Masonry – Page 6 – World Housing Encyclopedia

August 18, 2011December 30, 2011

Report # 12 : Clay brick/concrete block masonry walls with concrete floors (predating seismic codes or with a few seismic features)

by Luis G. Mejia

Typical multi-family housing construction found in urban areas of Colombia. It is a modern construction practice and represents approximately 50% of the housing stock for medium-rise (4- to 6-story high) buildings constructed in the last 25 years. This type of construction generally predates seismic codes; however, some buildings of this type were constructed after the first edition of the Colombian Seismic Code was issued in 1984. This type of construction can be found either on flat or on sloped terrain; vertical stiffness irregularity in the sloped terrain conditions may introduce additional unfavorable effects. Due to poor construction practices and poor detailing of the reinforcement, this construction is considered to be very vulnerable to earthquake effects.

PDF

August 16, 2011December 30, 2011

Report # 11 : Gravity Concrete Frame Buildings (Predating Seismic Codes)

by Luis G. Mejia

This is typical multi-family housing construction found in urban areas of Colombia that predates seismic codes. This housing type is widely used and represents 60% of the existing housing stock. At the present time, poor people occupy buildings of this type. This construction is rather vulnerable to seismic effects due to a limited amount of transverse reinforcement (ties); this is especially true for columns. This structural system is very flexible when subjected to lateral seismic loads. The quality of materials and workmanship is typically rather poor. In many cases, buildings of this type are constructed on a very steep terrain; soil condition is often rather poor.

PDF

August 16, 2011December 30, 2011

Report # 10 : Non-engineered Unreinforced Brick Masonry Building

by Luis G. Mejia

This type of housing is typically constructed in urban and rural areas in the interior of Colombia. This type of construction is especially widespread in the following provinces of the Andean region of Colombia: Antioquia, Caldas, Risaralda, Quindio, Tolima and Valle, where it constitutes approximately 60% of the housing stock. It is used exclusively as residential housing. This construction is very vulnerable to earthquake effects due to its brittle behavior. It has demonstrated poor seismic performance in several Colombian earthquakes.

PDF

August 16, 2011October 31, 2011

Report # 8 : Buildings with hybrid masonry walls

by Ofelia Moroni, Cristian Gomez, Maximiliano Astroza

This housing type represents a common multi-family urban construction in Chile. Practice of this construction “mainly used for dwellings and for up to 4-story apartment buildings” began in the 1980s. The main load-bearing system consists of masonry walls in the transverse direction and reinforced concrete walls in the longitudinal direction. In some cases, longitudinal walls are of reinforced masonry construction (instead of concrete construction). Masonry walls in the transverse direction are usually confined with concrete posts at the ends (such as is found in confined masonry construction). Buildings are usually regular in plan and in elevation. The seismic design code does not address this building type. However, the Chilean Ministry of Housing has issued specifications for 1- and 2-story dwellings, which have mainly been followed in the design (even in taller buildings of this type). Performance in the 1985 Llolleo earthquake was rather poor, with most buildings experiencing structural damage.

PDF

August 16, 2011December 30, 2011

Report # 7 : Confined block masonry building

by Ofelia Moroni, Cristian Gomez, Maximiliano Astroza

This construction practice started during the 1940s after the 1939 earthquake that struck the mid-southern region of Chile. It is mainly used for dwellings and apartment buildings up to four stories high. Buildings of this type are found in all regions of Chile. This is a confined masonry construction, consisting of load-bearing unreinforced masonry walls (commonly made of clay units or concrete blocks) confined with cast-in-place reinforced-concrete, vertical tie-columns. these tie-columns are built at regular intervals and are connected with reinforced concrete tie- beams cast after the masonry walls have been constructed. Tie-columns and tie-beams prevent damage due to out-of-plane bending effects and improve wall ductility. Floor systems generally consist of cast-in-place reinforced slabs with a thickness between 100 to 120 mm. Confined masonry walls have limited shear strength and ductility compared to reinforced concrete walls. Nevertheless, typical buildings of this type have good earthquake resistance, because they have high wall densities and because wall layouts are symmetric and regular, both in plan and elevation. Their seismic behavior has been satisfactory, particularly in one- or two-story-high buildings during strong earthquakes [Monge, 1969].

| PDF

August 15, 2011October 31, 2011

Report # 5 : Reinforced Clay/Concrete Block Masonry Building

by Ofelia Moroni, Cristian Gomez, Maximiliano Astroza

This is a rather recent construction practice followed since 1970, and it has been widely used for dwellings and up to 4-story-high apartment buildings. Buildings of this type can be found both in urban and rural areas of Chile. The main load-bearing elements are masonry walls reinforced with vertical steel reinforcement bars and placed in the hollow cores of clay masonry units (hollow clay tiles) or concrete blocks. Horizontal reinforcement bars are placed in horizontal bed joints. Masonry shear walls are tied together at floor levels by means of reinforced concrete beams in a regular structural layout. Stiffness distribution both in plan and elevation is uniform. Prior to 1986, there was no seismic design code for this structural type. During the March 3, 1985 Llolleo earthquake, performance of buildings of this type was rather poor, mainly due to construction problems, such as partial grouting in the hollow cores with reinforcement, poor quality of the mortar, and lack of horizontal reinforcement. Following the earthquake, the Chilean Design Code NCh1928 code was published based on the U.S. Uniform Building Code (UBC-1979) and on the seismic performance of this construction type reported in previous earthquakes. Since 1993, when the last version of NCh1928 was published, and more restricted requirements were enforced, the use of this type of construction has been less frequent, in part because of economic reasons.

PDF

August 15, 2011October 31, 2011

Report # 1 : Confined Block Masonry House

by Virginia I. Rodriguez, Maria I. Yacante, Sergio Reiloba

This is typically a one-or two-story residential building of detached or semi-detached construction, generally found in the urban areas of San Juan and Mendoza, and less frequently in the rural areas. The walls are made of concrete block masonry with reinforced concrete columns and beams that tie the walls together and provide strength for the building. One of the main structural deficiencies for this construction type lies in the widely different wall densities in the two orthogonal directions. This deficiency may be eliminated with appropriate architectural design. This construction type is otherwise expected to demonstrate good seismic performance.

PDF