Page 1 of 5 Fundamentals for Cracking Verification of Reinforced Concrete Structures Pier Giorgio Debernardi and Maurizio Taliano* Politecnico di Torino, Italy Research Article Copyright © All rights are reserved by Pier Maurizio Taliano ISSN: 2643-6876 DOI: 10.33552/CTCSE.2021.07.000654 Current Trends in Civil & Structural Engineering This work is licensed under Creative Commons Attribution 4.0 License CTCSE.MS.ID.000654. Abstract A mathematical model, named as general method, has been set up to study the cracking behaviour of a concrete tie reinforced by ordinary bars, subjected to a monotonic load. The analysis is performed considering both the crack formation stage and the stabilized cracking stage. In particular, secondary cracks occur in the stabilized cracking stage, modifying the distribution of bond stress along the transmission length. As in the stabilized cracking stage the solution of the general method requires to carry out an iterative numerical procedure, for design purposes the maximum crack width can be determined through a simplified method that allows the main aspects of the structural behaviour to be taken into account. *Corresponding author: Maurizio Taliano, Department of Structural, Geotechnical and Building Engineering, Politecnico di Torino, Italy. Received Date: March 03, 2021 Published Date: April 08, 2021 Introduction Cracking in concrete structures has to be considered normal and, in general, it does not indicate a construction defect or dan- ger when it remains within limits established by standards or contracts [1,2]. Cracks, that can already occur in fresh concrete, are due to either direct loading or restraint or imposed deforma- tions and appear when the tensile strength of concrete is reached. Two types of cracks can be observed in structural members, that means primary cracks, that propagate inside the concrete reaching the concrete surface, and secondary cracks or Goto cracks [3], that develop around the reinforcement bars remaining mostly inside the concrete. Limiting the maximum crack width is aimed at avoid- ing to impair the aesthetic aspects, also in order to not generating alarmism among people, and preserving the structural durability or the sealing capacity in case of tanks or retaining structures. To this regard appropriate limits of the crack width are introduced for the various service conditions, generally not exceeding 0.4 mm. In the following, the case of cracking due to loading is examined, as it is the most frequent case, and a mathematical modelling is proposed for the calculation of the maximum crack width in service condi- tions [4,5]. Stages of the Cracking Behaviour and Calculation Assumptions Primary cracks occur in the tension chord of the structural members, where the steel reinforcement is located to control their spacing and width. For the sake of modelling, the cracking analysis of the tension chord is usually performed considering an ideal RC tie with an effective area, A c,ef For instance, the height of the effective area of concrete can be assumed equal to 2.5 · (h − d), being h and d the height and the depth of the structural member, respectively. Here, the concrete tie is assumed to be reinforced by n s bars, with diameter ϕ s and total area A s , and subjected to an increasing axial force F s . Three stages can be considered, that means: 1. The uncracked stage, where the tensile strength of the con- crete, f ct , is not reached and both concrete and steel present a linear elastic behaviour. 2. The crack formation stage, that starts when in a certain section the concrete tensile strength is overcome, and the first crack occurs. In this stage, when the axial force F s increases, further cracks can form.