- Both precast girder and splice girder bridges need to be considered and analyzed for the before-composite and after-composite state depending on the construction stages.
- For precast girder, the most common construction sequence is that the pre-fabricated girders are installed as per span. And then cast the deck slab and make continuous.
- But splice girder construction sequence is including use of temporary shoring, segment girder sequence and post tensioning.
- A simplified of typical construction sequence for both precast girder type and splice girder type are automatically presented in construction stage tab.
Please note that not more than 10 construction stages can be created in a conventional version of midas Civil. In order to create more than 10 construction stages, the license type must be "Advanced".
From main menu, select [Structure] tab > [Wizard] group > [Prestressed Composite Bridge]
Prestressed Composite Bridge Wizard Construction Stage dialog box
Check to activate and define the construction stages. When deselected, it is generated as a completed model.
Girder Splice (Splice Girder Type only)
Check to activate the girder segment in a different construction sequences. If checked off, Girder segment is constructed for the entire bridge at the same time.
Girder Splice Construction...
First, select Girder Stage and input Duration that needs to be add or modify the different Girder Segment stage.
Second, select the girder segment list that needs to specify each different stage and move to the Selected Girder Segment List and Click “Add”.
Third, repeat the second step until the Adding or modification is completed. Finally, click [OK] to close.
After finishing the Girder Splice construction, Detailed Girder activating stage are included in Girder activated stages. (in example, CS1-1, CS1-2, CS1-n or CS2-1, CS2-2, Cs2-n (including substructure stage)
Stage in which selected girder segment are activated in. This girder segment stage is ordered with a sub stage in girder activated stage. Also, the stage number must start from 1 and increase by 1 only.
Duration : Duration of the construction stage in days.
Girder Segment List : Girder segments that are available to be activated in the selected stage.
Selected Girder Segment List : Girder segments to be activated in the selected stage.
Temporary Support Position…
Based on the splice location specified in the Girder Information in the Section tab, the temporary supports conditions can be specified during the construction sequences.
Splice Support Condition : All of Splice position that is specified in the girder information in Section Tab are showed in this dialog box
At the splice position(s) selected in this box is supposed to have a temporary support conditions. Temporary DX, DZ support is activated at the end segment of splice position in each girder segment activation stage. Regarding modeling, the My is released at the i- and j- end of the element located at the end of each girder segment.
Post-tensioning Tendons (Splice Girder Type only)
Pre-tensioning tendons are not applicable in defining the post tensioning tendons. Tendon that is defined each splice segment is considered as pre tensioning tendon, it is automatically considered as the girder segment is activated in construction stages.
Tendons defined along the entire bridge length is considered as the post tensioning tendons. Only this type of tendon is shown in the "Tendon List".
Post-tensioning tendon may be applied either before and/or after the deck placement.
In the wizard, terminology for "1st Tendon"and "2nd Tendon" is defined as follows.
1st Tendon : Post tensioning tendon which is conducted prior to the deck placement
2nd Tendon : Post tensioning tendon which is conducted after the deck placement
It is not necessary to assign both "1st and 2nd Tendon".
In construction stage, the tendons defined as the 1st and 2nd Tendon are automatically activated.
Define Post Tendons...
Tendon List : Tendons that is specified in “all span” type tendon in tendon Assignment in Tendon Tab are showed in this dialog box.
1st Tendons : If tendons are stressed before deck is cast, move the tendon to 1st tendon dialog box.
2nd Tendons : If tendons are stressed after deck is cast, move the tendon to 2nd tendon dialog box.
Check to define the longitudinal and shear reinforcements for the deck. If the reinforcement is defined, the reinforcements are considered for calculating the section stiffness.
Section Manager : Refer to [Properties] tab > [Section] group > [Section Manager] > Stiffness