I was standing on a thin (to me) concrete platform and remarked to an accompanying friend, "I just cant see how this is strong." I can see how it's strong now. Good job, boffins.
This looks like a flexural failure first... perhaps you should have designed the beam without stirrups and cross steel if you wanted shear failure first... Down size the steel or change dimensions of beam... or even bring load point in closer... Just looks like flexural failure first and of course shear may happen afterwards or it can just fail at the flexural failure and no shear can be clearly shown...
When concrete breaks do the rocks usually shear with the crack or just pull out.....looking at the bridge in florida i have never seen rocks shear so clean..like the were using soft rocks..??
Good question. I would say that initially you're seeing flexure cracks, they start on the bottom of the beam where the bending stress produces tension. The big crack that forms and ultimately causes failure looks like a shear crack to me. It's at an angle of tensile stress created from the transformation of shear stress (i.e., Mohr's Circle).
WisconsinEngineerUWP Thanks! Is there a way to determine what causes the beam to fail in shear rather that tension? I'm guessing its mostly based on lack or excessive reinforcement of either one right?
Ed Cadiri In this case we purposefully under-reinforced for shear and then placed the load so that it would generate a high shear force, but relatively low bending stress. In general, in determining whether it's a shear or moment failure the location of the failure is important (e.g., near support) and also the orientation of the crack (shear cracks are typically at about 45 degrees).
+Mhamad Riyad Thanks! so it's mostly related to the location of the failure and thanks +WisconsinEngineerUWP for mentioning a similar explanation above.
there is no shear or flexural failure both are principal stress failure in tension where principal stresses are in angle close to supports. Crack is always perpendicular to tensile stress. In short beams support region is problematic in long beams mid cross section is problematic. I am just typing this because people sometimes dont realize its more about principal stress trajectories than strictly trying to isolate shear and flex
I was standing on a thin (to me) concrete platform and remarked to an accompanying friend, "I just cant see how this is strong." I can see how it's strong now. Good job, boffins.
This is a really informative visual example of flexural and shear failure..helped me in my project =)
Steel reinforcement be like : your welcome
Incredible.i appreciate both 3d maker and technique developer...👍
This looks like a flexural failure first... perhaps you should have designed the beam without stirrups and cross steel if you wanted shear failure first... Down size the steel or change dimensions of beam... or even bring load point in closer... Just looks like flexural failure first and of course shear may happen afterwards or it can just fail at the flexural failure and no shear can be clearly shown...
What was the force / pressure at which the beam broke?
When concrete breaks do the rocks usually shear with the crack or just pull out.....looking at the bridge in florida i have never seen rocks shear so clean..like the were using soft rocks..??
Very helpful example no need to explain any way thanks
very strong steel bar used and concrete is elastic in nature . after this much bending beam does not destroy. wow
good 45 degree Shear crack
They never should what was the size of the rebar and what was the pressure
how do you differentiate between the shear and flexure cracks generally?
Good question. I would say that initially you're seeing flexure cracks, they start on the bottom of the beam where the bending stress produces tension. The big crack that forms and ultimately causes failure looks like a shear crack to me. It's at an angle of tensile stress created from the transformation of shear stress (i.e., Mohr's Circle).
WisconsinEngineerUWP Thanks! Is there a way to determine what causes the beam to fail in shear rather that tension? I'm guessing its mostly based on lack or excessive reinforcement of either one right?
Ed Cadiri In this case we purposefully under-reinforced for shear and then placed the load so that it would generate a high shear force, but relatively low bending stress. In general, in determining whether it's a shear or moment failure the location of the failure is important (e.g., near support) and also the orientation of the crack (shear cracks are typically at about 45 degrees).
+Mhamad Riyad Thanks! so it's mostly related to the location of the failure and thanks +WisconsinEngineerUWP for mentioning a similar explanation above.
Hydraulic press vs concrete beam
They started as flexural cracks and once shear was higher than let’s say 3.5sqrt of f’c transition to tension cracks
I keep thinking that ram will fail and flip the metal block at someone watching it so close and cut them in half.
shear failure starts from top of the beam...
there is no shear or flexural failure both are principal stress failure in tension where principal stresses are in angle close to supports. Crack is always perpendicular to tensile stress. In short beams support region is problematic in long beams mid cross section is problematic. I am just typing this because people sometimes dont realize its more about principal stress trajectories than strictly trying to isolate shear and flex