iN  E  P  A  L      N  A  T  I  O  N  A  L      B  U  I  L  D  I  N  G      C  O  D  E    NBC  202:  2015  GUIDELINES ON:
LOAD BEARING MASONRY

Government  of  Nepal  Ministry  of  Urban  Development  Department  of  Urban  Development  and  Building  Construction  Babar Mahal, Kathmandu, NEPAL

2072    ………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
SecretaryiPrefaceThis Nepal Standard was prepared during 1993 as part of a project to prepare a National Building
Code for Nepal.
In 1988 the Ministry of Housing and Physical Planning (MHPP), conscious of the growing needs of
Nepal's urban and shelter sectors, requested technical assistance from the United Nations
Development Programme and their executing agency, United Nations Centre for Human Settlements(UNCHS).
A programme of Policy and Technical Support was set up within the Ministry (UNDP Project
NEP/88/054) and a number of activities have been undertaken within this framework.
The 1988 earthquake in Nepal, and the resulting deaths and damage to both housing and schools,
again drew attention to the need for changes and improvement in current building construction anddesign methods.
Until now, Nepal has not had any regulations or documents of its own setting out either requirements
or good practice for achieving satisfactory strength in buildings.
In late 1991 the MHPP and UNCHS requested proposals for the development of such regulations anddocuments from international organisations in response to terms of reference prepared by a panel ofexperts.
This document has been prepared by the subcontractor's team working within the Department of
Building, the team including members of the Department and the MHPP. As part of the proposedmanagement and implementation strategy, it has been prepared so as to conform with the general
presentation requirements of the Nepal Bureau of Standards and Metrology.
The subproject has been undertaken under the aegis of an Advisory Panel to the MHPP.
The Advisory Panel consisted of :Mr. UB Malla, Joint Secretary, MHPP Chairman
Director General, Department of Building(Mr. LR Upadhyay) Member
Mr. AR Pant, Under Secretary, MHPP Member
Director General, Department of Mines & Geology(Mr. PL Shrestha) Member
Director General, Nepal Bureau of Standards & Metrology(Mr. PB Manandhar) Member
Dean, Institute of Engineering, Tribhuvan University(Dr. SB Mathe) Member
Project Chief, Earthquake Areas Rehabilitation &Reconstruction Project Member
President, Nepal Engineers Association Member
Law Officer, MHPP (Mr. RB Dange) Member
Representative, Society of Consulting Architectural &Engineering Firms (SCAEF) Member

  
  
  
  
  
………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

ii
Representative, Society of Nepalese Architects (SONA) Member
Deputy Director General, Department of Building,(Mr. JP Pradhan) Member-Secretary
The Subcontractor was BECA WORLEY INTERNATIONAL CONSULTANTS LTD. of New
Zealand in conjunction with subconsultants who included :Golder Associates Ltd., Canada
SILT Consultants P. Ltd., Nepal
TAEC Consult (P.) Ltd., Nepal
Urban Regional Research, USA
Principal inputs to this standard came from :Mr. AM Tuladhar, DoB, HMGN
Dr. AS Arya, Professor Emeritus, University of Roorkee
Mr. YK Parajuli, TAEC
Mr. JR Pokharel, TAEC
Mr. JK Bothara, TAEC
Dr. RD Sharpe, BECA (Team Leader)
Revisions and Updated to this code came from:
Mr. Purna P. Kadariya, DG, DUDBC
Mr. Kishore Thapa, DDG, DUDBC
Mr. Mani Ratna Tuladhar, Sr. Div. Engineer, DUDBC
Mr. Jyoti Prasad Pradhan, Ex. DG, DOB
Mr. Bhubaneswor Lal Shrestha, Ex. DDG, DOB
Mr. Uttam Shrestha, Architect, Architects’ Module Pvt. Ltd.
Mr. Manohar Lal Rajbhandrai, Sr. Structural Engineer, MR Associates
Mr. Amrit Man Tuladhar, Civil Engineer, DUDBC

  
  
  
  
  
  
  
  
  
  
  
  
………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

iii
Preface for revised NBC202:2015 will be written

  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  

………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

iv

Table	  of	
  Contents	
  
0.  

1.  

2.  

3.  

4.  

5.  

Foreword

1  

0.1  

Design Aspect

1  

0.2  

Objective

1  

0.3  

Intended Users

1  

0.4  

Alternative Materials and Construction

1  

0.5  

What are Non-Engineered Buildings

1  

0.6  

Related References

2  

Scope

3  

1.1  

Applicability

3  

1.2  

Limitations

3  Interpretation

7  

2.1  

General

7  

2.2  

Terminology

7  Materials

8  

3.1  

Concrete

8  

3.2  

Brick Masonry

8  Selection and Investigation of the Site

10  

4.1  

General

10  

4.2  

Use of Local Knowledge

10  

4.3  

Site Investigation Requirements

10  

4.4  

Allowable Bearing Pressure

10  General Construction Aspects

12  

5.1  

Plan of Building

12  

5.2  

Footing

13  

5.3  

Openings in Walls

14  ………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

v

6.  

5.4  

Masonry Bond

14  

5.5  

Mortars and Concrete

15  

5.6  

Vertical Joints between Orthogonal Walls

16  Horizontal Reinforcement in Walls

18  

6.1  

Horizontal Bands or Ring Beams

18  

6.2  

Section of Bands

20  

7.  

Dowels at Corners and Junctions

23  

8.  

Vertical Reinforcement in Walls

25  

9.  

