Value Engineering of Reinforcement Used in Large Diameter Drilled Shafts

Deep and large diameter drilled shafts use mostly bundles of Grade 60 (415 MPa) reinforcing bars as longitudinal reinforcement with rebar splices to make it longer. Lower grade steel requires large number of bars which result in rebar congestion and difficulty in placing concrete. This leads to increased labor cost for fabrication and installation. By utilizing larger size and higher strength threadbar, the congestion of rebar can be reduced significantly and bundling of bars can be avoided. The lap splices are replaced with simple threaded couplers and end hooks are replaced with end terminators. Threadbar conforms to ASTM A615-15 and can be epoxy coated if required for corrosion protection. This paper describes an attractive value engineering of replacing Grade 60 (415 MPa) bundle of rebars with larger diameter Grade 75 (515 MPa), Grade 80 (550 MPa), and Grade 100 (690 MPa) threaded bars and threaded couplers in some specific drilled shaft projects in the United States.