EXAMPLES OF BsIN FOROED-CONCRETE BET•INING WALLS. 0. B. di Q. Standard. Fig. 121, page 531, shows the typical cross-section of the retaining wall employed by the Chicago, Bur lington and Quincy Railway in track elevation in Chicago.* The portion above the angle in the back is the same for all heights. Fig. 122, page 531, shows the method of constructing and brac ing the forms used in building the wall shown in Fig. 121. * A retaining wall having a sec tion similar to that in Fig. 121 has frequently been used. Notice that this type is really intermediate be tween a reinforced-concrete can tilever wall (Fig. 114, page 518, or Fig. 123, page 531) and a plain concrete wall (Fig. 116, page 527, or Fig. 118, page 528).
The forms are a combination of continuous and sectional. The sectional portion consists of two parts: (1) the studding for the face, and the forms for the coping and for the flat slope near the bottom; and (2) the form for the back of the wall. Ordinary sheeting is used on the face between the forms for the coping and for the flat slope at the bottom. No attempt was made to use sectional forms for the main part of the face, because the sections become battered and warped with use and do not fit well, and hence leave the wall rough.
Notice the method of bracing the forms, particularly the interior inclined tie rod.
Fig. 123 shows the cross section of the standard cantilever reinforced-concrete retaining wall designed by the company controlling the patent for the corru gated bar (§ 465) ; and Fig. 124 shows the standard design for a
counterforted wall by the same company.
Fig. 125, page 532, shows the cross section of a counterforted wall built by the City of Pittsburg, Pa. The foot ing is 24 inches thick, and the face wall 18 inches; the counterforts are 12 inches thick, and 10 feet apart center to center. The rein forcement in the floor is 11-inch plain round rods spaced about 7 inches apart; and the reinforcement in the face wall is plain round rods varying from inch at the bottom to 4 inch at the top of the wall, the spacing increasing from 3 inches at the bottom to 6 inches at the top. The rods are bent in such a way that at their ends next to the counterforts they are near the face of the wall, while in their middle portion they are near the back of the wall. The reinforce ment in the counterfort consists of plain round rods varying from 1
to 11 inches in diameter, connected to plates bedded in the floor
and in the curtain wall by pins through
forked ends. These anchor plates are
} inch thick and from 8 to 11 inches
wide, and have three lines of holes in
them, one for the rods in the
fort, and the two others for the rods
in the floor on each side of the
terfort. Two nuts are used on each
end of each rod in the floor and in
the face wall.