The midas model is for a multi-channel prestressed girders bridge 30 ft span and 24.75 ft width. The bridge is composed of 9-channel prestressed girders placed side by side. The bridge was modeled with frame elements for the girder's webs and plate elements for the girder's flange. Bridge dimensions and midas models are shown below.
Figure 1: Bridge Details
Figure 2: Midas Model
Strands material is ASTM A416-250 low relaxation, and tendon properties are as follows:
The figure below shows midas defined strands material and property.
Figure 3: Strands defined material and property
Before creating tendons profile, renumbering girders webs frame element is necessary to allow for using the MCT easier. To do so, the frame elements were numbered as follows:
Figure 4: Renumbering girder 6 web 2 frame elements
Figure 5: Renumbered girders webs frame elements
Next step, we will define one tendon profile then we will copy that to all girders with the MCT tool.
Figure 6: Defining girder 1 web 1 first strand (CH1-W11)
Now we can use the MCT tool to copy tendon profile CH1-W11 to the other 3 remaining tendons in girder 1 web 1 (CH1-W12, CH1-W13, and CH1-W14).
Figure 7: MCT Definition of tendon CH1-W11
Figure 8: Copying tendon CH1-W11 to the remaining tendons in Girder 1 Web 1
Figure 9: Girder 1 Web 1 remaining tendons defined with the MCT tool
Figure 10: Girder 1 Web 2 tendons defined with the MCT tool
Figure 11: Defining prestressing force for tendon CH1-W11
Figure 12: Defining tendons prestressing force with MCT tool
Co-Author: Sarah ElSawah, MS, PE, Structural / Bridge Engineer at SDR Engineering Consultants