الفهرس 
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Abstract
As a result of increasing traffic volumes and the aging of transportation infrastructure, the need for rapid construction increases for new bridges. One of the techniques used in construction to meet that requirement is prefabrication of bridge elements, which are often casted in parallel near the site in the yard or in precast factories for saving time, and then they are transferred to the site for assembly in place. So, it reduces transportation network obstruction, construction time, and field labor requirements. Precast columns to base pocket connections type are studied in this research. Due to the lack of experimental, numerical, and analytical studies for pocket connections, an extensive experimental program has been previously conducted at Ain Shams University for different columns and pocket connection types. In this research extensive numerical FE modeling is carried out for some previously tested specimens to obtain validated contact and material modeling parameters for different connection types. The specimens included: three circular pocket connections with smooth interface surface, three circular pocket connections with rough interface surface and six square pocket connections with smooth interface surface. Contact element was defined to transfer loads between precast column, grout and base bodies. Definition of contact element depends on two main parameters, the normal contact stiffness (FKN) for normal behavior and the coefficient of friction (µ) for tangential behavior. It was found that using FKN value of 1.00 and a coefficient of friction value of 0.70 best simulate the behavior of circular specimens with rough interface surface. Using FKN value of 1.00 and a coefficient of friction value of 0.50 best simulate the behavior of circular specimens with smooth interface surface. Based on these results, a parametric study was conducted for circular partially embedded type. The parametric study enables the extension of the previously conducted experimental program by varying some parameters such as embedded length to column diameter ratio, interface surface and column size. Finally, based on these results design recommendations were proposed for partially embedded circular connections with rough and smooth interface surface.
Keywords: Pocket connection; Precast column; foundation; Nonlinear finite element models