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 #:3
Building Type: Steel frame buildings with shear walls
Country: Chile
Author(s): Elias Arze L.
Last Updated:
Regions Where Found: Buildings of this construction type can be found in mainly large cities like Santiago, Concepcion, Valdivia, Temuco, Villarrica. Percentage of total area built is below 2 %. This type of housing construction is commonly found in urban areas.
Summary:

These buildings are modern steel composite structures ranging from 3 ...

Length of time practiced: 76-100 years
Still Practiced: Yes
In practice as of:
Building Occupancy: Residential, 50+ units
Typical number of stories: 3 to 5 and 6 to 24
Terrain-Flat: Typically
Terrain-Sloped: Off
Comments: This construction type has been used since 1965-70. Some buildings include commercial ground floor too.


 

Features

 

 

Plan Shape Rectangular, solid
Additional comments on plan shape
Typical plan length (meters) 10-20
Typical plan width (meters) 20-30
Typical story height (meters) 3
Type of Structural System Steel: Moment Resisting Frame: With cast in-situ concrete walls
Additional comments on structural system The vertical load-resisting system is steel braced frame. Steel deck slabs, prestressed concrete slabs, reinforced concrete slabs. Steel beams, normally composite. Steel columns and shear walls. The lateral load-resisting system is steel structural walls. Dual construction, shear walls combined with rigid steel frame. Up to 5 stories x or v or ^ braced shear walls. Over 5 stories - reinforced concrete slip or jump formed walls.
Gravity load-bearing & lateral load-resisting systems Typical buildings have shear wall, light weight partitions and some concentric brace frames.
Typical wall densities in direction 1 1-2%
Typical wall densities in direction 2 1-2%
Additional comments on typical wall densities
Wall Openings 20 to 30%
Is it typical for buildings of this type to have common walls with adjacent buildings? No
Modifications of buildings
Type of Foundation Shallow Foundation: Reinforced concrete isolated footingShallow Foundation: Reinforced concrete strip footingShallow Foundation: Mat foundationDeep Foundation: Reinforced concrete bearing pilesDeep Foundation: Steel bearing pilesOther Foundation
Additional comments on foundation It consists of reinforced concrete end-bearing piles and steel end-bearing piles. Reinforced concrete isolated footing. Reinforced concrete strip footing. Mat foundation. Reinforced concrete bearing piles. Steel bearing piles. Floating deep foundations.
Type of Floor System Composite steel deck and concrete slabOther floor system
Additional comments on floor system Other: Post-tensioned slabs, composite steel deck without concrete slab. Floors and roofs are considered as rigid diaphragms.
Type of Roof System Composite steel roof deck and concrete slabRoof system, other
Additional comments on roof system Other: composite steel deck without concrete slab. Floor and roof are considered as rigid diaphragm.
Additional comments section 2 Buildings are widely spaced, at a minimum of 10 meters.

 

Building Materials and Construction Process

 

 

Description of Building Materials


Structural Element Building Material (s)Comment (s)
Wall/Frame Reinforced concrete rebars Structural steel frames25-30 MPa 420-280 MPa steel: 250 MPa (36 ksi)
Foundations
Floors RC slabs Steel beams25-30 MPa 250 MPa
Roof RC slabs Steel beams25-30 MPa 250 MPa
Other

Design Process


Who is involved with the design process? EngineerArchitectOther
Roles of those involved in the design process Developer hires architects, engineers and construction firms. Architects and engineers must visit the job and provide general supervision. They usually must approve construction contracts.
Expertise of those involved in the design process Architects have 5 university years and typically over 5 years of experience. Engineers have 6 university years and typically over 5 years of experience. Construction companies are headed by engineers or architects. Experience about 10 years. The same for fab shops. In steel frame buildings, review of design and independent inspection are typical.

