page_title: Arching or compressive membrane action in reinforced concrete slabs
section_title: Background
hierarchical_section_title: Arching or compressive membrane action in reinforced concrete slabs / Background
caption_attribution_description: English: Arching action (CMA) strength enhancement in laterally restrained slab strip
context_page_description: Arching or compressive membrane action in reinforced concrete slabs occurs as a result of the great difference between the tensile and compressive strength of concrete. Cracking of the concrete causes a migration of the neutral axis which is accompanied by in-plane expansion of the slab at its boundaries. If this natural tendency to expand is restrained, the development of arching action enhances the strength of the slab.
  The term arching action is normally used to describe the arching phenomenon in one-way spanning slabs and compressive membrane action is normally used to describe the arching phenomenon in two-way spanning slabs.
context_section_description: The strength enhancing effects of arching action in reinforced concrete floors were first recognised near the beginning of last century. However, it was not until the full scale destructive load tests by Ockleston on the Old Dental Hospital in Johannesburg that the extent of strength enhancement caused by arching action was really appreciated.  In these tests, collapse loads of between 3 and 4 times those predicted by yield-line theory were obtained.
caption: Arching action (CMA) strength enhancement in laterally restrained slab strip
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