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PREFACE

The Earthquake of Magnitude 6.1 on September 21, 2009 that caused severe damages to lives andproperties in Eastern Bhutan has re‐confirmed the level of seismic activity taking place in ourcountry. The severity of the earthquake and the repeated recurrence of aftershocks reminded us
all on the existence of geologically active strata upon which our country lies. The event and its
ensuing aftermath have quelled any skepticism on the seismicity of our country and have exposed
the vulnerability inherent in our infrastructures, particularly the houses in rural area and buildings
in urban areas.
While earthquakes cannot be predicted and prevented, our homes could be made stronger,
resilient to shocks and vibrations and therefore safer.
This “Guideline on Proper Construction Practices for Non – Engineered Building –(Stone Masonry)”prepared by the Standards and Quality Control Authority with the financial assistance from UNDP –Bhutan and support from the Department of Disaster Management, MoHCA, provides simple yet
effective “planning and construction techniques” to improve and enhance the resilience toearthquake events of stone masonry houses.
While the measures recommended in the guideline are made with particular focus on stone
masonry construction practices mostly prevalent in our eastern region, the measures could very
well be applied to similar building systems elsewhere.
The Ministry of Works and Human Settlements is pleased to bring out this “Guideline on Proper
Construction Practice for Stone Masonry Building – 2010”. We hope that the users and homeowners find the guideline useful.
The guideline will be periodically reviewed and updated. We welcome any comments and feedback.

Director – SQCA
MoWHS

Hon’ble Zhabtog Lyonpo
Ministry of Works and Human Settlement

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Acknowledgement:This document is prepared with the financial assistance from the UNDP – Bhutan Office andcoordination support from the Department of Disaster Management, Ministry of Home and Cultural
Affairs. Standards and Quality Control Authority would like to thank the two organizations for theirsupport.

The Standards and Quality Control Authority would also like to acknowledge the following
individuals for their valuable inputs in developing this document. Without the support of thesemembers, this guide would not have been possible.
1.
2.
3.
4.
5.
6.
7.
8.
9.

Karma Jamtsho, Department of Urban Development and Engineering Services, MoWHS;
Tshering Dorji, Department of Urban Development and Engineering Services, MoWHS;
Karchung, National Housing Development Corporation;
Jigme Dorji, City Corporation, Thimphu;
Karma Sonam, School Planning and Building Division;
Nagtsho Dorji, DCHS, Department of Culture, MoHCA;
Dechen Tshering, DCHS, Department of Culture, MoHCA;
Junko Mukai, DCHS, Department of Culture, MoHCA;
Sonam Tashi, DCHS, Department of Culture, MoHCA;

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1.

2.

Table of Content
Purpose and Scope .................................................................................................................. 5
1.1

Purpose of the Guideline ..................................................................................................................... 5

1.2

Scope of the guideline ......................................................................................................................... 5

GENERAL ................................................................................................................................. 6
2.1 Layout of the Building ................................................................................................................................ 6
2.2 Site Selection and Foundation ................................................................................................................... 7
2.3 Materials .................................................................................................................................................... 8
2.3.1 Soil Field Test: ..................................................................................................................................... 9

3.

STONE MASONRY WALLS IN MUD MORTAR .......................................................................... 10
3.1 Foundation: ............................................................................................................................................. 10
3.2 Course work ............................................................................................................................................. 10
3.3 Through Stones Details ........................................................................................................................ 11
3.4 Opening in Walls ...................................................................................................................................... 12
3.5 Control on Wall length and Building Height ............................................................................................ 13
3.6 Arrangement of Earthquake resistant elements in single Storey house ................................................. 14
3.6.1 Horizontal Bands in walls................................................................................................................. 14
3.6.2 Horizontal Band at Roof ................................................................................................................... 16
3.7 Vertical Reinforcement in walls ............................................................................................................... 17

4.

