World Housing Encyclopedia Report

Country: Kyrgyzstan

Housing Type: Single-family brick masonry house

Contributors:Ulugbek T. BegalievSvetlana Uranova

Primary Reviewer:Ravi Sinha

Created on: 6/5/2002Last Modified: 7/2/2003

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........................................................................................ 3Socio-Economic Issues...................................................................................... 4Structural 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 CountryKyrgyzstan

1.3 Housing TypeSingle-family brick masonry house

1.4 SummaryThis housing type represents a very popularsingle-family housing construction practicefollowed in Kyrgyzstan in the recent past.Approximately 80% buildings of this type, mostlythose constructed after 1990, do not comply withthe Building Code requirements. These arelow-rise (1- to 2-story high) buildings with acomplex plan and wall layout. The mainload-bearing system consists of brick masonrywalls in cement mortar partially confined withreinforced concrete posts and beams; columnsare provided only at some wall corners andintersections. Rigid brick masonry walls havelow load-carrying capacity. Wall thickness iseither 380 mm or 510 mm. SNiP (Building Code)includes provisions for the horizontal wallreinforcement (welded wire mesh at the wallcorners) and the provision of reinforced concretecolumns at the wall corners. The floor systemconsists of precast reinforced concretehollow-core slabs with typical slab paneldimensions of 5.86 m length X 1.2 m width.Reinforced concrete bond beam (belt) isconstructed at the building perimeter at the floorlevel to provide the confinement and diaphragmaction for seismic load effects. Complex buildinggeometry and irregular wall distribution results inthe significant torsional effects duringearthquakes due to the eccentricity between thecentre of mass and centre of stiffness. Thesebuildings are located in the regions of highseismic hazard, which had experiencedearthquakes of intensity VIII, IX or higher (perthe MSK scale) in the past. This type ofconstruction is expected to demonstrate poorseismic performance, due to the poor quality ofmasonry walls and complex layout resulting intorsional effects.

FIGURE 1: Typical Building

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

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< 200 years> 200 years

Is this construction still being practiced? Yes NoX

1.6 Region(s) Where UsedThis building type is used throughout the Kyrgyzstan.

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

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2 Architectural Features

2.1 OpeningsIt is impossible to indicate the typical size of openings since it depends on the architectural requirements.Size of windows is around 1.2 m X 1.5 m and doors size is approximately 0.9 m X 1.9 m. Window anddoor areas constitute 10 to 15% of the overall wall surface area.

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?

X

The typical separation distance between buildings is 10 meters

2.3 Building ConfigurationBuilding plan for this housing type usually has complex plan and geometry.

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

2.5 Means of EscapeThe building has only a single means of escape.

2.6 Modification of BuildingsUsually buildings of this type are of recent construction, and no modifications have been observed so far.However, some buildings have been modified by providing additional doors and windows, by expandingthe building size (by adding new rooms) or by moving the walls.

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3 Socio-Economic Issues

3.1 Patterns of OccupancyOne family typically occupies one house

3.2 Number of Housing Units in a Building1 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

< 5 X5 to 10 X10-20> 20Other

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

Additional Comments: In some cases a building has 2 bathrooms.

3.5 Economic Level of InhabitantsEconomic Status House Price/Annual Income

(Ratio)Very poor /Poor /Middle Class X /Rich X /

Additional Comments: House ratio to annual income is not available.

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 / mortagesInvestment poolsCombination (explain)Government-owned housingOther

3.7 OwnershipType of Ownership/OccupancyRentOwn outright XOwn with Debt (mortgage or other)Units owned individually (condominium)Owned by group or poolLong-term leaseOther

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4 Structural Features

4.1 Lateral Load-Resisting SystemThe main lateral load-resisting system generally consists of brick masonry walls in cement mortar andreinforced concrete posts and beams provided at some locations. According to SNiP (Building Code) it isrequired to provide columns at the wall ends; column reinforcement is illustrated in Figure 4B. SNiPrequirements also include the provision of horizontal reinforcement (wire mesh) in mortar bedding joints ateach 7th layer (see Figure 4C). Rigid brick masonry walls have low load-carrying capacity. Poor quality ofbrick masonry results in low earthquake resistance of the walls even when reinforced with welded wiremesh and steel reinforcement bars. Wall thickness is either 380 mm or 510 mm. The floor systemconsists of precast reinforced concrete hollow-core slabs with typical slab panel dimensions of 5.86mlength X 1.2m width (see Figure 2). Reinforced concrete bond beam (belt) is constructed at the buildingperimeter at the floor level to provide the confinement and diaphragm action for seismic load effects; beltreinforcement details are presented in Figure 4A. Roof structures are made of wood or steel.

4.2 Gravity Load-Bearing StructureGravity load-bearing structure consists of brick masonry walls, few reinforced concrete columns andbeams, and floor concrete panels.

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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 beamsX

Concrete 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)

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 footingReinforced concrete strip footing XMat foundationNo foundation

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

Other

Additional Comments: Many buildings have precast concrete strip footing made up of concrete blocks.

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)Cast 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

StructuralConcrete

Precast hollow core concrete slabs X X

Additional Comments: Precast hollow core slab system is most commonly used.

4.6 Typical Plan DimensionsLength: 15 - 15 metersWidth: 15 - 15 meters

4.7 Typical Number of Stories2

4.8 Typical Story Height3 meters

4.9 Typical Span6 meters

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4.10 Typical Wall Density0.1% - 0.15%Total wall density is 10% - 15% in each direction.

