[{"data":1,"prerenderedAt":2262},["ShallowReactive",2],{"blog-\u002Fblog\u002Fsight-rails-boning-rods-grading":3,"blog-surround-\u002Fblog\u002Fsight-rails-boning-rods-grading":2251},{"id":4,"title":5,"author":6,"body":7,"category":2220,"description":2221,"extension":2222,"image":2223,"meta":2224,"navigation":2243,"path":2244,"publishedAt":2245,"readTime":2246,"seo":2247,"sitemap":2248,"stem":2249,"__hash__":2250},"blog\u002Fblog\u002F19.sight-rails-boning-rods-grading.md","Sight Rails and Boning Rods: Practical Dimensional Control for Grading","Surveyiiing Expert",{"type":8,"value":9,"toc":2195},"minimark",[10,15,33,37,43,47,52,56,61,211,760,764,957,961,1167,1171,1177,1389,2030,2034,2062,2066,2087,2091,2120,2124,2183,2187],[11,12,14],"h2",{"id":13},"overview","Overview",[16,17,18,19,23,24,27,28,32],"p",{},"In civil engineering, maintaining a constant gradient is vital for gravity-fed systems like sewers and storm drains. While modern lasers are common, the foundational method of ",[20,21,22],"strong",{},"Sight Rails (SR)"," and ",[20,25,26],{},"Boning Rods"," (or Travellers) remains a robust, fail-safe field technique for ensuring excavation reaches the correct \"formation level\" ",[29,30,31],"span",{},"14, 15",".",[11,34,36],{"id":35},"why-this-matters","Why This Matters",[16,38,39,40,32],{},"If a sewer pipe is laid even slightly off-grade, it will result in \"ponding\" or blockages. Sight rails provide a physical, visual line of sight that workers can use to check the depth of a trench at any point along its length without needing a surveyor constantly on-station ",[29,41,42],{},"14",[11,44,46],{"id":45},"theory","Theory",[16,48,49,50,32],{},"A gradient is established by fixing two horizontal cross-boards (Sight Rails) at known elevations above the proposed trench bottom. A T-shaped rod of a fixed length (the Boning Rod) is then held in the trench. If the top of the rod aligns perfectly with the line of sight between the two rails, the trench is at the correct depth ",[29,51,31],{},[11,53,55],{"id":54},"mathematical-principles","Mathematical Principles",[57,58,60],"h3",{"id":59},"calculating-sight-rail-heights","Calculating Sight Rail Heights",[16,62,63,64,210],{},"To set a rail, you must determine its height above a local peg (",[29,65,68,114],{"className":66},[67],"katex",[29,69,72],{"className":70},[71],"katex-mathml",[73,74,76],"math",{"xmlns":75},"http:\u002F\u002Fwww.w3.org\u002F1998\u002FMath\u002FMathML",[77,78,79,109],"semantics",{},[80,81,82,86,89],"mrow",{},[83,84,85],"mi",{},"P",[83,87,88],{},"e",[90,91,92,95],"msub",{},[83,93,94],{},"g",[80,96,97,100,102,105,107],{},[83,98,99],{},"l",[83,101,88],{},[83,103,104],{},"v",[83,106,88],{},[83,108,99],{},[110,111,113],"annotation",{"encoding":112},"application\u002Fx-tex","Peg_{level}",[29,115,119],{"className":116,"ariaHidden":118},[117],"katex-html","true",[29,120,123,128,134,137],{"className":121},[122],"base",[29,124],{"className":125,"style":127},[126],"strut","height:0.8778em;vertical-align:-0.1944em;",[29,129,85],{"className":130,"style":133},[131,132],"mord","mathnormal","margin-right:0.1389em;",[29,135,88],{"className":136},[131,132],[29,138,140,144],{"className":139},[131],[29,141,94],{"className":142,"style":143},[131,132],"margin-right:0.0359em;",[29,145,148],{"className":146},[147],"msupsub",[29,149,153,201],{"className":150},[151,152],"vlist-t","vlist-t2",[29,154,157,196],{"className":155},[156],"vlist-r",[29,158,162],{"className":159,"style":161},[160],"vlist","height:0.3361em;",[29,163,165,170],{"style":164},"top:-2.55em;margin-left:-0.0359em;margin-right:0.05em;",[29,166],{"className":167,"style":169},[168],"pstrut","height:2.7em;",[29,171,177],{"className":172},[173,174,175,176],"sizing","reset-size6","size3","mtight",[29,178,180,184,187,190,193],{"className":179},[131,176],[29,181,99],{"className":182,"style":183},[131,132,176],"margin-right:0.0197em;",[29,185,88],{"className":186},[131,132,176],[29,188,104],{"className":189,"style":143},[131,132,176],[29,191,88],{"className":192},[131,132,176],[29,194,99],{"className":195,"style":183},[131,132,176],[29,197,200],{"className":198},[199],"vlist-s","​",[29,202,204],{"className":203},[156],[29,205,208],{"className":206,"style":207},[160],"height:0.15em;",[29,209],{},").",[212,213,214,261,383,554],"ol",{},[215,216,217,258,259,32],"li",{},[20,218,219,220,257],{},"Determine