Which one of these is the easier of the two? I just finished my final exam for concrete, and my god that was the hardest class I have ever taken in college. I'll be very luck to even get a C-. And I got solid A's in structural analysis and statics. I hear steel is a bit easier but what are your experiences with these two classes?
This is painfully stupid, sorry.
My understanding: concrete has great compressive strength, but snaps like a breadstick if you try to bend it.
So to fix this, you put steel rods through your concrete, which are plenty springy and will resist the strain.
But, like... you've put a stick of licorice down the middle of your breadstick. Now, sure, the whole thing won't just snap in two, but the crispy shell is still going to crack before the licorice gets a chance to spring.
Why doesn't the concrete break before the steel takes the strain?
"Reinforced Concrete Design", Wang, Salmon, Pincheira, Parra-Montesinos, 8th Edition, Oxford University Press, ISBN 978-0-19-026980-7
Any suggestions on where to find a copy for a cheaper price?
Hi everyone.
Hopefully this post doesn't break any rules but I'm in need of a bit of assistance.My background is not civil/structural engineering but I've got a research task which requires some comparison and understanding of steel reinforced concrete beams and I'm hope I can get some answers here.
I'm attempting to compare two types of beams based on a structurally functional capacity relating to an environmental assessment study but due to some unforeseen circumstances, our expert on the subject is not available anymore.Although i had some statics and dynamics courses relating to homogenous materials and a bit on FRPs in the past, I've never worked with concrete or reinforced concrete.
Can anyone give me some reference books or great videos that gives you an overall understanding of steel reinforced concrete beams in terms of calculations and considerations when being implemented?
Were attempting to compare them to different materials based on beams but we need something that would be the most valid comparison despite the materials being different. Im guessing some building codes or standards based on certain types of failures or deformation would be considered the maximum load but I'm unfamiliar with how civil engineering treats those in terms of material testing and also in regards to safety factors and how to measure them in terms of a served function so any help would be appreciated.
Edit:
Thanks everyone! Got some great info that helped a bunch
In Wight's textbook(attached below), presented an iteration method. In which the final answer from this method won't be exact, unless the stepping size is infinitesimally small. Whether the compression steel is yielded or not, it will be determined and accounted during this process, but still, the final answer won't be exact.
https://preview.redd.it/ilno73ciyjp61.png?width=675&format=png&auto=webp&s=2b73e5cf2e1102d7f4da7652943843814eca97a7
Instead of using this method, would it be better to just solve for the neutral axis directly from the equation?
Assuming tension steel is yielded.
T = C
T = Cc+Cs
A_s*f_y = Ξ±_1*f'c*b*Ξ²_1*c+A'_s*(f_y-Ξ±_1*f'_c) in case compression steel is yielded
A_s*f_y = Ξ±_1*f'_c*b*Ξ²_1*c+A'_s*(E_s*(c-d')*Ξ΅_cu/c-Ξ±_1*f'_c) in case compression steel is not yielded
In which, we can determine which is the correct answer by finding the strain of the compression steel using:
Ξ΅'s = (c-d')*Ξ΅_cu/c
and if the Ξ΅'s matches the condition of that equation, that c is the correct c. With this method, the final solution will be exact, it might not matter much but I think it's still better than near-exact solution. If this method is incorrect or the assumption is incorrect. Please let me know.
Thank you very much!
Add: this is for general rectangular shape case.
Hello all,
I have this confusion with how codes restrict or free the depth and analysis of structural design.
When I was in college for my bachelor degree the concepts and principles that I learnt regarding structural analysis and reinforced concrete design are still βminimallyβ relevant to the design work that Iβm doing now at a consultancy firm. I stressed minimally, because the relevancy is only ever so lightly that itβs not practical at all.
So as a junior, I can only learn from the code, and And understand the requirement of the code
While I supposed all bachelor level structural or RC design cover similar topics. The codes that engineers use would not be the same in different region, and I suppose the difference stems from how detail they require the structures to be designed and analyzed.
For example the firm that Iβm working on, in their structural calculation report, checking of the vibration of the building is never reported, but a report from another country that we are reviewing as independent checking engineer did analyze the buildingβs vibration.
