The landlord is very courageous, claiming to be a 9-meter-long girder, and dare to find it on the Internet to piece together the housing structure! Look at the so-called "structure map" you provided, it's a complete trip for foreigners! I don't even have the basic knowledge of drawing, and I can't even draw a building plan. Painters didn't learn GB5000 1-20 10 Unified Standard for Architectural Drawing at all. Don't know the rules of architectural drawings and dare to mix outside, which makes people sweat! The 9-meter-long girder is not only a problem of reinforcement, but also a problem of how to construct the bearing.
I want to nudge, but I can't see the size. A closer look scared me to death. We must start with enlightenment. Forget it, I have to persuade the landlord to care about life. Don't play games with life, property and public safety. We should entrust a qualified design unit.