US1472917A - Precast reenforced concrete construction - Google Patents

Description

Nov 6 1923.

A. N. LAIRD PREGAST REENFORCED CONCRETE CONSTRUCTION Filed Nov, 8, 1922 5 Sheets-Sheet 1 Nov. 6 1923. 1,,47291? A. N. LAERD PRECAST REENFORCED CONCRETE CONSTRUCTION Filed Nov. 8. 1922 3 Sheets-Sheet 2 l n l cm {MENU-mum- 1 l M 5 4 w mpmwr:

Nov. s, 3923. nmzmi N. LAIRD PRECAST REENFORCED CONCRETE CONSTRUCTION Filed Nov. 8, 1.922 3 Sheets-Sheet 5 l'f gifi,

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Patented Nov. 6, i923.

UNHTED STATES,

ALBERT NORMAN LAIRD. OF DETROIT, MICHIGAN.

PRECAST REENFORCED CONCRETE CONSTRUCTION.

Application filed November To all whom it may concern:

Be it known that I, ALBERT NORMAN IJAIRD, a citizen of the United States, residing in the city of Detroit, in the county of \Vayne and State of Michigan, have invented an Im rovement in Precast Reenforced Concrete onstructions, of which the following, in connection with the accompanying drawings, in which like characters on the drawings represent like parts, is a specification.

The invention to be hereinafter described relates to precast reenforced concrete constructions consisting principally of four specially shaped members, together with connecting means, adapted by combination thereof more especially for constructing retaining walls for railroads, but may equally well be used for walls or cribbing of any form or character{ Thisinvention aims to do away with the expensive, slow, and difficult process of mixing concrete at the location of the work and the depositing of the'concrete mixture between forms, by providing for the precasting of the concrete units or members at a central manufacturing plant, and then conveying same to the locality where needed and thereeasily assembled and built as desired, and the spaces filled around the members with 'tamped earth or other filling material as the members are placed.

Another object of my invention is to provide members whereby straight or'curved retaining walls, or walls with angles in their faces in either direction and of any angle of bend may be constructed, and designed in any of these constructions to resist all horizontal components of the pressure, which would be exerted by the material filled in and tamped in place as the layers are placed, as well as the horizontal component of the pressure exerted by any superimposed load on the filling material; the vertical weight of the earth or load is not intended to be supported directl by the cribbing members, but is supported y the material which is filled in behind the wall.

A further object of the'invention is to provide Y shaped spread arms integral with the header member for anchorage purposes. thereby eliminating the necessity of tying the header member to another member to provide an anchor as in the box type of cribbing, since the 45 spread arms of the header member themselves form that anchor Serial No. 599,653.

with a maximum of efficiency as the maximum amount of filling would have to be displaced before the header members would move.

An additional object of my invention is to provide double ended header members with Y shaped spread arms on both ends adapted for use in construction of double faced retaining walls, in combination with the other members.

Another object of my invention is to provide a positive connection between the stretcher and header members absolutely preventing the displacement of any piece or member and thereby increasing the facility of laying up the construction, since there is a definite place provided by each member laid for the next succeeding member.

A further object of this invention is to provide means for connecting the header members to alternate rows of stretcher members, and likewise the stretcher members are connected to alternate rows of header members, and thereby being interconnected the structure more nearly becomes a unit.

Various forms of construction may be made in accordance with the invention and within the scope thereof such as shortening the headers resulting in the rear wall being stepped up.

Other objects'and uses will be noted and explained in the specifications and illustrated in the views shown in the accompanying drawings, in which-- Figure 1 is an isometric view embodying the various principal parts of the invention- Fig. 2 is a top view of the stretcher or face block mem'ber showing reinforcing bars in dotted lines.

Fig. 3 is a side elevation view of the stretcher.

Fi 4 is a top view of the header or tie inem er showing reinforcing bars in dotted mes.

Fig.5 is a side elevation view of the header.

Fig. 6 is an elevation view of the coping,

Fig. 8 is a top view of a wa 1 construction showing how an angle is made.

ended header. member.

Fig. 12 is a sectional view of wall construction using double ended headers, showing partial construction of a double faced retaining wall.

Fig. 13 isa top view showing the alternate placing of stretcher and header mem-- bers.

Fig. 14 is an elevation view of part of a wall.

Fig. 15 is a section of a completed retaining wall showing railroad tie and one rail of track on the filling placed between the various members of the construction.

Fig. 16 is a detailed top view showing method of forming a wall with a right angle corner.

Fig. 17 is a detailed top view showing method of forming a wall with an external right angle corner.

Fig. 18 is a top view of a half-stretcher member used in the construction of corners and turns. I

Fig. 19 is an elevation view of the halfstretcher member.

Referring to the drawings the construction shown is the preferred form of the invention, and consists in the proper combination of the various precast reenforced concrete members, best shown in Figs. 1, 9 and 15, which members may be of any appropriate size as to length, breadth and thickness, which would be determined by the type of construction desired and the forces which are to act upon the completed structure. For example for ordinary railroad use headers 3 with Y arms would be about 8 feet in length, 4 inches in breadth and 8 inches in thickness with head end 9x10 inches, and other members in proportion.

