Patent Publication Number: US-3875710-A

Title: Structural system and method employed therein

Description:
United States Patent 11 1 Dawson et al.  
 1 STRUCTURAL SYSTEM AND METHOD EMPLOYED THEREIN [75] Inventors: William F. Dawson; Milo Shemie,  
 both of Montreal, Quebec, Canada [73] Assignee: Descon/Concordia Systems Ltd.,  
 New York, N.Y.  
  221 Filed: May 1, 1974 1211 Appl. No.: 465,924  
 Related U.S. Application Data [63] Substitute for Ser. No. 312,836, Dec. 7, 1972, abandoned, which is a continuation-in-part of Ser. No. 233,043, March 9, 1972, Pat. No. 3,775,928.  
 [52] US. Cl. 52/236; 52/285; 52/432; 52/582; 52/741 [51] Int. Cl E04b 1/35 [58] Field of Search 52/236, 167, 175, 285, 52/432, 741, 747, 584, 583, 582, 597, 593, 52/291 [56] References Cited UNlTED STATES PATENTS 2,178,097 10/1939 Davison et al. 52/223 R 2.920.475 1/1960 Graham 52/432 3,136,092 6/1964 Contini 52/175 X 3,372,519 3/1968 Russell 52/285 X 3,505,768 4/1970 Bentley 52/236 X 3,775,928 12/1973 Dawson et a1. 52/432 X FOREIGN PATENTS OR APPLlCATlONS 1,157,689 12/1957 France 52/285 6,715,813 10/1968 Netherlands 52/285 Primary Examiner-Price C. Faw, Jr. Attorney, Agent, or FirmHubbell, Cohen &amp; Stiefel [57] ABSTRACT A structural system and the method employed therein includes a building unit comprising at least a pair of spaced apart concret wall slabs which support a concrete floor slab thereon which is connected directly to the wall slabs by the use of bolting means and tie plates embedded in the wall and floor slabs. The end portions of the floor slab have recesses therein which 1451 Apr. 8, 1975 have tie plates either embedded in or extending across at least a portion thereof. The top portions of the wall slabs have tie plates protruding therefrom. The floor slab tie plate aperture and the wall slab tie plate aperture are substantially normal to each other and are directly connected together via an intermediate L- shaped connecting bracket. Adjacent building units in the structure share a common wall slab and the adjacent end portions of adjacent floor slabs associated therewith are directly connected to each other and to the common wall slab via intermediate L-shaped connection brackets, by aligning the apertures in the associated tie plates and connection brackets to form through holes, bolting means being connected therethrough. A plurality of floor slabs may be supported between a pair of common wall slabs in this arrangement with the end portions of the floor slabs connected thereto as above. Adjacent side portions of adjacent floor slabs in this arrangement have recesses therein which are in communication and which have flat plates having apertures therein extending thereacross. These adjacent side portions are connected to each other by connector plates having apertures therein which are aligned with the apertures in the flat plates to form through holes, a bolting means being connected therethrough. Concrete wall slabs normal to the floor supporting wall slabs may also be provided, such as along the longitudinal axis of the structure, to vertically transfer laterally applied loads such as shear transmitted across the floor slabs which are ultimately connected thereto. ln constructing a structure, supporting wall slabs are anchored to the wall or foundation below by bolting, floor slabs are placed thereon and aligned and adjacent side portions thereof directly connected together by bolting, and thereafter end portions thereof are directly connected to the supporting wall slabs by bolting. In this arrangement the direct interconnections between floor slabs and wall slabs are identical throughout the construction, except for end walls, as well as the wall slab to wall slab direct interconnections, via intermediate L-shaped connection brackets and bolting.  
 18 Claims, 25 Drawing Figures &#34;IBT JIG PATENTEDAPR 8:915  
  talull l r a N STRUCTURAL SYSTEM AND METHOD EMPLOYED THEREIN CROSS REFERENCE TO RELATED APPLICATIONS This application is a substitute application for our application entitled Structural System and bearing U.S. Ser. No. 312,836, filed Dec. 7, I972, now abandoned, which was a continuation-in-part of our application also entitled Structural System and bearing U.S. Ser. No. 233,043, filed Mar. 9, I972, now US. Pat. No. 3,775,928.  
 BACKGROUND OF THE INVENTION l. Field of the Invention The present invention relates to structural systems and methods of employing concrete slabs for both walls and floors in which the slabs are directly connected together.  
 DESCRIPTION OF THE PRIOR ART Prior art concrete building structures normally involve the use of a superstructure which is a composite structure made up of precast concrete and structural steel. Such structures are subject to progressive collapse in the event of local explosion or local damage to the structure as well as being susceptible to earthquake damage even at the lowest readings on the Richter scale. Although the structure is a composite structure, the various columns, walls and floors making up the structure tend to act substantially independently when subjected to applied loads due to earthquakes or local explosions as these structures are normally incapable of distributing such applied loads throughout the structure. Furthermore, such structural systems normally require the use of grouting during the erection process as well as the use of welding and, thus, the erection process is quite time consuming to allow for these procedures. Furthermore, the use of welding and grouting requires the utilization of highly skilled craftsman. In addition, since these structures require the use of grouting, such a structure may not be erected in all weather conditions resulting in the parennial construction problem of variations in environmental conditions affecting the amount of time required to complete a building structure. This highly seasonal restriction on construction is unsatisfactory.  
  As was previously mentioned, such prior art structures do not have sufficient resistance to wind and earthquake loads as their resistance to cumulative shear and overturning moments is unsatisfactory. In order to attempt to compensate for such low resistance, structures of this type must be considerably reinforced, particularly in high probability earthquake areas, at a considerably higher cost than the normal cost of construction of such a structure. As was also previously mentioned, such prior art structures are susceptible to progressive collapse. Furthermore, such prior art structures require the use of a multiplicity of building elements such as beams, columns, etc., as well as walls and floors, increasing both the time and cost of construction and minimizing the possibility of the material manufacturing process associated therewith being repetitive.  
