Design Service Life

GeoStorage® Design Life

Geosynthetic Reinforced Soil Integrated Bridge System Synthesis Report

Geosynthetic Reinforced Soil (GRS) technology consists of closely-spaced layers of geosynthetic reinforcement and compacted granular fill material. GRS has been used for a variety of earthwork applications since the U.S. Forest Service first used it to build walls for roads in steep mountain terrain in the 1970s. Since then, the technology has evolved into the GRS Integrated Bridge System (IBS), a fast, cost-effective method of bridge support that blends the roadway into the superstructure. GRS-IBS includes a reinforced soil foundation, a GRS abutment, and a GRS integrated approach. The application of IBS has several advantages. The system is easy to design and economically construct. It can be built in variable weather conditions with readily available labor, materials, and equipment and can easily be modified in the field. This method has significant value when employed for small, single span structures meeting the criteria described in this report.

As a result of the demonstrated performance of GRS-IBS, the technology was selected for the Federal Highway Administration’s (FHWA) Every Day Counts initiative, aimed at accelerating implementation of proven, market-ready technologies. This report is the second in a two-part series and provides the background and other supporting information to substantiate the design method of GRS-IBS. The first document is a manual covering the design and construction of GRS-IBS. This two-part document series designs GRS as a composite material with known and predictable performance and deformations. Both documents are a collaboration between many disciplines within FHWA: geotechnical, structural, hydraulic, maintenance, and pavement engineering.

Corrugated Steel Pipe (CSP) Service Life Standards

NYSDOT Design Manual: Section 8-45

https://www.dot.ny.gov/divisions/engineering/design/dqab/hdm/hdm-repository/rev28.pdf

Metal Loss Rate:	Zone 2 (South of Albany)	Zone 1 (North of Albany)
Galvanized:	4 mil/yr	2 mil/yr

Auminized- Add 25 yrs
16 gage = .064 inches = 64 mils
14 gage = .079 inches = 79 mils

Note: NYSDOT sets the design life at the point where there is 100% metal loss.

Example:

Design Life in Zone 1 for 16 gage galvanized pipe = 16 years

Design Life in Zone 1 for 14 gage galvanized pipe = 20 years

PennDOT Drainage Design: Chapter 10-45

ftp://ftp.dot.state.pa.us/public/bureaus/design/PUB13M/Chapters/Chap10.pdf
Metal Loss Rate:
Galvanized- 2 mil/yr
Auminized- 1 mil/yr
PennDOT Loading: HS-25
PennDOT Safety Factor: 1.3 at end of service life

Note: PennDOT uses the reduced metal thickness, cross sectional area and radius of gyration at the end of the service life to calculate the safety factor.

Example:
8 ga galv CSP properties reduce to 16 ga CSP in 50 years: 168 mil – (50 x 2 mil/yr) = 68 mil

12 ga galv CSP properties reduce to 16 ga CSP in 20 years: 109 mil – (20 x 2mil/yr)= 69 mil

CalTrans Design Manual: Culvert Structures Section 2.1.1.2.1 Metal Pipe

http://www.dot.ca.gov/hq/oppd/dib/dib83-02-2.htm#2-1-1-2-1

For all metal pipes maintenance free service life, with respect to corrosion and abrasion and/or durability, is the number of years from installation until the deterioration reaches the point of perforation at any location on the culvert.
http://www.dot.ca.gov/hq/oppd/hdm/pdf/chp0850.pdf

2. Use Figures 855.3A, 855.3B and 854.3C to determine the minimum thickness and limitation on theuse of steel, aluminum or aluminized steel (corrugated or spiral rib) pipe.

Example:
pH Stormwater = 6.0
Degree of Corrosiveness “Low” = 4,500 Table 5-3 Design Information Bulletin #83-01
Years to Perforation 16 gage Galvanized CSP = 17 years

Important Consideration

There is no published service life or structural data for perforated pipe. All published data pertains to solid, coated culvert pipes- the base steel coil hot-dipped in molten zinc or aluminum prior to perforation. Fully perforated CSP pipe has thirty 3/8” diameter holes per square foot, each with exposed base metal around the circumference. The metal loss will be faster and the allowable wall compression stress and pipe stiffness will be lower for any perforated CSP pipe than it will be for solid galvanized pipe.

From - "Service Life Evaluation of Corrugated Steel Pipe..." Transportation Research Board 2003 Paper presented by Corrpro Companies Inc and sponsored by NCSPA (National Corrugated Steel Pipe Association): http://www.elzly.com/docs/Service_Life_Evaluation_of_Corrugated_Steel_Pipe_Storm_Water_Detention_Systems_in_the_Metropolitan_DC_Area.pdf

"In fact, some systems are developed with a slotted pipe (undesirable from a corrosion perspective
as the edges corrode quicker than the coated material..."

Plastic Crate Design

William H. Gordon Assocs. v. Heritage Fellowship, United Church of Christ

...GC installed the rain tank, the tank collapsed. Engineer designed and GC installed a different storm water management system...The circuit court concluded that the rain tank collapse was the failure of the Engineer ...The Supreme Court (1) affirmed the judgement of the circuit court.