Force

BP 0. 7

2.0

2.0

1.0

1.0

For cantilevered balconies and projections of the building the vertical component of the seismic force shall also be considered . The vertical component for these elements shall be determined by Relation (2-11):

in which

F = v 2AI

Rv ( 2-11)

A and I are the values stated in section 2.4.2 and 2.4.6 which are considered for the calculation of the base shear force .

l L

n 1 GFffim o sa t m rtetrw -

r a sttz cm

~,,.;.._,=-- :- ~-:- ~'"

'.(' ,~ ,'' ~ -. ' . ' ~ ' .~ -~ ~-~--,-:c

t I I

v = c m m Wm (2-12)

r ABm (2-13) '"'m = R

2/3 Bm 2. 0( To ) = (2 -14) Tm

n 2 L_ w. a. J Jm j=l w = (2-15) m n 2 ~ w. a . J=l J Jm

in which Vm =Base shear force in mode m, Cm =Seismic coefficient in mode m , Wm =Effective weight of building in mode m , Bm =Response coefficient of building in modem , Tm =Period of vibration in mode m , ajm=Displacement of level j in mode m , wj =Weight of level j A,l,R,To = The same values stated in section 2. 4.

2.5.4.Distributio,n of Base Shear Force in the Height of Building Th~ late~al force at level by the following'Relations

and in modes of vibration m is determined

F;m = C;m Vm (2-16)

Wim aim c. = im n

(2-17) L wj a jm j=l

?.5.5.Maximum Effect of each Mode and their Combination By using the base shear force and its distribution in the height of the building , the required responses in each mode ( like shear, moment, displacement etc .), are obtained .The value of each response in various

20

modes shall be combined with each other, and the building shall be designed against the joint effect of the modes. In this Code, the combination of joint effect of the modes is taken to be equal to square root of the sum of squdres of the maximum effect of each mode. If the total base shear force obtained in this manner by combining the base shear force of the modes is less than the value which is obtained in accordance with section 2.4.1, the latter value shall be taken as the total base shear force and the other responses which have been calculated in each mode shall also be increased in the same proportion .

2.5.6.Torsion , Overturning , Storey Drift

Design of the building against torsion , overturning mome nt, and control of storey drift shall be made in the manner stated in section 2.4.10 2.4. 11 and 2.4.12. The seismic lateral force for the building members and co~ ponen ts shall be considered in accordance with section 2.4.13, and the seismic vertical componen t ,in accordance with section 2.4.14 . .

2.6.DYNAMIC ANALYSIS METHOD (WITH THE USE OF ACCELEROGRAMS)

2.6.1.General

ThP. dynamic analysis method (Time history calculation of responses of the building under the influence of actual earthquake accelerogram ) may be applied to all buildings. Generally,in the case of buildings which are perfectly regular or buildings which are regular in height,if this method is to be used it can be applied separately in the two perpendicular dire-

ctions However, if the building is irregular in plan to such an extent that its vibrations in some or in all modes mainly take place jointly in two perpendicular directions , i.e. if the building has modes of vibra-tion in which movement in one direction takes place together with movement in a direction perpendicular to that direction , in such a case ,in order to take into account this joint movement, the buildings must be designed by the dynamic analysis method ,with the use of a three dimensional model.

21

2.6.2.Use of Accelerograms

In the dynamic analysis method, the building must be subjected to the direct influence of the horizontal components of the accelerog r am of each one of the two earthquakes ment ioned below which are chosen as basic earthqua kes

these components have a higher maximum accelerati on between the two recorded horizontal components of each accelerogram ):

1- The Tabas (Iran) Earthqua ke of 16th September 19 78 2- The Naghan ( Iran ) Eart hquake of 6th April 1977

a~d in the case of each response ,whichever of these two earthquakes has a greater effect ,shall be taken as a basis for design. The corrected digitized accelerograms of the two earthquakes mentioned above are given in Appendix D.

if at any future time an earthquake occurs with a max imum horizontal accele-ration of more than 50% gravity acceleration and is declared by the Building and Housing Research Centre as basic earthquake, and the corrected digitized accelerograms are published, the effects of that earthquake on the building shall also have to be considered.

2.7.NON-BUILDINGS STRUCTURES (WATER TANKS, SILOS, CHIMNEYS AND OTHER SIMILAR STRUCTURES)

2.7.1.Structures of this type which have similar structural systems to the systems stated in Table 1 shall include in the regulations of section 2.3 of this code .

2.7.2.Seismic lateral forces affecting these types of structures if not included in sections 2.7.1 and 2.7.3, shall be determined by using one of the methods stated in section 2.3 and with the observance of the following regulations :

a)Period of vibration of these structures shall be determined by using dynamic analysis method .Fundamenta l period of vibration of inverted pendulum, towers and chimneys shall be obtained using the relations

22

I l

stated in Appendix C .

b)lf fundamental period of vibration of these structures exceeds 0.5 seconds, use of pseudo-dynamic method is obligatory.

c)The behavior coefficient R for these structures shall be determined according to Table 5. The ratio -i- shall not be less than 0.5.

d)Structures of which the fundamental period of vibration is less than 0.06 seconds are considered as rigid and their B value shall be

R 0.5.

e)Lateral force distribution in the height of these structures,depen-ding upon the case , shall be done by the method stated in section 2.4.8 and /or section 2.5.3.

f)The drift limitations,subject to section 2.4.12 is not observed in the case Qf these structures unless structures' damage and/or its

.

non-structural factors involve loss of life . l 2.7.3.Seismic lateral forces affecting ground or underground tanks shall

be determined by the use of one of the following methods L a)These structures are considered as rigid and regulation of section

2.7.2. shall be observed with regard to them. In determining the I seismic lateral forces,the total weight of the fluid contained in

l the tank and its own weight shall be included in the calculation of w.

b)The behavior of these structures is determined by using a known dyn-ami c analysis method in which the motion of the fluid contained in the tank is considered at the time of earthquake, and seismic lateral forces are determined by taking into account the design response spectrum and design base acceleration stated in this code .

23

Table 5. Behavior coefficient (R)

I te~ Type of Structure R

1 Structures which have similar behavior to inverted pendul um ,aerial 2.5 tanks on braced or unbraced legs

2 Sil os,chi mneys,cooling t owe rs and generally, dist r ibuted ~ass can-tilever structures which have si milar behavior to vert ical cantil-evers .

3 Hoppers and bines supported on braced or unbraced legs

4 Trused towers and stacks (Freestanding or guyed )

5 Signs,billboards ,special amusement facilities and children playgrounds and monument towers

6 Other structures

4.0

3.5

3.5

4.0

3.0

2.8. Combination of Seismic Forces with Other Forces-Design Stresses

If the structure is designed by the working Stress Method, Criteria stated in the Standard No. 519 of Iran shall be used as a basis.If the structure is designed by the Ultimate Strength Design and/or Limit State Design Method combination of the seismic forces with other forces shall be done with obse-rvance of the criteria stated in the applied code .

