Bombadilla
Structural
- Jun 26, 2023
- 3
I am working on a detail where a concrete wall is subjected to concentrated loads perpendicular to the wall. In my case, we don’t have reinforcement to handle the bursting tie forces. The wall is not subjected to significant tensile stresses in the bursting region from other loads. There is surface reinforcement in both sides of the wall, but not in the area where the tensile stresses occur.
I am trying to find out when bursting reinforcement becomes strictly required according to code (in my case: the eurocodes (EC2). EC2 gives no guidance where there is no reinforcement to resist the bursting tie forces, but in designers guide to EC2-2, an approach is where the concrete tensile strength is utilized is given.
My interpretation of EC2 and the designers guide to EC2-2 is that no bursting reinforcement is required if the transverse tensile stresses do not exceed the design concrete tensile strength , and that the bearing pressure is limited to σRdmax=0.6ν' fcd (EC2 expression 5.56), provided that the concrete is otherwise unstressed in this direction from other loads. However, my gut feeling tells me this can be very conservative in some cases.
In my case, the concrete extends practically indefinitely in the transverse direction, and such the strut will be confined by the surrounding concrete, possibly allowing for a greater allowed bearing pressure. The way I see it, the concrete within my strut would not “know” if the confinement comes from bursting rebar or confinement from surrounding concrete. Either way, bursting cracks must occur before enough tension in bursting rebar is mobilized to balance the forces, and one could argue that the surrounding concrete is much stiffer than this rebar, such that the confinement in reality comes from the concrete.
So my questions are:
Is it acceptable to not have bursting reinforcement even though the transverse tensile stresses exceed the concrete tensile strength, provided that there is enough surrounding concrete to achieve transverse equilibrium?
Can a greater bearing pressure than σRdmax=0.6ν' fcd be allowed, considering the confinement of the surrounding concrete?
I am trying to find out when bursting reinforcement becomes strictly required according to code (in my case: the eurocodes (EC2). EC2 gives no guidance where there is no reinforcement to resist the bursting tie forces, but in designers guide to EC2-2, an approach is where the concrete tensile strength is utilized is given.
My interpretation of EC2 and the designers guide to EC2-2 is that no bursting reinforcement is required if the transverse tensile stresses do not exceed the design concrete tensile strength , and that the bearing pressure is limited to σRdmax=0.6ν' fcd (EC2 expression 5.56), provided that the concrete is otherwise unstressed in this direction from other loads. However, my gut feeling tells me this can be very conservative in some cases.
In my case, the concrete extends practically indefinitely in the transverse direction, and such the strut will be confined by the surrounding concrete, possibly allowing for a greater allowed bearing pressure. The way I see it, the concrete within my strut would not “know” if the confinement comes from bursting rebar or confinement from surrounding concrete. Either way, bursting cracks must occur before enough tension in bursting rebar is mobilized to balance the forces, and one could argue that the surrounding concrete is much stiffer than this rebar, such that the confinement in reality comes from the concrete.
So my questions are:
Is it acceptable to not have bursting reinforcement even though the transverse tensile stresses exceed the concrete tensile strength, provided that there is enough surrounding concrete to achieve transverse equilibrium?
Can a greater bearing pressure than σRdmax=0.6ν' fcd be allowed, considering the confinement of the surrounding concrete?