,In Fig. 2 stretcher or face block 1 is shown with reinforcing bars 6 in dotted lines, which reinforcement is necessary to withstand the tension and shear developed in the block under load or in handling. Rear projections 7 of stretcher 1 are constructed integral therewith at each end and are provided with slotted holes for the purpose of making connection with header member 3 hereinafter fully described. Each rear projection 7 with slotted hole shown at 1' is so located that connecting bar 9 provided on header member 3 will fit therein, and is slotted so as to give ufiicient play for prac tical purposes. At each end of stretcher 1, the points of hearing are shown at 1" Fig. 3. Stretcher 1 is cut up as shown at 8, Figs. 1

and 14 to insure a more perfect bearing. This cut up may be small or large and a practical advantage is to provide a means for drainage, or if desired may be entirely eliminated and other means for dr-alnage provided. I

In special instances a metal lug or connecting bar 9 may be substituted for the hole shown at 1' to provide direct connection between the alternate rows of stretchers. This is especially applicable to corner construction as shown in Figs. 1, 16 and 17. Exposed edges of stretcher 1 as well as the exposed edges of other concrete members are bevelled or chamfered as shown at 10, Fig. 1, to prevent chipping and to improve the appearance of the completed wall. Half stretcher 2, Figs. 18 and 19, is similarly constructed of reenforced concrete as stretcher 1 with th exception that .it is provided with only one rear projection 7 with a hole therein shown at, 2*, the other end being provided with a holeshown at 2", through which connecting metal lugs or bars 9 are placed when the members are assembled. The points of hearing are shown at 2, Fig. 19 at both ends of half stretcher 2. Half stretcher 2 is used in the construction of corners or bends.

Header or tie member 3, Figs. 4 and 5 is constructed also of precast concrete reenforced with steel preferably to resist the tension and to prevent breaking in handling. One end is provided with holes shown at 3 through which bars or lugs 9 are projected, said bars 9 fitting when the-members are assembled into slots or holes at 1 provided on stretcher 1 and into similar holes at 2 and 2 on half stretcher 2, best shown in Figs. 1 and 13. The other end of header member 3 is constructed of two arms 3 integral therewith projecting at an angle in the form of a Y preferably at 45 to the main line of member 3. Each spread arm 3 is provided with a hole shown at 3" and 3 in which metal bars 9'are inserted when assembling the construction. The purpose and use of header member 3 is to form a secure anchor back into the earth which is filled around the members and tamped as the construction proceeds and thus preventing the completed wall shown in- Fig, 15 from being forced out of .alignment due to the weightof the earth or the filling material 12, Fig. 15, or due to any superimposed load on the completed structure such as a railroad track shown at 11, Fig. 15, or any train or engine thereon. Arms 3 areso arranged that in straight wall' construction the rear ends of alternate layers of headers 3 bear on each other at points around 3 and wall in alignment and of maintaining the batter or slope of the face of the wall. It also makes it impossible for any one section of the .wall to be forced out of alignment without moving the whole section, or in other words the wall construction is securely anchored member to member. The 45 angle of spread of arms 3, Fig. 4, .insures that the efficiency of the anchor member is a. maximum service, since the maximum amount of filling material would have to be displaced before the header member 3' would move.

Sub-header member, or more properl double ended header 4, Figs. 9, 10, 11, and 12 is similar in construction to header member 3, except that it has spread arms 4* at both ends. Double ended header 4 is used as a still further tie or anchor back into the earth filling, and is used in special case of very high or very heavily loaded wall sections. It is also especially used as a means of constructing a. double faced wall Figs. 9 and 12. A wall of this type could only fail if the members themselves pull apart, and therefore a double faced wall of thistype is for all practicable purposes as strong as necessary' for any wall construction, and such a wall may be constructed in less time and at much less expense. and if it ever needs to be removed, it has practically 100% salvage value.

The coping block or finishing member 5, Figs. 6,7, 7, and 15 is constructed similarly to the other members of pre-cast reenforced concrete, and as its name indicates isplacedon top of the wall to improve its appearance. Coping block 5 is hollowed out to reduce its weight and is provided with holes or slots at 5 on each end into which bars 9 are inserted making appropriate connection. It will be noted by reference to Figs. 7 and 7 showing opposite ends of co ing block 5 that 'they are constructed slightly differently, because the two headers 3 to which the respective ends of coping block 5 are connected are at different heights, it being explained heretofore that the headers are laid alternatingly.

