A PROJECT ON G-4 RESIDENTIAL BUILDING

Situated at Kathmandu, Nepal

WORKED BY

RAJESH DULAL B.Tech Civil Engineering APG10910112027

UNDER THE GUIDENCE OF Niroj Kumar Thapaliya

ANALYSIS AND DESIGN OF RESIDENTIAL BUILDING

• PRINCIPLES OF PLANNING

• STRUCTURAL PLANNING AND DESIGNINGSLABSBEAMSCOLUMNSFOUNDATION

INTRODUCTION

PRINCIPLE OF PLANNING

• To arrange all the units of a building on all floors and at level according to their functional requirements making best use of the space available for a building.

• The shape of such a plan is governed by several factors such as climatic conditions, site location, accommodation requirements, local by-laws, surrounding environment, etc.

Factors to be considered in planning.

1) Aspect 2)Prospect3) Privacy 4)Grouping5) Roominess 6)Furniture Requirement7) Sanitation 8)Flexibility9) Circulation 10)Elegance11) Economy 12)Practical Considerations

Aspect: - ‘Aspect’ means individuality of the arrangement of doors and

windows in the external walls of a building which allows the occupants to enjoy the natural gifts such as sunshine, breeze, scenery, etc.

Aspect is a very important consideration in planning as it provides not only comfort and good environment to live in but from hygienic point of view also.

Prospect: - ‘Prospect’ in its proper sense, is the impression that house is likely to make on person who looks at it from out-side. Therefore, it includes the attainment of pleasing appearance by the use of natural beauties; disposition of doors and windows; and concealment of some undesirable views in a given outlook.

Privacy:- Privacy is one of the important principles in the planning of buildings of all types in general and residential buildings in particular. Privacy requires consideration in two ways: •Privacy of one room from another.•Privacy of all parts of a building from the neighboring buildings, public streets and by-ways.

Grouping:- Grouping means the disposition of various rooms in the

layout in a typical fashion so that all the rooms are placed in proper correlating of their functions and in proximity with each other. The objective of grouping of the apartments is to maintain the sequence of their functions with least interference. For example, in a residential building, dining room must be close to the kitchen; at the same time kitchen should be away from the drawing or the main living room, otherwise kitchen smells and smoke would detract them for their usefulness.

Roominess:- ‘Roominess’ refers to the effect produced by deriving the

maximum benefit from the minimum dimensions of a room. In other words, it is the accomplishment of economy of space at the same time avoiding cramping of the plan. It is essential particularly in case of residential buildings where large storage space is required, to make maximum use of every nook and corner of built-up area of the building before making an addition to the plinth area.

Furniture Requirements: - The functional requirement of a room or an apartment governs the furniture requirements. This is an important consideration in planning of buildings other than residential in particular and residential in general.In case of residential buildings, a room whether intended for bed room or kitchen or drawing room, the architect should take into account the furniture positions of all types likely to be accommodated, so that the doors, windows and circulation space do not prevent from placing of sufficient number of pieces.

Sanitation: - Sanitation consists of providing ample light, ventilation, facilities for cleaning and sanitary conveniences in the following manner:(i)Light: - Light has two-fold significance, firstly it illuminates and secondly from hygienic point of view. Light in interior buildings may be provided by natural or artificial lighting. Glare in light distracts and disables the vision and hence the source of glare may be avoided.

Generally, the minimum window area fir proper lighting should not be less than 1/10th of floor area.(ii)Ventilation: - It is the supply of outside air either positive ventilation or by infiltration into the building. Good ventilation is an important factor conducive to comfort in buildings. Poor ventilation or lack of fresh air in building, always produces headache, sleepiness, inability to fix attention, etc.

(iii)Cleanliness and sanitary conveniences:- Though the general cleaning and upkeep of the building is the responsibility of the occupants but even then some provisions to facilitate cleaning and prevention of dust are necessary in planning. The floors, as far as possible, should be of non-absorbent surface, smooth and proper slope should be given to facilitates washing with suitable outlets in the walls. Prevention of dust accumulation is essential. Dust helps the growth of bacteria and spread of the disease. Sanitary conveniences include the provision of bathrooms, water closets, lavatories, latrines, urinals, etc. in a building. Provision of such conveniences is not an optional matter but is a statutory requirement.

Circulation:- Circulation means internal “thoroughfares” or the movement space provided on the same floor either between the rooms or with in the room called horizontal circulation and between the different floors through stairs or lifts called vertical circulation. Passages, corridors, halls and lobbies serve the purpose of horizontal circulation, where as for vertical circulation normally stair or staircase, electric lifts, ramps, etc. are the means of access to different floors.Elegance:- Elegance is the effect produce by the elevation and general layout of the plan. The elevation, therefore, should speak out the internal facts and be indicative of the character.

Elevation should be impressive and should be developed together with the plan simultaneously. With the economy limitations, elevations should be aesthetically good and attractive.

Economy: - The economy may not be a principle of planning but it is certainly a factor, which effects planning. The economy may restrict the liberties of the architect and may also require certain alteration and omission in the original plan. The economy should not have any bad effect on grouping or aspect, however the prospect at the most to some extend can be sacrificed if need be. Economy should not have any evil effect on the utilities and safety of the structure.

