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Hello All, How does one determine if differential settlement in a high rise building is dangerous or not? What code and what section of the code addresses this issue of differential settlement and gives guidelines as to what is acceptable or not? Thanks for your help. JS

Hello All, In making employment decisions, how much weight should a bonus carry? Employers seem to be more willing to offer a higher bonus than to increase the salary of a potential employee. What are your thoughts on this? Is it better to go for a higher base salary and sacrifice the bonus...

Hello All, I am trying to find opinions on the age old question of whether an aircraft hangar is to be designed as enclosed or partially enclosed. My take is that it is an enclosed structure because the hangar doors are not permanent openings. Some Engineers believe it is partially enclosed all...

Is anyone familiar with Section D3.2.1 of the 1996 AISI Cold Formed Design Manual and its applicability to a through fastened roof? The load PL that is calculated in this section is not very clearly defined. Is this the load that must be resisted by each purlin brace only along the roof...

Hello All, I know that one is not supposed to use tension-only bracing in seismic zones D and above (4 and above in the UBC). However, I can not seem to find the particular section of the code where this is addressed. Does anyone have a reference to this? And also what portion of the bracing...

I have a situation here. We designed a riding arena structure and asked that the erector put up the steel using turn-of-the nut method since all the bolts were high strength A490 Bolts. The Erector does not indicate a problem with this and goes ahead to erect the building. Fast forward a few...

All, I was wondering if anyone could share their experiences on this subject. In PEMB, typically, the clear span frames will deflect more than the Endwall frames that have bearing columns supporting the rafter. As a result, the deflections in the main frames will be more than the deflection in...

I work for a small steel manufacturing company. Recently, our purchasing department says that they are having a hard time finding flat bar steel in 50ksi because the mills are moving away from that and are concentrating on the lower yield 36ksi material. I find this difficult to reconcile with...

I'm working on a project where the wrong size plate was used for the web during the manufacture of some plate girder columns. These columns have already been fabricated and shipped to the jobsite. Apart from all the acrimony and finger pointing that is sure to occur; I want to have...

Hi All, Are there any prequalified flare bevel welds that are available for use? I have looked through the AISC manual and do not seem to find pre-qualified flare bevel welds. I am attempting to weld a 1-1/4" rod to a flat plate and need to size the weld along the rod/plate interface. Page 58...

I am designing a steel plate girder for a moment frame. My shear flow calculations show that I can get away with welding one side of the Flange/Web interface and simply tack welding the other side. I am trying to find out if this is acceptable practice with respect to Plate Girders. I have...

Hello All, I am having an issue at work that I need some input in. The manufacturing company I work for gets it's steel from a number of different sources. Apparently, our 36ksi steel comes in with mill certs from 45 thru 49 ksi. The practice here is to design at the mill cert yield stress, but...

Hi All, IBC 2000 requires that the importance factors for Seismic, Snow and Wind be increased for Category II Buildings (1.25, 1.1 and 1.15). This is in Table 1604.5 of the code. My question is the code does not make direct reference to occupancy and live loads for mezzanine design. I have a...

Hello All, Does anyone have any idea what the requirements are for the tensioning of Cable braces in the walls and roofs of a metal building? Intuitively, I know that the cables need to the taut so that they are immediately engaged when loaded, but I can't find a specification that seems to...

Hi All, Section C.3.1.3 of the AISI '96 code provides numerous conditions for a roof panel to be considered through fastened. One of the requirements (#8) states that "For continuous span systems, the longest member span shall not be more than 20% greater than the shortest span." I have...

Hi Everyone, I was wondering if anyone could shed some light on the relative applicability of Grade 8 bolts and A490 High Strength Bolts? Are the two interchgangeable? Thanks in advance. JS

Hello, Could you please shed some light on AISC's requirements for the specifying and using steel that has higher yield strength than the minimum given for that grade of steel. For example, How does AISC allow for the use of A500 Grade C steel that has a yield stress of 60ksi when the min yield...

Hi Everyone, Chapter F of the 9th Ed. AISC ASD Manual states that the equations in that section apply to ..singly or doubly symmetric beams including hybrid beams and girders ..".My understanding of this means that the equations would be applicable to built-up beams where the flanges are made...

Hello All, In the IBC 2000 Code, equation 16-28 states that E = p*Qe + 0.2*Sds*D I am confused about the 0.2*Sds*D part of the equuation. What is this part trying to represent? If I have a mezzanine that has a high dead load, would this be included in the "D" part of the above equation? How...

Hello All, Table 1617.6 in IBC 2000 has some limitations called out with respect to building height and seismic category. Footnotes (h) and (i) for the table refer to some limitations to the use of ordinary moment resisting frames with a dead load limit of 15psf. Can anyone please shed some...