Bridge design is one small subset of civil engineering.  Civil engineering is a broad umbrella of disciplines that covers the design of all the infrastructure that makes modern civilization possible.  Among the branches of civil engineering are:

structural (includng bridge design)
environmental
geotechnical
transportation
water resources

The term civil engineering was coined in the 18th century to distinguish this type of engineering from military engineering.

I should add that although Civil Engineering encompasses many subdisciplines as listed above, in current U.S. practice the term Civil Engineer is most often applied to someone who does not specialize in any of the subdisciplines.  So a Civil Engineer is often someone who does grading, drainage, utility layout, etc.  Specialists in Structural Engineering prefer to call themselves Structural Engineers, specialists in Geotechnical Engineering prefer the term Geotechnical Engineer, etc.

To quote the old "motto" of the Institution Of Civil Engineers "Civil Engineers are those who harness the power of nature for the benefit of mankind".

One of my favourite quotes as to the benefit to society that we civil engineers hold in our power comes from the late great Owen Williams who once said "An engineer will do for a shilling what any fool can do for a pound".  Although one may read this the wrong way, I feel that this pretty much hits the nail on the head.

Andy Machon

 
 

Ginger, that old saying translated for the US has always been: An engineer does for a dollar what any old farmer can do for two.

I guess those expression with some truth to them find national and international longevity!

well as far as the Question that the  one who builds Bridges is a Civil Engineer or not is that U can say that its just like a simple Doctor can not perform a Heart Surgery a heart surgean n a whole lot of staf is reqd same is with building a bridge is , one needs a Struc Engr, Soil Engr. etc who all are the specialized fields of Civil Engr.
Regards
Rednyx