Saturday, September 15, 2012

home remodeling - how to improve the post-earthquake

home remodeling - how to improve the post-earthquake - In the last five years, the coastal areas of West Sumatra has several times experienced the earthquake with strong intensity. Starting from the earthquake in Aceh December 26, 2004 until 30 September 2009 earthquake Pariaman ago. The last earthquake measuring 7.9 on the Richter scale killed more than 1,000 people and damaging 279,432 buildings, with 50 percent of them were severely damaged.

Most of the building was heavily damaged, but not destroyed. To handle the heavy damaged buildings, building demolition is the alternative most often taken. This is wrong. Not all of the buildings damaged by the earthquake should be torn down. Structural analysis needs to be done before the building was decided to be torn down. In fact, many of these buildings that just need to be improved and strengthened only in the parts that are broken, without having to be torn down.

Many who do not know, actually there is a science to evaluate buildings damaged by the earthquake. This science can identify the damaged part and contributing factors, such as due to gravity, compressive force and shear forces on the parts of the building were damaged. In addition, software is available to support these activities, so that the damage can be identified, whether it is in the structure of the building, as well as damage to the walls of the building.

Another alternative that is better than doing the destruction is to retrofit. In general, the retrofit can be described as the addition of new technologies Atua merger between the new technology on the old system (which already exists). In other words, the retrofit is the process of retrofitting old buildings with the aim of making the building resistant to earthquakes. Using this knowledge will save costs and more efficient use of labor.

In general, damage to multistory buildings are of two types. When built with the execution was pretty good, but less powerful, it is usually damage to the ground floor of the building. However if the implementation is not good, then the damage usually occurs in the upper floor of the building. But besides that, there are some other typical damage is common, such as a sagging roof, the walls split at the meeting of two walls, the destruction of the wall corners, wall cracks at the corners of openings, diagonal cracking walls, the walls collapsed, the failure of the connection between beam to the column, and the fall of the building itself.

Among tipihal damage described above, some of which can be improved and strengthened. To repair a cracked wall is small (with a gap width of less than 5 mm), can be reached by way of peeling plaster about 50 cm long around the broken wall, then fill it with water or chemical cement (epoxy). After the meeting a gap, re-plastered walls with a mixture of 1 cement: 3 sand.

While for large cracks (cracks that have a slit width greater than 5 mm), the old plaster around the crack peeled (minimum 50 cm), and crack filled with mortar 1 cement: 3 sand or chemicals. Once the crack is closed, make pleseran kepalaan 1 cm, width + 2 cm which serves as a place holder wire mesh. Then, installed wire mesh on both sides of the wall in a way tied to one another. Next, re-plastered walls with campura species 1 cement: 3 sand.

To repair concrete columns and beams were damaged also classified according to the type of damage. There are several types of damage to the concrete columns and beams. For cracks in the concrete that is less than 0.2 mm or cracks not visible indicate no significant damage. Generally cracks in the concrete component widths up to 2 mm are not considered dangerous and indicate corresponding minor damage. Apda cracked concrete component with a width of up to 5 mm indicates moderate damage. Cracks in the concrete component with a width greater than 5 mm mengndikasikan heavy damage (with a significant reduction in force). Tertekuknya reinforcement in concrete components indicate severe damage, with no regard to the width of cracked concrete. But the damage is the destruction of common columns and beams at the connection between the beam column.

Generally, techniques for strengthening columns / beams benton is 1) Increase the number of rebars and stirrups outside the column / beam concrete, then covered again with a new concrete mix. 2) Envelop columns / beams with reinforced concrete that has been fabricated (welded wire fabric) and then covered with mortar. 3) enveloping concrete columns with square steel profiles or pipes, and then grouting the cracks between the concrete and steel. 4) Install the bandage from steel plates welded to the steel profiles elbow mounted on each corner of the column, and then grouting the gaps.

It described above is only a fraction of the ways repair / retrofit that can be implemented into the story buildings damaged. For further information, can be obtained at the office of Construction Clinic Andalas University Centre for Disaster Studies, Jalan Ahmad Yani No.. 12 Padang

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