Myanmar

Engineering
Society

MNBC 2020, Part 3

S AW H T W E Z AW
9 December 2023
M YA N M A R E A R T H Q U A K E C O M M I T T E E
BUILDING ENGINEERING INSTITUTE
Yangon, Myanmar
F E D E R AT I O N O F M YA N M A R E N G I N E E R I N G S O C I E T I E S
 Federation of
Myanmar
Engineering
Society

•MNBC Structural Design follows IBC-2006

and ASCE7-05 codes.

•MNBC started in 2010 and referred

International Codes of 2005-06.

•MNBC tried to combine two codes (IBC

and ASCE7) in order to compile them into
one volume.

•The construction environment in

Myanmar has been changed significantly
since 2010.
• PE system enacted together with Engineering
Council Law.
• Construction quality awareness has raised.
MNBC basic
concepts
 Federation of
Myanmar

Design
Engineering
Society

Supply = Demand
Capacity = Demand
Reaction = Action
Strength = Load

Something just right.

Particular solution.
 Federation of
Myanmar

Design
Engineering
Society

For
General Solution,

Supply > Demand

Capacity > Demand
Reaction > Action
Strength > Load

Something is always more

than required.
 Federation of
Myanmar

Design
Engineering
Society

Rewriting them as,

Supply = FOS x Demand

Capacity = FOS x Demand
Reaction = FOS x Action
Strength = FOS x Load

How much FOS (Factor of Safety) is needed?

 Federation of
Myanmar

Factor of Safety
Engineering
Society

Capacity
Demand
• Capacity = FOS x Demand
 Federation of
Myanmar

Capacity
Demand
ASD vs LRFD
Engineering
Society

• ASD: FOS
• Capacity / FOS = Demand
Soil Spring / 3 = Bearing Capacity

• LRFD:
• Capacity / Reduction = Demand x Load Factor

Capacity
Demand
Reinforcing Steel
Strength Reduction = 0.9
Dead Load Factor = 1.2
RF
LF
Federation of
Myanmar
Engineering
Society
 Federation of
Myanmar
Engineering
Society

Disaster Events

• Normal Buildings
• Life Safety in Big Event
(rare event, MCE, BSE-2N, 2% in 50 years)

• Minor Damage in Small Event

(frequent event, DBE, BSE-1N, 10%in 50 years)

• Important Buildings
• Operational in Big Event
(rare event, MCE, 2% in 50 years)

• No Damage in Small Event

(frequent event, DBE, 10%in 50 years)
Federation of
Myanmar
Engineering
Society
 Federation of
Myanmar

For new buildings,

Engineering
Society
 Federation of
Myanmar

For existing buildings,

Engineering
Society
 Federation of
Myanmar
Engineering
Society

Risk = Hazard x Exposure x Vulnerability

 Federation of
Myanmar
Engineering
Society
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 Federation of
Myanmar
Engineering
Society

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 Federation of
Myanmar
Engineering
Society
MNBC 2020, Part 3, Structural Design Scope

�������ℎ
������ =
������ Code Based Design

Hazard, Load, Safety:

- MNBC 2020
 Strength, Capacity, Member Design:
- Concrete: ACI
- Steel: AISC
- Masonry: Not Yet
- Timber and Bamboo: Not Yet
- Cold-form, Aluminum: Not Yet
 ��������
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Risk and Safety

• RISK, SAFETY, LOAD AND CAPACITY
 Federation of
Myanmar
Engineering
Society
Occupancy Category (will be used as “Risk Category” after ASCE7-10 and later)
Buildings shall be designed according to their “Risk” category

Risk Category

I II III IV

1 10 100 1000 10000 100000

Population
 Federation of
Myanmar
Engineering
Society
Risk Category defined in recent ASCE7-16
Category Occupancy NATURE OF OCCUPANCY
I Low Use or Occupancy of Buildings and Structures Risk Category Buildings and other structures that
represent a low risk to human life in the event of failure.
II Medium All buildings and other structures except those listed in Risk Categories I, III, and IV.

