Actually, a lot of applications of steel in construction could and should be partially replaced with bamboo. Ideal and cery promising is the combining of bamboo frames with other materials for regular buildings.

On bamboo-steel composite:

https://jwoodscience.springeropen.com/articles/10.1186/s10086-019-1830-4

https://jwoodscience.springeropen.com/articles/10.1186/s10086-019-1830-4

Bamboos 3 times cheaper,, AND its got a very small climate impact. The environmental impact of buildings could be greatly reduced by using this alternative frame construction method, combined with green modifications to wall construction, etc.

EDIT; there are also ways to produce steel at a fraction of the environmental impact of conventional production methods, but it costs more. This can be offset by combining steel with the cheap bamboo into a composite frame.