Description

The World Housing Encyclopedia (WHE) Report Database contains 130 reports on housing construction types in 43 seismically active countries. Each housing report is a detailed description of a housing type in a particular country. The description is prepared from a number of standard closed-ended questions and some narrative that have been provided by report authors. Each report has five major categories including architectural and structural features; Building Materials and Construction Process; Socio-economic Issues; Past Performance In Earthquakes, Seismic Features and Vulnerability; and Retrofit. All of the housing reports in this database have been contributed by volunteers. If you are interested in writing a housing report please contact the WHE Editorial Board.

About

The World Housing Encyclopedia (WHE) is a collection of resources related to housing construction practices in the seismically active areas of the world. The mission is to share experiences with different construction types and encourage the use of earthquake-resistant technologies worldwide. The technical activities of the WHE are steered by an international team of 22 professionals specializing in different aspects of seismic safety of buildings and structures. They bring relevant experience from 16 seismically active countries across the world. For more information about the World Housing Encyclopedia, visit http://www.world-housing.net/.

General Information

 

Report #:34
Building Type: Buildings with hollow clay tile load-bearing walls and precast concrete floor slabs
Country: Kyrgyzstan
Author(s): Ulugbek T. Begaliev
Svetlana Uranova
Last Updated:
Regions Where Found: Buildings of this construction type can be found in large parts of Kyrgyzstan: Most of them are located in urban areas.
Summary:

Buildings of this type are characterized with load-bearing masonry walls ...

Length of time practiced: 51-75 years
Still Practiced: No
In practice as of:
Building Occupancy: Residential, 50+ units
Typical number of stories: 4
Terrain-Flat: Typically
Terrain-Sloped: 3
Comments: Usually there are 32-64 units in each building.


 

Features

 

 

Plan Shape Rectangular, solid
Additional comments on plan shape Typical shape of a building plan for this housing type is rectangular.
Typical plan length (meters) 60
Typical plan width (meters) 12
Typical story height (meters) 2.7
Type of Structural System Other
Additional comments on structural system Lateral load-resisting system: Lateral load-resisting system consists of exterior walls of small-size clay block masonry and interior brick masonry walls. The exterior walls are made of hollow clay masonry tiles (blocks). The block dimensions are: 138 mm (height)x120mmx250mm. The blocks have oval hollow cores (90mmx16mm). The area of the cores accounts for 25-33 % of the block area. Due to the large area of hollow cores, masonry is characterized with rather low tensile resistance. Usually mortar is of a poor quality. In some cases, exterior walls consist of two wythes; the exterior wythe is made of hollow clay tiles whereas the interior wythe is made of solid bricks (dimensions 250 mm thickness x 120mm x 70 mm). Floor system consists of precast reinforced concrete hollow core slabs. Dimensions of slab panels are 5.86m length x1.2m width. The panels are combined in a uniform diaphragm by means of reinforced concrete belt (cast in-situ reinforced concrete beam). Windows and door lintels are of precast concrete construction. Gravity load-bearing system: Gravity load-bearing structure consists of load-bearing masonry walls and concrete floor slabs.
Gravity load-bearing & lateral load-resisting systems Masonry: Clay brick/block masonry walls: Unreinforced brick masonry in cement mortar with reinforced concrete floor/roof slabs
Typical wall densities in direction 1 5-10%
Typical wall densities in direction 2 5-10%
Additional comments on typical wall densities
Wall Openings Typical window size is 1.2m x 1.2m. Typical door size is 0.9m(width) x 1.9m(height). The overall window and door area accounts for 10 to12% of the overall wall surface area.
Is it typical for buildings of this type to have common walls with adjacent buildings? Yes
Modifications of buildings There are lot of modifications at the ground floor level in buildings of this type. Typical modifications include installation of new door and windows openings, complete/partial removal of existing walls, and horizontal extension (addition of rooms).
Type of Foundation Shallow Foundation: Reinforced concrete strip footing
Additional comments on foundation
Type of Floor System Other floor system
Additional comments on floor system Structural concrete: Precast hollow core concrete slabs
Type of Roof System Roof system, other
Additional comments on roof system Structural concrete: Precast hollow core concrete slabs
Additional comments section 2 Typical separation distance between buildings: 10 meters or more

 

Building Materials and Construction Process

 

 

