Report # 31 : Brick masonry farmhouse with a “dead door”

by Agostino Goretti, Daniela Malvolti, Simona Papa

This is a single-family farmhouse construction, found throughout the Padania plain (Reggio Emilia Province). This housing type accounts for approximately 20% of the entire housing stock in the Reggio Emilia municipality. This building practice is no longer followed. Most of the existing buildings were built in the 19th and 20th centuries. The residential and agricultural sections of the house are separated by a central area closed at one end and hence called a “dead door.” The residential section usually has two floors (typical story height 2.5 – 3.0 m) and a sloping roof. The agricultural portion, usually larger than the residential section, also has two floor levels. The first-floor height is on the order of 2.5 – 3.0 m whereas the second-story floor height ranges from 5.0 – 9.0 m. As a result, the roof in the agricultural section of the building is at a higher level than that of the residential. The first floor is used as a cow shed and the second as a hayloft. The load-bearing structure consists of brick masonry walls in lime mortar. The walls are characterized by variable thickness, decreasing from 280 mm at the first-floor level to 150 mm at the second-floor level. There are brick masonry columns in the interior of the agricultural section at the second-floor level. The buttresses can be found in the exterior brick masonry walls. Both the residential and agricultural sections have wooden floors; there are vaulted floors in the central area. In some cases, composite floors made of steel beams and perforated bricks can be found. Although the building plan is very regular, the seismic performance of this building type is rather poor due to the vertical irregularity (offset of the floors in the residential and agricultural sections), the absence of connections between walls and between the walls and floors, the thrusting of the roof, and the deterioration of materials.

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Report # 29 : Single-family historic brick masonry house (Casa unifamiliare in centro storico, Centro Italia)

by Dina D’Ayala, Elena Speranza, Francesco D’Ercole

This single-family housing type, found throughout the Central Italy (Centro Italia) mainly in hill towns and small cities, is typically built on sloped terrain. A typical house is 3 stories high, built between two adjacent buildings with which it shares common walls. The main facade of the house faces a narrow road. The ground floor level (perforated with openings on one side only) is used for storage, while the other two stories are used for residential purposes. Typical buildings of this type are approximately 3 m wide and 9 m long. The building height on the front side is on the order of 4.5 m, whereas the height on the rear side is larger (close to 5 m). All the walls are made of unreinforced brick masonry in lime mortar, while the floor structures are vaults at the ground floor level, and timber floor structures at the higher levels. The roof is made of timber and is double-pitched, sloping down towards the front and rear walls. Buildings of this type are expected to demonstrate rather good seismic performance, mostly due to their modest height. Problems related to seismic performance might be caused by the adjacent buildings (typically one story higher). Seismic strengthening techniques for buildings of this type are well established and strengthening of some buildings has been done after the recent earthquake.

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Report # 28 : Single-family stone masonry house

by Dina D’Ayala, Elena Speranza

These buildings form the historic centers of most hilltop villages and towns in central Italy. They are arranged in long terraced clusters. Hillside dwellings have common walls and a variable number of stories (up to 2 or 3). Buildings situated in the valley usually have 4 or 5, with a maximum of 6, stories. The typical house is usually formed by one or two masonry cells, depending on the depth of the block, and with a staircase (usually but not necessarily) running along the common wall. The masonry is made of roughly squared stone blocks set in lime mortar, and the walls are made of two leaves with a rubble core at the base, tapering at the upper floors. Limestone is used for the blocks, while a particular type of tuffa stone is used for the lintels above the openings. At the ground level there are sometimes vaulted structures. The upper stories were originally spanned by timber beams, with joist and timber boards covered by tiles. The roof structure is usually original and made of timber trusses. In the recent past, many of the original floors have been replaced either with iron ‘I’ beams and jack arches (renovations occurring before World War II), or during the last fifty years, with weakly reinforced concrete slabs. Other alterations include vertical extensions, the closing and opening of windows, and introduction of hygienic services. A high proportion of these houses exhibit the traditional iron ties introduced in the 18th century to tie together the orthogonal walls and floors for better seismic performance. After the introduction of modern seismic codes in the 1980s, many buildings have undergone further strengthening through the use of RC ring beams and concrete jacketing of walls.

