 ANALYSIS AND DESIGN 1.docx (Size: 78.57 KB / Downloads: 159) INTRODUCTION The Residential Building is generally considered as one that is taller than the maximum height which people are willing to walk up. It thus requires mechanical vertical transportation. This includes a rather limited range of building uses, primarily residential apartments, hotels, and office buildings, through occasionally including retail and educational facilities. Now-a-days where there is lack of financial resources, it is acceptable ion why majority of individuals prefer to have a standard way of living. But if you have the capacity to go to better lifestyle then why not grab it. There are a lot of advantages that can be achieved with high rise living, and these are not seen easily. A thorough observation will let you know benefits of it and understand that living high-rise is definitely advantageous. Residential buildings are normally located at every place. But choosing a good location on where to stay is very much essential. Once your place is accessible to almost everything, like your office, your school, shopping malls, restaurants, public transportation and other key areas, you can save a lot of time and fuel. SPANNING OF SLABS • This is decided by supporting arrangements when the supports are only on the opposite edges (or) only in one direction, then slab acts as aONEWAYSLAB. • In general, when the rectangular slab is supported along its 4-edges it acts as a ONE WAY SLAB { i.e., Ly/Lx>2} and TWO WAY SLAB when {Ly/Lx<2} Where Ly represents the long span & Lx represents the short span. • However the two way action of slab not only depends on the aspects ratio Ly/Lx but also the ratio of the reinforcement in the two direction. • Therefore designer is free to decide as to whether the slab should be designed as one way slab (or) two way slab. This decision may be taken considering the following points. BEARING CAPACITY OF SOIL The size of the foundation on permissible bearing capacity of soil. Total load per unit are under the foundation must be less than the permissible bearing capacity of the soil tp prevent the excessive settlement. It is important to have an engineering survey made of the soil under a proposed structure so that variation in the strata and the soil properties can be determined. Drill holes or trial pits should be sunk in situation test such a penetration test performed and the samples of the soil taken earth bearing pressure and if necessary calculating possible settlement of a structure. In the design of foundations, the areas of the bases in contact with the ground should be such that the safe bearing pressures will not be exceeded. Settlement takes place during the working life of the structure. These loads are to be properly transmitted, footings must be designed to prevent excessive settlement or rotation, to minimize differential settlement and to provide adequate safety against sliding and overturning. CHOICE OF FOOTING TYPE The type of footing depends upon the load carried by the column and the bearing capacity of type supporting soil. For framed structures under study, isolated column footing are normally preferred in case of soil with very low bearing capacities. If such soil or black cotton soil exists for greater depth pile foundation can be an appropriate choice. If columns are very closely spaced and bearing capacity of soil is low, raft foundation can also be an alternative solution. For a column on a boundary line, a combined footing or a strap footing may be provided. WORKING STRESS METHOD Working stress method of design is also known as modular ratio method (or) the elastic ratio method. It is the earliest modified method of design if R.C.C structures and it is based in criteria that the actual stress development in the material under the action of working load must be limited to set of allowable values, the theory is based on elastic theory using modular ratio concept. The sections are designed in such a way that the stresses are within the permissible limits. However, this method does not utilize full strength of material, resulting in a heavy section. The economy too cannot be fully utilized in this method ULTIMATE STRESS METHOD This method is also known as the factor method. In this method the actual strength of a section is related to the actual load. Service loads are multiplied with load factors to get the ultimate designed loads and evaluated thus proportioning the section to carry stress up the torsion values are evaluated thus proportioning the section to carry up the ultimate strength of material. Here the moments and shear are still established by elastic analysis mostly rather than by hinge formation and also requires strict quality control. LIMIT STATE METHOD This method is based on the limit state concept, i.e. the structure is designed to with stand safely all loads liable to all loads acts on its through its life and shall also satisfy the serviceability requirements such as excessive deflection, cracking and vibrations. Limit state is the acceptable limit for the safety and serviceability requirements before failure of safety and characteristic loads, thus the members are proportional to carry the limit designed loads and the materials are stressed to limit designed strength. |
Reference: http://seminarprojects.com/Thread-analysis-and-design-of-residential-building-and-cost-evaluation#ixzz2J2F81wgi
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