POETLAND CEMENT CONCRETE ROADS. 



19 



Figure 5. As the offset from the tangent to the inner circular curve 

 in this case will be increased by the amount of widening required, 

 the length of the transition to the inner edge of the pavement will 

 always ,be longer than the transition used on the outer edge of the 

 pavement. The use of transition curves will materially increase the 

 field operations of staking out the work, but it is believed their use 

 is desirable on curves of from 200 to 1,000 foot radius. 



Edge of Standard Section 



Tapered Portion of Pavement 

 -Center Line of Standard Section- 



R= Radius of Center Line of Standard Section of Pavement 



PC.= Point of Curve. 



PT= Point of Tangent 



W= Width of Standard Section of Pavement 



A = Additional Width of Pavement on Account of Curve. 



100 Feet = Length of Taper. 



NOTE:- The Taper will not strictly be Tangent to the Widened 

 Portion of the Curve at the PC. The Point of Tangency is 



so NEAR the PC. however, THAT A SLIGHT SHIFTING OF THE 



Forms at this Point during the Setting will connect the 

 Taper with the Curve without any Noticeable Break. 

 In no case will the Forms at the PC. have to be moved 

 MORE than .15 Foot, 



Fig. 4. — A simple method of widening curves. 

 Table of curve widening. 





Additional widtli of pave- 





Additional widtli of pave- 



Radius 



ment required 



for — 



Radius 



ment required for — • 



of 

 center 







of 

 center 



















line 



16-foot 



18-foot 



20-foot 



line 



16-foot 



18-foot 



20-foot 



curve. 



pave- 



pave- 



pave- 



curve. 



pave- 



pave- 



pave- 





ment. 



ment. 



ment. 





ment. 



ment. 



ment. 



Feet. 



Feet. 



Feet. 



Feet. 



Feet. 



Feet. 



Feet. 



Feet. 



30 



8.0 



11.0 



14.0 



125 



3.5 



4.0 



4.0 



40 



6.0 



8.0 



9.6 



150 



3.5 



3.5 



3.5 



50 



5.5 



6.5 



7.5 



175 



3.0 



3.0 



3.0 



60 



5.0 



5.5 



6.5 



200 



3.0 



3.0 



3 



70 



4.5 



5.0 



5.5 



250 



3.0 



3.0 



2.5 



80 



4.0 



4.5 



5.0 



300 



3.0 



2.5 



2.5 



90 



4.0 



4.5 



4.5 



400 



3.0 



2.5 



2.0 



100 



4.0 



4.0 



4.5 



500 



2.5 



2.5 



2.0 



