Diwas Kumar Jhimi_revised

A

STRUCTURAL DESIGN

REPORT

OF

THE PROPOSED BUILDING OF RESIDENTIAL

OWNER:

SUBMITTED TO:

1

TO WHOM IT MAY CONCERN

This report comprises the summary of the residential building of Mr. Diwas Kumar Jhimi 16-Dharan Nepal. The reports consist of the design procedures adopted, the assumptions made, the inputs made in the design and the design output. During the design, it is assumed that the client will completely follow the architectural as well as the structural design. It is also assumed that the construction will be supervised by professional engineer.

The designer will not be responsible if any alterations to the structural system is made by the client or the contractor without the prior written permission from the designer, or the alterations to non-structural system is made such that the weight of each individual floor or the weight of the whole building is altered by more than 10% of design weight of each floor and the total weight.

The design calculations and derivations are limited to only a minimum to let the concerned people know the methodology adopted. However, the calculations may be provided to the client or concerned authorities when needed, upon request. Hence the building is safe.

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TABLE OF CONTENTS

S.N. Title

Page

No.

1

Introduction

3

2

Salient features

3

3

Design Approach and Methodology

6

4

Preliminary Design

8

5

Final Analysis

9

6

Design Methodology

11

7

Analysis Output

13

3

1.0 Background

This report summarizes structural analysis and design of the Residential building for Dharan Sub-Metro politician City. The analysis and design has been based on the prevailing codes that are in practice in Nepal, the National Building Code of Nepal and the IS codes at places.

2.0 Salient Features

2.1 Project Information:

Owner : Mr. Diwas Kumar Jhimi

Building Type : Residential Building

Location : Dharan-16

Plot no. :

Land Area :

Plinth Area :

2.2 Building Features:

Type of Structure: RCC Framed Structure

Storey: 2-Storey

Storey Height: 3.048m

Total Height: 6.096 m

2.3 Site Condition:

Soil Type: III (for seismic consideration as per NBC 105) Seismic Zone Factor: 1.0

4

2.4 Material Specification:

Considering Architectural, Economic and strength demands reinforced cement concrete (RCC) is used as the major structural material. The selected material also confirms the availability and ease in construction. The concrete grade used is M20 as per Indian Standard Specification. This material provides minimum grade of structural concrete and favorable for easy production and quality control as well.

Fe 500 is provided as longitudinal and shear reinforcing in Beams, Columns, foundations, and slabs wherever RCC is used.

Considerations of material for loading and strength parameter are as detailed below:

Structural Components: Concrete:

Grade: M20

Characteristic Compressive Strength: 20 N/mm2

Unit Weight: 25.0 KN/m3

Young’s Modulus of Elasticity (E): = 5000 √ fck N/mm2

≈ 22360680 KN/m2 (for M20) Steel Reinforcement:

Grade: Fe 500 (for both longitudinal and shear reinforcement)

Non-Structural Components: Brick wall:

Unit Weight: 18.85 KN/m3

Strength: Not Available

Finishing: Plaster:

Unit Weight: 20.4 KN/m3

Flooring: Screed + Punning

5

2.5 Loading Details

Number of Storey 2 Storey Loading in General

(Gravity loads)

Structural Self Weight

Live Load for residential services

Dead load of finishing materials for floor

Panel walls 250mm & 125mm thick brick walls without openings 125mm thick brick walls with 30% openings

Partition walls 125mm thick (half brick) walls with 30 & 20% openings Parapet walls 125 mm thick (half brick) wall height 0.8m

Live Load As per IS 875 Part II

Lateral Loading As per NBC 105:1994

The loads distributed over the area are imposed on area element and that distributed over length are imposed on line element whenever possible.

Where such facility is not feasible, equivalent conversion to different loading distribution is carried to load the Model near the real case as far as possible.

For lateral load, necessary calculations were performed and checked using NBC 105: 1994 for response spectrum method.

Different load combinations based on Nepal National Codes are developed and used for design purposes.