Description of Building Materials


Structural Element Building Material (s)Comment (s)
Wall/Frame Wall: MasonryWall: Characteristic Strength- Tension resistance of mortar: less than 60 MPa Mix Proportion/Dimensions- mortar mix 1:12 (cement/sand)and less (different, depending on mix materials)
Foundations ConcreteCharacteristic Strength: 5-7 MPa (cube compressive strength) Mix Proportion/Dimensions: 1:3:6 (different, depending on mix materials)
Floors Reinforced Concrete Characteristic Strength: 30-35 MPa (cube compressive strength) steel: flow limit 390 MPa, Elasticity Modulus 200MPa Mix Proportion/Dimensions: 1:1,7:3,2 (different depending on type of mix materials)
Roof Reinforced Concrete Characteristic Strength: 30-35 MPa (cube compressive strength) steel: flow limit 390 MPa, Elasticity Modulus 200MPa Mix Proportion/Dimensions: 1:1,7:3,2 (different depending on type of mix materials)
Other

Design Process


Who is involved with the design process? EngineerArchitect
Roles of those involved in the design process Design institutes develop design documentation.
Expertise of those involved in the design process Expertise is necessary for the design and the different stages of construction according to the laws of the Kyrgyz Republic.

Construction Process


Who typically builds this construction type? Contractor
Roles of those involved in the building process These buildings are constructed by contractors; special construction companies perform construction.
Expertise of those involved in building process Engineers play a leading role in each stage of construction.
Construction process and phasing Precast elements and bricks are made at the plant. Main equipment for construction is: crane, welding equipment and concrete mixers. This building is typically constructed incrementally and is not designed for its final constructed size.
Construction issues The problems are associated with the use of hollow clay tiles (blocks) for load-bearing walls, large span for cross walls, and poor quality of construction.

Building Codes and Standards


Is this construction type address by codes/standards? Yes
Applicable codes or standards SN-8-57.Building norm and guiding principles in seismic regions, SNiP II-A.12-62 Building in seismic regions:Design codes. The first code/standard addressing this type of construction was issued 1957; the most recent code/standard addressing this construction was issued 1981. Applicable national building code, material codes and seismic code/standards: SNiP II-7-81. Building in Seismic Regions.Design code
Process for building code enforcement Building permit will be given if the design documents have been approved by State Experts. State Experts check the compliance of design documents with pertinent Building Codes. According to building bylaws, the building cannot be used without the formal approval of a special committee. The committee grants approval (permit) if design documents are complete and the construction has been carried out in compliance with Building Codes.

Building Permits and Development Control Rules


Are building permits required? Yes
Is this typically informal construction? No
Is this construction typically authorized as per development control rules? Yes
Additional comments on building permits and development control rules

Building Maintenance and Condition


Typical problems associated with this type of construction
Who typically maintains buildings of this type? BuilderRenter(s)
Additional comments on maintenance and building condition

Construction Economics


Unit construction cost For load-bearing structure only: about $ 150/sq.m.
Labor requirements It would take 12 to 24 months for a team of 15 workers to build the structure only.
Additional comments section 3

 

Socio-Economic Issues

 

 

Patterns of occupancy Each floor in the building consists of 2 to 4 housing units. One family occupies one housing unit. Depending on the number of building units and stories, 32 to 64 families occupy one building.
Number of inhabitants in a typical building of this construction type during the day >20
Number of inhabitants in a typical building of this construction type during the evening/night >20
Additional comments on number of inhabitants
Economic level of inhabitants Low-income class (poor)Middle-income class
Additional comments on economic level of inhabitants 80% poor, 20% middle class
Typical Source of Financing Personal savingsGovernment-owned housing
Additional comments on financing Before 1990 all construction typically had a government source of financing. Now, all existing apartment buildings are private.
Type of Ownership Own outrightUnits owned individually (condominium)
Additional comments on ownership
Is earthquake insurance for this construction type typically available? No
What does earthquake insurance typically cover/cost
Are premium discounts or higher coverages available for seismically strengthened buildings or new buildings built to incorporate seismically resistant features? No
Additional comments on premium discounts
Additional comments section 4

 

Earthquakes

 

 

Past Earthquakes in the country which affected buildings of this type


YearEarthquake Epicenter Richter Magnitude Maximum Intensity
1992Suusamir (Kyrgyz Republic)
1986Kairakum (Kyrgyz Republic, Tadjikistan)
1988Spitak, Armenia
7.47 (MSK)
6.87 (MSK)
710 (MSK)

Past Earthquakes


Damage patterns observed in past earthquakes for this construction type Diagonal cracks in wall, cracks at the wall corners, out-of-plane collapse walls, partial or complete collapse of buildings.
Additional comments on earthquake damage patterns Overall damage patterns observed in past earthquakes for this type of construction included damage to walls: inclined and diagonal cracks in the piers, destruction of building corners, partial collapse of walls.

Structural and Architectural Features for Seismic Resistance


The main reference publication used in developing the statements used in this table is FEMA 310 “Handbook for the Seismic Evaluation of Buildings-A Pre-standard”, Federal Emergency Management Agency, Washington, D.C., 1998.

