The supports for the thing are what will kill you.
At 1km from the tangent point, you're only 8cm above sea level. At 10km, you're 8m above. So far, so good. At 100km, you're 784m up. At 1000km, that support is 78km tall.
The only economical way to do even part of it would be to build an evacuated acceleration track up the side of an existing mountain. The west face of Chimborazo in Ecuador is probably the ideal location for something like that. But you would need to accelerate at 23g for about 283km (51s) in order to reach escape velocity without any additional boost after the launch vehicle exits the track. That would be strictly for unmanned missions.
Accelerating at 3g for 283km (139s) to a height of 6268m above equatorial sea level would achieve 4080m/s, of an escape velocity of 11170m/s. You get 465 m/s for free by being near the equator. That leaves a delta-v of 6625 m/s. If your launch vehicle used RS-25 rocket engines, that means an extra 13% of your total launch vehicle mass can be cargo instead of propellant. The acceleration track would effectively substitute for the first stage of a rocket.
In order to reach escape velocity externally at 80 km above the equator (7850 m/s), you need 250 seconds at 3g (29.42 m*s^-2) of acceleration, which takes 1850 km. This is why the launch loop uses tethers instead of towers, and supports itself mainly with tension rather than compression.