  The inability of these prior art concrete structures to sufficiently resist both earthquake loads as well as local explosions and progressive collapse has resulted in time consuming and costly construction procedures such as the requirement of the use of temporary supporting frames during construction until the grout utilized with the associated joints has set. Thus, these prior art systerns which require the pouring in place, during erection, of a concrete grout to insure continuity and, incidentally, to prevent progressive collapse are not satisfactory, nor are such systems which require welded connnections to obtain continuity.  
  Some of these disadvantages of the prior art have been overcome by the construction method disclosed in our previous US. Pat. No. 3,775,928. However, as a result of further experimentation, we have developed the more presently preferred construction method and system of the present invention which overcomes these disadvantages of the prior art.  
 SUMMARY OF THE INVENTION A structural system and method employed therein is provided which includes a building unit which comprises at least a pair of opposed upstanding spaced apart concrete wall slabs which support at least one concrete floor slab thereon. In such a structural system arrangement, the floor slabs utilize a common connection scheme throughout their periphery comprising the end portions and the side portions thereof. Such floor slabs include a plurality of tie plates, having apertures therein, which are embedded in recesses in the floor slab side and end portions. The wall slabs in such a structural system, including those utilized as shear walls as well as those utilized as bearing or supporting walls, except for the end walls in the structure and where there is no wall to wall interconnection, utilize a common connection scheme for interconnnection of adjacent wall slabs to each other and to adjacent floor slabs. The wall slabs have a tie plate protruding from the top portion thereof and a tie plate embedded in the bottom portion thereof. The protruding tie plate in the common connection scheme includes at least a pair of apertures spaced above one another and arranged substantially normal to the floor slab tie plate aperture. Connection brackets which are L-shaped and have at least an aperture in each surface are arranged with the aperture in one surface in alignment with the aperture in the adjacent floor slab tie plate aperture and the aperture in the other surface in alignment with the lower aperture in the protruding tie plate of the lower wall slab. A similar connection is made for the adjacent floor slab with another L-shaped connection bracket, the lower wall slab protruding tie plate being common to the adjacent floor slabs, with the lower aperture in the protruding tie plate being common to the aperture in the other surface of both connection brackets. Bolting means are connected through these aligned apertures to directly connect the adjacent floor slabs to the connection brackets and to the lower slab protruding tie plate. Similar connection brackets and bolting means are utilized to directly connect the upper slab tie plate, which is embedded in the lower portion, to these connection brackets and to the upper aperture of the lower slab protruding tie plate whereby the adjacent wall and floor slabs are directly connected together.  
  In the instance where there is no adjacent wall to wall interconnection, such as intermediate along the wall or at the roof of the structure, the protruding tie plate of the wall slab has only one level of apertures, the adjacent floor slabs being directly connected thereto via connection brackets and bolting means in the manner discussed above with respect to interconnection of the lower wall slab to the adjacent floor slabs.  
  At the end walls of the structure in this other arrangement, the lower end wall slab top portion has a recess therein in which the adjacent wall slab rests, the lower slab tie plate protruding therefrom and having at least a pair of apertures spaced above one another, one being located in the lower slab recess. The upper end wall slab also has a recess in the lower portion, an L- shaped tie plate means being embedded therein, this tie plate having an aperture in each surface, the aperture in one surface being aligned with the upper aperture in the lower slab protruding tie plate. Thereafter, the direct interconnection of the adjacent end wall slabs and the floor slab is similar to that previously described wherein L-shaped connection brackets and bolting means are utilized to connect both the floor slab and the upper end wall slab to the lower end wall slab protruding tie plate.  
  In constructing such a structural system, the supporting wall slabs are preferably anchored to the wall or foundation below by bolting, the appropriate floor slabs are then placed thereon and aligned and the adjacent side portions thereof directly connected together also by bolting, and, thereafter, the end portions of these wall slabs are directly connected to the supporting wall slabs by bolting to complete the erection of a floor. Thereafter, this procedure is repeated for the next subsequent floor and so on until the building is completed.  
 BRIEF DESCRIPTION OF DRAWINGS FIG. I is a fragmentary typical floor plan of a structure constructed in accordance with our previous invention&#39;,  
  FIG. 2 is a partial perspective view of a typical structure in accordance with our previous embodiment of the invention;  
  FIG. 3 is an exploded perspective view similar to FIG.  