Floors and Roofs

27  

9.1  

Pitched Roof:

27  

9.2  

Trussed Roof:

27  

9.3  

Lean to Roof:

27  

9.4  

Timber Flooring/Roofing

29  

9.5  

RCC Roofs and Floors

34  10.   Reinforcement Details for Hollow Block Masonry37  10.1   Horizontal Band:37  10.2   Vertical Reinforcement

37  11.   General consideration for Stone Masonry Buildings

39  11.1   Overall Dimensions

39  11.2   Foundation for Stone Masonry

39  11.3   Openings in Walls

39  11.4   Masonry Bond40  11.5   Mortars and Concrete

41  11.6   Horizontal Reinforcement in the Walls

41  11.7   Vertical Reinforcement in Walls

42  ………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

vi

List of Figures
Figure 1-1: Wall Section and Stone/Brick Wall Footing Details
Figure 5-1: Plan of building blocks
Figure 5-2: Recommendations Regarding Openings in Bearing Walls
Figure 5-3: Strengthening of Masonry around Openings
Figure 5-4: Joints between orthogonal walls
Figure 5-5: Corner walls to be built first
Figure 6-1: Different Bands in Building
Figure 7-1: Junction and Corner-Strengthening by Dowel
Figure 7-2: Detail of T-Junction and Corner Strengthening by Dowel Reinforcement
Figure 8-1: Vertical Reinforcement in Walls
Figure 9-1: Details for Fixing Roofs to Gables and Walls
Figure 9-2: Details of Fixing Keys on Timber Beams
Figure 9-3: Fixing of Joists
Figure 9-4: Fixing of Rafters
Figure 9-6: Details of Improved Mud Roofing
Figure 9-7: Details for Fixing Slates
Figure 9-8: Details for Fixing Clay Tiles
Figure 9-9: Details for Fixing MCR Tiles
Figure 9-10: Details for Fixing CGI Sheets
Figure 9-11: RCC Slab Detail
Figure 10-1: U-Blocks for Horizontal Bands
Figure 10-2: Vertical Reinforcement locations in Cavities
Figure 10-3: Vertical Reinforcement in Cavities
Figure 11-1: Recommended Openings in Load-Bearing Rubble Masonry
Figure 11-2: Random Rubble Masonry with Through-Stones or other bonding elements
Figure 11-3: `Through Stones’ or Bond Elements
Figure 11-4: Vertical Steel in Random Rubble Masonry
Figure 11-5: Vertical Reinforcement in Rubble Stone Masonry………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

5  
12  
14  
15  
16  
17  
19  
23  
24  
26  
28  
29  
30  
31  
32  
33  
33  
34  
34  
36  
37  
38  
38  
40  
41  
42  
44  
44  

1

0.  Foreword
0.1   Design Aspect
Most of the loss of life in past earthquakes in Nepal has occurred due to the collapseof buildings constructed in traditional materials such as brick, stone, wood, mud andadobe and which were not engineered (not designed for structural safety) to be earthquake-resistant. Thus, it is very necessary to introduce earthquake-resistant features in
to non-engineered buildings during their construction.

0.2   Objective
The objective of this Guideline is to achieve anappropriate level of earthquakeresistancein non-Engineered load bearing masonry buildings constructed in Nepal.
Following this Guideline does not rendermasonry buildings able to totally withstandanyearthquake without any appreciable damage. However it is intended to limit thedamage to a level which does not threaten human lives and which can be repaired
quickly. This document includes suitable illustrations to explain the important points,
sketches and sufficient data to proportion the critical strength elements correctly. The
requirements are based on design calculations of typical structures.

0.3   Intended Users
This document is intended to provide necessary guidelines to owners, builders andmasons when a masonry building is to be constructed without engaging professional
engineers. However, professional designers could also use this guideline for an effective
utilisation of their time.

0.4   Alternative Materials and Construction
The provisions of this Guideline are not intended to prevent the use of alternative
materials and methods of construction if such materials and methods are specificallyprescribed by competent professional designers or other competent authorities equivalent
to, or better than, those specified here.

0.5   What are Non-Engineered Buildings
The term non-engineered buildings may be defined as describing those buildings which
are informally constructed in the traditional manner without any input from qualified
Engineersin their design. However, they may follow a set of recommendations derived
from the observed behaviour of such buildings. Unless strengthened (as per thisguideline), such buildings are prone to severe damage inearthquakes inducinggroundshaking of intensity VIII or more on the Modified Mercalli Scale.

………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary20.6   Related References"Guidelines for Earthquake-Resistant Non-Engineered Construction", International
Association for Earthquake Engineering (IAEE), United Nations Educational, Scientificand Cultural Organization (UNESCO) & International Institute of Seismology and
Earthquake Engineering (IISEE), June 2013.
“NBC 109:1994 Masonry: Unreinforced”, Department of Urban Planning and Building
Construction, Kathmandu Nepal, May, 1994.
“IS1905:1987 Code of Practice for Structural Use of Unreinforced Masonry”, Bureau ofIndian Standards, New Delhi, India, 1989.

………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary31.   Scope1.1   Applicability
This Guideline covers load-bearing masonry buildings meeting the criteria specified inclause 1.2. They do not cover wooden buildings, mud buildings (low-strength buildings),
or those constructed in adobe. No attempt should be made to apply these rules to theselatter categories of buildings.
The requirements set forth in this Guideline are applicable only for buildings complying
with the specified limitations. The Guideline only intends to achieve minimum
acceptable structural safety, and it is always preferable to undertake specific calculation
based design. Owners and builders are also encouraged to use the services of competentprofessional designers for better economy and tailor-made detailing. In such cases, therequirements stated here should be construed as advisory.
The provisions of this Guideline should be construed as advisory when undertaking
repairs, alterations and additions necessary for conservation, preservation, restoration,
rehabilitation, reconstruction or continued use of structures of archaeologicalsignificance.

