  This study examines the performance of traditional round dowels in concrete
floors and attempts to optimize the design of dowels through Finite Element
(FE) analysis. A new type of Double-Tapered Round (DTR) dowels is proposed, and
the performance of DTR dowels is compared to that of traditional cylindrical
dowels. Linear Elastic (LE) analysis are performed in Abaqus (v-6.11) order to
identify the optimized geometry of DTR dowels that would achieve (1) highest
load transfer across adjacent slabs through shear action, and (2) lowest
bearing stresses on the concrete. LE analyses are complemented by nonlinear FE
analysis. The Riks method available in Abaqus/Standard, coupled with the
Concrete Damaged Plasticity (CDP) model is used to simulate the degradation of
concrete surrounding both DTR the traditional cylindrical dowels. Results
obtained show that the use of DTR dowels can reduce bearing stresses at the
face of the joint by as much 2.2 times as compared to traditional cylindrical
dowels. While adequate load-transfer is a crucial part for the proper
performance pavement structures, the load-transfer capacity of DTR dowels was
more effective over cylindrical dowels by as far as 116%. In the inelastic
range, even after significant concrete degradation and steel yielding, DTR
dowels maintained a higher load-transfer capacity than traditional cylindrical
dowels, and also presented lower amounts of differential deflections across
concrete floors. Finally, damage in the concrete matrix below the dowel was
relatively more confined for the case of DTR dowels, as compared to traditional
cylindrical dowels.
