In planning to build the house, area of the house is one of the important aspects to be studied. Although the areas that have high risk of natural disaster to occur, there are still a lot of planning to build house over there. Therefore, in planning construction at each of the area like at hillside, the possibility of earthquake to occur, volcano eruption and others need to know about the composition and condition of ground soil, suitable design of the house for different area, the precaution need to take when build house at such of the area.
The mixture of sand and gravel is the most suitable type of soil with respects to drainage. Well graded gravels have a large bearing capacity, excellent drainage and a low frost heave potential. The movements of this mixture sand often result from condition in which there are too many voids between particles. A good mixture of particle size normally will increase stability.
Sand and clay do not compact well and erosion might easily occur. Clay soils have least susceptible to erosion but it often do not allow for proper drainage and have a higher potential for frost leaves. Moisture content of the soil also should be aware and the fluctuation of the content throughout the year will help prevent potential heating problems. For example, clay soils are more susceptible to thermal shrinking and expanding. Other problematic in soil is frost heaves. Ground freezing is responsible for soil expansion due to frost heave. The term "loess" deposits by some type of silt soil that are held together because of the particle bonding or cementing minerals. The containing of silts are very prone to severe frost heave. Because of the expansion by frost heave is great enough to lift even heavily loaded foundation and slabs. Fine grain soils retain moisture the best and are most susceptible to heaving. Capillary action responsible for frost heaves can be protected against it by a few ways. There are placing foundation below the freezing zone or insulating ground surface around shallow footings, use granular material to replace the frost sensitive soils, and interrupting capillary draw of moisture by putting a drainage layer of coarser material in existing soil.
Where steep slopes exist like at hillside area, there are possibilities of landslide to occur. This is caused by some of soil movement. The effect of gravity on unstable soil may cause lateral soil movement. This movement is typical of soil wanting to move sideways. Soils that affected by erosion or excess moisture content will result in unstable of the soil because it's poorly compacted.
The obvious effect on building system is earthquake. So, to build house in earthquake prone zones must concern of these aspects. To support downward vertical load, the typically foundation are designed. However, horizontal forces are produced by ground shaking during earthquake. In these areas, deposits of loose sand can also create problems as the intense shaking may cause the soil to liquefy.
The activities of excavation will disrupts soil, loosening it and creating more space between the particles of minerals and organic material of which soil is composed. After excavating for a home foundation, but before a foundation is installed, consolidated or compacted the soil using mechanical devices should be done to support the foundation. if the soil is not properly compacted, it will create a condition of the house structure above in which the weight will force soil to continue to compact slowly. This will result in settling of the soil beneath the foundation over the time. On the other hands, certain types of soil movement are preventable. Before building foundation is constructed, any fill soil should be properly places and compacted. In the soil, there should be no organic material because by over the time, these will decay and leaving voids that result in unstable conditions.
When we discuss about underground water, we know that it will cause severe problems. Groundwater exists nearly everywhere beneath the surface of the earth. It is water that fills the pore spaces between grains in rock or soil and fills fractures in the rock. Saturated zone below is separated by the water table. Water from unsaturated zone above is filling all pore space. Changes in rainfall will influenced the level of the water table. During wet seasons the water table tends to rise because more water infiltrates into the system and it tends to fall during dry seasons because less water infiltrates.
When a foundation is built on a site, it may interfere with the natural flow of groundwater. Let say if we want to built the house, it may even be over aquifers or seasonal flows. Moving water by erosive nature is well known, and there are possible of voids or excessive pressure build-ups. Because of the poor foundation soils, or because of lateral pressure caused by soil and groundwater on the wall exterior, basement walls can shift, crack and the possibility to collapse is higher. If the supporting soil settles, expands or lifts, concrete floor slabs can crack because of soil expansion or ground freezing.
One of the potential damage to earth shelters cause by water if it ponds around the shelter. Most important thing is avoiding sites with a high water table. Besides, other aspect that must be properly dealt with are drainage, both surface and sub surface and also waterproofing should be applied to the house.
Natural phenomena like flooding also may occur depend on the sites and the design. One of the higher risk for flooding is atrium design. Therefore the area surrounding land should slope away from the structure on all sides. The way to collect and remove additional water is by using a drain pipe at the perimeter of the roof edge. At the crest of the berm along the edge of the roof top, an interceptor drain is recommended for bermed homes. To divert water around the house, a drainage swale or gully can be build.
Slope stability affected by another aspect of water is fluid pressure. The pore water is still constrained to occupy the same space although a more compact structure formed by the rearrangement of grain by themselves as soil and rock get buried deeper in the earth. This can increase the fluid pressure to a point where the water then supporting the weight of the overlying rock mass. Friction is reduced by this and the strength holding the material on the slope is also reduced, resulting in slope failure.
The ways that homeowners can do to prevent landslide and slope stability problem when build house at the hillside area. Divert, contain and safely discharge water around and away from unstable slopes, yards and structures. Using sandbags to divert water from uncontrolled spilling, such as over curbs or from gutters and downspouts. Other than that, to protect sensitive and unstable area, use ground cover with plastic sheeting or tarps, burlap or other materials. Straw bales can stops velocity flow and erosion.
Safety tips that need to know are conduct water to a safe storm drain discharge point. Also keep gutters clean. Fix broken and leaking downspouts.to withstand a large variety of structural loading condition, concrete retaining walls can be constructed. They are useful in steep situation where protection is needed close to the top or base of a slope. The strength of retaining wall and materials made up of is highly dependent between them and how they are put together.
There are a few tips to build the design of earthquake resistant house. The building that can withstand collapse and also have the flexibility to reduce vibration from earthquake vibration is based on the two basically principle. They are structural rigidity and flexibility reduction.
What makes the structure more solid against shocks is rigidity principle structure of the house. During an earthquake occurs, the possibility of building collapse can be avoided by having rigidity of the structure. The columns and beams had to be strong binders and always followed by a good foundation. The principle of flexibility is about the possibility of building structure can be engaged in small scale to reduce vibration.
The principle use of lightweight materials is using material more lightweight so that it will not harmful when the collapse and the lighter because it may not really burden the existing structure. In the scale of earthquake, the structure displacement relationship that accepted is wood structure.
Traditional houses are using materials like bamboo and other plant material as their walls. Actually, these traditional houses are already suitable for earthquake situation because seismic vibration can be received very well by this material. When using bricks, practical columns as stiffeners need to be used to make sure that more lots were strengthened. On the roof of a brick wall, do not ever put the burden directly on it. In addition, to reduces vibration, flexibility of connecting with the columns is combining with the solid sheet of material conditions.