24

d

L

l l l

CHAPTER 3. UNREINfORCED MASONRY BUILDINGS

3. 1 . DEFINITION By masonry buildings are meant buildings constructed

with bricks, cement blocks and stone, in which all or part of the vertical loads are supported by masonry walls. Therefore. buildings in which part of the vertical loads is supported by masonry walls and part by steel or reinforced concrete elements shall be considered as masonary buildings ~nd the regulations stated in this chapter shall also be applicable to such dual type buildings .

3.2. LIMITATION IN HEIGHT AND NUMBER OF STOREYS IN THE BUILDING

3.2.1. In masonry building the maximum number of storeys, not counting J the basement , is limited to two , and also, the level of the

building 1s roof sha 11 not be higher than 8 meters from the aver-age level of the adjoining ground , otherwise it shall be count-ed as one of the storeys of the building.

3.2.2. The rrcximum height of a storey ( from the lower horizontal tie bea~ to the lower surface of the floor) is limited to 4 meters. If tr: height of a storey exceeds this limit , an extra horizo-ntal ~ie beam shall be provided in the walls at a maximum heig-ht o: 4 meters from the lower tie beam ,in addition ~the tie be-ams s:ated in section 3.9.1. In this manner , the height of the store1 may oe increased to a maximum of 6 meters .

25

I I

l I t

1

3.3. THE PLAN OF THE BUILDING 3.3.1. Generally , the plan of the building must have the following

characteristics: a) The length of the building shall not be more than three

times its width. b) The building shall be symmetrical or nearly symmetrical 1n

the two main axes . c) The building shall not have unsuitable projections and

recesses .

3.3.2. If the length of the building exceeds the triple of its width or if it is asymmetrical or its projections exceed the prop -ortions stated in section 3.3.3. , the building shall have to

be divided , by providing joints as per section 1.3.d, into more suitable sections so that each section shall conform with characteristics given in section 3.3.1.

II D '

I =iD iD OCJD

Figure 2. Division of the building into suitable sections by providing joints .

26

l

1

l 1 l

I ..

l

3,3.3. The dimensions of projections in the plan of the building , wi -thout providing joints , are limited to the proportions shown in Figure 3.

Tb I ~ < 815 18 ._____! >_b L

a) Projection along the lenght of the building

b) Projection along the width of the building

3. 3. 4.

3. 4. 3.4 .1.

Figure 3.

If in Figure 3(a) b) : or in Figure 3 (b) 1 > + then these parts shall not be considered as projections and in this case there shall be no li mitation for the other dimension pro-vided that the plan of the building is not being asymmetrical.

As far as possible , the walls shall be located in a regular and symmetrical configuration in the plan of the building so that, by uniformly resisting the horizontal seismic force , they shall reduce the torsion created in the building to the minimum .

VERTICAL SECTION OF THE BUILDING It is generally preferable that a building should have no proje-ctions in the vertical section. If projections exist , the foll-owing regulations have to be observed : a) The length of cantilever projections in the case of balconies

open on three sides should not exceed 1.20 meters, and in the case of balconies open on two sides , 1 .50 meters , and the cantilever must be securely anchored in the floors or within the walls . If the cantilever length exceeds the above limits then it must be ca lculated agains7_ .:r.e 1e:C.H: a; scsrric force in accordance

27

with section 2.4.4. b) Projection of the building in vertical section , in a manner,

that the upper storey protrudes in cantilever ahead of the lo-wer storey, is only permitted if the following conditions are observed :

i) The length of the projecting part ( cantilever ) be not more than 1.00 meter.

ii) The structure of the projecting part be so designed that none of its walls is made to bear the load of the floor or or the upper walls .

iii) The walls of the protruding be supported by vertical tie-beams of steel or reinforced concrete with suitable conne-

r ctions ' and both ends of the tie beams be securely tied in the structural elements of floors.

' ~

The tying beams shall be constructed in such a way that,first, each tie beam supports a maximum of 2 meters of wall, second , on the two sides of windows having a width of over 2 meters , there will also be tie beams.The minimum cross section and reinforcements of these vertical tie beams shall be in conformity with the vertical tie beams of the building , stated in section 3.9.2.1 and 3.9.2.2.

3.4.2. Construcion of floors of different levels in one storey should as far as possible be avoided . If difference of levels exists , the walls between the two sections with different levels shall be reinforced by suitable additional tie beams , or the two parts of the building shall be separated by a joint.

3.4.3. The foundation shall as far as possible be constructed on the same horizontal level . If owing to sloping ground or other reasons , the foundation can not be constructed on one level , then each part of it shall be constructed on one level clined foundations is to be avoided

and in any case construction of in-

3.5. OPENING (DOORS,WINDOWS,CUPBOARDS) 3.5.1. In general , providing wide openings in masonry buildings shall be

avoided .As far as possible, the openings shall be placed in the central part of the walls .

28

r

I 1-

1-I L

I L

3.5.2. The Following Restrictions Are Obligatory : a)The total area of openings in each bearing wall shall not exceed

of the total area of the wall .

1 3

b)The total length of openings in each bearing wall shall not exceed j of the length of the wall.

C)The distance of the first opening in each external bearing wall of the building shall not be less than-~- of the height of the opening,unless vertical tie beams are provided at both sides of opening

d)The horizontal distance of two openings shall neither be less than -} of the height of the smallest opening of its both sides nor less than

~ of the total length of the two openings . Otherwise, the part of wall between the two openings shall be considered as part of the openings, it shall not be counted as bearing wall and the lintel shall be considered as being in one piece of which the span is equal to the combined length of the two openings plus the wall between them .

e)None of the dimensions of the openings shall be more than 2.5 meters. Otherwise , hoth sides of the openings will have to be strengthened by vertical tie beams connected to the horizontal tie beams above and below that storey and both ends of the lintel of the opening shall be solidly attached to the vertical tie beams on the sides of the opening .

3.6. BEARING WALLS

3.6.1. The wall-ratio in the longitudinal and transversal directions of the building , for each storey, shall not be less than the values given in Table 3. The wall -ratio of each storey, in each dire -ction , is the ratio of the horizontal section area of the parallel walls in the direction under consideration to the area occupied by that storey . For the determination of the wall - ratio any of the walls having a thickness of 20 centimeters or more which have horizontal tie beams at the floor level shall be tak-en into account . The walls above and below the openings shall not be considered in the calculation of the wall-ratio . In other words , to determine the wall-ratio , the lesser horizontal cross section giving the minimum area of the wall shall be taken into consideration .