Load Combinations:

The load combinations are based on NBC 105: 1994 Static Load Combination:

1.5 DL + 1.5 LL Seismic Load Combinations:

1.0 DL + 1.3 LL±±±± 1.25 EQ 0.9 DL ±±±± 1.25 EQ

For seismic loading, mass equivalent to the load that composed of 100% of Dead load and 25% of Live load is taken into consideration.

The Earthquake lateral loads were used in the combination from the Self-Generated Load on the Seismic coefficient Method.

6

3.0 Design Approach and Methodology:

3.1 Introduction

The structure is analyzed for full Finite Element. Beams and columns modeled as frame (line) elements with five and three internal stations. All floor slabs are modeled as Shell (Area) elements with sufficient and appropriate meshing. Modulus of elasticity and Poisson’s ratio for used material i.e. M20 grade concrete (as per Indian Specification) are taken accordingly and section properties used are based on Preliminary section sizing with consideration for deflection, minimum size specified and serviceability. Computation for stiffness as a whole is carried out using FEM based latest software. Full Modal Analysis is carried out up to twelve modes confirming more than 95 % seismic mass participation and it is applied for lateral seismic force distribution that generated with NBC 105 based Spectral Function for Soil Type-III.

For Section Design and Check, suitable Load combinations as suggested in NBC105:1994 and if not covered in that, IS 1893- 2002 is referred with consideration of Envelopes of internal Forces developed.

Foundation design is carried out to satisfy strength and stability requirements. 3.2 Software used: (Introduction to Analysis software)

The analysis for the structural system was carried out using ETABS 2016 ver 16.0.0 is a product of computers and structures Inc, Berkeley. It is a FEM based software having facility of RC Design based on IS-456:2000

3.3 Structural Performance:

Structural response under limit state of serviceability is thoroughly checked. The force and stiffness relationship resulting the deflection under various load cases and combined action of forces are duly evaluated. Basically short-term elastic deflection due to vertical loads and lateral deflection due to seismic forces are of major importance along with the long-term deflection of beam elements under sustained loading condition due to

shrinkage and creep are also taken into account.

7

Maximum vertical deflection in all components that resulted under vertical load of combined effect of self, imposed dead and live load are checked for every element and maintained to be within permissible limit. Short-term elastic deflection and long-term deflection due to shrinkage and creep due to sustained loads also are maintained within permissible limits for all the elements.

3.5 Deformation under Lateral Loads:

Effect of lateral load due to seismic force is analyzed using self-generated seismic load compatible with Codal provision. The distribution of lateral force at different parts of the structure is done based on the response under unit force. Using Complete Quadratic Combination (CQC) method of modal combination combines the deformations, and related forces reported.

3.6 Recommendations:

The following recommendations are made:

• Materials used shall confirm minimum standard specified before use. Primarily the cement, aggregate, sand and steel shall be used that confirms to NS or IS standard. • Batching, mixing, placing and curing of concrete and steel fabrication and placing

shall be done as per standard practice.

8

4.0 Preliminary Design

The Preliminary Design was done using the prevailing thumb rules and span consideration.

Slab: The slab is designed based on IS456:2000. The slab is designed to meet the deflection criteria for the slab.

Beam: The beam is designed based on IS456:2000. The slab is preliminarily designed to meet the deflection criteria as well as the moment requirements for the span.

Column: The column is preliminarily designed to meet the stiffness criteria for the building.

Staircase: The staircase is designed to satisfy the moment requirement as well as the deflection criteria.

The sizes of the structural components are as given below: Sizes of Structural Components:

Slab: 5” thick RCC (M20) Slab

Beam: Rectangular Beams size- 10” X 15” (BXD)

Column: Square, size- 12”X 12” (HXB)

Staircase: Waist Slab 5” thick

9

5.0 Final Analysis

5.1 Load Calculations:

Refer Table: Load Intensity of Building Components Live Load: 2.0 KN/m2 (for all rooms)

Live Load: 3 KN/m2 (for staircases and lobbies)

Roof Live Load: 1.5 KN/m2 (for roof accessible), 0.75 KN/m2 (for roof inaccessible)

