Concrete Definition and 143 Threads

Hi, I am designing a concrete roof slab that span across 12m long and 9m width for my living area. The support columns are placed in each 4 corners and they are 300mm x 300mm size. The concrete slab roof is cantilevered out by 1.8m on 3 sides (not all 4 sides) with the thickness of 150mm. At the...

Need to move some concrete powder, would like to use compressed air or a blower. I will need it to vacuum and convey the product, the storage vessel is broken and there is no way to gravity or manually feed it. The vertical distance is 8-10' and no more then 20' horizontal. I have played around...

Homework Statement A worker lifts a 20.0-kg bucket of concrete from the ground up to the top of a 20.0-m-tall building. The bucket is initially at rest, but is traveling at 4.0 m/s when it reaches the top of the building. What is the minimum amount of work that the worker did in lifting the...

I have a large machine that must be installed on concrete foundation. It can have no more than 20 micron deflection. Are there different types of concrete? The specs i have from the manufacturer recommend Foundation block reinforced concrete C30/37. this is 1500 mm deep foundation that is 7730...

Hi, as the compressive strength of concrete formula is max load applied/ surface area, could you say that the compressive strength of concrete is inversely proportional to it's surface area or this would make no sense as the concrete with a smaller surface would have a smaller max load anyway...

Homework Statement In an electrically heated home, the temperature of the ground in contact with a concrete basement wall is 10.7 oC. The temperature at the inside surface of the wall is 21.4 oC. The wall is 0.17 m thick and has an area of 6.4 m2. Assume that one kilowatt hour of electrical...

I'm looking at the dynamic state of heat transfer through a concrete slab. Suppose heat is turned on at t=0 and the coils/tubing are 6 inches below the surface. Is there a formula or way of calculating the temperature at the surface at time = t? I found a formula for thermal lag on wikipedia...

I've made a program with Mathematica that will compute the load along with the moments sustained by a concrete column given the stress block area and orientation(in other word the neutral axis center location and the angle it makes with the horizontal). However I am facing an issue with setting...

I have just watched a MythBusters episode investigating whether a concrete glider could fly. They conclude that it was plausible on the basis of a model concrete glider 'flying' 34 feet while dropping 9 feet, giving a glide ratio of nearly 4:1. Now if I recall correctly, the launch speed of the...

Buoyancy -- block of concrete is being raised from a lake Question; A 50kg block of concrete is being raised from a lake. What fraction of its weight in air is required to lift it while submerged? My attempt, I'm pretty sure this question pertains to Archimedes principle I calculated the...

Hello, I am doing simulation using Finite element for the concrete ,this I found the concrete model for the concrete in euro code as attached in the picture. But what I don't understand is basically why the peak of the curve is not the Fck (compressive strength), because the curve maximum is...

Author: Ronald Graham, Donald Knuth, Oren Patashnik Title: Concrete Mathematics: A Foundation for Computer Science Amazon link: https://www.amazon.com/dp/0201558025/?tag=pfamazon01-20 Prerequisities: Calculus Level: Undergrad

So this is my idea: make concrete using iron sand, preferably one with a decent ferromagnetic interaction. As the concrete sets, apply a magnetic field. The ferromagnetic particles align to the field creating a structure within the concrete. Possible to coat the iron sand in a retarding...

Hi guys, litterely just signed up today and am liking the site. Ill cut to the chase. I am designing a concrete barrier to resist explosions, ballistics and heavy impact. Now while I am still an apprentice at structural engineering, My knowledge in mechanics and general physics isn't...

Homework Statement A pick up truck is traveling at 58 km/h on a dry horizontal concrete surface when the driver applies the brakes locking the wheels. (a) How far does the car travel before coming to rest? (b) How long does it take the car to stop after the driver applies the brakes? (c) How...

Hi, Supposed the ground floor of a building needs to be raised 2 feet higher with respect to street level. How good is using broken concrete as fill versus putting soil? I heard one needs to compact the broken concrete. What do they exactly do when they compact it? Would the overall cost be...