Formation Level (",[29,221,223,241],{"className":222},[67],[29,224,226],{"className":225},[71],[73,227,228],{"xmlns":75},[77,229,230,238],{},[80,231,232,235],{},[83,233,234],{},"F",[83,236,237],{},"L",[110,239,240],{"encoding":112},"FL",[29,242,244],{"className":243,"ariaHidden":118},[117],[29,245,247,251,254],{"className":246},[122],[29,248],{"className":249,"style":250},[126],"height:0.6833em;",[29,252,234],{"className":253,"style":133},[131,132],[29,255,237],{"className":256},[131,132],"):"," Calculated from the design gradient ",[29,260,42],{},[215,262,263,296,297,340,341,379,380,32],{},[20,264,265,266,257],{},"Select Rod Length (",[29,267,269,283],{"className":268},[67],[29,270,272],{"className":271},[71],[73,273,274],{"xmlns":75},[77,275,276,281],{},[80,277,278],{},[83,279,280],{},"R",[110,282,280],{"encoding":112},[29,284,286],{"className":285,"ariaHidden":118},[117],[29,287,289,292],{"className":288},[122],[29,290],{"className":291,"style":250},[126],[29,293,280],{"className":294,"style":295},[131,132],"margin-right:0.0077em;"," Usually a round number like ",[29,298,300,320],{"className":299},[67],[29,301,303],{"className":302},[71],[73,304,305],{"xmlns":75},[77,306,307,317],{},[80,308,309,313],{},[310,311,312],"mn",{},"3.0",[314,315,316],"mtext",{}," m",[110,318,319],{"encoding":112},"3.0\\text{ m}",[29,321,323],{"className":322,"ariaHidden":118},[117],[29,324,326,330,333],{"className":325},[122],[29,327],{"className":328,"style":329},[126],"height:0.6444em;",[29,331,312],{"className":332},[131],[29,334,337],{"className":335},[131,336],"text",[29,338,316],{"className":339},[131]," or ",[29,342,344,361],{"className":343},[67],[29,345,347],{"className":346},[71],[73,348,349],{"xmlns":75},[77,350,351,358],{},[80,352,353,356],{},[310,354,355],{},"3.5",[314,357,316],{},[110,359,360],{"encoding":112},"3.5\\text{ m}",[29,362,364],{"className":363,"ariaHidden":118},[117],[29,365,367,370,373],{"className":366},[122],[29,368],{"className":369,"style":329},[126],[29,371,355],{"className":372},[131],[29,374,376],{"className":375},[131,336],[29,377,316],{"className":378},[131]," ",[29,381,382],{},"15",[215,384,385,379,492,32],{},[20,386,387,388,257],{},"Required Rail Level (",[29,389,391,422],{"className":390},[67],[29,392,394],{"className":393},[71],[73,395,396],{"xmlns":75},[77,397,398,419],{},[80,399,400,403],{},[83,401,402],{},"S",[90,404,405,407],{},[83,406,280],{},[80,408,409,411,413,415,417],{},[83,410,99],{},[83,412,88],{},[83,414,104],{},[83,416,88],{},[83,418,99],{},[110,420,421],{"encoding":112},"SR_{level}",[29,423,425],{"className":424,"ariaHidden":118},[117],[29,426,428,432,436],{"className":427},[122],[29,429],{"className":430,"style":431},[126],"height:0.8333em;vertical-align:-0.15em;",[29,433,402],{"className":434,"style":435},[131,132],"margin-right:0.0576em;",[29,437,439,442],{"className":438},[131],[29,440,280],{"className":441,"style":295},[131,132],[29,443,445],{"className":444},[147],[29,446,448,484],{"className":447},[151,152],[29,449,451,481],{"className":450},[156],[29,452,454],{"className":453,"style":161},[160],[29,455,457,460],{"style":456},"top:-2.55em;margin-left:-0.0077em;margin-right:0.05em;",[29,458],{"className":459,"style":169},[168],[29,461,463],{"className":462},[173,174,175,176],[29,464,466,469,472,475,478],{"className":465},[131,176],[29,467,99],{"className":468,"style":183},[131,132,176],[29,470,88],{"className":471},[131,132,176],[29,473,104],{"className":474,"style":143},[131,132,176],[29,476,88],{"className":477},[131,132,176],[29,479,99],{"className":480,"style":183},[131,132,176],[29,482,200],{"className":483},[199],[29,485,487],{"className":486},[156],[29,488,490],{"className":489,"style":207},[160],[29,491],{},[29,493,495,517],{"className":494},[67],[29,496,498],{"className":497},[71],[73,499,500],{"xmlns":75},[77,501,502,514],{},[80,503,504,506,508,512],{},[83,505,234],{},[83,507,237],{},[509,510,511],"mo",{},"+",[83,513,280],{},[110,515,516],{"encoding":112},"FL + R",[29,518,520,545],{"className":519,"ariaHidden":118},[117],[29,521,523,527,530,533,538,542],{"className":522},[122],[29,524],{"className":525,"style":526},[126],"height:0.7667em;vertical-align:-0.0833em;",[29,528,234],{"className":529,"style":133},[131,132],[29,531,237],{"className":532},[131,132],[29,534],{"className":535,"style":537},[536],"mspace","margin-right:0.2222em;",[29,539,511],{"className":540},[541],"mbin",[29,543],{"className":544,"style":537},[536],[29,546,548,551],{"className":547},[122],[29,549],{"className":550,"style":250},[126],[29,552,280],{"className":553,"style":295},[131,132],[215,555,556,379,559,379,758,32],{},[20,557,558],{},"Height above Peg:",[29,560,562,615],{"className":561},[67],[29,563,565],{"className":564},[71],[73,566,567],{"xmlns":75},[77,568,569,612],{},[80,570,571,573,589,592,594,596],{},[83,572,402],{},[90,574,575,577],{},[83,576,280],{},[80,578,579,581,583,585,587],{},[83,580,99],{},[83,582,88],{},[83,584,104],{},[83,586,88],{},[83,588,99],{},[509,590,591],{},"−",[83,593,85],{},[83,595,88],{},[90,597,598,600],{},[83,599,94],{},[80,601,602,604,606,608,610],{},[83,603,99],{},[83,605,88],{},[83,607,104],{},[83,609,88],{},[83,611,99],{},[110,613,614],{"encoding":112},"SR_{level} - Peg_{level}",[29,616,618,691],{"className":617,"ariaHidden":118},[117],[29,619,621,624,627,682,685,688],{"className":620},[122],[29,622],{"className":623,"style":431},[126],[29,625,402],{"className":626,"style":435},[131,132],[29,628,630,633],{"className":629},[131],[29,631,280],{"className":632,"style":295},[131,132],[29,634,636],{"className":635},[147],[29,637,639,674],{"className":638},[151,152],[29,640,642,671],{"className":641},[156],[29,643,645],{"className":644,"style":161},[160],[29,646,647,650],{"style":456},[29,648],{"className":649,"style":169},[168],[29,651,653],{"className":652},[173,174,175,176],[29,654,656,659,662,665,668],{"className":655},[131,176],[29,657,99],{"className":658,"style":183},[131,132,176],[29,660,88],{"className":661},[131,132,176],[29,663,104],{"className":664,"style":143},[131,132,176],[29,666,88],{"className":667},[131,132,176],[29,669,99],{"className":670,"style":183},[131,132,176],[29,672,200],{"className":673},[199],[29,675,677],{"className":676},[156],[29,678,680],{"className":679,"style":207},[160],[29,681],{},[29,683],{"className":684,"style":537},[536],[29,686,591],{"className":687},[541],[29,689],{"className":690,"style":537},[536],[29,692,694,697,700,703],{"className":693},[122],[29,695],{"className":696,"style":127},[126],[29,698,85],{"className":699,"style":133},[131,132],[29,701,88],{"className":702},[131,132],[29,704,706,709],{"className":705},[131],[29,707,94],{"className":708,"style":143},[131,132],[29,710,712],{"className":711},[147],[29,713,715,750],{"className":714},[151,152],[29,716,718,747],{"className":717},[156],[29,719,721],{"className":720,"style":161},[160],[29,722,723,726],{"style":164},[29,724],{"className":725,"style":169},[168],[29,727,729],{"className":728},[173,174,175,176],[29,730,732,735,738,741,744],{"className":731},[131,176],[29,733,99],{"className":734,"style":183},[131,132,176],[29,736,88],{"className":737},[131,132,176],[29,739,104],{"className":740,"style":143},[131,132,176],[29,742,88],{"className":743},[131,132,176],[29,745,99],{"className":746,"style":183},[131,132,176],[29,748,200],{"className":749},[199],[29,751,753],{"className":752},[156],[29,754,756],{"className":755,"style":207},[160],[29,757],{},[29,759,42],{},[57,761,763],{"id":762},"gradient-divergence","Gradient Divergence",[16,765,766,767,813,814,844,845,883,884,379,955,32],{},"For a gradient of ",[29,768,770,791],{"className":769},[67],[29,771,773],{"className":772},[71],[73,774,775],{"xmlns":75},[77,776,777,788],{},[80,778,779,782,785],{},[310,780,781],{},"1",[314,783,784],{}," in ",[83,786,787],{},"N",[110,789,790],{"encoding":112},"1 \\text{ in } N",[29,792,794],{"className":793,"ariaHidden":118},[117],[29,795,797,800,803,809],{"className":796},[122],[29,798],{"className":799,"style":250},[126],[29,801,781],{"className":802},[131],[29,804,806],{"className":805},[131,336],[29,807,784],{"className":808},[131],[29,810,787],{"className":811,"style":812},[131,132],"margin-right:0.109em;"," over distance ",[29,815,817,831],{"className":816},[67],[29,818,820],{"className":819},[71],[73,821,822],{"xmlns":75},[77,823,824,829],{},[80,825,826],{},[83,827,828],{},"D",[110,830,828],{"encoding":112},[29,832,834],{"className":833,"ariaHidden":118},[117],[29,835,837,840],{"className":836},[122],[29,838],{"className":839,"style":250},[126],[29,841,828],{"className":842,"style":843},[131,132],"margin-right:0.0278em;",", the