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 #:76
Building Type: Load-bearing wall buildings protected with the "sliding belt" base isolation system
Country: Kyrgyzstan
Author(s): Jacob Eisenberg
Svetlana Uranova
Marat Abdibaliev
Ulugbek T. Begaliev
Last Updated:
Regions Where Found: There are about 30 base isolated buildings in Bishkek (Kyrgyzstan). In 1982, two 3-story brick masonry wall buildings were built in the area with high seismicity (9-10 per MSK scale). A residential block (microdistrict) of 9-story concrete large panel buildings protected with seismic isolation belt was built in the period 1983-1990. Several 9-story large panel concrete buildings were built in the center of Bishkek. One of the buildings is also equipped with a dynamic damper. Some buildings with seismic isolation belt were built in Kazahkstan and Russia (Kamchatka).
Summary:

Sliding belt is a base isolation system developed for seismic ...

Length of time practiced: Less than 25 years
Still Practiced: Yes
In practice as of:
Building Occupancy: Residential, 50+ units
Typical number of stories: 9
Terrain-Flat: Typically
Terrain-Sloped: 3
Comments:


 

Features

 

 

Plan Shape Rectangular, solid
Additional comments on plan shape Typical shape of a building plan of this housing type is rectangular.
Typical plan length (meters) 50.4
Typical plan width (meters) 10.8
Typical story height (meters) 3
Type of Structural System Structural Concrete: Precast Concrete: Large panel precast wallsOther: Seismic Protection Systems: Building protected with base-isolationOther: Seismic Protection Systems: Building protected with seismic dampersOther
Additional comments on structural system Lateral load-resisting system: Lateral load-resisting system includes the superstructure (e.g. large reinforced concrete panel construction or brick masonry construction) and the foundation. The sliding belt is installed at the base of the building, between the foundation and the superstructure. The sliding belt consists of the following elements: a) sliding supports, including the stainless steel plates attached to the foundation and the Teflon (PTFE) plates attached to the superstructure, b) reinforced rubber restraints for horizontal displacements (horizontal stop), and c) restraints for vertical displacements (uplift). The steel plates are 2 mm thick; the plate width is approximately equal to the foundation width, and the length depends on the size of the Teflon plate located at the center (usually projects by 150 mm on each side). The dimensions of Teflon plates are usually 400 mm x 400 mm for 9-story buildings and 200 mm x 200 mm for 5-story buildings; typical plate thickness is 4 to 6 mm. Horizontal stops consist of rigid reinforced structure with steel plates and a rubber damper. Vertical stops consist of steel anchor bolts. A typical large panel building (plan dimensions 39.6m x10.8 m) is equipped with 63 sliding supports and 70 horizontal and vertical restraints. A gap between rubber damper and sliding support for a 9-story building is usually 50 mm; this means that the horizontal stops will be activated once the building has moved by 50 mm in the horizontal direction. The recommended "seismic gap" ranges from 100 to 120 mm. In buildings constructed in Bishkek 300 mm gap was provided. No special provisions were made for flexible water supply and electrical facilities in the buildings protected with this system. Once the earthquake base shear force exceeds the level of frictional force developed in the sliding belt (approximately equal to 10% of the building weight), the building (superstructure) starts to slide relative to the foundation. The design recommendations state that the frictional coefficient value for Teflon-steel sliding is 0.1 (unless a different value is obtained by the tests). However, it should be noted that once the sliding is initiated, building continues to vibrate and restraints get activated as well. The analysis is based on rather complex formulas based of research studies that have been modified for the design practice. Simplified design calculations are not commonly used in the design of this construction type; comprehensive analysis is deemed required. Seismic design of the superstructure is performed based on the results of the dynamic analysis. The level of seismic forces (seismic demand) is reduced as compared to the conventional buildings by up to 50%. The sliding belt scheme was developed by CNIISK Kucherenko in Moscow around 1975; other institutes in the former Soviet Union also contributed to the development. Late L. S. Kilimnik was the leader in the development of the seismic belt system. The first design applications of seismic belt scheme were made in Bishkek in 1982. Two types of tests, static tests under horizontal loads and dynamic tests of full-scale buildings using the vibration equipment, were conducted in 1980. The design recommendations for base isolated buildings of this type were developed based on the results of these tests. Gravity load-bearing system: Gravity load-bearing structure is a conventional building construction, either large panel construction or brick masonry construction. Majority of base isolated buildings of this type are large panel concrete buildings with monolithic joints (seria 105). This construction type was described in detail in another contribution from Kyrgyzstan (by S. Uranova and U. Begaliev). Brick masonry buildings are 3-story high and are equipped with the reinforced concrete members and steel mesh, typical for brick masonry construction in the former Soviet Union. It should be noted, however, that the construction of conventional 3-story high brick masonry construction was otherwise not permitted in high seismic zones (intensity 9 to 10 on the MSK scale).
Gravity load-bearing & lateral load-resisting systems
Typical wall densities in direction 1 10-15%
Typical wall densities in direction 2 10-15%
Additional comments on typical wall densities Total wall area/plan area is about 0.14. Wall density in two principal directions is not equal; in one of the directions wall density is less by 20 to 30% as compared to the other direction.
Wall Openings Wall openings are same as in typical large panel buildings. Usually, for a 3.6m long panel, a window size is 1.82m(width)x1.53m(height); for 2.7m long panel - window size is 1.24m(width)x1.53m(height). The size of a door is 0.9m(width)x2m(height). The size of a balcony door (together with window) is either 2.25m or 1.66 m(width) or and 1.9m (height). Overall window and door areas make up to 20% of the overall wall area. There are 16 windows for a building with 10.8m x 25.2m plan dimensions.
Is it typical for buildings of this type to have common walls with adjacent buildings? No
Modifications of buildings Typical patterns of modification include the perforation of walls with door openings and the creation of door opening instead of the window.
Type of Foundation Shallow Foundation: Reinforced concrete strip footing
Additional comments on foundation Foundation include seismo-isolation sliding belt
Type of Floor System Other floor system
Additional comments on floor system Structural Concrete: Precast solid slab panels
Type of Roof System Roof system, other
Additional comments on roof system Structural Concrete: Precast solid slab panels
Additional comments section 2 When separated from adjacent buildings, the typical distance from a neighboring building is 10 meters.

