Category: Asia & Mideast

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Report # 66 : Precast reinforced concrete frame panel system of seria IIS-04

by Shamil Khakimov, Bakhtiar Nurtaev

This housing type is used in the construction of residential and public buildings in many cities throughout Uzbekistan (including the capital city Tashkent) that are located in zones with intensities between 7-9. Residential buildings of this type are generally 9 to 12 stories high, whereas public buildings of the same construction are 1 to 4 stories high. All seismic load-resisting (and also nonstructural) components, e.g., foundations, columns, girders, slabs, staircases, wall panels, etc., are manufactured in specialized plants. The materials are subsequently transported to the building site. The positive features of this construction type are (1) the ability to manufacture all building materials in an industrialized setting, and (2) the gain in efficiency inasmuch as the same building components may be used both for residential and public buildings. The key drawback is that the welded joints cause seismic vulnerability when the building is located in zones of extremely high seismic loads. These joints have shown extremely brittle behavior during earthquakes. Earthquake damage is mainly concentrated in the column joints, or in the column-to-girder joints. In some cases non-bearing walls and exterior wall panels have collapsed.

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Report # 63 : High-rise, reinforced concrete buildings with open space at the ground floor

by Su C. Tung, George C. Yao


This is an urban housing construction. Typically, these are 12-story apartment buildings with a parking area in the basement. The first and second floor are classified as Open Space (OS) and the ground floor is used by the residents for gardening and for leisure and social gatherings. The common features in these buildings are: (1) The two lower floors were designed for the OS with a net height of approximately 7.6 meters. (2) There are many walls above the third floor in both horizontal directions but very few walls on the OS except around the elevator shaft and the staircases. If the elevator is located at the corner of the building, torsional effect may be present. (3) Architects tend to design zigzag floor plans for these buildings in order to maximize view angle and natural lighting. (4) Very few columns were designed into these buildings in order to maximize the parking area on the basement level. The primary load-resisting system is reinforced concrete moment-resisting frame on a mat foundation. The fact that the partition walls are dense at the third floor and above, creates a soft-story configuration in the lateral load-resisting system. Many buildings of this type collapsed in the 1999 Chi-Chi earthquake due to the soft-story effect caused by the OS design

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Report # 62 : Street front building with arcade at the first floor (contemporary construction)

by George C. Yao, M. S. Sheu

This building type is common in many Taiwanese cities and towns. The street-front buildings are medium-rise, reinforced concrete frames with infill brick masonry walls serving as partitions. Usually, the first floor (typically 4 m high) is used for commercial purposes while the upper stories (typically 2 to 4 stories above, floor height 3 m) are used for storage and residences. Neighboring units of similar design have been constructed together to form a corridor for pedestrians to walk in. Connected units vary in number from 6 to 10 and they may be built in a row, in an L shape, or in the U shape. There are several structural deficiencies associated with this building type: (1) the weak and soft first story can result from a large opening at the street level for commercial use; (2) a typical building layout has walls in one direction only, perpendicular to the street; as a consequence, there are few earthquake-resisting elements in the other direction; (3) extra rooftop additions increase loads. Also, building owners tend to reduce the number of columns for a wider storefront view. Many buildings of this type collapsed in the Chi-Chi earthquake of 1999

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Report # 61 : Street front building with arcade at the first floor (pre-1970’s construction)

by George C. Yao, M. S. Sheu

This building type is common in most Taiwanese cities and towns. It represents a construction practice that was followed before1970 and is no longer used. The main load-bearing structure consists of reinforced concrete frames designed for gravity loads only, with brick masonry infill walls. Brick walls were built before the concrete was poured thereby serving as a formwork for concrete. Buildings of pre-1970 construction were characterized with a better bond between the masonry and concrete as compared to the buildings of more recent construction, in which reinforced concrete frames serve as main load-bearing system for lateral and gravity loads. Buildings of this type are medium-rise (4 to 5 stories high). Usually, the first floor (typically 4 m high) is used for commercial purposes while the upper stories (typically 2 to 4 stories above, floor height 3 m) are used for storage and residences. Neighboring units of similar design are constructed together to form a shady corridor for pedestrians to walk in. The number of connected units varies from 6 to 10. These units may be connected in one row, or in an L shape, or in the U shape along the street block. There are several structural deficiencies characteristic for this construction: (1) the weak and soft first story because the commercial space demands a large opening at the street level; (2) typical building layout has walls in one direction only, perpendicular to the street. As a consequence, there are few earthquake-resisting elements in the other direction; (3) extra rooftop additions increase the load. Many buildings of this type collapsed in the 1999 Chi-Chi earthquake.

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Report # 59 : Reinforced concrete frame with concrete shear walls – dual system

by Adel Awad, Hwaija Bassam, Isreb Talal

These buildings are characterized by a combination of shear walls and frames in both directions. The buildings are multiple housing units found in the main cities of Syria. The shear walls are often part of the elevator and service cores, whereas the frames are arranged in-plane, in conjunction with the walls, to support the floor system. Stiffness and mass distribution are irregular and the majority of buildings may experience soft-story or torsional problems. As a result, these buildings are expected to have only moderate seismic resistance.

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Report # 49 : Unreinforced concrete and masonry bearing wall construction (designed for gravity loads only)

by Jalal N. Al Dabbeek, Abdel H. W. Al-Jawhari

This building type is usually found in most cities of the West Bank and less often in the Gaza Strip. It is a traditional, non-engineered, low-rise construction practice. The main lateral load-resisting system consists of bearing walls with unreinforced concrete strip foundation. The interior masonry walls consist of plain concrete (system #2) or two wythe stone masonry walls filled with plain concrete (system #1). The exterior bearing walls consist of stone masonry facing with a plain concrete backup. Wall thickness ranges from 400 to 500 mm (system #1) to 300-mm thickness in system #2. It is important to note that system #1 represents the old practice for bearing-wall construction while system #2 represents the new trend which was developed and used from the 1950s to the 1970s. This construction is not practiced at the present time.

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Report # 48 : Reinforced concrete frame with infill walls designed for gravity loading

by Jalal N. Al Dabbeek, Abdel H. W. Al-Jawhari

This building type is usually found in most cities of West Bank and less often in the Gaza Strip. The structural system consists of solid slabs (either one-way or two-way) with beams and columns. The columns are usually of rectangular cross-section. The beams may be either dropped (deep) or hidden. The infill walls in the external frames may consist of stone with plain concrete only, or stone with plain concrete and hollow block. Sometimes polystyrene of 2-cm thickness is added for isolation purposes. On the other hand, the internal infill walls consist only of concrete hollow blocks of 10 cm thickness but may be as thick as 15 or 20 cm. These walls are used and considered as partitions.

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Report # 47 : Traditional oval-shaped rural stone house

by Yogeshwar K. Parajuli, Jitendra K Bothara, Bijay K. Upadhyay

This is a typical rural construction concentrated in the central mid-mountain region, particularly in the Kaski, Syangja, Parbat, and Baglung districts. (The country is divided into 75 administrative districts.) These primarily residential buildings are basically loose-fitting, load-bearing structures, constructed of uncoursed rubble stone masonry walls and a timber structure for the floor and roof. Village artisans play a pivotal role in these owner-built buildings. Because of the loss of integrity during an event, they are expected to be extremely vulnerable from the effects of an earthquake.

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