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SILPARUPA PTC KARIMNAGARArchitects & Engineers Classroom Block

DESIGN BASIS REPORT

FOR

PROPOSED CLASSROOM BLOCK FOR POLICE TRAINING COLLEGE

AT KARIMNAGAR

SILPARUPAARCHITECTS & ENGINEERS

8-2-293/K/49, I - FLOOR, PHASE-I I I ,KAMALAPURI COLONY,SRINAGAR COLONY EXTENSION,

HYDERABAD-500073.TEL: 040 - 23542340. Mob: 98491-11719.

E- Mail: [email protected]

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INDEX

1 FOREWORD

2 DESIGN PHILOSOPHY

3 MATERIALS

3.1 Concrete3.2 Reinforcement

4 LOADING PARAMETERS

4.1 Imposed Dead Loads4.2 Imposed Live Loads4.3 Seismic Loads

5 LOAD COMBINATIONS

6 NOMINAL COVER TO REINFORCEMENT

7 PROPOSED APPROACH OF STRUCTURAL ANALYSIS

8 STRUCTURAL DESIGN METHODOLOGY

9 FOUNDATION SYSTEM

9.1 Foundations for Building9.2 Precaution against presence of chemicals

10 DESIGN STANDARDS

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1.0 FOREWORD

The intent of this document is to identify and record all the pertinent input requirements,

analysis & design criteria for structural design of the building. It is aimed at formulatingthe basis of the structural analysis, design & detailing work that the Structural Engineer

had planned in delivering the structural scheme of the buildings which will be compatiblewith the architectural theme, satisfy the functional needs, at the same time confirmingto the Indian Standards and other applicable building norms to achieve safe, stable,strong and yet optimally economical structures.

The parameters adopted in this report are going to be the basis of the structural designand calculations. This report covers the minimum design requirement to establish theunified design basis that will form the overall design philosophy to be adopted in the

structural design of the proposed building.

The design will aim to achieve

Structural & functional integrity.

Desirable Structural performance under characteristic service design loadings.

Resistance to loads due to natural phenomena i.e. wind and earthquakes.

Structural durability & maintainability.

2.0 DESIGN PHILOSOPHY

Customer : AP STATE POLICE HOUSING CORPORATION

Location : KARIMNAGAR, ANDHRA PRADESH

The proposed project consists of Classrooms building for PTC. The proposed structuralsystem for the Building comprises of conventional RCC Structure with Reinforced

concrete columns, beam, slabs etc for construction.3-D Analysis of the building structureis carried out using STAAD Pro software package and analysis results shall be used for

designing the various elements. As the Length of the Structure is greater than 40mts,Expansion joints are introduced. So, four Staad files are generated namely A&C, B, D&E,F along with their Seismic files. Footings, Slabs, and staircase are designed manually inexcel sheets. Respective supporting files for the design of the structure are also attachedas Annexure1. The Structure is designed as per Limit State Method.

3.0 MATERIALS

The self-weight of the various elements are computed based on the unit weight of

materials as given below: -

Materials Unit weight (kN/m3)

Steel 78.50

Plain Cement Concrete 24.00

Reinforced Cement Concrete 25.00

Cement Concrete Solid Block work 20.00

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Brick 20.00

Soil (Moist condition) 20.00

Water 10.00

Aluminium 28.00

Glass 25.00

Density of finishes 20.00

Cement Concrete screed 24.00

Normal weight aggregates shall be considered for arriving at self-weight of

all Concrete works.

3.1 CONCRETE

Concrete item Grade Max. Size of

Aggregate(mm)

Type of cement

Grade 43

Foundation M20 20 OPC

Columns M20 20 OPC

Beams M20 20 OPC

Slabs M20 20 OPC

Staircase M20 20 OPC

Normal weight aggregates are considered for all concrete works.

3.2 REINFORCEMENT

Steel reinforcement shall be of Grade Fe415 conforming toIS: 1786-1985.

4.0 LOADING PARAMETERS

4.1 Imposed Dead Loads

Apart from the superimposed live loads, other dead loads due to stationerybuilding elements are also mentioned hereunder, which arise due to walls, floor

finishes, services, etc.

