Why ACI recommand number of layers in one lift concreting (in a dam block) must be even?
539867
The reason the layers are created are so that you don't have separation.\n\nThe reason that the layers are of a specific size is to prevent separation.\n\nThe reason each layer should be "even" is just so that the contractor can remember a single number, not multiple numbers.\n\nAlternate answer: you are misinterpreting ACI.
861916
I can't see the rest of your question, but even numbers can be multiples of three. Like 6 (2x3). They are not mutually exclusive.
883909
draw FBDs of the 2 blocks independently\nbe careful\nfind the accelrations of the  2 blocks using CONSTRAINT relations\nand comes ur answer\n\ndon't wait for the solution\nit lessens ur thinking power n creativity\n\nif it's still problematic, consult ur lecturer\n\nconcentrate on ur studies \nur still a college guy
154903
typically this is determined by the company making the admixtures.  If you do not have access to high range water reducers/superplasticizers then you are not going to make it happen without segregation and a w/cm ratio that will make it useless.\n\nAlso SCC is very dependent upon the gradation of the aggregates, it has much more in the way of fine aggregates than standard concrete mixes.\n\nHere's a rough example:\n780 pounds cement\n1300 pounds sand\n500 pounds 3/8" chips\n1000 pounds 3/4" nominal diameter aggregate\n36 gallons of water\n\nThe admixture dosages are going to be different depending upon the company making the chemicals.\n\nThis is rough and would end up with an overyield.  SCC is something that to be developed you need a lot of experience or a lot of test batches.  Also go to the Precast/Prestressed concrete institute website.  A while back they had a preliminary guide regardint SCC
911920
You need to determine the depth you need to go down by knowing the frost line in your area. Dig your trench a foot below the frost line, and pour a concrete footer that is at least 12" wide and 18" deep. Put #4 rebar in the footer, 4 bars, 2 at 3" off bottom of footer and 2" in from the outside edges, and 2 more bars at 3" from the top of the footer, above the lower bars. You'll also need some vertical rebar sticking up from the footer on 24" centers to fit into the cells of the block. On the corners, put vertical bar so you have a bar in the corner and the first cell after the corner on each side (3 bar corner).\nBuild your block wall after the concrete footer has cured. If you need to extend the vertical rebar you installed, use wire ties and overlap the joints by a minimum of 6". When the block wall is finished, pour the cells in the block with a grout mixture, or concrete mix with pea gravel.
432384
There are two typical means. The first (and oldest) is poured on site over a "rebar" type super structure. The second is made from "precast" sections that are delivered  and installed at the job site.
417256
If you have a shear wall, you need to design it according to chapter 11 of ACI 318. Your wall will obviously have some axial load, but shear due to wind or seismic will control. It's really not that hard to design it if you follow the examples in a good RC book. \nSince you have a  shear wall, then the rest of your structure just carries gravity loads, so effectively, it is common practice (and academically accepted) to design all the gravity load resisting system. And then, design the shear wall. You lateral loads do not affect the size or reinforcement of you beams and columns. Do make sure, however, that the shear walls (you better have at least one in each direction) are big enough that their stiffeness is a lot bigger than that of the columns. So, if you have for example 25 18" x 18" columns, but you wall is only 8" thick and 36" long then obviously, that's not a shear wall since the sum of your column stiffnesses is a lot bigger than the shear wall. PS I need some "best answer" points
354673
Well, you didn't say whether you're building a building, a bridge, a trestle, a tower, or other structure.  But you could start with some general articles, like this Wikipedia article, which has links to specific sites which give some specifications.\n\nThe other link gets properties for different I-beam sizes--I presume you understand the terminology well enough to read the resulting tables.
148864
If your trench silo looks like the ones that I am familiar with, it's rectangular when you look down on it and  has sloping sides and sloping ends. The way to compute its volume is to break it down into pieces that are regular prisms or pyramids. I would break it down like this:\n\nStarting with the flat rectangular bottom, extend the edges of the rectangle to the boundry of the silo. That will divide your silo into 9 pieces.\n\nThe center section with a flat bottom is a rectanguar box.\n\nThe 4 corner pieces that slope in two dirctions. They are pyramids.\n\nThe 4 pieces sloping sides, two that lie along the long side of the rectangular box and two at the ends,  are triagular prisms.\n\nOf course, some of those silos get mounded up in the middle, so that adds another dimension to solving the problem.\n\nYours for better silage,\nGuru
151606
if all the lines are equal in every way (duplicate) then you can put a measurment (dimension) from the existing line to a datum or border whichever you choose and then put a callout like 3@12.00' (3 lines at 12.00 feet)in the dimensionwith a arrow pointing at the line.\n\njeff
450313
10 percoset should do the trick\nThis is a joke....just in case you are dumb enough to try it.lol
260483
Not know 6, but, it helps give a design structure, I feel. It like a Blue Print for a house, easy to change before the house is built. Flow chart works the same way.
459721
How thick do you want the layer? when you find out, are you going to do it?\nNO??????\nSo, why are you asking??????
349930
it's because of elasticity(bulk modulus).The force on the surface will try to reduce the volume and but as the volume changes, there is a net upward force and an eqilibrium will be reached when outward (volume)elastic force equals the downward cohesive force. But the decrease in volume and hence the level of warer is so small(in the order of micrometre) that we don't notice it.
226597
Well this mite be a job. The number is on the back of the block where the bell housing for the trans bolts to the block.\nDont know what this number will help you or not, but that is where it is.
720952
Hardened concrete strength depends on the water to cement ratio (w/c ratio). Lower the w/c ratio, higher the concrete strength. This is because excessive water in concrete may create water pores and void in the concrete which will affect concrete strength.\n\nBut the problem is when we use lower w/c ratio, workability of the concrete will be very poor. Increasing the use of water in other hand may improve workability but increases w/c ratio. By adding superplasticizers into fresh concrete, it can improve workability and maintain optimum w/c ratio.\n\nAlthough plasticizers cannot directly improve the strength of hardened concrete, it promotes workability, thus enable concrete to have lower w/c ratio.\n\nMore technically, superplasticizers interact with wet cement particles and produces a membrane of absorbed charged molecules around each particles, with prevent the cement from flocculate or become sticky.
943880
One strand for every foot, so 6 strands should do it.........:)