Structural Strength & Stability

1. Structural Strength & Stability Loads: External Forces

2. Load – the effect of the forces acting on a structure Usually grouped into two categories: Static Load – caused by force of gravity Dead Load and Live Load Dynamic Load – caused by forces other than gravity Loads

3. The Dead Load on any structure is caused by the force of gravity acting on the structure itself. Dead Loads are those loads which are considered to be permanent; they are "dead," stationary, and unable to be removed. Example Consider a house. roofing, concrete, flooring, pipes, ducts, interior partition walls, Environmental Control Systems machinery, elevator machinery and all other construction systems within a building contribute to the calculation of the total dead load. Static Loads

4. Live Loads are not permanent and can vary (also caused by gravity). Some Live Loads are heavy, while others are light. Sometimes a structure will have no Live Load at all Example Consider a house again includes item such as furniture, pianos, safes, people, books, cars, computers, machinery, or stored materials contribute to the Live Load Static Loads

5. Dynamic Loads • A load on a structure caused by a force other than gravity • May change rapidly • Example • Consider the house again • Includes environmental effects such as loads due to the sun, earth or weather. • Wind and earthquakes loads are put into the special category due to the severity of their action upon a building and their potential to cause failure.

6. Designers attempt to anticipate loads that a structure will bear Obviously, a structure that cannot bear the weight of its own weight is a failure, but anticipating the other loads is more difficult Structural Design & Loads

7. Today’s Work • Complete this table by identifying the live, dead, and dynamic loads that apply to the given structure.