Reader Forum

After 25 years of designing structural steel & reinforced concrete, I find myself asking “so……why?”

 Why have I always used 1 ½” instead of the AISC recommended 1 ¼” ? 

Embarrassingly enough I will have to say “because this is what I was always taught to use.”  But that don’t make it right. "I hear a song in here somewhere…"

 I have a client who, I know, will scrutinize my upcoming design to the Nth degree.  If they see 1 ½” edge distances I will be asked why.  What rational, engineering reason would I have to use 1 ½” edge distances instead of 1 ¼”?  Other than it’s easier to read on a tape measure.  These are distances I will be showing on cap plate details, connection plate details, clip angle details, etc.  Btw, all of this steel will be galvanized.  This structure is comprised of a few monorails that will be extensions of existing monorails and will be connected (hung) from some existing roof framing steel, (roof steel is circa 1967 ). Thank you for all your help on this.

Hi,

I work in gas turbine dept.

we all know Gas turbine is basically anchored to the foundation and in my case, at the ground floor.

Now, to design the GT so that it does not dislocate bcoz of earthquake, if i am not wrong, I should actually design the supports.

I would like to know in which category the below case falls.

case: GT bolted to foundation at ground floor - need to be seismically designed for dislocation only… i am not worried abt the structural integrity of GT.

As per code books:

Buliding structures

Non Building structures similar to buildings

Non Building structures not similar to buildings

Non Structural  components.

Again, I am stressing at the point that i would like design the mentioned case only for disclocation, not for structural..

I will be grateful if detail explanation with reasoning given

Thanks

Venkat

Hi,

Can anyone provide me with some guidance as it relates to the design of a bolted flange plate column splice. Its for a SMF system and my thinking is that since AISC 341 9.9 requests the splice to have a required flexural strength = RyFyZx then this calculated moment should be transformed into a tensile/compressove force = RyFyZx/D where D is the depth of the column.This force can then be checked against the tensile yield and tensile rupture strengths of the plate (apart from all the other checks to be made.

The splice is for a W14×233 column and belive that this is the reason that I am getting some rather large plate and bolt sizes.So far its 10 inch and a half A490 bolts per column end and 2 inch plates, both sides of flange.Im also guessing that CJP welds may probably be more economical here. Any guidance appreciated

I want to know how to design plate girders for a I section beam wich height is variable. thanks for your recommendations. best regards.

Will a full-pen weld for a moment connection help with the shear capacity of a connection?

Hello all. I am designing a reinforcement of an existing steel structure, truss type. the structure is for 2 belt conveyors, 180m horizontal lenght and 21m height, the trayectory is a curved on a seccion of the truss. the model of the reinforcement is finished but i want to know if there is a standard or code about construction (because of the structure is prestressed and predeflected). what codes or standards are available for this case in construction? thank for your kindness.

If we provide expansion joint at roof purlins only (at 125 ft lehgth). Do we need to consider temprature load for building. Building is 350 ftx185 ft and 175 ft high industrial building. temprature variation is 80F. With expansion joint loads are very high at vertical braces location and seems unreasonable to design for these loads. Please advice. Thanks

Hello all,

I am currently building a small steel structure using a 9-foot high 4×4-inch square tubing, mild steel, 1/4-inch thick, to vertically support another non-moving horizontal beam.

I am desperately trying to find a place/chart/website/anything that can give me a rough idea if I am relatively safe in terms of vertical load capacity of the 4×4 post (it’s plum).

The load will potentially be as much as 5,000 pounds.

Any help would be so much appreciated.

Thank you in advance.

When a stair was placed with the treads with respect to Run and Rise as specified in Design Drawing, there is a possibility that the tread hole may exactly come on the mitre cut of the Stair Stringer. What may the best possible solution in such cases?