hi,
I am trying to understand the concept of reinforcement detailing specially in walls.what I know is that to not crash concrete cover we have to avoide concentration of force from compression or tension of rebars.I have found the attached picture on one of eng tip forum and what I want to...
I think I found solution correct me if I am wrong.https://files.engineering.com/getfile.aspx?folder=9ddd26a0-398d-4258-8615-bfe3a39a3fc1&file=IMG_20181111_202634.jpg
hi
Could someone give me the mathematical reasoning behind the mass participation factor formula.I mean how defining it guarantee that it represent the contribution of a corresponding mode?
can you give me a reference where I might find explanation?
I only know the formula of mass participation factor.but how defining it in this way makes it sum up to total mass I could not prove it and this is the problem.and same for my second question.I mean modal participation factor is visible in the differential equations but mass participation factor...
hi,
I am trying to understand basics of mass participation factor.
My questions are:
1-could someone help me figure out why sum of effective mass of all modes equals the total mass of the system.
2-the higher the mass participation factor the more the mode contribute in total response.why?
Hi,
In ACI 360R,chapter 9 in 9.8 and 9.9: design of slabs on expansive/compressible soil.As far as I understood the value of moments are given for a slab on ground with beams and perimeter load.
1-Are these equations for structural slab on grade? or could be used for slab on grades that do not...
Hi,
1-Is it good to use a flexible mat foundation with a rigid superstructure?because it is more economical. I am modeling the flexible raft as a slab on elastic soil, and have checked the differential settlement and found them in the limits.
2-Could you give me a formula that help me determine...
Thank you but I want to be able to do my own chart, in other words determine using FE software if I need to provide an expansion joint or not.so I am trying to understand the concept of this.and i want to know if I always should put additional reinforcement for temperature an if not why
Hi,
I am trying to understand how to determine the maximum allowable length of a building without expansion joint.
The problem is that I see,in case of contraction of a floor under thermal load,that we have to provide reinforcement for temperature what ever was the building dimension,with or...
Thank u
The problem is that aci limits seismic tie beam's least dimension to a maximum of 18 inches.I don't know the reason behind this limitation but it makes me think that adding flexure to the beam might lead to another limitation that I ignore.
Hi
I have an eccentric footing,I need to connect it to a strap footing.and also I need to connect footings with seismic tie beams.
If for e.g seismic tie beams should be designed for axial force=10% column load.
Should I design the strap footing as a column under the 10% axial force and bending...
Thank you for your reply.
How do you design shell for torsion?In the sandwich model nxy=nxy/2+Mxy/dv
But the problem is that if we take the whole cross section of a shell in addition to the moments mxy on the section the out of plane shear create an additional torsion moment about the center of...
Thank you for the reply
Steveh49 I have read FIB.in torsion verification what does dk means?I cant find its definition.
And for in plane shear do I use shear resistance of 7.3-8 or shear transfer of 7.3-33.In aci for shells in plane shear reinforcement is done for shear friction transfer.
WARose thank you
By saying:checking the interaction with axial load, you mean checking the compressive stress if < compressive strength f'c?
And for shear and bending moment design did you divide shell's section into portions and design each portion under it's corresponding loads?
hi,
According to ACI 19.4.9 provision "Reinforcement Required to resist shell bending moments shall be proportioned with due regard to the simultaneous action of membrane axial forces at the same location."
Does this mean that I should treat each portion of the shell's section as a column...
Hi,I am new in post tension design and I am facing a problem.
I had modeled a post tension slab with banded tendons in one direction and distributed in the other.
I have a span,in the direction of banded tendons,where at service load the tension in the top fibers at middle support is almost at...
Hi.I have been told that when using banded tendons in a direction and distrubuted in the other it is preffered to put banded tendons in the direction of shorter spans and distributed in the other direction.I want to be sure if this is correct or it there is no general rule to choose the...
Is this method in p 15(". Recent practice has adopted the use of an effective width equal to the width of the superstructure element imposing the demand, plus one mat thickness either side of the
same element. ")applicable for slabs also?
I am talking in general case.
The finite element programs gives shear force per meter length in a specific vertical plane.
When I choose a vertical plane parallel to a wall for example, I get shear forces per meter length on each node of the plane. If I sum the forces over the whole plane I...
Hi,
I am using a finite element software to design a slab/raft foundation for one way shear.
I am trying to use shear force(T/m)/shear stress results to do my design.for beams we had learned that we consider the total shear force of the whole section,but we didn't learn for a slab/raft how to...
