What always happens when you are designing a really big rocket? Yes, all looks well and good, then you go to launch it and BOOM, it collides with the LaunchPad and explodes. Not anymore!
You just need to extract the part and plugin into KSP folder, no need to add the part to the craft or anything.
Bonus: Move the Obliterator part to the VAB/SPH construction area, and it will obliterate the VAB/SPH interior and scroll limits, build as large as you want!
Download here: Launchpad Runway
Source code available here, GPL license