5.2 Seismic Lump Load:

Seismic weight: Comprises Dead Load+ 25% of Live Load (as per IS Code for live load intensity ≤ 3 KN/m2)

Seismic wt. at ith floor level (WI) = (Total dead load of all components i.e. Beam, Slab, Columns And Walls for ½ height above and ½ height below the floor level + 25% of live load)

n

Total Weight of the frame, W= ∑ Wi Where, n = total number of storey I=1

Seismic Wt. of Building W = 1494.7605 KN Base Shear Calculation:

As Per NBC 105:

Total Horizontal Base Shear V= Cd × W Where, Cd= C×Z×I×K Where,

Basic Shear Factor (C) = According to time period of vibration and Soil type Seismic Zoning Factor (Z) = For Dharan

Importance Factor (I) = According to the type of building Performance Factor (K) = for the moment resisting frame

Distribution of design seismic force: Fi = Design Seismic Force at floor Level I Wi = seismic wt. at ith floor level

hi = height of floor i measured from base According to NBC 105:1994

10

Soil type = III

Time period (T) = 0.06 × H0.75 = 0.233 Sec

C = 0.08 (from Fig 8.1 of NBC105:1994) Z = 1.00 (for Dharan, Fig 8.2 of NBC105:1994)

I = 1.0 (for Residential Bldg., Table 8.1 of NBC105:1994) K = 1.00 (for Ductile Moment resisting Frame, Table 8.2 of

NBC105:1994) Cd = C×Z×I×K

= 0.08

Total Horizontal Base shear Vx = Vy = 0.08*1494.7605

Total Horizontal Base shear Vx = Vy = 119.5808 KN

5.3 Load Cases:

Dead : Self Weight of the building structural components (Beams, columns and slabs) Finish : Weight of the finishing of the slabs as well as staircases (including steps). Wall : Wall loads (inclusive of plaster)

Live : Live load in the building area elements.

Rlive : Live load in the terraces both accessible and inaccessible (not including in seismic behaviour)

EQX : Spectral Seismic Load in X – Direction EQY : Spectral Seismic Load in Y – Direction

5.4 Load Combination:

DL = 1.5Dead + 1.5Finish + 1.5 Wall + 1.5 Rlive + 1.5Live DQX = 0.9 Dead + 0.9 Wall + 0.9 Finish ± 1.25 EQX DQY = 0.9 Dead + 0.9 Wall + 0.9 Finish ± 1.25 EQY

DLEQX = 1.0 Dead + 1.0Wall + 1.0 Finish + 1.3 Live ± 1.25 EQX DLEQY= 1.0 Dead + 1.0 Wall + 1.0 Finish + 1.3 Live ± 1.25 EQY

11

6.0 Design of Structural Members

6.1 Design Assumptions: Foundation

The Safe Bearing Capacity (SBC) of the soil is taken to be 150 KN/m2. The depth of the foundation is taken as 1.67 m. It is assumed that the soil below is converted to a firm base by sufficient compaction through any convenient means or as directed by the site engineer.

Beam:

The beams are assumed to be rectangular. The preliminary design of the beam is carried out considering the deflection criteria as well as the loading condition.

Slab:

The longest span slab is designed and for uniformity in construction, all the slabs are detailed according to the designed slab. The slab is designed based on IS 456:2000, for adjacent edge discontinuous. However during detailing, the torsion in the free edges is considered.

6.2 Design Methodology:

The design of beams and columns that are the structural components in the building are carried out using the results and analysis for critical responses and also checking with manual calculations is carried out. The design of the foundation is carried out based on the base reactions as obtained from the software with necessary adjustments. The design of slabs and staircases are carried out based on the prevailing design practices, following the codal provisions.