1.2   Limitations
This Guideline is valid (with certain limitations as to span, floor height, etc., asprescribed in Table 1-1) for:i)

Up to two-storied load-bearing brick plus attic (and other rectangular building
units) masonry buildings constructed in cement mortars.

ii)

Up to two-storeyed load-bearing stone masonry buildings plus attic constructedin cement mortar.

iii)

Ordinary buildings (eg. residential, ordinary offices, etc.) with maximum
clearlong span not exceeding 4.5 metres and area of individual floor panel not
exceeding 13.5 square metres(area of floor panel is the clearshort span times theclearlong span of any room/space).

This code is not valid for important buildings which either houses facilities essential
before and after a disaster (eg., hospitals, fire and police stations, communication centres,etc.), or which by its very purpose has to house large numbers of people at one time (eg.,cinema halls, schools, convention centres, etc.), or which has special national andinternational importance (eg., palaces, museums, monuments, temples, etc.), or whichhouses hazardous facilities (eg., toxic or explosive facilities, etc.).
However, these limitations shall not bar anyone wishing to employ qualified professionals to produce an appropriate design. Structures falling outside these limitations will require the appropriate specific design as required by the territorial authority in which they
are to be located.
………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

4

Table 1-1: Buildings Size limitations

Floor

Min. Wall
Thickness(mm)

Max. Height(m)Max. shortspan of Floor(m)

Two storied construction
Attic

230

3.2

3.5

First

230

3.2

3.5

Ground

350

3.2

3.5

Attic

350

3.0

3.2

First

350

3.0

3.2

Ground

350

3.0

3.2

Load-BearingBrick
Masonry in Cement Mortar

Load-Bearing Stone
Masonry in Cement Mortar

One storied construction
Load-BearingBrick
Masonry in Cement Mortar

Ground

230

3.2

3.5

Load-Bearing Stone
Masonry in Cement
MortarGround

350

3.0

3.2

NOTE: In two storied constructions, the walls in the firststorey shall be exactly above the wallsin the groundstorey and the thickness of wall in the firststorey shall not be greater thanthat in the groundstorey.
The cantilever-projection of roof/floor, where provided, shall not exceed 1m. No loadbearing wall shall be constructed over such cantilever projections.
See Figure 1-1also.

………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

5

Figure 1-1: Wall Section and Stone/Brick Wall Footing Details………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary6………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary72.   Interpretation
2.1   General
2.1.1

In this Guideline, the word `shall' indicates a requirement that is to be adopted inorder to comply with the provisions of this document, while the word `should'
indicates recommended practice.

2.1.2

Words implying the singular only also include the plural and vice versa wherever
the context requires this.

2.2   Terminology
In this Guideline, unless inconsistent with the context, the following definition shallapply:

REINFORCEMENT:(i)   High Strength Deformed Bars – Fe500: High strength deformed bars with fy =500 N/mm² and minimum elongation not less than 14% (Fe500 Grade).
(ii)   High Strength Deformed Bars – Fe415: High strength deformed bars with fy =415 N/mm² and minimum elongation not less than 14% (Fe415 Grade).
(iii)   Mild Steel Bars: Mild steel bars with fy = 250 N/mm² and minimum elongation
not less than 20%.

Note: NS191-2046 and NS84-2042 can be referenced for the reinforcement
specifications.

………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary83.   Materials
3.1   Concrete
The concrete to be used in footings, columns, beams, slabs and other horizontal andvertical reinforcements in wall (bands, dowels, etc.) shall be of at least M20 Grade;i.e.have a minimum crushing strength of 20 N/mm2 (or 20 mpa) when a 150 mm cube istestedin 28 days.
Note: Where adequate care has been taken in the following: the selection of materials;
mixing; correct proportioning; proper placing; compacting and curing of theconcrete, a nominal mix of 1:1.5:3(cement : coarse sand : coarse stoneaggregate) is expected to produce M20 grade concrete. However water-cement
ratio shall not exceed 0.6 (i.e. not more than 30 litres of water per 50kg of
cement shall be used).

3.2   Brick Masonry
All brick masonry shall be built in a tradesman-like manner using the best practices andworkmanship that include:•

Pre-soaking of bricks in water•

Level bedding planes fully covered with mortar•

Vertical joints broken from course to course and filled fully with mortar

Bricks: The bricks shall be of a standard rectangular shape, burnt red, hand-formed or
machine-made and shall conform to the Nepal Standard NS: 1/2035. Bricks used asmasonry units shall be of class A1 or class B1 as per NS: 1/2035 with compressive
strength as specified in clause5.5.

Wall Thickness: Minimum wall thickness has been specified in clause 1.2 (Table 1-1).
A minimum thickness of one half-brick (or 110 mm) and a maximum thickness of one
brick (or 230 mm) shall be used for the walls constructed as non-load bearing walls inthese buildings.

Mortar: Mortar used in load-bearing walls of masonry buildings shall be as specified inclause5.5. The addition of small quantities of freshly hydrated lime to the mortar in alime-cement ratio of ¼:1 to ½:1 will increase its plasticity greatly without reducing its
strength.
Plaster: All plasters shall have a cement-sand mix not leaner than 1:6 on outside or
inside faces. It shall have a minimum 28 days cube crushing strength of 3 N/mm2.
………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

9Thick plaster is not desirable but a minimum plaster thickness of 10 mm shall be adopted.

………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary104.   Selection and Investigation of the Site
4.1   General
This section sets out some of the requirements to be considered during site selection forthe construction of buildings in order to minimise the risks to the buildings from primarygeological as well as secondary seismic hazards such as fault rupture, landslides andliquefaction. A building shall not be constructed if the proposed site is:-

Water-logged-

A rock-falling area-

A landslide-prone area-

A subsidence and/or fill area-

A river bed or swamp area

4.2   Use of Local Knowledge
It is a good practice during the construction of a building to examine the existing local
knowledge and the history of the performance of existing buildings. This will assist in
identifying whether there is any danger from inherent natural susceptibilities of the land
to the processes of sliding, erosion, land subsidence and liquefaction during the pastearthquakes or any other natural/geological processes likely to threaten the integrity ofthe building. The local practice of managing such hazards, if any, should be judged
against the required level of acceptable risk.

