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World Housing Encyclopedia Report
Country: Uzbekistan
Housing Type: Precast reinforced concrete frame panel system of seria IIS-04
Contributors:Shamil KhakimovBakhtiar Nurtaev
Primary Reviewer:Svetlana Brzev
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............................................................................ 12Building Materials and Construction Process..................................................... 13Construction Economics.....................................................................................15Insurance............................................................................................................16Seismic Strengthening Technologies................................................................. 17References......................................................................................................... 18Contributors........................................................................................................ 19Figures................................................................................................................20
1 General Information
1.1 CountryUzbekistan
1.3 Housing TypePrecast reinforced concrete frame panel systemof seria IIS-04
1.4 SummaryThis housing type is used for the construction ofresidential and public buildings in many citiesthroughout Uzbekistan -- including the capitalcity Tashkent -- which are located in zones withintensities between 7-9. Residential buildings ofthis type are generally 9 to 12 stories high,whereas public buildings of the sameconstruction are 1 to 4 stories high. All seismicload-resisting (and also nonstructural)components, e.g., foundations, columns, girders,slabs, staircases, wall panels, etc., aremanufactured in specialized plants.Subsequently, the materials are transported tothe building site. The positive features of thisconstruction type are 1) the ability tomanufacture all building materials in anindustrialized setting, and 2) the gain inefficiency because the same buildingcomponents may be used both for residentialand public buildings. The key drawback is thatthe welded joints cause seismic vulnerability,when the building is located in zones ofextremely high seismic loads. These joints haveshown extremely brittle behavior in earthquakes.Earthquake damage is mainly concentrated inthe column joints, or in the column-to-girderjoints. In some cases non-bearing walls andexterior wall panels have collapsed.
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: This traditional construction practice has been followed for over 35 years. Theframe panel seria IIS-04 was first used in 1973.
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1.6 Region(s) Where UsedTashkent and other cities of Uzbekistan and Central Asia. In Tashkent, this housing type accounts forover 18% of the residential building stock and for over 25% of the public building stock.
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 OpeningsIn this housing type, the main load-bearing elements are the columns, beams and joints (a framestructure). Therefore, seismic vulnerability does not depend on the number and size of the openings. Thesize of the windows and doors ranges from 2.25 m to 4.5 m.
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 30 meters
2.3 Building ConfigurationUsually a rectangular plan.
2.4 Building FunctionWhat is the main function for buildings of this type?Single family houseMultiple housing unitsMixed use (commercial ground floor, residential above) XOther (explain below)
2.5 Means of EscapeThe means of escape depends upon the number of apartments on the floor. If a building has "point block"planning (2-4 apartments without a corridor at each floor level), there is typically one staircase and oneexit.
2.6 Modification of BuildingsMinor modifications of interior partition walls may be done by the owners.
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3 Socio-Economic Issues
3.1 Patterns of OccupancyIt depends on the size of the multi-story building. Typically, over 60 families live in a 12-story building.
3.2 Number of Housing Units in a Building60 units in each building.
Additional Comments: Usually more than 60 units in a 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> 20 XOther X
3.4 Number of Bathrooms or Latrines per Housing UnitNumber of Bathrooms: 1Number of Latrines: 0
3.5 Economic Level of InhabitantsEconomic Status House Price/Annual Income
(Ratio)Very poor /Poor X /Middle Class X 5000/720Rich /
3.6 Typical Sources of FinancingWhat is the typical source of financing for buildings of this type?Owner FinancedPersonal SavingsInformal 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)Units owned individually (condominium)Owned by group or poolLong-term leaseOther
Additional Comments: Almost 90% of the buildings are privately owned and 10% are rented from the localgovernment.
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4 Structural Features
4.1 Lateral Load-Resisting SystemThe lateral load-resisting system is reinforced concrete frame, which consists of precast columns andbeams and cast in-situ or precast concrete shear walls. Precast frame elements are joined together in thespace frame structure. Shear walls may be made of precast panels or cast in-situ elevator cores in thetaller buildings of this type (e.g., 12-story buildings). In medium-rise buildings of this type (e.g., 4-5stories), the entire lateral load-resisting system consists of a RC frame only (i.e., shear walls are notpresent). Precast floor panels are joined in a rigid diaphragm for the distribution of lateral forces.