6.2 Calculation of Wall Loads.

The calculations of the loads are given in the following tables:

Load Intensity of Wall 10”Thickness of wall Full wall intensity

12

20% opening Wall intensity

=12.0KN/M 30% opening Wall intensity

=10.5KN/M

5”Thickness of wall Full wall intensity

=7.50 KN/M 20% opening Wall intensity

=6.0 KN/M 30% opening Wall intensity

=5.2 KN/M

Parapet 5”wall Parapet wall

13

7.0 ANALYSIS OUTPUT

Result from Structural models and analysis

14

15

16

17

18

19

20

8.0 Design of Members

Design of Beams and Columns

The design of beams and columns are done from the software itself. However, it is to be notified that the limitations of the design by the software have been evaluated and the adjustments have been made accordingly. The samples (summary) of the design through the software based on IS456: 2000 has been presented hereunder.

Output for the Reinforcement Area (Beams and Columns)

21

Grid –2

22

Grid –4

23

Grid –B

24

Grid –D

25

26

27

9.0 Summary

9.1 Column Design

Different Column Sections and required longitudinal reinforcements are tabulated below: Table 8-1: Column Design Summary

Nod e No Colu mn Column size GF FF Area of rebar % Area of rebar % mm2 inches Req d. Provi ded Req d. Provi ded All C1 9000 0 12”x12 ” 768 1256 1.4 743 904 1 9.2 Beam Design

Two different beam sections used in the buildings are tabulated below. The reinforcement shall be as specified in the drawings.

Table 8-2: Beam Sections

Sn Designation Size Top Rebar Bottom Rebar

1 Beam 10” x 15” -Beam G.F. 10” x 15” 2-16mm Φ(T)+1-12mm Φ(E) 2-16mm Φ(T)+1-12mm Φ(T) -Beam 1st Fl. 10” x 15” 3-12mm Φ(T) 3-12mm Φ(T) 2 Secondary Beam 10” x 13’’ 3-12mm Φ(T) 3-12mm Φ(T) 3 Tie Beam 10” x 13’’ 3-12mm Φ(T) 3-12mm Φ(T)

28

4 Strap Beam

All 12”x18” 4-16mm Φ(T) 2-16mm Φ(T)+1-12mm

Φ(T) 9.3 Slab Design

The final output of the slab is presented below. The construction shall follow the details provided in slab drawing.

Table 8-3: Slab basic data

Slab Thickness 125 mm

Main bars (bottom): Φ8@ 150mm c/c

Main bars (top): Φ8@ 150mm c/c (x-dir)

Φ8@ 150mm c/c (y-dir)

Dist. Bars: Φ8@ 150mm c/c

9.4 Staircase Design

The output of the design of staircase is presented below. The construction shall follow the detail drawing of the staircase.

Table 8-4: Staircase basic data

Staircase Thickness 125 mm

Main bars (bottom): Φ12@ 180mm c/c

Main bars (top): Φ12@ 180mm c/c

Dist. Bars: Φ8@ 150mm c/c

9.5 Footing Design

The output of the design of footing is presented below. The construction shall follow the detail drawing of footing.

Node No. Footing Footing

Size Rebar Concrete Footing Depth Edge Depth Footing Depth From Ground Level Expect 9 F1/F1a 5’0”X5’0” Φ12@ 150mm c/c both direction 16” 8” 5’-6” 9 F2 5’6”X5’6” Φ12@ 150mm c/c both direction 16” 8” 5’-6”

29

ETABS 2016 Concrete Frame Design

Beam Element Details Type: Ductile Frame (Summary)

Level Element Unique Name Section ID Combo ID Station Loc Length (mm) LLRF

Story1 B12 12 Beam 10X15 DCon9 4114.8 4267.2 1

Section Properties

b (mm) h (mm) bf (mm) ds (mm) dct (mm) dcb (mm)

254 381 254 0 25 25

Material Properties

Ec (MPa) fck (MPa) Lt.Wt Factor (Unitless) fy (MPa) fys (MPa)

22360.68 20 1 500 500

Design Code Parameters

ɣC ɣS

1.5 1.15

Factored Forces and Moments Factored Mu3 kN-m Factored Tu kN-m Factored Vu2 kN Factored Pu kN -61.2273 2.014E-06 81.0994 0.9495

Design Moments, Mu3 & Mt Factored Moment kN-m Factored Mt kN-m Positive Moment kN-m Negative Moment kN-m -61.2273 2.962E-06 0 -61.2273