Construction Process


Who typically builds this construction type? Other
Roles of those involved in the building process Developer hires architects, engineers and construction firms.
Expertise of those involved in building process Construction companies are headed by engineers or architects. Experience about 10 years. The same for fab shops. In steel frame buildings, review of design and independent inspection are typical.
Construction process and phasing Construction of this type typically takes place over time, buildings are originally designed for their final constructed size.
Construction issues

Building Codes and Standards


Is this construction type address by codes/standards? Yes
Applicable codes or standards Chilean seismic codes NCh433.Of96 & NCh2369 are mandatory. AISC and ACI codes corrected to meet seismic codes are applied. Code/standard addressing this type of construction was first issued 1957. National building code, material codes and seismic codes/standards: NCh433.Of96, seismic design for buildings; NCh2369.Of01 seismic design of industrial buildings, NCh428.Of57code design for steel structures. Most recent code/standard addressing this construction type was issued: 1957, but now there is a draft to modify that code that partially follows AISC and AISI.
Process for building code enforcement Design review by peers (may belong to design firm) is normal. Independent inspection is normal in steel framed buildings.

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 Low cost apartments, up to 5 floors, UF 10/sq m (US $300/sq m). Normal, up to 5 floors, UF 20/sq m (US $600/sq m). High-rise, 30/sq m (US$ 900/sq m).
Labor requirements 1.5 to 2.5 floors per month.
Additional comments section 3

 

Socio-Economic Issues

 

 

Patterns of occupancy One family per unit. Each building typically has 51-100 housing unit(s). For buildings up to 5 floors: 15 - 20 units. For those up to 20 floors: 150 - 200 units.
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 classHigh-income class (rich)
Additional comments on economic level of inhabitants House Price/Annual Income ratio: Poor: 4.0 - 4.5, Middle Class: 2.5 - 3.0, Rich: 2.5 - 3.0 Ratio of housing unit price to annual income: 1:1 or better
Typical Source of Financing Owner financedPersonal savingsCommercial banks/mortgagesOther
Additional comments on financing Ministry of Housing gives low interest loans for poor or low middle class owners.
Type of Ownership RentOwn with debt (mortgage or other)Units owned individually (condominium)Owned by group or pool
Additional comments on ownership Some buildings may belong to an institution
Is earthquake insurance for this construction type typically available? Yes
What does earthquake insurance typically cover/cost Repairs to same conditions before the earthquake. Occasionally, time lost.
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 It is on average. Up to 5 floors, 15-20 units. Up to 20 floors, 150-200

 

Earthquakes

 

 

Past Earthquakes in the country which affected buildings of this type


YearEarthquake Epicenter Richter Magnitude Maximum Intensity
1960Valdivia
1985Llolleo
9.5XI (MMI)
7.8VIII (MMI)

Past Earthquakes


Damage patterns observed in past earthquakes for this construction type There were many connections of the type that failed in Northridge, Loma Prieta and Kobe. No damage in any of them. Probable causes: # Chilean Building Code allows maximum drift about 1/2 of USA. # Periods are approximately 0.05N instead of 0.1N (N=floors) # No jumbo W sections are used # Beams and columns are welded to stress relieved plates. A good example of good behavior are the seven 4 story-buildings from Poblacion Republica Popular China, located in Vina del Mar. They are 46 X 10.6 m in plan, have moment resisting frames in both directions and 12 cm reinforced concrete slab. In the longitudinal direction the span is 4.6 cm. The buildings were designed according to NCh428.Of 57 with A42-27ES steel.
Additional comments on earthquake damage patterns No damage in serious earthquakes in 1960 (M9.5) and in 1985 (M7.8)

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 OpeningsN/A
Quality of Building MaterialsQuality of building materials is considered to be adequate per the requirements of national codes and standards (an estimate). TRUE
Quality of WorkmanshipQuality of workmanship (based on visual inspection of a few typical buildings) is considered to be good (per local construction standards).TRUE
MaintenanceBuildings of this type are generally well maintained and there are no visible signs of deterioration of building elements (concrete, steel, timber).TRUE

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 None
Earthquake-resilient features in walls Regular buildings in plan and height good design and construction practice
Seismic deficiency in frames None
Earthquake-resilient features in frame
Seismic deficiency in roof and floors None
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 It has not been required in steel framed buildings
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

Edificios de Acero J.Monge, S.Campino, and R.Sharpe a Chapter in "El Sismo de Marzo 1985, Chile", (Ed.) J.Monge 1985


Authors


Name Title Affiliation Location Email
Elias Arze L. President ARA Consulting Engineers Av. J.P. Alessandri 1495 Chile amarquez@ara.cl

Reviewers


Name Title Affiliation Location Email
Ofelia Moroni Civil Engineer/Assistant Professor University of Chile Santiago , CHILE mmoroni@cec.uchile.cl