A

REPORT
ON
STRUCTURAL ANALYSIS AND DESIGN OF

Prepared For

Prepared By
Roshan Kejariwal
Structural Engineer
NEC no-14859 civil A

Submitted To
 TO WHOM IT MAY CONCERN

This report comprises the summary of the structural design of Roof truss Building. The report consists of
design procedures adopted, assumptions made, and the input assign in the design. During design it is
assumed that the client will completely followed the architectural as well as the structural design. It is
also assumed that the construction will be supervised by a professional engineer.
The designer will not be responsible if any alteration or change to the structural system is made by the
client or contractor without the prior permission from the designer, or the alteration to the 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 the design weight of the floor and the total weight.
The design calculations and derivations are limited to only to let the concerned people know the
methodology adopted. However, the calculation may be provided to the client or the concerned
authorities when needed, upon request.

………………………….

(DESIGNER)
Introduction
General
This report presents the structure analysis and design of Truss Building. The building is Special Moment
Resisting Frame steel type of building. It is designed to meet both strength and serviceability
requirements when subjected to gravity and earthquake loads.

The analysis and design has been based on IS codes that are in practice in Nepal. This report consists of
the design assumptions, design methodology, design inputs and outputs, and sample design of
structural members.

Salient Features
Project Information
Type of building : Residential

Location : Sindhuli

Building Features
The building has some special features which are listed below:

Type of Building : Steel Truss Building

Shape : Regular Rectangular Shape

Plinth level : As per architectural drawing

Roof floor Type : Inaccessible, Terrace

Walls : Brick walls on ground floor

Footing Type : Isolated footing

Depth of foundation : Min 5ft below ground level or as per site condition

Story Height : 12’ (center to center)

Total Height : 15’2”

No of Story : 1 storey
Figure 1: Modeling in Etabs
 Load Calculation

[IS875:1987
Dead Load
Pt.1]
GI Sheeting = 0.060 kN/m2
Fixings = 0.025 kN/m2
Services = 0.100 kN/m2
Total Load = 0.185 kN/m2
load on purlin = 0.165 kn/m

[IS875:1987
Imposed Load
Pt.2]
Live Load = 0.63 kN/m2
load on purlin = 0.56 kN/m

Wind load

BUILDING DAT A
LENGTH OF THE BUILDING 11.88 meters ROOF SLOP E 1 : 3.5
WIDTH OF THE BUILDING 7.01 meters WIND SP EED 47 m/s
EAVE HEIGHT 3.6 meters TERRAIN CATEGORY 1
BAY SP ACING 3.96 meters BUILDING CATEGORY C

BUILDING P ERMEABILITY CONDITION MEDIUM(B/W 5% TO 20 %) (OF WALL AREA)

LOADING ON F RAME ME MBE RS
(NOTE: ALL VALUES IN KN/m)

7.01 5.36 5.36 7.01

Y 1.03 LOAD 4.12 -4.12 LOAD -1.03

CASE 1 CASE 2

1.86 0.21
0.21 1.86

6.18 LOAD -1.03 1.03 LOAD -6.18

Y CASE 3 CASE 4

X
 6.69 6.69 1.54 1.54

LOAD LOAD
Y -5.15 CASE 5 5.15 0.00 CASE 6 0.00

K1 K2 K3 INTERNAL PRESSURE CO-EFFICIENT

1.00 0.99 1.00 0.5
H/W 0.51 0.5<h/w≤1.5 GCpi
DESIGN WIND VELOCITY 46.53 m/s L/W 1.69 1.5<l/w≤4 -0.5
WIND PRESSURE 1.300 kN/m²

CLICK ON '+' ON THE LEFT TO VIEW ( STADD USER CAN COPY THE DETAILS SHOWN BELOW IN STADD EDITOR FOR REFERENCE)
(+i) TRANSVERSE WIND PRESSURE
GCPe (GCPe - GCPi) WIND LOAD
LEFT WALL 0.700 0.20 x1.3x3.96= 1.03 kN/m (pressure)
LEFT ROOF -0.862 -1.36 x1.3x3.96= -7.01 kN/m (suction)
RIGHT ROOF -0.540 -1.04 x1.3x3.96= -5.36 kN/m (suction)
RIGHT WALL -0.300 -0.80 x1.3x3.96= -4.12 kN/m (suction)

