drop arch
A pointed arch which is struck from two centers that are nearer together than the width of the arch, so […]
Glossary
drop apron
A strip of metal which is fixed vertically downward at eaves and gutters of a flexiblemetal roof; acts as a
Glossary
driving resistance
The number of blows of a pile-driving hammer which are required to advance the point of a pile a specified
Glossary
driving machine
The power unit which applies the necessary energy to raise and lower an elevator or dumbwaiter car or to drive