III High Buildings and other structures, the failure of which could pose a substantial risk to human life.
Buildings and other structures, not included in Risk Category IV, with potential to cause a
substantial economic impact and/or mass disruption of day-to-day civilian life in the event of failure.
Buildings and other structures not included in Risk Category IV (including, but not limited to,
facilities that manufacture, process, handle, store, use, or dispose of such substances as hazardous
fuels, hazardous chemicals, hazardous waste, or explosives) containing toxic or explosive substances
where their quantity exceeds a threshold quantity established by the Authority Having Jurisdiction
and is sufficient to pose a threat to the public if released.

IV Essential Buildings and other structures designated as essential facilities.

Buildings and other structures, the failure of which could pose a substantial hazard to the
community.
Buildings and other structures (including, but not limited to, facilities that manufacture, process,
handle, store, use, or dispose of such substances as hazardous fuels, hazardous chemicals, or
hazardous waste) containing sufficient quantities of highly toxic substances where the quantity
exceeds a threshold quantity established by the authority having jurisdiction to be dangerous to the
public if released and is sufficient to pose a threat to the public if released.
Buildings and other structures required to maintain the functionality of other Risk Category IV
structures.
 Federation of
Myanmar
Engineering
Risk Category (Union) Building Type (Union) Society

Apartm
III IV Hut Bungalo
Other
ent
4%3% 1% wSemi-
3%
4%
7%pucca
I Bamboo 7%
40% 37%

II
53% Wood
41%

Cate Apartm Bungalo Semi- All

Risk Category Wood Bamboo Hut Other
gory ent w pucca Buildings

I Temporary 37.40% 2.80% 40.20%

II Medium 6.12% 5.85% 41.20% 53.17%
III High 4.05% 4.05%
IV Ess/Haz 0.45% 0.68% 0.65% 0.80% 2.58%
Union 4.50% 6.80% 6.50% 41.20% 37.40% 2.80% 0.80% 100.00%
 Federation of
Myanmar
Engineering
Societies
Occupancy Category (will be used as “Risk Category” after ASCE7-10 and later)
Buildings shall be designed according to their “Risk” category
Looks similar to Engineering Council Rule PE / RSE work scope
 Federation of
Myanmar
Engineering
Societies

RE RSE
Risk Category PE

I II III IV

1 10 100 1000 10000 100000

Population
 Federation of
Myanmar
Engineering
Society

Load

Strength
Loads
 Federation of
Myanmar
Engineering
Society
Combining Factored Loads Using Strength Design or Load and Resistance
Factor Design
3.2.1.2.2 Basic load combinations
Structures, components, and foundations shall be designed so that their design strength
equals or exceeds the most critical effects of the factored loads in the following
combinations:
1. 1.4 (D + F)
Eq. (3.2.1)
2. 1.2(D+F + T) + 1.6(L + H) + 0.5 (Lr or R) Eq. (3.2.2)
3. 1.2D + 1.6(Lr or R) + (L or 0.8W) Eq.
(3.2.3)
4. 1.2D + 1.6W + L + 0.5(Lr or R) Eq.
(3.2.4)
5. 1.2D + 1.0E + L
Eq. (3.2.5)
6. 0.9D + 1.6W + 1.6H
Eq. (3.2.6)
7. 0.9D + 1.0E + 1.6H
Eq. (3.2.7)
 Federation of
Myanmar
Engineering
Society
Combining Nominal Loads Using Allowable Stress Design or Working Stress
Design

