World Housing Encyclopedia Report

Country: Syrian Arab Republic

Housing Type: Moment resisting frame designed for gravity loads only

Contributors:Adel AwadHwaija BassamIsreb Talal

Primary Reviewer:Ravi Sinha

Created on: 6/5/2002Last Modified: 7/5/2003

This encyclopedia contains information contributed by various earthquake engineering professionalsaround the world. All opinions, findings, conclusions, and recommendations expressed herein are those

of the various participants, and do not necessarily reflect the views of the Earthquake EngineeringResearch Institute, the International Association for Earthquake Engineering, the Engineering Information

Foundation, John A. Martin & Associates, Inc. or the participants' organizations.

Table of Contents

General Information............................................................................................1Architectural Features........................................................................................ 2Socio-Economic Issues...................................................................................... 3Structural Features............................................................................................. 5Evaluation of Seismic Performance and Seismic Vulnerability.......................... 9Earthquake Damage Patterns............................................................................ 11Building Materials and Construction Process..................................................... 12Construction Economics.....................................................................................14Insurance............................................................................................................15Seismic Strengthening Technologies................................................................. 16References......................................................................................................... 17Contributors........................................................................................................ 18Figures................................................................................................................19

1 General Information

1.1 CountrySyrian Arab Republic

1.3 Housing TypeMoment resisting frame designed for gravityloads only

1.4 SummaryThese buildings are found in the main cities ofSyria and represent modern constructionpractice followed in the last 50 years. The floorsystem is a two-way reinforced concrete slab,which spans between orthogonal sets of beamsthat transfer the load to the columns. The framesare designed to carry gravity loads only.

FIGURE 1: Typical Building

1.5 Typical Period of Practice for Buildings of This Construction TypeHow long has thisconstruction been practiced< 25 years< 50 years X< 75 years< 100 years< 200 years> 200 years

Is this construction still being practiced? Yes NoX

Additional Comments: Modern construction followed in the last 50 years.

1.6 Region(s) Where UsedThis type of construction exists in main cities of Syria: Damascus, Aleppo, Latakia, Homs, Hama, Deir-ezzor , Idleb , AL-Haskeh , Al-Raka , Al-Sweida , Dara , Tartus , Jableh , Qunitera etc.

1.7 Urban vs. Rural ConstructionWhere is this construction commonly found?In urban areas XIn rural areasIn suburban areasBoth in rural and urban areas

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2 Architectural Features

2.1 OpeningsArea of openings /walls surface area = 20% for inner walls and 40% for outer walls

2.2 SitingYes No

Is this type of construction typically found on flat terrain? XIs this type of construction typically found on sloped terrain? (hilly areas) XIs it typical for buildings of this type to have common walls with adjacentbuildings?

The typical separation distance between buildings is meters and more. meters

2.3 Building ConfigurationRectangular

2.4 Building FunctionWhat is the main function for buildings of this type?Single family houseMultiple housing units XMixed use (commercial ground floor, residential above)Other (explain below)

2.5 Means of EscapeUsually building hasn't additional exit besides the main.

2.6 Modification of BuildingsThere aren't a lot of modifications in this buildings yet.

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3 Socio-Economic Issues

3.1 Patterns of OccupancyOne family typically occupies one apartment.

3.2 Number of Housing Units in a Building12 units in each building.

Additional Comments: There are from 6 to 12 units in each building.

3.3 Average Number of Inhabitants in a BuildingHow many inhabitants reside in a typical building of thisconstruction type?

During the day / businesshours

During the evening / night

< 55 to 1010-20 X> 20 XOther

3.4 Number of Bathrooms or Latrines per Housing UnitNumber of Bathrooms: 1Number of Latrines: 0

Additional Comments: 1 to 2 bathrooms.

3.5 Economic Level of InhabitantsEconomic Status House Price/Annual Income

(Ratio)Very poor /Poor X 10000/2500Middle Class X 15000/6000Rich /

Additional Comments: GNP per capita, in 1997, was $1120 ; GDP per capita, in 1996, was $1288

3.6 Typical Sources of FinancingWhat is the typical source of financing for buildings of this type?Owner Financed XPersonal Savings XInformal Network: friends and relativesSmall lending institutions/microfinance institutionsCommercial banks / mortages XInvestment poolsCombination (explain)Government-owned housing XOther

3.7 OwnershipType of Ownership/OccupancyRent XOwn outright XOwn with Debt (mortgage or other) XUnits owned individually (condominium)Owned by group or poolLong-term lease XOther X

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Additional Comments: Ownership by heritage is also found.

