Anomalías en flexión-compresión y formas de evitarlas

Anomalies in the bending and compression theory and how to avoid them

Some anomalies are reported in the Bending and Compression Theory, i.e. in the theory of analysis of Reinforced Concrete cross-sections submitted to bending and compression. In certain circumstances, some of which are frequent in practice, if reinforcement is added to a cross-section whose resistance is sufficient in accordance with the theory, a decrease of resistance results which can lead to failure. This effect has been called the harmful reinforcement paradox. The ordinary procedure for cross-section analysis and design implicitly erequires the convexity of the interaction diagram (or surface). However, in some cases, including rectangular cross-sections with normal reinforcement, small concavities are reported to appear in the interaction diagram. These anomalies hace limited practical interest. However, tey are considered important from the theoretical point of view, as they show a lack of cogerence in the basic assumptions lying under the bending and compression theory. Some suggestions are preseted to modify these basic assumptions to that these lack of coherence can be avoided.