  FIG. 4A is a front elevation of an embodiment of a typical shear wall slab in accordance with the embodiment of FIG. 1;  
  FIG. 4B is a plan view of the shear wall slab shown in FIG. 4A;  
  FIG. 5 is a front elevation of a typical bearing wall slab in accordance with the embodiment of FIG. 2;  
  FIG. 6 is a plan view of a typical floor slab in accordance with the embodiment of FIG. 2;  
  FIG. 7 is a fragmentary cross-sectional view of a typical anchor connection between adjacent bearing wall slabs and floor slabs in accordance with the embodiment of FIG. 2;  
  FIG. 8 is a fragmentary side elevation of the arrangement shown in FIG. 7;  
  FIG. 9 is a fragmentary plan view of the arrangement shown in FIG. 7;  
  FIG. 10 is a fragmentary sectional view similar to FIG. 7 of the interconnection of adjacent floor slabs at a bearing wall slab;  
  FIG. 11 is a fragmentary side elevation of the arrangement shown in FIG. 10;  
  FIG. 12 is a fragmentary plan view of the arrangement shown in FIG. 10;  
  FIG. 13 is a fragmentary cross-sectional view of a typical anchor connection between adjacent end bearing wall slabs and a floor slab;  
  FIG. 14 is a fragmentary cross-sectional view similar to FIG. 13 of a typical connection of an end bearing wall slab to an adjacent floor slab;  
  FIG. 15A is a fragmentary cross-sectional view of a typical connection between adjacent floor slab side portions or a floor slab to shear wall slab interconnection;  
  FIG. 15B is a fragmentary plan view of the arrangement shown in FIG. 15A;  
  FIG. 16 is a fragmentary cross-sectional view of a typical shear wall slab to shear wall slab interconnection in accordance with the embodiment of FIG. 1;  
  FIG. 17 is a fragmentary sectional view similar to FIG. 10 of the preferred interconnection of adjacent floor slabs at a bearing wall slab in the preferred embodiment of the present invention;  
  FIG. 18 is a fragmentary cross-sectional view similar to FIG. 7 of the preferred typical anchor connection between adjacent bearing wall or shear wall slabs and floor slabs in accordance with the preferred embodiment of the present invention;  
  FIG. 19A is a fragmentary cross-sectional view of the preferred typical anchor connection between adjacent end bearing wall slabs and a floor slab in the preferred embodiment of the present invention;  
  FIG. 19B is a fragmentary end view of the arrangement shown in FIG. 19A,  
  FIG. 20 is a fragmentary cross-sectional view of adjacent bearing wall slabs and floor slabs at a typical nonanchor bearing wall joint;  
  FIG. 21A is a fragmentary cross-sectional view similar to FIG. 15A of a typical preferred connection between adjacent floor slab side portions; and  
  FIG. 21B is a fragmentary plan view similar to FIG. 15B of the arrangement shown in FIG. 21A.  
 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An initial unperfected experimental embodiment of the invention was installed by applicants in Jersey City,  
 NJ. in Jan. of 1973. Subsequent experimentation,  
 which was successfully concluded in the summer of I973 and which was based on an evaluation of this experimental installation resulted in the now perfected and preferred embodiment of the structural system and.  
 construction method which are claimed herein. Based on this experimentation the preferred tolerance in the.  
 apertures associated with the various connection brackets, tie plates and connector plates utilized in the.  
 preferred method and structural system of the present invention to accomplish the preferred flor slab-to-floor slab, wall slab-to-wall slab, and floor slab-to-wall slab interconnections, which will be described in greater detail hereinafter, is l&#34;/s inches For purposes of completeness, we shall initially describe our previous construction system, which is the subject of our previously granted U.S. Pat. No. 3,775,928, with reference to FIGS. 1-16 and thereafter we shall describe the presently preferred structural system and method which was the subject of the previously referred to experimentation.  
  Referring now to the figures in detail and especially to FIGS. 1-3 thereof, one typical arrangement of the structural system described in our US. Pat. No.  
 3,775,928 generally referred to by the reference number 20, is shown. Generally describing this structural system 20, a typical structure preferably includes pairs of spaced apart substantially planar upstanding concrete bearing wall slabs, eight such slabs 22, 24, 26, 28, 30, 32, 34 and 36 being illustrated by way of example in FIG. 1, upon which a plurality of preferably flat planar concrete floor slabs are preferably supported and secured thereto. Twenty such typical floor slabs 38 through 76 inclusive are shown illustratively either in whole or in part in FIG. 1 by way of example.  
  As will be described in greater detail hereinafter, such a structure 20 may also include shear wall slabs 78, which are preferably normal to the bearing wall slabs 22 through 36 inclusive and which are preferably located along the longitudinal axis of the building structure 20.  
  Referring now to FIGS. 2 and 3, and to be described in greater detail hereinafter, a typical pair of bearing wall slabs 22 and 24 have floor slabs 46, 48 and 50 and floor slabs 54, 56 and 58 supported thereon with bearing wall slab 24 being a common supporting wall slab for these floor slabs. Each of the floor slabs includes a pair of opposed end portions 80 and 82, a pair of opposed side portions 84 and 86 and a top portion 88 and an opposed bottom portion 90. The same reference numerals will be utilized for each of these respective portions for each of the floor slabs, each particular floor slab respective portions being differentiated by means of subscripts a, b, c, d, e, f, g, h,j, k, m, n, p, q, r, s, t, v, w and x for floor slabs 38 through 76, trespectivcly, with a single respective subscript being associated with only one floor slab.  
  Before describing a typical structure 20 constructed in accordance with one arrangement described in US. Pat. No. 3,775,928, the component shear wall slabs, bearing wall slabs and floor slabs utilized in constructing such a structural arrangement 20 shall be described with reference to FIGS. 4A, 4B, 5 and 6, respectively. The preferred structural arrangement in accordance with the present invention shall be described thereafter with reference to FIGS. 17-21. Referring initially to FIGS. 4A and 48, a typical shear wall slab, such as shear wall slab 78, is shown by way of example. Preferably, such a shear wall slab 78 is formed from concrete and has a plurality tie plates 100, 102, 104, 106, 108 and 110, shown by way of example, embedded therein, preferably during the casting of the concrete shear wall slab 78, such tie plates preferably being composed of rigid structural steel. Preferably, tie plates 100 and 102 are spaced apart on the top portion of the shear wall slab so as to be located respectively adjacent the end portions 112 and 114 of the shear wall slab 78. These tie plates 100 and 102 preferably are upstanding and protrude from the top portion 111 of the shear wall slab 78. Each of the tie plates 100 and 102 preferably has a plurality of apertures therein, five such apertures 116, N8, 120, I22 and 124 for plate 100 and 126,128,130, 132 and 134 for plate 102 being shown by way of example in FIG. 4A. Similarly, plates 108 and 110 have apertures therein, one such aperture 136 for plate 108 and 138 for plate 110 being shown by way of example. Plates 108 and 110 are also preferably spaced apart towards the center of the shear wall 78 and are preferably located in recesses 140 and 142, respectively, formed in the top portion 111 of the shear wall slab 78. The tie plates 104 and 106, which are preferably structurally similar to tie plates and 102 are preferably located in the same relative positions along the slab 78 bottom portion 144 with respect to end portions 112 and 114 as tie plates 100 and 102, respectively, for a purpose to be described in greater detail hereinafter. Thus, tie plate 104 is preferably located at the same distance from end portion 112 as tie plate 100 and is preferably of the same extent and tie plate 106 is located at the same distance from end portion 114 as tie plate 102 and is preferably of the same extent. Furthermore, tie plate 104 preferably has the identical number of apertures, 146, 148, 150, 152 and 154 in the example shown, as tie plate 100, each of these apertures preferably being spaced apart from each other and from end portion 112 as corresponding apertures 116 through 124 of tie plate 100 for a purpose to be described in greater detail hereinafter.  