4.3   Site Investigation Requirements
Site exploration shall be carried out by digging test pits, two as a minimum, and more if
the subsurface soil condition shows a significant variation in soil type.
Generally, the minimum depth of exploration for a building covered by this Guideline
shall be 2 m. In hilly areas, exploration up to the depth of sound bed-rock, if it lies
shallower than 2 m, should suffice.
No exploration shall be required if the site is located on rock or on fluvial terraces (Tar)with boulder beds. The soils encountered in the test pits should be classified as perTable
4-1.

4.4   Allowable Bearing Pressure
The allowable bearing pressure that can be used is given in Table 4-1in conjunction withthe visual classification of the subsurface soil type.

………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

11
Table 4-1: Classification of Foundation Soil and Safe Bearing Capacity

Type of Foundation Materials

Foundation
Soil Classification

Presumed Safe
Bearing
Capacity,
KN/m2

1.

Rocks in different state of weathering, boulder
bed, gravel, sandy gravel and sand-gravel mixture,dense or loose coarse to medium sand offeringhigh resistance to penetration when excavated bytools; stiff to medium clay which is readily
indented with a thumb nail.

Hard³ 2002.

Fine sand and silt (dry lumps easily pulverised by
the fingers); moist clay and sand-clay mixture
which can be indented with strong thumb pressure.

Medium< 200 and³ 1503.

Fine sand, loose and dry; soft clay indented withmoderate thumb pressure.

Soft< 150 and³ 1004.

Very soft clay which can be penetrated several
centimetres with the thumb, wet clays.

Weak

<100

Buildings can be constructed on hard, medium and soft soils, but it is not recommended to constructbuildings on weak soils. Hence, appropriate soil investigations should be carried out to establish theallowable bearing capacity and nature of soil and if required, various measures can be adopted for improvement of bearing-capacity of soils.

………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary125.   General Construction Aspects
5.1   Plan of Buildinga) Symmetry: The building, as a whole or its individual blocks, shall be planned to be
as close to symmetrical as possible.
b) Regularity: Buildings of simple rectangular shapes behave better in earthquakes
than irregular buildings with projections. To avoid
torsional effects which arepronounced in long narrow rectangular blocks, length of a block shall not be greater than
three times its width. If longer lengths are required, it should be divided into two (ormore if the length desires so)separate blocks with sufficient separation.

Figure 5-1: Plan of building blocks………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

13c) Separation of Blocks: Separation of a large building into several blocks
may be required so as to obtain symmetry and regularity of each block. For preventing hammering or pounding damage between blocks a physical separation of
40 to 50mm shall be provided through out the height of the building above theplinth level.
The separation can be treated just like an expansion joint or it may be filled or
covered with a weak material which would easily crush and crumble during
earthquake shaking.

d) Simplicity: Ornamentation involving large cornices, vertical or horizontal
cantilever projections, facia stones, etc. where used must be reinforced with steel,which shall be properly embedded or tied into the main structure of the building.

5.2   Footing
The building must be well connected to the foundation and the earth. While selecting aproper site or evaluating the suitability of a given site, clause 4 shall be followed.
The footing should be provided at a depth below the zone of deep freezing in cold regions
and below the level of shrinkage cracks in clayey soils but not less than 800 mm for one
storey building and not less than 900mm for two storey building.
The minimum dimensions for footing in soft soil shall be as perFigure 1-1. For other soil
types, the footing dimension shall be taken as per Table 5-1.
Table 5-1: Base width of footings
Masonry
Type

Brick

Stone

Minimum base width (mm) of wall footNo of Sto- ing for soil type:reySoftMedium
Hard
Two

900

650

550

One

650

550

450

Two

*

800

600

One

800

600

600

*:Two-storied buildings with load-bearing stone masonry of random rubble orhalf-dressed stone are not recommended in soft soil.

………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary14

5.3   Openings in Walls
Any opening in the wall should be small in size and centrally located. The following are
the guidelines for the size and position of openings.
i)   Openings are to be located away from inside corners by a clear distance equal to atleast 1/4 of the height of the opening, but not less than 600 mm.
ii)   The total length of openings in a wall is not to exceed 50 % of the length of the wall
between consecutive cross-walls in single-storey construction, 42 % in two-storey
construction.
iii)   The horizontal distance (pier width) between two openings is to be not less than one
half of the height of the shorter opening (seeFigure 5-2), but not less than 600 mm.
iv)   The vertical distance from one opening to another opening directly above it shallnot be less than 600 mm, nor less than one half the width of the smaller opening see
Figure 5-2v)   When an opening does not comply with requirements (i) to (iv), it shall be boxed inreinforced jambs through the masonry (Figure 5-3).
vi)   If the vertical opening of the wall is more than 50 % of the wall height, vertical bars
shall be compulsorily provided in the jambs.

Figure 5-2: Recommendations Regarding Openings in Bearing Walls

5.4   Masonry Bond
In order to achieve the full strength of masonry, the usual bonds specified for masonryshall be followed so that the vertical joints are broken properly from course to course.

