I’ve recently looked for free software related to civil engineering. To my surprise there is probably not any. There are several projects that could potentially be used in civil engineering but none of them is directly usable for that purpose. For example 2D drawing tools may be good enough for electrical or mechanical engineering but do not provide means required for drawing construction plans.
Perhaps most people working in the area of civil engineering have some access to professional tools and that is all they need. If your needs are different and you miss civil engineering free software, let me know.