29

Table 3. Minimum values of wall-ratio in each

direction of the building

Type of Building and Number of Storeys Basement First Second Floor Floor

1 - Storey 6% 4% Brick Buildings -2 - Storey 8% 6% 4% 1 - Storey 9% 6%

-

lstone or Cement Block Buildinqs 2 - Storey 12% 9% 6%

3.6.2. The maximum permissible length of a wall between two supports is 30 times its thickness(A support is a wall which intersects the bearing wall , from another direction ). The minimum thickness of such a support shall be 20 centimeters, and its length , counting the thickness of the bearing wall, shall be at

1 of the largest span at both sides of the support . 1 east 6

3.6.3. The height of the bearing walls shall be in conformity with section 3.2. 2.

3.7. NON -BE ARING WALLS AND PARTITIONS 3.7.1. The maximum permissible length of a non-bearing wall or partition

between two supports is 40 times the thickness of the wall or pa-rtition,and or 6 meters whichever is smaller . The supports shall have at least the same thickness as the wall, and their length shall be at least l of the largest span at bo-th sides of the support . The suppor~s may be replaced by elemen-ts of steel , reinforced concrete or wood placed in the wall or partition . Both ends of these columns shall be fixed and fastened in a sui-table manner to the floors of the storey .

3.7.2. The maximum permissible height of non-bearing walls and partiti~ns from the adjoining floor is 3.5 meters . If the height exceeds

30

"" "& -. t d: me e-aa ~- ttami=r?' m,. i5't'!"5H!M3i'Fm

l this limit , the wall or partition shall be suitably reinforced by providing horizontal and vettical tie beams .

L 1 1 L

1

3.7.3. Partitions rising to the entire height of the storey must be pro-perly sealed under the ceiling , i.e. the last course of the par-tition must be inserted by pressure and with sufficient amount of mortar into the gap between the top of the partition and the cei-1 ing. The upper edge of the partitions which do not rise to the entire height of the storey must be properly tied to the surrounding tie beams or to the structure of the building by means of steel , reinforced concrete or wooden tie beams .

3.7.4. The vertical edges of partitions should not stay free and exposed. They should lean against another partition or wall perpendicular to it , to the structure of the building or to a steel , reinfor-ced concrete or wooden column provided for the purpose and be

------properly fixed to such supports.The column may be a 6 centimeter steel- da~;l- ~~ -its equivalent in steel , reinforced concrete . or wood. If . the length of the supporting partition is less than 1.5 meters , its edge may be left free.

3.7.5. If the wall and the partition leaning aginst it are constructed simultaneously or by the 11 Lariz 11 or 11 Hashtguir 11 method , the bonding of the partition with the wall shall be considered as su-fficient , but if the partition is constructed after the wall and without bonding with it, then the connection must be ensured by placing in the mortar between the brick courses, at the place of connection,steel bars of 8 millimeters in diameter (or equivalent steel plates ) which extend at least for 25 centimeters into the wall and 50 centimeters into the partition . Such steel bars or plates , fixing the Partition to the wall must be provided at least at 60 centimeter inter-vals.Otherwise,the vertical edge of the partition shall be considered as free and unsupported,and a column must be provided at this edge as indicated in section 3.7.4.Two orthogonal partitions must be bonded together .

3 1

-

I 3.8. PARAPETS AND CHIMNEYS I_ 3.8.1. The height of parapets around roofs and balconies from the adjacent fi-

nished floor , if the thickness of the wall is 10 or 20 centimeters, I shall not exceed 50 and 90 centimeters respectively . Should their hei-

ght exceed the above limits, the parapet shall be supported by vertical I steel or reinforced concrete elements ,and suitably fixed in the floor l of the roof or balcony . I_ 3.8.2. Chimneys.traditional aeration tower and similar elements shall not rise

Gore than 1.5 reters above roof level . Should their height exceed I the above limit , they shall have to be suitably strengthened by verti-

cal steel or reinforced concrete elements and onchored to the roof .

3.9. TIE BEAMS 3.9.1. Horizontal Tie Beams

3.9.1.1. In all masonry buildings whether of one or two storeys,and irrespective of whether they are constructed in bricks ,cement blocks or stone , tie beams must be provided at the levels stated below :

a)At the level under the walls . This tie beam shall be constructed in reinforced concrete in such a way that its width shall not be less than the width of the wall or 25 centi-

. 2 meters , and it~ height not 1 ess than j- of the width of the wa 11 or 25 centimeters . It is not obligatory to construct tie beams under partitions unless such tie beams are necessary for connection to the main tie beams

b)At the floor level , on bering walls . The floor tie beam , if constructed in reinforced concrete shall have the same width as the walls except in the case of external walls where, for the purpose of facade construction , the width of the tie beams may be made 12 centimeters less than the width of the wall , but in any case the width of the floor tie beams shall never be less than 20 centimeters. The height of tie beams on bearing walls and shear walls shall not be less than 20 centimeters but their height on non-bearing walls may be reduced to 12 centimeters. In the floor ,12 centimeter steel I beams may be used instead of reinforced concrete tie beams provided that the

32

' .1

L 1 l_

l J. _1

t _l

J

steel tie beams are solidly fixed to the beams of the floor and also suitably anchored and tied to the walls.

3.9.1 . 2. The minimun diameter of longitudinal steel bars in horizontal reinforced concrete tie beams shall be as follows :

3.9.1.3.

12 millimeters for deformed bars and 14 millimeters for plain bars. The number of longitudinal reinforcing bars shall be at least 4 and shall be placed in the corners . If the width of the tie bea~ is more than 35 centimeters , the number of the longitudinal bars shall be in-creased to 6 or more so that the distance between two adjacent bars shall not exceed 25 centi meters . The longitudinal bars shall be tied to each other by means of ties with steel bars of 6 millimeters in di_ ameter . The maximum distance of these ties from one another shall be 20 centi meters or the height of the tie beam , whichever is less. The concrete cover over the longitudinal bars shall be at least 5 ce-nti metersfor the tie beams under the walls , and 2. 5 centimeters for the fl oor tie beams .

At every level , the sides of the tie beams sha 11 be connected togeth -er so that the tie beam system shall form a network in which all the tie beams are interconnected . The reinforcements at the intersection of tie beams shall be well executed , particularly in the case of floor tie be-ams , so that the connection will be well and reliable . The flo or tie beam shall at no point be separated . If the floor t i e be-am i ntersects chimneys , air conditioning ducts , cooler ducts and other si mil ar facilities , arrangements shall be made to ensure proper connec-tion of the tie beam on both sides of such facilities .

3.9.1 .4. If a masonry building has also columns of steel or rei nforced concrete , the c olu~ns shall be suitably connected , in the upper end to the floor eleme nts , and in the lower end to the tie beams under the walls .