Does that mean that basically codes of that countries require vibration to be analyzed? Or they are just doing it because they are trying to be more detailed in their structural analysis?
Another doubt regarding this is how detailed the design need to be, of course drawings differ from country to country, but shouldnβt there be some basic principles in producing structural drawings (while not being too detailed and meets the codes, but still effective enough for the contractors to understand the drawings?
My questions might seem loaded, but I have had these doubts for a very long time.
Anyone know how to get this? I always just spend gold but getting expensive the higher I go.
Hello!
Quick question about a project. I am assuming this is a bit of standard practice I haven't been exposed to yet so hoping this is simple stuff and easy to answer.
I am working on a small commercial remodel project. There are reinforced concrete shear walls along the exterior of the building.
The client wants to expand one of the doors from a relatively standard size (34" wide "96 tall) opening to maybe double the width.
Of course I will run the numbers to be sure the shear panel is good to go with a larger opening.
My question is more about constructability. I know there are reinf. bars at the corners of the original rough opening [(1) #5 diagonal bar, 4'-0" long] and vert reinf. bars running along the side of the rough opening [(2) #5 vert bars]. My understanding is these are to prevent cracking around the rough opening. Is there a constructible solution to provide the same function after expanding the width of the door?
https://preview.redd.it/65x0by9iwmo61.jpg?width=3264&format=pjpg&auto=webp&s=19a77e5e26b3a030051c3f2a3f58a85d951afba4
https://preview.redd.it/wnmw4wk7l7n61.jpg?width=1024&format=pjpg&auto=webp&s=e36256823d7cf542be49ba01e8e01409989b8c0d
In the beginning of the 20th century the architects did not have enough information regarding the corrosion resistance and longevity of the structures made with reinforced concrete. Nowadays, it is well known that with time a steel rebar in concrete rusts, expands, and damages concrete. Thus, reinforced concrete structures have a limited service life. BS5400 standard, for example, sets it to 120 years for monumental construction and bridges. Basically, it means that everything that is built nowadays will be gone in a few hundred years.
In comparison, the Second Gateway Bridge in Australia was designed to have a 300-year service life. Engineers used stainless steel for reinforcement and at least a 75 mm concrete layer to cover the stainless steel rebar from environmental elements. It is estimated that these measures will prevent corrosion initiation for 280 years.
Hagia Sophia has been standing for 1500 years, Pantheon (non-reinforced concrete) for 2000 years, Les Ferreres Aqueduct for 2000 years, Notre-Dame de Paris for 700 years.
Now, let's have a look at the modern monumental construction. For example, Sagrada Familia - the best of best. Guess, what will happen when the ordinary (non-stainless) steel rebar in the load bearing column of Sagrada Familia rusts in 100-200 years? They indeed use the stainless steel rebar at Sagrada Familia, but, as far as I know, it was not used for the load bearing columns!
Gaudi did not have access to scientific studies regarding longevity and the corrosion resistance of the reinforced concrete. Knowing about these problems now, would it not be better to have coated steel or stainless steel load bearing columns without any concrete covering them?
I am afraid that nothing will remain from the contemporary fast food architecture*'s* era in a 500 years time. I am calling it a fast food architecture because it is fast, cheap, and unhealthy (not sustainable) for the environment.
What do you think?
Hi All,
Has anyone of you designed a long-span conventional RC beam? I am design the first long-span RC beam and I am a bit worried. The beam is 14m long (50ft), the slab is 300mm thick (1ft), live load 10kN/m2. Because the slab bottom needs to be flat so the beam is located on above the slab, it is like invert βT-beamβ. The slab and beam are supported by RC wall. I considered the wall and beam/slab as rigid connection, therefore the negative moment is quite high about 1100kNm at the supports, which I put 5T32, midspan 10T25in 02 layers. I checked cracked width and deflection(30mm) is ok, but still a bit concerned. I wonder if I should put a haunch beam at the support above the slab?
Thank you a lot
Update: beam total height is 900mm (incl.300mm slab). Concrte grade: C35/45. RC Supporting walls: 400/500mm