………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary15

5.5   Mortars and Concrete
Where steel reinforcing bars are provided in walls, the bars shall be embedded in a
cement concrete mix of at least M20 grade (refer clause 3.1). The mortar for brickmasonry shall not be leaner than 1:6 in any case.
Table 5-2: Brick and Mortar specification for different building
No ofStoreyFloor

Proportion ofingredients for mortar(cement: sand)Min. crushingstrength of bricks(N/mm2)

First

1:6

3.5

Minimum
brick wall
thickness
(mm)
230

7.5

230

5

350

3.5

230

2

1

Ground

1:6

Ground

1:6

Figure 5-3: Strengthening of Masonry around Openings………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary16

5.6   Vertical Joints between Orthogonal Walls
For convenience of construction, builders prefer to make a toothed joint which is later
often left hollow and weak. If the joint (connection) between orthogonal walls is not lost
during lateral forces such as those inducedby earthquakes, the building will tend to act asa box and its resistance to lateral forceswill be much larger than the resistance offered byindividual walls with lost connection (or broken joint).
To obtain full bond, it is necessary to make a sloped or stepped joint. It should beconstructed so as to obtain full bond by making the corners first to a height of 600 mm,
and then building the wall in between them. Alternatively, the toothed joint shall bemade in both the walls alternately in lifts of about 450 mm, as shown in Figure
5-4andFigure 5-5.

Figure 5-4: Joints between orthogonal walls………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

17

Figure 5-5: Corner walls to be built first………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary18

6.   Horizontal Reinforcement in Walls
Horizontal reinforcing of walls is required in order to tie orthogonal walls together, to confine
the masonry units against spalling during earthquakes and to avoid greater reduction in loadcarrying capacity of walls.

6.1   Horizontal Bands or Ring Beams
The most important horizontal reinforcing is by means of reinforced concrete bands
provided continuously through all load-bearing longitudinal and transverse walls at
plinth, lintel and roof eave levels, and also at the top of gables according to therequirements stated below.

6.1.1   Plinth Band
This should be provided in all masonry buildings. It may also serve as a damp-proof
course. Plinth bands are more important in soft or uneven soils. Reinforcement as given
in Table 6-1 shall be provided in a plinth band.

6.1.2   Sill BandA continuous sill band shall be provided through all walls below openings (especially,
just below windows). It should be provided in all storeys in all buildings.

6.1.3   Lintel BandA continuous lintel band shall be provided through all walls just above openings. Thus
the top-level of all the openings (doors and windows) shall be at the same line as far aspracticable. Lintel bands must be provided in all storeys in all buildings as per Table 6-1.
Additional reinforcement may be required to be provided over openings to distributeloads to the walls on the sides of the openings.

6.1.4   Dowel Band (Stitches)This band shall be provided where dowel-bars are required as specified in section 7.

6.1.5   Roof Band / Floor Beam
Roof band shall be provided at the eave-level of trussed roofs (Figure 8-1) and also justbelow the joists on all such floors which consist of joists and covering elements (flexible
floors), so as to integrate them properly at their ends and fix them into the walls.
Floor beam shall be constructed monolithically with RCC slab over all bearing walls
when RCC slab is provided. Reinforcement as given in Table 6-1 shall be provided inthis band.

………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary19

6.1.6   Parapet Band
This band shall be provided at the top of parapet walls, where parapet walls areconstructed. Similar to sill band, it shall be continuous over all parapet walls andreinforced as per Table 6-1.

6.1.7   Gable Band
Masonry gable ends must have the triangular portion of masonry enclosed in a band, thehorizontal part of which will be continuous with the eave-level band on the adjacent longitudinal walls (Figure 8-1). It is advantageous to replace gable masonry wall with atruss covered with light-weight materials.

Figure 6-1: Different Bands in Building………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

20

Figure 8-1: Overall Arrangement of Reinforcing Masonry Buildings

6.2   Section of Bands
The width of the RC band shall be the same as the thickness of the wall. The vertical
thickness of the RC band may be kept to a minimum of 75 mm where two longitudinalbars are required and at least 150 mm where four longitudinal bars are required. The
thickness of the band shall be made closely equal to, or a multiple of, the thickness ofmasonry unit.
The minimum steel requirements for various buildings for these bands or ring beams areshown in Table 6-1. Additional bars may be required where the band is carrying anyother additional loads such as masonry loads above openings. A cover of 25 mm fromthe face of wall shall be maintained for all steel reinforcements. Full continuity of steel
shall be provided around corners and through junctions.
The longitudinal bars shall be held in position by steel stirrups or links of at least 6 mm
in diameter spaced 150 mm apart. Stirrups or links shall be made of high strength deformed bars-Fe415 or Mild steel bars. The concrete mix shall be of at least M20 Grade.
………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

21
Table 6-1: Requirement for steel in RC BAND
Band /Beam

RC band minimum
thicknessMin.
No. Ofbars

Min. Diameterof Bars (mm)Plinth150mm*1

4

12

Sill

75mm

2

10

75mm*2212

210(top)212(bottom)

75mm *32

12300mm *3

4

12

75mm

2

8

Lintel150mm*2

Roof

Dowel (Stitch)

Note: *1: Plinth band thickness can be reduced to 75mm reinforced with 2-12mm dia bars incase of hard soil.
*2: Where opening width does not exceed 1.25m and masonry height above opening
does not exceed 0.9m, 75mm thick lintel is sufficient. In such lintels, longitudinal reinforcement shall be placed maintaining 25mm cover from bottom. For opening width up
to 2m and masonry height above opening upto1.2m, 150mm thick lintel band is necessary.
*3: Roof band of at least 75mm thickness shall be provided where flexible floor/roof (eg.
timber floor) rests. For RCC roof/floor, 300mm deep RCC beam (including slab) castmonolithically with slab, shall be provided.
The specified bar number and diameter are for High Strength Deformed Bars-Fe415.
For bars of other grades specified in clause 2.2, reinforcing bars should be provided toform the same steel area as in the Table.
Additional 8mm dia. longitudinal bars shall be provided at the middle of each layer ifthe
width of the wall exceeds 250 mm such that spacing of these bars do not exceed 250mm.

