FEM modelling of unbonded post-tensioned segmental beams with dry joints

This work presents a finite element method (FEM) study of the structural behavior of segmental concrete structures with external pre-stressing, focusing on the response of these structures under combined shear and flexure. Some FEM models have been validated using experimental shear tests conducted on 7 m long segmental beams. Three types of models with different levels of complexity are presented. The first one attempts to reproduce the behaviour of the beams modelling the joint with its real geometry. The second model refines the previous one, introducing the cracking observed in the experimental tests by means of a discrete crack. The third model evaluates the possibility of reproducing the experimental test results using a flat joint model, simplifying the modelling by not reproducing the interlocking geometry of the keys.Since this work aims to shed light on the shear flow mechanism in these types of structures, a theoretical study of the shear transference is carried out, analyzing the stress flow that develops in the web of these types of structures after the joint opens. The arch effect is identified as the structural response mechanism that carries the actuating vertical loads. Interesting conclusions are also extracted from the study regarding the reinforcement of these structures.