Hello everyone!

I appreciate any help on this. A contractor built a freestanding wall built from 16x12x6 retaining wall blocks (glued together). The city had concerns and wanted the engineer to look at it and verify. This free standing wall goes up with an outside stairs and at its tallest height is 5ft tall. What I intended to do is analyze the wind and seismic loading on it and recommend some metal straps perhaps and potentially rods drilled in a couple of places to tie the structure together and to the ground. Does that seem like a reasonable plan; can you recommend anything else?

But before I get to solutions, I have to figure out the seismic forces. Using Chapter 15 of ASCE 7, I understand I can use equation 15.4-5 if the fundamental period (T) is 0.06s or less. And that is what I need help with. Can anybody share your experience and ways to calculate T in this situation?

Thank you so much!