………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

22

Figure 8-2: Reinforcement in RC Bands………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary237.   Dowels at Corners and Junctions
Steel dowel bars shall be used at corners and T-junction to integrate the box action of walls.
Dowels are to be taken into the walls to a sufficient length so as to provide their full bondstrength.
Dowels shall be provided in 75 mm thick concrete (M20 Grade) bands at a vertical spacing of
500 -700 mm. The size and layout of the bars in dowel band are shown in Figure 7-1 and Figure
7-2.

Figure 7-1: Junction and Corner-Strengthening by Dowel………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

24

Figure 7-2: Detail of T-Junction and Corner Strengthening by
Dowel Reinforcement………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary25

8.   Vertical Reinforcement in Walls
Vertical steel bars shall be installed at the critical sections like corners of walls and junctions ofwalls right from the foundation concrete. They shall be covered with cement concrete in cavities
made around them during the masonry construction (see Figure 8-1). This concrete mix should
be kept to M20 Grade or richer (refer clause 3.1).
The vertical steel may also be required at jambs of the openings (refer clause5.3), which shallstart from the foundation and may be terminatedby embedding it into the lintel band (or roof
band/beam), but the vertical steel at the corners and junctions of walls must be taken into either
the floor and roof slabs or the roof band.
The recommended amount of vertical reinforcing steel for brick masonry is given in Table 8-1.

Table 8-1: Vertical Steel Requirement at Critical Sections for Brick MasonryNo. of
Storeys

One
Two

Floor

Diameter of high strength deformed bars-Fe 415
single bar in mm for :at each critical section

at jambs of opening(where required)

Ground

12

12

First

12

12

Ground1612Note: Equivalent diameter reinforcement can be used for reinforcement grades otherthan Fe415 specified in clause 2.

………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

26

Figure 8-1: Vertical Reinforcement in Walls………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary27

9.   Floors and Roofs
As a general rule, heavy floors and roofs are source of seismic hazard. Hence, roofs as well as
floors should be made as light as possible structurally and functionally.

9.1   Pitched Roof:
Pitched roofs may be trussed, with the top of the walls generally at one level - except
for the masonry gables at the ends of the building. Alternatively, the longitudinal andcross-walls may be raised to varying heights up to the roof slope and the rooms
spanned by rafters and purlins. From a seismic design point of view, the trussed arrangement is preferable, particularly for school buildings.

9.2   Trussed Roof:In trussed roofs, all trusses shall be supported on the eave or roof-band. Where atrussed roof adjoins a masonry gable, the ends of the purlins shall be carried on andsecured to a plate securely bolted to the band at the top of gable-end masonry (Figure
9-1).
Gable triangles are very weak when loaded perpendicular to their plane and may faileven in small earthquakes. Hence, all trusses shall be sufficiently braced to transmit
the lateral forces from the roof to the appropriate cross walls. Also, where possible,
gable walls should be made of light weight materials.

9.3   Lean to Roof:
All masonry walls shall be topped by a reinforced concrete roof-band securely held bymeans of bolts. Alternatively, wall plates may be used which are bolted to the bandand to which the rafters and purlins are fixed (Figure 9-1).

………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

28Top  chord  of  roof  truss

Bottom  chord  anchoredto  plate

25 30

70

30 25

230

Anchor  plate
Roof  sheeting
Purlin  anchored  to  plate
Gable  wall  plate
Gable  wall  plate  anchor

Gable  band

Reinforcement  lapped  of  junction  of  gable  and  eaves  bandEaves  band(a) Roof Fixing Details at Gables
Top  chord

Bottom  chord

Eaves

INTERMEDIATE  TRUSS  FIXING

Gable  band

Purlin  anchor  to  plate

Barge  board

Plate
Gable  plate  anchoredAnchor  plate  to  eaves  bandEaves  band

Gable  band

GABLE  END  DETAILLEAN  TO  ROOF  FIXING  DETAIL(b) Roof Fixing Details at Walls
Figure  11.2  :  Details  for  Fixing  Roofs  to  Walls

Figure 9-1: Details for Fixing Roofs to Gables and Walls………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary29

9.4   Timber Flooring/Roofing
Where timber flooring or roofing is provided, following provisions shall be followed.

9.4.1   Structure
The following points shall be duly considered when selecting the materials for flooring
structures:a.   Locally available hardwood species, preferred to soft wood species,
shall be used for the structural elements of flooring.
b.   Using a whole tree trunk as a structural element not only increases
the weight, but also makes the wood more susceptible to termite
attack. This results in a shorter life for such elements. Hence, only
sawn timbers shall be used.
c.   Seasoned and treated timber or bamboo shall be used. Simple
methods of treating and seasoning timber and bamboo are given in
Appendix 1. These shall be carried out prior to the placement ofthese structural elements.

9.4.2   Beams and Bearings
Beams shall never rest directly on a wall and shall rest on roof band.
The beam shall be long enough to extend beyond both the supporting
walls. Timber keys shall be provided on both the external and internal
walls as shown in Figure 9-2.

Figure 9-2: Details of Fixing Keys on Timber Beams
The beams shall be rectangular in section and shall never be laid wider
surface horizontal. The minimum dimensions of the beams for different
spans shall be as tabulated in Table 9-1.
………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

30

Table 9-1: Size of Beams (mm) for Various Spans
Size (DxB) for SPAN of
SPECIES2m

2 to 2.5 m

2.5 to 3 m

3 to 3.5 m

Hardwood

190x100

220x100240x120270x140

Softwood

230x120270x140

310x150

340x160

Spacing
(mm)

<450

<450

<450

<450

9.4.3   Joists and Rafters
Joists/rafters shall be long enough to extend beyond supporting members
such as walls and/or beams. The extended joists/rafters shall have timber keys on both external and internal sides of the supporting elements
as shown in Figure 9-3 and Figure 9-4.

