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 #:59
Building Type: Reinforced concrete frame with concrete shear walls - dual system
Country: SYRIAN ARAB REPUBLIC
Author(s): Adel Awad
Hwaija Bassam
Isreb Talal
Last Updated:
Regions Where Found: Buildings of this construction type can be found in the main cities of Syria like Damascus, Aleppo, Latakia, Homs, and Hama. This type of housing construction is commonly found in urban areas.
Summary:

These buildings are characterized by a combination of shear walls ...

Length of time practiced: Less than 25 years
Still Practiced: Yes
In practice as of:
Building Occupancy: Residential, 20-49 units
Typical number of stories: 6-15
Terrain-Flat: Typically
Terrain-Sloped: Typically
Comments:


 

Features

 

 

Plan Shape Rectangular, solid
Additional comments on plan shape
Typical plan length (meters) 30
Typical plan width (meters) 20
Typical story height (meters) 3.1
Type of Structural System Structural Concrete: Moment Resisting Frame: Dual system Frame with shear wall
Additional comments on structural system The vertical and lateral load-resisting system is a dual system. Shear walls and frames (columns, beams) carry gravity loading. We can assume that the shear walls provide adequate strength and stiffness to control lateral displacements.
Gravity load-bearing & lateral load-resisting systems
Typical wall densities in direction 1 3-4%
Typical wall densities in direction 2 3-4%
Additional comments on typical wall densities The typical structural wall density is up to 3 %. The ratio between total wall area/plan area is 1 to 3% (for each floor).
Wall Openings Area of openings/walls surface area= 20% for inner walls and 40% for outer walls.
Is it typical for buildings of this type to have common walls with adjacent buildings? No
Modifications of buildings Buildings of this type haven't a lot of modifications yet.
Type of Foundation Shallow Foundation: Reinforced concrete isolated footingShallow Foundation: Reinforced concrete strip footingShallow Foundation: Mat foundation
Additional comments on foundation
Type of Floor System Other floor system
Additional comments on floor system waffle slabs (cast-in-place), solid slabs (precast)
Type of Roof System Roof system, other
Additional comments on roof system waffle slabs (cast-in-place), solid slabs (precast)
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: ConcreteCharacteristic strength:1-3/18-25/1-2 Mix proportions: 1:2:4
Foundations ConcreteCharacteristic strength:1-3/18-25/1-2 Mix proportions: 1:2:4
Floors SteelCharacteristic strength:360-420; Deformed bars
Roof SteelCharacteristic strength:360-420; Deformed bars
Other Characteristic strength"360-420; Deformed bars

Design Process


Who is involved with the design process? EngineerArchitect
Roles of those involved in the design process The designer may visit the construction site, at request.
Expertise of those involved in the design process The structural engineer will have 5 years of studies and more than 5-10 years of experience.

Construction Process


Who typically builds this construction type? Other
Roles of those involved in the building process It is built by developers and sold to the people who may live in this construction type.
Expertise of those involved in building process The construction engineer may have 5 years of studies and less experience than the structure engineer.
Construction process and phasing The owner of the land will hire an architectural office and structural engineer to design the building. They will use modern equipment. The construction of this type of housing takes place in a single phase. Typically, the building is originally 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 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 but the normal Syrian Building Code is used from 1972. The year the first code/standard addressing this type of construction issued was 1972. The most recent code/standard addressing this construction type issued was 1997.
Process for building code enforcement The building design must follow the Syrian Code 1995. In case of damage arbitration process may take place at the court of justice. There is compulsory inspection during the construction and good revision of the structural project.

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? Owner(s)Renter(s)
Additional comments on maintenance and building condition

Construction Economics


Unit construction cost A unit construction may cost 170-300 USD/m# (USD =50 Syrian pound (SP), on market rate).
Labor requirements One floor per month.
Additional comments section 3

 

Socio-Economic Issues

 

 

Patterns of occupancy Each building typically has 21-50 housing unit(s). 45 units in each building. One family typically occupies one unit.
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 Middle-income classHigh-income class (rich)
Additional comments on economic level of inhabitants Ratio of housing unit price to annual income: 4:1 Notes: 1. Below are the general guidelines related to the economic status of the inhabitants: Very Poor = lowest 10% of the population (per GDP) Poor = lowest 30% of the population Middle Class = from the lowest 30% up to the top 20% of the population Rich = top 20% of the population. Additional comments: GNP per capita, in 1997, was $1120. GDP per capita, in 1996, was $1288. Economic Level: For Middle Class the Housing Unit Price is 25000 and the Annual Income is 6000. For Rich Class the Housing Unit Price is 40000 and the Annual Income is 15000.
Typical Source of Financing Owner financedPersonal savingsCommercial banks/mortgages
Additional comments on financing
Type of Ownership RentOwn outrightOwn with debt (mortgage or other)Long-term leaseOther
Additional comments on ownership Other: Ownership by heritage.
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
1719Aleppo
1759Damascus
1796Lattakia
1822Aleppo/Al-jaziereh
1827Harem/ Aleppo
5.5(MMI) VIII
7.5(MMI) X
6(MMI) VIII
7(MMI) IX-X
6(MMI) VIII

Past Earthquakes


Damage patterns observed in past earthquakes for this construction type Data about earthquakes taken from (Ambraseys, 1983), starting from 18th Century up to date. But estimation of values (Magnitude M and Maximum Intensity MMI) were made by us depending on our findings and experience. Most of the building destroyed were of adobe and stone masonry particularly in urban regions.
Additional comments on earthquake damage patterns

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)FALSE
Building Configuration-HorizontalThe building is regular with regards to the plan. (Specify in 5.4.2)FALSE
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. N/A
Wall OpeningsN/A
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 No flexural tension reinforcement; and no confinement at the wall ends.
Earthquake-resilient features in walls
Seismic deficiency in frames No special transverse reinforcement at the critical region (joints).
Earthquake-resilient features in frame
Seismic deficiency in roof and floors Weak connection between roof, floors and walls; and no lintel beams.
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 Seismic strengthening has not been done in Syria so far.
Has seismic strengthening described in the above table been performed? No
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

Statistical Abstract 1999 Central Bureau of Statistic, Damascus 1999


Earthquake Damage in the Arabic Region Ambraseys,N,N. Assessment and Mitigation, UNESCO publication , pp. 11-15 1993


Scientific Fundamentals for Assessment and Mitigation of Earthquake Risk in Syria Awad,A. Damascus University Journal ("Issues of Applied Research") Vol. 9, No 33-34, pp.21-47 1993


Human Development Report 1999 United Nation Development Program (UNDP) Oxford University Press, NY 1999


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


Syrian Code for Earthquake Resistant Design and Construction of Building Syrian Engineers Order, Damascus Damascus 1995


European Marcoseismic Scale 1998 (EMS98) Gruenthal,G. European Seismological Commission (ESC), Luxembourg 1998


Authors




Name Title Affiliation Location Email
Adel Awad Civil Engineer/Professor University of Tishreen P.O. Box 1385, Latakia , SYRIAN ARAB REPUBLIC tuniv-lat@net.sy
Hwaija Bassam Civil Engineer/Associate Professor, University of Tishreen P.O. Box 1385, Latakia , SYRIA tuniv-lat@net.sy
Isreb Talal Civil Engineer University of Tishreen, Latakia , SYRIA tuniv-lat@net.sy

Reviewers


Name Title Affiliation Location Email
Ravi Sinha Professor Civil Engineering Department Indian Institute of Technology Bombay rsinha@civil.iitb.ac.in