Report #: 51

Report Date:

Country: PERU

Housing Type:

Housing Sub-Type:

Author(s): Cesar Loaiza, Marcial Blondet, Papa Simona

Last Updated:

Regions Where Found: Buildings of this construction type can be found in all parts of Peru, particularly in the coastal region. This type of housing construction is commonly found in both rural and urban areas.

Summary: This is the most common single-family housing construction practice followed both in urban and rural areas of Peru in the last 45 years. Confined masonry buildings consist of loadbearing unreinforced masonry walls made of clay brick units, confined by cast-in-place reinforced concrete tie columns and beams. These buildings do not have a complete load path in both horizontal directions required for adequate lateral load resistance. However, in spite of that typical houses may show a good seismic performance.

Length of time practiced: 25-60 years

Still Practiced: Yes

In practice as of:

Building Occupancy: Single dwelling

Typical number of stories: 2-3

Terrain-Flat: Typically

Terrain-Sloped: 3

Comments:

Total number of housing units depends on the number of building sections. Typically, for the three-section building, the number

Plan Shape: Rectangular, solidL-shape

Additional comments on plan shape: Rectangular shape or L-shape.

Typical plan length (meters): 10-15

Typical plan width (meters): 5-10

Typical story height (meters): 2.6 - 2.8

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

Additional comments on structural system: The lateral load-resisting system is confined masonry wall system. Masonry shear walls give stiffness to the structure and control lateral drifts. Tie columns and bond beams provide adequate confinement and ductility to the masonry walls. Typical houses have a good wall density in one horizontal direction, but a lower wall density in the other. This makes the house particularly vulnerable in the horizontal direction where the density is lowest. Tie columns have enough longitudinal reinforcement to resist overturning moments. Closely spaced transverse reinforcement at beam-column joints provides adequate ductility to resist seismic forces. Floors/roofs can consider to be rigid diaphragms in the analysis. Typical wall thickness is 150 mm or 250 mm.

In general, the same system as describe above. Floors/roofs transmits gravity loads to the structural walls.

Gravity load-bearing & lateral load-resisting systems: In some cases, rubble stone and massive stone walls have been used.

Typical wall densities in direction 1: 1-2%

Typical wall densities in direction 2: 4-5%

Additional comments on typical wall densities: Typical wall densities for each horizontal direction are 2% and 7%, respectively.

Wall Openings: A typical house has 6 to 10 windows per floor, with a total average size of 3.0 sq m. The position of these openings is variable, but usually is approximately 0.8 to 1.0 m from the floor level in rooms and from 1.8 to 2.0 m in bathrooms.

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

Modifications of buildings: Commonly, owners build interior walls or additional floors for new rooms.

Type of Foundation: Shallow Foundation: Rubble stone, fieldstone isolated footing

Additional comments on foundation: In buildings close to rivers, fieldstone strip footing can be found.

Type of Floor System: Other floor system

Additional comments on floor system:

Type of Roof System: Roof system, other

Additional comments on roof system:

Additional comments section 2: When separated from adjacent buildings, the typical distance from a neighboring building is 0.01 meters.

Who is involved with the design process?: EngineerArchitect

Roles of those involved in the design process: Engineers are in charge of the structural design and construction process. Architects are in charge of the architectural design and could be in charge of the construction process.

Expertise of those involved in the design process: Both, the structural and the construction engineer will have five years of study and minimum work experience of two years.

Who typically builds this construction type?: Contractor

Roles of those involved in the building process: It is typically built by developers.

Expertise of those involved in building process:

Construction process and phasing: Masonry walls are built with serrated edges, and then the tie-columns are cast against them. After that, bond beams, lintels and floors are built simultaneously. Concrete is mixed in machine mixers and taken with wheelbarrows to fill the wood formwork. Tools and equipment used are: hammers, spatulas, wheelbarrows, concrete vibrator and concrete mixers. The construction of this type of housing takes place in a single phase. Typically, the building is originally not designed for its final constructed size. Buildings are originally designed for a specific number of stories. However, it is common that owners decide to build additional floors some years later.

Construction issues

Is this construction type address by codes/standards?: Yes

Applicable codes or standards: Seismic Design Standards E-030. 1977 National Construction Standards, Masonry Standards E-070 1998

Process for building code enforcement: Municipal authorities approve the structural and architectural design for the building. It is a common practice that owners retain a building supervisor to oversee the construction process.

In order to start the construction, it is necessary to get a building permit. Municipal authorities are in charge of giving this permit to builder companies. Each project must have four types of technical drawings: structural drawings, architectural drawings, hydraulic installation drawings, and power installation drawings. Municipal authorities need to approve this technical information to issue a building permit.

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:

Who typically maintains buildings of this type?: BuilderOwner(s)Renter(s)No one

Additional comments on maintenance and building condition:

Unit construction cost: Unit construction cost may vary from 200 to 250 $US/sq m. This price includes the entire construction cost and could change depending on the quality of finishing materials.

Labor requirements: A typical 2-story house will need approximately 90 days (3 months) to complete the construction.

Additional comments section 3: These buildings were constructed using the following construction materials: 2. Exterior walls (2 layers); one layer is made using regular concrete and the other one is made of lightwight concrete (for the purpose of heat insulation). 3. Interior walls are made of regular concrete.

Additional comments on earthquake damage patterns: Shear cracking in the walls (cracks propagate through tie columns).

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.

Vertical irregularities typically found in this construction type: Other

Horizontal irregularities typically found in this construction type: Other

Seismic deficiency in walls: -Inadequate thickness to resist gravity and seismic loads (slender walls). -Inadequate wall density in one direction.

Earthquake-resilient features in walls: Good seismic force transfer.

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

Has seismic strengthening described in the above table been performed?: Yes, parapets are confined and nonstructural walls are isolated from the structure.

Was the work done as a mitigation effort on an undamaged building or as a repair following earthquake damages?: The seismic strengthening was done in a new construction.

Was the construction inspected in the same manner as new construction?: Yes

Who performed the construction: a contractor or owner/user? Was an architect or engineer involved?: Usually engineers are involved in the strengthening efforts.

What has been the performance of retrofitted buildings of this type in subsequent earthquakes?: Good seismic performance: parapets resist overturning forces and cracking effects were reduced in non structural walls.

Harmsen T. y Mayorca, 1997, de Estructuras de Concreto Armado, Pontificia Universidad Catolica del Peru.

—- Norma Peruana de Albanileria E-070, 1998, Capitulo Peruano del ACI.

Norma Peruana de Sismorresistente E-070, 1998, Capitulo Peruano del ACI.

Quiun, San Bartolome, Torrealva, Zegarra, 1997, El Terremoto de Nasca del 12 de Noviembre de 1996, Pontificia Universidad Catolica del Peru.

San Bartolome, 1994, Construcciones en Albanileria, Pontificia Universidad Catolica del Peru.

San Bartolome, Munoz, Rodriguez, 2001, Fuerzas as de para Edificaciones de Albanileria, Pontificia Universidad Catolica del Peru.