This paper presents an overview of the theory behind flexural strength of reinforced concrete beams and design for different failure modes according to ACI 318-19. Focus is given to concepts that are appropriate for an undergraduate reinforced concrete course. The technical content critical to this topic is summarized and pedagogical techniques for presenting this content effectively are described. Examples of applying these pedagogical techniques in the classroom are provided with estimates of required preparation and classroom time. These examples include several models and illustrations that can be used in the classroom and a sample large-scale laboratory exercise illustrating the different possible flexural failure modes. Finally, lessons learned from the authors over many years of instruction at multiple institutions are provided regarding techniques that have worked well when teaching this topic in a typical undergraduate reinforced concrete course.

This paper presents an overview of shear analysis and design based on the ACI 318-19 Building Code Requirements for Structural Concrete as it relates to an introductory reinforced concrete course. The important content related to this topic is summarized and several effective active learning strategies and pedagogical resources are presented to augment and enhance student learning for this challenging topic. The description of each active learning activity also includes a discussion of the underlying pedagogical theory, an estimate of preparation and implementation time, and recommendations for implementation. The paper also highlights lessons learned from the authors based on observations from several years of instruction.

Post-earthquake evidence shows that shear failure in non-ductile detailed columns is a major source of structural collapse and earthquake deaths. Nonlinear continuum finite element (FE) models were constructed and calibrated to experimental tests for nine columns sustaining shear and axial degradation during cyclic loading. The primary objective of this study was to develop FE guidelines for simulating the lateral cyclic behavior of concrete columns sustaining shear degradation and axial collapse, such that wider parametric studies can be conducted numerically to improve the accuracy of assessment methodologies for such critical columns. Selected columns covered a practical range of axial loads, shear stresses, transverse reinforcement ratios, longitudinal reinforcement ratios, and shear span to depth ratios. The crack width, the damage in concrete and reinforcement, the drift at axial and lateral collapse, and the shear capacity of columns are compared with experimental results and standards equations from ASCE 41-17 and the ACI 318-19. It is observed that material model parameters recommended in this study are delivering relatively high accuracy for columns with span-to-depth ratios above 2 up to the axial collapse, and for columns with span-to-depth ratios below 1 up to the lateral failure.

Experimental tests have been performed on interior post-tensioned (PT) slab-column (SC) connections over the past several decades. This paper presents a comprehensive database of 92 such tests performed on interior PT SC connections without shear reinforcement under direct shear. The data was then analyzed to compare the accuracy of the punching shear provisions of ACI 318-19, Eurocode 2 (2004), and CSA A23-19. Several key parameters were evaluated for the PT SC specimens including the concrete compressive strength, specimen geometry, bonded flexural reinforcement ratio, and minimum area of bonded flexural reinforcement; and their influence on the two-way shear strength of these connections was studied. Recommendations are made for possible modifications to the provisions of ACI 318-19 including the limit on the value of the concrete compressive strength f_c^'. Areas for further study, including size effect and bonded flexural reinforcement requirements, are highlighted.

While the punching shear behavior of centrically loaded footings has been investigated in the past, the influence of unbalanced moments has remained almost uninvestigated for footings. Nevertheless, unbalanced moments are also transferred into the column by shear stresses requiring consideration in punching shear design. Here, design approaches often use coefficients to increase the load on action side or to decrease the resistance. To fill the gap in test data necessary for validation of design approaches, tests of four centrically and fourteen eccentrically loaded footings without shear reinforcement were conducted. Here, innovative measurement techniques were used to determine the development of the compression ring at the column-footing connection. While the constriction of the concrete compression zone due to the multiaxial load transfer leads to the formation of a circumferential compression ring with multiaxial concrete strains for centrally loaded slabs, which enhances the punching shear resistance compared to one-way shear, this compression ring only develops to a reduced extent with increasing load eccentricity. Based on the test results, a new proposal for consideration of unbalanced moments is proposed and compared to existing design approaches according to ACI 318-19, Eurocode 2 and the stable version of new Eurocode 2.