Evaluation of equivalent delamination driving coefficient in bonded concrete overlays

This study investigates failure due to interfacial delamination in a bonded concrete overlay system comprising Polymer Modifies Roller Compacted Concrete (PMRCC) overlay and substrate Ordinary Portland Concrete (OPC). Optimum overlay mix was designed using Composite Desirability Analysis (CDA). Intrinsic complex stresses along the plane of the interface resulting from differential length change and elastic mismatched properties between the two bonded layers were investigated. Distinct delamination cases involving variable structural scales were investigated using both laboratory determined fracture parameters and ANSYS zero-thickness Interface Cohesive Zone Model (ICZM) concept. The FEA results showed that the restraint capacity of the interface varies as a function of overlay structural scale and its associated mismatched elastic parameters

Numerical investigation of tension reinforcement lap length of eurocode 2 using a four-point beam loading system

© 2019 Latin American Journal of Solids and Structures. All rights reserved. This report presents a computational research on Eurocode 2 (EC2) tension lap lengths (lo) design in a normally reinforced concrete beam, using ANSYS Workbench simulation software program by simulating a laboratory 4-point beam loading test system under static loading(discrete model approach). A typical 4-point laboratory setup loading system was modelled using an innovative and sustainable Finite Element Analysis (FEA) approach. In order to investigate the EC2 tension lap lengths (lo) design recommendation, a total of 100 analysis cases of lap lengths were considered for different reinforcement bar diameters of 10mm, 12mm, 16mm, 20mm and 25mm. The study has considered beam failure types, effects of failure load on the various lap length reduction cases and effects of steel reinforcement bar size changes on the design lap lengths. The analysis of results revealed that the yield strength of steel (fyk), diameter of tension reinforcement bar, (db), tensile strength of concrete (fctd) and concrete cover (cd) are the main parameters for a tension lap length design according to EC2. While a linear relationship exists between tension steel reinforcement bar sizes (db) and the obtained lap lengths (lo). The study reveals a potential use of 15% and 20% reduction in lap length (lo) for tension steel reinforcement bar sizes of 10mm, 16mm and 12mm and 20mm in comparison with the recommended design lap length of EC2. It was concluded that EC2 tension lap length design recommendation is conservative