4.2 Gravity Load-Bearing StructureThe gravity load-bearing structure consists of reinforced concrete frame, including precast columns andbeams and precast floor 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 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)
15 Designed with seismic features (various ages)16 Frame with unreinforced masonry infill walls17 Flat slab structure18 Precast frame structure X19 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 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
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 slabs X X
4.6 Typical Plan DimensionsLength: 24 - 24 metersWidth: 24 - 24 metersAdditional Comments: Typical plan dimensions: 18x18m, 12x36m, 15x24m
4.7 Typical Number of Stories9 - 12
4.8 Typical Story Height3 meters
4.9 Typical Span6 meters
Additional Comments: The typical span may be either 6 or 3 meters.
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4.10 Typical Wall Density5%
4.11 General Applicability of Answers to Questions in Section 4This contribution describes a generic building type and is not based on a case study of a particularbuilding.
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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
Additional Comments: Precast floor panels are constructed with special grooves and steel dowelsprojected on all four sides for achieving the cast in-situ joint. This type of floor structure subjected tolateral loads was tested in the lab. The roof diaphragm is considered to be rigid provided that the qualityof construction is adequate.
5.2 Seismic Features
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Structural Element Seismic Deficiency Earthquake-Resilient Features Earthquake Damage PatternsPartition walls(cladding)
Exterior and interior partition walls arenon-load-bearing (i.e., they carry theirown weight only).
Due to poor quality of wall-column andwall-beam joints, the walls mayexperience serious damage in anearthquake.
Frame (columns,beams)
The most vulnerable parts of a frameare beam-column joints; these weldedjoints are located in the area ofextremely high loads. As a result of thewelding, steel reinforcement bars mayhave loose ductility. Also, the concretepoured in these joints is often poorlyvibrated.
Damage to beam-column joints
Roof and floors The joints between the precast slabs(grouted in-situ) are sometimes notproperly filled with grout and may losetheir strength in an earthquake.
Damage of horizontal panel joints andthe subsequent loss of rigid diaphragmbehavior
Wall panels,(verticaldiaphragms)
The assembled reinforced concretediaphragms are inadequately welded tothe columns. Vertical bars discontinuedduring the site installation; Due to poorquality of construction, the diaphragmstrength may be reduced by 50%.
Failure of precast diaphragm-to-frameconnections.
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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)1988 Spitak (Armenia) 7.5 IX-X (MSK)1984 Gazli 7.2 IX (MSK)
Additional Comments: Buildings of this type were damaged during the 1988 Spitak earthquake, asillustrated in Figures 6A and 6B.
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7 Building Materials and Construction Process
7.1 Description of Building MaterialsStructural Element Building Material Characteristic Strength Mix Proportions/ Dimensions CommentsPartition Walls Reinforced
concreteThese walls are not lateralload-resisting elements Mix -1: 1.5: 2.4: 0.45 Dimensions6000 X 1500 X 250 (mm)
Foundations Reinforcedconcrete
10-15 MPa (cubecompressive strength)
Mix- 1: 1,4: 2: 0,49Dimensions: 1400 X 1400 X900 (mm)
Wall panels(verticaldiaphragms)
Reinforcedconcrete
30 MPa (cube compressivestrength)
Mix- 1: 1.75: 3.21: 0.51Dimensions 5600 X 140 X3280 (mm)
Roof and floors Reinforcedconcrete
30 MPa (cube compressivestrength)
Mix- 1: 1.75: 3.24: 0.44Dimensions : 6000 X 220 X1600 (mm)
Column Reinforcedconcrete
40 MPa (cube compressivestrength)
1: 2: 3: 0.5 Cross sectionaldimensions: 400 X 400 (mm)X height (3300 -13500 mm)
Girder Reinforcedconcrete
40 MPa (cube compressivestrength)
Mix- 1: 1.4: 2.8: 0.49Cross-sectional dimensions:420 X 480 (mm)
7.2 Does the builder typically live in this construction type, or is it more typicallybuilt by developers or for speculation?A builder may live in this construction type, and his children may attend the schools housed in buildings ofthis type. Typically, frame panel buildings are constructed by order of the municipality.
7.3 Construction ProcessBased on the order of the government, a design agency develops a seria of industrialized constructionelements. Based on the information provided by the design agency, a concrete plant prepares a set ofmetal forms for the columns, girders, diaphragms, slabs, wall panels, staircases, etc., corresponding tothe requirements of a seria. Based on the order of a municipality or other clients, design firms developdesigns of individual buildings or typical (standardized) building designs. A concrete plant manufacturesand delivers all required building elements to the construction site. A construction company erects thebuilding at the construction site. The main pieces of equipment used for the construction are a towercrane, welding equipment, and concrete mixers.
