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...
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?
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...
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...
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...
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...
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...
Hi,
I am using ACI to design a building.
According to ACI, shear wall is designed as an ordinary reinforced shear wall or special reinforced shear wall (for high seismic level).
1-What about Wind loads,if I want to design the structure to resist wind loads not seismic load, how do I know if I...
Hi,
In ASCE 7-10,2.3.2 are given the basic combinations for strength design:
1. 1.4D
2. 1.2D + 1.6L + 0.5(Lr or S or R)
3. 1.2D + 1.6(Lr or S or R) + (L or 0.5W)
4. 1.2D + 1.0W + L + 0.5(Lr or S or R)
5. 1.2D + 1.0E + L + 0.2S
6. 0.9D + 1.0W
7. 0.9D + 1.0E
In equation 4 and 6 , W refers to...
Hi, I have a question:
In modal analysis, to get the displacement of a story we combine story displacements obtained from each mode.what is the reason behind this?