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4 Structural Features

4.1 Lateral Load-Resisting SystemWe can assume that the frames (columns + beams) provide a partial strength and stiffness to controllateral displacements due to moderate earthquakes.

4.2 Gravity Load-Bearing StructureFrames (columns, beams) carry gravity loading.

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4.3 Type of Structural SystemMaterial Type of

Load-BearingStructure

# Subtypes

Masonry Stone masonrywalls

1 Rubble stone (field stone) in mud/lime mortar or withoutmortar (usually with timber roof)

2 Massive stone masonry (in lime or cement mortar)Earthen walls 3 Mud walls

4 Mud walls with horizontal wood elements5 Adobe block or brick walls6 Rammed earth/Pise construction

Unreinforced brickmasonry walls

7 Unreinforced brick masonry in mud or lime mortar8 Unreinforced brick masonry in mud or lime mortar with

vertical posts9 Unreinforced brick masonry in cement or lime mortar

(various floor/roof systems)Confined masonry 10 Confined brick/block masonry with concrete posts/tie

columns and beamsConcrete blockmasonry walls

11 Unreinforced in lime or cement mortar (various floor/roofsystems)

12 Reinforced in cement mortar (various floor/roof systems)13 Large concrete block walls with concrete floors and roofs

Concrete Moment resistingframe

14 Designed for gravity loads only (predating seismic codes i.e.no seismic features)

X

15 Designed with seismic features (various ages)16 Frame with unreinforced masonry infill walls17 Flat slab structure18 Precast frame structure19 Frame with concrete shear walls-dual system20 Precast prestressed frame with shear walls

Shear wall structure 21 Walls cast in-situ22 Precast wall panel structure

Steel Moment resistingframe

23 With brick masonry partitions24 With cast in-situ concrete walls25 With lightweight partitions

Braced frame 26 Concentric27 Eccentric

Timber Load-bearingtimber frame

28 Thatch29 Post and beam frame30 Walls with bamboo/reed mesh and post (wattle and daub)31 Wooden frame (with or without infill)32 Stud wall frame with plywood/gypsum board sheathing33 Wooden panel or log construction

Various Seismic protectionsystems

34 Building protected with base isolation devices or seismicdampers

Other 35

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4.4 Type of FoundationType Description

Shallow Foundation Wall or column embedded in soil, without footingRubble stone (fieldstone) isolated footingRubble stone (fieldstone) strip footingReinforced concrete isolated footing XReinforced concrete strip footingMat foundationNo foundation

Deep Foundation Reinforced concrete bearing pilesReinforced concrete skin friction pilesSteel bearing pilesWood pilesSteel skin friction pilesCast in place concrete piersCaissons

Other

4.5 Type of Floor/Roof SystemMaterial Description of floor/roof system Floor Roof

Masonry VaultedComposite masonry and concrete joist

StructuralConcrete

Solid slabs (cast in place or precast) X XCast in place waffle slabsCast in place flat slabsPrecast joist systemPrecast hollow core slabsPrecast beams with concrete toppingPost-tensioned slabs

Steel Composite steel deck with concrete slabTimber Rammed earth with ballast and concrete or plaster finishing

Wood planks or beams with ballast and concrete or plaster finishingThatched roof supported on wood purlinsWood single roofWood planks or beams that support clay tilesWood planks or beams that support slate, metal asbestos-cement or plasticcorrugated sheets or tilesWood plank, plywood or manufactured wood panels on joists supported bybeams or walls

Other

4.6 Typical Plan DimensionsLength: 20 - 20 metersWidth: 20 - 20 metersAdditional Comments: Length varies from 12 to 20 meters, width varies from 12 to 16 meters.

4.7 Typical Number of Stories3 - 5

4.8 Typical Story Height3 meters

Additional Comments: Story height ranges from 2.85 to 3.1 meters.

4.9 Typical Span3.0-5.5 meters

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4.10 Typical Wall DensityTotal wall area/plan area (for each floor) 10% to 15%

4.11 General Applicability of Answers to Questions in Section 4

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5 Evaluation of Seismic Performance and Seismic Vulnerability

5.1 Structural and Architectural Features: Seismic ResistanceStructural/ArchitecturalFeature

Statement True False N/A

Lateral load path The structure contains a complete load path for seismic force effects fromany horizontal direction that serves to transfer inertial forces form thebuilding to the foundation.