STRUCTURAL PLANNING

Structural planning is first stage in any structural design. It involves the determination of appropriate form of structure, material to be used, the structural system, the layout of its components and the method of analysis.

As the success of any engineering project measured in terms of safety and economy, the emphasis today is being more on economy. Structural planning is the first step towards successful structural design.

Structural Planning of Reinforced Concrete Framed Building:Structural planning of R.C.C. framed building involves determination of:• COLUMN POSITIONSPositioning of columnsOrientation of columns• BEAM LOCATIONS• SPANNING OF SLABS• LAYOUT AND PLANNING OF STAIRS• TYPE OF FOOTING

STRUCTURAL DESIGNING

Structural design for framed R.C.C structure can be done by three methods:• Working Stress Method.• Ultimate Strength Method.• Limit State Method.WORKING STRESS METHOD OF DESIGN

It is earliest modified method of R.C.C structures. In this method structural element is so designed that the stress resulting from the action of services load as computed in linear elastic theory using modular ratio concept do not exceed a pre-designed allowable stress which is kept as some fraction of ultimate stress, to avail a margin of safety. Since this method does not utilize full strength of the material it results in heavy section, the economy aspect cannot be fully utilized in the method.

ULTIMATE STRENGTH METHOD OF DESIGNThis method is primarily based on strength concept. In this method the structural element is proportioned to withstand

the ultimate load, which is obtained by enhancing the service load of some factor referred to as load factor for giving

desired margin of safety. Since this method is based on actual stress strain behavior of the material, of the member as of the structure that too right up to failure, the values calculated by

this method agree well the experiment results.LIMIT STATE METHOD DESIGN

During the past several years, extension research works have been carried out on the different aspects of the research in the

actual behavior of member and structure has led to the development of design and approach of LIMIT STATE

METHOD OF DESIGN.

LIMIT STATE CONCEPTIn limit state method the working load is multiplied by partial factor of safety in accordance with clause 36.4.1 of IS – 456-

2000; And also the ultimate strength of material is divided by the partial safety in accordance with clause 36.4.1 of IS –456-2000;

and also the ultimate strength of the material is divided by partial safety in accordance with clause 36.4.2 of IS-456-2000.

Partial safety factor is introduced to reduce the probability of failure to about zero. When a structure or apart of a structure becomes unfit for use, it is said to have reached a limit state,

unfitness for use can arise in various ways and aim of limit state method of design is to provide an acceptable probability that the structure will not reach any of the limit states during its service

life span. Limit state can be broadly classified into two main categories.

LIMIT STATE OF COLLAPSE: It is the limit state on attainment of which the structure is likely to collapse. It relates to stability and strength of the structure. Design to this limit ensures

safety of the structure from collapse.

LIMIT STATE OF SERVICEABILITY: It relates to performance or behavior of structure at working loads and is based on causes

affecting serviceability of the structure. This limit state is concerned with cracking and deflection of the structure.

DESIGN PRINCIPLE, ASSUMPTION AND NOTATION ASSUMED

The notation adopted throughout the work is same as in IS-456-2000.

ASSUMPTION IN DESIGN1. Using partial safety factors for loads in accordance with clause

36.4 of IS-456-2000 as γf = 1.5γ2. Partial safety factor for material in accordance with clause 36.4.2 is IS-456-2000 is taken as 1.5 for concrete and 1.15 for steel.

3. Using partial safety factors in accordance with clause 36.4 of IS-

456-2000 combination of load. D.L. + L.L. 1.5

D.L. + L.L. + W.L 1.2

DESIGN CONSTANTSUsing M20 and Fe 415 grade of concrete and steel for beams, slabs,

footings, columns.Therefore: -

Fck = characteristic strength for M20-20N/mm2Fy = Characteristic strength of steel – 415N/mm2

ASSUMPTION REGARDING DESIGNSlab is assumed to be continuous over interior support and partially

fixed on edges, due to monolithic construction and due to construction of walls over it.

Beams are assumed to be continuous over interior support and they frame into the column at ends

S L A B SSlab are plain structural members forming floors and roofs of building

whose thickness is quite small compared to their other dimensions. These carry load primarily by flexure and are in various shapes such as square, rectangular, circular and triangular in buildings, tanks etc. inclined slabs

may be used as ramps for multistoried as parking. A staircase is considered to be an inclined slab.

The thickness of the reinforced concrete slabs ranges from 75mm to 300mm slabs are designed just like beams keeping the breadth of slab as unity depending on the system of units. Thus the total slab is assumed to the consisting of strips of unit width compression reinforcement is used only in exceptional basis in a slab.

BEAMS

A reinforcement concrete beam should be able to resist tensile, compressive and shear stresses induced in it . Concrete is fairly strong in compression but very weak in tension. Plain concrete beams are thus limited in carrying capacity by the low tensile strength. Steel is very strong in tension. Thus, the tensile weakness of concrete is overcome by the provision of reinforced steel in the tension zone to make a reinforced concrete beam.

