Messing up the heat treatment isn't a design failure, it's a construction failure. The design specifies acceptable parameters for the rebar. If the rebar is wit

Messing up the heat treatment isn't a design failure, it's a construction failure. The design specifies acceptable parameters for the rebar. If the rebar is within those parameters but the bridge fails because the parameters were wrong, the designer is responsible. If the rebar was out of the specified parameters, the contractor is responsible. If I'm reading the article right, "design" would encompass interaction boundaries as well as things like CPU/memory requirements, information storage, and security.