(-i) TRANSVERSE WIND SUCTION

GCPe (GCPe - GCPi) WIND LOAD
LEFT WALL 0.700 1.20 x1.3x3.96= 6.18 kN/m (pressure)
LEFT ROOF -0.862 -0.36 x1.3x3.96= -1.86 kN/m (suction)
RIGHT ROOF -0.540 -0.04 x1.3x3.96= -0.21 kN/m (suction)
RIGHT WALL -0.300 0.20 x1.3x3.96= 1.03 kN/m (pressure)

(+i) LONGITUDINAL WIND PRESSURE

GCPe (GCPe - GCPi) WIND LOAD
LEFT WALL -0.500 -1.00 x1.3x3.96= -5.15 kN/m (suction)
LEFT ROOF -0.800 -1.30 x1.3x3.96= -6.69 kN/m (suction)
RIGHT ROOF -0.800 -1.30 x1.3x3.96= -6.69 kN/m (suction)
RIGHT WALL -0.500 -1.00 x1.3x3.96= -5.15 kN/m (suction)

(-i) LONGITUDINAL WIND SUCTION

GCPe (GCPe - GCPi) WIND LOAD
LEFT WALL -0.50 0.00 x1.3x3.96= 0.00 kN/m (suction)
LEFT ROOF -0.80 -0.30 x1.3x3.96= -1.54 kN/m (suction)
RIGHT ROOF -0.80 -0.30 x1.3x3.96= -1.54 kN/m (suction)
RIGHT WALL -0.50 0.00 x1.3x3.96= 0.00 kN/m (suction)
 Fig: Load Combinaton

[Grab

Knee bracing Tie bar

 Fig: Typical Truss

Truss Sections
1. Top chord= ISNB 90M

2. Bottom chord = ISNB 90M

3. Bracings = ISNB 40M

4. Purlin= ISNB 65M

5. Column= ISNB 150M

6. Tie bar = ISNB 50M 2 in number

7. Knee bracing near columns= ISNB 50M

Truss Design
ETABS 2016 Steel Frame Design
IS 800:2007 Steel Section Check (Strength Summary)

Element Details (Part 1 of 2)

Level Element Unique Name Location (m) Combo Design Type Element Type Section
Story1 B81 141 0.4445 UDStlS3 Beam Special Moment Frame ISNB90M

Element Details (Part 2 of 2)

Classification Rolled
Class 1 Yes

Design Code Parameters

ɣM0 ɣM1 An /Ag LLRF PLLF Stress ratio Limit
1.1 1.25 1 1 0.75 0.95

Section Properties
A (m²) Izz (m⁴) rzz (m) Ze,zz (m³) Av,z (m²) Zp,zz (m³) Iyz (m⁴) It (m⁴)
0.0012 0.000001 0.03449 0.000029 0.0008 0.000029 0 0.000003

J (m⁴) Iyy (m⁴) ryy (m) Ze,yy (m³) Av,y (m²) Zp,yy (m³) Iw (m⁶) h (m)
0.000003 0.000001 0.03449 0.000029 0.0008 0.000029 0.1016

Material Properties
J (m⁴) Iyy (m⁴) ryy (m)
0.000003 0.000001 0.03449

E (kN/m²) fy (kN/m²) fu (kN/m²)

210000000 250000 410000

Stress Check Forces and Moments

Location (m) N (kN) Mzz (kN-m) Myy (kN-m) Vy (kN) Vz (kN) To (kN-m)
0.4445 -43.993 -0.2007 0.0023 0.9037 0.0264 0.0054

PMM Demand/Capacity (D/C) Ratio 9.3.2.2(a)

D/C Ratio = P / Pdy + Ky * Cmy * (My,span / Mdy; ) + KLT *
(Mz,span / Mdz; )
0.266 = 0.173 + 0.002 + 0.093

Basic Factors
Buckling Mode K Factor L Factor L Length (m) KL/r
Major (z-z) 1 1 0.889 25.775
Major Braced 1 1 0.889 25.775
Minor (y-y) 1 1.907 1.69545 49.157
Minor Braced 1 1.907 1.69545 49.157
LTB 1 1.907 1.69545 49.157

