Experimental and numerical analysis on flexural behavior of improved U-bar joint details for accelerated bridge construction

•An improved U-bar loop connection that eliminates welding operations was proposed.•A novel double-loop connection with notched configurations was developed.•Both proposed connections demonstrated ductile behavior and splendid bearing capacity.•Numerical studies were carried out on the novel double-loop connection with ABAQUS.•Design method for double-loop connection was put forward through parameter analysis.