  Similarly, tie plate 106 preferably includes the identical number of apertures, 156, 158, 160, 162 and 164 in the example shown, as tie plate 102, which apertures are spaced apart from each other and from end portion 114 preferably at the same distances as corresponding apertures 126 through 134 in tie plate 102 for a purpose to be described in greater detail hereinafter.  
  In addition, as will be described in greater detail hereinafter, the location of tie plate 104 on bottom portion 144 with respect to tie plate 100 on top portion 111 is offset from each other (see FIG. 16) as is the respective locations of tie plates 106 and 102. As shown and preferred in FIG. 4A, tie plates 104 and 106 are preferably located in recesses 166 and 168, respectively, formed in the bottom portion 144 of the shear wall slab 78. The interconnection of adjacent shear wall slabs will be described with reference to FIG. 16 in greater detail hereinafter and the interconnection of an adjacent floor slab and shear wall slab will be described in greater detail hereinafter with reference to FIGS. 15A and 15B.  
  Referring now to FIG. 5, a typical preferred bearing wall slab, such as bearing wall slab 24, is shown by way of example in FIG. 5. Preferably, all the bearing wall slabs are of substantially the same configuration and will not be described in greater detail hereinafter. The bearing wall slab 24 has a top portion 170 and opposed bottom portion 172, a pair of opposed end portions 174 and 176 and a pair of opposed side portions 178 and 180. Preferably, a plurality of tie plates, which are preferably composed of rigid structural steel, are embedded in the concrete bearing wall slab 24 during the casting thereof. These tie plates, eight such tie plates 182, 184, 186, 188, 190, 192, 194 and 196 being shown by way of example, preferably protrude from the top portion 170 of the bearing wall slab 24. Each of these tie plates 182 through 196 inclusive preferably has an aperture therein, one such aperture 198 through 212, respectively, being shown by way of example in each of the tie plates 182 through 196 inclusive. Each of the tie plates 182 through 196 inclusive are longitudinally spaced apart along the top portion 170 of the bearing wall slab 24. Preferably, at least two of these tie plates, 186 and 194, have bolting means 214 and 216, respectively, protruding from the top portion thereof for direct interconnection of this bearing wall slab to an overlying bearing wall slab which will be described in greater detail hereinafter with reference to FIGS. 7 through 9. Preferably, these anchor tie plates 186 and 194 are located near the end portions 176 and 174, respectively, of bearing wall slab 24.  
  As shown and preferred in FIG. 5, the bottom portion 172 of bearing wall slab 24 includes a pair of spaced apart recesses 218 and 220 which are preferably located, respectively, at the same longitudinal position from respective end portions 176 and 174 as anchor tie plates 186 and 194, respectively. Each of these recesses 218 and 220 preferably includes a Hat rigid plate 222 and 224, respectively, preferably composed of structural steel, each having a pair of apertures 226 and 228 for plate 222 and 230 and 232 for plate 224 which are preferably located at the same longitudinal position as corresponding bolting means 214 and 216, respectively, for direct interconnection with an underlying bearing wall slab in the manner illustrated in FIGS. 7 through 9.  
  Referring now to FIG. 6, a typical preferred concrete floor slab 58 is shown by way of example, all floor slabs in this structural system preferably being substantially identical in structure. Preferably, each of the end portions 80m and 82m of floor slab 58 each include a pair of spaced apart tie plates 240 and 242 for end portion 80m and 244 and 246 for end portion 82m. As shown in FIGS. 9 and 12 and as will be described in greater detail hereinafter, each of these tie plates 240 through 246 inclusive preferably consists of a tubular piece of structural steel which has been embedded in the concrete floor slab 58 preferably during the casting thereof and which also preferably includes an aperture extending through the outermost portion thereof. The preferred shape of this tubular tie plate 240 to 246 inclusive can be obtained by reference to FIGS. 7, 9, l0, and 12 which will be referred to in the detailed explanation of the direct interconnection of the floor slabs to the bearing wall slabs.  
  As also shown and preferred in FIG. 6, each of the side portions 84m and 86m of the floor slab 58 includes a plurality of recesses therein, 248, 250 and 252 for side portion 84m and 254, 256 and 258 for side portion 86m. As can be seen by reference to FIGS. 15A and 158, each of these recesses 248 through 258 inclusive preferably includes a structural steel plate, such as one formed of angle iron structural steel embedded in the concrete during the casting of the floor slab. As can be seen with reference to FIG. 15A, the recesses 248 through 258 are preferably notches in the side portions 84m and 86m and donot extend completely between the top portion 88m and the bottom portion 90m of the floor slab 58. Each of the plates 260 through 270 inclusive located in the recesses 248 through 258 inclusive preferably include a pair of spaced apart apertures therein as illustrated trated in FIG. 158 for enabling direct interconnection of adjacent side portions of adjacent floor slabs in a manner to be described in greater detail hereinafter.  
  Now that the typical shear wall slab 78, bearing wall slab 24 and floor slab 58 have been described in greater detail above, the various interconnections of these components in the structural system of the present invention shall be described in greater detail hereinafter with reference to FIGS. 7 through 16.  