The imposed loads that are envisaged to act permanently (wherever applicable)are as follows: -

Items Intensity in kN/m2 of

plan area

Weatherproof course & Thermalinsulation on Roof

Depends on thethickness, slope and kindof material to be used forweatherproofing.(1.5)

Floor Finish on Ground, First &Second floor. 1.5

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a) Dead load of slab:-

Slab 150mm thk = 0.15*25=3.75 kn/m2Floor finish = 1.8 kn/m2

Total = 5.55 kn/m2

b) Sunken slab load :-Sunken slab(300mm brick bat fill)= 0.3*18=5.4kn/m2

Partition load = 0.0 kn/m2Total load = 5.4 kn/m2

c) Stair case load :-

Total load on staircase =12.42 kn/m212.42*5.62*5.6=390.88knApplied as member load on both opposite beams = 390.88/2/5.6=34.90 kn/m

d) Wall load:-

External Brick wall load =(3.66-0.6)*0.25*20=15.30kn/mInternal Brick wall load = 15.30/2=7.65 kn/mParapet wall load = 0.9*0.25*20=4.50kn/m

4.2 Imposed Live Loads

The superimposed load or otherwise live load assessed based on the occupancyclassifications as per IS: 875 (Part 2) 1987 is listed as below:

Location Occupancy classification UDLKn/m2

General floor area All rooms 2.0

Lobby area Corridors, passages and staircasesincluding fire escapes

2.0

Floor area Toilets 2.0

Terrace area Floor area 1.5

Sunken filling Toilets 5.4

4.3 Seismic Loads

The loading due to earthquake is assessed based on the provisions of IS:

18932002. As per this code, Karimnagar lies in Zone III.

Zone factor Z = 0.16

Importance factor I will be considered as 1.0

Response reduction factor R for ordinary moment resisting frame is 3.0

Staad1:-

Length of the building up to expansion joint=27.39m

Width = 17.45 m

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Height = 12.48 m

Time period = 0.09h/sqrt(dx)

T = 0.09*12.48/SQRT(27.39)=0.214

Time period = 0.09h/sqrt(dz)

T = 0.09*12.48/sqrt(17.45)=0.269Staad2:-

Length of the building up to expansion joint=37.78m

Width = 28.21 m

Height = 12.48 m

Time period = 0.09h/sqrt(dx)

T = 0.09*12.48/SQRT(37.78)=0.183

Time period = 0.09h/sqrt(dz)

T = 0.09*12.48/sqrt(28.21)=0.212

4.4 Wind Loads

As per IS: 875- (Part III)

Basic Wind Speed for Karimnagar Vb= 44 m/sec

K1 = Probability factor =1.0 (For all general buildings)

K2 = Terrain, Height and structure size=0.98

K3 = Topography factor=1.0

Pz =0.6 * Vz2 N/m2Design wind Pressure Pz = 1.115 kN/m2 (for maximum height)

5.0 LOAD COMBINATIONS

The various loads shall be combined in accordance with the stipulations in IS:875 (Part 5) 1987. Whichever combination produces the most unfavourable effect in thebuilding, foundation or structural member concerned shall be adopted.

Following load combinations of the member forces will be considered for arriving at the

design forces.

Values of Partial Safety Factor f for Loads

Load

Combination

Limit State of Collapse Limit State of

Serviceability

DL LL WL/EL DL LL WL/EL

DL + LL 1.5 1.5 -- 1.0 1.0 --

DL + WL 1.5 or 0.9$ -- 1.5 1.0 -- 1.0

DL+ LL + WL 1.2 1.2 1.2 1.0 0.8 0.8

DL + EL 1.5 or 0.9$ -- 1.5 1.0 -- 1.0

DL + LL + EL 1.2 1.2 1.2 1.0 0.8 0.8

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$ This value is to be considered when stability against overturning or stress reversal is critical

Wind load and earthquake load has been considered for both X & Z directions.

DL - Dead loadLL - Live loadWL - Wind loadEL - Earthquake load

Whenever imposed load is combined with earthquake load the appropriate part of

imposed load as specified in IS: 1893 2002 will be used both for evaluating earthquakeeffect and for combined load effects used in such combination.

6.0 NOMINAL COVER FOR REINFORCEMENT

From Durability requirement, exposure condition is assumed as mild for Structuralelements above ground floor level and moderate for Structural elements below ground

floor level.

The Nominal cover to reinforcement to meet Durability requirement shall be as follows: -

Mild - 20 mmModerate - 30 mmFootings - 50 mm (minimum)

For Two hour fire resistance requirement, The Nominal cover to reinforcement shall beas follows: -

Footings - 50 mm (minimum)

Columns - 40 mm or diameter of largest bar,Which ever is greater?

