One thing I have been uncertain about is how many gees can a rocket withstand at launch. I still don't know. I'm not sure if very competent rocket engineers would know- though I'm sure they know a lot more about it than I do.

When I first was outlining what a pipelauncher was, I used 3 gees acceleration as what I thought was a reasonable number. This based my knowledge that rockets typically exceed 3 gees in going through the atmosphere, but I also later realized that when rocket had such acceleration they were considerable lighter, so though some or most parts of a rocket could easily withstand 3 gees, some parts may not. And perhaps more importantly whatever structure was involved in mounting the rocket may not be rated to withstand high gee loads with a fully fueled rocket- a empty rocket may be designed to withstand high gees it may undergo from moving it around before it gets to the pad, but fully fueled rockets aren't usually moved around.

But it can be assumed that a rocket engine needs to be mounted to something that can withstand the gee loads of the engine. So considering these things I figured that maybe 3 gee was too much to expect and that 1 gee was more reasonable- and perhaps even scaling it down the gee force of rocket acceleration at launch [somewhere around 1/2 gee].

I was recently watching a show on one of next missions to the Moon and they were testing a component which was critical to the mission. They were testing it for gee rating of 13 gees [they weren't doing this by spinning it or something but rapidly vibrating it for extended periods] and on the show the part failed. The point I drew from this is not that all parts of a rocket are rated at 13 gees or something [they may or may not be], but rather the obvious point that vibrations can cause a lot of stress and of course rocket motor operations are not something that not always very smooth- and in engine ignition at lift off it can be rough [and of course also true through out their operation].

The point is that the acceleration from a pipelauncher would not involve sudden motion or vibration- a pipelaucher would incapable of vibration or sudden motion and also incapable of swaying motions- a pipelauncher in a severe hurricane might move a little bit, but nothing like a ship or office building [note, you wouldn't want a rocket on a pipelauncher during this hurricane].
A pipelauncher may accelerate faster than any elevator but it would be smoother or less jerky than most elevators.

In summary, I don't know if it would safe to accelerate a rocket at 3 gees, but I'm starting to think that 1 or 2 gees might work on most rockets.