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Report # 27 : Confined brick masonry building with concrete tie columns and beams

by Behrokh H. Hashemi, Faramarz Alemi, Mohsen G. Ashtiany

This is a typical confined brick masonry housing construction common in rural areas of Iran. This building type is often used as a single-family house. Brick masonry shear walls confined with concrete tie columns and beams provide earthquake resistance in both directions. This building type is expected to have good seismic performance.

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Report # 24 : Unreinforced clay brick masonry house

by Sugeng Wijanto

Unreinforced clay brick masonry (UCB) housing construction is still often found in rural areas of Indonesia. This is a single-story building and the main load-bearing structure in these buildings consists of brick masonry walls built in cement mortar and a timber roof structure. This is non-engineered construction built following the traditional construction practice, without any input by architects or building experts. Builders follow a pattern by observing the behavior of typical buildings in the surrounding area. Buildings of this type typically experience severe damage or collapse in the earthquakes in Indonesia.

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Report # 22 : Unreinforced brick masonry walls with pitched clay tile roof

by Amit Kumar

This is a traditional construction practice followed in India for centuries. Buildings of this construction type are used for residential, commercial, and public purposes throughout India, especially in the northern and central parts, where good quality soil for brick production is widely available. This is a single-story construction used both in rural and urban areas. The walls are constructed using clay bricks laid in mud, brick-lime or cement/sand mortar. The roof does not behave as a rigid diaphragm. These buildings are built without any seismic provisions and are considered to be moderately-to-highly vulnerable to earthquake effects.

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Report # 21 : Unreinforced brick masonry building with reinforced concrete roof slab

by Ravi Sinha, Svetlana N. Brzev

Typical rural and urban construction in western and southern India. This construction is widely prevalent among the middle-class population in urban areas and has become popular in rural areas in the last 30 years. Brick masonry walls in cement mortar function as the main load-bearing element. The roof structure is a cast-in-situ reinforced concrete slab. If constructed without seismic features, buildings of this type are vulnerable to earthquake effects. They exhibited rather poor performance during the Koyna (1967), Killari (1993), Jabalpur (1997), and Bhuj (2001) earthquakes in India.

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Report # 20 : Unreinforced brick masonry walls in mud mortar with flat timber roof

by Amir Ali Khan, Khalid Moin

This is a traditional construction practice prevalent both in the urban and rural areas of northern India, particularly in the western part of the Uttar Pardesh state. According to the 1991 Indian census, this construction constitutes about 17% of the total national housing stock and about 31% of the U.P. housing stock. Typically, this is a single-story construction. The main load-bearing elements are unreinforced brick masonry walls in mud mortar built without any seismic provisions. The roof structure consists of timber beams supported by the walls. Clay tiles or bricks are laid atop the beams; finally, mud overlay is placed on top of the tiles for the thermal protection and to prevent leakage. The main seismic deficiencies are heavy roofs and low-strength masonry walls, which render the building rather vulnerable to seismic effects.

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Report # 18 : Rubble stone masonry walls with timber frame and timber roof

by Svetlana N. Brzev, Marjorie Greene, Ravi Sinha

This typical rural construction in central, southern, and northern India houses millions of people. It is cheap to construct using field stones and boulders, but extremely vulnerable in earthquakes because of its heavy roofs and poorly constructed walls. The load-bearing structure is a traditional timber frame system, known as ‘khan’. It is a complete frame with timber posts spanned at about 2.6 m. Thick stone walls (typical thickness 600 mm – 1.2 m) provide enclosure and partial support to the roof. Walls are either supported by strip footings of uncoursed rubble masonry or are without any footings at all. The roof structure consists of timber planks and joists. To help keep the interiors cooler during hot summer months (peak temperatures exceeding 40°C.), a 500-800 mm thick mud overlay covers the top the roof. This construction type is considered to be very vulnerable to earthquake effects. Many buildings of this type were damaged or collapsed in the 1993 Killari (Maharashtra) earthquake (M 6.4) with over 8,000 deaths.

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Report # 16 : Load-bearing stone masonry building

by T. P. Tassios, Kostas Syrmakezis

These buildings are mainly found in the historical centers of Greek cities and provinces. The main load-bearing structure consists of stone masonry walls. The walls are built using local field stones and lime mortar. The floors and roof are of timber construction. The seismic performance is generally poor. Diagonal cracking at the horizontal and vertical joints are the common type of damage.

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