Concrete Definition and 143 Threads

When we calculate the stresses in the section of a Reinforced Concrete column reinfored with Steel Rods, it is seen that the percentage Load carried by the Steel is much greater than the percentage area it contributes in the cross sectional area of the reinforced concrete section. The load...

Would it be possible to break concrete into rubble with sound? if so, How much energy would it take? Forgive me if this is a stupid question, I am not a physics guy but am trying to learn. Joe

Hi all, I am trying to calculate by hand the maximum load that a concrete 1m x 1m x 1m block can take before failing. The load is applied uniformly across the top of the block. I've found out that the average compressive strength of concrete is 70 MPa. Is there a formula that makes use...

a concrete block weighing 20,000 lb is supported by 2 STEEL rods, rod AB has an area of 1 in and rod CD has an area of 2 in... what is the elongation of each rod...? http://s44.photobucket.com/albums/f46/maximus11373/?action=view&current=untitled.jpg&newest=1i don't know how to start, should i...

Hey, sorry this isn't really a homework question, wasn't too sure where to put it. At the moment I'm taking a concrete structures course. I ordered the textbook online but it's not here yet. I have an assignment due on friday, and really need somewhere to start. So my question is: Does...

I'm inputing data into a SolidWorks material profile, but I'm having difficulty determining the value of the elastic modulus (psi) of steel reinforced concrete i'm looking at the following source for material properties: http://www.fhwa.dot.gov/pavement/pccp/pubs/05081/chapt3.cfm [for...

Homework Statement A highway is made of concrete slabs that are 15 m long at 20.0 degrees Celsius. (a) If the temperature range at the location of the highway is from -20.0degrees Celsius to +40.0degrees Celsius, what size expansion gap should be left (at 20.0degrees Celsius) to prevent...

Homework Statement As quoted from the question sheet: When building a tall support, often the self weight of the support must be considered. For an optimal support, the volume of material, and hence the cost, will be a minimum. If the maximum allowable stress in concrete is 12 MPa, determine...

Homework Statement A concrete beam my fail by shear or flexure. The failure probability in shear is equal to the failure probability in flexure, and the probability of failure in shear when the beam is loaded beyond is flexure capacity (ie, it has already failed in flexure) is 80%. Find the...

Hi I've just been reading some material and where it is mentioned that numbers are a figment of our imagination. They are not real and do not exist. But is there a time when numbers do?

Hello. I've just found this forum as I am looking for an answer to a question. For what it's worth, by way of introduction, I am a software and telephony engineer, with interests in aviation, boat design, and energy-efficient houses. I also write when I can. Here's my question. Plenty...

My cat has been licking the mortar on the fireplace for weeks. Today, he put up the fight of his life to go outside, so he was out on a leash most of the day and licking the concrete. Concrete has lime & sea shells, so I'm wondering what he's needing..calcium? Lime? He doesn't seem to be...

These braces were installed on the concrete support pillers at ground level of a very large 6 level mall. Would the engineers comment on the safety of this construction, in particular drilling through the concrete support structure

I'm studying the Franck-Hertz experiment for my Quantum Physics class, and I don't see why the minimums for the graphic U_1 (accelerating voltage) vs I_a (collector intensity) increase. It seems logical, but I can't find a proper explanation. If anyone could help me it would be great :)...

Homework Statement I am working on a physics project about karate, and I want to know how fast I would have to punch to break a practice concrete slab. I know that the slab requires 1900 Newtons to break. I also know that my arm has an approximate mass of 8.4 kg. I also know that my arm is...

Hi I have tried this question and am struggling to work it out; A concrete concrete tunnel with 2m x 2m dimensions on the outside (in cross section) with a uniform wall thickness of 200mm, is used to support a live load of 4kN/m^2 on its top surface. The density of the concrete is 25kN/m^3...

I woke up this morning to find a strong smell of sewer gas in our basement. The smell is gone now. However, I do not know where the exact source is coming from. We had this same issue before with one of the pipes in our basement that runs through the floor and connects to the outgoing...

Is it useful to build my own engine block from concrete , liners inside. Concrete is cheap , high resistant to pressure and high heat . Best regards , Mustafa Umut Sarac Istanbul

Hubbard's & Hubbards "Concrete To Abstract" Function On page 215 of H&H Vector Calculus, Linear algebra and Differential Forms text the authors define something they call the "concrete to abstract function". It is defined as follows: Let (x_1, ..., x_m) be a point in R^m and let {v_1, ...

Homework Statement Hello! I got few questions, about limits. º \lim_{x \rightarrow 0}(\frac{sin(x)}{x})=1 If I take values for x close to zero I get: f(x)=sinx/x f(0.1)=0.017453283 f(0.01)=0.017453292 as I can see it is not even close to 1. What is the problem? Where I am doing wrong? º...

Homework Statement hello I have to make a concrete base in metres cubed total 1.68 metres cubed. The ratio to concrete is 1 part cement to 2 parts sand and 3 parts gravel. how much cement,gravel, and sand in kilograms? Homework Equations ? The Attempt at a Solution ?