 Anchor connection between bearing wall slabs and floor slabs Referring now to FIGS. 7 through 9, a typical preferred anchor connection between adjacent bearing wall slabs and floor slabs is shown. By the use of the term anchor connection it is meant that the upper bearing wall slab 272 is physically secured to the lower bearing wall slab 22 and is, therefore, anchored thereto. The upper bearing wall slab 272 shown by way of example in FIG. 7 is omitted from FIGS. 2 and 3 for clarity and is mounted in the structure 20 illustrated in FIG. 2 preferably spaced apart from bearing wall slab 274 illustrated therein and is anchored to lower bearing wall slab 24 in the manner illustrated in FIGS. 7 through 9. In securing the upper bearing wall slab 272 directly to the lower bearing wall slab 24 and the adjacent end portions 82g and m of floor slabs 50 and 58, respectively, together, the floor slabs 58 and 50 are preferably placed on the lower supporting bearing wall slab 24. As shown and preferred in FIG. 7, anchor plate 186 protruding from the top portion of bearing wall slab 24 is preferably located in the center of the top portion along the longitudinal axis of the top portion of bearing wall slab 24 so as to provide an equal supporting surface for the adjacent end parts of floor slabs 50 and 58, respectively.  
  The tie plates 246 and 244 for end portion 82g of floor slab 50 are placed on top of bearing wall slab 24 with the aperture in one of these tie plates aligned with the aperture 202 in anchor plate 186, and the other tie plate aperture aligned with the aperture in another bearing wall slab 24 tie plate, such as plate 188 whose interconnection will be described in greater detail hereinafter with reference to FIG. 10. The upper bearing wall 272 is preferably placed on top of lower bearing wall 24 by aligning the apertures 226 and 228 in plate 222 at the bottom portion of bearing wall 272 with the bolts 214 protruding from anchor plate 186. As shown. and preferred, preferably a cement asbestos shim 276 is initially placed on the floor slabs 50 and 58 over the bolts 214 prior to the placement of the plate 222 thereover to provide additional support during erection. The upper bearing wall 272 is then secured to the lower bearing wall 24 by means of tightening a nut 278 on each of the bolts or studs 214, which are preferably threaded, until the desired proof of load is obtained and a desired relative position between the bearing wall slabs 272 and 24 and the floor slabs 50 and 58 is achieved. The adjacent floor slabs 50 and 58 are directly secured to each other and to the supporting bearing wall slab 24 by means of threading a bolt 280 through the aligned apertures in the tie plates 246 and. 242 and anchor plate 186, which apertures form a through hole, the bolt 280 having a head 284 prefera-. bly being threaded, and thereafter tightening nut 282 on bolt 280 until the desired proof of load is obtained and the slabs are directly secured together in a desired. predetermined position relative to each other.  
  This connection is likewise repeated for the opposite end portions of floor slabs .50 and 58, respectively. Thus, this anchor connection is resistant to the collapse of either floor slab 50 or 58, such as due to local explosion and in the event of such collapse the remaining floor slab and bearing wall slabs will still be fixedly secured together in position by the bolting arrangements previously described. These bolting arrangements provide a direct interconnection between the upper and lower bearing wall slabs and the adjacent floor slab end portions.  
  As shown and preferred in FIG. 7, in order to tighten the interconnection between the adjacent end portion of the floor slabs 50 and 58, conventional steel shims 286 and 286&#39;, respectively, may be driven in conventional fashion between the end portion 82g and anchor tie plate 186, and between the end portion 80m and anchor tie plate 186, respectively, in order to fill any gap existing therebetween. Furthermore, as shown and preferred, if desired, cement asbestos cloth bearing pads 288 and 290 may be placed on top of the lower supporting bearing wall slab 24 between the top surface thereof and the bottom surface of the end parts of the floor slabs 50 and 58 resting thereon in order to compensate for any irregularities in these surfaces. Preferably, all anchor connections between bearing wall slabs and floor slabs, other than end bearing wall anchor connections, are accomplished in this manner in the structural system 20.  
 Floor slab to floor slab connection on unanchored bearing wall portion Referring now to FIGS. 10 through 12, a typical preferred direct interconnection between adjacent floor slab end portions supported on the bearing wall slab at a point along the bearing wall slab other than where the lower bearing wall slab 24 is anchored to the upper bearing wall slab 272 at anchor tie plates 186 and 194 is shown, such as at tie plate 188 on bearing wall slab 24. As was previously mentioned, the upper bearing wall slab 272 is preferably only anchored to lower bearing wall slab 24 at two points adjacent the ends of the lower bearing wall slab 24, these points being at anchor tie plates 186 and 194, respectively, via associated plates 222 and 224, respectively, of upper bearing wall slab 272. The direct interconnection of the adjacent end portions 82g of floor slab S and 80m of floor slab 58 are preferably interconnected in the same manner as previously described with reference to FIG. 7 with the exception that tie plate 188 is the plate to which the end portions are fastened rather than anchor tie plate 186. Once again, tie plates 240 and 244 associated with the end portions 80m and 82g of floor slabs 58 and 50, respectively, are preferably tubular structural steel. The end parts of the floor slabs 50 and 58 are placed on the top surface portion of lower supporting bearing wall slab 24 and the apertures in tie plates 240 and 244, respectively, are aligned with the aperture 204 in tie plate 188, as previously mentioned. Thereafter, a bolt 292 having a head 294 is threaded through the through hole formed by these apertures and a nut 296 is threaded thereon and tightened to proof the load until the desired predetermined relationship between the adjacent floor slab end portions is obtained.  
