You can choose the topic as per your interest. These are the three main sub branches of civil engineering.1) Environmental engineering
2) Geotechnical engineering
3) Structural engineeringFor environmental engineering-
There are options for you like NCAOR, NIO, NGRI etc.

For Geotechnical engineering-There are options for you like Larsen and Toubro, DMR, HMR

For Structural engineering-

You can go for Larsen and Toubro, RITES limited

Good Luck!