We have a project where we are adding new RTU's and replacing the existing roof with increased insulation. During our analysis of the roof for the new RTU's, it was determined that the ground snow load increased from 40 PSF to 50PSF in the mid 2000's (we are in a site specific location). The...
I'm working on a project where I received structural calculations for a piece of equipment which is around 10'x12'x35' tall and weighs approximately 100K. We are responsible for the base plate design (a bit unusual), anchorage and foundation. After reviewing the calculations, I discovered that...
I'm currently designing the runway beams for a 26 Ton crane with columns at 20'. I'm having significant difficulty trying to determine the best way to design for lateral torsional buckling. For the purposes of this discussion, I will be looking at a W30x116 with a C15x33.9 Cap Channel with using...
I have a project where I have somewhat large shear forces going into W10 beams. We are trying to control depth and are restricted to using W10's or less. I am hoping to use a W10-W10 connection, however due to flexural yielding, flexural rupture, and local web buckling the connections are not...
I'm the EOR for a small one story building where the contractor has installed the anchor rods slightly off from where they should be. AISC code of standard practice indicates that anchor rods should be placed within 1/8" in any bolt group and within 1/4" between columns. For a project of 48...
I recently got a call from a contractor who mistakenly installed 3/4" anchor rods where there should have been 1 1/2". Due to reduced loads during VE, the 3/4" anchor rods actually work on a 20"x22" pier however they will not work on a 20"x28" pier with the same bolt spacing, embedment depth...
I'm working on the foundation design for various industrial storage tanks with some significant uplift/moments (some are 60' tall and about 12' in diameter) and a tall exhaust stack which is about 6' in diameter and over 100' tall. As you can imagine, uplift is a significant concern. The...
When designing a the anchor rods that go into a pier for tension and shear, the interaction equation in appendix D is Nua/Phi*Nn + Vua/Phi*Vn < 1.2. I believe the strength is the governing limit state for both shear and tension. But if you design a shear lug to handle the shear, is this...
I started looking into how RAM calculates the wind load and for a building approximately 16.5' tall with a 2.5' parapet. Based on the building characteristics, the qz at the top of the parapet is around 18psf and with the GCp =1.5 for windward parapet and -1 for the leeward parapet (per section...
All,
i'm working on a small pre-engineered building foundation design where we are using hairpins to tie the concrete piers (in the NE so exterior foundations are 4' down) into the slab to assist in resisting the horizontal thrust. In addition, I was planning on tying the perimeter foundation...
I've recently noticed that in the 9th edition, Vh is defined as the maximum of 50% of the concrete beam width [Vh=(0.5)*0.85*F'c*Ac] and 50% of the steel beam section (Vh =0.5 As*Fy). The thirteenth edition calculates V' as 100% of these same areas (eq. I3-1a V'=0.85*f'c*Ac or I3-1b V'=AsFy)...
I'm currently working on a project with existing composite beams (which i haven't looked at in years). I am using enercalc to check some of my work and have come across some VERY basic disagreements with some of enercalcs results.
I have a W24x55 with a lot of concrete area (my effective width...
Can anyone give a more defined process for designing the jambs at the end of windows? I'm using the SBEDS program, but i am finding it difficult to determine the load on the window.
Any help would be great.
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I'm working on a project where we are checking an existing composite floor system for additional equipment loads. The existing infill beams are W16x26 with only 10 shear studs on them. Given 3/4" dia, weak stud the beam would be less than 25 % composite action. Adding more steel would only make...
Has anyone looked at ACI 530-05 Chapters 2 (allowable stress of masonry) and 3 (strength design of masonry) and noticed the differences between them?
I'm specifically looking at section 3.3.5, Wall design for out of plane bending and i've found that there is no similar section in ASD. After...
Is there any easy way to see shear/moment diagrams for complete beams (ie, not just from node to node, but from support to support)? I understand that you can see the shear/moment diagrams for a specific beam number, but after creating physical members in the steel design module, i would like to...
I am a structural engineer on a project where we are putting 8" cmu walls (approximately 12' high) on top of an existing 4" slab. I'm not overly concerned with the bearing of the cmu on the slab (if the slab cracks it's acceptable), however even if i tie the wall at the roof, does anyone have...
I have an addition to an existing building. The existing building is approximately 150' long with a relatively flat roof. The new building is a hip roof with 25' eave to ridge distance and a slope of 3 on 12.
I believe i should be treating this like a hip roof (with an unbalanced load) with the...
