how to perform spike testing with gatling

I was looking for a way to ramp up from 1 to 30 requests per second for a duration of 3 hours. Could the code below be the right way to do this?

rampUsersPerSec(1) to (30) during(3 hours)

Also, could anyone point me to how I could simulate a spike test. using the injection? Could the example below be an example of a spike test:

setUp(scenarioBuilder.inject(constantUsersPerSec(100) during(30 minutes)).throttle(
reachRps(100) in (10 seconds),
holdFor(2 minutes),
holdFor(3 hours)