Theory and design of Structures

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☑️ wind load calculation based on ES EN 1991-4-2105 The procedure to determine the internal and external wind pressure is shown in a brief manner in the pdf below.

ሀገራችን የዮኒቨርስቲ ዘረኝነቷን ልታቆም ይገባል፡፡ ሰው ከግል ዮኒቨርስቲ ስለተመረቀ ብቻ ትምህርት እማይችል እና ውጤት ተለግሶት የወጣ ተደርጎ መታየት የለበትም፡፡ ማንም ሰው የድካሙን ልክ እንጂ የተማረበትን ቦታ ቅርፅ ይዞ አይወጣም፤ ከግልም ከመንግስትም ግሬድ ብቻ የያዘ አለና፡፡

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☑️ Shear design Example based on ES EN 1992-1-1:2015 The pdf provided gives an example on shear design based on the new Ethiopian code. @theoryanddesignofstructures ⬇️

☑️ES EN RELATED POINTS As usual points important to design beams for shear based on ES EN 1992-1-1:2015 are discussed in the pdf below. @theoryanddesignofstructures ⬇️

👆👆👆 ✳️Shear failure vedio. ✳️Shows how catastrophic the failure is. @theoryanddesignofstructures

ѕнєαя "It is important to realize that shear analysis and design are not really concerned with shear as such. The shear in most beams are far below the direct shear strength of concrete. The real concern is with diagonal tension stress , resulting from the combination of shear stress and longitudinal stress" 📚 From design of concrete structures 14th edition, Nilsson et. al. @theoryanddesignofstructures

An important point on shear design ⬇️

👉Design shear is taken at 'd' distance from the face of support because diagonal tension cracks due to shear occur some distance away from the support and this picture is an evidence.

✔️ The maximum shear force is at the support for a predominantly uniformly distributed load. Yet, the design shear force is taken at 'd' distance from the face of support. The reason is shown in the picture below @theoryanddesignofstructures ⬇️

Diagonal tension cracks propagate from top to bottom and the beam finally splits. Author:- Sigurdur Runar Birgisson( REYKJAVIK UNIVERSITY)

Formation of diagonal tension cracks. Author:- Sigurdur Runar Birgisson( REYKJAVIK UNIVERSITY)

Shear failure pictures ⬇️

ѕнєαя ƒαιℓυяє 👉shear failure is sudden and brittle failure. The failure is with diagonal cracks occuring some distance from the face of support. 👉on any given section shear and flexure occur at the same time( except point with either shear or moment is zero). The interaction of the two stresses, if the principle of stress transformation is followed, develop tension and shear at an angle different from 0 or 90°. 👉The diagonal tension resulting from interaction of shear and flexure is responsible for shear failure. 👉beams without shear reinforcement faile in one of the five modes: ☑️diagonal tension ☑️shear compression ☑️shear tension ☑️web crushing and ☑️arch rib failure. 👉The failure mode likely to occur depends on: ☑️moment to shear ratio( M/V), ☑️ type of loading(concentrated or distributed) ☑️beam cross section. 👉 concrete without shear reinforcement resists shear by the contribution of: ☑️concrete uncracked section, ☑️aggregate interlock and ☑️due to dowel action of longitudinal reinforcement. @theoryanddesignofstructures