3.9.2. VERTICAL TIE BEAMS

3.9.2.1. Vertical tie beams shall be provided' in all two - storey masonry (

buildings as well as in one-storey buildings of great importance (Group 1, mentioned in section 1. 5 ). Vertical tie beams shall be

Provided withjn the walls , in the main corners of the building and preferably also at the intersections of walls . The distance between axes of two tie beams shall not exceed 5 meters. None of the dimensions of the cross section of tie beams shall be less than 20 centiMeters.Reinforced concrete tie beams may be replaced by 10 centimeter steel I beams or other equivalent steel sections provided the tying of the steel tie beams to the wall is properly done by means of steel bars .

3.9.2.2. The minimum diameters of longitudinal steel bars in vertical re-inforced concrete tie beams are 10 millimeters for deformed bars and 12 millimeters for plain bars . The numb er of longitudinal steel bars shall be 4 at the minimum , and they shall be placed in the four corners of the tie beam. The longitudinal steel bars shall be tied together by means of ties with steel bars of at least 6 millimeters in diameter.Maximum distance between such ties shall be 20 centimeters . On the longitudinal steel bars there shall be a cover of at least 2.5 centimeters of corcrete .

I- 3.9.2.3. The vertical tie beams shall at all intersection points be suit-j ably connected with horizontal tie beams so that they will join-1 tly form a three.dimensional resisting system I I j_ 3.9.2.4. Instead of the vertical tie beams described in section 3.9.2.1

I I I

l I -

above , steel bars may be distributed along the walls as shown in Figure 4 provided that

a)Sand and cement mortar be used for the construction of the wall The minimum amount of cement shall be 200 kilograms per cub ic meter of mortar .

b)Material around the bars be placed so as to submerge the bars, and the vertical joints be completely filled

c) The distance between two steel bars be not less than 60 centimeters . d) The vertical steel bars at distances of at least 25 centimeters be an-

chored together with the hori zonta 1 bars of 6 millimeters in diameter. e) Around each vertical bar, a space , of which the smallest dimension is

34

- - - --=-

l

at least 6 times the diameter of the bar , be left open and filled s1-mul taneously with mortar during construction of the wall .

f) The vertical bars be anchored in the horizontal tie beams above and below .

3.9 . 2.5.In one-storey buildings of average importance (Group 2 described in section 1\5 ) it is recorrrnended that the vertical tie beams be cons-tructed in accordance with sections 3.9.2.1 or 3.9.2.4. Otherwise , at least in the location of the vertical tie beams of such buildings mentioned in section 3.9.2.1, there should be placed one deformed steel bar of 12 millimeters in diameter with due observance of the conditions stated in section 3.9.2.4 (a),(b),(e) and (f) .

3.9.2.6.Construction of vertical tie beams as stated in sections 3.9.2.1 and 3.9 . 2.5 is not obligatory for one-storey buildings of lesser import-ance ( Group 3 described in section 1.5 ).

3.9.3. Tie Beams of Gable Walls In ~uildings covered by trusses and inclined light roofing it 'is pre-ferable to place trusses also on the end walls . Otherwise , the triangular part of these walls shall be strengthened by tie beams as described below :

a) ~t the base of triangular shaped end wall , in the level of the tie beams below the supports of the trusses horizontal tie beams are to be provided and these tie beams shall be fixed to one another .

b) The upper surface of the triangular wall is to be covered by tie beam so that the surface above the tie beam shall be parallel to roof cover , and the lower surface shall be in the shape of steps .

c) Between the two tie beams on the top and at the base of the triangular pa-rt of the wall , vertical tie beams shall be provided at maximum 5 meter intervals . The steel bars of the vertical tie beams shall be fixed in the lower and upper tie beams .

d) The dimensions and steel bars of the tie beams referred to in (a)and (b) above are subject to the criteria relating to horizontal tie beams (section 3.9.1.) and those of the tie beams referred to in (C) above are subjected to the criteria stated for vertical tie beams in section 3.9.2.

NOTE

Min. 60 Min.60 Max. 120 Max.120

6 ( c~o-:7.Zs

J-' 0 ~ .--~~~~~~ ' .....

. .

c:: >< x ~

~ 12 ~ 10

0 0 N

' .....

c: >< ~ .., ::E: ::E:

Qt] Min

t B= . . . . ---- h Min Min.60 I M~ I Min.60 Min.120 Max.120 Mix.120

Fiqure 4.0etails of vertical and horizontal steel bars anchored in the walls .

_J

~ 0 0 N '

.....

c >< ~ ~ ::E: ::E:

: ..

. I

1. The longitudinal bars of vertical tie beams shall be bent at both ends to ~n angle of 90 degrees and anchored in the tie beams of

36

- -~-'

foundation and floor . 2.As masonry work progresses , mortar shall be placed around the verti-

cal reinforcement bars . 3.The mortar for the wall shall be sand and cement mortar( minimum of

200 kilograms cement per cubic meter of mortar).

3.10. EXECUTION OF MASONARY WALLS 3.10.1. Use of mud mortar or mud and lime mortar is not permitted in masonry

j_ buildings . WQlls of stone or cement blocks shall be constructed with sand and cement mortar with a minimum quantity of 200 kilograms of cement per cubic meter of mortar . In brick walls , apart from sand and cement mortar , mortar made of sand and lime , with a mini-mum amount of 250 Kilograms of lime per cubic meter of mortar er lime-cement mortar with 100 kilograms of cement and 125 kilograms of lime per cubic meter of mortar may also be used . Parapets of roof and balconies and the part of chimneys protruding outside of the

l. L l

building must be constructed exclusively with sand and cement mortar made with a minimum of 200 kilograms of cement per cubic meter of mortar .

3.10.2. Walls made of stones shaped on rectangular blocks or of cement blocks shall be executed in such a manner that vertical joints do not coin -cide with each other, and completely filled with mortar . In Hall s of rubble stone , the stones shall be laid in a manner to ensure their bonding with each other and the interfaces between the stones shall be completely filled with mortar .

1 3.10.3 . As far as possible , all bearing walls connected to each other,parti -cularly in the corners of the building , shall be constructed simultaneously at each level and raised uniformly everywhere . such simultaneous construction is not possible , parts of the may be constructed by the method locally called 11 Lariz 11 and

Where walls

the subsequent parts laid on the 11 Lariz 11 In the case of the bearing walls , making them in the shape of dentate, in the manner locally called 11 Hashtguir 11 and used to ensure connection of cross walls or

37

I_

L L l J

L

in the construction of long walls , is not allowed . The 11 Hashtguir" method may solely be used for the construction of partition walls provided the upper and lower joints of the subsequent brick courses are cowp letely filled with mortar .

