6

"CRS" is an abreviation for "Centers". So, for example the statement "Deck Joist @ 400mm crs" means "at 400mm centers", i.e. that the centreline of the joists should be 400mm apart. If you were to measure the gap between the joists, it would be less than 400mm, due to the thickness of the joist itself.


6

The Load-Displacement (or Load Extension) and stress strain diagrams are two diagrams identical in shape. See below. The main visible difference is the values on axis (which are at first glance neglected). So, it is natural when you first encounter them to question why do you want to learn about a stress and strain diagram which has obscure quantities (as ...


3

On top of flexural deflection, the Timoshenko Beam Theory includes a term called "Shear Deformation" that is to account for the additional deflection and shear stress due to shear effect, which is quite samall compared to the effect from the flexural, thus it is usually ignored except higher accuracy is desired. (See figure below) The slope of the ...


3

First thing first, you need to get hand on the ASME Boiler and Pressure Vessel Code (BPVC Code). Starting division 8, section 1, for safety and quality of your pressure vessel. After checking on all relevant provisions/standards, you can use the equations to derive the required wall thickness for your application. Notation σ_H = hoop stress, psi or MPa D = ...


3

Does not apply to this example, but just for completeness: I've also seen CRS as an abbreviation for cold-rolled steel in a material callout in machine drawings, e.g. "1018 CRS".


3

An extended discussion on internal vs. external forces We usually like to describe hinges as "places where the moment is always zero." But, wait a minute, the moment is always zero anywhere in a stable structure. Don't believe me? Let's take a look at the most trivial structure ever, a simply-supported beam with a uniform load: So, it has a span ...


2

It is important to understand what is an internal hinge, its behavior, and assumptions around it. An internal hinge represents a discontinuity in the beam, it carries a pair of equal but opposite force couple, one to each side of the hinge, carried over from the beam segment it supports/connect to, so sum Fy is zero. Another important assumption is the hinge ...


2

Using conditions given in the sketch above, let's do a parameter study. M = AsFy(d - a/2) a = Asfy/0.85fc'b, note, since As, b, fc' and fy are constant throughout this exercise, "a" is constant as well. Let's assume a = 50mm. d = 65, M1 = AsFy(65-50/2) = 40Asfy d = 115, M2 = AsFy(115-50/2) = 90Asfy d = 165, M3 = AsFy(165-50/2) = 140Asfy M2/M1 = ...


2

There are at least two contributing factors to that: a) development of grains (the following is mainly an excerpt from this question ) and this Usually thinner steels exhibit higher yield points (see cold roll sheet catalog page.8) and ultimate tensile strengths (see Steel construction) because, sheets of steel, that come out of rolling processes (especially ...


2

I would say that you can divide them into two groups: At nodes with two member and no external force Node C: CD,CB, Node G: FG, GH Node K: KJ, KL If you write down the equilibrium at node C for x and y you would get: $$x: \quad \sum F_x = 0 \rightarrow CD = 0 $$ $$y: \quad \sum F_y = 0 \rightarrow CB = 0 $$ Same at the other nodes. Note that nodes A, and ...


2

Usually $\kappa = \dfrac{\text{average shear strain on section}}{\text{shear strain at centroid}}$ but the problem with this definition is that it depends on external loading so you can't actually make a table for $\kappa$ values. However, we could make an assumption and define $\kappa$ purely in terms of the shape of the section: $\kappa_i = \frac{1}{\...


1

NFPA 13 is the industry standard on all matters related with sprinkler systems in the USA. However, as a standard, it needs to be adopted by each of the States Building Department to incorporate into the State Building Code. Also, the State may impose additional requirements, as Amendments to NFPA 13, which are also to be met. So, in your case, you shall ...


1

If you take a read more carefully the Eurocode, it says "2% annually". That should be translated that in a full year, there is only a 2% chance to get to that wind level. So one simple way to think about this is that there is one chance in 50 years for that failure to occur (which is considered a reasonable scenario. The more correct mathematical ...


1

For hot rolled , the thicker section cools slower so has coarser pearlite and coarser grain size because the grains have more time to grow larger during the slow cool. A secondary factor is the thicker section is worked less / less strain to refine grains. The lower strength affect of the slower cooling thick sections also occurs during normalize and quench ...


1

Direct answer to your questions: Yes, the opening depth is immaterial in support requirement determination. Round opening is less likely to require support, due to arch action. Wall type is critical when the brick layout pattern affects the available bond between bricks over the opening. If depth of the wall above the opening permits arch action to occur,...


1

Depending on the design, these folded boxes are good for weights between 60 and 300 pounds. The box is "locked in place" because paper or cardboard can not be stretched. The only way you can easy way to change its shape is to bend it, and you the only way you can bend a piece of paper is to shape it into a cylinder. But you can't "bend" ...


1

I'm not a geotechnical engineer, but I believe the gravel is there precisely to prevent the soil behind it from getting saturated. That is, if the soil gets saturated, the hydrostatic pressure will squeeze the water out into the gravel, which then drains the water away, thereby reducing or altogether eliminating the pressure on the wall.


1

Just a few notes here: With or without gravelly backfill, the retaining wall must be designed for the maximum groundwater anticipated for the site. Your geotechnical engineer shall provide this information. The 300mm clean free draining material is the minimum requirement, it is recommended to backfill the entire cut (excavation) with well graded gravelly ...


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