Report: 70

Building Type: Solid brick masonry house with composite hollow clay tile and concrete joist roof slabs

Country: Argentina

Author(s): Virginia I Rodriguez, Maria I Yacante, Sergio Reiloba

Last Updated:

Regions Where Found: Buildings of this construction type can be found in Argentina. Nowadays, this housing type represents about 30% of all the houses built in the capital city of the province of San Juan, reaching 70% in certain neighborhoods. This type of housing construction is commonly found in urban areas.

Summary: This housing type is found in the urban areas of the Province of San Juan. It is a one-story, detached or semi-detached building, mainly used as a single-family house. The strength of this construction type is due to its solid brick walls confined with concrete tie-beams and tie-columns. The roof slabs are of composite concrete and masonry hollow clay tile construction, which form a diaphragm tied to the walls. The deficiency of this type of construction is found in the slabs which suffer serious deterioration due to the effects of humidity. This housing type is expected to have good seismic behaviour.

Length of time practiced: 25-60 years

Still Practiced: Yes

In practice as of:

Building Occupancy: Single dwelling

Typical number of stories: 1

Terrain-Flat: Typically

Terrain-Sloped: 3

Comments:

Plan Shape: Rectangular, solid

Additional comments on plan shape:

Typical plan length (meters): 11

Typical plan width (meters): 8.5

Typical story height (meters): 2.8

Type of Structural System: Masonry: Confined Masonry: Clay brick masonry with concrete posts/tie columns and beams

Additional comments on structural system: Lateral load-resisting system: Confined solid brick masonry with concrete tie columns and bond beams. Gravity load-bearing system: Confined solid brick masonry with concrete tie columns and bond beams.

Gravity load-bearing & lateral load-resisting systems:

Typical wall densities in direction 1: 3-4%

Typical wall densities in direction 2: 5-10%

Additional comments on typical wall densities: Total wall area/plan area: 0.15 Direction Y: 0.06 Direction X: 0.03

Wall Openings: This housing type has five (5) windows and two (2) doors. It has a main window of about 3.5 m#, other windows have an area that varies between 1 m#, and 1.5 m#. The area of the two doors varies between 1.70 m# and 2 m#. All these openings are placed next to or very near the tie columns. 11.20% is the percentage for the overall window and door area as a fraction of the overall wall surface area.

Is it typical for buildings of this type to have common walls with adjacent buildings?: No

Modifications of buildings: Typical patterns of modification observed in this housing type is the extension of the dining room up to the building line and/or a garage. The most common final plan configuration is the “L” shape.

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: The slabs are made of concrete ribs and precast clay joists, with concrete topping cast in-situ. The floor/roof system is considered to be a rigid diaphragm.

Type of Roof System: Roof system, other

Additional comments on roof system: The slabs are made of concrete ribs and precast clay joists, with concrete topping cast in-situ. The floor/roof system is considered to be a rigid diaphragm.

Additional comments section 2: Typical separation distance between buildings: 3 meters

Who is involved with the design process? EngineerArchitect

Roles of those involved in the design process: Architects are in charge of the architectural design and they are sometimes responsible for the construction process of this housing type. Engineers work in structural design and sometimes in the construction process too.

Expertise of those involved in the design process: This construction type was most prevalent between 1950 and 1970. Nowadays it is rarely built. Architects and engineers involved in the design and construction process acquired a good level of expertise since the reconstruction of the city of San Juan after the earthquake of 1944.

Who typically builds this construction type? Other

Roles of those involved in the building process: The builder usually does not live in this construction type. This type of building is designed and built by professionals.

Expertise of those involved in building process:

Construction process and phasing: This construction type is built by a construction company. The construction process begins with the digging and filling of the foundations. Then the frame of low reinforcement concrete beam and the columns are placed, later the beams are filled; the masonry is erected and the columns are filled. Finally, the frames of the top reinforcement beams are placed and the slab is built to fill with concrete all the structure at once. This construction process does not need many tools. The tools and equipment typically used are: shovels, hoes, baskets, pliers, levels, cement mixers, etc. This building is typically constructed incrementally. This construction type is designed for its final constructed size , but it is usually extended. The extensions are generally built without the participation of an architect or an engineer.