Design Moment and Flexural Reinforcement for Moment, Mu3 & Tu Design -Moment kN-m Design +Moment kN-m -Moment Rebar mm² +Moment Rebar mm² Minimum Rebar mm² Required Rebar mm² Top (+2 Axis) -61.2273 429 0 429 208 Bottom (-2 Axis) 0 215 0 0 215

Shear Force and Reinforcement for Shear, Vu2 & Tu Shear Ve kN Shear Vc kN Shear Vs kN Shear Vp kN Rebar Asv /s mm²/m

30 Shear Ve kN Shear Vc kN Shear Vs kN Shear Vp kN Rebar Asv /s mm²/m 102.1428 42.3655 59.7773 32.5077 465.3

Torsion Force and Torsion Reinforcement for Torsion, Tu & VU2 Tu kN-m Vu kN Core b1 mm Core d1 mm Rebar Asvt /s mm²/m 1.947E-06 81.0941 224 351 0

ETABS 2016 Concrete Frame Design

Column Element Details Type: Ductile Frame (Summary)

Level Element Unique Name Section ID Combo ID Station Loc Length (mm) LLRF

Story1 C11 45 Col 12X12 DCon11 0 3048 1

Section Properties

b (mm) h (mm) dc (mm) Cover (Torsion) (mm)

304.8 304.8 56 30

Material Properties

Ec (MPa) fck (MPa) Lt.Wt Factor (Unitless) fy (MPa) fys (MPa)

22360.68 20 1 500 500

Design Code Parameters

ɣC ɣS

1.5 1.15

Axial Force and Biaxial Moment Design For Pu , Mu2 , Mu3 Design Pu kN Design Mu2 kN-m Design Mu3 kN-m Minimum M2 kN-m Minimum M3 kN-m Rebar Area mm² Rebar % % 108.1482 -3.5558 38.808 2.163 2.163 768 0.83

Axial Force and Biaxial Moment Factors K Factor Unitless Length mm Initial Moment kN-m Additional Moment kN-m Minimum Moment kN-m Major Bend(M3) 0.72327 2667 15.5232 0 2.163 Minor Bend(M2) 0.719478 2667 -2.3899 0 2.163

31

Shear Design for Vu2 , Vu3 Shear Vu kN Shear Vc kN Shear Vs kN Shear Vp kN Rebar Asv /s mm²/m Major, Vu2 23.0033 42.9321 30.3333 19.9266 337.85 Minor, Vu3 18.0388 42.932 30.3333 18.0388 337.85

Joint Shear Check/Design Joint Shear Force kN Shear VTop kN Shear Vu,Tot kN Shear Vc kN Joint Area cm² Shear Ratio Unitless

Major Shear, Vu2 N/A N/A N/A N/A N/A N/A

Minor Shear, Vu3 N/A N/A N/A N/A N/A N/A

(1.1) Beam/Column Capacity Ratio Major Ratio Minor Ratio

N/A N/A

Additional Moment Reduction Factor k (IS 39.7.1.1) Ag cm² Asc cm² Puz kN Pb kN Pu kN k Unitless 929 7.7 1124.0178 309.4535 108.1482 1

Additional Moment (IS 39.7.1) Consider Ma Length Factor Section Depth (mm) KL/Depth Ratio KL/Depth Limit KL/Depth Exceeded Ma Moment (kN-m)

Major Bending (M3 ) Yes 0.875 304.8 6.329 12 No 0

Minor Bending (M2 ) Yes 0.875 304.8 6.295 12 No 0

Notes:

