Technical Manual: Conduits through Embankment Dams (FEMA 484)

Chapter 2Conduit MaterialsVarious materials have been used in the design and construction of conduits throughembankment dams. The reasons for utilizing these different materials have includedcost, availability, operations, maintenance, and constructability. The most commonmaterials used in the construction of new and renovated conduits have been:• Concrete.—Reinforced cast-in place and precast• Plastic.—Thermoplastic and thermoset• Metal.—Steel, ductile iron, cast iron, and CMPThe strength and performance characteristics of each conduit material depend on itschemistry and the relationship of its components. For example, concrete isproduced using cement, sand, aggregates, and reinforcement, whereas metal is ahomogenous, isotropic material.Certain design and construction advantages and disadvantages are associated witheach material. Each material requires specific design and constructionconsiderations. Some of these materials, are not recommended for use in the designand construction of conduits through significant and high hazard embankmentdams. For example, CMP is seldom used in any embankment dams other than lowhazard dams and needs to be carefully evaluated for the specific dam site. Forguidance on the use of specific materials in renovation, replacement, and repair ofconduits, see chapters 12, 13, and 14.2.1 ConcreteConcrete materials used in conduit construction have included:• Reinforced cast-in-place• Precast concrete pipe41