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1" - r - <br />.'r :.a <br />;3 <br />S' Zp 30 $ <br />7 <br />P <br />CURVE TABLES <br />—_5-T71- <br />zs 3 Published by KEUFFEL & ESSER CO. <br />HOW TO USE CURVE TABLES <br />Table 1. contains Tangents and Externals to a 1' curve. Tan. and <br />Ext to an othe- rad; b f d 1 h b d' 'A: th T <br />y _ us may a oun near y enoug , y ivI ng a an. <br />or Ext. opposite the given Central Angle by the given degree of curve. <br />To find Deg., of Curve, having the Central Angle and Tangent: <br />37 9 Divide Tan. opposite the given Central Angle by the given Tangent. <br />To find Deg. of Curve, having the Central Angle and External: <br />Divide Ext. opposite the given Central Angle by the given External. <br />To find Nat. Tan. and Nat. Ex. Sec. for any -angle by Table L: Tan. <br />_ ? 1 or Ext. of twice the given angle divided by the radius of a 1° curve will <br />be the Nat. Tan. or Nat. Ex. Sec. <br />-r� - - EXAMPLE <br />"°� �f Wanted a Curve with an Ext. -of about 1.2 ft. Angle <br />/0 - of Intersection or L' P.1=231 20' to the R. at Station <br />542+72. <br />! $ <br />� xt. in Tab. I opposite 23° 20'= 120.87 <br />-)N:120.87-12=10.07. Say a-10* Curve. <br />Tan, it.. Tab. I opp. 23° 20'=1183.1 <br />-1183.1 <br />Correction for A. 23° 20' for a 10° Cur. =0.16 <br />. 118.31 +0.16 =118.47= corre&ed Tangent. <br />L= <br />(if corrected Extis required find in same way) <br />- <br />t <br />' 00 5/1 <br />Ang.23°20'=23.33°=10=2.3333=L. C. <br />(v' <br />2° 19i'=def. for sta. 542 <br />l: P. =sta. 542- 72 <br />00 G <br />4° 491' _• +50 <br />Tan. = 1 . 18.47 <br />7° 191'= u u 543 <br />9° 491' — ° u x-50 <br />B. C.=sta. 541 53.53 <br />11°401= " rr 543+ <br />L.C.= 2 .33.33 <br />86.86 <br />E. C. = Sta. 543+86.86 <br />100=53.53=46.47X3'(def. for 1 ft. of 10° Cur.) =139.41'=. <br />- 2° 19"=def, for sta. 542. <br />Def. for 50 ft. =2° 30' for a 10° Curve. <br />Def. for 36.86 ft. =1° 501' for a 10° Curve. <br />l <br />- <br />�*e <br />x, <br />r � LP,An9.23.20• <br />- <br />