Reinforced Concrete Walls - Yahoo Voices

They are bulletproof. Basement Retaining Walls

0.8 for walls with either top or bottom restrained against rotation;

Building Code Requirements for Structural Concrete, ACIhttp://playerforge.de/knottygrange9394/blog/296857/ 318, American Concrete Institute, P.O. In thiscase Ag = 12 in. ? min, walls, H.S. And as long as we keep the load(s) centered in the wall. ? min. .But we can also construct other types of basement walls (lesson here) with the Chapter 14 minimumamounts, as long as we don't require the wall to span too great of distances as it retains earthbackfill and thus resists the lateral earth pressures.

P nw = the `nominal' (theoretical, perfect world') compressive strength of the wall;

Sometimes you might hear me say "UBC Walls" ... f 'c = the specified 28-day compressive strength ofthe concrete;

In the context of this lesson, and a good portion of the course, when I say (just) `wall' I am referringto a reinforced concrete wall with the minimum reinforcement specified in Chapter 14 of the ACI318 Code. that the wall is hugely strong. here.

The axial compressive strength of a reinforced concrete wall is given by the following equation(subject to the limitations following the equation):

... ? min. In this lesson we will look at `just how strong' are reinforced concrete walls.

Draft - Comments Welcome

8. = 0.0025 for H.S. 14 of the ACI 318 Code (prescriptively) requires that there be 2 # 5 bars aroundall (window and door) openings. as is the area of a single bar,

0.55 = a number (that we may or may not talk more about later);

and,

By analysis it can be shown that walls with the `minimum reinforcement' described above are alsocapable of resisting significant lateral loads, and as such, may be used as basement retaining walls.(Well, maybe I have also said that about other materials.) Reinforced concrete walls are strong. andwhat I am referring to are (these) walls with the ACI Ch. thick (7-1/2 in. amounts of steel.

Here goes ...

where,

1.0 for walls unrestrained against rotation at both ends; and

... past the opening corners.

Limitations ...

or

6. (See ACI 318 Sec. And there is the case where we may building (`hide') a column in a wall, and assuch require more reinforcement.

... = 0.0020 for # 5 and smaller, Grade 60 or higher rebar

Ch. s = bar spacing, and

. 60):

7. ? = as / (s h) ...

(And where thus ... is the `factored strength'.)

where,

... Openings

... Introduction

h = wall thickness;

... ... k is kind of an effective length (height) factor, as follows:

5. (See the lesson on Basement Walls ... times h. = 0.0012 for # 5 and smaller, Grade 60 or higherrebar

2.0 for walls not braced against lateral translation.

And I tend to space basement wall reinforcement not greater than the above, though sometimes Ifeel somewhat alone in that practice.

Walls. Layers of Reinforcement

... looks like it accounts for slenderness and reduces the strength to account for potential buckling ofthe wall.

The ACI Code also specifies a maximum spacing of horizontal and vertical bars of the lesser of:

... In these cases where the wall is subject to flexural loading we may need more reinforcement. Withsome insulation (say an ICF system) they have great thermal properties. 18 in.

Design of Concrete Basement Walls, Jeff Filler, Associated Content.

Also, if the concrete above an opening acts as a lintel, or header, additional reinforcement may benecessary. 14 min. If I build my next house it will be out of concrete. Minimum Reinforcement

lc = is the wall height (height between support or brace points);

We are going to see that if we load the wall axially (in the plane of the wall) ... [1 - (k lc / 32 h)2] ... ?P nw ... Example: So, How Strong is Strong?

... thick for exterior basement and foundation walls).

2. (Lintel design will be in a later lesson.)

... And that these bars shall extend at least 24 in. three times the wall thickness,

Axial Strength of a Reinforced Concrete Wall, Jeff Filler, Associated Content

Design of a One-Way Reinforced Concrete Basement Retaining Wall, Jeff Filler, Associated Content.

The ACI 318 Code also requires for walls greater than 10 in. References

3. Once the loads get (way) off-center, or if we load the wall laterally (all or some component of theloads perpendicular to the plane of the wall), then the wall is loaded in flexure (bending) and it mustact as a one-way slab, beam, or two-way slab. In some cases we will need more than the minimumreinforcement specified by Chapter 14, such as what I call the `one-way' basement retaining wall(here). = 0.0015 for V.S.

4. Maximum Spacing

Other rebar (# 6 and larger or less than Gr. ? P nw = 0.55 ? f 'c Ag [1 - (k lc / 32 h)2], ...

Note: if we are using the wall to resist a `line load' then we generally deal on a `per foot of wall'basis. ? min, walls, V.S. 14.3.4).

I love this next equation (though I seldom have to use it).

These ratios are based on gross area;

The resultant of the axial load acts in the middle third of the wall.

The above equation may only be used under the following conditions:

... Box 9094, Farmington hills, Michigan, 48333.

The wall thickness may not be less than 1/25th the wall length or height; nor may it be less than 4 in.

For an example, let's go back to the lesson on Calculated Footing Width (here), except that let'splace a basement under the structure in the example. and ... b times h ...

... ? = strength reduction factor; in this application = 0.70;

Ag = the gross area ... h = wall thickness.

Calculated Footing Width for a Residential Foundation, Jeff Filler, Associated Content.

... here).

1. The number crunching is ... The most common type of such axial loading is the use of a (vertical)wall to carry (downward) gravity loads, say from roof, floors, decks, and the weight of the wall itself.If we are using the wall to resist concentrated loads, say reaction from a girder, or from joists, or aconcentrated load from a column (or something) above, the length of wall to be used may not exceedthe center-to-center spacing of the loads nor the bearing width of the load plus four times the wallthickness.

... Wall Strength

9. Reinforced concrete walls are cool. thick (except basement walls) that the reinforcement beplaced in two mats or layers parallel with the wall faces