Safety Building in Earthquake Zone - Essay Example

Safety Building in Earthquake zones Author Course Tutor Date Introduction An Earthquake arises due to the shifting and breaking of rocks below the earth surface. It is an immediate speedy shaking of the earth. Stress develops beneath the surface of the Earth for a considerably long time, which eventually erupts causing an Earthquake. The shaking may last for hours or weeks depending on its magnitude. Earthquakes cause serious damage in built-up areas, and this could lead to lose of life and property. Every person has the duty to protect their homes from the effects of Earthquakes. Since it is difficult to predict with certainty the time an earthquake will occur, it is prudent for construction companies to take precaution when establishing buildings in Earthquake zones (Tucker, 2004). This paper focuses on the how to ensure safety of buildings in Earthquake zones and the requirements needed in the construction of such structures. Protecting buildings from Earthquakes The complexity of buildings in respect to their dynamic characteristics requires application of safety measures. Buildings in Earthquake zones are prone to damage and therefore they need to be protected from the risk (Nawrotzki, 2000). As a result, construction companies use the conventional seismic design which prevents buildings from collapsing when exposed to strong earthquake. The building can only sustain damage on elements that are not constructed like glass facades, and not total destruction. According to Murty (2005) two technologies are used to protect buildings from the effects of earthquake, and they include Base Isolation and Seismic Dampers. Base Isolation This technology involves isolating the building from the ground in a manner that the motions of the earthquake don’t go through the building, or are reduced. This reduces the effect of the earthquake to the building. The effect of base isolation can be well explained by considering a building that rests on the frictionless rollers. In case an earthquake occurs, the rollers will move freely without affecting the rest of the building. This means that the building will not experience the earthquake. A building that rests on well fixed flexible pads (base isolators) exposes the building to lesser shaking than a building established directly on the ground. The base isolation technology is preferred in protecting buildings from earthquakes because it initiates flexibility in the building (Murty, 2005). The isolators are made in a way that they are able to absorb energy, which adds damping to the entire system. This reduces the effects of seismic response further, and thus protecting the building. Seismic Dampers This approach is use to control the seismic damage that occurs in buildings during earthquakes. Protecting buildings from effects of earthquakes is done by using seismic dampers instead of building elements like diagonal braces. The seismic dampers perform as the hydraulic shock absorbers in vehicles. When an earthquake occurs and transmits the seismic energy through these dampers, they absorb part of the energy reducing the motion in the building. Since 1960s, dampers were used to guard building against the effects of wind, but they are now used to protect building against earthquakes (Murty (2005). Nawrotzki (2000) argues that in order to utilize seismic control systems in buildings, the damping should be increased. The dampers are used to reduce frequency of shaking when an earthquake occurs, and this reduces the effects of earthquakes in the building. Technical aspects in earthquake resistant buildings According to Brzev (2007) buildings are able to resist effects of earthquakes depending on the design and materials used to built them. Depending on the type of building and the location, some resistant features to earthquake are required in buildings. The factors that influence seismic resistance in building located in earthquake areas include their wall density, Masonry units and motor, tie-columns, horizontal wall reinforcement and openings. Wall density is an important aspect that helps to protect buildings from effects of earthquake. Wall density is arrived at by dividing the total area of walls in every direction by the total area of the building floor. The walls density in each direction of building in earthquake areas is normally high, close to 10%. Such buildings sustain light damage in case an earthquake occurs. The load resistance of the walls of buildings depends on how strong the units and mortar are installed. Buildings in the earthquake prone zones are built using solid blocks units which gives them strength to resist pressure. When buildings are constructed by use of grouted and solid units the mass of their walls and seismic load increases which offers them more protection to effects of earthquakes. The tie columns also determine the ductility and stability of the walls of building especially when they develop cracks. The transverse reinforcement in the buildings are closely spaced both at the top and bottom of the tie columns. This helps to improve the ductility and stability of the wall and the entire building during the time of an earthquake (Brzev, 2007). Horizontal wall reinforcement is an aspect considered when building is earthquake zones. Horizontal joint reinforcement in form of wires is put in the joints of mortar bed to help the building withstand shaking. The building has horizontal bars which are fixed in the tie-columns, and this increases the ductility of the wall fiving the building stability and strength. Research indicates that an opening area which is less than 10% of the entire wall area does not offer adequate protection to the building compared to solid walls. Buildings in earthquake zones are built with very few opening to limit the effect of earthquake shakes (Brzev, 2007). The openings of windows on such buildings are estimated considering the net transverse area of the wall of the building. Safety procedures Establishing buildings in earthquake zones should be done by considering the safety requirements. Earthquake safety programs have been designed to ensure safety of buildings is maintained, and to reduce the effects of earthquakes. The earthquake safety programs include seismic safety policy, accountability, building codes, training and qualification, and the element of planning and preparedness among others. Seismic safety policy should be created by law, indicating objectives that are clearly defined and measurable. It should receive adequate support and be enforced by the government authorities. The purpose for developing this policy is to ensure safety in the building environment. The element of accountability entails holding the responsible the members of the society who are in charge of implementation of the earthquake safety programs. They should make sure that buildings in earthquake zones meet the required standards. Holding them accountable instills discipline in their actions, especially when developing buildings which helps to reduce risks of safety (Tucker, 2004). Tucker (2004) argues that the building codes and regulations are meant to protect the life of people occupying buildings in earthquake zones. These codes should oversee the plan of both the new and retrofitted buildings. The earthquake ground motions are established by use of probabilistic analysis, or based on seismic zone maps. The main objective of the building codes is to determine the suitable design criteria that meet the requirements of safety. Safety in building depends on laws and regulations that need appropriate training of the construction professionals. Building in earthquake areas by use of qualified construction professional helps to reduce the risks associated with the shaking of the ground. Preparing and planning prior to earthquake eruption is important to prevent severe damage. This involves educating the community how to react safely at the time of emergency. Safety assessments could also be conducted as a way of preparing for future earthquakes. Materials used According to Haseeb et al (2011) earthquake resistant buildings are built considering the seismic code and the building codes to ensure the safety of the building. The building materials used in earthquake areas depends of their availability. In some earthquake zones, buildings are constructed using bricks as the basic material for construction. Such buildings are resistant to strong earthquakes. Timber is also used in building to provide complete skeletal framing. If well engineered, timbers offer seismic survivability in the structure. In some areas where there are earthquakes, buildings are made from concrete. In order to prevent severe damage, concrete structures are built with ductile joints, which are reinforced with steel bars to give the building strength. However, in mountain areas where the terrain is poor, the basic materials for building are stones. Light stonework is encouraged so as to increase the durability of the buildings in such areas. Conclusion Conclusively, establishing buildings in earthquake zones requires a lot of care as far as safety is concerned. Earthquake is a dangerous and lead to destruction of property and loss of life. As discussed above, there is need to protect buildings from the effects of earthquake, and this is done at the time of building. The most appropriate ways is the use of Base Isolation technique and the Seismic dampers during the construction. These reduce the impact of earthquake on the building, thus offering adequate protection. The paper further identified that buildings in earthquake areas have high wall density, horizontal wall reinforcements, and few openings among others. Seismic safety policy is one of the safety procedure adopted by the construction companies who build in earthquake zones. Finally, the paper illustrated that bricks, timber, steel and concrete are the building materials used in building in earthquake areas, but it depends on the location. References Brzev, S 2007 “Earthquake-resistant confined masonry construction”, NICEE, National Information Center of Earthquake Engineering, Indian Institute of Technology Kanpur. Haseeb, M., Xinhailu, A. B., Khan, J. Z., Ahmad, I., & Malik, R 2011 “Construction of earthquake resistant buildings and infrastructure implementing seismic design and building code in northern Pakistan 2005 earthquake affected area”, International Journal of Business and Social Science, 3(2), pp:168-177. Murty, C. V. R 2005 “Earthquake Tips: Learning Earthquake Design and Construction”, National Information Center of Earthquake Engineering, Indian Institute of Technology Kanpur. Nawrotzki, P 2000 “Earthquake Protection for Buildings and other Structures”. Tucker, B. E 2004 “Trends in global urban earthquake risk: a call to the international Earth Science and Earthquake Engineering communities”, Seismological Research Letters, 75(6), pp:695-700. Read More

