Bluebeam Tip: Reduce file size and make it faster

As a structural engineers, we are always working on existing buildings. Most of the time we scan the as-built files or obtain those from owners. Most of the times, the scanned pdf files are really difficult to work because those are big and slow.

Here is Bluebeam tip to reduce file size and make it faster:

Under Document Tab, Go to button “ Process” and from the drop down menu select “Reduce File Size”

Following menu will pop up. Compress the file as much you want. The text at the bottom will tell you the Estimated size of the file and reduction in size.

For Scanned files, I usually go to full compression and the quality of drawing is not reduced. But you can try different settings for your project.

Note the file size below: from 477 MB to 43.3 MB file. Also the pdf is very fast to use now.

ETABS – Deleting Reference Planes

  1. Click the Edit menu > Edit Stories and Grid Systems command to access the Edit Story and Grid System Data form.

  1. Highlight a Grid System definition in the Grid Systems display area.

  1. Click the Modify/Show Grid System button to display the Grid System Data form.

  1. Click the Reference Planes button in the Click to Modify/Show area of the form.


Before running P-Delta analysis, always check the model for simple modal analysis and gravity loads to make sure that analysis model has no stability issues or other warnings/errors.
I have tried two methods for running P-Delta, both are explained below, hope this will be helpful.

Method 1: Initial P-Delta

1. Define load case for e.g “P-Delta” with

2. Include all dead load cases in that P-Delta case

3. For all load cases click on ” the Stiffness at end of nonlinear case” to activate it and select “P-Delta” load case in the drop down menu.

4. Run the analysis, SAP will include the P-delta effects.

Method 2: Non-Linear Load combos

1. Convert all the load combos into Non-Linear P-Delta case



2. For all other load cases keep the zero initial condition

3. Run the analysis, it will include the P-delta effects.

Calculator For Engineers

I was searching for a website which can do small quick calculations for example calculate moment of inertia, section modulus, plastic section modulus etc. and found following website. Hope this will be very helpful.

Screenshot 2014-08-26 17.04.58


Zero Compression Element

When we want to model tension cable rods or any member with zero compression  and want to use finite element model for this purpose then follow the procedure below. This procedure is written considering CSI products (SAP or ETABS) but the concept should be similar for most of the softwares.


  1. Select the frame elements which should not take any compression.


  1. Click Assign > Frame/Line > Tension/Compression Limits.


  1. Check the box for Compression and define a limit of zero in the text box (default=0)



In order to run the analysis for tension-only members, we have to run Non-Liner Static analysis which is very simple.

  1. Go to Define > Load Cases and select the case you want to change to non-linear static (usually lateral load cases).
  2. Select Non-Linear Static from the pull down menu.


  1. Input other load cases in the box with appropriate load factors.
  2. Run the analysis and check the members with no compression and confirm that members are only taking tension.
  3. Perform the design.


Alternate option for defining non-linear load cases:

  1. Click Define > Load Combination
  2. Select Load combinations needs to convert to Non Linear combos



  1. Click button ” Convert Combos to Nonlinear Cases
  2. Run Analysis and check the forces in the members.
  3. Perform the design.