Continuously Reinforced Concrete Pavement

1. Continuously Reinforced Concrete Pavement Pavement Engineering M. Kharabsheh

2. Pavement Engineering M. Kharabsheh

3. Factors that must be Considered by Pavement Engineer. Must Know • Short Slabs can be designed and load transfer is provided by Aggregate Interlock (Contraction Joint) • The crack or contraction joint can be tied with Tie Bars of distributed steel to prevent the crack or joint from opening • Movement at joints can be permitted (Expansion Joints) and Dowel Bars are placed at the Joints to provide load transfer. Pavement Engineering M. Kharabsheh

4. Construction Joints with Tie Bars Pavement Engineering M. Kharabsheh

5. Contraction joint showing saw cut depth Pavement Engineering M. Kharabsheh

6. Aggregate Interlock (Contraction Joint) Pavement Engineering M. Kharabsheh

7. (Contraction Joint) Pavement Engineering M. Kharabsheh

8. (Contraction Joint) Pavement Engineering M. Kharabsheh

9. (Expasion Joint) Pavement Engineering M. Kharabsheh

10. Dowel Bars Storage Pavement Engineering M. Kharabsheh

11. Dowel Bars Construction Pavement Engineering M. Kharabsheh

12. Dowel Group Action • When traffic loads are applied at a joint, a portion of this load is transferred through the dowel bar into the next slab (this portion should be 50% for perfect load transfer) • The dowel bar immediately under the applied load bears a major portion of the load with other dowels assuming progressively lesser amount. Pavement Engineering M. Kharabsheh

13. Dowel Group Action • Maximum negative moment occurs at a distance 1.8L from the load. • The dowel bar immediately under the applied load carries full capacity (one full unit) and the portion of each dowel decrease to reach zero at a distance of 1.8L. • The corner dowel is the critical one for the edge load. Pavement Engineering M. Kharabsheh

14. Example • Load is 9000lb on each wheel • Assume 50% load transfer • Thickness= 10’ and Subgrade reaction = 50pci • Radius of relative Stiffness l = 51.1’ (from table 3.1 page 84) Pavement Engineering M. Kharabsheh

15. Example • X1 = 1 • 1/92 = x2/(92-12) x2 = 0.87 • Effective Dowels group for load at A = S xi = 1+.87+.74+.61+.48+.35+.22+.08 = 4.35 • Total load carried by dowel At point A = load from wheel At A plus load from wheel at Point B Total load at A = 4500/(4.35*1) + 4500/(7.32*0.22) = 1035+135= 1170 lb Pavement Engineering M. Kharabsheh

16. Example on Bearing Stress by Dowel on Concrete Pavement Engineering M. Kharabsheh

17. Pavement Engineering M. Kharabsheh

18. Pavement Engineering M. Kharabsheh