Weight, Load
&Force.
Table Of Contents
01 02 03
Weight Loads Forces
01. Weight:
To find weight of an object you need to find it’s
volume and density consiering that the
mathimatical formula used to find the weight
is multipling the volume of an object by its
relative density
If you expose the weight of an object to earth
gravity that will result in creating Loads
02. Loads:
A load is weight of an object affected
by gravitational force
Types of Loads:
A B C
Dynamic
Dead Loads Live Loads
Loads
A) Dead Load:
• They are always present in buildings
• They don’t vary with time
• Includes weights of materials and components that
effect the structure
• Dead loads can be estimated with greater certainty than
other load types as both their dimensions and densities
are known with greater accuracy
• The dead load includes the self load of the component
plus the dead load of the elements that it supports
B) Live Loads :
• It is defined as the load whose magnitude and
placement change with time such as loads of People,
Animals, Furniture and any movable equipment
• Live Loads are divided into 2 more categories:
1) Roof Live Load
2) Floor Live Load
1. Roof Live Load:
• Live load on a roof takes into account the
weight of a repair personnel and temporary
storage of construction or repair materials
and equipment
• The roof live load is the floor live load for
the anticipated future occupancy
2.Floor Live Load
• It depends on the occupancy and use of buildings.
• It may also be called occupancy load.
• Floor live loads are determined by combining the
loads of people, furniture and any movable
equipment that may result from particular
occupancy.
• Worst expected situations should be considered for
safety measures and to make sure that the structure
is designed to bear maximum possible live load that
may be placed on it.
C) Dynamic Loads
01 02
Rain Load Wind load
03 04
Earthquake load Other loads
1) Rain loads:
• Even though roofs are designed to have
proper drainage so that no accumulation of
water occurs loads resulting from accidental
accumulation of melted snow or rain water
must be considered a possibility if the drains
gets blocked by and chance
• Flat roofs are particularly vulnerable to rain
water that on the long run may cause
buildings to collapse
2) Wind loads:
• Wind Load increase with the height of
a building
• To design tall buildings it must be
heavily dominated by wind bracing
requirements
• Wind speed is fundamental to
determining wind loads on buildings
as wind load is directly proportional to
square the wind speed
• Even if the wind blows from only a few
directions I most locations it is safe to
assume that the wind my come from
any direction
3)Earthquake loads:
• Earthquakes occur in many regions of the world
particularly in regions near an active geological
fault as the San Andreas fault that runs along the
western coast of California large ground motion
frequently occur that can damage buildings and
bridges
• The ground motion created by major earthquake
force causes the buildings to sway back and forth
• Assuming that the building is fixed at its base the
displacement of floors will vary from zero at the
base to maximum at the roof
4)Other dynamic
loads:
• Other dynamic effects should be
taken into consideration like
moving vehicles and elevators
• As a result of the movement of loads
or load transfer forces are exerted
03. Forces
Force is the result from movement od a load
Or
It is an action opposing a change occuring to a body
Types of Forces :
01 02 03
Compression Tension Torsion
04 05
Shear Bending
• Compression Force: Physical force pressing inward on an object
causing it to shrink or become compacted
• Tension Force: A longitudinal force acting on a body causing it to
stretch
• Torsion Force: A force acting on a body causing it to twist
• Shear Force: A force that presses different parts in a body in opposite
direction at the same time
• Bending Force: A force that occurs when a body is fixed from 2 sides
and a force acts on its middle part causing compression force on the
top part and tension force on the bottom part
Examples on forces acting on
buildings :
Compression Force
Torsion Force
References:
- Fundamental of structural analysis.
- Building Construction; Principles,
Materials, and Systems.
