Originally Posted by
wiggy
Million pounds I'd suggest.
FWIW the Saturn V (first stage 5 X F-1 engines) totalling 7.5 million pounds of thrust was held down for several seconds on the launch pad prior to being released.
That was done by four relatively small, retractable hold down arms at the base of the vehicle so I'd expect the engineers these days could rig up something to hold down something with a bit less thrust...
Ah, but don't forget that there is the weight of the rocket itself holding it down; the arms only have to hold against the delta between thrust and weight.