3.2.1.3.1 Basic load combinations

Loads listed herein shall be considered to act in the following combinations; whichever produces the
most unfavorable effect in the building, foundation, or structural member being considered.
Effects of one or more loads not acting shall be considered.
1. D+F
Eq. (3.2.8)
2. D+H+F+L+T
Eq. (3.2.9)
3. D + H + F + (Lr or R)
Eq. (3.2.10)
4. D + H + F + 0.75(L + T) + 0.75 (Lr or R)
Eq. (3.2.11)
5. D + H + F + (W or 0.7E)
Eq. (3.2.12)
6. D + H + F + 0.75(W or 0.7E) + 0.75L + 0.75 (Lr or R) Eq. (3.2.13)
7. 0.6D + W + H
Eq. (3.2.14)
 Federation of
Myanmar
Engineering
Society
Wind Load
Wind Load Characterization
Wind Design Flow Chart- Method 1: Simplified Procedure
ASCE 7-05 Wind Pressures

 The basic form of the pressure equation:

• p = qGC

 Where
 p = a wind pressure on a surface
 q = velocity pressure. This is the pressure due to a moving fluid on
a flat plate
 G = gust factor. The gust factor accounts for dynamic interaction
between the flowing air and the structure
 C = pressure coefficient. The pressure coefficient accounts for
varying pressure across a surface.
 The Velocity Coefficient
2
1 1 0.0765 5280
� = ��2 = �2 = 0.0256�2
2 2 32.2 3600

See ASCE 7-05 C6.5.10

 Atmospheric pressure,
 14.7 pound/square inch,
 2.12 kip/square feet
 or nearly 1 ton/square
feet

 Based on the average

density of air at sea
level, 0.0765
pound/cubic feet
 Velocity Pressure, q
See ASCE 7-05 6.5.10

 qz =Velocity Pressure = 0.00256KzKzt KdV2 I (lb/ft2)

 Constant 0.00256
 V = Basic wind speed in mph
 I = Importance Factor (i.e. different MRI)
 Kz = Exposure Coefficient
 Kzt = Topographical Factor
 Kd = Wind Directionality Factor
 Evaluated at an elevation z:
 qz = 0.00256V2IKzKztKd
 Evaluated at the building mean roof elevation, h:
 qh = 0.00256V2I KhKhtKd
 Federation of
Myanmar
Engineering
Society
Wind Design Flow Chart

Exposure Topography, Kzt Basic Wind Speed

[3.3.6.3] [3.3.5.7] [Table 3.3.1]

Adjustment, λ Velocity Pressure, pS30

pS = λ. Kzt. I. pS30
[3.3.1B] [3.3.1A]

Importance, I
[Table 3.3.2]

Method 1: Simplified Procedure

Minimum Wind Pressure = 10 psf
 Federation of
Myanmar
Engineering
Society
Exposure Factors

Exposure Topography, Kzt Basic Wind Speed

[3.3.6.3] [3.3.5.7] [Table 3.3.1]

Adjustment, λ Vel Pressure, pS30

pS = λ.Kzt. I. pS30
[3.3.1B] [3.3.1A]

Importance, I
[Table 3.3.2]
 Federation of
Myanmar
Engineering
Society
Topography Factor

Exposure Topography, Kzt Basic Wind Speed

[3.3.6.3] [3.3.5.7] [Table 3.3.1]

Adjustment, λ Vel Pressure, pS30

pS = λ. Kzt. I. pS30
[3.3.1B] [3.3.1A]

Importance, I
[Table 3.3.2]
 Federation of
Myanmar
Engineering
Society
Basic Wind Speed

Exposure Topography, Kzt Basic Wind Speed

[3.3.6.3] [3.3.5.7] [Table 3.3.1]

Adjustment, λ Velocity Pressure, pS30

pS = λ. Kzt. I. pS30
[3.3.1B] [3.3.1A]

Importance, I
[Table 3.3.2]
 Federation of
Myanmar
Engineering
Society
Importance Factor

Exposure Topography, Kzt Basic Wind Speed

[3.3.6.3] [3.3.5.7] [Table 3.3.1]

Adjustment, λ Vel Pressure, pS30

pS = λ. Kzt. I. pS30
[3.3.1B] [3.3.1A]

