297RAM Concept

Chapter 45

45 Strip Wizard Tutorial

This chapter walks you through the steps for using Strip Wizard to provide a preliminary design for the slab (grid B) in the PT Flat Plate Tutorial.

Alternative metric values and units are identified in square brackets [] next to the US units. The metric values are not exact conversions.

The codes used are ACI 318-02, AS3600-2001, and BS8110:1997.

For more information, see Using Strip Wizard on page 161.

45.1 Start Strip Wizard

When you choose File > Strip Wizard, the New File dialog automatically opens before the Strip Wizard dialog box is opened. After you create the new RAM Concept file, the Strip Wizard dialog appears.

Start the Strip Wizard:

1 Choose File > Strip Wizard.2 In the New File dialog box, set the Structure Type to Elevated and choose the Code.3 Click OK.

4 The Strip Wizard dialog box appears; click Next to proceed to the General Parameters page.

45.2 Set the general parameters

On the General Parameters page, you define the structure type, number and type of spans, and concrete mixes.

Set the general parameters as follows:

1 Choose Two-Way as the structural system.2 Check Post-tensioned.

3 Set the number of spans to 3.

4 Check Asymmetric strip.

5 Set the concrete mix for slabs and beams to 5000 psi [32 MPa for AS3600; C32/40 for BS8110].

6 Set the concrete mix for supports to 5000 psi [32 MPa for AS3600; C32/40 for BS8110].7 Click Next to proceed to the Span Data page.

45.3 Enter the span data

Enter the span dimensions and data on the Span Data page. (The type of data entered depends on which structural system you chose on the General Parameters page.)

Set the span data as follows:

1 Set the length of Span 1 and 2 to 30 ft [9 m].2 Set the length of Span 3 to 25 ft [7.75 m].3 Set the thickness of all three spans to 10 inches [250 mm].

Note: To set all the values in a column at once, enter the value in the Typical row (first row) of that column. For example, for the step above, you can simply type 10 [250] in the Typical row of the Thickness column to set the thickness of all three spans to 10 inches [250 mm].

4 Set the left start width of Span 1 to 11.5 ft [3.5 m].5 Set the left start width of Span 2 and 3 to 15 ft [4.5 m].6 Set the right start width of Span 1 and 2 to 14 ft [4.25 m].7 Set the right start width of Span 3 to 1 ft [0.3 m].8 Set the left end width of Spans 1, 2 and 3 to 15 ft [4.5 m].

9 Set the right end width of Span 1 and 2 to 14 ft [4.25 m].10Set the right end width of Span 3 to 1 ft [0.3 m].

Figure 45-1 The Span Data page.

11Click Next to proceed to the Support Data page.

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45.4 Create the supports below

Add the four supports in the Supports Below table on the Support Data page.

Set the supports below as follows:

1 Set the depth of all four supports below to 24 inches [600 mm].2 Set the width of all four supports below to 24 inches [600 mm].3 Set the height of all four supports below to 10 ft [3 m].4 Leave the bottom and top fixity of all supports below as Fixed.

5 Click Next to proceed to the Drop Caps and Drop Panels page.

45.5 Add drop caps

Enter the dimensions for a drop cap at Supports 2 and 4 in the Drop Caps table (top table) on the Drop Cap and Drop Panels page.

Set the drop cap data as follows:

1 For Support 2 in the Drop Caps table set the following values:

Set the thickness to 20 inches [500 mm].

Set the left width to 22.5 inches [600 mm].

Set the right width to 22.5 inches [600 mm].

Set the before length to 22.5 inches [600 mm].

Set the after length to 22.5 inches [600 mm].

2 For Support 4 in the Drop Caps table set the following values:

Set the thickness to 20 inches [500 mm].

Set the left width to 33 inches [900 mm].

Set the right width to 12 inches [300 mm].

Set the before length to 33 inches [900 mm].

Set the after length to 0 inches [0 mm].

3 Click Next to proceed to the Loads page.

45.6 Specify the loads

Enter the area loads on the Loads page.

Set the loads as follows:

1 Set the typical Dead Area Load to 20 psf [1 kN/m2].2 Set the typical Live Area Load to 40 psf [2 kN/m2].3 Click Next to proceed to the Post-Tensioning page.

Note: You can leave the Dead Line Load and Live Line Load fields blank (no need to enter zero).

45.7 Define the post-tensioning

Enter the post-tensioning parameters on the Post-Tensioning page.

Set the post-tensioning as follows:

1 Uncheck the stressing Start and End check boxes.

2 Set the minimum P/A to 140 psi [1 MPa].3 Set the minimum balance load percentage to 65%.4 Click Next to proceed to the Reinforcement page.

45.8 Specify the reinforcement parameters

Enter the reinforcement parameters on the Reinforcement page.

Set the reinforcement as follows:

1 Set the top reinforcing bar to #5 [N16 for AS3600; T16 for BS8110].2 Set the bottom reinforcing bar to #4 [N12 for AS3600; T12 for BS8110].3 Set the top and bottom reinforcement clear cover to 1 inch [25 mm].

Note: Strip Wizard does not differentiate between cover to tendons and reinforcement bar.

4 Check the Perform punching shear checks box.5 Set Cover to CGS to 1.625 inch [41 mm].6 Click Next to proceed to the Completion page.

45.9 Complete the Strip Wizard

Completing the Strip Wizard is the final page of the Strip Wizard dialog box. You can save the data you just entered in a Strip Wizard Settings file by clicking Save. When you click Finish, Strip Wizard creates your strip in the open RAM Concept file.

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Complete the strip:

1 Click Save and name the file in the Save Strip Wizard File As dialog box that appears.2 Click Finish.

45.10 Proceed with RAM Concept

After you have completed Strip Wizard, you can proceed with RAM Concept. After you have created your strip, generate the mesh (with a 2.5-foot [0.75 m] mesh) and run a calculation analysis. Refer to the relevant manual chapters, or one of the three PT Flat Plate tutorials for further information.

View your strip:

1 Choose Layers > Mesh Input > Standard Plan.

Figure 45-2 The completed strip on the Mesh Input: Standard Plan.

Figure 45-3 The Element: Standard Plan showing the completed strip af-ter the mesh has been generated.

Figure 45-4 The Element: Standard Plan after calculation and mesh re-generation.

Figure 45-5 The completed strip on the Latitude Tendon: Standard Plan.

45.11 Comparison with PT Flat Plate Tutorial

The results of the Strip Wizard analysis are similar but not the same as the PT Flat Plate Tutorial. The reasons for different results include:

Strip Wizard does not automatically consider transverse continuity effects.

Increased balcony loads not considered by Strip Wizard.

Strip Wizard automatically modified the drapes in spans 2 and 3 (you can change these if you wish).

Longitude tendons not considered by Strip Wizard.

45.12 Conclusion

Strip Wizard allows you to perform a preliminary or final design for a strip within a floor. The results are similar to those generated by any strip program, but not as accurate as a RAM Concept model that considers all of the irregularities within a floor.

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