4.11 General Applicability of Answers to Questions in Section 4This is a description of a generic structural type. Variation in wall density of up to 20% as compared to theanswer given in Section 4.10 has been observed.

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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 PatternsWall - Poor quality of brick masonry; -

Different wall rigidity; - The complexbuilding geometry, including thenonsymmetrical wall layout, results insignificant torsional effects duringearthquakes due to the eccentricitybetween the centre of mass and centreof stiffness.

Diagonal shear cracks in the wall,cracks at the wall corners,partial/complete destruction of the wall.

Frame (columns,beams)Roof and floors

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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)1992 Suusamir 7.4 VII

Additional Comments: Maximum intensity of the Suusamir earthquake was IX, however buildings of thistype were located in the regions with intensity 6-7 on the MSK scale. Buildings of this type hadexperienced the following wall damage patterns: diagonal "X" cracks in the piers, cracks at the wallcorners, and partial destruction of the walls.

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7 Building Materials and Construction Process

7.1 Description of Building MaterialsStructural Element Building Material Characteristic Strength Mix Proportions/ Dimensions CommentsWalls Brick masonry Tension resistance of mortar

less 6.0 MPaVariable, from 1:8 to 1:20cement/sand ratio

Brick masonry units- dimensions 250 X120 X 70 mm

Foundations Concrete 5 MPa (cube compressivestrength)

various

Frame Concrete 20 MPa (cube compressivestrength) 390 MPa (steel yieldstress)

variable Steel - ElasticityModulus (200,000MPa)

Roof and floors Concrete 30-35 MPa (cubecompressive strength) 390MPa (steel yield stress)

variable Steel - ElasticityModulus (200,000MPa)

7.2 Does the builder typically live in this construction type, or is it more typicallybuilt by developers or for speculation?These constructions are built by developers and sold in the market.

7.3 Construction ProcessThis building type may be erected by builders or by owners. Usually only mobile crane is used for theerection and construction process.

7.4 Design/Construction ExpertiseThis building type is not designed or constructed with the required expertise.

7.5 Building Codes and StandardsYes No

Is this construction type addressed by codes/standards? X

Title of the code or standard: Some of buildings correspond to SNiP II-7-81 Design Code: Building inSeismic Regions.Year the first code/standard addressing this type of construction issued: 1981National building code, material codes and seismic codes/standards: SNiP II-7-81 : Building in SeismicRegions. Design Code.When was the most recent code/standard addressing this construction type issued? 1981

7.6 Role of Engineers and ArchitectsUsually manager of construction works as the engineer. Engineers play a very limited role in theconstruction of buildings of this type.

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 Maintenance

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Who typically maintains buildings of this type?BuilderOwner(s) XRenter(s)No oneOther

7.10 Process for Building Code EnforcementN/A

7.11 Typical Problems Associated with this Type of ConstructionThe construction quality is generally very poor, and the structural design has flows. This type ofconstruction is expected to display poor behavior during earthquakes.

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8 Construction Economics

8.1 Unit Construction Cost (estimate)For load-bearing structures about 150 US$/m².

8.2 Labor Requirements (estimate)The construction of a single-family house can be completed in a period of 10-12 months.

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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?N/A

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10 Seismic Strengthening Technologies

10.1 Description of Seismic Strengthening ProvisionsType of intervention Structural Deficiency Description of seismic strengthening provision usedRetrofit(Strengthening)

- Poor seismic resistance of walls; -Nonsymmetrical location of walls withdifferent rigidity

- Installation of new reinforced concrete overlays tied to the existingwalls - Installation of new shear walls

Additional Comments: Seismic strengthening provisions presented in the above table arerecommendations of the authors of this contribution.

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?N/A

10.4 Was the construction inspected in the same manner as new construction?N/A

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

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

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11 ReferencesSeismic Hazard and Buildings Vulnerability in Post-Soviet Central Asia Republics. Edited by Stephanie A.King, Vitaly I. Khalturin and Brian E. Tucker. Kluwer Academic Publishers, P.O. Box 17, 3300 AADordrecht, The Netherlands. (Proceeding of the NATO Advanced Research Workshop on EarthquakeRisk Management Strategies for Post-Soviet Central Asian Republics. Almaty, Kazakhstan, 22-25October 1996)

Building and Construction Design in Seismic Regions. Handbook. Uranova S.K., ImanbekovS.T#KyrgyzNIIPStroitelstva, Building Ministry Kyrgyz Republic.Bishkek.1996.

SNiP II-7-81* Building in seismic regions. (Building Code). Moscow, 1981.

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12 ContributorsName Ulugbek T. Begaliev Svetlana UranovaTitle Head of Department EngineerAffiliation KNIIPCAddress Vost Prom ZoneCholponatisky 2 107-1222 Harwood StreetCity Bishkek Vancouver, BCZipcode 720571 V6E 152Country Kyrgyzstan CanadaPhone 996-3312-237564 604-696-0563FaxEmail utbegaliev@yahoo.com uransv@yahoo.comWebpage

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13 Figures

FIGURE 1: Typical Building

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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 the Second Floor for a Typical Building shown in Figure 3

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FIGURE 4A: Critical Structural Details - Wall-Floor Connection Showing Reinforced Concrete BondBeam (belt) Reinforcement

FIGURE 4B: Horizontal Wall Section Showing Reinforced Concrete Column Reinforcement

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FIGURE 4C: Horizontal Wall Section Showing Corner Reinforcement

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