By definition wouldn't all bridges "barely work"? Yes it's spec'd to handle X load, now putting X+1 might cause some damage because it was never tested or designed for X+1.
Which doesn't mean that we have no reusable or generalizable quality metrics - we do. But they tend to express things that correlate to an abstract of quality, and not a failure threshold.
The most honest systems in software are the ones that do not scale, because they have built in their hard failure point - and from that, tolerance metrics similar to bridges can be predicted and planned for. It's software that has to do everything in a multitude of configurations at great speed that runs into deep architectural issues, because it hypothesizes a bridge that will someday tolerate an infinite load.