Axial Force Design

N Force Td Capacity Nd Capacity Pdy Capacity Pz Capacity Pd Capacity
kN kN kN kN kN kN
Axial -43.993 279.5455 279.5455 254.7821 274.3502 254.7821
 Tdg Tdn Ncr,T Ncr,TF An /Ag N /Nd
kN kN kN kN Unitless Unitless
279.5455 363.096 99346.1201 1055.0011 1 0.157

Design Parameters for Axial Design

Curve α fcc (kN/m²) λ Φ χ fcd (kN/m²)
Major (z-z) a 0.21 3119710.16 0.283 0.549 0.981 223048.94
MajorB (z-z) a 0.21 3119710.16 0.283 0.549 0.981 223048.94
Minor (y-y) a 0.21 857724.46 0.54 0.681 0.911 207139.96
MinorB (y-y) a 0.21 857724.46 0.54 0.681 0.911 207139.96
Torsional TF a 0.21 857724.46 0.54 0.681 0.911 207139.96

Moment Designs
M Moment Mspan Moment Md(yield) Capacity Mdv Capacity Mnd Capacity Md(LTB) Capacity
kN-m kN-m kN-m kN-m kN-m kN-m
Major (z-z) -0.2007 -0.6117 6.5455 6.5455 6.5137 6.5455
Minor (y-y) 0.0023 0.0141 6.5455 6.5455 6.5137

Curve αLT λLT ΦLT χLT C1 Mcr (kN-m)

LTB a 0.21 0.078 0.49 1 2.37 1183.3652

Cmy Cmz CmLT kz ky KLT My / Mdy Mz / Mdz α1 α2

Factors 1 0.475 1 1.013 1.059 0.998 3.591E-04 -0.031 2 2

Shear Design
V Force (kN) Vd Capacity (kN) To Capacity (kN-m) Stress Ratio Status Check
Major (y) 0.9037 102.7476 0.0054 0.009 OK
Minor (z) 0.0264 102.7476 0.0054 2.565E-04 OK

Shear Design
Vp (kN) kv (Unitless) ΛW (Unitless) Τb (kN/m²)
Reduction 102.7476 0 0 1

End Reaction Major Shear Forces

Left End Reaction (kN) Load Combo Right End Reaction (kN) Load Combo
0.8617 UDStlS3 0.9458 UDStlS3
 Column Design

ETABS 2016 Steel Frame Design

IS 800:2007 Steel Section Check (Strength Summary)

Element Details (Part 1 of 2)

Level Element Unique Name Location (m) Combo Design Type Element Type Section
Story1 C3 164 0 UDStlS2 Column Special Moment Frame ISNB150M

Element Details (Part 2 of 2)

Classification Rolled
Class 1 Yes

Design Code Parameters

ɣM0 ɣM1 An /Ag LLRF PLLF Stress ratio Limit
1.1 1.25 1 1 0.75 0.95
 Section Properties
A (m²) Izz (m⁴) rzz (m) Ze,zz (m³) Av,z (m²) Zp,zz (m³) Iyz (m⁴) It (m⁴)
0.0024 0.000008 0.05668 0.000094 0.0015 0.000094 0 0.000016

J (m⁴) Iyy (m⁴) ryy (m) Ze,yy (m³) Av,y (m²) Zp,yy (m³) Iw (m⁶) h (m)
0.000016 0.000008 0.05668 0.000094 0.0015 0.000094 0.1651

Material Properties
J (m⁴) Iyy (m⁴) ryy (m)
0.000016 0.000008 0.05668

E (kN/m²) fy (kN/m²) fu (kN/m²)

210000000 250000 410000

Stress Check Message - KL/r > 180 (IS 3.8, Table 3)

Stress Check Forces and Moments

Location (m) N (kN) Mzz (kN-m) Myy (kN-m) Vy (kN) Vz (kN) To (kN-m)
0 -11.2448 0 0 -0.674 -0.0514 0

PMM Demand/Capacity (D/C) Ratio 9.3.2.2(a)

D/C Ratio = P / Pdy + Ky * Cmy * (My,span / Mdy; ) + KLT *
(Mz,span / Mdz; )
0.6 = 0.501 + 0.005 + 0.099

