In accordance with the road designed, you need to define different transverse slopes for the bridge cross-section.
Start by defining the cross-section in the area of the spiral clothoid (station point 6). Enter a transverse slope of 5 % for this
cross-section. You will then use it for the transition between the arc and the clothoid at pier 2 (station point 3).
Next, you will modify the cross-section by adjusting it to the transverse slope of 0 %.
For the transition between the clothoid and the arc at the north abutment (station point 9), you will use the option of matching dimensions you have already entered.
To define the bridge cross-section
1 Select station point 6 and click Define New Cross-Section on the Cross-Section toolbar or Edit menu.
2 Click Add Predefined Cross-Section Variant on the Cross-Section toolbar or Edit menu and select Box girder, type 1.
Geodesy Appendix 123 As the cross-section is symmetrical, all you need to do is enter the values for the left-hand side and the slopes as shown below.
Then you will apply these values to the cross-section's right-hand side.
3 Click the top left measurement of the cantilever, enter values in the unit of length set and use the TAB key to switch to the next data entry box.
4 Click the measurement of the box girder's left side, enter values in the unit of length set and use the TAB key to switch to the next data entry box.
5 Click the icon on the left, keep the mouse button pressed down and drag the cursor to the icon on the right. Now you can release the mouse button again.
6 Click OK to define the cross-section.
Tip: As an alternative to TAB and Shift-TAB, you can also use the ‘Page Up’ and ‘Page Down’ keys to toggle between the data entry boxes.
After having defined the bridge cross-section, you will now define the caps as separate cross-sections.
To create caps as additional cross-sections
1 Select cross-section point 11 in the tree structure and click Addition to Cross-Section on the Cross-Section toolbar or Edit menu.
2 Click Add Polygon on the Cross-Section toolbar or Edit menu.
3 The coordinates of cross-section point 11 are used for the first point. Click OK to confirm the values.
4 Click in the graphics area above cross-section point 11.
The coordinates of the point clicked are displayed.
Geodesy Appendix 125 5 Select the Delta option and enter the following values: X = 0.00,
Y = 0.15
6 Define the other four corners one after the other. To do this, click roughly where you want to place each corner and adjust the delta values in the dialog box:
Point 3 X = -3.25 Y = 0.13 Point 4 X = 0.00 Y = -0.50 Point 5 X = 0.35 Y = 0.03 Point 6 X = 0.00 Y = 0.2625
Note: Point 6 is equivalent to point 1 of the bridge cross-section.
7 Right-click in the graphics area to finish entering the cross-section.
8 Use the same approach to create the cap on the right. The reference point is point 9 of the bridge cross-section.
9 Click Save and Exit to assign the cross-section to the entire route.
As you cannot use the entry dialog box to modify cross-sections calculated by Allplan, you will leave the cross-section as it is and use it for the transition between the arc and the clothoid at pier 2.
Then you will modify the transverse slope of the cross-section in the area of the spiral clothoid.
To modify cross-sections
1 Select station point 3 and click Lock Current Cross-Section on the Cross-Section toolbar or Edit menu.
2 Select station point 6 again and click Define Reference Point on the Station toolbar or Edit menu.
As the first point of the bridge cross-section is at top left, place the reference point there.
Geodesy Appendix 127 3 Select the first option. Point 1 serves as the reference point. Leave
this setting unchanged.
4 Click OK to define the reference point.
5 Click Edit Cross-Section on the Cross-Section toolbar or Edit menu.
The cross-section definition is displayed.
6 Click Modify Cross-Section on the Cross-Section toolbar or Edit menu.
The entry dialog box of the defined bridge cross-section is displayed.
7 Change the transverse slopes of the road to 0 % and click OK to confirm.
As a result, the position of the cap on the right is too high and needs to be reduced by a value of 8.50 * 5 % = 0.425.
8 Select cross-section point 6 of cross-section 3 and click Modify Point on the Cross-Section toolbar or Edit menu.
9 Change the value of the Y coordinate to -0.0725.
10 Use the same approach to change the Y coordinates of the other points to the following values:
Point 1 Y = 0.00 Point 2 Y = -0.2625 Point 3 Y = -0.2925 Point 4 Y = 0.2075 Point 5 Y = 0.0775
Note: Make sure that you modify the points in the correct sequence. If these modifications produce interlaced areas, the number of points will change.
11 Click Save and Exit to assign the modified cross-section.
Tip: If these modifications lead to additional points or missing points, thus changing the shape of the area, stop modifying the cross-section without saving and start again at step 5.
Geodesy Appendix 129 For defining the bridge cross-section at the transition between the clothoid and the arc at the north abutment, you will use the option of matching dimensions you have already entered.
To retrieve the bridge cross-section from the database
1 Select station point 9 and click Define New Cross-Section on the Cross-Section toolbar or Edit menu.
2 Click Add Predefined Cross-Section Variant on the Cross-Section toolbar or Edit menu and click OK to confirm the Selection of Cross-Section Variants dialog box.
3 Click Record Management at bottom left, choose Last entry and click OK to confirm.
4 Change the transverse slopes of the road to 5 % and click OK to confirm.
5 Create the two caps as additional cross-sections as described in
"Task 2: entering cross-sections". Then click Save and Exit.