N/A: Not Applicable N/C: Not Calculated N/N: Not Needed

32

DESIGN OF FLOOR SLAB

Design Data

Dimensions of the slab (c/c distance b/w supports), = N/mm2

Length of short span, = m = N/mm2

Length of long span, = m

Width of the supporting beam, = mm

Clear cover to main reinforcement = mm

Assume dia. of reinforcement steel = mm

Calculations

Assume the thickness of slab as mm ; Effective depth, d = mm

Effective span, lx = 4.26699177080158 m (or) 4.138 m whichever is less;d = m

ly = 4.42 m (or) 4.291 m whichever is less; d = m

= < 2 ; Here, (ly / lx) is less than 2, Hence design the slab as two way slab

Load Calculations

Dead Load of slab = 0.125 x 25 = KN/m2 Dust Load on slab = KN/m2

Finishes load on slab = KN/m2 Other load on slab = KN/m2

Live Load on slab = KN/m2

Total Dead load acting on the Structure = KN/m2 Total live load acting on the Structure = KN/m2

Factored Design Load w = KN/m2

Support Condition (Type of panel according to support condition)

For this support condition, Short span coefficient for (ly / lx) = Long span coefficient,

For negative moment, ax = For negative moment, ay =

For positive moment, ax = For positive moment, ay =

Moment Calculation

Max. BM per unit width, = ax w lx

2 _{& = a}

y w lx

2

Ast, req = (0.12/100) bD = mm2

For Short Span, At mid span,

At supports, Provide Y @ mm c/c at midspan &

For Long span, supports for short span (Ast pro. = mm2 )

At mid span, Provide Y @ mm c/c at midspan &

At supports, supports for long span (Ast pro. = mm2 )

Check for Deflection

Percentage of tension reinforcement = %

fs = 0.58 fy (Ast req / Ast pro) =

Refer Fig. 4 of IS 456,

Modification factor =

Allowable (Span / deff ) ratio =

Effective depth required = mm

< d prov. Hence OK 1.04 125 (ly / lx) 3.13 1.20 2.0 4.33 2.0 Ly 20 fck 500 Lx 4.27 fy 230 20 4.291 101 0 0 4.138 9.50 4.42 8 150 Mx My N/mm2 % mm2 1.04, 0.0494 0.047 0.035 KNm Reinforcement details 8

Two Adjacent Edges Discontinuous

0.1695 0.2299 0.0370 Ast , min 150 8 Mu 6.02 171 232 Mu / bd2 0.59 pt 0.79 8.04 7.65 0.88 0.2577 260 335 150 335 5.69 0.66 192 99 148 1.6 41.6 0.33 0.1904

S tr u ct u ra l A n al y si s & D es ig n R ep o rt 3 3 P le ft (X )( u n fa ct o re d ) 3 7 3 .0 0 K N A re a r e q 2 .7 4 K N W id th p ro v 1 .6 8 S o il b e a ri n g 1 5 0 K N /m m 2 T o ta l L e n g th 1 .6 3 C e n t C o l S iz e 0 .3 m p ro v id e d l e n g th 1 .6 7 6 C o rn o r C o l S iz e 0 .3 m L e ft P ro je c ti o n D is t b e tw . C o l. C e n te r to c e n te r m R ig h t P ro je c ti o n C G /f ro m L e ft o f F o rc e 0 M a x P 5 5 9 .5 m N e t u p w a rd s o il p re ss u re = 1 9 9 .1 8 K N /m 2 C h e c k V a lu e 0 .3 m B E N D IN G M O M E N T a b o u t x -x p a ss in g t h ro u g h t h e f a ce o f th e c o lu m n 7 9 .0 1 K N /m m a x im p 0 .0 0 0 d c a lc u la te d f ro m m o m e n ts = 1 3 0 .6 9 m m C h e c k f o r tw o w a y s h e a r o k D = 4 5 0 A st m im .= 7 9 2 .4 1 2 d = 3 9 4 m m m m 2 6 .4 8 9 A st 2 1 7 1 3 9 0 A st 7 9 0 0 8 3 4 3 .6 8 = 0 A st a t b o tt o m 4 6 9 .3 2 m m 2 7 9 2 .4 1 m m 2 1 2 d ia s p a c in g = 2 3 9 .0 0 p ro v id e s p a ci n g =1 5 0 m m G ra d e o f c o n c re te M 2 0 C h e c k fo r o n e w a y sh e a r a t d d is ta n ce ( V u )= 9 8 .1 5 kN N o m in a l sh e a r st re ss (T v )= 0 .1 5 N /m m 2 % o f te n si o n s te e l p = 1 2 d ia 0 .1 9 sh e a r st re n g th o f M 2 0 c o n c re te f o r a b o v e % s te e l = 0 .3 1 O k fo r 1 2 d C h e c k fo r tw o w a y sh e a r c o n c re a te c a p a c it y = 1 2 2 2 8 4 2 .9 7 N F ro m l o a d = 4 6 3 5 6 6 .3 4 N c h e c k o k D e v e lo p m e n t le n g th L d = 6 7 9 .6 9 m m L d a v a ila b le 7 2 8 > 6 7 9 .6 9 O k D e s ig n o f i s o la te d f o u n d a ti o n