The method of constructing a wall with an angle is shown in Fig. 8, where it will be noted that half stretcher 2 provided with hole 2 is used and it is connected to stretcher 1 by'means of usual pin 9. Similar designs forconstructing walls with internal and external ri ht angle faces are shown in Figs. 16 and 1 in which the same members, i. e. stretcher 1. half stretcher 2. and header 3 are used as indicated; in fact the members described are capable when properly assembled of constructing any of the following: straight or curved retaining walls to support a fill; walls with angles in the face, in either direction and with any degree of bend; double faced walls; shore protection; docks;

gravity section dams; large bin constructions for storage purposes; wing walls for abutments of bridges with poured or cast in place concrete bridge seats; and bulkheads. .t will be noted that a wall constructed by use of members described is designed to resist all horizontal components of the pressure which would be exerted by the material which is filled in and tamped in place as the layers are placed, or the horizontal component of the pressure exertedby any superimposed load on the filling material. If no Wall were built the forces acting would cause the earth to spread out until it reached the angle of repose, and the bank would then be stable against movement. The wall constructed by use of the members described resists the forces which tend to make the earth spread out nd retains it in the confines of the cribbing. The vertical load or weight of the earth is not intended to be supported directly by the cribbing members but it is supported by the material which is filled in behind the wall. The above mentioned horizontal pressure is exerted against the inside face of stretcher 1 which acts as a beam and transmits the total pressure so exerted to its ends where through the connecting means it is in turn transferred to the headers 3, and headers 3 in turn act to transmit the pressure back into the bank of earth to a point where it will combine with the vertical earth pressures and thence down through the filling material to the supporting soil or footing. Because of the position of header 3 and stretcher 1 in the Wall as shown in isometric view, Fig. 1, the front of header 3 is directly opposite the middle portion of stretcher 1. Header 3 does not exert any force against stretcher 1 at this point and since it covers a portion of stretcher 1 there can be no force exerted at this point due to the earth filling or to superimposed loads. Since a load exerted against the middle of the member causes the greatest stresses, the face of the wall is in reality much stronger on this account.

While the Y shaped header 3 is the preferred form, it might be varied within the scope of the claims. The face of stretcher 1 may be trowelled smooth, bush hammered, or given other special treatment in finishing. The construction of walls with ofi'sets, angles, bends, rear or front step-ups, etc., is possible with equal safety and no unusual difficulties or makeshifts.

All these members may be made in a central manufacturing plant in quantities required with appropriate reinforcing rods and connecting means, and then transported to the field of construction where they would be assembled without any special preparation of the site, and assembled as follows: Alternate stretchers and headers are laid, the headers beingfastened to the stretchers above and below them. The metal dowel pin or bar 9, which is the means of connection prevents any improper construction, and also prevents a side movement either during or after construction, and the parts can onl be fitted in one manner. After alternating the laying of stretchers 1 and headers 3 t0 the desired hei ht, coping members 5, Figs. 7 and 7, are tted to complete the wall. When double faced wall construction is desired double ended header 4 is.

- strong when constructed and is devoid of complicated parts.

It will be understood that the inventionis not limited to the specific construction shown herein, but that various deviations may be made therefrom without departin from the spirit and scope of the appende claims.

I am aware that precast reenforced concrete cribbing and wall construction in general is not new, such as the box forms and T t pe, but it will be noted that the novel Y eader 3 and double Y header 4, in combination with the stretcher and other members produce an improvement in retaining wall construction not heretofore used,

and with less members, consequently I do' not claim such a construction broadly, but having described my invention, what I do claim as new and desire to secure by Letters- Patent is 1. In a precast concrete construction, the combination of facing members, Y shaped header members and means for-connecting said facing members and said header members, substantially as described.

2. In a precast concrete construction, the

' combination of facing members with rear projecting ortions containing holes, and Y shaped hea or members with one end of each provided with projecting bars adapted for making connection with said facing members, said header members acting as anchors back into the earth filled around the members, substantially as described.

3. In a recast reenforced concrete construction, t e combination of stretcher members provided with two rear pro'ecting portions at end of each member an containing holes therein, half-stretcher members each with one rear projecting portion similarly provided with hole therein, the other end containing a slotted hole, said half-stretcher being used in constructing walls containing angles and bends, Y'shaped header members acting. as anchors one end of each being provided with opposite projecting bars adapted for makin connection by being inserted in slotted holes provided on said stretcher and half-stretcher members, and

means for appropriately connecting said members together.

4.111 a precast reenforced concrete construction, the combination of stretcher members provided with two rear projecting portions containing holes therein, half stretcher members each with one rear projecting portion containing a hole therein, the other end being also provided with a hole, said half stretcher being used in constructing walls with corners and bends, Y shaped header members acting as anchors in the earth, the heads of each being provided with bars projecting from to and bottom of head portion adapted and p aced for making connection wits said stretcher and half stretcher members, double ended header members consisting of a main portion from which branches at angle of project at both ends adapted for being laid between the Y shaped header members thereb providing secure anchorage for double aced wall construction, and

means for appropriately connecting saidmembers, substantially as and for the purpose described.

5. In a precast reenforced concrete construction a Y shaped member consisting of a main portion provided with a head at one end containing bars projecting from opposite sides thereof, an two branch portions at other end integral with said main portion and placed at an angle of 45 adapted for forming an anchorage in the earth, substantially as described.

6. In a precast reenforced concrete con: struction a double ended header member consisting of a main straight portion from which and integral therewith from each end thereof two straight branch portions extend at an angle of 45,"adapted for forming an anchorage in the earth, substantially as described.

In testimony whereof, I have signed my name, in the presence of two witnesses.

ALBERT NORMAN LAIRD.

Witnesses:

Wm. GLEN Hmom, RAY A. Wm.

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