7.4 Design/Construction ExpertiseAll designs are reviewed by the State Expert Bureau of the State Committee on Architecture andConstruction (SCAC); the revisions are incorporated in the final design (if required). Once the review iscompleted, the designs are forwarded to the concrete plants and the construction company. The concretestrength is evaluated in the laboratory in the concrete plant, and the reinforcement schedule is checkedand compared with the design documents. Periodically (once in six months), the laboratory data areexamined by a representative of the State Architecture Construction Control Department (SACC) ofSCAC. SCAC also monitors the construction quality at the site. In addition to this, a representative of thedesign agency or firm also performs a site inspection. The builders should take into account thedesigner's comments made during the site inspection. Once the construction is complete, a special stateexpert committee needs to approve the building and to issue the building permit.
7.5 Building Codes and StandardsYes No
Is this construction type addressed by codes/standards? X
Title of the code or standard: The construction is carried out based upon the catalogs of frame panel seriaIIS-04 (developed in 1973), and upon the National Building Code of Uzbekistan: "Construction in
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Earthquake-prone Areas" (KMK.2.01.03-96).National building code, material codes and seismic codes/standards: National Building Code, MaterialCodes and Seismic Codes/Standards; National Building Code of Uzbekistan: Construction inEarthquake-prone Areas (KMK.2.01.03-96).When was the most recent code/standard addressing this construction type issued? 1996
7.6 Role of Engineers and ArchitectsUse and selection of the typical, standard production of seria IIS-04 depend upon load conditions.Engineers and architects cannot change any construction details (joints, connections) in the existingseria, which is approved by the government. Only the agency that has developed the seria is able tochange the details.
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
7.10 Process for Building Code EnforcementDesign of buildings using the seria IIS-04 is carried out in accordance with the National Building Code ofUzbekistan: Construction in Earthquake-prone Areas.
7.11 Typical Problems Associated with this Type of ConstructionBuilders often have difficulty following the requirements for welding the joints between columns, girdersand diaphragms.
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8 Construction Economics
8.1 Unit Construction Cost (estimate)33000 sum/m² (110 US$/m²)
8.2 Labor Requirements (estimate)A 12-story residential building with 48 housing units and with plan dimensions 18x18m may be erected by10 workers in 10 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?Approximately 30% of the construction cost.
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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)
Beam-column joints Reinforcing of joints with steel platesFrame (column) Installation of additional (external) steel ties (straps)
Additional Comments: Seismic strengthening of a building in Tashkent is illustrated in Figures 7A and 7B.
10.2 Has seismic strengthening described in the above table been performed indesign practice, and if so, to what extent?Yes. Seismic strengthening was performed on some buildings in Tashkent.
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 ReferencesNational Building Code of Uzbekistan, "Construction in Earthquake-prone Areas," (KMK 2.01.03-96).
Concrete and Reinforced Concrete - Design Codes and Standards
Construction Catalog: seria IIS-04.16
Klyachko M. A., Earthquakes and Us. Intergraf, Saint Peterburg, Russia, 1999 (in Russian).
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12 ContributorsName Shamil Khakimov Bakhtiar NurtaevTitle Head of the Department Deputy DirectorAffiliation Institute of Typical and Experimental
Design AO UzLITTIInstitute of Geology and Geophysics
Address Nyazova 17 Khodjibaeva 49City Tashkent TashkentZipcode 700095 700041Country Uzbekistan UzbekistanPhone 99871 2 460703 99871 1626816Fax 99871 1626381Email [email protected]
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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 3: Plan of a Typical Building
FIGURE 4: Critical Structural Details
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FIGURE 5: An Illustration of Key Seismic Features and/or Deficiencies
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FIGURE 6A: Building damage in Leninakan (1988 Spitak, Armenia earthquake)
FIGURE 6B: Building damage in Leninakan (1988 Spitak, Armenia earthquake)
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FIGURE 6C: Building damage (1988 Spitak, Armenia earthquake)
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FIGURE 6D: Building damage (1988 Spitak, Armenia earthquake) Source: Klyachko 1999
FIGURE 6E: Building damage (1994 Shikotansk, Russia earthquake) Source: Klyachko 1999
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FIGURE 6F: Building damage (1994 Shikotansk, Russia earthquake) Source: Klyachko 1999
FIGURE 7A: Illustration of Seismic Strengthening Techniques
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FIGURE 7B: Illustration of Seismic Strengthening Techniques
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