## KNOWLEDGE

水平器の知識

## What is a gradient?

A gradient means the degree of inclination. It usually means ratio of distance from a horizontal plane to change of horizontal way of inclination.

## What is the gradient for civil engineering work?

It is the gradient of embankment or retaining wall and indicated in a ratio of horizontal distance to vertical distance. For example, 15% at the embankment gradient means the horizontal distance toward the vertical distance of 1 is 1.5. 3.5% means toward the vertical distance of 1, the horizontal distance is 0.35.

## What is the gradient for construction work?

An inclination degree of a roof is indicated by pitch. It has been indicated by “shaku”, which is Japanese architectural measurement indication method, since ancient times. A roof pitch is expressed how many “sun” (=3.03 cm; 1/10 shaku) is the vertical distance to the horizontal distance of 1 shaku (=30.3 cm). As explaining a picture left, the horizontal distance is 1 shaku and the vertical distance is 4 sun; thus, it is called the pitch of 4 sun (12.12 cm).

## What is the gradient for facility work?

A water pipe is laid underground with a certain gradient toward exit. This gradient is shown by b/a. If a=1000mm, b=10mm, it is called the gradient of 1/100.