Aluminum handle bar got broken, i know i abused it a lot, but never expected it to actually break.

In what way did you "abuse" it? Barring direct trauma, most bar failures that I'm aware of result from corrosion (eg sweat-soaked bar tape on indoor bikes) - can't imagine that this is the issue with your bike.

My question as well.

That's a pretty straight break.

Back in the days (like last year) when I would power my way up a hill standing and pulling hard on the handlebars, I was always a bit fearful that the bars would snap. Now I sit and spin.

That thing had to be at least 40 years old, it had a pretty good run. I've broken steel bars from bikes only a few years older, but I was hitting some little 1' jumps with it though.

Handlebar breakage is the thing I worry about most riding '70s and '80s bikes.

Happened to me once. A nice set of vintage GB bars gently started to give as I pulled up on them and separated completely a pedal stroke later. I was glad that there was no drama. Replaced them with a similar set of Nitto steel bars.

not a problem - one side remains and still looks good

smh

for me it’s primarily 90’s bikes

the thin walls on the lightweight bars (145 g EA70 Answer Hyperlite etc for example) don’t take kindly to misuse … and same with many of the carbon bars from that era

Oh yes indeed, they scare me too. Used carbon bars scare me even at 5 years old if the bike looks like it's been ridden much.

Aluminum I don't worry too much 'til they're at least 10 years old, but still look for abuse or trainer time.

Luckily the shape of the bars on my 2001 Lemond Buenos Aires was so godawful I had to swap those bars ASAP, and didn't have to fret over the olde bars failing.

I notice those bars are not sleeved or bulged at the stem. (No surprise, these are hardly for racing.) That increased outer diameter goes a long ways to reducing the stress at the stem edge. Aluminum handlebars fail with use, faster with hard use. That is simply a given. Better design, execution and alloys will postpone that failure but not stop it. Best approach is to simply replace aluminum parts (especially those that are cantilevers with real force applied like handlebars and cranks) before they break. (And those near pristine bars and cranks hanging up in the garage of that neatness freak who is also an animal on the bike - leave 'em hanging. Don't put 'em on your bike!)

Why abuse the bike? There is just simply NEVER a need for that. If you take care of your bicycle it will take care of you. In this case an old probably lower cost aluminum flat bar has a better potential for failing but should never be accelerated with abuse.

Pimp hand strong with this one...

it really went tubeless on the one side.

Fatigue failure over many years. Aluminum is particularly susceptible. The straight-across break indicates it failed from bending fatigue, not torsion which would cause a spiral break at 45 degrees to tubing axis. A close-up of the break faces would indicate which side the break originated, to indicate if from pulling or pushing force on bar, but those bars are also wide so also exert more bending moment at the stem clamp for a given force at the handgrips.

All structural parts on a bike should be periodically inspected, even if steel which has better fatigue life, I've had cracks on a steel frame. Lighter colored paint or bare metal is easier to detect cracks than dark colors.