5.11. FLOORS

3.11.1. Materials for Floors Floors shall be constructed with suitable materials and in a manner that wh en exposed to the seismic forces , they will , first , not become separated from their supports and , second , will remai n whole and unshattered. Use of wood as the bearing element is permitted when the roof cove-ring is made of light material like boards, iron sheets , co r rugated meta 1 or asbestos cement sheets , and in such cases wood may a 1 so be used for the tie beaming of the floor . Construction of wooden roofs with a cover of mats or reed and with mud or mixture of mud and lime or sun dried brick placed over them is not permitted .

3.11.2. Connection of Floor to Supports The floor elements ( beams and joists, whether of steel ,con -

. crete or wood ) or the concrete slabs shall be securely connected and fixed to the.supports under them ( bearing beams horizonta1 tie beams, columns) so that the seismic forces brought on the floor shall. without displacing it , be transmitted to the vertical ele-ments. To ensure this , the following criteria must be observed :

a) In the case of floors supported on bearir.g beams, the main elements of the floor shall be attached to the bearing beams , and these shall in turn be attached to the tie beams on the walls .

b) In the case of floors resting on the walls , if the floor is const-ructed by using steel I beams and brick jack arches , the steel I beams of the floor must either be anchored in tne reinforced con -crete tie beams or be welded to steel plates placed and secured on the longitudinal tie beams,or else be tied to the steel tie beams in a suitable manner.The length of the support of tile steel treams in this type of floor shall not be less than the height of the steel

38

I beams or 20 centimeters . If the floor is made of precast con -crete slabs , it is preferable t~at the precast slabs be anchored in the horizontal reinforced concrete tie beams . Simply placing the precast slab on the tie beam is to be avoided unless it can be anchored to the tie beam on the wall in a suitable manner .The composite floors of joists and blocks must also be ade-quately anchored to the horizontal tie beams and the pouring of co-ncrete of the joists and tie beams shall take place at the same time. Cast-in-situ re~nforced concrete floors must also have a support at least equal to the thickness of the wall minus 12 centimeters pro-vided this length is never less than 15 centimeters .

c)The structural elements of staircases also , on the bendings which are level with the floors of the building shall be anchored in the tie beams of the floor .

3.11.3. Wholeness and Solidity of Floors The following conditions shall be observed to ensure that the floor acts as a whole body :

3.11.3.1.Brick - Jack Arch Floors a)The steel beams shall joined to one another by means of steel bars

or plates placed diagonally in such a way that, first, the length of the criss- crossed rectangle is not more than 1.5 times of its width and , secondly the area covered by each criss-crossed element is not more than 25 square meters

b)A suitable support is to be provided for the heel of the last span of arches . This support may be created either by placing a steel I beam and fixing it to the tie beam beneath or by anchoring in the reinforced concrete tie beam. If this support is in steel ,it must be fi xed , by means of straightened steel bars or rods , at both ends of the beam and also at intervals of less than 2 meters,to the last steel beam of the floor

c)The minimum cross-section of the steel bar or plate used for diago-nal bracings of the floor beams or for the fixing of the last span shall be that of a oar of 10 millimeters in diameter or an equival-ent plate .

39

3.11.3.2 . Blocks and Joists Floors : a)The concrete covering the blocks shall have a minimum thickness of

5 centimeters and the amount of bars in the direction perpendicular to the joists shall not be less than 1 square centimeter per meter. The bars shall be so placed that the intervals between them are not more than 30 centimeters .

b)If the spans of joists are more than 4 meters , they shall be joined by transversal bars to the reinforcement steel in a suitable manner.

3.11.3.3.Trusses a)The wholeness and solidity of the floor is ensured by providing ver-

tical and horizonal bracings . b) The various parts of wooden trusses shall be solidly attached to each

other at the joints by means of bolts and nuts or of steel clamps { attaching these parts by simply nailing them to each other is not sufficient).

c)In inclined flat roofs , if the covering is not in the form of truss-es , suitable elements have to be provided to withstand the thrust of the roofing .

3.11.4. Suspended Ceilings Suspended ceilings shall be made of light materials and their framing shall be attacheq in a suitable manner to the structure or tie beams of the building so that the impact of the seismic shocks will not da-mage the adjoing walls .

3.11.5. Arch Roofs Construction of arch roofs is conditional upon the observance of the following criteria :

a)Making necessary provisions to minimize the thrusts and to ensure that the roof can withstand them . The walls must be properly anchored

b)Construction of reinforced concrete tie beams at the he~ls{ imposts of the roof , so that the arch roof can be placed on the tie beams in a suitable manner.In cylindrical arches the two sides of the sprin-ging tie beam shall be connected to each other by means of steel tie rods placed and tied beforehand in the tie beams.The distance between

40

these tie rods shall not be more than 1.5 meters and the cross -section of the tie rods shall not be less than the value obtained from the following relation

L x 0 A = ----s 2

Where L is the span of the arch , D is the distance between the tie rods ( both in meters } , and A is the section of the tie rod in square cent-

s imeter

3.12. CONSTRUCTION OF FACADES 3.12.1. In the construction of facades with bricks it is preferable that the facing

bricks should be placed at the same time with the rest of the wall. The thickness of the facing bricks and of the bricks used in the wall should be equal or nearly equal so that the courses of both kinds of brick may be laid on the same bed of mortar. If the facing bricks are placed after the wall behind it is constructed , connection of the two kinds of brickwork will have to be ensured by placing the free ends of the bars in the mortar of the courses of facing bri cks.The distances of these connecting bars in both hori -zontal and vertical directions shall not exceed 50 centimeters .

3.12.2. Construction of facades in stone which is not in the form of plates, and when the stones are placed on each other horizontally , shall conform to the criteria stated for brick facades in section 3.12.1. If the stone in the form of plates are placed vetically then their fixing to the wall behind them is to be ensured by means of clamps or some other suitable type of attachment to prevent their falling off at the time of earthquake

4 1

,f:o-N

~ )I " Sat .. lc !oa ''" of IMM USSR

1nt-rr1

..,, , ; ... .,1111111 I \ 1

.. ~1 111 ''~'" Soect1l1 for Shtc leshtant Oeitqn o r lu11d1"9 1 Sttuiote "'O "'O n> ::s Cl..

-)(

)>

I I

1 J

-'

-- - - - - --- a,_ --

Appendix A Classification of seismic relative hazard in cities and other important districts of Iran

I t~ City or District Province * .. * H I L

( A ) I Abadan 2 Abadrh 3 Aba r kouh 4 Abbasabad S Ab9a nn (Avaj) 6 Abhar

Aghjari 8 A9hda 9 Agh-Ghaleh

10 Ahar 11 Ahram 12 Ahwaz 13 A lamdeh 14 l .ulouyeh IS Aliabad-Gorgan 16 Al19 cicarz 17 Amo1 18 Anr 19 Anarak 20 And i l'leshk 21 Ar1< 22 Arda 1 23 Ardrt:1 l 24 Ardekan ZS Ardrstan 26 Asta r a Z7 Ava j

I l 3

Babol Ba bcl sar

Baf~~ 4 Ba 't 5 BaJ estan 6 Ba ~giran 7 Balhtaran a e ....