Importance, I
[Table 3.3.2]
 Federation of
Myanmar
Engineering
Society
Wind Pressure

Exposure Topography, Kzt Basic Wind Speed

[3.3.6.3] [3.3.5.7] [Table 3.3.1]

Adjustment, λ Vel
VelPressure,
Pressure,pS30
pS30
pS = λ. Kzt. I. pS30
[3.3.1B] [3.3.1A]

Importance, I
[Table 3.3.2]
 Federation of
Myanmar
Engineering
Society
Earthquake Load
Earthquake Characterization
Earthquake Design Flow Chart
 10
mi
How the earth is made of? n

Section Cut
• Crust – uppermost
thin layer, 3-44
miles thick
• Upper Mantle –
200-250 miles
thick, 1600 ˚F
• Lower Mantle –
1800 miles thick,
7000 ˚F
• Fluid Core – 1,400
miles thick, 7000
Why earthquakes happen?
How do we measure
an earthquake?
MAGNITUDE
• Express in Richter Scale
• Cause
• Size of the event
INTENSITY
• Express in Modified
Mercalli Scale
• Effect
• Damage potential of the
event
MAGNITUDE
• Express in Richter
Scale
• Cause
• Size of the event
• Interest of the
Scientists
INTENSITY
• Express in Modified
Mercalli Scale
• Effect
• Damage potential
of the event
• Interest of the
Engineers
 Ground Shaking,
Federation of
Myanmar
Engineering
Societies

Magnitude, Intensity
Intensity

Magnitude

• Sudden earth shaking applies at the

base of the buildings
 Federation of
Myanmar

Seismic Response
Engineering
Societies
 Federation of
Myanmar

Response Spectrum
Engineering
Societies

Adjust for Building

Period
 Federation of
Myanmar

Seismic Forces
Engineering
Societies

• Apply to each level with respect of its story mass.

• Total story forces = Base Shear

 Federation of
Myanmar
Engineering
Society
Earthquake Design Flow Chart
Ground Acceleration, Soil Data
Building Type
SS, S1 VS,

Risk, Importance, SDS = 2/3 SMS = 2/3 Fa Ss Site Class

I SD1 = 2/3 SM1 = 2/3 Fv S1 SA, SB, SC, SD, SE, SF

Response, R CS = Sa I/R Fa, Fv

Building Weight, V = CS W
W

Design Category,
Seismic Design
SDC

Seismic Design
End
Requirements
 Ground Accelerations
Earthquake Ground
Load Acceleration, Soil Data
Building Type
SS, S1 VS,

Risk, Importance, SDS = 2/3 SMS = 2/3 Fa Ss Site Class

I SD1 = 2/3 SM1 = 2/3 Fv S1 SA, SB, SC, SD, SE, SF

Response, R CS = Sa I/R Fa, Fv

Building Weight, V = CS W
W

Design Category,
Seismic Design
SDC

Seismic Design
End
Requirements
 Ground Accelerations
• Ground Acceleration, SS, S1
Ground Acceleration, Soil Data
Building Type
• Spectral SS, S1
Response Acceleration at 2% ProbabilityVSin
, 50

Years with
Risk, Importance, 5% Critical
SDS = 2/3Damping,
SMS = 2/3 Fa Ss Site Class B Site Class
I SD1 = 2/3 SM1 = 2/3 Fv S1 SA, SB, SC, SD, SE, SF

Ss for 0.2 second

Response, R CS = Sa I/R Fa, Fv
Short Period
Acceleration
Building Weight, for Short Buildings
V = CS W
W
S1 for 1 second
Design Category, Long Period
Seismic Design Acceleration
SDC
for Tall Buildings

Seismic Design
End
Requirements
Ground Accelerations
Spectral Response Acceleration at 2% Probability in 50 Years with
5% Critical Damping, Site Class B

