Chapter 8: Concrete dams

Chapter 8 addresses all types of concrete dams, including concrete gravity dams, roller-compacted concrete (RCC) dams, arch dams, buttress dams and faced symmetrical hardfill dams (FSHDs).

Since the 1980s, the construction of RCC dams has increased very rapidly, and less than 40 years later there are approximately 1000 RCC dams, either completed or under construction, in over 50 countries around the world. These dams are up to 250 m high and 7.5 million m3 in volume. For all concrete dams, a good rock foundation is needed – particularly one where there are no drastic changes in geological layers within the footprint of the dam.

FSHDs consist of RCC with low Portland cement content, that has the mechanical properties of a lean concrete. Over the past three decades FSHDs have become popular due to their economy, simplicity and adaptability to less than ideal local conditions. They are particularly economical when there is a less than good foundation and where there is high dynamic loading.

Methods of analysis are discussed, with particular reference to dam-water and dam-water-foundation interactions. Comments are offered on software requirements for two- and three-dimensional finite element analyses.

If the analyses are simplified by ignoring the mass of the foundation rock, the increase in overall damping due to foundation damping – material and radiation – is implicitly ignored, resulting in overestimation of earthquake response by factors of 2 to 3.