Corrosion of Steel Pilings in Soils

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$Standard X-ray Diffraction Powder Patterns$

$Standard X-ray Diffraction Powder Patterns$

$Standard X-ray Diffraction$

Soil resistivity and pHSoil resistivity and pHElevationResistivitypHElevationResistivitypHfl312 to 302-.._._._Ohm-ctnMin. 43,600 (4-pin) ___.____._.....Max. 50,200 (4-pin) _______ _ ____Avg. 46,500 (4-pin)........ _.„_„....ft256-246 ________Ohm-cmMin 12,500 (4-pin) .... — —Max 16,500 (4r-pin) ____ — _ —Avg 13,900 (4-pin)__ __._.-___U12 to 192_. .-_-.-Min. 29,100 (4-pin)..... ..____.__..Max. 36,000 (4-pin) ......_______„Avg, 32,800 (4-pin) .._.____25H-236. _..._.. _Min 4,700 (4-pin) __. — ___ —Max 9,600 (4-pin) _ .„ — — — _Avg 6,900 (4-pin )._ _____312 to 182_.----_.Min. 23,800 (4-pin) .......__...._Max. 29,300 (4-pin) ...__.__.______Avg. 26,000 (4-pin) ____ ._.____.__256-226. .__.--_._Min 4,300 (4-pin).. _ __-._._Max 7,200 (4-pin) ___ _______.._Avg 6,200 (4-pin) _ _____312..............310-. ---_---_---306 _ _303— .--__-_--..-302.......------.302....... .......> 10,000 (Shepard Canes)> 10,000 (Shepard Canes). . _1 5,400 (Laboratory) ____„__> 4,000 (Laboratory) ...._____7,510 (Laboratory)3,000 (Shepard Caries) ______5.76.05. 4255..... — — —— -249__247_-_____-______246______________9,000 (Shepard Canes) ___2,400 (Laboratory) ___ _2,300 (Laboratory) _ _ _ _ _Min 1,700 (Shepard Canes). __Max 3,500 (Shepard Canes) _ _ _Avg 2,400 (Shepard Canes) _ _ _4 44 0Condition oj piles:Mill scale was intact over approximately 90 percent of the pile surfaces. In localized areas, whichwere predominant in the top 8-iii. section of thepiles, there was slight metal attack and shallowpitting, not exceeding 10 mils in depth. In anarea covering a width of about 2 ft between elevation 304 and 302.5 ft, there were isolated pits whichmeasured between 10 and 20 mils in depth, andthree pits between 20 and 28 mils. The averagereduction in pile thickness measured in the threemost corroded areas in this zone was between 3 and4 percent.d. Grenada Dam Spillway, Grenada, MississippiHistory:Two excavations were made to expose steel sheetpilings for examination on the north side and thesouth side of the upstream wingwalls of the GrenadaDam Spillway on the Yalobusha River. The pilingsconsisted of the arch-sheet type with a driving widthof 15 in. and a wall thickness of % in.Date piles driven: October 1948Date oj inspection: March 1960Age oj piling: 11,4 yearsUPSTREAM WINGWALL—NORTH SIDEPiling exposed: A 6.7 ft width of the wingwall wasexposed between elevation 251.5 and 246 ft.Surface elevation: 256 ftWater table elevation: Much below 246 ftSoil characteristics:256 to 246 ft: Fill material consisting of friablereddish brown clayey sand or silt loam with clodsof grayish sandy clay and patches of very fine yellowish brown sand throughout the pit. Gravel, stones,pieces of dark gray shale, and fine roots present.Condition oj piles:Mill scale was intact on about 20 percent of thepile surfaces. Approximately 60 percent of the surface was uniformly corroded to shallow depths andcontained many scattered pits which generallyranged in depth between 40 and 90 mils. A fewpits between 90 and 108 mils in depth were present.The deepest pits were mainly concentrated betweenelevation 248 and 247 ft. The deeper pits werehighly localized and were found under nodules of soilparticles which appeared to be cemented to the steeland were difficult to scrape away. Measurements ofthe three most corroded areas showed average reductions in the thickness of the piles of 16, 13, and 10percent.UPSTREAM WINGWALL—SOUTH SIDEPiling exposed: A 7-ft width of the pilings in thewingwall was exposed between elevation 251.5 and246 ft.Surface elevation: 256 ftWater table elevation: Much below 246 ftSoil characteristics:256 to 248 ft: Reddish brown fine sandy loam withclods of light gray clay dispersed throughout theprofile. This is a fill soil containing many fine roots.248 to 246: Mixture of fine rust colored very finelight yellow silty sand intermingled with pieces oflight gray shale.Elevationft256 to 246____-_ _ MinMaxAveSoil resistivity and pHResistivityOhm-cm5,900 (4-pin) __ ___ _8,000 (4-pin).. . .........7,000 (4-pin) ___________pH14