Figure 9-3: Fixing of Joists………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

31

Figure 9-4: Fixing of Rafters
The joists/rafters shall be rectangular in section and shall never be laidwith their wider surface horizontal. The minimum sizes of joists/rafters
for various spans considering 1” plank shall be as tabulated in Table 9-2.
Table 9-2: Minimum Size (mm) of Joists and Rafters
Dimension (DxB) FOR SPAN UPTOSPECIES

1m

1.5 m

2m

2.5 m

3m

Hardwood

100*65100*65100*65

120*65130*75

Softwood

140*75

140*75

140*75

170*90180*90Spacing (c/c)

≤0.5m

≤0.5m

≤0.5m

≤0.5m

≤0.5m

9.4.4   Floor Finishing
It is preferable to use better bridging materials between the joists toachieve stiffer flooring. Timber planks and half-cut bamboo are examples of these. The fixing shall be carried out as illustrated in Figure 9-5.
The mud layers used for the floor base and the finish shall not be morethan 75 mm thick in total.

………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

32

X

A  LAYER  OF  POLYTHENE  SHEET

50

75  mind

50  min.

d/2

MUD

HALF-­CUT  BAMBOO  PLACED  ADJACENT

Wall  Plate
Mud  WallWOODEN  JOISTELEVATION
MUD
A  LAYER  OF  POLYTHENE  SHEETHALF-­CUT  BAMBOO  PLACED  ADJACENTWOODEN  JOISTLASHING  (  String,  G.I.Wire,  Bamboo  )SECTION  AT    X-­X

Figure 9-5: Details of Fixing Bridging Materials to Joists

Figure    9.8  :      Details  for  Fixing  Bridging  Materials  to  Joist  and  Rafters

9.4.5   Roof Coverings
9.4.5.1  Mud

Mud is widely used in the north-western parts of Nepal. The
general techniques practised for making mud roofs consume
high quantities of mud, resulting in heavy buildings. Mudroofs shall be constructed as illustrated in Figure 9-6.

Figure 9-6: Details of Improved Mud Roofing………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

33

9.4.5.2  SlatesThin slates shall be preferable to thicker ones. Slates shall beof uniform size. They shall be nailed to purlins and laid with aminimum overlapping of 75 mm to prevent leaking. The details illustrated in Figure 9-7 shall be adopted for slate roofing.

Figure 9-7: Details for Fixing Slates

9.4.5.3  Clay Tiles

Well-burnt, good-quality clay roofing tiles shall be used forroofing. All the tiles shall be well-anchored on the battens.
The details given in Figure 9-8 shall be adopted for fixing clay
tiles

Figure 9-8: Details for Fixing Clay Tiles

9.4.5.4  MCR Tiles

Micro concrete roofing (MCR) tiles are becoming popular inmany parts of the country. These tiles have projected binding
wires embedded into the tiles for anchoring. All the tiles shallbe properly tied with these protruding wires to the battens andpurlins, as shown in Figure 9-9.

………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

34

Figure 9-9: Details for Fixing MCR Tiles

9.4.5.5  CGI Sheets

Corrugated galvanised iron (CGI) sheets are very popular in
all parts of the country, except in the high mountains. These
sheets shall be properly anchored to each purlin/batten that
supports them. The details are illustrated in Figure 9-10.

Figure 9-10: Details for Fixing CGI Sheets

9.5   RCC Roofs and Floors
Since RCC slabs are rigid for in-plane deformation, they are preferred for floors and roofs.
RCC slab and beam shall be cast directly over the walls. Hence, all walls shall be raised
to the required height before casting the RCC Slabs. The concrete used for RCC slab orslab and beam shall be at least M20 Grade as defined in clause 3.1.
Following provisions are specified for the reinforcement inRCC slabs with at least twoedges continuous and maximum short span not exceeding 3.5m:………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

35
i)  

The thickness of slab shall be at least 115mm. However the thickness shall not
exceed 125mm.

ii)  The reinforcement shall be provided with high strength deformed bars (withminimum yield strength of 415N/mm2) of at least 8mm diameter.

iii)   The spacing between bottom reinforcing bars shall not exceed 150mm in both
directions.
iv)   At a discontinuous edge, at least 50% of the bottom bars (i.e. every alternate bars)
shall be extended to the supports and remaining bars can be curtailed at a distanceof 0.15 times the span in that direction from the support.
v)  At a continuous edge, at least 50% of the bottom bars shall be continued to the next
panel and remaining bars can be curtailed (or bent-up to form top bars) at distanceof 0.25 times the span in that direction from the support.

vi)   The spacing between the top bars shall also not exceed 150mm.
vii)   At a discontinuous edge, additional top bars equal to at least 50% of the bottom
bars shall be provided (or 50% of the bottom bars can be U-hooked to act as topbars) up-to a distance of 0.1 times the span in that direction.
viii)   At a continuous edge, at least 50% of top bars shall extend up to a distance of 0.25
times the span in that direction from the support. Remaining bars can be extended
only up to a distance of 0.15 times the span in that direction (or it may be acontinuity of bent-up bottom bars).
ix)   At edges, top bars running parallel to edges might be kept at spacing of 200 mm up
to width of 0.2 of span in the direction perpendicular to the bar.
Above stated reinforcement detailing guidelines are only for general cases. Where
larger span is required or a special case exists, it shall be designed by competent professionals.

………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

36

Figure 9-11: RCC Slab Detail………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary37

10.   Reinforcement Details for Hollow Block Masonry
The following details shall be followed in placing the horizontal and vertical steel in hollow
block masonry using cement concrete blocks.