  As shown and preferred (see FIG. 10), the tie plate 188 is also preferably located in the center of the top surface of supporting bearing wall slab 24 along the longitudinal axis thereof as are all of the tie plates 182 through 196 inclusive. In addition, as was previously mentioned with respect to the anchor interconnection of the bearing wall slabs, conventional steel shims 298 and 300, respectively, may be conventionally driven between end portion 82g of floor slab 50 and tie plate 188 and end portion 80m of floor slab 58 and tie plate 188, respectively, to further tighten the connection and fill any gap formed therebetween. Thus, in the example previously described, floor slab 58 has its end portion 80m directly secured to the supporting bearing wall slab 24 at tie plates 186 and 188, respectively, by means of bolts 280 and 292, respectively. Furthermore,  
 upper bearing wall slab 272 is anchored to lower bearing wall slab 24 at anchor tie plates 186 and 194 by means of bolts 214 and 216 and associated nuts 278 in the manner previously described above.  
  Preferably, the direct interconnection of floor slabs at the bearing wall slabs throughout the structural system 20 is preferably as shown and described with reference to FIGS. 10 through 12 except at the anchor connections between an upper bearing wall slab and a lower bearing wall slab or the foundation of the structure where the interconnection is preferably as shown and described previously with reference to FIGS. 7 through 9.  
 Anchor connection between end bearing wall and floor slab Referring now to FIG. 13, a typical preferred anchor connection between an end bearing wall slab, that is a bearing wall slab at the extremities of the structure 20, and an adjacent floor slab is shown. Preferably, the direct interconnection of the upper bearing wall slab 310 to the lower supporting bearing wall slab 312 is similar to that previously described with reference to FIGS. 7 through 9 wherein the direct interconnection of bearing wall slabs other than end bearing wall slabs is described. The primary difference between the lower supporting end bearing wall slab 312 and a typical supporting bearing wall slab 24 is in the configuration of the upper portion thereof. As shown and preferred in FIG. 13, rather than being symmetrical about the tie plate 314 which protrudes from the upper surface of bearing wall slab 312, the bearing wall slab 312 upper portion is formed with a notch-like arrangement for receiving a floor slab on the innermost side of the tie plate 314 and provides a flush concrete surface 316 on the opposite side so as to provide an outer wall for the structure. This portion is formed with a recess 318 adjacent the tie plate 314 which closes this recess, except for an aperture 320 in tie plate 314. A bolt 322 having a head 324 is threaded through this aperture 320, apertures 320 being aligned with an aperture in tie plate 242 embedded in floor slab 330 to form a through hole therebetween, and is fastened in position by means of tightening a nut 332 to proof the load until the floor slab 330 is in a desired predetermined position with respect to supporting bearing wall slab 312.  
  As was previously mentioned, a conventional steel shim 334 may be driven in conventional fashion between tie plate 242, which is preferably a tubular structural steel tie plate located at the end portion of floor slab 330, and the tie plate 314 to tighten the interconnection and fill any gap therebetween. Tie plate 314 is preferably an anchor tie plate identical with either anchor plate 186 or 194 and has a bolt assembly 340 protruding therefrom. The upper bearing wall slab 310 is mounted on the lower bearing wall slab 312 by aligning the apertures in the associated plates 222 or 224 with the respective bolt assembly 340. After the bolt assembly 340 is passed through the respective apertures, nuts 342 are tightened to proof the load to the desired amount until the bearing wall slabs 310 and 312 and the floor slab 330 are in the preferred predetermined position relative to each other. As was previously mentioned, if desired a cement asbestos shim 344 may be placed over the bolt assembly 340 between the plate 222 and the upper surface of floor slab 330 and supporting bearing wall slab 312 to provide temporary support during erection although remaining in position in the structure thereafter. Preferably, all end bearing wall anchor connections with floor slabs are accomplished in this manner in the structural system 20.  
 Floor slab to end bearing wall interconnection Referring now to FIG. 14, a typical preferred direct interconnection between and end bearing wall slab and a floor slab along the supporting bearing wall slab top surface at a point other than where the anchor connections of the upper and lower bearing wall slabs occur is shown. The direct interconnection of the floor slab 330 to the lower supporting bearing wall slab 312 is preferably identical to that previously described above with reference to FIG. 13 with the exception that the tie plate 350 does not have a bolt assembly protruding therefrom so that there is no such means for interconnecting the upper bearing wall slab 310 to the lower supporting bearing wall slab 312 at this point. Other than that the direct interconnection of the floor slab 330 to the bearing wall slab 312 is accomplished in the manner previously described with reference to FIG. 13 and will not be described in greater detail hereinafter. Suffice it to say that the tubular structural steel tie plate 240 located at one end 80 of the floor slab 330 is aligned with the aperture 352 in tie plate 350, the configuration of the end bearing wall slab 312 at this point preferably being identical with that previously described with reference to FIG. 13 at the point of anchor connection between the upper and lower bearing wall slabs 310 and 312. A bolt 354 having a head 356 is threaded through the through hole formed by the aperture in tie plate 240 aligned with the aperture 352 in tie plate 350 and a nut 358 is tightened to proof the load to the desired value and secure the floor slab 330 end portion at this point in the preferred relative position with respect to supporting wall slab 312. As was also previously mentioned, if desired, a conventional steel shim 360 may be conventionally driven between end portion 80 and tie plate 350 to further tighten the interconnection between the floor slab 330 and the bearing wall slab 312 and to fill any gap therebetween.  
  As was also previously mentioned, an asbestos cloth 362 may be placed on the top surface of the supporting bearing wall slab 312 between this surface and the abutting bottom surface of floor slab 330 to compensate for any irregularities in the concrete as was also true with respect to bearing pads 302 and 304 referred to with reference to FIG. and bearing pads 288 and 290 referred to with reference to FIG. 7 and bearing pad 346 referred to with reference to FIG. 13. Preferably, the direct interconnection of floor slab to end bearing wall slab throughout the structural system 20 of the present invention is preferably as shown and described with reference to FIG. 14 except at the anchor connections between an upper end bearing wall slab and a lower end bearing wall slab or the foundation of the structure where the interconnection is preferably as shown and described previously with reference to FIG. 13.  