Elevationft256 to 236_____ __256 to 226------250248 5247246—— - —— _-„_Soil resistivity and pH — ContinuedMinMaxAvgMinMaxAvgMinMaxAvgResistivityOhm-cm3,400 (4-pin) __ __ __6,900 (4-pin)_-____ ___ _4,300 (4-pin)___________2,700 (4-pin)____________3,800 (4-pin)____________3,500 (4-pin)____________2,400 (Laboratorv) ___ _4,000 (Laboratorv) ______4,300 (Laboratory) _ _ _5,000 (Shepard Canes) _ _ _11,000 (Shepard Canes) __7,900 (Shepard Canes). __pR4 46 46. 9Condition of piles:251.5 to 248 ft: Mill scale was present over 70percent of the surface. Many highly localized pitscorroded about 15 percent of the surface, the remaining 85 percent of the surface was unaffected bycorrosion. Six pits were found between 100 and 172mils in depth, eight pits between 50 and 95 mils, andother pits measured less than 50 mils. The corrosionproducts and soil particles adhering to the steel inthis zone were easily scraped off.248 to 246: About 30 percent of the piling surfaceswere affected by scattered pits, the other areas beingunaffected by corrosion. Mill scale was intact overmore than 50 percent of the surface. The sevendeepest pits ranged between 105 and 160 mils indepth. Also present were 11 pits between 50 and 95mils and other pits less than 50 mils in depth. Theaverage reduction in wall thickness measured in thethree most corroded areas was between 12 and 19percent. In this zone, the soil particles were easilyscraped from the steel surfaces, but a black crust offerric oxide which was embedded in the pits wasdifficult to break away.e. Berwick Lock, Berwick, LouisianaHistory:Two excavations were made to expose steel pilingsin the cutoff walls on the west side and east side ofthe north end of the Berwick Lock which is locatedbetween the Lower Atchafalaya River and BerwickBay near Berwick, La. The arch-type sheet steelpilings had a driving width of 19% in. and a % in.wall thickness.Date piles driven: March 1949Date of inspection: April 1960Age of piling: 11.1 yearsNORTH END OF LOCK—WEST SIDEPiling exposed: A 5-ft width of pilings was exposedbetween elevation +3.5 to —1.5 ft. One side of thepilings which was uncoated, was totally exposed tothe soil environment. The other side of the pilings15had a coal tar coating and was exposed to water.Surface elevation: + 5 f tWater table elevation: —0.5 ftSoil characteristics:+ 5 to + 2 ft: Fill material consisting of a mixtureof gray and brown silty clay containing some graveland small shells.+ 2 to —1.5: Natural soil consisting of tight bluishgray impervious plastic clay with patches of tightbrown clay dispersed throughout the profile.Elevationft+ 5 to -5_+ 5 to —15_+ 5 to -25_-1__.0__--1.5-Soil resistivity and pHMinMaxAvgResistivityOhm-cm860 (4-pin) _.960 (4-pin) _.900 (4-pin)..Min 990 (4-pin).Max 1, 260 (4-pin).Avg 1, 190 (4-pin).Min 1, 380 (4-pin).Max 1, 550 (4-pin).Avg 1, 440 (4-pin).Min 680 (Shepard Canes),Max 950 (Shepard Canes) _Avg 820 (Shepard Canes).1, 000 (Shepard Canes).1,400 (Laboratory).„__1, 290 (Laboratory) ____850 (Shepard Canes) _800 (Shepard Canes).850 (Shepard Canes) _8. 58. 1Condition of piles:+ 3.5 to +1.5 ft: Mill scale was intact over 40percent of the surface. The remaining surface wasuniformly attacked and had many shallow pits lessthan 25 mils in depth, and some deeper pits. Afew pits ranged between 55 and 61 mils in depth,and many others ranged between 25 and 55 mils.The average reduction in wall thickness observed onthe three most corroded areas was between 6 and 8percent.+1.5 to —1.5 ft: Mill scale was intact over about60 percent of the surface. Slight uniform corrosionwas present on the remaining surface and there weremany pits which did not exceed 25 mils in depth.There was slight general metal attack and pittingover the entire coated side of the pilings which wasexposed on the water side. The river water had aresistivity of 2,500 ohm-cm, and a salt content of40 ppm.NORTH END OF LOCK—EAST SIDEPiling exposed: A 5 ft width of the wall was exposedbetween elevation +3.5 and 0 ft.Surface elevation: + 5 f tWater table elevation: + 1 f tSoil characteristics:+ 5 to + 3 ft: Fill consisting of a mixture of slightly
Page 1 and 2: ScienceDocs.NBS MONOGRAPH 58Corrosi
Page 3 and 4: UNITED STATES DEPARTMENT OF COMMERC
Page 5 and 6: Corrosion of Steel Pilings in Soils
Page 7 and 8: exposure, 0.005 in./yr for wetting
Page 9 and 10: 4.1. Extracted Pilesa. Bonnet Carre
Page 11 and 12: The pile was a shallow-arch sheet p
Page 13 and 14: Condition of piles:Metal attack occ
Page 15 and 16: mils. A maximum reduction in pile c
Page 17: ElevationSoil resistivity and pHRes
Page 21: 290.5 to 282.5 : Reddish brown coar
Page 24 and 25: exposure in the laboratory under ae
Page 26 and 27: level or in the water table zone. A

Corrosion of Steel Pilings in Soils

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