Hello aspirant, there are some factors that can determine your chances of getting into IITs. This year's cut off depends upon the parameters given below:
1. Total number of seats available in a college.
2. Reputation of that college and,
3. The previous year's cut off trends
4. If you are from the reserved or unreserved category.

So, following are the previous year's cut off patterns of the IITs for OBC (NC) Category, for civil engineering or structural engineering:
1. IIT BHU - 654 (2016)

2. IIT Madras - 846 (2018)

3. IIT Bombay - 608 (2018)

4. IIT Kharagpur- 666 (2017)

5. IIT Guwahati - 545 (2017)

6. IIT Kanpur - 644 ( 2016)

7. IIT Roorkee - 49.75

8. IIT Hyderabad - 711 (2017)

9. IIT Gandhinagar - 558 (2017)

10. IISc Bangalore - 777 and 771 (2018)

11. IIT (ISM) Dhanbad - 599 (2017)

12. IIT Delhi - (785- 660) [2017]

13. IIT BHU - 530 ( 2017)

So according to the data I have provided, you can get admissions into IIT BHU and IIT Gandhinagar as per previous year's cut off.

Whereas if you want to assess your chances in NITs for structural engineering, check these last year's cut off:
1. NIT Jalandhar - (548-490) [2018]
2. IIEST Shibpur - (640-564) [2018]
3. MNIT Jaipur - (646-612) [2018]
4. NIT Bhopal - 614 (2018)
5. MNNIT Allahabad - 673 (2018)

You can check other cut- offs at the given link:
https://www.google.com/amp/s/engineering.careers360.com/articles/gate-cutoff-for-nits/amp

If you want to get a more accurate prediction of the Colleges you can get, please visit the College Predictor , link given below:
http://bit.ly/2J9S0MN

All the best!
I hope this helps.