STONE MASONRY WALLS USING CEMENT MORTAR .............................................................. 20
4.1 Foundation: ............................................................................................................................................. 20
4.2 Course work ............................................................................................................................................. 20
4.3 Through stones .................................................................................................................................... 21
4.4 Control on Wall Length and Building Height ........................................................................................... 22
4.5 Horizontal Bands in walls with recommended layout of the building. ................................................... 23
4.6 Truss to Band connection ........................................................................................................................ 31
4.6.1 Alternative 1 ..................................................................................................................................... 31
4.6.2 Alternative 2 ..................................................................................................................................... 31
4.7 Vertical reinforcing rods in walls ............................................................................................................. 32
4.7.1 Installation of Vertical Bars: ............................................................................................................. 32

5.

EARTHQUAKE SAFETY TIPS .................................................................................................... 33
5.1 Before an Earthquake .............................................................................................................................. 33
5.2 During an Earthquake .............................................................................................................................. 34
5.3 After an Earthquake ................................................................................................................................ 35

6.

Do’s and Don’ts ..................................................................................................................... 35
6.1 DO’s ......................................................................................................................................................... 35
6.2 DON’Ts ..................................................................................................................................................... 35

7.

References: ........................................................................................................................... 36
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1. PURPOSE AND SCOPE
1.1 Purpose of the Guideline
This guideline aims to provide simple techniques and well established construction practices toimprove the earthquake resisting capacity of non engineered stone masonry buildings.

1.2 Scope of the guideline

The guideline is prepared with particular focus on houses build with stone masonry. It deals withtechniques and good construction practices for stone masonry houses in mud mortar and cement
mortar. The guideline covers those houses which are situated in the earthquake prone zones andwhose bearing walls are built using coursed stone masonry and the number of storey’s are notmore than two.
While significant references have been drawn from the existing appropriate internationallyaccepted codes and guidelines, experiences gained from the observation of the failure and damage
pattern of buildings during the 21st September 2009 earthquake that hit the eastern parts of
Bhutan and from our organizations own engagement in building safety activities has proved very
useful in the preparation of the guideline.
The measures proposed are internationally accepted techniques to improve/enhance theperformance of the buildings during earthquakes. It has to be, however, noted that the measurespresented in the guideline are to be observed as only good construction practices. Expertise of andconsultation with professionals is highly encouraged.

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2. GENERAL
2.1 Layout of the Building
The building should have simple regular and rectangular shape and be symmetrical in both
elevation and plan. The walls and openings should be uniformly distributed in both thedirections as far as possible.
The Length to width ratio should not exceed 3.

Fig. 1: Layout of the Building

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2.2
2 Site Sele
ection and Foundatioongundeer the buildiing has to b
bear the weiight of the hhouse; hence the founddationThe groundmust be built in a strong sooil. Building sshould not be located too
t close too steep slopee andu soil.
should not be built on filled up
d water loggged soil for foundation as the soil can becom
me liquefied (soil turnedd intoAvoid
semi‐‐liquid) in ann earthquakee.

Fig. 2: Example of Bad foundatione selection
Fig. 3: Site

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2.3 Materialsi.

Types of stone:
The common types of stones generally used are natural building stones such as graniteand other igneous rocks, lime stones, sandstones, marble, etc.

ii.

Durability:
All stones shall be free from defects such as cavities, cracks, flaws, patches of soft orloose materials, etc.

iii.

Sizes of stones:
All stones should be small enough to be lifted and placed by hand. The length of thestone shall not exceed 3 times the height and be not less than 200mm. The breadth onbase shall not be greater than ¾ of the thickness of wall nor less than 150mm. The
height of the stone may be up to 300mm and not less than 100mm.

Fig. 4: Dimension of Stoneiv.

Laying of Stones (coursework):
The courses of the stones shall be laid alternately to break the vertical joints and the stones
shall be laid along the grain.

Fig. 5: Stone Coursework
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v.

Mortar:
The mortar should be cement‐sand (1:4), Lime‐Sand (1:3) or clay mud of good quality.
The thickness of mud mortar shall not be more than 30mm and shall be as less as
possible.

vi.

Soil Selection tips for Mud Mortar:
The clay or mixture of clays should preferably conform to the following mechanicalcomposition.
Clay: 18 – 22% by weight
Silt: 40 – 45 % by weight
Sand: 30 – 40% by weight
The total content of clay and silt be preferably not less than 60% by weight.