Basic Factors
Buckling Mode K Factor L Factor L Length (m) KL/r
Major (z-z) 2.361 0.836 3.0576 127.387
Major Braced 0.787 0.836 3.0576 42.48
Minor (y-y) 7.035 0.972 3.556 441.417
Minor Braced 0.977 0.972 3.556 61.282
LTB 7.035 0.972 3.556 441.417

Axial Force Design

N Force Td Capacity Nd Capacity Pdy Capacity Pz Capacity Pd Capacity
kN kN kN kN kN kN
Axial -11.2448 550 550 22.4304 230.0978 22.4304

Tdg Tdn Ncr,T Ncr,TF An /Ag N /Nd

kN kN kN kN Unitless Unitless
550 714.384 195461.5561 25.7417 1 0.02

Design Parameters for Axial Design

Curve α fcc (kN/m²) λ Φ χ fcd (kN/m²)
Major (z-z) a 0.21 127722.43 1.399 1.605 0.418 95081.74
MajorB (z-z) a 0.21 1148546.62 0.467 0.637 0.934 212351.79
Minor (y-y) a 0.21 10637.06 4.848 12.739 0.041 9268.75
MinorB (y-y) a 0.21 551897.31 0.673 0.776 0.86 9268.75
Torsional TF a 0.21 10637.06 4.848 12.739 0.041 9268.75
 Moment Designs
M Moment Mspan Moment Md(yield) Capacity Mdv Capacity Mnd Capacity Md(LTB) Capacity
kN-m kN-m kN-m kN-m kN-m kN-m
Major (z-z) 0 2.0608 21.4 21.4 21.4 20.8688
Minor (y-y) 0 0.1832 21.4 21.4 21.4

Curve αLT λLT ΦLT χLT C1 Mcr (kN-m)

LTB a 0.21 0.31 0.56 0.975 1.364 245.163

Cmy Cmz CmLT kz ky KLT My / Mdy Mz / Mdz α1 α2

Factors 0.6 0.994 0.932 1.006 1.011 0.999 0 0 2 2

Shear Design
V Force (kN) Vd Capacity (kN) To Capacity (kN-m) Stress Ratio Status Check
Major (y) 0.674 202.1538 0 0.003 OK
Minor (z) 0.0514 202.1538 0 2.543E-04 OK

Shear Design
Vp (kN) kv (Unitless) ΛW (Unitless) Τb (kN/m²)
Reduction 202.1538 0 0 1
BASE PLATE DESIGN

Base Plate Design

Length of column,D 150 mm
Width of column 150 mm
Factored Load 25 kN
concrete grade 20 Mpa
bearing strength of concrete 9 Mpa
2777.77
Required area of plate 8 mm2
Asuume width 250 mm
11.1111
Calcuated Length 1 mm
Provided Length 250 mm
Base plate thickness assumed 12 mm
bearing pressure from concrete 0.4 N/mm2
Cantilever length 50 mm
Moment 500 Nmm
6545.45
Moment capacity of base plate/mm 5 ok

Weld Checks
Load 50% 12.5 kN
Column flange with gusset plate,weld
length 600 mm GUSSET HEIGHT
Weld size 5 mm
662.817
Weld strength 6 N/mm
18.8588
Required Length of weld 9 ok

Base plate and gusset,connection length 200 mm

Weld size 5 mm
662.817
Weld strength 6 N/mm
18.8588
Required Length of weld 9 ok
GUSSET REQUIREMENTS
T 8 mm
h1 150 mm
h2 100 mm
permissible slant length 108.8 mm
103.077
actual length 6 mm ok

FOOTING AND ANCHOR BOLT DESIGN

Design of Foundation

Design Condition
Material Properties
Characteristic Strength of concrete, fck (adopt) = 20 MPa
Characteristic strength of rebars, fy (adopt) = 500 MPa
CLASS
Anchor bolt, fy = 250 MPa
4.6
kN/
Allowable bearing pressure on soil = 120
m2
Required depth of footing bottom below ground level = 1.5 m
kN/
Unit Weight of soil below backfill = 18
m3

Loads on Foundation (from Etabs analysis)

factored unfactored
Compression (kN) 24 16
Tension/Uplift (kN) 51 34
Shear at Column base (kN) 5 5
Moment (kNm) 0 0

