I have viewed other threads over the years about discussions on this matter and have read/researched information with respect to this and my conclusion is there is very limited information available. The item I am trying to better understand is thermal expansion in roof systems and how to...
When warehouse building dimensions get rather large, it is typically to put expansion joints in a metal roof deck. As the roof deck is being utilized as a diaphragm, a vertical brace system would typically be employed at the expansion joint location to maintain a simple diaphragm design...
So if I am understanding this correct, you typically do a thickened slab/grade beam running parallel with the exterior foundation frost wall? What are you then using for the tie mechanism for the anchor bolts from the grade beam?
Transverse direction I am not worried about as I am designing these as stand alone pier/footings.
For the longitudinal loading, as my sketch showed and you eluded to, it seemed like a tension system back to the adjacent pier/columns was the route to go. Based on the loads I have with the Omega...
Have a pre-engineered metal building that is located in a seismic design category C area. Per the adopted code, IBC 2015 and ACI 318-14, I am having a hard time distributing the horizontal loads from the seismic bracing. I was utilizing Hilti's Profis software and can not get a pier on its own...
Our client is really questioning the design of our purlins and want to make sure I am applying a section of the code correctly as I can not utilize the R-value method that pre-engineered metal building suppliers utilize in their designs.
I have calculated the z-purlin capacity connected to a...
I have computed values based on AISI S100-2012 and the distortional buckling strength seems to be controlling the design over the LTB capacity with discrete bracing. The member sizes become a little large than what one would expect if went the route of a PEMB supplier, but this was bound to...
Are there any published values for Cee & Zee sections used as purlins when attached to standing seam roofs. Per AISI, there is a reduction factor determined in accordance with AISI S908 that is to be used. I would think pre-engineered metal building companies either have their systems tested...
Not finished yet. I did not see this first hand, but what you are describing is correct based on what we were told and makes sense. The beam began bowing out (toward the direction the picture is taken from) along with the beam web curving with the apex of the deflection in the same direction...
KootK,
I thought you had mentioned about potentially only designing the bracing for the moment/forces generated between the points of bracing and not the full moment. As I do not see this in the thread anymore I had a further question on this. Am I losing my mind that you had mentioned...
See attached. There are other multiple issues happening like improper placement of beam over columns, lack of bracing, out of plumb columns. This is currently being resolved with the removal of the precast plank due to time constraints...
Temporary shored with needle beams. Shoring went fine. This support beam also had a cross member combing into it to support a building column. Precast plank bottom cut was horrible (think of 1" square shims spread 3' oc across the beam flange width from left to right for the entire length) and...
This is not in a seismic area. There is a 12' precast wall above the opening that separates the (2) buildings. Half exposed to interior and half exposed to exterior wind. Based on the location, there is only +/- 40 lb/lf lateral force at the beam. The top of the wall is restrained by the...
Attached is my calculation for lateral bracing for beam stability. This is for a 38' span beam with lateral supports (diagonals to the roof deck from the stiffener near the top of the beam flange). These forces seem really high. Am I applying this section of AISC...
What is the lateral brace force at the end of a beam that is simply supported. Take for example cutting in a new opening in a wall that only has dead weight (CMU or Precast). A new steel beam is placed over the top of columns on each end for a steel frame in the opening. What is the required...
Currently working on a project that incorporates purlins (light beams- 12B16.5) at 9' oc for a building that was constructed in 1962. Looking at replacing RTU's that are heavier and am wondering if there was different design procedures +/-60 years ago that would allow these purlins to have the...
WARose,
Not avoided but restrained/resisted I guess is a better way of putting it. I realize that a net component both horizontally and vertically will be present. Worst case will be with only one side loaded as in the following attachment. My opinion is that the "horizontal component"...
Have a project we are working on for a concrete batching plant. The design utilizes steel hoppers that sit on concrete beams that also support the divider walls for the different hoppers. See the attached rough sketch. Where I hope to get some input is with respect to the eccentricity that is...
Thanks for all the helpful opinions on this matter. It seems this subject area is up for debate among many engineers. I can see both sides of the spectrum and will probably use a hybrid to develop a design that per engineering judgment seems reasonable.
