I need to calculate the vertical load capacity of a 5"-thk. reinforced concrete roof placed on a metal deck that spans 7' between beams. Concrete is the normalweight 3000 psi. I have steel deck manufacturers' catalogs that provide load tables for the allowable vertical load capacity for their...
I would like to hear from practising structurals, and others, out there of quick and reasonably accurate ways to estimate beam sizes and weights when, for e.g., the AISC 9th Edition (Green Book) or 13th Edition (Black Book) are not easily available, when you are out on a job-site, when you just...
I have got a question about the analysis and design of tapered-section columns, either in a pre-engineered building, or in a steel structure. What is the best way to approach this? What is the theory behind it?
Now, I have done some design for columns for purely axial loads, and for...
I've got a question about when to design torsion in structural members, say steel, but maybe reinforced concrete as well. A colleague of mine was designing structural steel members for bending and axial loads, but not for torsion and was put on the "hot seat" when his calcs were checked by the...
I have got a question about shear reinforcement(a.k.a. stirrups, ties or links) for the bottom of column bars that are embedded in deep slabs or footings, esp. for deep footings (>= 36").
Do we need to provide stirrups in this part of the column? Please see Sketches #1 abnd #2 below. Should...
I've got a question about the theory of bracing for steel structures, primarily vertical bracing but it applies to horizontal bracing also. Bracing primarily provides a load path for the lateral loads to be transferred to the foundation by being able to take tension and compression, right?
It...
I am trying to determine all the possibilities for the hickness of a column base plate, t (ASD Method) for axial loads only without any substantial moments. The AISC Manual 9th Ed on Pg. 3-106 provides that t be the larger of or {2m or 2n} * SQRT(fp/Fy). My CERM 8th Ed also states that this is...
Does anyone know the formula for Lu, please? Lu is the maximum unbraced length of compression flange at which the allowable bending stress may be taken as 0.60 Fy.
My Civil Engineering Reference Manual, 8th Ed. on Page 59-3 provides Lu as the larger of 20000*Cb/((d/Af)Fy) or...
I am trying to find out how to calculate the term "r subscript T". rT is used in the determination of Lu, which is the maximum unbraced length of compression flange for which Fb=0.60 Fy. In PPI's Civil Engineering Reference Manual 8th Ed on Page 59-3, rT is defined as the radius of gyration of...
I am designing shear lugs for my base plates on my mat foundation. The base plate is sitting on top of the mat foundation and the shear lug and shear lug pocket where they do occur (around vertical bracing areas, primarily) will interfere with the top reinforcement of my mat.
To get a feel of...
I am designing shear lugs for my base plates on my mat foundation. The base plate is sitting on top of the mat foundation and the shear lug and shear lug pocket where they do occur (around vertical bracing areas, primarily) will interfere with the top reinforcement of my mat.
To get a feel of...
Is anyone here familiar with AISC's Base Plate and Anchor Rod Design 2nd Edition? On Page 36, the concrete breakout cone area for group is written as [3(13) + (4)(3)(13) + 4 ] = 1849 in2. How did they get they this number? Is it a typo?
Can anyone provide the concrete breakout cone area for...
I have got a question about making use of friction in the design of shear lug, or shear key, for base plates. AISC allows the use of friction, with a coeff. of 0.55 between steel and grout. However, I talked with my colleagues and most of them do not make use of friction to reduce their shear...
I need feeback on the spacing or cover dimension,"c", used in the determination of development length for rebars in tension. "c"
ACI 318-02 states, "Use the smaller of either the distance from the center of the bar or wire to the nearest concrete surface, or one-half the center-to-center...
Dear all,
I need to seek clarity on the definition of d, effective depth for a slab or a footing. I have always thought that d is the depth from the top (or bottom) of the slab/footing to the center line of reinforcement.
Now, one of my colleagues is saying that d is actually the distance...
I have got a question about the behavior and analysis of batter piles supporting a pile cap. Hope all the foundation guys, esp. batter piles experts, will have a go at it. This post might be a bit lengthy, but not extremely challenging, so please don't be put off, ok?
Imagine, if you will, an...
I have got a question about expansion joints in large slabs or foundations. Are expansion joints specified for such foundations? What is the maximum distance to place an expansion joint? If possible, please provide a reference. I am working on a large reinforced mat foundation, about 500...
I've got a question about punching shear and piles. I am designed a piled isolated spread footing. I have several pile caps, with no. of piles ranging from two to six. For this exercise, let's say we have six piles.
Now, each pile would have a certain allowable capacity, calculated by...