Technical aspects in earthquake resistant buildings According to Brzev (2007) buildings are able to resist effects of earthquakes depending on the design and materials used to built them. Depending on the type of building and the location, some resistant features to earthquake are required in buildings. The factors that influence seismic resistance in building located in earthquake areas include their wall density, Masonry units and motor, tie-columns, horizontal wall reinforcement and openings.

Wall density is an important aspect that helps to protect buildings from effects of earthquake. Wall density is arrived at by dividing the total area of walls in every direction by the total area of the building floor. The walls density in each direction of building in earthquake areas is normally high, close to 10%. Such buildings sustain light damage in case an earthquake occurs. The load resistance of the walls of buildings depends on how strong the units and mortar are installed. Buildings in the earthquake prone zones are built using solid blocks units which gives them strength to resist pressure.

When buildings are constructed by use of grouted and solid units the mass of their walls and seismic load increases which offers them more protection to effects of earthquakes. The tie columns also determine the ductility and stability of the walls of building especially when they develop cracks. The transverse reinforcement in the buildings are closely spaced both at the top and bottom of the tie columns. This helps to improve the ductility and stability of the wall and the entire building during the time of an earthquake (Brzev, 2007).

Horizontal wall reinforcement is an aspect considered when building is earthquake zones. Horizontal joint reinforcement in form of wires is put in the joints of mortar bed to help the building withstand shaking. The building has horizontal bars which are fixed in the tie-columns, and this increases the ductility of the wall fiving the building stability and strength. Research indicates that an opening area which is less than 10% of the entire wall area does not offer adequate protection to the building compared to solid walls.

Buildings in earthquake zones are built with very few opening to limit the effect of earthquake shakes (Brzev, 2007). The openings of windows on such buildings are estimated considering the net transverse area of the wall of the building. Safety procedures Establishing buildings in earthquake zones should be done by considering the safety requirements. Earthquake safety programs have been designed to ensure safety of buildings is maintained, and to reduce the effects of earthquakes. The earthquake safety programs include seismic safety policy, accountability, building codes, training and qualification, and the element of planning and preparedness among others.

Seismic safety policy should be created by law, indicating objectives that are clearly defined and measurable. It should receive adequate support and be enforced by the government authorities. The purpose for developing this policy is to ensure safety in the building environment. The element of accountability entails holding the responsible the members of the society who are in charge of implementation of the earthquake safety programs. They should make sure that buildings in earthquake zones meet the required standards.

Holding them accountable instills discipline in their actions, especially when developing buildings which helps to reduce risks of safety (Tucker, 2004). Tucker (2004) argues that the building codes and regulations are meant to protect the life of people occupying buildings in earthquake zones. These codes should oversee the plan of both the new and retrofitted buildings. The earthquake ground motions are established by use of probabilistic analysis, or based on seismic zone maps. The main objective of the building codes is to determine the suitable design criteria that meet the requirements of safety.

Safety in building depends on laws and regulations that need appropriate training of the construction professionals.

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