BIS has released Draft editions of IS:1893, for comments open up to 25 June 2023. The draft codes, introduced as Part-I and Part-II :
CED 39(22343)WC: Draft Indian Standard Criteria for Earthquake Resistant Design of Structures Part 1 General Provisions [Seventh Revision of IS 1893 (Part 1)] (https://www.services.bis.gov.in/tmp/WCCED21022343_26042023_2.pdf)
CED 39(22345)WC: Draft Indian Standard Criteria for earthquake resistant design of structures Part 2 Buildings [Seventh revision of IS 1893 (Part 1)] (https://www.services.bis.gov.in/tmp/WCCED21022343_26042023_1.pdf)
CED 39(22343)WC: Draft Indian Standard Criteria for Earthquake Resistant Design of Structures Part 1 General Provisions [Seventh Revision of IS 1893 (Part 1)] (https://www.services.bis.gov.in/tmp/WCCED21022343_26042023_2.pdf)
CED 39(22345)WC: Draft Indian Standard Criteria for earthquake resistant design of structures Part 2 Buildings [Seventh revision of IS 1893 (Part 1)] (https://www.services.bis.gov.in/tmp/WCCED21022343_26042023_1.pdf)
Can be downloaded from the BIS website at the links given above (see footnote*).In view of the effort each one of the structural engineers are putting in to understanding the code, in comparison to the present edition, an excel sheet has been prepared, with which one can:
- Calculate Ah for both present and draft codes
- Calculate parameters and Response Spectrum curves which can be used to utilise the present versions of analysis packages, as it is (which as of now are already set for the 2016 version of code), for performing analysis according to the newly released draft codes; -- for the analysis packages of STAAD, ETABS and MIDAS for analysis according to the draft code. It also provides the data in a general format that can be utilized for any other package, like STRAP, for example, after suitable formatting.
- Get the detailed workout sheet for static method of seismic analysis, with all steps elaborated, and
- See a graphical comparison between the Response Spectrum curves of the present and draft codes.
The set of programs can be downloaded as a zipped file, IS1893-070623.zip # to your computer. The download in in zipped format -- unzip the file to a folder and start with the Excel sheet file you see in it. All the contents of the zipped file should be in one folder.
The Excel sheet is more or less self-explanatory. There is also instructions in IS1893Pgrm-Instructions.docx file included. In the Excel file’s ‘IS1893’ sheet, enter parameters corresponding to the same building for both the (1) Present code as well as for the (2) Draft code, in the cells marked yellow
The Excel sheet is more or less self-explanatory. There is also instructions in IS1893Pgrm-Instructions.docx file included. In the Excel file’s ‘IS1893’ sheet, enter parameters corresponding to the same building for both the (1) Present code as well as for the (2) Draft code, in the cells marked yellow
(click on the picture to enlarge)
If you wish to calculate Shear Velocity from soil profiles (as prescribed in the code), enter soil details in the table labelled “Soil Profile” (after reading the instructions pointed from it) and click the 'Update Vs' button. You may also otherwise enter the Vs value directly in the orange cell. A comparison of site classifications in the present code and the draft code can be better understood from the Table below
(click on the picture to enlarge)
Once you have entered the:
1) Time periods, and
2) Parameters for both the
a) Present code, as well as for the
b) Draft code,
and have entered all the parameters -- note that the cells meant for data entry are marked yellow, except cell for ‘Vs’, which is marked orange -- click the 'Read to process' button (see screen-shot above), in order to write all data to a text file. Make sure you have enabled the scripts in the Excel file by clicking the “Enable Content” button that pops up as soon as you open the Excel file.
1) Time periods, and
2) Parameters for both the
a) Present code, as well as for the
b) Draft code,
and have entered all the parameters -- note that the cells meant for data entry are marked yellow, except cell for ‘Vs’, which is marked orange -- click the 'Read to process' button (see screen-shot above), in order to write all data to a text file. Make sure you have enabled the scripts in the Excel file by clicking the “Enable Content” button that pops up as soon as you open the Excel file.
Next, run the included application file 'IS1893Convert-250523.exe' …
…which processes the written data from the text file and writes results to another text file. The program opens in a DOS command window and once the processing is over, waits for the user to close it with a “Press any key to close…” message.