Construction issues:

Is this construction type address by codes/standards? Yes

Applicable codes or standards: “C#digo de la Edificacion de la Provincia de San Juan” The first code/standard addressing this type of construction was issued1951; the most recent code/standard addressing this construction was issued 1983. Applicable national building code, material codes and seismic code/standards: “Normas Argentinas para Construcciones Sismorresistentes” (INPRES-CIRSOC 103 Rules - 1983)The seismic code: “Normas Argentinas para Construcciones Sismorresistentes” (Reglamento INPRES-CIRSOC 103) first issued in November 1983, and nowadays in current use, allows the construction of ribbing slabs. The most recent code/standard addressing this construction type issued was 1983.

Process for building code enforcement: The process of application of the Building Code is -in general- appropriate. In the province of San Juan there is an official entity called Direccion de Planeamiento y Desarrollo Urbano (Planning and Urban Development Secretary) which examines and approves the projects (the functional design and the structural calculus). This office also examines the foundations and the structure (plinth, columns, beams, slabs) that must be in accordance with the previously approved project.

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:

Typical problems associated with this type of construction: Humidity damages the slabs made of clay blocks. This kind of slab generally last for 50 years.

Who typically maintains buildings of this type? Owner(s)

Additional comments on maintenance and building condition: There is no careful maintenance of the building.

Unit construction cost: 450 $US/m.sq.

Labor requirements: This construction type requires the approval of the architectural plans, the structural plans, and the sanitary installations plans by the provincial authorities; it also needs the electrical installation plans and the building permit given by the municipal authority. Nowadays, the gas installation plans are examined and approved by a private entity. This type of construction needs about 3 or 4 months to complete the construction.

Additional comments section 3:

Patterns of occupancy: One family.

Number of inhabitants in a typical building of this construction type during the day: 5-10

Number of inhabitants in a typical building of this construction type during the evening/night: 5-10

Additional comments on number of inhabitants:

Economic level of inhabitants: Middle-income class

Additional comments on economic level of inhabitants: Ratio of housing unit price to annual income: 1:1 or better

Typical Source of Financing: Commercial banks/mortgages

Additional comments on financing:

Type of Ownership: Own with debt (mortgage or other)

Additional comments on ownership:

Is earthquake insurance for this construction type typically available?: No

What does earthquake insurance typically cover/cost: Insurance does not cover earthquakes, and in fact they make explicit that there is no coverage for catastrophe.

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:

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Damage patterns observed in past earthquakes for this construction type: In the Capital city of San Juan Province, located 100 kilometers from the epicenter and the intensity was between VI and VII per the MMI scale. The buildings of this construction type suffered minor damages.

Additional comments on earthquake damage patterns: Diagonal shear cracks in buildings with poor construction quality.

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.

Additional comments on structural and architectural features for seismic resistance: For maintenance, both kinds of situations (true and false) are present in this construction type because the slab deteriorates with humidity.

Vertical irregularities typically found in this construction type: Other

Horizontal irregularities typically found in this construction type: Other

Seismic deficiency in walls: No deficiency

Earthquake-resilient features in walls: The required wall resistance necessary in the area is 0.02 in accordance with INPRES-CIRSOC 103. The common densities of this construction type in a normal direction at the front is 0.06; and in a parallel direction at the front 0.03. They generally offer a high resistance capacity, even under the present standards.

Seismic deficiency in frames:

Earthquake-resilient features in frame:

Seismic deficiency in roof and floors: The structure is frequently rusted because the roof has deficient waterproof insulation.

Earthquake resilient features in roof and floors:

Seismic deficiency in foundation:

Earthquake-resilient features in foundation:

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

Additional comments section 5:

Additional comments on seismic strengthening provisions:

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? 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:

• Interrelations Between Architectural Design and Structural Design in High Seismic Risk Areas Unversidad Nacional de San Juan, San Juan, Argentina 1989

• Interrelations Between Architectural Design and Urban Design in High Seismic Risk Areas Universidad Nacional se San Juan, Argentina 1994

• The 1951 Building Code of the Province of San Juan

• Argentinean Standards for Earthquake Resistant Constructions (INPRES-CIRSOC 103 Rules) 1993