# Bridge to Sicily - what are the (span) limits? **URL:** \ **Category:** Factual Questions\ **Tags:** science-math\ **Created:** [August 6, 2025, 6:12pm UTC](https://boards.straightdope.com/t/bridge-to-sicily-what-are-the-span-limits/1021782 "2025-08-06T18:12:33Z")\ **Posts on this page:** 1\ **Showing post:** 28
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [August 7, 2025, 4:10am UTC](https://boards.straightdope.com/t/bridge-to-sicily-what-are-the-span-limits/1021782/28 "2025-08-07T04:10:12Z")
> [@Stranger\_On\_A\_Train](#): > > Someone here once proposed a rail launcher that would have some big truss structure that would go up to 30 kilometers (going from memory; I can’t find the thread) That was me, by the way: > [@Quickest time a Single-Stage-To-Orbit futuristic fighter-jet take could get into orbit?](https://boards.straightdope.com/t/quickest-time-a-single-stage-to-orbit-futuristic-fighter-jet-take-could-get-into-orbit/783548/49): > > What I called ridiculous was not your overall objections, but your specific claim that the tower would have to be hundreds of kilometers wide at the base. I’ve no idea what you have in mind as a design, but whatever it is, you’ve done something wrong if it has to be that wide. Regarding the footings, a 1-m slice of the tower would weigh in the ballpark of 10^6 kg. Which means the average ground pressure is a measly 1 kPa. If we limit ourselves to ground loadings of 100 MPa, it means we’re o… That one was even more speculative than the discussion here. --- _[View the full topic](https://boards.straightdope.com/t/bridge-to-sicily-what-are-the-span-limits/1021782)._