 

Building Materials and Construction Process

 

 

Description of Building Materials


Structural Element Building Material (s)Comment (s)
Wall/Frame Wall: Reinforced concreteCharacteristic Strength- Concrete: 30-35 MPa ( cube compressive strength) Steel: 390 MPa (steel yield strength)
Foundations Reinforced concreteCharacteristic Strength- Concrete: 10-15 MPa ( cube compressive strength) Steel: 295 MPa (steel yield strength)
Floors Reinforced concreteCharacteristic Strength- Concrete: 30-35 MPa ( cube compressive strength) Steel: 390 MPa (steel yield strength)
Roof Reinforced concreteCharacteristic Strength- Concrete: 30-35 MPa ( cube compressive strength) Steel: 390 MPa (steel yield strength)
Other

Design Process


Who is involved with the design process? EngineerArchitectOther
Roles of those involved in the design process Design of buildings of this construction type was done completely by engineers and architects. Researchers also participated in the development of design documentation. Engineers played a leading role in each stage of construction.
Expertise of those involved in the design process The expertise required for the design and construction of this type is available. Building designs were prepared by design institutes. The academic background of the designers is the same as for conventional construction. It is not required to have designers with high academic degrees eg. M.Sc. and Ph.D. on the team.

Construction Process


Who typically builds this construction type? Builder
Roles of those involved in the building process
Expertise of those involved in building process Construction of base isolated buildings and the approval of the designs was controlled by research institutes (State Experts) like any other new construction performed in accordance with the Building Code requirements.
Construction process and phasing Specialized construction companies make precast concrete elements and perform casting of concrete in-situ. Precast elements are fabricated at the plants. In case of precast foundation and superstructure construction, steel and Teflon plates are installed at the plant. Horizontal restraints (rubber dampers) and vertical restraints are installed at the site. The main construction equipment is the same as in the case of conventional concrete construction and it includes crane, welding equipment and concrete mixers. This building is not typically constructed incrementally and is designed for its final constructed size.
Construction issues

Building Codes and Standards


Is this construction type address by codes/standards? Yes
Applicable codes or standards SNiP II-7-81. Building in Seismic Regions.Design code The first (still most recent) code/standard addressing this type of construction was issued 1981. SNiP II-7-81. Building in Seismic Regions. Design code. CNIISK. Recommendations for Design of Buildings with Seismic Isolation Belt and Dynamic Vibration Dampers, Moscow, 1984.
Process for building code enforcement Building permit will be given if the design documents have been approved by the State Experts. State Experts check the compliance of design documents with pertinent Building Codes. According to the building bylaws, a building cannot be used without the formal approval of a special committee. The committee gives the approval if design documents are complete and the construction has been carried out in compliance with the 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 Installation/construction of sliding belt is a rather complex technological problem as compared to the conventional construction.
Who typically maintains buildings of this type? BuilderOwner(s)Renter(s)
Additional comments on maintenance and building condition

Construction Economics


Unit construction cost For load-bearing structure only (including the seismic belt) the cost is about 230$/m.sq. For a similar prefabricated concrete panel building (seria 105) without a seismic belt the construction cost would be US$ 150-200/m.sq. Therefore, the increase in unit cost due to the installation of seismic belt is in the range from 15 to 50 %.
Labor requirements It would take from 8 to10 months for a team of 15 workers to construct a load-bearing structure.
Additional comments section 3

 

Socio-Economic Issues

 

 