2.3.1 Soil Field Test:

The following are some of simple field test which can be conducted in the field to identify
the content of sand and clay for ordinary soil. These two simple tests can help you
determine your soil for making mud mortar.
1. Moist cast test. * Compress moist soil by squeezing it in your hand. When you open yourhand, if the soil holds together (that is, forms a cast), pass it from hand to hand — the more
durable the cast, the higher the percentage of clay.
2. Ribbon test. * Roll a handful of moist soil into a cigarette shape and squeeze it between
your thumb and forefinger to form the longest and thinnest ribbon possible. Soil with highsilt content will form flakes or peel instead of forming a ribbon. The longer and thinner the
ribbon, the higher the percentage of clay.
* For these tests, the soil specimen should be gradually moistened and thoroughly reshaped andsqueezed to bring it to its maximum "plasticity" and to remove dry lumps. Do not add too muchwater, as the sample will lose its cohesion.

Fig. 6: Testing soil for mud mortar: the moist cast test (left) and the ribbon test (right)
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3. STONE MASONRY WALLS IN MUD MORTAR
Stone masonry in mud should not be used for community buildings such as schools,
hospitals, etc.
3.1 Foundation:

Fig. 7: Foundation Details
3.2 Course work
The masonry should preferably brought to courses at not more than 600 mm per lift andthickness of the wall = 450 – 500mm (1.5 – 1.65feet)Fig. 8: Maximum height in Single lift and thickness
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Long stones to be used at corners and joints to break the vertical joints and to provide
bonding between perpendicular walls

Fig. 9: Corner Stones
3.3 Through Stones Details

Fig. 10: Through Stones
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3.4 Opening in Walls
Fig. 11: Dimensions of Openings

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3.5 Control on Wall length and Building Height

Height of the Stone masonry walls should be restricted as follows:a. Ceiling height = Maximum 2700 mm or 8.9 feet;b. Span of walls between cross walls = Maximum of 5000 mm or 16.5 feet;
Number of Storeys:a. Maximum of 1 storey if walls are built with lime sand or mud mortar;

Fig 12: Control on length, height and walls in Stone Masonry

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3.6 Arrangement of Earthquake resistant elements in single Storey house
Fig. 13: Provision of Horizontal bands in single storey house

3.6.1 Horizontal Bands in walls

a. Horizontal Band or Ring beams to be provided at sill, lintel
Horizontal band made of timber with two longitudinal runners of 75mm x 38mm (3” by 1.5”)
with splice of 50mm x 30mm (2” by 1.2”) spaced at 500mm (1.6 feet) c/c. The timber bands
will have to painted with anti termite paints and right choice of timber is to be used toprevent from decaying and termite attack.

1.2 feet or
350 mmTimber Band at Plinth and Lintel level
Fig. 14: Band at Corners and intersection

Longitudinal BandmemberSplice member

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Fig. 15: Vertical and Horizontal Bands

Fig. 16: Timber Band details

Fig. 15: Band at Intersection

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Fig. 17: Isometric view of Timber band on stone masonry building

3.6.2 Horizontal Band at Roof

Timber plank 300 mm x 35 mm thick (1’ by 1.4” thick) to be provided on top of wall at roof
level.

Fig. 18: Roof Bands

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3.7 Vertical Reinforcement in walls

Alternative 1:
a. Bamboo reinforcement: 50 mm diameter bamboo rebar provided at wall corners,
intersection corners and intersection of windows and doors openings. The rebar is firmly
anchored in the foundation and goes right up till the roof level. The bamboo may bewrapped in plastic sheet to prevent from decaying.

Fig. 19: At Intersection

Fig. 20: At Corners

Fig. 20: At Corners and intersections
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Alternative 2:
b. Timber Reinforcement: 50mm x 50mm wooden post at wall corners and intersection fixedwith metal strap and nails to the wall, extending all through the building height, firmly
anchored in the foundation. A single unit wooden post to be used as far as possible.
However if joint is necessary dovetail joint as shown in the figure to be used.