Much of the physics in 'Beyond the Standard Model' use a lot of abstract mathematics. So I was just wondering is doing this type of physics a unique way of doing concrete abstract maths, if that makes any sense? In other words being able to do abstract maths in a very concrete manner. Have a...

Hey guys, was just wondering if you could help me with re-inforced concrete. I am confused as to where to put the steel bars. I no that it needs to be placed in the part of the concrete that is under tension, but i can never find which part is under tension. An explanation would be good while...

Homework Statement Concrete highway slabs are poured in lengths of 10.0 m. How wide should the expansion gaps between the slabs be at a temperature of 20 degrees C to ensure that there will be no contact between adjacent slabs over a temperature range of -24 C to 45 C? Homework...

Two-thirds of the weight of a 1500 kg car rests on the drive wheels. What is the maximum acceleration of this car on a concrete surface? (2/3) * 1500kg =1000kg but I need the force so I can find the acceleration. What do I do next?

Homework Statement A cylin drical con crete sil o is 4m in diameter and 30m high. it consists of a 6000kg concreet base and a 38000kg concrete cylindrical concreete walls. locate the center of mass of the silo (A) when it's empty and (B) when it is two thrids full of silage whose density is...

Are Pyramids Made Out Of Concrete, as Joseph Davidovits claimed? This page on wikipedia: http://en.wikipedia.org/wiki/Joseph_Davidovits presents a short bio of Davidovits and his theory about how pyramids were built. According to this theory, the ancient Egyptians would have used a...

Homework Statement I need to find the approximate terminal velocity of a baseball shaped concrete sphere and what distance it would take to reach that terminal velocity if dropped on Earth under normal weather conditions. I have found that a baseball made of concrete would have a mass of...

I'm giving a talk entitiled "concrete analogies of abstract concepts", where I give examples of concepts in mathematics that might have arisen in things found in every day life. I already have "chess" for isomorphism and "acronyms" for homomorphisms, but I'm running a bit dry. Anyone got any ideas?

hi just a quick question,having done materials labs we came up with a figure of 275.8kN for the compression strength of a cube of concrete acting over an area of 150mm x 150mm. i want to convert this compressive strength to the standard N/mm^2 units.To do this i multiplied 275.8 * 1000 and...

Hi there, I'm just curious as to how to determine the moisture content of some concrete we've recently set. I was hoping I could just use an Ohm meter to, set the probes say 1cm apart and have some kind of table that corresponds to xxx resistance = xxx % moisture content. Anyone have any...

A concrete column has a diameter of 350mm and a length of 2m. If the density (mass/volume) of concrete is 2.45\frac{Mg}{m^3}. determine the weight of the column in pounds The answer to this problem is given as 1.04 kip not pounds like the question ask for, but that is not my problem. This...

Hi! I'm having some difficulty trying to clear some things when designing r.concrete slab and beam. My question is : when do you reduce moment ? I am aware we reduce moment over support...but when that support is in middle of beam .(continuous beam) For simply supported beam we don't make...

Homework Statement Two concrete spans of a L = 270 m long bridge are placed end to end so that no room is allowed for expansion (Fig. P10.55a). If the temperature increases by T = 21.0°C, what is the height y to which the spans rise when they buckle (Fig. P10.55b) Homework...

How much kinetic energy or momentum would an object need to penetrate 9 feet of heavy grade reinforced concrete?

Help with Heat Conduction Question My question is: These days they reinforce concrete walls with steel bars. Would the steel bars enhance or degrade the insulating value of the concrete wall? Explain? Metal is a good conductor and concrete is a good insulator. My answer so far is that it...

dear engineers i have to complete a project within next 10 days about electromagnetic waves and i need some information about the electrical properties of concrete and how can it affect on waves when trying to penetrate it ( i need the permittivitty and permeability of concrete and others...

Does anyone know of any way to measure the natural frequency of concrete? Any input would be extremely helpful, even if the method does require sophisticated technology or machinery :smile:

A Porsche 944 Turbo has a rated power of 217 hp and a mass, with the driver, of 1460 kg. Two-thirds of the car's weight is over the drive wheels. What is the maximum acceleration of the Porsche on a concrete surface where static friction=1.0 1hp=476watts 217hp=103292 watts and power=...

I'm debating between ettringite and calcium hydroxide...ettringite is responsible for expansion in volume during a sulfate attack while calcium hydroxide affects the durability of concrete...any ideas?

Pretty straightforward, right? I want some definitions for "abstract" and "concrete". If anyone is interested in doing some reading, here are some links: 1, 2, 3, 4, 5(PDF), http://64.233.187.104/search?q=cache:AUWz3yToePIJ:www.hcrc.ed.ac.uk/cogsci2001/pdf-files/1106.pdf . I see a connection...

Here it is: A 2000-kg car traveling at 85.0 km/h crashes into a concrete wall that does not give at all. Estimate the time of the collision, assuming that the center of the car travels halfway to the wall with constant deceleration. (Use 5.75 m for the length of the car.) I know I need to...

Hello, I have a friend that would like to put a pool in his livign room but is concerned about the weight of the pool...he lives in an apartment building so in between each floor it's concrete the pool holds 705 gallons (2680 litres) and its diameter is 9 feet and the water will be 21 inches...