Note: Of course, the program (and the excel sheet) is expected to be run on a Windows computer -- not from a smartphone. If the program fails to open, as it should be seen above, it may mean that your computer does not have the dot-NET SDK framework installed. You can install the framework directly from the Microsoft site: https://dotnet.microsoft.com/en-us/download/dotnet/thank-you/sdk-6.0.408-windows-x64-installer (see footnote**). And of course, make sure you've clicked the "Read to process" button on the Excel sheet before trying to run the 'IS1893Convert-250523.exe' program, and before proceeding with whether you need to install dot-NET SDK framework.
Once the application file 'IS1893Convert-250523.exe' has been run, click the 'Read back results' button on the Excel sheet to read the processed data back to the sheets.
You now have the detailed workout for static method, with all steps elaborated, in the sheet named "Worksheet" according to present code…
Once the application file 'IS1893Convert-250523.exe' has been run, click the 'Read back results' button on the Excel sheet to read the processed data back to the sheets.
You now have the detailed workout for static method, with all steps elaborated, in the sheet named "Worksheet" according to present code…
(click on the picture to enlarge)
...the draft code...
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...and comparison between the two.
(click on the picture to enlarge)
Since the present code has factors for seismic load case in the load combinations, while the draft code does not, suitable adjustments are made in the comparisons.
For a manual calculation of lateral storey loads, you can use the “Effective Ahx” and “Effective Ahy” for the present code, as well as the “Effective Ahx.Des” and “Effective Ahy.Des” for the Draft code, combined with the storey wise seismic mass, as per 7.3.2 of IS:1893-2016 and the storey wise distribution of lateral loads as per 7.6.3 of IS:1893-2016 (both valid and same for the Draft code as well), which you may then apply to your model. However, for automated methods, you can follow the procedure described below:
In the main worksheet named “IS1893”, the pink cells are all populated, which are parameters for the analysis packages of STAAD.Pro CE, ETABS 17 and MIDAS/Gen, for Static method…
For a manual calculation of lateral storey loads, you can use the “Effective Ahx” and “Effective Ahy” for the present code, as well as the “Effective Ahx.Des” and “Effective Ahy.Des” for the Draft code, combined with the storey wise seismic mass, as per 7.3.2 of IS:1893-2016 and the storey wise distribution of lateral loads as per 7.6.3 of IS:1893-2016 (both valid and same for the Draft code as well), which you may then apply to your model. However, for automated methods, you can follow the procedure described below:
In the main worksheet named “IS1893”, the pink cells are all populated, which are parameters for the analysis packages of STAAD.Pro CE, ETABS 17 and MIDAS/Gen, for Static method…
(click on the picture to enlarge)
...as well as for Response Spectrum Method for the same analysis packages.
(click on the picture to enlarge)
In the "RSCurve" worksheet, you can see the Response Spectrum Curves for both the present code as well as for the draft code superimposed for comparison...
(click on the picture to enlarge)
A slide presentation file### has been uploaded that takes you through the basic steps for using the draft codes for structural analysis
As of now only the lateral load analysis has been presented on the program. And it being only a draft code, there is no point spending time on a full fledged program covering most aspects of the draft code. And by the time you have read this, the last date to submit comments to BIS might be over, or the final version of the code would have been released
Please post feedbacks and point out any corrections, if caught your notice. Hope this program will help you do some random checks with different buildings to get a feel of how much the forces calculated by the draft code differs from the present code
*The PDF files of the
draft codes can also be downloaded from here ##
**This dot-NET framework was selected and downloaded from the list found the Microsoft webpage https://dotnet.microsoft.com/en-us/download/dotnet/6.0 The list seen can be used to select a suitable version in case you are using Windows 7 or earlier
# https://www.dropbox.com/s/fi8x2d8gy697ew3/IS1893-070623.zip?dl=0
##https://www.dropbox.com/s/on1tv07t82bkm6y/IS1893-Draft2023.zip?dl=0
###https://www.dropbox.com/s/iva3w8uv8ksyvd6/IS1893-draft2023.pdf?dl=0
Rahul Leslie
rahul.leslie.driq@gmail.com
June 2023
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