The original textbook remains in print (now in its third edition, with co-authors), and the demand for worked solutions persists. Legitimate platforms like Chegg, Course Hero, and even YouTube offer problem walkthroughs, but they operate in a legal gray area when reproducing exact problems.
If you can't proceed, use the manual only to get past the specific hurdle (e.g., a tricky integral or a boundary condition), then try to finish the problem independently. Advanced Mechanics Of Solids Srinath Solution Manual