crosspiece vs tie beam

crosspiece

noun
  • A horizontal or transverse beam or similar member that extends across or perpendicular to something. 

  • A bar or timber connecting two knightheads or two bitts; a timber over the windlass, with pins for belaying the running rigging. 

tie beam

noun
  • a horizontal beam that serves to prevent two other structural members from separating while forming the base of a triangular truss for a pitched roof. 

How often have the words crosspiece and tie beam occurred in a corpus of books? (source: Google Ngram Viewer )