Column Base Plate

Column width as per design = 150 mm
A base plate of 250 x 250 x 12 mm shall be used.
N/
Allowable bearing pressure of concrete = 5.00
mm2

Development Length of Anchor Bolts

 Anchor bolts are placed at an offset of 40 mm from the face of base plate
Then,
Total Tension in the anchor bolts = 9.97 kN
If a total of 4-
mm-φ bolts be used, then,
20
Tension in each bolt = 4.98 kN
Net area of a 20 mm-φ bolt = 245 mm2

Bolt capacity =0.9Anbfub/1.25 = 70.57 kN

So,
Development length required1 from pull out = 101.2 mm
Development length required2 from bond = 947.0 mm
Hence final ld = 947.0 mm
Embed the anchor bolts 946.97 mm in the concrete.

Design of Pedestal
0.3
A pedestal of 0.30 x x 1.50 m shall be used.
0

Check for Uplift

Self-weight of pedestal = 3.375 kN
Self-weight of footing+ soil = 29.1 kN
Deducting the uplift force, Net downward load = -1.525 kN
Pedestal in tension

For combo I,
19.37
Net downward load = kN
5
Moment at the base of pedestal due to shear = 7.5 kNm
Total Moment at base of pedestal = 7.5 kNm
Then,
19.37
Design Compression = kN
5
Design Moment = 7.5 kNm

𝑃_𝑢/ 𝑀_𝑢/
0.016 and 0.021
(𝑓_𝑐𝑘 (𝑓_𝑐𝑘
𝑏𝐷)= 𝑏𝐷^2 )=
For Fe500 and d'/D = 0.19 ,
𝑝/ 0.01 => p = 0.20
𝑓_𝑐𝑘
=
Area of Longitudinal reinforcement required = 720 mm2
(checked against a minimum of %
0.8 [IS456:2000 Cl.26.5.3.1]
0.8%) )
Diameter of bars = 12 mm
Clear cover = 50 mm
 No. of bars required = 8

Provide 8 - 12 mm dia bars.

Again,
Use tie diameter = 8 mm
Spacing of ties shall be least of:
i) least lateral dimension = 300 mm
16 times main bar
ii) = 192 mm
dia.
iii
48 times tie dia. = 384 mm
)
iv
300 mm
)
Provide spacing = 190 mm

Provide 8 mm dia lateral ties @ 190 mm c/c.

Design of Footing
Direct Load from pedestal, W1 = 19.38 kN
Moment from pedestal = 5.00 kNm

Try a footing: 1.00 x 1.0 x 0.30 m

Weight of footing, W2 = 7.5 kN

Weight of soil above footing, W3 = 24.57 kN

Then,
Total Vertical Load = 51.45 kN
Overturning Moment = 9.00 kNm

Eccentricity of resultant vertical force = 0.17 m > 𝑏 = 0.17 m

/
Therefore,
6
Base pressure distribution is triangular with part of the footing lifting up.
Width of footing in contact with soil = 0.98 m
Now,
kN/ kN/ kN/ O
Maximum pressure = 105.45 < 1.25 x 120 = 150
m2 m2 m2 K

kN/
Pressure ordinate at the face of pedestal = 67.65
m2

kN/
Downward pressure due to self-weight of soil and concrete = 34.5
m2
Then,
Length of foundation slab off the face of pedestal = 0.35 m
 kNm/
Factored BM about the face of pedestal = 4.59
m
Diameter of bars = 12 mm
Clear Cover = 75 mm
Effective depth required = 41.53 mm
O
Effective depth provided = 219 mm
K
Area of steel required = 263 mm2
(checked against minimum reinforcement of 0.12% )
Spacing required = 430 mm
Spacing provided = 150 mm

Provide 12 mm dia bars @ 150 mm c/c on top and bottom both ways.

Check for Punching Shear

Vertical Load as of Load Combo I = 16.00 kN
10800
Area resisting punching shear = mm2
0
N/
Punching shear stress developed = 0.15
mm2
N/ O
Permissible shear stress = 1.12
mm2 K

No shear reinforcement is needed.

References
 NBC Nepal Building Code
 IS 800:1998
 Limit State Design of Substructure- Swamisharan
 ETABS manual V 16