Patterns of occupancy In general, in a building of this type there are 3-4 housing units per building unit ("Block-Section"). One family occupies one housing unit. Depending on the size of the building (number of 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 50% poor, and 50% middle class inhabitants occupy buildings of this type Ratio of housing unit price to annual income: 1:1 or better
Typical Source of Financing Owner financedPersonal savingsGovernment-owned housing
Additional comments on financing Until 1990 (the breakdown of the Soviet Union), the financing for buildings of this type had been provided by the Government. At the present time, all new and existing apartment buildings are privately owned.
Type of Ownership RentOwn outrightUnits owned individually (condominium)
Additional comments on ownership These buildings were constructed at the time of the former Soviet Union and the construction was sponsored by the Government. However, at the present time all apartments are owned by the residents.
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

Past Earthquakes


Damage patterns observed in past earthquakes for this construction type This building type was tested by special vibration equipment that applied loads equal to design seismic loads.
Additional comments on earthquake damage patterns Damage of bearing structures of upper floors less than in similar buildings without seismic protection systems.

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.TRUE
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.TRUE
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 Application to large panel construction - Panel joints; quality of construction,especially welding of reinforcing bars from the adjacent panels and filling the gaps between the panels with concrete is not satisfactory in some cases: poor quality of panel joints and brick masonry
Earthquake-resilient features in walls Due to a large number and uniform distribution of panel joints existing in one building, deficient construction of some joints does not have a major impact on the overall seismic resistance of the building as a whole.
Seismic deficiency in frames
Earthquake-resilient features in frame
Seismic deficiency in roof and floors Within the panel joints- quality of construction, especially welding of reinforcing bars from the adjacent panels and filling the gaps between the panels with concrete is not satisfactory in some cases.
Earthquake resilient features in roof and floors Includ(ing) a large number and uniform distribution of panel joints in one building, deficient construction of some joints does not have a major impact on the overall seismic resistance in the building as a whole
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? No. Buildings of this type are already strengthened by means of seismic belt.
Was the work done as a mitigation effort on an undamaged building or as a repair following earthquake damages? N/A.
Was the construction inspected in the same manner as new construction? N/A.
Who performed the construction: a contractor or owner/user? Was an architect or engineer involved? N/A.
What has been the performance of retrofitted buildings of this type in subsequent earthquakes? N/A.
Additional comments section 6

 

References

CNIISK. Recommendations for Design of Buildings with Seismic Isolation Belt and Dynamic Vibration Dampers, Moscow, 1984. (in Russian)


King, Stephanie, Vitaly Khalturin and Brian E. Tucker. Seismic Hazard and Buildings Vulnerability in Post-Soviet Central Asia Republics. Proceedings of the NATO Advanced Research Workshop on Earthquake Risk Management Strategies for Post-Soviet Central Asian Republics, Almaty, Kazakhstan, Kluwer Academic Publishers, Dordrecht, Netherlands, 1999.


Uranova, S.K., and Imanbekov, S.T. Building and Construction Design in Seismic Regions-Handbook. Kyrgyz NIIP Stroitelstva, Building Ministry Kyrgyz Republic, Bishkek, Kyrgyz Republic, 1996 (in Russian).


Eisenberg, J. et al. Seismoisolation in Russia and former USSR Countries: Recent Developments. Proceedings of the International Post-SMiRt Conference Seminar, Cheju, Korea, Korea Earthquake Engineering Research Center, Seoul, Korea, 1999,Vol.1, p. 99-115.


Eisenberg, J. et al. Applications of Seismic Isolation in the USSR. Proceedings of the Tenth World Conference on Earthquake Engineering, Balkema, Roterdam, Vol.4, 1992, p. 2039-2044.


Eisenberg, J. and Bealiev, V.S. Operating Experience in Designing and Construction of the System of Special Seismic Isolation of Buildings and Constructions in the former Russia. Proceedings of the Eleventh World Conference on Earthquake Engineering, Pergamon, Elsevier Science Ltd., Oxford, England, 1996, Disc 1, Paper No. 263.


Experimental Buildings with Seismic Protection in Petropavlovsk-Kamchatskiy (in Russian)


Authors





Name Title Affiliation Location Email
Jacob Eisenberg Pr., Chairman Russian National Committee for Earthquake Engineering 4 Berezhkovsky Embankment Art 110, Moscow 121059 Russia seismo@online.ru
Svetlana Uranova Dr., Head of the Laboratory KRSU Kievskai 44, Bishkek 720000 Kyrgyz Republic uransv@yahoo.com
Marat Abdibaliev Dr.,Chairman Kyrgyzpromproekt Chuy 219-2, Bishkek 720000 Kyrgyz Republic prom@intranet.kg
Ulugbek T. Begaliev Head of Department KNIIPC Vost Prom Zone Cholponatisky 2, Bishkek 720571 Kyrgyz Republic utbegaliev@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