The total width of door and window openings in a wall is: For brick masonry construction in cement mortar : less than ½ of the distance between the adjacent cross walls; For adobe masonry, stone masonry and brick masonry in mud mortar: less than 1/3 of the distance between the adjacent cross walls; For precast concrete wall structures: less than 3/4 of the length of a perimeter wall.
Structural/Architectural Feature Statement Seismic Resistance
Lateral load pathThe structure contains a complete load path for seismic force effects from any horizontal direction that serves to transfer inertial forces from the building to the foundation.FALSE
Building Configuration-VerticalThe building is regular with regards to the elevation. (Specify in 5.4.1)TRUE
Building Configuration-HorizontalThe building is regular with regards to the plan. (Specify in 5.4.2)TRUE
Roof ConstructionThe roof diaphragm is considered to be rigid and it is expected that the roof structure will maintain its integrity, i.e. shape and form, during an earthquake of intensity expected in this area.TRUE
Floor ConstructionThe floor diaphragm(s) are considered to be rigid and it is expected that the floor structure(s) will maintain its integrity during an earthquake of intensity expected in this area.TRUE
Foundation PerformanceThere is no evidence of excessive foundation movement (e.g. settlement) that would affect the integrity or performance of the structure in an earthquake. TRUE
Wall and Frame Structures-RedundancyThe number of lines of walls or frames in each principal direction is greater than or equal to 2.TRUE
Wall ProportionsHeight-to-thickness ratio of the shear walls at each floor level is: Less than 25 (concrete walls); Less than 30 (reinforced masonry walls); Less than 13 (unreinforced masonry walls);TRUE
Foundation-Wall ConnectionVertical load-bearing elements (columns, walls) are attached to the foundations; concrete columns and walls are doweled into the foundation.FALSE
Wall-Roof ConnectionsExterior walls are anchored for out-of-plane seismic effects at each diaphragm level with metal anchors or straps. TRUE
Wall OpeningsTRUE
Quality of Building MaterialsQuality of building materials is considered to be adequate per the requirements of national codes and standards (an estimate). FALSE
Quality of WorkmanshipQuality of workmanship (based on visual inspection of a few typical buildings) is considered to be good (per local construction standards).FALSE
MaintenanceBuildings of this type are generally well maintained and there are no visible signs of deterioration of building elements (concrete, steel, timber).FALSE

Additional comments on structural and architectural features for seismic resistance
Vertical irregularities typically found in this construction type Other
Horizontal irregularities typically found in this construction type Other
Seismic deficiency in walls #NAME?
Earthquake-resilient features in walls
Seismic deficiency in frames
Earthquake-resilient features in frame
Seismic deficiency in roof and floors
Earthquake resilient features in roof and floors
Seismic deficiency in foundation
Earthquake-resilient features in foundation

Seismic Vulnerability Rating


For information about how seismic vulnerability ratings were selected see the Seismic Vulnerability Guidelines

High vulnerabilty Medium vulnerabilityLow vulnerability
ABCDEF
Seismic vulnerability class |- o -|

Additional comments section 5

Retrofit Information

 

 

Description of Seismic Strengthening Provisions


Structural Deficiency Seismic Strengthening

Additional comments on seismic strengthening provisions
Has seismic strengthening described in the above table been performed?
Was the work done as a mitigation effort on an undamaged building or as a repair following earthquake damages?
Was the construction inspected in the same manner as new construction?
Who performed the construction: a contractor or owner/user? Was an architect or engineer involved?
What has been the performance of retrofitted buildings of this type in subsequent earthquakes?
Additional comments section 6

 

References

Seismic 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 AA Dordrecht, The Netherlands. (Proceeding of the NATO Advanced Research Workshop on Earthquake Risk Management Strategies for Post-Soviet Central Asian Republics. Almaty, Kazakhstan, 22-25 October 1996).


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


SNiP II-7-81* Building in seismic regions. (Building Code). Moscow, 1981. Klyachko M. A. Earthquakes and Us. Intergraf, Saint Peterburg, Russia, 1999 (in Russian).


Authors



Name Title Affiliation Location Email
Ulugbek T. Begaliev Head of Department KNIIPC Vost Prom Zone Cholponatisky 2, Bishkek 720571 Kyrgyz Republic utbegaliev@yahoo.com
Svetlana Uranova Dr., Head of the Laboratory KRSU Kievskai 44, Bishkek 720000 Kyrgyz Republic uransv@yahoo.com

Reviewers


Name Title Affiliation Location Email
Svetlana N. Brzev Instructor Civil and Structural Engineering Technology, British Columbia Institute of Technology Burnaby BC V5G 3H2, Canada sbrzev@bcit.ca