34

Project info:

Diwas Kumar Jhimi

Data:

Exterior column load [KN].unfactored = 200 TRUE Interior column load [KN].unfactored = 373.333 .

Load factor = 1

Distance between column center lines[m] = 4.42

Depth of foundation Df [m] = 0.35

Allowable bearing capacity of soil [KN/sq.m] = 150

Width of ext. col. In strap beam direction [m] = 0.3

Width of ext. col. In direct perpendicular strap beam [m] = 0.3

Width of int. col. In strap beam direction [m] = 0.3

Width of int. col. In direct perpendicular strap beam [m] = 0.3

Breadth of strap beam [m] = 0.3

Eccentricity of exterior load from footing [m] = 0.575

R.C designation : Fcu [N/sq.mm] = 20

reinf. Strength : Fy [N/sq.mm] = 500

density of soil [KN/cu.m] 19

Calculation:

reaction of ext.footing R1 229.91 [KN] geo. reaction of ext.footing R1T 240.57 [KN]

Req. ext. footing 1.60 [sq.m] Dim. sq 1.26642

reaction of int.footing R2 343.42 [KN] geo. reaction of int.footing R2T 359.36 [KN]

Req. int. footing 2.40 [sq.m] Dim. sq 1.54781

Use dimensions for ext.footing L= 1.45 [m] Area prov.d 2.10 131% B= 1.45 [m] in strap direction Use dimensions for int.footing L= 1.676 [m] Area prov.d 2.81 117%

B= 1.676 [m] in strap direction check dim TRUE

Design of strap beam:

Breadth of strap beam [m] 0.3

depth of strap beam from shear d 318.43 [mm]

Use depth d 400 [mm] TRUE

total depth H 450 [mm]

fcu = 20 N/smm fy = 500 N/smm

Width = 300mm Max. B.M. Mu‾ = 96kNm

Depth = 400mm Max. S.F. Vu = 171 kN

Mu = 72kNm

K = M/bd2fcu = 0.14 N/mm2 A's required 0.00 mm2

Z = 275.34 mm As required 802.65 Top mm2 As prvd. 100%

As bottom = 500.00 mm2 As provided 803 Top mm2 TRUE

Design shear v = 1.68 N/mm2 Diameter of stirrups 8 mm No. legs 2

Design concrete shear vc = 0.61 N/mm2 Spacing of stirrups reqd. 273mm

35

Design of exterior footing:

Net presure under ext. footing 121.60[KN/sq.m] TRUE

fcu 20 N/smm fy 500 N/smm

Ult. column load 229.91 [KN] Safe bearing capacity 150[KN/sq.m]

Self weight 36.79 [KN] Overburden height -0.2 m A prvd.

Overburden -11.04 [KN] Area of footing reqd. 1.18m2 TRUE

Total load 255.66 [KN] Area of footing provided 2.10m2 L reqd.

