ramp up vs build up

ramp up and build up both are verbs.

Word	Noun	Adjective	Verb	Adverb
ramp up	No	No	Yes	No
build up	No	No	Yes	No

As verbs, ramp up and build up are synonyms defined as:

Other synonyms of ramp up include build, work up.

ramp up (verb)	build up (verb)
bolster or strengthen	form or accumulate steadily
	enlarge, develop, or increase by degrees or in stages
	change the use of and make available or usable
	bolster or strengthen
	prepare oneself for a military confrontation