change in elevation (",[29,846,848,867],{"className":847},[67],[29,849,851],{"className":850},[71],[73,852,853],{"xmlns":75},[77,854,855,864],{},[80,856,857,861],{},[83,858,860],{"mathvariant":859},"normal","Δ",[83,862,863],{},"H",[110,865,866],{"encoding":112},"\\Delta H",[29,868,870],{"className":869,"ariaHidden":118},[117],[29,871,873,876,879],{"className":872},[122],[29,874],{"className":875,"style":250},[126],[29,877,860],{"className":878},[131],[29,880,863],{"className":881,"style":882},[131,132],"margin-right:0.0813em;",") is:\n",[29,885,887,913],{"className":886},[67],[29,888,890],{"className":889},[71],[73,891,892],{"xmlns":75},[77,893,894,910],{},[80,895,896,898,900,903,905,908],{},[83,897,860],{"mathvariant":859},[83,899,863],{},[509,901,902],{},"=",[83,904,828],{},[83,906,907],{"mathvariant":859},"\u002F",[83,909,787],{},[110,911,912],{"encoding":112},"\\Delta H = D \u002F N",[29,914,916,939],{"className":915,"ariaHidden":118},[117],[29,917,919,922,925,928,932,936],{"className":918},[122],[29,920],{"className":921,"style":250},[126],[29,923,860],{"className":924},[131],[29,926,863],{"className":927,"style":882},[131,132],[29,929],{"className":930,"style":931},[536],"margin-right:0.2778em;",[29,933,902],{"className":934},[935],"mrel",[29,937],{"className":938,"style":931},[536],[29,940,942,946,949,952],{"className":941},[122],[29,943],{"className":944,"style":945},[126],"height:1em;vertical-align:-0.25em;",[29,947,828],{"className":948,"style":843},[131,132],[29,950,907],{"className":951},[131],[29,953,787],{"className":954,"style":812},[131,132],[29,956,42],{},[11,958,960],{"id":959},"field-workflow","Field Workflow",[962,963,964,968,1033,1037,1040,1044,1049,1053,1158,1162],"steps",{},[57,965,967],{"id":966},"offset-pegs","Offset Pegs",[16,969,970,971,23,1000,1030,1031,32],{},"Establish pegs (",[29,972,974,988],{"className":973},[67],[29,975,977],{"className":976},[71],[73,978,979],{"xmlns":75},[77,980,981,986],{},[80,982,983],{},[83,984,985],{},"A",[110,987,985],{"encoding":112},[29,989,991],{"className":990,"ariaHidden":118},[117],[29,992,994,997],{"className":993},[122],[29,995],{"className":996,"style":250},[126],[29,998,985],{"className":999},[131,132],[29,1001,1003,1017],{"className":1002},[67],[29,1004,1006],{"className":1005},[71],[73,1007,1008],{"xmlns":75},[77,1009,1010,1015],{},[80,1011,1012],{},[83,1013,1014],{},"B",[110,1016,1014],{"encoding":112},[29,1018,1020],{"className":1019,"ariaHidden":118},[117],[29,1021,1023,1026],{"className":1022},[122],[29,1024],{"className":1025,"style":250},[126],[29,1027,1014],{"className":1028,"style":1029},[131,132],"margin-right:0.0502em;",") offset a known distance from the trench center-line to ensure they aren't destroyed during excavation ",[29,1032,382],{},[57,1034,1036],{"id":1035},"determine-elevations","Determine Elevations",[16,1038,1039],{},"Level the pegs using a nearby Bench Mark (BM).",[57,1041,1043],{"id":1042},"calculate-rail-levels","Calculate Rail Levels",[16,1045,1046,1047,32],{},"Based on the design gradient and the selected boning rod length, calculate the required level for the sight rail boards ",[29,1048,42],{},[57,1050,1052],{"id":1051},"install-rails","Install Rails",[16,1054,1055,1056,1155,1156,32],{},"Fix horizontal boards (Sight Rails) to upright stakes. Ensure the top edge of each board is at the calculated ",[29,1057,1059,1088],{"className":1058},[67],[29,1060,1062],{"className":1061},[71],[73,1063,1064],{"xmlns":75},[77,1065,1066,1086],{},[80,1067,1068,1070],{},[83,1069,402],{},[90,1071,1072,1074],{},[83,1073,280],{},[80,1075,1076,1078,1080,1082,1084],{},[83,1077,99],{},[83,1079,88],{},[83,1081,104],{},[83,1083,88],{},[83,1085,99],{},[110,1087,421],{"encoding":112},[29,1089,1091],{"className":1090,"ariaHidden":118},[117],[29,1092,1094,1097,1100],{"className":1093},[122],[29,1095],{"className":1096,"style":431},[126],[29,1098,402],{"className":1099,"style":435},[131,132],[29,1101,1103,1106],{"className":1102},[131],[29,1104,280],{"className":1105,"style":295},[131,132],[29,1107,1109],{"className":1108},[147],[29,1110,1112,1147],{"className":1111},[151,152],[29,1113,1115,1144],{"className":1114},[156],[29,1116,1118],{"className":1117,"style":161},[160],[29,1119,1120,1123],{"style":456},[29,1121],{"className":1122,"style":169},[168],[29,1124,1126],{"className":1125},[173,174,175,176],[29,1127,1129,1132,1135,1138,1141],{"className":1128},[131,176],[29,1130,99],{"className":1131,"style":183},[131,132,176],[29,1133,88],{"className":1134},[131,132,176],[29,1136,104],{"className":1137,"style":143},[131,132,176],[29,1139,88],{"className":1140},[131,132,176],[29,1142,99],{"className":1143,"style":183},[131,132,176],[29,1145,200],{"className":1146},[199],[29,1148,1150],{"className":1149},[156],[29,1151,1153],{"className":1152,"style":207},[160],[29,1154],{}," using