Page 310 - Buried Pipe Design

Rigid Pipe Products 281

Soil-Pipe Interaction Design and Analysis
(SPIDA)
Another computer program that has been developed for the design and
analysis of buried concrete pipe is named SPIDA. The SPIDA program
is owned and made available by the American Concrete Pipe
Association. SPIDA was developed as a fundamental analysis tool for
determining the earth loads and pressure distribution on a buried con-
crete pipe having a wide variety of embedment soils, backfill, and nat-
ural soils around and over the pipe.
The program has versatile capability for soil-structure interaction
analysis and design of buried concrete pipe installations. Its more sig-
nificant capabilities and limitations are as follows:
1. The program is capable of analysis and design of circumferential
structural effects in a buried circular concrete pipe.
2. It is limited to circular pipe with constant wall thickness.
3. It assumes installations are symmetric about a vertical plane.
4. It is capable of analyzing both trench and embankment installa-
tions; sloping trench walls are approximated with the use of steps
in the finite element mesh.
5. It is capable of providing pipe designs with the following reinforce-
ment cage arrangements:
■ Nonreinforced pipe
■ Single circular
■ Double circular
■ Single elliptical
■ Combination of circular plus elliptical
■ Combination of circular plus Mat at invert, or Mats at invert and
crown, or Mats at invert, crown, and spring line
6. Surface loads may include AASHTO HS-series and interstate
trucks, Cooper E-series railroad, user-specified concentrated and
uniformly distributed surcharge.
7. Fluid effects may include specified unit weight of fluid in full
pipe and internal pressure [up to maximum head of 50 ft (21.7
2
lb/in )].
8. The program is capable of providing pipe designs at intermediate
levels of backfill height in a single computer run.

Pipe system designers interested in using SPIDA should contact the
American Concrete Pipe Association.