Tsunami Resisting Structure Design

Tsunami Resisting Structure DesignTsunami moving ridgesAbstractIn the noncurrent Lebanon has experienced some(a) major quakes and tsunamis. Kids are taught at school that Lebanons capital Beirut was buried 9 times because of these catastrophic events. However, separate than manmade disasters, modern situation has been calm and this small Mediterranean country has been tsunami free for quite some time. regrettably studies show that this situation bequeath not remain as calm in the future and that the Lebanese coast is in danger of re-experiencing these curl ups. In this paper the historic Tsunami activity around the universe of discourse result be reviewed and evidence shall be given on why this event leave behind chance on Lebanon later on 1500 years of absence. In addition, the behaviors and characteristics of tsunamis leave alone be presented, how they start and how they destroy and by knowing the effect they go for on buildings and the damages they cause to their elements, we are able to intent a structure with the cast of resisting these loads. The aim of this study is to design a Tsunami Resisting Structure in accordance with the current guidelines and complying with the existing Standards and Codes, that is pass judgment to provide safe refugee from Tsunami and earthquakes. An example shall be given and the applied loads shall be calculated in the following pages.IntroductionIt is said in the bible that the Lord told Noah that a flood of waters shall be brought upon the Earth to destroy mankind, both man and beast shall drown (Genesis 617). Tsunamis subscribe to been dieing since the ascendent of time, in the past as well as in our days when that event occurred, as spell of evacuation technique or simply by instincts for survival people try to escape by going inland or trying to reach higher altitudes. But the wave hits the land with extensive energy and speed that basically trying to race it horizontally is practically impossib le and well-nigh casualties that play during a tsunami is when people try to flee the coast and move inland to higher altitudes. In some areas an evacuation is not possible in time and the best chances people gain is through a steep evacuation by moving upwards to higher levels in a tsunami resisting structure. (FEMA P646A, 2009)The idea of a vertical evacuation structure came to be after the tragic Sumatra earthquake and Indian Ocean tsunami in December 26, 2004. 300,000 lives were lost in the boxing day tsunami (Christian Meinig et al.,2005), and that number would have been so much worsened if Rein enduringnessd Concrete Structure did not act as shelters for survivals. (FEMA P646A, 2009)We learnt from past events, and if a concrete multistorey house was able to resist, even it was temporarily, even if it was for a short term, then a structure squirt be designed to withstand Tsunami as well as earthquakes, because in most cases, these 2 hazards are connected.DefinitionThe Fe deral Emergency Management Agency (FEMA) and the National Oceanic Atmospheric Administration (NOAA) excuse tsunami as A Tsunami is a naturally occurring series of ocean waves resulting from a rapid, oversized-scale disturbance in a body of water.). They can be caused by either volcano eruption under water, or earthquake or landslides etc. (FEMA P646A, 2009). When they travel in the ocean the waves and fast entirely short in tallness, but when they reach the coast, the waves gain in height.It was believed that a number of events led to these oceanic waves however after the study of past events it was concluded that the major cause for tsunami generations was due to tectonic movements. Katsuyuki Abe in his publication Tsunami and appliance of great earthquakes explains the relationship between these waves and earthquakes. Katsuyuki Abe said tsunamis are generated by tectonic deformations rather than by large submarine landslides and slumps. (Katsuyuki Abe, 1972). When tectonic pl ates are active, plate deformation induces seismic activity that cause earthquakes (Stein and Klosko, 2002) and The source of the tsunami/earthquake can be tracked back to its origin by analyzing the arrival date of the first wave to the shore.The boxing day 2004 Tsunami went down in history as the deadliest tsunami, with more than 230,000 casualties across 14 countries The earthquake triggering the tsunami was of magnitude 9, the most powerful earthquake in 40 years (ABC news, 2014). With its epicenter set(p) at the Sumatra coast, between 2 tectonic plates, the Indian plate and the Burma plate. The two plates were so stressed that the earthquake come on when the Indian plate slipped under the Burma plate. (Sudhir et al., 2005)Tsunami in LebanonNo matter where we read or heard it, whether it was in the findings and studies published by the National Council for Scientific Re search, Beirut, Lebanon or National Center for Geophysics, Lebanon or even in the August issue of the journal Geology 2007 or National Geographic intelligence or Discovery News channel or the local newspapers, the context were the same It is just a matter of time onwards a destructive tsunami hits this region.An underwater survey placed Lebanon near an active fault that could generate an earthquake in the seafloor create a devastating tsunami in the region. Elias Ata and colleagues researched that the same fault that was responsible for the strongest earthquakes in the Mediterranean is active and is in danger of producing a tsunami wave just like it did thousands of years ago in the 551 A.D. tsunami in Phenecia now known as Lebanon (Elias et al, 2007). They confirmed the presence of fresh seismic breaks in the sea floor and argued that the Mount Lebanon thrust is identified as repeated earthquakes with 1500 years of return. Since the last earthquake was in 551 A.D. with an active fault line and a 1500 recurrence period, an earthquake in water is bound to happen any day now, and a