• For buildings,

• oscillation decays at

• 5% critical damping.
 Ground Accelerations
• Site Class

•
SITE Spectral ResponseAVERAGE
SOIL PROFILE Acceleration
PROPERTIESat
IN 2%
TOP 100 feet
CLASS NAME
Shear wave Undrained shear,
Probability in 50 Years with
velocity, v , (ft/s)
5%
SPT,Critical
N
s , (psf)
S u

A Damping,
Hard rockSite Class
v s >B5,000 N/A N/A

B Rock 2,500 > vs > 5,000 N/A N/A

Very dense soil

C 1,200 ≤ vs ≤ 2,500 N > 50 su ≤ 2,000
and soft rock

D Stiff soil profile 600 ≤ vs ≤ 1,200 15 ≤ N ≤ 50 1,000 ≤ su ≤ 2,000

E Soft soil profile v s < 600 N < 15 su < 1,000

Very soft /
F Need further investigation.
 Soil Factors
Earthquake Ground
Load Acceleration, Soil Data
Building Type
SS, S1 VS,

Risk, Importance, SDS = 2/3 SMS = 2/3 Fa Ss Site Class

I SD1 = 2/3 SM1 = 2/3 Fv S1 SA, SB, SC, SD, SE, SF

Response, R CS = Sa I/R Fa, Fv

Building Weight, V = CS W
W

Design Category,
Seismic Design
SDC

Seismic Design
End
Requirements
 Federation of
Myanmar
Engineering
Societies
Soil Factors
Site Class
Spectral Response Acceleration at 2% Probability in 50 Years with 5% Critical
Damping, Site Class B
 SoilCoefficients
Site Factors Fa, Fv

Site Coefficients Fa, Fv

Fa: Site modification factor
Fa: Site for short period,
modification factor
for short period,
ShortShort Buildings
Buildings

Fv: Site modification factor

for long
Fv:period,
Site modification factor
Tall Buildings
for long period,

Tall Buildings
 Design Acceleration, MCE to DBE
Earthquake Ground
Load Acceleration, Soil Data
Building Type
SS, S1 VS,

Risk, Importance, SDS = 2/3 SMS = 2/3 Fa Ss Site Class

I SD1 = 2/3 SM1 = 2/3 Fv S1 SA, SB, SC, SD, SE, SF

Response, R CS = Sa I/R Fa, Fv

Building Weight, V = CS W
W

Design Category,
Seismic Design
SDC

Seismic Design
End
Requirements
•Design Acceleration,
Design MCE to DBE
Spectral Acceleration, SDS, SD1
MCE: Maximum Considered
• SDS = 2/3 Fa Ss Earthquake
(2% probability in 50 years)
• SD1 = 2/3 Fv S1

DBE: Design Basis Earthquake

(10% probability in 50 years)

Reduce MCE to DBE by 2/3

 Earthquake Load
Importance (Risk) Factor
Ground Acceleration, Soil Data
Building Type
SS, S1 VS,

Risk, Importance, SDS = 2/3 SMS = 2/3 Fa Ss Site Class

I SD1 = 2/3 SM1 = 2/3 Fv S1 SA, SB, SC, SD, SE, SF

Response, R CS = Sa I/R Fa, Fv

Building Weight, V = CS W
W

Design Category,
Seismic Design
SDC

Seismic Design
End
Requirements
Importance (Risk) Factor
• Importance Factor, I
 Response (Ductility) Factors
Earthquake Ground
Load Acceleration, Soil Data
Building Type
SS, S1 VS,

