ASSIGNMENT HELP ON PLANNING AND DESIGNING OF A RESIDENTIAL BUILDING

INTRODUCTION

In this project work is proposed to design a Residential building (G+1). The height of each floor is 3.0m from floor level to top of the roof. It is provided with R.C.C, roof slab supported on R.C.C frames and masonry infill. The columns are connected with beams at roof level. The main outer walls and cross walls are 230mm thick brick masonry in cement mortar.

The slab, beams, columns, staircase and footings are designed as per IS 456- 2000. The designs are based on the limit state design method. Imposed and dead loads are only considered for design excluding the earthquake and wind loads. The drawings are prepared using AutoCAD.

DESIGN

Design plays an important role in the performance of any structure. The aim of design is the achievement of an acceptable probability that structures being designed will perform satisfactorily during their intended life.

With an appropriate degree of safety, they should sustain all the loads and deformations of normal construction and use and have adequate durability and adequate resistance to the effects of misuse and fire. Designs of all the structural elements are done as follows.

WALL

Under the Experimental Projects Scheme of the National Buildings Organization, 50 residential units in 5 storeyed blocks, having one brick, that is 25.4 cm thick loadbearing brick masonry walls in all the storeys were constructed at Manicktola, Calcutta in 1975 and construction of 20 residential units in‟ 5 storeyed blocks, having one brick, that is, 22.9 cm thick walls, have been constructed in New Delhi.

Buildings are presently designed in western countries mostly by allowable stress method of design. Walls are designed as vertical cantilevers with no moment transfer at wall to floor connection. Lateral loads are distributed to cross walls according to their stiffness and locations by the diaphragm action of floor and roof
slabs acting as horizontal beams. It has been found that eccentricity of load from a slab at the top of a masonry element gets reduced at the bottom support of the wall. In some countries limit state design method is now coming into vogue because of better reliability and economy obtained through the adoption of this method. For large and important projects strength of masonry is based on „for-the-job‟ prism tests instead of lacing reliance on standard tables. In seismic zones masonry consisting of hollow blocks is reinforced vertically to take tension. In some countries structural advantage is taken of the fact that use of through-wall unit results in stronger masonry. In tall single storey long-span buildings such as churches, sports stadia, large halls, etc, use of Diaphragm type masonry wails is proving to be an economical innovation.

Now Building Regulations incorporate the concept of engineered masonry contained in the Code, whereas earlier in our country one brick wall could only be a single storey building. Presently one brick walls are built-up to 4-5 storeys in many parts of the country.

SLAB

The thickness of the slab to be provided is 150mm. The slab is designed as two way and one way slab by limit state method using M25 concrete and Fe415 steel adopting the guidelines of IS 456 and SP-16.

BEAM

The beams are designed to support a given system of loads such as walls, slabs and floor. The cross sectional dimensions are assumed based on serviceability requirements. The reinforcements in beams are designed for flexure and shear force along the length of the beam based on the results of structural analysis for limit state of collapse. The designed beam is checked for the limit state of serviceability and safety.

FOOTING

Isolated rectangular footing is provided. The depth of footing provided is 700mm. The footing is checked for flexure, transverse shear and punching shears.

LOAD CALCULATION

Live load and dead load are considered. The dead load is calculated from the weight of the elements like the walls, slabs, beams .