The ultimate moment defined in the road bridge specifications until 2002 has been changed to the bending moment equal to the limited state at seismic performance 2 or 3 (Mls2 or Mls3) in the revised specifications in 2012. Not only the name but also the definition has been renewed in the specifications. So far, the ultimate moment was determined by only the ultimate strain of concrete, but it is decided by either concrete or reinforcing bar now. In this topic, we will explain how to check which of concrete or reinforcing bar the ultimate moment is determined by, which cannot be checked in the M-φ feature screen.

At first, double-click on the row "Ultimate Strength Method - Flexure" in the table displayed by clicking "Design Model | Section Code Configurations" in the Navigation (Fig.1).

Next, press the "One Shot Result" button in the "Code Configuration Propertys" screen (Fig.2).

In the "Section One Shot Result" screen, specify the same as the yellow parts in the Fig.3. Particularly, "My/Mz Input Angle" shown as the part A makes the vertically cut 2D M-N interaction figure display the 3D M-N interaction figure.

Next, enter the axial force and bending moment. For example, in the yellow parts in the Fig.4, you can see that the ultimate moment is determined by the acceptable strain of reinforcing bar when the axial force is 20000kN, judging from the material color (and the red star in the drawing). In addition, the ultimate moment is calculated in the direction of zp axis by inputting 0 in Myp and 90000 in Mzp. In fact, 1, 10, 100 or any other values can be input in Mzp since all that is required is to decide the direction.

Also, in the M-N interaction figure, you can see the determination of the ultimate moment from the color of concrete material as the compression axial force getting bigger.

Please refer to the Engineer's Studio Help for more details of the One Shot Results.