Net upward pressure ult. 121.60 [KN/sq.m]Footing thickness 500 [mm] 0.81

Short span Long span B / W

Width B= 1.45m Length L= 1.45m 1.00

Column width 300.00 mm Column breadth 300 mm

Max. cantilever proj. 1.15 m Max. cantilever proj. 0.58 m As min

Max. B.M. /m width 80.41 kNm Max. B.M. /m width 20 kNm 577

K = M/bd2fcu 0.022 N/mm2 K = M/bd2fcu 0.005N/mm2 No. of bars

Z 410.40 mm Z 422 mm 9

As required /m width 450.41 [mm] As required /m width 110[sq.mm] 9

Diameter of bars 12 [mm] Diameter of bars 12 [mm]

Spacing of bars 150 [mm] Number of bars/side 150 [mm] As prvd. TRUE

As provided/m width 754[sq.mm] As provided/m width 754[sq.mm] 167%

688%

Punch shear 0.00 [KN] Dist. to critical section 575 [mm]

Punch shear stress 0.00 [N/sq.mm] Shear force 70 [KN]

36

Design of interior footing:

Net presure under int. footing 134.51[KN/sq.m] TRUE

fcu 20 N/smm fy 500 N/smm

Ult. column load 343.42436[KN] Safe bearing capacity 150[KN/sq.m]

Self weight 44[KN] Overburden height -0.1 m A prvd.

Overburden -10 [KN] Area of footing reqd. 1.74m2 TRUE

Total load 378[KN] Area of footing provided 2.81m2 L reqd.

Net upward pressure ult. 135[KN/sq.m]Footing thickness 450 [mm] 1.04

Short span Long span B / W

Width B= 1.68m Length L=1.68m 1.00

Column width 300 mm Column breadth 300 mm

Max. cantilever proj. 0.69 m Max. cantilever proj. 0.69 m As min

Max. B.M. /m width 32 kNm Max. B.M. /m width 32 kNm 512

K = M/bd2fcu 0.011 N/mm2 K = M/bd2fcu 0.010N/mm2 No. of bars

Z 363 mm Z 374 mm 11

As required /m width 202[mm] As required /m width 196[sq.mm] 11

Diameter of bars 12 [mm] Diameter of bars 12 [mm]

Spacing of bars 150 [mm] Number of bars/side 150 [mm] As prvd. TRUE

As provided/m width 754[sq.mm] As provided/m width 754[sq.mm] 374%

386%

Punch shear 55 [KN] Dist. to critical section 344 [mm]

Punch shear stress 0.024 [N/sq.mm] Shear force 46 [KN]

37

DESIGN OF DOG LEGGED STAIRCASE

Data Internal Dimensions Length = 4.419384 m Width = 2.438281 m Floor Height = 3.047851 m Fck = 20 N/mm2 Fy = 500 N/mm2 Riser = 167.5 mm Tread = 250 mm Landing width = 1142.944 mm Effective Span = 3.1 m

Height of each flight = 1.523926 m

No. of risers in each flight 9.098063 Nos No. of Tread in each flight 8.098063 Nos Design d = 98 mm Required D = 125 mm d = 104 mm Loads DL of waist slab = 3.125 kN/m2 DL on horizontal area = 3.76 kN/m2 DL of steps = 2.09375 kN/m2 LL = 3 kN/m2 FF = 1.2 kN/m2 Total load = 10.06 kN/m2

Factored load = 15.1 (of one flight)

BM and SF Mu = 18 kN-m Vu = 23 kN d from BM consideration 81 mm k = 1.675 pt = 0.432 % Ast = 449 mm2 Main Reinforcement Dia = 12 mm Spacing = 251 mm Distribution Steel Ast = 125 mm2 Dia of bar = 8 mm Spacing = 400 mm Development Length Ld = Ld = (Ø x σs) / (4 x Tbd) Therefore, Ld = 1088 mm Provide, Ld = 1090 mm

38

List of design code and Standards

1. NBC-000-114:1994 : All relevant design codes in Nepal

2. IS 456 – 2000 : Code for practice for plain & Reinforced concrete

3. IS 875 – 1987 : Code of practice for Design Loads (other than Earthquake load for building & structures.

4. IS 1893(part-I)-2002 : Code of practice for earthquake resist design of Structures.

5. IS 13920 – 1993 : Code of practice for Ductile detailing of Reinforced

Concrete structures subjected to seismic forces.

6. SP: 16 – 1980 : Design aids for Reinforced concrete to IS 456 -1978