Slabs - 20mmBeams - 25 mm

For any other elements not specified above, clear cover shall be as per the clause 26.4of IS: 456-2000.

7.0 PROPOSED APPROACH OF STRUCTURAL ANALYSIS

The project mainly comprises of design of Classrooms building. The buildings is modelledand analysed as R.C.C Framed structure with columns/ beams and slab etc. The buildingstructure is analysed using STAAD-Pro V8i software package. Both vertical and lateralloads that are likely to act are considered for the analysis. Appropriate loads and itscombinations are considered as per relevant clauses in IS codes, the most unfavourableeffects are chosen for the design.

Space frame analysis of the structure for seismic loads.

Geometrical dimensions, member properties and member-node connectivity, includingeccentricities are modelled in the analysis problem. Variation in material grades, are also

considered.

Seismic and wind load derivations will be carried out using coefficients / factors inaccordance with the relevant codes.

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The permissible values of the load factors and stresses will be utilised within the purviewof the Indian Standards.

The computer analysis will produce individual member forces, reactions at foundationlevel and deflection pattern of the entire structure as well as individual members. This

data will then be used to confirm / review the member sizes and arrive at the mostappropriate design of the structural members. Some re-runs of the analysis programme

might be required for arriving at the optimum structural space frame characteristics thatsatisfy the strength and stability criteria in all respects.

8.0 STRUCTURAL DESIGN METHODOLOGY

All R.C.C structures will be designed according to the Limit State Method as specified inIS: 456 2000.

Materials of construction will be predominantly concrete with consideration for strength

and durability. Minimum grade of concrete is suggested as M 20, in view of the level ofstresses to be borne both in compression as well as flexural members.

High Yield Strength Deformed bars conforming to IS: 1786 with Fy = 415 Mpa will beused as reinforcement.

Covers to reinforcement shall be in accordance with IS 456 corresponding to moderateexposure conditions and to satisfy fire rating of 2 hrs.

9.0 FOUNDATION SYSTEM

9.1 Foundations for Building

Appropriate foundations are required to transfer the load from the columns to thesub strata. Isolated footings and Combined footings are designed to transfer theload from column to the soil. The dimensions of the footings are sized based onthe column reaction and safe bearing capacity, and thereby sufficientreinforcement is provided. The foundations have been designed for the SafeBearing Capacity of 150 Kn/sq.m.

10.0 DESIGN STANDARDS

In the analysis, design and detailing of the building, the following relevant Indian

Standard Codes shall be used.

Sl.No. Code Description

1. IS-875 (Part 1) 1987 Code of Practice for Design Loads (other thanearthquake) for buildings and structures Unit weightsof buildings materials and stored material.

2. IS-875 (Part 2) 1987 Code of Practice for Design Loads (other thanearthquake) for buildings and structures Imposedloads.

3. IS-875 (Part 3) 1987 Code of Practice for Design Loads (other than

earthquake) for buildings and structures Wind loads.

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Sl.No. Code Description

4. IS-875 (Part 4) 1987 Code of Practice for Design Loads (other thanearthquake) for buildings and structures Snow loads.

5. IS-875 (Part 5) 1987 Code of Practice for Design Loads (other thanearthquake) for buildings and structures Special

loads and load combinations.

6. IS: 456 2000 Code of Practice for Plain and Reinforced Concrete.

7. IS: 1786 1985 Specification for High Strength Deformed Steel Bars

and Wires for Concrete Reinforcement.

8. IS: 432 (Part 2) - 1982 Specification for Mild Steel and Medium Tensile SteelBars and Hard Drawn Steel Wire for ConcreteReinforcement Hard Drawn Steel Wire.

9. IS: 13920 1993 Ductile detailing of reinforced concrete structuressubjected to seismic forces - Code of practice

10. IS: 1904 1986 Indian Standard Code of practice for design & construction foundations in Soil : GeneralRequirements

11. IS: 2062 1999 Steel for General Structural Purposes. Specification.

12. IS: 1161 1998 Specification for Steel tubes for Structural Purposes.

13. IS: 800 1984 Code of Practice for General Construction in Steel.

14. IS: 1893 2002 Criteria for Earthquake resistant design of structures.

15. IS 2950 Indian Standard Code of practice for design & construction of raft foundation (Part 1)

16. IS 2974 Code of practice for design & construction of machine

foundation.

17 IS 4326 Code of practice for earthquake resistant design andconstruction of buildings

18 SP-16 Structural use of concrete. Design charts for singlyreinforced beams, doubly reinforced beams andcolumns.

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