## Tag Archives: masonry

### Nepal building codes

Files in the archive:

preeti.ttf
NBC101 material specification.pdf
NBC000 requirements for state-of-the art design an introduction.pdf
NBC102 unit weight of materials.pdf
NBC105 seismic design of buildings in nepal.pdf
NBC107 provisional recommendation on fire safety.pdf
NBC108 site consideration for seismic hazards.pdf
NBC109 masonry unreinforced.pdf
NBC110 plain and reinforced concrete.pdf
NBC111 steel.pdf
NBC112 timber.pdf
NBC113 aluminium.pdf
NBC114 construction safety.pdf
NBC201 mandatory rules of thumb reinforced concrete buildings with masonry infill.pdf
NBC202 mandatory rules of thumb load bearing masonry.pdf
NBC203 guidelines for earthquake resistant building construction low strength masonry.pdf
NBC204 guidelines for earthquake resistant building construction earthen building (eb).pdf
NBC205 mandatory rules of thumb reinforced concrete buildings without masonry infill.pdf
NBC206 architectural design requirements.pdf
NBC207 electrical design requirements for (public buildings).pdf
NBC208 sanitary and plumbing design requirements.pdf

Latest verion can be downloded from http://www.dudbc.gov.np/building.php

### Elementary analysis for width/height ratio of retaining masonary structure

As we know that masonry structure cannot resist tension, hence all the lateral force should be resisted by its weight component only. In this article we will derive expression for width/height ratio for a simple rectangular masonry structure.

Let,

γ=density of water

Sm=specific gravity of masonry material

SL=specific gravity of material giving lateral force (e.g. water, soil etc)

h=height of the structure

x=width of the structure

W=weight of structure=h*x*s* γ

μ= coefficient of friction

Case1: For overturning

Moment dut to lateral force=moment due to weight of the material

½* γ*sL*h2*h/3 =W*x/2

Or, ½* γ*h2*h/3*sL = γ *sm*h*x*x/2

Or, (x/h)2=(sL/(3*sm))

Or, x/h=sqrt(sL/sm/3)

For water sL=1;for stone masonry sm=22/9.81=2.14

Therefore, x/h=0.394≈0.4

Case2: For Sliding

Horizontal force=friction factor*weight of the structure

½* γ*sL*h2= μ (γ*sm*h*x)

Or, x/h=sL/(2*sm* μ)

For water and stone masonry and using μ=0.65

x/h=0.359≈0.4

Thus from above derivation we see that the minimum base width/height ratio of the rectangular block to resist the lateral (triangular here) force with safety factor 1 is 0.4.

With safety factor of 1.5 the minimum width/height ratio becomes 1.5*0.4=0.6.