World Housing Encyclopedia Report

Country: Argentina

Housing Type: Confined block masonry house

Contributors:Virginia I RodriguezMaría I YacanteSergio Reiloba

Primary Reviewer:Sergio Alcocer

Created on: 6/5/2002Last Modified: 6/17/2003

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........................................................................................ 2Socio-Economic Issues...................................................................................... 3Structural Features............................................................................................. 4Evaluation of Seismic Performance and Seismic Vulnerability.......................... 8Earthquake Damage Patterns............................................................................ 10Building Materials and Construction Process..................................................... 11Construction Economics.....................................................................................13Insurance............................................................................................................14Seismic Strengthening Technologies................................................................. 15References......................................................................................................... 16Contributors........................................................................................................ 17Figures................................................................................................................18

1 General Information

1.1 CountryArgentina

1.3 Housing TypeConfined block masonry house

1.4 SummaryThis is typically a one-or-two-story residentialbuilding, of detached or semi-detachedconstruction, generally found in the urban areasof San Juan and Mendoza and less frequently inthe rural areas. The walls are made of concreteblock masonry with reinforced concrete columnsand beams that tie the walls together andprovide the strength for the building. One of themain structural deficiencies for this constructiontype lies in the widely different wall densities inthe two orthogonal directions. This deficiencymay be eliminated with appropriate architecturaldesign. This construction type is otherwiseexpected to demonstrate good seismicperformance.

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 construction practice has been followed for 30 years.

1.6 Region(s) Where UsedSan Juan Capital City and the surroundings.

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 OpeningsThe typical house has approximately seven openings, each one with an average area of 2.50 m². Theposition of the openings differs from building to building, however generally there is a front door and aback or side door. There are windows in the family room, in every bedroom and the bathroom. Theopening area is about 13% of the overall wall 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?

The typical separation distance between buildings is 5 meters

2.3 Building ConfigurationThe typical shape of a building plan for this housing type is rectangular.

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 EscapeUsually, there is a front door and a back or side door in the building.

2.6 Modification of BuildingsThis building type hasn't many modifications else.

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3 Socio-Economic Issues

3.1 Patterns of OccupancyA single family per housing unit.

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 X X5 to 1010-20> 20Other

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 /Middle Class X 18000/20000Rich /

Additional Comments: 1. Below are the general guidelines related to the economic status of theinhabitants: Very Poor= lowest 10% of the population (per GDP) Poor= lowest 30% of the populationMiddle Class= from the lowest 30% up to the top 20% of the population Rich= top 20% of the population

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 housingOther

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

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4 Structural Features

4.1 Lateral Load-Resisting SystemEarthquake-resisting structure: concrete block masonry walls with reinforced concrete beams andcolumns.

4.2 Gravity Load-Bearing StructureThe same as earthquake-resisting structure i.e. consisting of concrete block masonry walls withreinforced concrete beams and columns. In some cases, concrete beams and columns are providedwithout the masonry walls, in which case this system behaves as a frame; this depends on thearchitectural design.

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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

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

Other Nervure slab made of concrete with hollow clay blocks and fill-in elements X

Additional Comments: The roof is considered to be a rigid diaphragm

4.6 Typical Plan DimensionsLength: 10 - 10 metersWidth: 10 - 10 meters

4.7 Typical Number of Stories1 - 2

4.8 Typical Story Height3.30 meters

4.9 Typical Span3 meters

Additional Comments: Span variation between the adjacent columns is typically between 3.00 and 3.40

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4.10 Typical Wall Density0.116In the direction X the wall density is 0.03In the direction Y the wall density is 0.08

4.11 General Applicability of Answers to Questions in Section 4This contribution is not based on a case study of one building.

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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 In general, this type of building has no

seismic deficiencies, except when theconstruction is not controlled by anofficial organization.

During the earthquake of 1977 inCaucete, in the capital city of San Juan,located about 100 km from theepicenter, the intensity was between VIIand VIII. The buildings of thisconstruction type sustained no seriousdamage.

Frame (columns,beams)

Generally without seismic deficiencies

Roof and floors No seismic deficienciesOther

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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)1977 Caucete 7.4 IX

Additional Comments: In the Capital city of San Juan, located about 100 km from the epicenter, theintensity was between VII and VIII. The buildings of this construction type sustained the earthquakewithout serious damage.