( 8 )

9 Bandar-Abbas 10 Bandar-Anzai! 11 Bandar-0,ylam 12 Ba ndar- Imam

l ~o~e i ni

Khuzts tan rars

rars

Khorss an Zanjan Zanjan Khuzestan Yud II.land, ran z East Azarbaijan Bushehr Khuzestan Hazandara n Bush,hr Hazandaran Lores tan Haza ndaran Yu d Is fahan Khuzes tan Ha rkaz 1 Chanraha l-Bakhti a n East AzarbaiJan Yazd I sfahan Gil an Zanjan

Hazandaran Mazandaran Yazd Kerman U1orassan Khorassan Bakhtara n Ke man HorMOzgan Gf lan Bushehr Khuas tan

x

x

x

ltttn Cfty or District

13 Bandar-Gaz 14 Bandar-Khamir IS Bandar-Lengueh 16 17 18 19 20 21 22 23 ;>4 zs 26 27 ZB Z9 30 31 32 33 34 35

Bandar-Turkman Baneh Bastn Bastam Buman Behabad Behbahan Behshahr Bryar joma n Bi j ar Airjand Boeen 'Zahra Bojnourd Borujan BorouJen BorouJerd Boshrouyeh Bos ta n

Bostanabad Bushehr

( c ) Chah-Bahar

2 Cha lous 3 Charak 4 Chenara n

2 3 4

s 6

8 9

10

Oamavand Oamghan Otrab

( 0 )

Oar an oar,hgu Oarrthshahr Oasht-e-Bayu Oehak Oehbid Oehloran

Provf net

HaUndaran Honnozga n Hormozga n Ha zandnn

H

Kurdesun Hormozgn x s,innan S1stn-8tluchestan Yazd a Khuzestan x Haztndtrtn a Stmna n a Khurdesun Khorasun JI Za njan JI

x Khorassan Bushehr Cha.,..hal-Bakhtiari Lores tin x Khoras san x Khuz estan East Azarbaijan i Bus hehr

S1stan-Btluchestan x Hazandar tn Horinozgan Khorassan

Tehran Se'Man rars

lsfahan Khorassan I lam

x

x

x

x

x

Khorassan Sist1n-Saluchest1n x fars x I lam x

* H, I ,L High,Interr.iediate and Low seismic relative ha za rd respectively

43

..

L

I

11 12 13 IC lS 16

2

Otll jan Oryhook Oez fu l Oogonbadan Ooroud Oorounrh

Eghli d Eivantkry

3 Eshrayen t Eshtehard

F1rashband 2 Far lman 3 F1 r ouj 5 6 7 8 9

F1rsan Fashm fasu Ftrdows f'I rou za had Ftrouubad

10 f'l rouz kouh

1 2

Gachsaran Ga nos1r

l Gel fon Gen1veh S Ge nal

6 'hnn 7 Gllnm !lhahr

( E )

( F )

( G )

8 C>111ruhtddin 9 Cllnrt Shlrln

10 Ghuv ln 11 12 13 14 15 16 17 18 19

GhorYth 'huhln 6>1 1 r Gh090 Ghoeshth Ghouch1n Golkf Golp1yt91n Gonab1d

20 Gonba'1-K1vous

Provinc t

Marka zl Khorassa n Khuztstan

H

x

x

Kohk llouyth-Boytr Ahnad Lorts tan Khorassan

Fars Stmnan lhohssan Tehran

Firs Kho rusan l horasun (harll'~ha l-8akhtl1rl Tthran Fars Khorusan Fars East Azarbal j an Tthran

.

x

x

x

x

x

l(

l ohkilouyth-Boyrr Ahlllad x Stftltla n Kho,.ass1n Bushrhr Eas t Azarbaljan Khorassan Mlzandaran Wtst Aza rltaij an Bakhtar1n hnj an lurdutln Honroz91n Firs Marku I Is hhan 1Chor1ss1n hraan l sf1h1n lhorusan ~zandarin

x

x

x

L

44

It"' City or Oistrlct Province H

Zl Gor91n 22 Cova ttr

l 2 3

s 6

Haftgue l H1j llbad Hamadan H1shtp1r Htndlj1n Hovryah

111 .. I ra n Shahr

l lshhan lzeh

2 3

s 6

J 1hr()rl J 1 nda~h J 1lr 19h. Jask Jfroft Ju l fl

( H

l I

( J

2 3

hboutara hang hkhk kahnouj

4 Ka ngan S Karaj 6 Kas han 7 Kas >vnar 8 Kueroun 9 ICtrlll n

10 IChaf 11 lh1 lkha l 12 13 IC IS 16 17 18 19 lO 21

1Ch1nur l ha rk lhlSh KhOll\tl n lhonj Khe r l ho rr111111 b1d Khorr& Shahr lhoy Kish

Haza nd1ran Slstan-8aluchtstan x

Khu a sun Hormozgan Hainada n Glhn Khuzutan Khuzuun

x

x

111111 Slstan-81luchestan x lsflhan Khuztstan

Fars x Yud Slslln-81luchtst1n x Hormozgan Kt rm.in

East Aza rba ljan

Ha1!14 dan IChorasun lt n"la n

Bushrhr Teh ran lsfahan Khora su n F 1 rs Ktrm.in

Khorassa o Ent Azarba l jan lsflh1n

x

x

x

Bushrhr Slsta n-Baluchtstan Harku I Fars x Yazd Lorutan x Khuztslln West Az1rb1fjan x Honnozgan x

L

x

x

22 lonual 23 ICouhak 24 ICou hba nan 25 1touhp1yth 26 1Couhran9

H

Slst1n-81luchtst1n a Slst1n-81luchtstan a ltenqn l

?7 ICushke Hosrat Tthr1n

la hi Jan 2 lll" 3 LI van 4 Lorde9an

Ha ha bad 2 Mahallat J HahrQud1!:>1d 4 Ml h Shallr S Maku 6 144 hyer 7 Har19~t~ 8 Marand 9 Mara veta pp eh

10 Ma rd abad 11 Marlvan 12 Mar vd a s~t 13 Mashhad

( L

( H )

14 MasJed Soleynan lS Mehran 16 MeshU n Shahr 17 M1aneh 18 Miandoa!:> 19 Mlnab 20 Hlrjaveh

1 Maten 2 Ha9h1~e~ 3 H1 9>11n 4 Ha havand 5 Naibal'ld 6 Hajafa !:>ad 7 Hatanz 8 Ht1SNbour 9 Ntyr11

10 lllk Shahr 11 lloHltlbad lZ llo11r

( N

l

Honno191n x Ct'19nnaha 1-8akht hrf 1

\lest Azarb1iJ1n ""'1rkazl ""'1zand1ran IChuzu tan lltst Azerbai j an Ha.-.adan East Azar ba lj a n East Azarbaijan "4zandar1n Tehran ICurd ts tin ran