 Slab to slab side connection Referring now to FIGS. 15A and 15B a typical preferred interconnection between adjacent side portions of adjacent floor slabs or an adjacent side portion of a floor slab and an adjacent shear wall slab is shown. By way of example, a typical interconnection between the side portions of adjacent floor slabs 48 and 46 is shown. The adjacent floor slabs 48 and 46 have their side portions 86f and 84e, respectively, adjacent each other and preferably slightly spaced apart from one another. A connector plate 370, preferably formed of a rigid structural steel having apertures 372 through 378 inclusive therein is preferably placed in the communicating recesses 254 and 248 of floor slabs 48 and 46 with the apertures therein aligned with the apertures in the plates 266 and 260, respectively. Bolts 380 and 382 having heads 381 and 383, respectively, are preferably threaded through the through holes formed by the aligned apertures in connector plate 370 and plate 266, and bolts 384 and 386 having heads 385 and 387, respectively, are threaded through the through holes formed by the aligned apertures in connector plate 370 and plate 260. Thereafter, nuts 388, 390, 392 and 394 are tightened on bolts 380, 382, 384, and 386, respectively, to proof the load to the desired value until the adjacent floor slab side portions 86f and 84e are in the preferred predetermined relationship to each other. In this manner, connector plate 370 also acts to level the adjacent floor slabs with respect to each other as well as to interconnect the adjacent slab side portions.  
  Preferably, if desired, at some time subsequent to the interconnection of the floor slabs, the gaps existing therebetween may be filled with conventional grouting although such grouting is not necessary for structural support. As was previously mentioned, a floor slab may be connected to a shear wall slab, such as shear wall slab 78, in this manner with a connector plate 370 connecting the floor slab to a plate in a recess at the top of the adjacent shear wall slab, such as plate 136 in re cess 108 or plate 138 in recess 110, so as to transfer any loads laterally transferred across the floor slab to the shear wall slab where, thereafter, these loads may be vertically transferred downwardly through the structure. Furthermore, the interconnection of adjacent floor slabs in the manner previously described above serves to laterally transfer and distribute loads throughout the structure. Preferably, all side connections between adjacent floor slabs and all side connections between adjacent floor slabs and shear wall slabs are accomplished in this manner in the structural system 20.  
 Shear wall to shear wall interconnection Referring now to FIG. 16 a typical preferred arrangement for interconnecting an upper shear wall slab 400 to a lower shear wall slab 78 is shown. As was previously mentioned with reference to FIGS. 4A and 4B,.  
 the upper tie plates and 102 of a typical shear wall slab 78 are offset from the lower tie plates 104 and 106 of the typical shear wall slab. Consequently, when these shear wall slabs are preferably placed one on top of the other, the adjacent tie plates, such as 100 and 104, are aligned next to each other to form corresponding through hole pairs of apertures 116-146, 118-148, l20-150, 122-152, and 124-154. This arrangement likewise holds for adjacent tie plates 102 and 164 forming through hole pairs of apertures 126-156, 128-158, 130-160, 132-162, and 134-164. Bolts such as typical bolt 402 having a head 404 thereon are preferably threaded through the respective aperture pairs and associated nuts 406 are tightened thereon to proof the load to a desired value so as to directly connect the upper and lower shear wall slabs 400 and 78 together in a predetermined position relative to each other. In  
 this manner applied loads which are transferred to an upper shear wall slab connected to an adjacent floor slab at the side portion thereof, such as in the manner previously described with reference to FIGS. A and 15B, are then vertically transferred from the upper shear wall slab to the lower shear wall slab and so forth downwardly throughout the structure to the foundation. Thus, laterally applied loads across the floor slabs are vertically transferred through the structure by means of the shear wall slabs.  
  Now generally describing the manner of constructing a building structure 20 in accordance with the invention described in U.S. Pat. No. 3,775,928. The foundation for the building comprises a plurality of slabs each having upstanding anchor tie plates similar to anchor plates 186 and 194. If desired, wall supporting shim pads similar to shim pad 276 may be placed over the bolt assembly associated with these anchor plates so as to provide a true level base for the next lift of wall slabs. A bearing wall slab is then lifted into position using the projecting bolt assembly, such as bolt assembly 214, from the lower wall slab or foundation slab anchor plate as a guide, the associated plates 222 and 224 being aligned with these bolt assemblies so as to have the bolt assemblies pass through the apertures therein. The bearing wall slab is installed to line and braced to plumb. The anchor connection of this bearing wall slab to the underlying foundation slab or lower supporting bearing wall slab is then made by tightening the appropriate nuts, such as nut 278, such as by a conventional torque wrench. In this manner the upper bearing wall slab is anchored to the foundation or to the bearing wall slab below if a floor above the foundation is being constructed.  
  The floor slabs are then lifted into position on appropriate spaced apart pairs of bearing wall slabs and their respective end portion tie plates are aligned with those of the supporting bearing wall slabs upon which the floor slab rests so as to align the apertures therein with the apertures in the tie plates protruding from the supporting bearing wall slab so as to form through holes. This is repeated for all of the floor slabs to be supported between the bearing wall slabs, the floor slabs being serially arranged side to side along the length of the bearing wall slabs. Thereafter, the adjacent side portions of the floor slabs are interconnected in the manner illustrated in FIGS. 15A and 15B by the insertion of appropriate connector plates 370 and the tightening of nuts 388 through 394 associated with the plates 260 through 270 inclusive. After the adjacent side portions of the adjacent floor slabs are directly connected together by these bolt connections, the end portions of the floor slabs are connected to the associated tie plates of the lower supporting bearing wall slab, such as slab 24, in  
  the manner previously described with reference to FIGS. 7 through 9 if the associated tie plate is an anchor tie plate, and in the manner previously described with reference to FIGS. 10 through 12 if the associated bearing wall slab tie plate is not an anchor plate.  