X

Buildingconfiguration

The building is regular with regards to both the plan and the elevation. X

Roof construction The roof diaphragm is considered to be rigid and it is expected that the roofstructure will maintain its integrity, i.e.. shape and form, during anearthquake of intensity expected in this area.

X

Floor construction The floor diaphragm(s) are considered to be rigid and it is expected that thefloor structure(s) will maintain its integrity, during an earthquake of intensityexpected in this area.

X

Foundationperformance

There is no evidence of excessive foundation movement (e.g. settlement)that would affect the integrity or performance of the structure in anearthquake.

X

Wall and framestructures-redundancy

The number of lines of walls or frames in each principal direction is greaterthan or equal to 2.

X

Wall proportions Height-to-thickness ratio of the shear walls at each floor level is: 1) Lessthan 25 (concrete walls); 2)Less than 30 (reinforced masonry walls); 3)Less than 13 (unreinforced masonry walls).

X

Foundation- wallconnection

Vertical load-bearing elements (columns, walls) are attached to thefoundations; concrete columns and walls are doweled into the foundation.

X

Wall-roofconnections

Exterior walls are anchored for out-of-plane seismic effects at eachdiaphragm level with metal anchors or straps.

X

Wall openings The total width of door and window openings in a wall is: 1) for brickmasonry construction in cement mortar: less than 1/2 of the distancebetween the adjacent cross walls; 2) for adobe masonry, stone masonryand brick masonry in mud mortar: less than 1/3 of the distance between theadjacent cross walls; 3) for precast concrete wall structures: less than 3/4 ofthe length of a perimeter wall.

X

Quality of buildingmaterials

Quality of building materials is considered to be adequate per requirementsof national codes and standards (an estimate).

X

Quality ofworkmanship

Quality of workmanship (based on visual inspection of few typical buildings)is considered to be good (per local construction standards).

X

Maintenance Buildings of this type are generally well maintained and there are no visiblesigns of deterioration of building elements (concrete, steel, timber).

X

Other

5.2 Seismic FeaturesStructural Element Seismic Deficiency Earthquake-Resilient Features Earthquake Damage PatternsWallFrame (columns,beams)

Weak connections between thesecondary and primary beams. Nospecial transverse reinforcement at thecritical region (joints).

Roof and floorsFoundations Reinforced concrete isolated footing

without compression/tension ties

Additional Comments: Poor quality of workmanship and materials. Development length not sufficient (£30f) in compression and tension regions.

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5.3 Seismic Vulnerability RatingVulnerability

High (Very PoorSeismicPerformance)

Medium Low (ExcellentSeismicPerformace)

A B C D E FSeismic

Vulnerability Class< 0 >

0 - probable value< - lower bound> - upper bound

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6 Earthquake Damage Patterns

6.1 Past Earthquakes Reported To Affect This ConstructionYear Earthquake Epicenter Richter magnitude(M) Maximum Intensity (Indicate

Scale e.g. MMI, MSK)1822 Aleppo/Al-jaziereh 7 (MMI) IX-X1822 Harem/Aleppo 6 (MMI) VIII1796 Lattakia 6 (MMI) VIII1759 Damascus 7.6 (MMI) X1759 Damascus/Lattakia 7.5 (MMI) X1719 Aleppo 5.5 (MMI) VII

Additional Comments: Data about the earthquakes, starting from 18th century up to date, were taken fromAmbraseys (1983). However, we have developed the estimate of the magnitude (M) and the maximumMMI intensity based on our findings and experience. Most of the buildings destroyed in the pastearthquakes were of adobe and stone masonry, particularly in the urban areas.

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7 Building Materials and Construction Process

7.1 Description of Building MaterialsStructural Element Building Material Characteristic Strength Mix Proportions/ Dimensions CommentsFoundations Concrete 1-3/18-25/1-2 1:2:4Frame Steel 360-420 Deformed barsRoof and floors Steel 360-420 Deformed bars

7.2 Does the builder typically live in this construction type, or is it more typicallybuilt by developers or for speculation?It is built by developers and sold to the people who live in this construction type.

7.3 Construction ProcessThe owner of the land will hire an architect and a structural engineer to design the building. They will usemodern equipment.