Khorassan Khuzestan Ihm East Azarbalja n East Azarba1jan ll est Azarba 1j a n Mor-Tr()zg an Slstan-Baluchest an

lsfahan

I

x

x

\lest Azarbal j a n Charmahal-Bakhtlarl l Ha-adan Kennan I sfahan lsfahan i::horassan Fars

x

x

Sistan-Baluchesta n x S'stan-Baluchtsta n ""'1za nda r an

l

l

l

l

x

45

It.- City or District

1 J llour1b1d (Hu .. sanl) 14 Now Shahr

0 Oroumlyth

p 1 Parubad 2 P1ran Shahr l Pole Dokhtar 4 Polour

Rafsanjan 2 Ramur 3 Rasht C Rav1r S Rey 6 Roblt

( R )

7 Robate Poshte Bad1m 8 Roshtkhar 9 Roudehtn

10 Roudsar

Sabzevar 2 Sa9h1nd 3 Saghu

( s )

4 S1lafche9an

S S1 l 1111s 6 S1n1ndaj 7 Sarab 8 Sar1khs 9 S1rav1n

10 Sarbu 11 Sarchuhmeh 12 Sar i 13 Saveh 14 St':leh IS Stm1rom 16 St

I tttn City or ~1strict Province H L

25 Shlrvan Khorassan 26 Shushtar Khuzes tan JI 27 Shhchtshl!'e~ West Azarbatj1n l 28 Sirch Kennan JI 29 SirJn Kennan lt 30 Sousa ngerd Khuzes tan lt 31 Sul tan I yell Zanj an l

( T ) l hbu Khoras san l 2 T1br1z Ent Azarba I J a n lt 3 Ta fresh M1rkaz1 lt 4 T 1heri Bushehr lt 5 Takab West Azarba i Jan 6 Tayebad Khorassan

7 Tehran Tehran

e TI ran lsfahan

9 Tonekabon Muandaran

10 Torbat Heydarfyeh Khorassan lt 11 Torbat Jui Khora s san JI 12 Toroud Semnan 13 Touyserk1n Hamadan

v ). V1r1mfn Tehran JI

w

West ls lama bad Bakhtaran JI ( y

1 Yasuj Kollkiluyeh-Buyer Ahmad 2 Yazd Yazd

( l )

Z1bol S1stan-8~1uchestan

2 Zlbol 1 Sf stan-81luchestan

l Z1hed1n Sist1n-8aluchest1n 4 Zlnjan Z 1nj an

5 Zlrand Kerman lt

;

46

l

L L L l L L L L

Q .. .. Appendix 8 -----~~~~- ~.

zr, '\ 0 c!,, f' j ) ~ .. , 1 f.1l92

Details of Reinforcement and Dimensions for Reinforced Concrete Frames 1 (! with Intermediate Ductility

A.2.1. To provide intermediate ductility for reinforced concrete moment resisting space frames the following reinforcement details shall be observed in beams columns , flat slabs and flat plates. Reinforcement details in columns shal be as beams if axial load acting on columns is less than 0.1 fc Ag in ultim-ate strength design (0.07 fc Agin working stress design ) method .

where f = 28-day compressive strength of concrete based on strength of a(l5x30) c

centimeters cylindrical concrete sample . Ag= Gross area of section in square cen.timeter.

A.2.2. The design shear force of beams,columns , flat slabs and flat plates shall be obtained for one of the following shear force values :

a)Shear force caused by difference in bending moment of the ends of the member plus shear force caused by vertical and lateral loads provided that bending moments of the ends of the member are taken to be equal to the positive and negative bending strength of the member at supports. In determining the shear force caused by the difference in bending stre-ngth of the member at supports shall consider positive bending strength in one side and negative bending strength in another side , and vise versa.

b)Shear force equal to the combination of shear force caused by vertical load and twice the shear force caused by lateral force.

A. 2. 3. Minimum strength of concrete (fc) shall be equal to 200 kilograms per I l square centimeter and maximum yield strength of steel shall be 4200

kilograms per square ceptimeter.Reinforcement bars must be of deformed type.

A.2.4. Details of beams

47

I Ii .2.4.1.The following limitations shall be observed in determining the cross -sectional dimensions of beams : ,_ a) Effective depth of beams shall not be more than -} of its clear span.

b) The width-to-depth ratio of the beam shall not be less than1~ ,and/ or less than 25 centimeters . ~

c) The width of beam shall not be more than the width of the supporting column (measured on a plane perpendicular to the longitudinal axis of the beam )plus i- of the depth of the beam on each side of the column. '~ \ I ~ d) The width of beam shall not be more than the width of the supporting column(measured on a plane perpendicular to the longitudinal axis of

the beam) plus ~ of the dimension of the column in the longitudinal axis of the beam on each side of the column .

.. 2.4.2.Eccentricity of the beam in relation to the axis of the column shall be more than -!- of the width of the supporting column .

A.2.4.3.Positive reinforcement on each support of the beam shall not be less than } of the negative reinforcement of the beam in that support .

1.2.4.4.Neither the negative nor the positive reinforcement at any section along the length of the beam shall be less than ! of the maximum positive and negative reinforcement at supports .

1.2.4.5.Stirrups spacing at both ends of the beam over a length equal to twice the beam depth shall not exceed

a) { of the beam depth b)Eight times the diameter of the smallest longitudinal bars . c)24 times the diameter of the stirrup bars .

The first stirrup shall be located at not more than 5 centimeters from the face of the supporting member.Stirrup spacing in the re~t of the beam length is limited to one-half of the beam depth and to 30 centi-meters at maximum.

48

I !-I

~

A.2.5. Details of Columns ; r

A.2.5.l. The following limitations shall be observed in determining the cross-sectional dimensions of columns :

a)None'of the cross-sectional dimensions shall be less than 25 centime-ters.

b)The clear length of be more than 25 .

column in relation to its cross-section shall not

I L A. 2. 5.2. Tie spacing at both ends of the column over a length equal to the maximum value : _l_ of the length of the column,maximum cross-sec -

6

L tional dimension of the column,and/or 50 centimeters , shall not exceed : a )O ne-half of the smallest cross-sectional dimension of the column.

l _ b)Eight ti mes the diameter of the smallest longitudinal bars . c)24 times the diameter of the tie bars.

L l l L

Column ties shall be continued to the beam depth with the same spacing. Tie spacing in the rest of the column is limited to twice the above

I

values and 30 centimeters at maximum .

A.2.5.3. Longitudinal bars in the column shall not be less than one percent of the cross-section of the column .

L A. 2.6. Details of flat slabs and flat plates L A.2 .6.1. All required reinforcements for transfer of bending moment from slab

to column shall be concentrated in the column strip .