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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 Hollow concrete

block50 kg/cm² 2 kg/cm² 1:1:5 (cement-lime-sand) 0.20

m X 0.40 m(1) Resistance tocompression (2)Resistance to shearstrength

Foundations concrete 210 kg/cm² 1:3:5 (cement-sand- pebble)0.60 m X 0.25 m

(3) Averageresistance tocompression

Frame Reinforcedconcrete

210 kg/cm² 4200 kg/cm² 1:2:4 (cement-sand-pebble)Column: 0.20 m X 0.20 mBeam: 0.20 m X 0.15 m

Roof and floors Reinforcedconcrete Hollowclay block

210 kg/cm² 4200 kg/cm² 1:2:4 (cement-sand-pebble)

7.2 Does the builder typically live in this construction type, or is it more typicallybuilt by developers or for speculation?The builder usually does not live in this construction type. It is designed and built by professionals andused in housing plans developed and financed by the state.

7.3 Construction ProcessThe construction process is usually carried out by a construction company. It begins with the filling in offoundations, the assembling of the bottom reinforced concrete beams and columns and the casting ofthese beams. Then the block masonry walls are being built and the concrete columns are being cast.Subsequently, the top reinforced concrete beams are assembled and the slab concrete is poured. Thetools and equipment typically used are: spatulas, shovels, hoes, baskets, saws, pliers, levels, cementmixers.

7.4 Design/Construction ExpertiseThe professionals involved in the design and construction process -architects and engineers- have a goodlevel of expertise and great experience in this type of construction, typical in San Juan.

7.5 Building Codes and StandardsYes No

Is this construction type addressed by codes/standards? X

Title of the code or standard: 1951 Building Code of the Province of San Juan, Earthquake-proof NormsConcar 70, Argentinean Earthquake-proof Norms 80 and 1990 INPRES CIRSOC Norms.

7.6 Role of Engineers and ArchitectsArchitects are in charge of the architectural design of the building and sometimes, the constructionprocess. Engineers are in charge of the structural design and of the construction process in general.

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 Construction

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Yes NoConstruction takes place over time (incrementally) XBuilding originally designed for its final constructed size X

Additional Comments: This type of construction is generally designed for its final constructed size, butusually the final size is fulfilled in a later stage, as an extension of the original construction. Sometimesthe owner also builds additional parts, generally without any professional input.

7.9 Building MaintenanceWho typically maintains buildings of this type?BuilderOwner(s) XRenter(s)No oneOther

Additional Comments: Usually, it is the owner who maintains the building, but little or no maintenance isdone.

7.10 Process for Building Code EnforcementThe provincial authorities approve the design and control the construction process.To start the process of construction it is necessary to have the approval of the general and structureplans, the electrical wiring plans, plumbing, and gas plans. This approval is provided by the ProvincialAuthorities. A construction license provided by the Municipal Authorities is also required.

7.11 Typical Problems Associated with this Type of ConstructionThe only problems associated with this type of construction are the considerable dispersion in the qualityof the concrete blocks used and the common lack of maintenance in this type of construction. The qualityof the blocks is controlled by means of standardized trials.

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8 Construction Economics

8.1 Unit Construction Cost (estimate)Unit construction cost per m² of built-up area is approx. US$ 250. This price includes the entire needs ofthe construction.

8.2 Labor Requirements (estimate)To start the process of construction it is necessary to have the approval of the general and structureplans, the electrical wiring plans, plumbing, and gas plans. This approval is provided by the ProvincialAuthorities. A construction license provided by the Municipal Authorities is also required. This type ofbuilding will need approx. 4 months to complete the construction.Workmen must satisfy minimum requirements like some expertise in the making of concrete,bond-beams, tie-columns, slabs cement mortars, and joists as well as in the construction of blockmasonry walls.

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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?NA

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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)

Wall Increase the width of some walls. This has a low increase in theconstruction cost and a high likelihood of enhancing seismic stability. Itis relatively simple to perform.

10.2 Has seismic strengthening described in the above table been performed indesign practice, and if so, to what extent?

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 ReferencesThe 1951 Building Code of the Province of San Juan

Earthquake-proof Norms Concar 70

International Projects Between Architectural Design and Structural Design in High Seismic Risk Areas(building level San Juan, 1989 - San Juan - Argentina)

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12 ContributorsName Virginia I Rodriguez María I Yacante Sergio ReilobaTitle Architect Architect ArchitectAffiliation Professor - Researcher Professor - Researcher Professor - ResearcherAddress Bº UDAP III M.EMblock 1

Piso 1ºAv. Libertador 1068 (s) Napoleón Borini 4955 (o)

City San Juan San Juan San JuanZipcode 5425 5400 5400Country Argentina Argentina ArgentinaPhone 54-264-4342556 54-264-4218409 54-264-4331776Fax 54-264-4342556Email deskjet@impsat1.com.ar cereiloba@mixmail.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 3: Plan of a Typical Building

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FIGURE 4: Critical Structural Details

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FIGURE 5: A Photograph Illustrating Typical Earthquake Damage

FIGURE 6: Illustration of Seismic Strengthening Techniques

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