7.4 Design/Construction ExpertiseA structural engineer will have 5 years of education and more 5-10 years of experience. A constructionengineer may have 5 years of education and less experience than the structural engineer. The designermay visit the construction site, at request.

7.5 Building Codes and StandardsYes No

Is this construction type addressed by codes/standards? X

Title of the code or standard: Starting from 1997, the seismic design for buildings is mandatory as a law:Syrian code for earthquake resistant building (1995). Prior to 1997, seismic design was not applicable butthe normal Syrian building code is used from 1972.

7.6 Role of Engineers and ArchitectsYes, They have a role in the design, constriction and inspection during the construction phase (see 7.3and 7.4)

7.7 Building Permits and Development Control RulesYes No

Building permits are required XInformal construction XConstruction authorized per development control rules X

7.8 Phasing of ConstructionYes No

Construction takes place over time (incrementally) XBuilding originally designed for its final constructed size X

7.9 Building MaintenanceWho typically maintains buildings of this type?BuilderOwner(s) XRenter(s) XNo oneOther

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7.10 Process for Building Code EnforcementThe building design must follow the 1995 Syrian code. In case of damage arbitration process may takeplace at the court of justice.

7.11 Typical Problems Associated with this Type of ConstructionThe main problems are associated with the construction process e.g. mixing and transportation ofconcrete, and construction joints.

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8 Construction Economics

8.1 Unit Construction Cost (estimate)A unit construction may cost 100-200 USD/m² (USD =50 Syrian pound (SP), on market rate)

8.2 Labor Requirements (estimate)One floor per month.

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9 Insurance

9.1 Insurance IssuesYes No

Earthquake insurance for this construction type is typically available XInsurance premium discounts or higher coverages are available for seismicallystrengthened buildings or new buildings built to incorporate seismically resistantfeatures

X

9.2 If earthquake insurance is available, what does this insurance typicallycover/cost?Not applicable.

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10 Seismic Strengthening Technologies

10.1 Description of Seismic Strengthening ProvisionsType of intervention Structural Deficiency Description of seismic strengthening provision used

Additional Comments: Seismic strengthening has generally not been performed in Syria.

10.2 Has seismic strengthening described in the above table been performed indesign practice, and if so, to what extent?No.

10.3 Was the work done as a mitigation effort on an undamaged building, or asrepair following earthquake damage?

10.4 Was the construction inspected in the same manner as new construction?

10.5 Who performed the construction: a contractor, or owner/user? Was anarchitect or engineer involved?

10.6 What has been the performance of retrofitted buildings of this type insubsequent earthquakes?

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11 ReferencesCentral Bureau of Statistics (1999), " Statistical Abstract 1999" , Damascus, 1999.

Ambraseys, N. N. (1993) "Earthquake Damage in the Arabic Region", In : Assessment And Mitigation,UNESCO Publication , pp. 11-15.

United Nations Development Program (UNDP) (1999), " Urban Development Report 1999", OxfordUniversity Press, NY.

Paulay, T and Priestley, M.J.N. (1992), " Seismic Design of Reinforced Concrete and Masonry Buildings", John Wiley and Sons.

Syrian Engineers Order (1995), "Syrian Code for Earthquake Resistant Design and Construction ofBuildings".

Grünthal, G. et al. (1998), "European Macroseismic Scale 1998 , EMS-98", European SeismologicalCommission (ESC), Luxembourg.

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12 ContributorsName Adel Awad Hwaija Bassam Isreb TalalTitle Civil Engineer/Professor Civil Engineer Associate

ProfessorCivil Engineer

Affiliation University of Tishreen University of Tishreen University of TishreenAddress P.O.Box: 1385 P.O.Box: 1385City Latakia Latakia LatakiaZipcodeCountry Syrian Arab Republic Syrian Arab Republic Syrian Arab RepublicPhone 963-41-470745 963-41-422156 963-41-422156Fax 963-41-418504 963-41-418504Email tuniv-lat@net.sy tuniv-lat@net.sy tuniv-lat@net.syWebpage

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13 Figures

FIGURE 1: Typical Building

FIGURE 2: Key Load-Bearing Elements

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FIGURE 3A: Plan of a Typical Building

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FIGURE 3B: Plan of a Typical Building

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FIGURE 4A: Critical Structural Details

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FIGURE 4B: Critical Structural Details

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