a level and staff ",[29,1157,31],{},[57,1159,1161],{"id":1160},"check-with-traveller","Check with Traveller",[16,1163,1164,1165,32],{},"As the trench is excavated, hold the boning rod (Traveller) vertically. Sight from one rail to the other; the trench is at grade when the rod's cross-head just touches the line of sight ",[29,1166,31],{},[11,1168,1170],{"id":1169},"step-by-step-example","Step-by-Step Example",[16,1172,1173,1176],{},[20,1174,1175],{},"Problem:"," Set a sight rail at Peg B.",[1178,1179,1180,1260,1347],"ul",{},[215,1181,1182,1183,1221,1222,32],{},"Peg A: Level ",[29,1184,1186,1203],{"className":1185},[67],[29,1187,1189],{"className":1188},[71],[73,1190,1191],{"xmlns":75},[77,1192,1193,1200],{},[80,1194,1195,1198],{},[310,1196,1197],{},"40.0",[314,1199,316],{},[110,1201,1202],{"encoding":112},"40.0\\text{ m}",[29,1204,1206],{"className":1205,"ariaHidden":118},[117],[29,1207,1209,1212,1215],{"className":1208},[122],[29,1210],{"className":1211,"style":329},[126],[29,1213,1197],{"className":1214},[131],[29,1216,1218],{"className":1217},[131,336],[29,1219,316],{"className":1220},[131],", Distance to B = ",[29,1223,1225,1242],{"className":1224},[67],[29,1226,1228],{"className":1227},[71],[73,1229,1230],{"xmlns":75},[77,1231,1232,1239],{},[80,1233,1234,1237],{},[310,1235,1236],{},"50",[314,1238,316],{},[110,1240,1241],{"encoding":112},"50\\text{ m}",[29,1243,1245],{"className":1244,"ariaHidden":118},[117],[29,1246,1248,1251,1254],{"className":1247},[122],[29,1249],{"className":1250,"style":329},[126],[29,1252,1236],{"className":1253},[131],[29,1255,1257],{"className":1256},[131,336],[29,1258,316],{"className":1259},[131],[215,1261,1262,1263,1301,1302,1346],{},"Design: Formation level at A is ",[29,1264,1266,1283],{"className":1265},[67],[29,1267,1269],{"className":1268},[71],[73,1270,1271],{"xmlns":75},[77,1272,1273,1280],{},[80,1274,1275,1278],{},[310,1276,1277],{},"38.0",[314,1279,316],{},[110,1281,1282],{"encoding":112},"38.0\\text{ m}",[29,1284,1286],{"className":1285,"ariaHidden":118},[117],[29,1287,1289,1292,1295],{"className":1288},[122],[29,1290],{"className":1291,"style":329},[126],[29,1293,1277],{"className":1294},[131],[29,1296,1298],{"className":1297},[131,336],[29,1299,316],{"className":1300},[131],", Gradient is ",[29,1303,1305,1324],{"className":1304},[67],[29,1306,1308],{"className":1307},[71],[73,1309,1310],{"xmlns":75},[77,1311,1312,1321],{},[80,1313,1314,1316,1318],{},[310,1315,781],{},[314,1317,784],{},[310,1319,1320],{},"200",[110,1322,1323],{"encoding":112},"1 \\text{ in } 200",[29,1325,1327],{"className":1326,"ariaHidden":118},[117],[29,1328,1330,1334,1337,1343],{"className":1329},[122],[29,1331],{"className":1332,"style":1333},[126],"height:0.6679em;",[29,1335,781],{"className":1336},[131],[29,1338,1340],{"className":1339},[131,336],[29,1341,784],{"className":1342},[131],[29,1344,1320],{"className":1345},[131]," (rising).",[215,1348,1349,1350,1386,1387,32],{},"Tool: Use a ",[29,1351,1353,1368],{"className":1352},[67],[29,1354,1356],{"className":1355},[71],[73,1357,1358],{"xmlns":75},[77,1359,1360,1366],{},[80,1361,1362,1364],{},[310,1363,355],{},[314,1365,316],{},[110,1367,360],{"encoding":112},[29,1369,1371],{"className":1370,"ariaHidden":118},[117],[29,1372,1374,1377,1380],{"className":1373},[122],[29,1375],{"className":1376,"style":329},[126],[29,1378,355],{"className":1379},[131],[29,1381,1383],{"className":1382},[131,336],[29,1384,316],{"className":1385},[131]," boning rod ",[29,1388,31],{},[212,1390,1391,1674,1904],{},[215,1392,1393,1430,1521],{},[20,1394,1395,1396,1429],{},"Calculate ",[29,1397,1399,1414],{"className":1398},[67],[29,1400,1402],{"className":1401},[71],[73,1403,1404],{"xmlns":75},[77,1405,1406,1412],{},[80,1407,1408,1410],{},[83,1409,234],{},[83,1411,237],{},[110,1413,240],{"encoding":112},[29,1415,1417],{"className":1416,"ariaHidden":118},[117],[29,1418,1420,1423,1426],{"className":1419},[122],[29,1421],{"className":1422,"style":250},[126],[29,1424,234],{"className":1425,"style":133},[131,132],[29,1427,237],{"className":1428},[131,132]," at B:",[29,1431,1433,1463],{"className":1432},[67],[29,1434,1436],{"className":1435},[71],[73,1437,1438],{"xmlns":75},[77,1439,1440,1460],{},[80,1441,1442,1445,1447,1449,1451,1453,1455,1458],{},[314,1443,1444],{},"Rise",[509,1446,902],{},[310,1448,1236],{},[83,1450,907],{"mathvariant":859},[310,1452,1320],{},[509,1454,902],{},[310,1456,1457],{},"0.25",[314,1459,316],{},[110,1461,1462],{"encoding":112},"\\text{Rise} = 50 \u002F 200 = 0.25\\text{ m}",[29,1464,1466,1487,1506],{"className":1465,"ariaHidden":118},[117],[29,1467,1469,1472,1478,1481,1484],{"className":1468},[122],[29,1470],{"className":1471,"style":250},[126],[29,1473,1475],{"className":1474},[131,336],[29,1476,1444],{"className":1477},[131],[29,1479],{"className":1480,"style":931},[536],[29,1482,902],{"className":1483},[935],[29,1485],{"className":1486,"style":931},[536],[29,1488,1490,1493,1497,1500,1503],{"className":1489},[122],[29,1491],{"className":1492,"style":945},[126],[29,1494,1496],{"className":1495},[131],"50\u002F200",[29,1498],{"className":1499,"style":931},[536],[29,1501,902],{"className":1502},[935],[29,1504],{"className":1505,"style":931},[536],[29,1507,1509,1512,1515],{"className":1508},[122],[29,1510],{"className":1511,"style":329},[126],[29,1513,1457],{"className":1514},[131],[29,1516,1518],{"className":1517},[131,336],[29,1519,316],{"className":1520},[131],[29,1522,1524,1559],{"className":1523},[67],[29,1525,1527],{"className":1526},[71],[73,1528,1529],{"xmlns":75},[77,1530,1531,1556],{},[80,1532,1533,1535,1541,1543,1545,1547,1549,1551,1554],{},[83,1534,234],{},[90,1536,1537,1539],{},[83,1538,237],{},[83,1540,1014],{},[509,1542,902],{},[310,1544,1277],{},[509,1546,511],{},[310,1548,1457],{},[509,1550,902],{},[310,1552,1553],{},"38.25",[314,1555,316],{},[110,1557,1558],{"encoding":112},"FL_B = 38.0 + 0.25 = 38.25\\text{ m}",[29,1560,1562,1622,1641,1659],{"className":1561,"ariaHidden":118},[117],[29,1563,1565,1568,1571,1613,1616,1619],{"className":1564},[122],[29,1566],{"className":1567,"style":431},[126],[29,1569,234],{"className":1570,"style":133},[131,132],[29,1572,1574,1577],{"className":1573},[131],[29,1575,237],{"className":1576},[131,132],[29,1578,1580],{"className":1579},[147],[29,1581,1583,1605],{"className":1582},[151,152],[29,1584,1586,1602],{"className":1585},[156],[29,1587,1590],{"className":1588,"style":1589},[160],"height:0.3283em;",[29,1591,1593,1596],{"style":1592},"top:-2.55em;margin-left:0em;margin-right:0.05em;",[29,1594],{"className":1595,"style":169},[168],[29,1597,1599],{"className":1598},[173,174,175,176],[29,1600,1014],{"className":1601,"style":1029},[131,132,176],[29,1603,200],{"className":1604},[199],[29,1606,1608],{"className":1607},[156],[29,1609,1611],{"className":1610,"style":207},[160],[29,1612],{},[29,1614],{"className":1615,"style":931},[536],[29,1617,902],{"className":1618},[935],[29,1620],{"className":1621,"style":931},[536],[29,1623,1625,1629,1632,1635,1638],{"className":1624},[122],[29,1626],{"className":1627,"style":1628},[126],"height:0.7278em;vertical-align:-0.0833em;",[29,1630,1277],{"className":1631},[131],[29,1633],{"className":1634,"style":537},[536],[29,1636,511],{"className":1637},[541],[29,1639],{"className":1640,"style":537},[536],[29,1642,1644,1647,1650,1653,1656],{"className":1643},[122],[29,1645],{"className":1646,"style":329},[126],[29,1648,1457],{"className":1649},[131],[29,1651],{"className":1652,"style":931},[536],[29,1654,902],{"className":1655},[935],[29,1657],{"className":1658,"style":931},[536],[29,1660,1662,1665,1668],{"className":1661},[122],[29,1663],{"className":1664,"style":329},[126],[29,1666,1553],{"className":1667},[131],[29,1669,1671],{"className":1670},[131,336],[29,1672,316],{"className":1673},[131],[215,1675,1676,1754],{},[20,1677,1678,1679,257],{},"Determine Rail Level (",[29,1680,1682,1702],{"className":1681},[67],[29,1683,1685],{"className":1684},[71],[73,1686,1687],{"xmlns":75},[77,1688,1689,1699],{},[80,1690,1691,1693],{},[83,1692,402],{},[90,1694,1695,1697],{},[83,1696,280],{},[83,1698,1014],{},[110,1700,1701],{"encoding":112},"SR_B",[29,1703,1705],{"className":1704,"ariaHidden":118},[117],[29,1706,1708,1711,1714],{"className":1707},[122],[29,1709],{"className":1710,"style":431},[126],[29,1712,402],{"className":1713,"style":435},[131,132],[29,1715,1717,1720],{"className":1716},[131],[29,1718,280],{"className":1719,"style":295},[131,132],[29,1721,1723],{"className":1722},[147],[29,1724,1726,1746],{"className":1725},[151,152],[29,1727,1729,1743],{"className":1728},[156],[29,1730,1732],{"className":1731,"style":1589},[160],[29,1733,1734,1737],{"style":456},[29,1735],{"className":1736,"style":169},[168],[29,1738,1740],{"className":1739},[173,174,175,176],[29,1741,1014],{"className":1742,"style":1029},[131,132,176],[29,1744,200],{"className":1745},[199],[29,1747,1749],{"className":1748},[156],[29,1750,1752],{"className":1751,"style":207},[160],[29,1753],{},[29,1755,1757,1792],{"className":1756},[67],[29,1758,1760],{"className":1759},[71],[73,1761,1762],{"xmlns":75},[77,1763,1764,1789],{},[80,1765,1766,1768,1774,1776,1778,1780,1782,1784,1787],{},[83,1767,402],{},[90,1769,1770,1772],{},[83,1771,280],{},[83,1773,1014],{},[509,1775,902],{},[310,1777,1553],{},[509,1779,511],{},[310,1781,355],{},[509,1783,902],{},[310,1785,1786],{},"41.75",[314,1788,316],{},[110,1790,1791],{"encoding":112},"SR_B = 38.25 + 3.5 = 41.75\\text{ m}",[29,1793,1795,1853,1871,1889],{"className":1794,"ariaHidden":118},[117],[29,1796,1798,1801,1804,1844,1847,1850],{"className":1797},[122],[29,1799],{"className":1800,"style":431},[126],[29,1802,402],{"className":1803,"style":435},[131,132],[29,1805,1807,1810],{"className":1806},[131],[29,1808,280],{"className":1809,"style":295},[131,132],[29,1811,1813],{"className":1812},[147],[29,1814,1816,1836],{"className":1815},[151,152],[29,1817,1819,1833],{"className":1818},[156],[29,1820,1822],{"className":1821,"style":1589},[160],[29,1823,1824,1827],{"style":456},[29,1825],{"className":1826,"style":169},[168],[29,1828,1830],{"className":1829},[173,174,175,176],[29,1831,1014],{"className":1832,"style":1029},[131,132,176],[29,1834,200],{"className":1835},[199],[29,1837,1839],{"className":1838},[156],[29,1840,1842],{"className":1841,"style":207},[160],[29,1843],{},[29,1845],{"className":1846,"style":931},[536],[29,1848,902],{"className":1849},[935],[29,1851],{"className":1852,"style":931},[536],[29,1854,1856,1859,1862,1865,1868],{"className":1855},[122],[29,1857],{"className":1858,"style":1628},[126],[29,1860,1553],{"className":1861},[131],[29,1863],{"className":1864,"style":537},[536],[29,1866,511],{"className":1867},[541],[29,1869],{"className":1870,"style":537},[536],[29,1872,1874,1877,1880,1883,1886],{"className":1873},[122],[29,1875],{"className":1876,"style":329},[126],[29,1878,355],{"className":1879},[131],[29,1881],{"className":1882,"style":931},[536],[29,1884,902],{"className":1885},[935],[29,1887],{"className":1888,"style":931},[536],[29,1890,1892,1895,1898],{"className":1891},[122],[29,1893],{"className":1894,"style":329},[126],[29,1896,1786],{"className":1897},[131],[29,1899,1901],{"className":1900},[131,336],[29,1902,316],{"className":1903},[131],[215,1905,1906,1909,379,2028,32],{},[20,1907,1908],{},"Set Rail above Peg B:",[29,1910,1912,1946],{"className":1911},[67],[29,1913,1915],{"className":1914},[71],[73,1916,1917],{"xmlns":75},[77,1918,1919,1943],{},[80,1920,1921,1924,1926,1928,1930,1933,1936,1938,1941],{},[314,1922,1923],{},"Height",[509,1925,902],{},[310,1927,1786],{},[509,1929,591],{},[310,1931,1932],{},"40.8",[314,1934,1935],{}," (if Peg B level is 40.8)",[509,1937,902],{},[310,1939,1940],{},"0.95",[314,1942,316],{},[110,1944,1945],{"encoding":112},"\\text{Height} = 41.75 - 40.8 \\text{ (if Peg B level is 40.8)} = 0.95\\text{ m}",[29,1947,1949,1971,1989,2013],{"className":1948,"ariaHidden":118},[117],[29,1950,1952,1956,1962,1965,1968],{"className":1951},[122],[29,1953],{"className":1954,"style":1955},[126],"height:0.8889em;vertical-align:-0.1944em;",[29,1957,1959],{"className":1958},[131,336],[29,1960,1923],{"className":1961},[131],[29,1963],{"className":1964,"style":931},[536],[29,1966,902],{"className":1967},[935],[29,1969],{"className":1970,"style":931},[536],[29,1972,1974,1977,1980,1983,1986],{"className":1973},[122],[29,1975],{"className":1976,"style":1628},[126],[29,1978,1786],{"className":1979},[131],[29,1981],{"className":1982,"style":537},[536],[29,1984,591],{"className":1985},[541],[29,1987],{"className":1988,"style":537},[536],[29,1990,1992,1995,1998,2004,2007,2010],{"className":1991},[122],[29,1993],{"className":1994,"style":945},[126],[29,1996,1932],{"className":1997},[131],[29,1999,2001],{"className":2000},[131,336],[29,2002,1935],{"className":2003},[131],[29,2005],{"className":2006,"style":931},[536],[29,2008,902],{"className":2009},[935],[29,2011],{"className":2012,"style":931},[536],[29,2014,2016,2019,2022],{"className":2015},[122],[29,2017],{"className":2018,"style":329},[126],[29,2020,1940],{"className":2021},[131],[29,2023,2025],{"className":2024},[131,336],[29,2026,316],{"className":2027},[131],[29,2029,382],{},[11,2031,2033],{"id":2032},"practical-tips","Practical Tips",[1178,2035,2036,2045,2054],{},[215,2037,2038,2041,2042,32],{},[20,2039,2040],{},"Color Coding:"," If using different lengths of boning rods (e.g., one for excavation and one for pipe invert), paint the rod and its corresponding sight rail the same color to avoid confusion ",[29,2043,2044],{},"16",[215,2046,2047,2050,2051,32],{},[20,2048,2049],{},"Double Rails:"," On steep slopes, use \"Double Sight Rails\" with different rod lengths to maintain a clear line of sight ",[29,2052,2053],{},"15, 17",[215,2055,2056,2059,2060,32],{},[20,2057,2058],{},"Offsetting for Machinery:"," Ensure rails are offset far enough so the excavator can pass between them without knocking them over ",[29,2061,2044],{},[11,2063,2065],{"id":2064},"common-mistakes","Common Mistakes",[1178,2067,2068,2078],{},[215,2069,2070,2073,2074,2077],{},[20,2071,2072],{},"Assuming Board Thickness:"," Always level the ",[20,2075,2076],{},"top edge"," of the sight rail. If you level the center of the board, the thickness of the timber introduces a systematic error.",[215,2079,2080,2083,2084,32],{},[20,2081,2082],{},"Rod Tilt:"," The boning rod must be held perfectly vertical. Use a circular bubble on the rod to ensure accuracy ",[29,2085,2086],{},"17",[11,2088,2090],{"id":2089},"faq","FAQ",[2092,2093,2094,2103,2111],"accordion",{},[2095,2096,2098],"accordion-item",{"label":2097},"Can I use a laser instead?",[16,2099,2100,2101,32],{},"Yes, a laser beam set to the design gradient can replace the visual line between rails. The rod then uses a photo-electric target to detect the beam ",[29,2102,2086],{},[2095,2104,2106],{"label":2105},"What is a 'Traveller'?",[16,2107,2108,2109,32],{},"A traveller is essentially a long boning rod used specifically to 'travel' along the trench to check the grade at any intermediate point ",[29,2110,382],{},[2095,2112,2114],{"label":2113},"How do I control the pipe invert?",[16,2115,2116,2117,32],{},"Calculate the bedding thickness and add a second cross-head to the boning rod at that specific distance to control the actual pipe laying ",[29,2118,2119],{},"15, 16",[11,2121,2123],{"id":2122},"conclusion","Conclusion",[16,2125,2126,2127,2182],{},"Sight rails and boning rods represent the perfect marriage of simple geometry and practical engineering. By following the ",[29,2128,2130,2149],{"className":2129},[67],[29,2131,2133],{"className":2132},[71],[73,2134,2135],{"xmlns":75},[77,2136,2137,2147],{},[80,2138,2139,2141,2143,2145],{},[83,2140,234],{},[83,2142,237],{},[509,2144,511],{},[83,2146,280],{},[110,2148,516],{"encoding":112},[29,2150,2152,2173],{"className":2151,"ariaHidden":118},[117],[29,2153,2155,2158,2161,2164,2167,2170],{"className":2154},[122],[29,2156],{"className":2157,"style":526},[126],[29,2159,234],{"className":2160,"style":133},[131,132],[29,2162,237],{"className":2163},[131,132],[29,2165],{"className":2166,"style":537},[536],[29,2168,511],{"className":2169},[541],[29,2171],{"className":2172,"style":537},[536],[29,2174,2176,2179],{"className":2175},[122],[29,2177],{"className":2178,"style":250},[126],[29,2180,280],{"className":2181,"style":295},[131,132]," logic, you provide site crews with a reliable, visual reference that ensures every meter of drainage is laid to perfection.",[11,2184,2186],{"id":2185},"references","References",[16,2188,2189,2190,2194],{},"Schofield, W. (2001). ",[2191,2192,2193],"em",{},"Engineering Surveying",". 5th ed. 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