Fig. 21: Vertical Reinforcement at CornerFig. 22: Vertical Reinforcement at intersection

Fig. 24: Dovetail joint

Fig. 23: Section
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Alternative 3:

Fig. 25: Vertical Reinforcement at Corner and Intersections

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4. STONE MASONRY WALLS USING CEMENT MORTAR
4.1 Foundation:

Fig. 26: Foundation Details
4.2 Course work
The masonry should preferably brought to courses at not more than 600 mm per lift andthickness of the wall = about 400mm (1.3 feet)Fig. 27: Maximum height in Single lift
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Long stones to be used at corners and joints to break the vertical joints and to provide
bonding between perpendicular walls.

Fig. 28: Corner Stones
4.3 Through stones

Fig. 29: Through stones details
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4.4 Control on Wall Length and Building Height
Height
The height of the coursed‐rubble masonry walls in cement mortar should be restricted asfollows:
9 Two storey;
The ceiling height to be kept 3000 mm (9.8 feet) maximum and span of walls between crosswalls to be limited to 5000 mm (16.4 feet).
Fig. 30: Control on length, height and walls in Stone Masonry(Total length of openings in a wall) / (length of the wall in a room) should not exceed:
Example: (B1 + B2 + B3) / L==

0.55 in single storey
0.42 in 2‐storey

1. Distance of opening from inside corner(B5) more than or equal to 450mm (1.5 feet)
2. Pier width between consecutive openings (B4) more than or equal to 600mm (2 feet)

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4.5 Horizontal Bands in walls with recommended layout of the building.

Fig. 31: Recommended layout of the building with location of Horizontal bands
Building Type 1:

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Building Type 2:

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Building Type 3:

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Fig. 32: Reinforcement & Bending detail in Reinforced Concrete Band

Table 1: Longitudinal rods in RC Bands

Length of wall in room (m)Number of Storey

Diameter (mm)Less than or equal to 5m or 16.4 feet2

12

6m or 19.7 feet2

12Page 29 of 36

Steel Rod 12mm

Steel Band

Fig. 33: Steel in Reinforced Concrete Band

Fig. 34: Reinforced Concrete Band

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4.6 Truss to Band connection –4.6.1 Alternative 1

4.6.2 Alternative 2

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4.7 Vertical reinforcing rods in walls

Fig. 35: Vertical Rods:
4.7.1 Installation of Vertical Bars:

For installations of vertical bars in stone masonry, use of PVC casing pipe of 100mm external
diameter, 600‐750 mm long is recommended around which masonry be built to height 450‐600mm
and the pipe made loose by gently rotating. As the masonry hardens, the pipe is raised and thecavity filled with M20 concrete (nominal mix of 1:1.5:3) and fully compacted by rodding using
12mm diameter and 600mm long bar.
Note:
1. The vertical steel rods should be covered with concrete of M15 grade (1:2:4) or with mortar
1:3 (Cement‐Sand) in suitable pockets around the bars;
1. Keeping the Bar Vertical
Before casting the foundation, the vertical bars must be kept in correct in position
horizontally and vertically. For this purpose tripods may be erected using bamboos or spare
reinforcing bars.

Fig. 36: Keeping the Steel rod vertical
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5. EARTHQUAKE SAFETY TIPS
5.1 Before an Earthquake
•
•
•

•
•
•
•

Ensure that your home is safe. While constructing new buildings, ensure that your building
complies with building and seismic codes.
Teach family members how too turn off electricity, gas and electric supply at the main sources
Practice DUCK, COVER & HOLD. Duck under a sturdy desk or table, hold on, and protect youreyes by pressing your face against your arm. If there’s no table or desk nearby, sit on the floor
against an interior wall.

Ducking in an open doorway,
covering the head (with onehand) and holding onto thedoorway

Ducking in the corner of a
supporting wall, covering
the head and holding on,
if possible

DUCK

COVER

Ducking under a table,
covering the head andholding onto a table leg.