SINGLY REINFORCED BEAMS In case of singly reinforced beam, the main reinforcement is provided near the tension faces of the beam.

DOUBLY REINFORCED BEAMSA doubly reinforced beam is that in which reinforcement is provided both for tension as well as compression face. A doubly reinforced section is generally provided under the following conditions.1. When the depth and breadth of the beam are restricted and it has to resist greater bending moment than a singly reinforced beam of that section would do.2. When the beam is continuous over several supports, the section of the beam at the support is usually designed as doubly reinforced section.3. When the member is subjected to eccentric loading.4. When the bending moment in the member reverses according to the loading conditions e.g., the wall of the under ground R.C.C storage reservoir, brackets etc.,5. When the member is subjected to shocks, impact or accidental lateral thrust.

DESIGN SPECIFICATION ACCORDING TO IS: 456-2000 AND SP: 16 EFFECTIVE DEPTHEffective depth of beams is the distance between the centroid of the area of tension reinforcement and the maximum compression fiber, excluding the thickness of the finishing material not placed monolithically.

CONTROL OF DEFLECTIONThe deflection shall generally be limited to the following:

The final deflection due to all loads including the effects of temperature, creep and shrinkage are measured from the as-cast level of the support of the floor, roofs and all other horizontal members not normally exceed span/250.

The deflection including the effects of temperature, creep and shrinkage occurring after erection of partitions and the application of finishes should not normally exceed span/350 or 20mm whichever is less.

SHEARA beam subjected to shear force and bending moment experience diagonal tension. Vertical shear force alone is not as critical when compared with the result due to the intersection of bending moment and shear force.The resultants of these stresses produce diagonal tension, which may develop crack in the beam.To take care of this resultant diagonal tension shear reinforcement is provided in two forms.

1. Cranked bars2. Stirrups

-Vertical-Inclined.

COLUMNSA column or strut is a compression member, which is used

primarily to support axial compressive loads and with a height of at least three times it’s least lateral dimension. A reinforced concrete column is said to be subjected to axially loaded when the line of the resultant thrust of loads supported by the column is coincides with the line of C.G. of the column in the longitudinal direction. Depending upon the architectural requirements and the loads to be supported, R.C.C. column may be cast in various shapes i.e. square, rectangular, hexagonal, octagonal or circular.

COLUMN POSITIONS

Following are some of the guidelines principles for positioning of columns.Column should be preferably located at or near the corner of the building and at intersection of the walls, because the function of the column is to support beams which are normally placed under walls to support them. The columns, which are near to property line, can be exception from above consideration as the difficulties are encountered in providing footing for such columns.When center to center distance between the intersection of the walls is large or where there are no cross walls, the spacing between two column is governed by limitations on spans of supported beams because spacing of column beside the span of the beams. As the span of the beam increase as the required depth increase and hence its self weight.

ORIENTATION OF COLUMNS:

Column normally provided in the building are rectangular width of the column not less than the width of support for effective load transfer. As far as possible, the width of the column shall not exceed the thickness of the walls to avoid the offsets. Restrictions on the width of the column necessitate the other side (the depth) of the column to be larger the desired load carrying capacity. This leads to the problems of orientation of columns.

Effective LengthThe effective length of a column is defined as the length between the points of contra flexure of the buckled column. The code has given certain values of the effective length for normal usage assuming idealized and condition shown in appendix D of IS 456 (table 24)A column may be classified as follows based on the type of loading.Axially loaded column.A column subjected to axial load and uni-axial bending.A column subjected axial loads and bi-axial bending.Axially Loaded ColumnsAll compression members are to be designed for a minimum eccentricity of load into principal directions. In practice, a truly axially loaded column is rare, if not non-existent. Therefore, every column should be designed for an eccentricity.

Axial Load and Uniaxial BendingA member subjected to axial force and uniaxial bending shall be designed on the basis of The maximum compressive strain in concrete in axial compression is taken as .002The maximum compressive strain in concrete at the highly compressed extreme fiber in concrete subjected to axial compression and when there is no tension on the section shall be 0.0035 minus 0.75 times the strain at the least compressed extreme fiber.Design charts for combined axial compression and bending are given in the form of interaction diagrams in which curves for Pu /fck bD Vs Mu /fck b D2 are plotted for different values of p/ fck where P is the reinforcement percentage.

Axial Load and Biaxial BendingThe resistance of a member subjected to axial fore and biaxial bending shall be obtained on the basis of assumptions given in

38.1 and 38.2 with neutral axis so chosen as to satisfy the equilibrium of load and moments about two axes.

Alternatively such members may be designed by the following equation:

Mux,Muy = Moment about x and y-axis due to design loadMux1, Muyl = Maximum uniaxial moment capacity for an axial

load of pu, bending about x and y axis respectively and it is related to pu/puz

Puz = 0.45 x fck x Ac + 0.75 x fy x AscFor values of Pu/puz = 0.2 to 0.8, the values of an varies from 1

to 2For values less than 0.2 =1.0

For values greater than 0.8, = 2.0

Thank You