Homework Statement a concrete column, 4.5m long, is reinforced with steel bars and carries a compressive load of 58 tonnes. The overall cross-sectional area of the column is 0.1m squared and the steel reinforcement accounts for 5 percent of this area. take young's modulus for steel as 200 GN/m...

Without using ' opposite charges of matter' explanation as a foundation for defining anti-matter, I wonder if anyone can present a more direct definition and examples.

Can anyone Help? "impacting concrete with steel projectile" Dear all gentlemen , Can anyone help me ? I'am doing my thesis in civil engineering in studying and mixing statistics with civil engineering with topic of " impacting concrete with steel projectile " if we consider the...

As we know that concrete is an insulator, but if I apply extremely high voltage through this concrete at a certain level, the concrete's property may become semi-conductor. In this way, will it be possible to magnetize a concrete wall using an extremely high voltage in this way? Does anyone...

hello everyone i have to design a simple two floor office building with roof. i am very lost and confused and don't know where to start from. can someone help?pleaseeee

I saw in some building constructions where they pour concrete in half of the horizonal beam (with rebar skeleton). Then the next day, they pour the other half of the rebar skeleton. This means the center of the concrete is not contniuous and only the rebars in the mid position holds the...

hi, this is a sample question.. I'm having trouble with part a) google has led me to believe that the equation i need for factored moment resistance is Mr = fr*As*fy (d - a / 2) fr is the factor, and i think it's .85 for reinforced steel according to those CSA guides As is the...

I will install a sump pump liner and will dig a hole near a stone wall foundation. My concern is that the hole might weaken the foundation a bit. I have insurance for such things but want to take no chances. If I back fill the space around the sump pump liner with concrete then any effects of...

Homework Statement Let X = R2 with the Euclidean metric and let S = {(x1, x2) : x1^2+x2^2 <1}.Prove that Closure of S ={(x1,x2):x1^2+x2^2<= 1} and that the Boundary of S= { (x1, x2) : x1^2 +x2 ^2=1 } . Homework Equations The Attempt at a Solution I was able to prove all my...

Hi there, I could really do with some help with this. First of all, this is NOT a homework question. It is a question that is listed in Benham & Crawford’s 'Mechanics of Engineering Materials' book. I am just reading through my books again and I'm stuck on this problem. As the book is...

Homework Statement I have to design the formwork system for an octagonal bridge pier similar to the type shown below, plus a headstock. http://img577.imageshack.us/img577/5743/prexconcretebridgecolum.jpg Homework Equations The Attempt at a Solution I can use any system I...

"Concrete" non-measurable sets I've had Vitali's proof of the existence of non-(Lebesgue) measurable sets branded into the side of my brain over the years. However, the proof always critically relies on evoking the axiom of choice. Has anybody every demonstrated a non-AoC construction of a...

Hello all. I was hoping someone could help me. I am building a storage loft in my garage. The issue that one side is drywall and metal studs. I was thinking that I would attach joist hangers to the concrete wall, then another set into the drywall wall but I wanted to know if the joist hangers...

a beam with an effective span of 8.2m is required to carry uniformly disributed loading of gk = 12 kNm-1(in additon to its own self weight) and qk = 10kNm-1. design a suiable reinforced concrete beam using strength class C30 concrete and high yield reinforcement could somone check my...

The following excerpt is taken from a Swiss Federal Nuclear Safety Inspectorate (HSK) publication[1]: “In the year 1988 a large scale crash test was performed at the US Sandia National Laboratory in which a Phantom military jet with a weight of 19 tons was impacted at a velocity of 774 km/h...

Homework Statement We were given many different slab sizes, shapes etc and asked to analyse them using Work = Energy equilibrium checks to find q, the maximum load per m^2 the slab can take. The first part was to show the fracture lines to use for analysis but I am stuck on one of them. I have...

