Service Life of Culverts (2015) / Chapter Skim
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From page 111... ...
109 INTRODUCTION This appendix to NCHRP Project 20-05 Synthesis Topic 45-01, Service Life of Culverts, provides a summary of the most commonly accepted independent (i.e., not published by a pipe trade organization) quantitative service life calculation methods for concrete and metal pipes.
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From page 112... ...
110 where: EMSL = estimated material service life (years) , pH = pH of the water, Slope = pipe invert slope (%)
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111 pH = pH of the water, Slope = pipe invert slope (%) , Sediment = sediment depth in pipe invert (inches)
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112 FIGURE B1 Estimated service life versus pH and resistivity for 60-in.-diameter concrete culverts, S = 1,500 ppm (FDOT 2012)
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From page 115... ...
113 METAL PIPE METHODS The design service life of corrugated metal pipes will normally be the period in years from installation until deterioration reaches the point of either perforation of any point on the culvert or some specified percent of metal loss. Different methods used to estimate service life use different definitions of service life.
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From page 116... ...
114 The resulting EMSL value must be multiplied by a factor depending on the gage thickness (Table B5)
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From page 117... ...
115 The resulting EMSL value must be multiplied by a factor depending on the gage thickness (Table B6)
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From page 118... ...
116 The resulting EMSL value must be multiplied by a factor depending on the gage thickness (Table B7)
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From page 119... ...
117 The resulting EMSL value must be multiplied by a factor depending on the gage thickness (Table B8)
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From page 121... ...
119 Utah DOT Method The Utah DOT method was published in 1977 and is based on a study of 58 pipe culvert installations that were evaluated for durability characteristics and assigned a pipe rating to aid in numerical analysis and correlation with environmental soil and water conditions. Minimum soil resistivity, pH, total soluble slats, and sulfate content are interdependent parameters affecting pipe corrosion.
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From page 122... ...
120 Additional Service Life Due to Coatings Additional service life due to protection by coatings is generally included by adding on a predetermined number of years to the calculated service life using one of the aforementioned methods. Predetermined service life add-on values depend on the abrasion characteristics and type of coating.
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From page 123... ...
121 For pH between 8.5 and 9.0: where R is the minimum resistivity (ohm-cm)
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From page 124... ...
122 TABLE B12 DESIGN SERVICE LIFE VERSUS PH AND RESISTIVITY FOR 16-GAGE ALUMINIZED STEEL CULVERT PIPE USING FDOT METHOD (FDOT 2012) Aluminum Pipe Estimates of service life for aluminum pipe can be made based on an FDOT method, applied through the use of Figure B8 or Table B13.
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From page 125... ...
123 FIGURE B8 Estimated service life versus pH and resistivity for aluminum using FDOT method (FDOT 2012)
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