HOLD

Keep list of important telephone numbers to be contacted in case of emergency
Identify likely hazards in and around your school/home/residence. For eg shelves and heavy
objects that may fall during an earthquake, hallways and stairways that may get blocked during
an earthquake.
Convert hazards, wherever possible. For eg: strapping of heavy furniture/cabinets to the wall toprevent toppling, identifying alternative route to leave the room or building.
Prepare a first aid kit, including basic emergency items e g: torches, batteries etc.
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5.2 During an Earthquake
If Indoors

If you are in a
structurally soundbuilding,
stay there.

•
•
•
•
•
•
•
•

If you are inside an
old weak structure,
take the fastest
And safest way out.

If you are near
an exit, leave
the building
as soon as
possible.

After the shaking stops,
take the staircase
to reach open space.

Do not exit the building during the shaking.
Duck, cover and hold.
Face away from windows as the panes may shatter because of the tremor.
Count aloud to 60 seconds earthquakes usually lasts no longer than 60 seconds and counting
would have a calming effect.
As soon as the shaking stops take safest and fastest exit out of the building.
In case if students, do not rush to the exit, get out calmly in an orderly manner.
Do not enter the building as aftershocks may cause parts of the building to collapse.
If you are in a crowded store or other public place, do not rush for exits. Move away fromdisplay shelves containing objects that could fall.

If Outdoors• If you are outside, move to an open area.
• Stay away from power lines, posts, walls and other structures that may fall or collapse.
• If you are driving a vehicle, pull to the side of the road and stop.
• Don not attempt to cross bridges or overpasses which may have been damaged.

Move away from power lines,
posts, walls, false ceiling,
parapet, falling flower pots
and other elements that may
fall or collapse.

Stay away from buildings
with glass panes.

If you are on a steep
hillside, move away
in case of landslides
and falling rocks.

When driving a vehicle
pull to the side of theroad and stop.
Do not attempt to.
cross bridges damaged.

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5.3 After an Earthquake
•
•
•
•
•

STAY CALM!
Check yourself for injuries.
Give first aid as necessary. Help people near you if they are injured.
Move cautiously, and check for unstable objects and other hazards above and around you.
Expect after shocks.

6. DO’S AND DON’TS
6.1 DO’s• Keep heavy objects at lower level, under bed, lower shelfs• Check for fire and, if any, have it controlled.
• Check your water and electrical lines for defects.
• If any damage is suspected, turn the system off from the main valve.
6.2 DON’Ts• Do not keep heavy objects on shelf and cupboard• Do not enter partially damaged buildings. Strong aftershocks can cause further damage
to the buildings and weak structures may collapse.
• Use telephone only for emergency purposes.
• Do not use your two‐wheeler/car to drive around the areas of damage. Rescue
and relief operations need the road for mobility.
• If gas is leaking, do not use matches, flashlights, appliances or electric switches.
• DO NOT PANIC !

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7. REFERENCES:
1. IS 13828: 1993 (reaffirmed edition 2003) – Improving Earthquake resistance of low strength
masonry buildings – Guidelines;
2. IS 1597 (part 1): 1992 (reaffirmed 2002) – Construction of Stone masonry code of practice;
3. IS 4326‐1993 – Earthquake resistant design and construction of buildings – Code of practice;
4. Guideline for earthquake resistance reconstruction and new construction of masonrybuildings in Jammu and Kashmir state: Prof. Anand S. Arya, National Seismic Advisor, GoI –UNDP DRM, Programme, Ministry of Home Affairs, Govt. of India (October 2005);
5. IITK‐BMTPC Earthquake Tips: IIT Kanpur and Building Materials and Technology Promotion
Council, New Delhi, India;
6. Handbook on good building design and construction – Aceh and Nias Islands, International
Strategy for Disaster Reduction, UNDP
7. Earthquake Resistant Construction of Buildings ‐ Curriculum for Mason Training, NSET –Nepal and ADPC, Feb 2005
8. Guidelines for Earthquake Resistant non‐ engineered construction – International
Association for Earthquake Engineering & National Information Centre for Earthquake
Engineering.

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