Earthquake Resistance Structure
Abstract
Unexpected disasters events such as, earthquakes are known to have a huge potential for disastrous impact on human life. Earthquakes creates pressure that demolish or collapses buildings, collapsing buildings causes a huge damage on human life and a massive loss economically. During an earthquakes ground vibration could cause an inertia forces on a building which will travel through the rooftop and walls directly to the foundation. Earthquake in known as a phenomenon, but the most damage on human life and nature when a buildings collapse. Collapsing buildings cause 2.1 billion dollars in damage and 10,000 deaths per a year. As a result, according to The Guardian News a massive 7.1 earthquake magnitude shook Mexico’s capital which caused more than 200 deaths which were not from the original movement of the ground, but from collapsing buildings. Building an earthquake resistance building structure that’s designed to resist the effect of earthquake. To create an earthquake resistant building, the structure should be reinforced and counteract to an earthquake’s forces. As known that earthquakes reveal energy that thrusts on a building from one direction, the technique is to have a building that counters the earthquake forces by pushing it to the opposite direction of an earthquake waves. In any case, during an extremely solid earthquake, even the best designed structure may endure serious harm. Specialists plan structures to withstand however much sideways movement as could reasonably be expected so as to limit harm to the structure. Building materials of the earthquake resistance structure has a huge impact on making an earthquake resistance structure building. The materials should have a high ductility to resist vibration and stress. Most structures use steel and wood, a steel that comes in a different shape that allow buildings to bend without collapsing. Wood also has an acceptable ductile material due the high strength relative to the lightweight structure. Furthermore, potential materials used for more flexibility and shape confinement. This essay will focus on different types of solution for collapsing buildings in the duration of an earthquake is to build an earthquake resistance building structure for protection also its strengths and weaknesses and some examples of buildings that has an earthquake resistance structure.
The history of earthquake resistance structure
Create a flexible foundation
Creating a flexible foundation is a way to resist ground movement. Generally, flexible pads isolation underneath the building that keeps the building stay still, so when an earthquake forces hits the ground only the base that has a flexible foundation moves while the structure remains steady. Usually, a building involves a base isolation constructed on top of the flexible pads that are made from rubber, steel and lead to resist the earthquake forces. During the earthquake vibration building structure only oscillate horizontally in a slow cycle. Therefore, damage to people, collapsing buildings, and internal contents can be prevented comprehensively.
(figure 1) This figure shows the different between a normal building structure and a base isolation building structure. https://stock.adobe.com/search?k=aseismic&asset_id=115681816
Counter Forces with damping:
Using dampers to improve earthquake resistance structure. Damping is very significant because this huge measure of an earthquake vitality went into the structure could be made scattered through this instrument along these lines forestalling the basic framework. Lately, the vibration of the structure stops, the lesser will be the harm. Intrinsically, strengthened solid structures have low damping esteem. Improved damping esteem secures the auxiliary framework. Damping qualities of a structure could be improved by the option of extra damping gadgets, Dampers at the key areas inside the structure; which could be the compelling answer for disseminating quake incited powers. Basically, dampers transfer the vibrational energy to thermal energy to prevent the main structure from earthquake induced energy. There are many types for damping a structure such as, viscous elastic dampers, viscous fluid dampers and Friction dampers. A vibration reducing mechanism of viscous elastic dampers is brought into reticulated shells. A limited component examination program of the vibration reducing framework for reticular shells with viscous elastic dampers has improved. Numerical estimations of vibration reducing for single-layer reticulated arches and vaults by the program are completed. It is demonstrated by numerical results that the vibration reducing mechanism of viscous elastic dampers is appropriate to reticulated shells, moreover, viscous elastic dampers has a great vibration decreasing effects. Secondly, the viscous fluid dampers dissipate the force of the vibration. Viscous fluid dampers consist a cylinder that is filled with a viscous fluid and each cylinder has a piston head, so when an earthquake hits the structure of the building vibration energy will be transferred into the pistons to transform heat from the energy of the piston while the piston thrusts against the viscous fluid. Mostly, viscous fluid dampers are located at each story of the building between a column and a beam. Lastly, the friction dampers in other words pendulum. Pendulum structure is a large weighted ball with steel cables that has a hydraulics system on the top of the building, so when an earthquake occurs the ball will react as a pendulum and counters the movement of the earthquake to stabilize the building. Basically, friction dampers are tuned to match and counteract the building frequency when an earthquake hits the ground. (Figure 2) show the three structures of damping.
(Figure 2) this is the three types of damping structures that reduces earthquake waves.
http://www.ergreenman.com/studentpages/2010/disaster3wb.html
Shear walls structure:
Shear walls is a vertical system made from reinforced concrete framed that resists lateral forces such as wind forces. Usually, shear walls designed for high buildings, if the structure increases in height the effect of the wind forces increases significantly. Also, shear walls mostly located around the core of the building which is the internal walls or external walls of the lift shafts and stairwells to provide rigid that is linked to a flexible frame. Generally, shear walls are either designed in a plan or flanged shape to create a channel sections for the core walls. Normally the walls support the columns that connects to a transfer beam to provide clear space for some cases where the lateral loads are kindly small as shown in (figure 3).
(figure 3) This figure shows how transfer beam provides clear space to the foundation. https://theconstructor.org/structural-engg/shear-walls-structural-forms-positioning/6235/
Shear walls are normally intended to show a pliable conduct (Synge et al., 1980; Paulay et al., 1982) by guaranteeing a definitive shear quality being higher than the shear comparing to create flexural yielding in the vertical boundary reinforcement of the walls. Buildings made by shear walls showed quite superior performances during strong earthquakes, such as the ones which stroke Chile on March 3rd, 1985 (Wood, 1991) and February 27th, 2010 (Carpenter et al., 2011).
Examples of buildings:
conclusion:
