Thesis (M.Sc.) - Cairo University - Faculty of Engineering - Department of Civil Engineering

The shear strength of joints is a very important issue in the design of prestressed concrete segmental systems. In this research, finite element models of these joints under different parameters have been studied. The parameters considered in the thesis include: (i) types of joints, (ii) number of shear keys, (iii) confining pressure, (iv) concrete strength, (v) shear transfer coefficient for dry joints, and (vi) friction coefficient. Three types of joints were used: Dry joints with shear keys and without any filling materials, epoxy joints having a thin layer of epoxy between segments, and monolithic joints with full bond. Single keyed, two keyed, and three keyed joints were considered in this study subjected to three levels of confining pressure (1, 2, and 3 MPa), concrete strength of 40, 50, and 60 MPa, with six values of friction coefficient for dry joints ranging from 0.1 to 1.0, and eight models with a variable shear transfer coefficient at single keyed joints. The FEM model was first calibrated and validated with the experimental results for single-keyed joints described in the literature. Then, Nonlinear Materials analysis was carried out for different combinations of the above mentioned parameters. In total thirty five FEM models were developed. The results show shear behavior, shear capacity, crack patterns, and how the loads are transferred from one segment to the other. Among the main conclusions: The shear capacity increases with the increase of either the confining pressure or the concrete strength. The shear capacity of joints increase as the number of keys increase. Coefficient of friction between two segments plays role in increasing the capacity of the shear keys

Issued also as CD