1

A.2.6 . 2. Not less than ~ of the required rei nforcement for transfer of bending moment from slab to columns and not less than -} of all required reinforcements in the column strip shall be concentrated , in the width, f rom slab equal to column width plus 1.5 times the slab thickness on each side of the column

A.2.6 . 3. Not less than ~ of the negative reinforcement at the supports in the column str ip shall be continuous throughout the span .

4 9

A.2.6.4. Not less than ~ of the negative reinforcement at the support in the column strip shall be used as continuous positive reinforcements in the column strip.

A.2.6.5. Not less than 1 of all positive reinforcement at mid-span of all strips shall be continuous up to the supports and completely anchored.

Appendix C .

A.3 . 1. Fundamental period of vibration of a concentrated mass located at the top of a slender cantilever (if mass of the cantilever is neglected ) is obtained from Relation(A.3.1):

T='21r~{p: (A.3.1) in which P= Weight of the oscillating mass k=-} f= Displacement of the top of cantilever caused by the action of a

. ' unit load at the top g='Gravity acceleration

A.3.2. Fundamental perioQ of vibration of a concentrated mass located at the top of a cantilever with uniform section ( if mass of the canti-lever is not neglected ) is obtained from Relation (A.3.2) :

T=2,.. ~ in which ' 33 1 p=p+ 140 q

p=Weight of concentrated mass q=Weight of the unit length of cantilever l=Length of cantilever g=Gravity acceleration E=Modulus of elasticity !=Moment of inertia of the section

50

(A.3.2)

...

., t -4 . .

I ,. .. ..-... -- . _.......... ___ _,__ ___ _

l A.3.3. Fundamental period of vibration of a 'prism with constant section along the height is obtained from Relation(A.3.3):

I j in which

1= length of prism q= Weight of the unit length of prism I= Moment of inertia of the section E= Modulus of elasticity g= Gravity acceleration

(A.3.3)

J A.3.4.Fundamental period of vibration of a truncated cone is obtained from Relation ( A.3.4) :

l I I l

2 _g_ ~-T= k 1 gE I in which L=Distance from C to the cone base a=Distance from C to the top of the truncated cone l=Height of the truncated cone q=Weight of the unit length at the cone base(section AB) !=Moment of inertia of the cone base

L k=The value obtained from the following: L a 0.4 0.6 0.8 I.O

k 1.29 1.5 1.7 1.79

(A.3.4) c

0

t 8

A.3.5.Fundamental period of vibration of concentrated masses along the length of cantilever

(

L

I a)Assuminq that the structure has rotated 90 degrees about the gravity field: ...

1

L

l

if x1 , ~ , ... xn are values of displacements caused by different masses and deformations remain within the elastic limit,fundamental period of vib-ration is obtained from Relation (A .3.5):

J IPX 2 T-2 ... 1 1 - g,P. x.

L 1 1

(A.3.5) 1 51

b} If high accuracy is not required , fundamental period of vibration can be obtained from the following : Assuming that the structure is located at the level of the last mass under the influence of a unit force : if x1 , x2 , ... xn are values of displace-ments of different masses under the influence of this force,fundamental period of vibration is obtained from Relation (A.3.6) :

(A.3.6) ')T;J_ 2 IP x. T=2 r ; , gx

n

A.3.6. Fundamental period of vi~ration of steel chimneys a)Steel chimneys with uniform section

Fundamental period of vibration of these chimneys is obtained from Relation (A.3.7)

(A.3.7)

in which l=Height of chimney in meters q=Weight of unit length of chimney in kilograms per meter g=Gravity acceleration in kilograms per square centimeter E=Modulus of elasticity in kilograms per square centimeter . !=Moment of inertia of chimney's section about the axis which

passes through the centre of chimney, in meter to the power 4.

b)Steel chimneys with truncated cone shape Fundamental period of vibration of these chimneys is obtained from Relation {A.3.8.)

in which

T= 2 r ~ 0 .080 g {A.3.8)

D=Lateral displacement of the top of the truncated chimney { in meters )under the influence of lateral force equal to the total weight of the chimney.

g=Gravity acceleration in meters per square second

52

' J II' ,. J T Appendix Di . ..

TA BAS EARTHQUAKE SEP 16. 1978 (1357/6/25) COMPONENT N16W IIURATION=2S.OO SECONDS PEAK VALUE=915.39 CM/SEC/SEC "'. b' P ._. COr . 4 0 - :1.4. / ' 4 2 .50 -3 :1.. :1.6 "> c-,., ._ .~ ._ - 1 2 .75 2. ~;4 - 6.90 ? . ~:i6 14. 3:::; :? 58 2 4.71 2.60 , 5.74 2.62 -22.06 ::.> c. 4 -- 3B. 28 2 . 66 -36 .85 2.68 27.17 2.70 50.68 ;~. 72 ~-:;3 . ? B 2 . 7 4 14.01 2.76 -26.74 2.78 -68.76 2 .80 -32.70 2 . 82 2 0.62 2.84 2 1.96 2.86 - 1.53 ? .88 -- 1. 3 . ()~) 2 .90 -1 6.91 2.92 23.86 2.94 54.13

:~. 96 33.58 2. 98 11.96 3.00 -20.26 3.02 -27. 17 ~L0 4 - 7 . 39 3 .06 l.5.42 3.08 25.58 3.10 - 9.8El 3 .12 "/ 3.22 20.46 3 .24 - 9.31 3.26 -55.85 3 . 28 - 2 1.4 1.-, 3.30 -9.25 3.32 18.37 3.34 2.24 3 .36 -- 1~5.37 3 . 38 -3 .84 3.40 -3.50 3.42 -19.14

3.44 --23. 60 3 .4 6 -1 .48 3.48 12 .11 3.50 4.99 ~~. ~2 3 .96 3,54 1 3 .14 3.56 -8.30 3.58 -35.72 3 . 60 12.:1.0 3.62 35.30 3.64 22 . 1 l. 3.66 8.42 3.6B -l.6.25 3.70 -29 .65 3 . 72 - 43. 33 3.74 -3.07

l :~ . 7 6 ~. 2 0 3 . 78 -6.51. 3 . 8 0 -8 .33 3.82 -36.44

t 53

I l Hff Al:t::. f IME At:f' . TIME ACC. TIME ACC . I 3.84 -26.68 3.86 -27.42 3.88 -29.83 3.90 -32.33 I

t 3.92 -4. 72 3.94 3,95 3.96 -50.74 3.98 53.25 4.00 --56 . 54 4.02 -60 .72 4.04 -29.48 4.06 -0.01 4.()EJ -11. 45 4.10 - 13.56 4.12 -29.51 4.14 -17.90

'

4. :1.6 -5. 79 4.18 -20 .86