My firm has been tasked with replacing the bearings on a through-truss railroad bridge. The bridge was built in 1927 and was originally property of the Delaware and Hudson. The span is long so the jacking loads are quite high - the bridge weighs over 700 Tons. Analyzing the connections is fairly...
The PE exam is coming up on Friday and I keep stumbling on a certain problem in my practice tests.
The problem is very simple and should be easy points on the actual exam if it appears: "Given an allowable stress and a bending moment select the lightest wide flange". Cake, right? Mn=Mp=FyZx...
We have a digital copy of ACI's Manual of Concrete Practice. I am sitting for the PE in April and am compiling code. NCEES says both documents referenced in thread title are required (for Construction depth). For some reason our digital copy of SP-4 is just one sheet - it must be incomplete. ACI...
I have always thought that proper detailing of a reinforced concrete wall with two layers of vertical reinforcing was for the hooked portion of the dowels in the footing to point towards one another.
However, I have seen this detailed the opposite more often than not and my supervisor and...
I'm curious if anyone has approximated a modulus of subgrade reaction for rigid foam insulation beneath concrete slabs.
I see regular foam board used in residential construction frequently - not the 40-100 psi hi-test variety that is preferred for under slab use. I am curious how you would...
This problem comes up for me a lot. Most clients don't want a broom or float finish on their exposed flatwork. But when the building is subject to freeze-thaw (Unheated garage, barn, etc.) or when the extra R-Value of AE Concrete is desired, there aren't many other options, as far as I know...
http://www.newson6.com/story/15059775/heat-buckled-highway-blamed-for-pawnee-county-crash
I understand concrete will undergo some thermal expansion, but I didn't realize to this extent. Usually we're more worried about it shrinking.
I wonder if AE concrete is not used in the south since...
Has anyone made the move from working at a design firm to a GC?
I like elements of design, but really only find myself excited by concrete and timber design. I'm doing more and more steel and after switching from an A/E firm to an engineering firm specializing more in commercial and...
I'm headed to a job site today to inspect a project in which they rebuilt the existing flat roof framing, only to later find out that many, many courses of existing brick on the exterior bearing walls are in really poor shape (I have my own theories on the progression of events). By that I mean...
Title says it all - any suggestions on getting forces from windward walls into perpendicular shear walls without roof sheathing? Building in question is quite modest - 16x24 single story.
Regarding Equations j4-3 and j4-5 in AISC Manual (13th edition, spec), it is clear that Anv in each is a different area, or else one would not need to check j4-5.
My understanding is that Anv for Shear Rupture is based on the Whitmore section, and that Anv for Block Shear is based on the...
In analyzing a RAM Elements model of a large truss with many members failing, I'm having trouble with a couple things:
Section Properties: A little time consuming to do out by hand, but not really a big deal. Until I get into FT Buckling checks....
Flexural Torsional Buckling: This calc is...
I'm designing reinforcement for some turn-of-the-century long-span trusses. Many members failing in compression need to get built up, so I'd like to use enercalc to speed things up. Does anyone know how to import shapes/sections from the Custom Section Properties module into the Steel Column module?
For 90 degree wall dowels (from ftg's or mats) I have have typically considered that the 'A' dimension, or that which goes into the mat or footing lapping transverse bars, should be Ld, or 1.3 Ld.
It has never occured to me, until now, that the 90 degree dowel could be considered a standard...
My current project has two buildings that are apparently required to be 'non-combustible' and as such have CMU walls, l.g. steel roof trusses and metal roof deck. The architect wants asphalt shingles which require 3/4" sheathing for a nailing surface.
I'm comfortable designing for lateral...
In analyzing simple, low rise structures with gable roofs and flexible diaphragms it is not difficult to distribute lateral forces and check shear walls (provided geometry is somewhat simple).
With wood trusses I show blocking in between truss heals and usually use Simpson H2.5A's (they're...
I sometimes am required to design or detail open structures (usually just accessories to structures like canopies over entry ways, small generator enclosures etc.) which end up as pole-barn style with knee braces.
I am usually under pressure to use no braces from architects. I am trying to...
At the risk of asking a vague, open ended question, does anyone have any basic information they'd like to share about C.I.P. exterior concrete stairs?.. I guess I will elaborate.
Doing a small (but wide) set for an existing building - landing is a suspended slab which is being removed and...
I dont do too much wood design but find the need occasionally. I have typically guessed an initial rectangular column size with le/d < 50 , applied applicable adjustment factors and calculated Cp , column stability factor. In trying to become more efficient I have found some tables published by...
I'm headed out this morning to measure an existing entrance slab to a Town Hall building. Bellow it is a "basement" but its really more of a vault that was used until the 60's as a drunk tank and then until the 80's as an embalming station - spooky.
We're designing the suspended entrance slab...