10.1   Horizontal Band:

150

Reinforcement bands as explained in clause 6.2 can be provided to block masonry also.
U-shaped blocks as shown in Figure 10-1can be used for easier construction of the horizontal bands at various levels of the storey.
The amount of horizontal reinforcement shall be taken same as that given in Table 6-1.
If U-blocks are used in sill/lintel bands, then the reinforcements shall be taken 25% morethan that given in Table 6-1and may be provided by using four longitudinal bars and 6
mm diameter stirrups. But the reinforcement in these bands need not be more than four
number of 12 mm bars.

Figure 10-1: U-Blocks for Horizontal Bands
10.2   Vertical Reinforcement
The vertical bars specified in Table 8-1 shall be located conveniently inside the cavitiesof the hollow blocks, one bar to each cavity. Where more than one bar is planned, thesecan be located in two or three consecutive cavities, as shown in Figure 10-2. The cavities containing bars are to be filled by using a concrete mix of at least M20 Grade, andare to be properly rodded for compaction.
To avoid the need to lift blocks too high, the bars are made shorter and lapped with upper bars. This is wasteful of steel and has a second disadvantage that the capacity to develop sufficient bond strength in small cavities remains doubtful. To solve this problem,
the two alternatives shown in Figure 10-3 may be used:
the use of three sided or U-blocksor slotted blocks bent interlocked bars………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

38

30  Ø

30  Ø

30  Ø

Figure 10-2: Vertical Reinforcement locations in Cavities

30  Ø

Ø

(  a  )
Ø(  a  )(  b  )

Figure 10-3: Vertical Reinforcement in Cavities(  b  )………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary39

11.   General consideration for Stone Masonry Buildings
11.1   Overall Dimensions
The height of stone buildings constructed to this Guideline is restricted to two
storeys only. Nevertheless, two-storied buildings with load-bearing stone masonry of
random rubble or half-dressed stone are not recommended in soft soil.However, an attic
floor may also be used within the building.
The inter-storey height may be kept as low as 2.5 metres, but not more than that specified in Table 1-1. The maximum unsupported length of a wall (long wall) between crosswalls shall be limited 4.5 metres. For longer walls, buttresses shall be used at intermediate points not further apart than three metres. Each buttress shall have a minimum thickness equal to the thickness of wall it supports, base width not less than one-sixth of thewall height and top width not less than the thickness of the wall it supports.

11.2   Foundation for Stone Masonry
The foundation for stone masonry walls shall follow clause 4,clause 5.2and Figure 1-1.

11.3   Openings in Walls
Openings should be as small and as centrally located as practicable. The required limits
on opening size are shown in Figure 11-1. Ventilators, where used, shall be 450 x 450
mm or smaller.
Tops of openings in a storey should preferably be at the same level, so that a continuous
horizontal band can be provided over them that includes the lintels throughout the building.
The horizontal distance between two openings shall not be less than one-half of theheight of the shorter opening.
The vertical distance between openings one above the other shall not be less than
600 mm.

………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

40

Figure 11-1: Recommended Openings in Load-Bearing Rubble Masonry

11.4   Masonry BondRandom rubble masonry construction should be constructed in lifts of not more than
600 mm.
Through-Stonesof a length equal to the full wall thickness should be used in every 600
mm lift at not more than 1.2 m apart horizontally. If full-length stones are not available,
pairs of stones, each not less than three-quarters of the wall thickness long shall be usedin place of one full-length stone so as to provide an overlap between them (see Figure11-2 and Figure 11-3).

………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

41

Figure 11-2: Random Rubble Masonry with Through-Stones or other bonding elements

Alternatively, steel hooked link or S-shaped tie can be used by embedding it in cementconcrete mix of at least M20 Grade with minimum thickness of 75 mm. Long stones
shall also be used at corners and junctions of walls to break the vertical joint pattern andto provide bonding between adjacent walls.

11.5   Mortars and Concrete
Where steel reinforcing bars are provided, the bars shall be embedded in cementconcrete mix not leaner than M20 Grade. Mortars used for stone masonry shall not beleaner that 1:6.

11.6   Horizontal Reinforcement in the Walls
All the horizontal reinforcing recommended in clause 6(recommended for brick masonry) shall be used for random rubble construction as well.

………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

42

Figure 11-3: `Through Stones’ or Bond Elements

11.7   Vertical Reinforcement in Walls
The amount of vertical reinforcement required to be provided in masonry walls at thecorners and T-junctions and at jambs of openings is shown in
Table 11-1………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

43

Table 11-1: Required Vertical Steel at Critical Sections for Stone Masonry

No of Storey

Floor

One
Two

Dia. of single Fe-415 bars at each at:
Critical section

Jamb of opening

Ground

12

12

First

16

12

Ground1612

Notes: High strength deformed bars-Fe500 or High strength deformed bars-Fe415 as
per section 2.2 shall be used as vertical reinforcement
Two-storied buildings with load-bearing stone masonry of random rubble
or half-dressed stone are not recommended in soft soil.

The installation of a vertical bar in stone masonry can easily be executed by using about
750mm long and 75 mm diameter pipe casing around which the masonry is built to aheight of 600 mm. The pipe is kept loose by rotating it during masonry construction.
Then the casing is raised up and the cavity filled around the bar with concrete of M20
grade as shown in figures 17.1 and 17.2. The concrete will not only provide a bond between the steel and the masonry, but it will also protect the bar from corrosion.
The jamb steel shall be taken from the footing up to the lintel band (or roof band) andanchored into it.

………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary

44

Figure 11-4: Vertical Steel in Random Rubble Masonry.

Figure 11-5: Vertical Reinforcement in Rubble Stone Masonry………………………

………………..

………………

.…………………..

………………….

Ganesh Karmacharya
Engineer

Parikshit Kadariya
SDE

Mani R. Gelal
DDG

Ramesh Pd. Singh
DG

Arjun K. Karki
Secretary