Vertical Transportation for Building Structure

In the design of a multi-storey building, much thought should be given to the type of vertical transportation, number of units needed and their location, arrangement and design. Vertical circulation of traffic may pass from level in a high rise building by elevators, escalators, dumbwaiters, Stairs, Ramps and Conveyors. Stairs for use when power is shut off, or when there is mechanical failure always supplements the powered equipment unit, or maintenance work is in process or in emergencies.

RAMPS

Ramps are sloping surface that can be used to provide an easy connection from floor to floor especially when large numbers of people or vehicles are moving from time to time. Ramps are adopted for buildings, such as stadiums, railroad stations, exhibition halls, garage buildings, etc. it is generally built with slopes up to 15% (15 feet in 100 feet) but 10% is preferred. With 10% slope and a storey height of 12 feet a ramp connecting two floors would have to be 120 feet long. It can be curved, zigzagged, u-shaped or spiraled and bin all cases should be constructed with a non-slip surface.

STAIRS

A stair is a series of flight of steps connected by landings, for passing from one level to another. They may be constructed of wood, concrete or steel.

The minimum width of stair shall be .90 (900mm) for occupant load of 50 or less and shall not be less than 1.10 (1100mm) for more than 50 occupants load. The rise of every step in a stairway shall not be less than .25 (250mm).

A series of steps without an intervening platform or landing is called a flight.

ELEVATORS

Elevator is equipment for transporting people or things up and down the building. Whether a multi-storey building is used as offices, hotels, hospitals, schools or commercial centers, dependable time saving vertical transportation by elevators has become a prime necessity.

Elevator is a platform or car for hoisting or lowering passengers or freight, attached by cable to a machine that moves it in a shaft through guide rails in vertical direction serving two or more floors of a building.

                Two Types of Elevators in general use;

1.       Electric elevator

2.       Hydraulic Elevator

ELECTRIC ELEVATORS

                Electric Elevators are used exclusively in tall building and operated by direct current (dc) motors.

                Two Types of Elevator Traction Machine;

1.       Gearless Traction Machine

2.       Geared Traction Machine   

Traction Machine is one in which the motion of the car is obtained by means of fiction between

the traction sheave and the hoisting cable.