عملكرد روسازي بتني ساده درزدار با داول هاي صفحه اي داراي ورق سخت كننده

In jointed plain concrete pavements (JPCPs), joint performance plays a crucial role in the structural integrity of the pavement under traffic-induced displacements and stresses. Dowels are installed at joints to prevent faulting and transfer a portion of the load from the loaded concrete slab to the unloaded adjacent slab across the joint. The performance of joints under loading is eva‎luated by analyzing structural responses of the joint to assess stresses and determine the joint health by estimating the load transfer efficiency (LTE). The type of dowels employed at the joint significantly influences joint behavior. Conventional dowels are typically circular, but due to their looseness under heavy traffic loads, the use of plate dowels has been proposed. However, plate dowels exhibit low bending stiffness, resulting in reduced joint performance. The development of a dowel type that maintains joint performance while preventing loosening is essential for improving pavement performance, particularly under heavy traffic loads. This study introduces a novel dowel type called cross dowels. Cross dowels are essentially plate dowels reinforced with two stiffening plates. The study investigates the performance of JPCPs with different dowel types, including circular, plate, and cross dowels. Additionally, the influence of concrete slab thickness and modulus of subgrade reaction on joint behavior is eva‎luated. The study employs three-dimensional finite element modeling using the ABAQUS software. Each model consists of two concrete slabs resting on the base layer located on the subgrade, with each model representing various concrete thickness and soil stiffness conditions for joints with circular, plate, and cross dowels. An eight-ton static pressure is applied at the joint edge in the corner of the concrete slab. The results obtained from the analysis of the models demonstrate that cross dowels exhibit higher LTE than joints with circular or plate dowels. Plate dowels exhibit the poorest joint LTE. Moreover, the load is primarily transferred by the dowels through their shear action, and the transferred load for cross dowels is higher than that for plate and circular dowels. Increasing the concrete slab thickness reduces the stresses in the pavement and subgrade layer. Increasing the subgrade stiffness reduces the stresses in the concrete slab and dowels while increasing the stresses in the soil. The presence of dowels at joints is crucial for ensuring joint functionality, particularly for concrete slabs with less thickness and pavements on weak subgrades. Cross dowels outperform circular and plate dowels in joint performance by enhancing joint efficiency and reducing contact stresses. Further eva‎luation and understanding of the behavior of these dowels are essential for improving the design and implementation of pavement joints.

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