2 x 10 floor joists spaced 16" o.c., spanned 17’-9". My understanding is the maximum span for this joist is 16’-5" or 15’-5" depending on what standard you follow. There was a double 2 x 4 girder framed on the flat, supported by a couple of columns at the approximate center to help support the beams, although it did not run the full length of the basement. Settlement noted in floor where “girder” was missing.
My belief is the span is too long where it is not supported at any other point, and the 2 x 4 on the flat are basically useless. Obvious crack prevalent, and cracks in the drywall where the 2 x 4 were covered.
I am recommending further evaluation by a licensed engineer but like to hear your thoughts.