Risk, Importance, SDS = 2/3 SMS = 2/3 Fa Ss Site Class

I SD1 = 2/3 SM1 = 2/3 Fv S1 SA, SB, SC, SD, SE, SF

Response, R CS = Sa I/R Fa, Fv

Building Weight, V = CS W
W

Design Category,
Seismic Design
SDC

Seismic Design
End
Requirements
Response (Ductility) Factors
Response Factors: R, Cd, Ω0
R : Response Modification
Cd : Deflection Amplification
Seismic Force Resisting Systems Ω0 : Overstrength
•A Bearing Wall Systems
•B Building Frame Systems
•C Moment Resisting Frame
Systems
•D Dual Systems with SMRS
•E Dual Systems with IMRS
•F Shear Wall – Frame Interactive
Systems
•G Cantilever Column Systems
•H Steel Systems
 Response (Ductility) Factors
Response Factors: R, Cd, Ω0
Seismic Force Resisting Systems
•A Bearing Wall Systems
•B Building Frame Systems
•C Moment Resisting Frame
Systems
•D Dual Systems with SMRS
•E Dual Systems with IMRS
•F Shear Wall – Frame
Interactive Systems
•G Cantilever Column Systems
•H Steel Systems
 Federation of
Myanmar
Engineering
Society
Response (Ductility) Factors

R : Response Modification
Cd : Deflection Amplification
Ω0 : Overstrength
 Seismic Coefficient, Cs
Earthquake Ground
Load Acceleration, Soil Data
Building Type
SS, S1 VS,

Risk, Importance, SDS = 2/3 SMS = 2/3 Fa Ss Site Class

I SD1 = 2/3 SM1 = 2/3 Fv S1 SA, SB, SC, SD, SE, SF

Response, R CS = Sa I/R Fa, Fv

Building Weight, V = CS W
W

Design Category,
Seismic Design
SDC

Seismic Design
End
Requirements
•Seismic Coefficient,
Seismic Base Shear:CVs

• V = CS W

• CS : Response Coefficient

CS = Sa I/R
 Earthquake
Seismic DesignLoad
Category, SDC
Ground Acceleration, Soil Data
Building Type
SS, S1 VS,

Risk, Importance, SDS = 2/3 SMS = 2/3 Fa Ss Site Class

I SD1 = 2/3 SM1 = 2/3 Fv S1 SA, SB, SC, SD, SE, SF

Response, R CS = Sa I/R Fa, Fv

Building Weight, V = CS W
W

Design Category,
Seismic Design
SDC

Seismic Design
End
Requirements
Seismic Design Category, SDC

Seismic Design Category, SDC

SDC with Seismicity .vs. Occupancy

Risk
SDS` SD1 Level of Seismicity I & II III IV

<0.167 g <0.067 g Very Low A A A

0.167 to 0.33 g 0.067 to 0.133 g Low A B C

0.33 to 0.5 g 0.133 to 0.2 g Moderate B C D

>0.5 g >0.2 g High C D D

 Seismic Design Requirements
EarthquakeGround
Load Acceleration, Soil Data
Building Type
SS, S1 VS,

Risk, Importance, SDS = 2/3 SMS = 2/3 Fa Ss Site Class

I SD1 = 2/3 SM1 = 2/3 Fv S1 SA, SB, SC, SD, SE, SF

Response, R CS = Sa I/R Fa, Fv

Building Weight, V = CS W
W

Design Category,
Seismic Design
SDC

Seismic Design
End
Requirements
Seismic Design Requirements
Seismic Design Requirements
Seismic Design Requirements
Seismic Design Requirements
 Federation of
Myanmar
Engineering
Society
Seismic Design Requirements
 Federation of
Myanmar
Engineering
Society
Seismic Design Requirements
 Federation of
Myanmar
Engineering
Societies
Seismic Design Requirements
 Federation of
Myanmar
Engineering
Society
MNBC 2020, Part 3, Structural Design Scope

�������ℎ
������ =
������ Code Based Design

Hazard, Load, Safety:

- MNBC 2020
 Strength, Capacity, Member Design:
- Concrete: ACI
- Steel: AISC
- Masonry: Not Yet
- Timber and Bamboo: Not Yet
- Cold-form, Aluminum: Not Yet
 Federation of
Myanmar
Engineering
Societies
Way Forward

 Adopted in 2020
 Needs
 Corrections
 Typo Errors
 Inappropriate Translations
 Modifications and Adjustments

 Prepare for next update, 2025?



 Thank you.