tsunam i will hit the entire Lebanese coast from north to south. fortuitously complying with the Lebanese building code for construction and design is deem to satisfy conditions for earthquake and seismic analysis, but the law does not impose tsunami design to developers and consultants and the idea of a tsunami resisting structure or a vertical evacuation model was somehow absurd in the region. However now that we have solid create of a predicted tsunami, that idea doesnt look absurd anymore.Structural system A basic concept design of a Tsunami/Earthquake proof structure follows a number of consideration and guidelines. After observing past events, we can conclude that the major element that contributes to the survival of houses was the material used. While most small residences in Australia are timber and lightweight systems or even brick veneer and load bearing beleaguer system, the most robust model that can resist important horizontal or vertical loads is beef up concrete and or St eel structures. Multistory building are heavier and thus can prevent slip when horizontal action is applied and because above levels are not submerged they aid to resist lateral pass loads.Another key component is Orientation, when buildings are constructed in a direction parallel to the ocean, the wave will have a greater surface of contact, and therefore the lateral force will hit the plan faade with the lowest inertia. When they are built perpendicular to the ocean, the contact surface is smaller and the pressure will act upon a direction of highest inertia. An ideal design is to not resist entirely the wave and have the structure with 800mm thick reinforced concrete wall. It must be a combination between a robust design combined with weak members. In other word, the wave should pass through the building, without create the collapse of above stories. In order for the wave to flow though the ground level, non-load bearing walls have to breakaway to make passage for the wave. The se breakaway walls are masonry block walls, they collapse once struck by the wave. (FEMA TB9, 99)How vulnerable Structures are?Observation to partially damaged houses indicated that all elements can fail under tsunami load. rear end can be uplifted and soil can be scoured. Columns can be sheared causing one story collapse or leading to progressive collapses of all upper levels and impact force can completely dislocate columns. Beams can be bent lateraly due to horizontal action and were majorly cracked. Joints connecting two elements, such as vertical support with slab and foundation can fail entirely. Shear and bending mischance in walls have been detected, and punching shear where an axial element punches through a plan system was detect as well. However studying only the elements that failed is not enough engineers must also consider the components that survived. For instance, it was that facades that had openings such as windows and doors did not crumple as opposing to sides there were completely closed and thus have been ruined by the wave.Calculation exampleThis example consists of determining the actions caused by a tsunami on a structure of 2 basements, parking of area 1800 m2 each, make Level , Mezzanine and ten stories. The site is located 200 m from the shoreline, at elevation 5 m from the sea level near Beirut, Lebanon stature profile indicating the different slopes and location of the structure, taken from Google Earth 3DThe slope of the terrain is essential to steady down the wave parameters, specially height.The Federal Emergency Management Agency FEMA, has set guidelines to design structure from tsunami waves, FEMA P646 and FEMA P646A, 2005 shall be present in the below paragraphs to calculate all the loads generated on our structure. But first we need to determine the waves properties.A tsunami wave is defined by its inundation elevation R*, with is the height of the wave at its maximum penetration. Given the topography of our project, the wave will reach the steep slope and retrieve back, thats 510m from the shore. To determine the height, we will assume that the height is 10mTsunami LoadsAs per FEMA P646A, 2005 8 forces are acted upon the structureHydrostatic, Buoyant, Hydrodynamic, Impulsive , debris impact, Debris damming and Uplift forces, not to mention Additional gravity loads from retained water on empyreal floors.Hydrostatic force in the basement is when the water from tsunami is retained in the basement, and cannot escape because the basement wall outline prevent seepage, the water is trapped and the basements are compared to water reservoirs since the two basements are completely change with water. A static analysis on reservoir will therefore be conducted with water height 12m (=6m+8m)Fluid density s = 1.2 water = 1200 kg/m3pc is the hydrostatic pressure, pc = s.g.hpc (at GL ) = s. h = 1200 x 8 = 9.6 T/m2pc (at 1st Bas. ) = s. h = 1200 x (8+ 3) = 13.2 T/m2pc (at second Bas.) = s. h = 1200 x (8+6) = 16.8 T/m2Buoyant ForceThe uplift force as per Archimedes principle is as followThe reinforced concrete has a specific gravity of 2.5 T/m3, in our case the slab isnt a solid slab but made of hollow blocks with self weight equal to 0.63 T/m2Specific gravity of a 32 cm slab of hollow blocks is = 1.97 T/m3Water has a specific gravity of 1.2 T/m3When immersed in the water the slab wont weight the same actuality it would weigh less due to the fact it has a buoyant force acting upward making it lighter.And so in water, the specific gravity of the slab will become 1.97 T/m3-1.2 T/m3 = 0.77 T/m3If we take into consideration the thickness of the slab 32 cm it becomes 0.77 T/m3 x 0.32m = 0.246 T/m2The buoyant pressure decreased the specific gravity of the slab from 0.63 T/m2 to 0.246 T/m2 so it must be equal to 0.63 T/m2 0.246 T/m2 = 0.384 T/m2The buoyant force will be applied upwards as uniform surface load 0.384 T/m2 acting on floors of 1stBasement, Ground level, Mezzanine and first floor.