Effects of Hinged dowel system on the performance of concrete pavement joints

Concrete joint failure is a major distress mode in rigid pavements. Improving the joint performance in concrete pavements could yield substantial savings in terms of reduced maintenance and rehabilitation costs. The newly developed Hinged Dowel System (HDS) is a means for transferring loads across the concrete pavement joints. The HDS was patented as a new invention by the United States Patent and Trademark Office, and it is envisioned that it could significantly reduce the potential for joint failure in concrete pavements. The HDS assembly comprisesa number of dowel bars and a collective hinge provided at the mid-length of the dowel bars. A finite element analysis showed that the application of HDS reduces the shear stress in concrete pavement joints by approximately 15% when compared to the conventional dowel bars. This amount of reduction in shear stress could translate into a significant reduction in shear-induced failures in concrete pavements. The HDS includes mechanisms which would allow a horizontal slip condition for the dowel bars imbedded in concrete. Moreover, these mechanisms eliminate the punching stress at the dowel tip, which is often induced by thermal expansion of the concrete slabs. The hinge in the HDS gives the concrete slab joints a degree of flexibility to reduce the stresses caused by daily curling and warping of slabs, and seasonal expansion and contraction. In addition to installation in new concrete pavements, the HDS could be utilized in retrofit of old concrete pavements. Finally, the HDS eliminates most construction-relatedissues associated with the installation of dowel bars, such as dowel bar misalignment and full-depth joint cut.