There are multiple avenues through which this can be approached. One is the economics of the construction. As you've mentioned, concrete structures are far cheaper to build than steel, though the ...

You seem to be mixing up a few concepts. As others have mentioned, bending moment is independent of a structure's cross-sectional dimensions. After all, bending moment is simply the sum of $F_i\ell_i$,...

Not only can this be done, but it also is done for concrete structures all the time. The shear reinforcement in concrete beams is calculated using Mörsch's truss analogy model: Source The concrete ...

It depends on the loading conditions. It's important to note that the stress concentrations can be intuitively understood as created by the load's need to deviate from the hole. The larger the width ...

What's an equation? In life there are two types of equations: theoretical equations are obtained from first principles: make some assumptions and then play around with variables until you get a ...

I think your big misunderstanding is in this paragraph: [...] if I were to scan, starting from the leftmost side towards the right. I would initially see a compressive force onto the beam from R, ...

It's a truss bridge. A quick Google Image search will make the difference between the bridge types clear. This is a plate girder bridge: And this is a truss bridge: Basically, a girder bridge uses a ...

Some other answer have touched upon this, but I think it needs to be made explicit: Your mistake is in thinking that civil engineering is about making the lightest structure possible. It's not. ...

Buildings are typically designed with a 50-year lifespan. So a 2% yearly chance of passing the limit makes intuitive sense. But you're right: that'd basically mean we expect the structure to collapse ...

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 ...

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 ...

Let me see if I understood it correctly: You have a rubber block under a uniaxial load (compression or tension). That block may or may not be constrained on one pair of sides (the load is applied ...

Photons either pass through a given material or they don't. If they pass through, it's as if the material isn't there as far as they're concerned (ignoring refraction). If they get absorbed, then they ...

You are correct on both counts. For members under tension, both cross-sections should behave equally, since the limit to the allowable tension force is simply: $$P = f_y A$$ Where $f_y$ is the ...

The lesson to learn here is that you need to design your structure such that it matches your analytical model. Does your model have a transfer of moment between the beam and the column? Then you need ...

While I completely agree with @NMech's answer, let me take a different approach. As I see it, the problem is that you're forgetting something: look at the right-hand side of that equation: $IR_gG_F$. ...

Fair warning, I'll be anthropomorphizing and using metaphors throughout this answer. It helps to think in terms of how the applied force "flows" through the element. It "wants" to ...

We usually describe structures as either statically determinate or indeterminate. However, this determinacy is actually two-fold: there's internal and external determinacy. External static determinacy ...

Dead loads can, in some cases, be beneficial to the structure's safety. For instance, say you have a simply-supported beam with a cantilever and you want to find its bending moment envelope. Depending ...

If we look at each of those fractions individually, their meaning is obvious. Obviously, for a structure under axial load (or bending moment), the applied force must be lower than what the structure ...

There's a reason why they're called "factors of safety" The answer to your question is in its title. When designing a structure, we need to make sure of two things: that the structure will ...

For starters, what makes you think the concrete doesn't crack at the top? Let's assume for a second that it does crack. Well, if we were dealing with a pure concrete beam, that'd be a big problem ...

As insinuated by @Solar Mike's comment, a good first step is to think about the equation which defines elongation, Hooke's Law: \begin{align} \sigma &= \frac{F}{A} = E\epsilon \\ \therefore \... View answer Accepted answer 2 votes To understand the hyperstatic moment, we need to first remember that prestress is, by definition, the application of an internal stress state on the beam. Therefore, it cannot generate external loads ... View answer Accepted answer 2 votes This is a case of a variable-cross-section beam. What you need to do in these cases is separate the cantilever into two parts: near the support it has one cross-section, near the free end, another. ... View answer Accepted answer 0 votes In such exercises, I suggest doing things by steps. Your work goes from the equilibrium equations directly to the internal force equations. Instead, I suggest doing one thing at a time. The ... View answer 1 votes This is a statically determinate structure (four reactions minus one release equals three static equilibrium equations). So we should be able to do this using simple statics:\begin{align} \sum F_x &...

It can't be done Indeed, this problem is unsolvable using only equilibrium equations. Broadly speaking, structures can be split into three categories: hypostatic: when there are too few supports to ...