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Introduction. Loads acting on buried structures include the dead load of the struc­ture itself, the dead load of the earth cover over the structure, the weight of the fluid within the structure, live loads from vehicles, and, under certain circumstances, exter­nal hydrostatic pressure from groundwater. The structure dead load is only significant for rigid structures. […]

5.8.1 General Considerations The structural capacity of an underground structure and the methods of determining that capacity are dependent upon the material properties of the structure and its physical configuration. In this context, the structure is the composite structure comprised of the pipe and the surrounding soil. The surrounding soil is generally referred to as […]

The following general guidelines from the Federal Lands Highway (FLH) manual should assist in determining appropriate culvert material types and necessary coatings. Other methods are available. Many state departments of transportation and local governmental agencies have published durability criteria, and this information should be used where available. A materials engineer should be consulted for important […]

Abrasion causes a loss of section thickness due to impacts by the aggregate carried by stream flow. Protection from abrasion generally takes the form of providing a sacrifi­cial thickness of the structural material, whether it be a thicker sheet of steel or con­crete paved invert for metal pipe, or more concrete cover over the reinforcement […]

Important environmental factors that affect culvert durability include the acidity (pH) of the effluent and the soil, the electrical resistivity of the effluent and the soil, and the concentration of sulfates and chlorides. Data on these factors should be obtained at each pipe location, unless a random sampling plan is justified by establishing that the […]

The prediction of service life of drainage facilities is difficult because of the wide range of environments encountered and the various protective measures available. Service life and durability are directly related to resistance to corrosion, abrasion, and other modes of deterioration. 5.7.1 Design Service Life Drainage facilities are usually designed for a specific service life. […]

Numerous drainage products are available in steel with protective coatings and in aluminum. These include corrugated pipe, spiral-rib pipe, structural-plate pipe, box cul­verts, and, where a tunnel is required, tunnel liner plates. Figure 5.24 shows the variety of profiles available for the wall cross-section of steel drainage products. For additional profiles, see “Corrugated Steel Pipe […]

The main types of pipe used in highway construction are concrete pipe, metal pipe (steel or aluminum), and plastic pipe (high-density polyethylene and polyvinyl chloride). They are available in a wide array of sizes, shapes, and properties. Table 5.10 gives the ASTM and AASHTO standards for the most common highway drainage pipes. Some of the […]

Because of its hydraulic characteristics, the outlet velocity of a culvert is usually higher than the velocity in the discharge channel. The outlet velocity may be calculated either using Manning’s equation, Eq. (5.11), if the culvert is under inlet control, or by divid­ing the discharge by the cross-sectional area of the flow if under outlet […]

Because culvert shapes are so numerous and new shapes are often developed, design charts showing performance curves are not available for all culvert sizes and shapes. One example is long-span corrugated-metal sectional plate structures. Although the product is available in several cross-sectional shapes, performance curves are avail­able only for circular or elliptical cross-sections (Fig. 5.17) […]