Homework Statement A highway is made of concrete slabs that are 15 m long at 20.0°C. (a) If the temperature range at the location of the highway is from -20.0°C to +40.0°C, what size expansion gap should be left (at 20.0°C) to prevent buckling of the highway? (b) How large are the gaps at...

http://www.foxnews.com/scitech/2011/03/05/exclusive-nasa-scientists-claims-evidence-alien-life-meteorite/". Snippet:

A discussion arose tonight about why spacers aren't used in the foundations in houses, as opposed to sidewalks where there are gaps every few feet to allow for thermal expansion. Some possible answers were that the foundation would be more constant temperature, or that the concrete was somehow...

Hey everyone! Got an interesting problem here, I am thinking I did it correctly but I wanted to see your opinions. Here is the problem.. A 0.2-m-thick plane wall is constructed of concrete. At steady state, the energy transfer by conduction through the wall is 0.15 kW/m2. The inside...

Homework Statement How thick a concrete wall would be needed to give the same insulating value as 3.5 inches of fiberglass? Homework Equations Q = -A·k·ΔT/Δx k = -Q·Δx/A·ΔT The Attempt at a Solution So here, k is equal to the insulating value, and since I want the insulating value...

Hello fellow nuclear engineers and physicists, Does anyone know how to just get the scattered dose from a surface like concrete using MCNP5? I'm doing a project for a shielding class and I need to compare scattered dose and direct (uncollided) dose for a point detector. The photons are coming...

Homework Statement In many locations, such as Lake Washington in Seattle, floating bridges are preferable to conventional bridges. Such a bridge can be constructed out of concrete pontoons, which are essentially concrete boxes filled with air, Styrofoam, or another extremely low-density...

Homework Statement Hi there, I have an exam coming up regarding reinforced concrete, the question is to be similar to the one in the attached brief. It shows all the variables and given data. I apologise as I have already posted this question elsewhere but I don't think I laid it out...

Hi all, I massively appreciate any help in advance. I have an exam coming up and am completely stumped on a question regarding reinforced concrete design. The teacher has told us the question is going to be similar to the example he has given us but hasn't gone through it with us. It is a...

In my reinforced concrete textbook, we only have formulas and procedures for rectangular, or webbed and flanged beams. What do I do if I have an irregular shaped beam? How do I calculate the reinforcement?

Hi ! So recently I came across this interesting phenomenon that you can break through a strong concrete wall pretty easily by weakening it with certain holes drilled through it, following Hooke's law. I had heard about it before, but have never really thought about it. But now that I am, I...

I need help answering this question. So there's a slab beam and column layout of a reinforced concrete structure. Beam dimensions for all beams are as follows b = 250mm and h= 400mm (i) Determine the maximum ultimate limit state bending moment for beam b9 (it spans 6m) (ii) From first...

Hi All, my first post on this fantastic forum. I am attaching a timber ledger to a concrete pool with 10mm stainless-steel threaded rods at 900mm centres. I am using a polyester adhesive made by ramset to anchor the rods into the concrete. The adhesive instructions call for the rod to be...

Hi there, I was wondering if [PLAIN]"www.xiameter.com/en/ExploreSilicones/Silicone-Fluids/Pages/polydimethylsiloxane-fluids.aspx"[/URL] can be used to seal concrete?

OK, first things first, I am not a university student in math, or anything. I am actually still in high school. I am very interested in math, even, say, too interested for my level :) Well, yesterday I learned, on the internet, about the imaginary number i (Being \sqrt{-1}) and I read about it...

can anyone give me a problem and exercise about the methode dreux of Concrete i want to practice it as well before the exam come up?

My first message with P.P. Please be understanding. We are manually breaking a large concrete slab and I would be interested to know, roughly, what weight would be applied on impact by a sledge hammer weighing 14 pounds (6.4kg) traveling down at, say, 50mph (22m/s). Assume that the slab is on...

hey ppl, In a nutshell, need to come up with a 10mX2m foot bridge over a river made from steel and concrete also to include foundation design. borehole data are as follows. Depth. Description 0.2M Topsoil 2.60M...