 Preferably, when a complete bay of floor slabs is installed, a bay being defined as a pair of bearing wall slabs and the required plurality of floor slabs necessary to cover the length of the bearing wall slabs, the steel shims, if desired, are driven. This is preferably done prior to the bolting of the end portions of the floor slabs to the lower supporting bearing wall slab. This completes the erection cycle for a given bay and erection can then proceed to the next bay or floor, although it should be noted that adjacent bays share a common wall slab therebetween and the adjacent end portions of the floor slabs are interconnected to the common tie plates on the common bearing wall slab in the manner previously described with reference to FIGS. 7 and 10. Similarly, if the structure contains shear wall slabs then the tie portions of the floor slabs adjacent thereto are interconnected thereto in the manner previously described with reference to FIGS. 15A and 15B. Such a typical shear wall slab 78 is shown in the fragmentary floor plan view of FIG. 1. It should be noted that preferably the shear wall slabs are located along the longitudinal axis of the structure and do not extend the entire width of the structure but rather only a portion thereof although preferably vertically extending substantially the entire height of the structure.  
 PREFERRED EMBODIMENT Referring now to FIGS. 17 through 21, the presently preferred arrangement for the structural system of the present invention (hereinafter referred to as the more preferred arrangement as compared with our U.S. Pat. No. 3,775,928) is shown and shall be described in greater detail hereinafter. As illustrated in these figures, all floor slabs in the more preferred arrangement of the structural system of the present invention are substantially identical in structure. Furthermore, as opposed to the floor slab in the arrangement shown in FIG. 6, the more preferred typical concrete floor slab 58A preferably includes identical connection means about the periphery of the floor slab 58A; that is, with respect to both the side portions and the end portions of the typical floor slab 58A. Preferably, each of the end portions and side portions of the typical floor slab 58A comprise a plurality of recesses 600, 602, 604, 606, four such recesses being shown in section by way of example, the recesses being similarly located with the recesses illustrated in FIG. 6, a tie plate being embedded in the concrete floor slab 58A preferably during the casting thereof. Each of these tie plates 608, 610, 612, 614, by way of example, are preferably identical in structure and preferably comprise an L-shaped structural steel angle having an aperture extending therethrough in the surface thereof which is substantially parallel to the top surface of the floor slab 58A. As was previously mentioned, these tie plates 608, 610, 612 and 614 are preferably identical whether located in a recess in the end portion of the floor slab 58A, as illustrated in FIGS. l7, l8 and 19A, or in a recess in the side portion of the floor slab 58A, as illustrated in FIG. 21A.  
  Now referring to FIGS. 17, 18 and 20, a typical preferred wall slab 24A, which may be utilized either as a bearing wall slab or a shear wall slab in the more preferred typical arrangement of the present invention illustrated in FIGS. 17 through 21, is shown. Preferably, except for the end wall slabs 620 and 622, to be described in greater detail hereinafter with reference to FIGS. 19A and 19B, are the bearing wall slabs and shear wall slabs in the more preferred structural arrangement of the present invention are of substantially the same configuration having a top portion, an opposed bottom portion and a pair of opposed end portions and a pair of opposed side portions. Preferably, a plurality of tie plates, which are preferably composed of rigid structural steel, are embedded in the concrete wall slab 24A during the casting thereof. These tie plates preferably protrude from the top portion 624 of the wall slab 24A at preselected positions therealong. These protruding tie plates are preferably of two types 626 and 628 depending on whether the interconnection to be made includes a direct connection to an adjacent wall slab situated directly above. Such an arrangement is illustrated in FIG. 18 which shows a typical anchor connection between adjacent floor slabs 58A and adjacent wall slabs 24A. In such an instance, the protruding tie plate 626 includes a plurality of apertures therein which are spaced apart from each other and above each other, two such apertures 630 and 632 being shown in section by way of example in FIG. 18. With respect to the instance where the wall slab 24A is not directly connected to an adjacent wall slab located above, such as at a roof connection for the structure or an intermediate connection other than an anchor connection along the wall wherein the wall slab is directly connected to adjacent floor slabs supported thereon, the tie plate 628, as illustrated in FIG. 17, preferably only has one level of apertures, one such aperture 634 being shown in section by way of example in FIG. 17.  
  With respect to the bottom portion of the typical wall slab 24A, other than an end wall slab 622, a flat tie plate 640 of structural steel is preferably embedded in the bottom portion 642 of the wall slab 24A which is a concrete slab, preferably during the casting thereof. A plurality of these tie plates 640 are preferably located along the bottom portion 642 of the wall slab 24A at preselected positions. As shown in FIG. 18, this bottom tie plate 640 is utilized solely in the interconnection of adjacent wall slabs 24A to the wall slab below. This tie plate 640 preferably has a plurality of apertures the rein for this purpose, two such apertures 644 and 646 being shown in section by way of example in FIG. 18. As also shown in FIG. 18, these tie plates 640 are preferably located in recesses in the bottom portion 642 of the wall slab 24A.  
  Referring now to FIG. 19A, a pair of typical end walls 620 and 622 in the more preferred structural arrangement of the present invention are shown. The top portion 650 of the end wall 620 preferably includes a recess 652 therein and a structural steel tie plate 654 which is preferably angle iron structural steel is preferably embedded in the recess 652 of the concrete end wall slab 620 and protrudes therefrom. This protruding tie plate 654 preferably includes a plurality of apertures which are spaced apart and above each other as shown in FIG. 19A, two such apertures 656 and 658 being shown in section byway of example in FIG. 19A. Preferably. aperture 656 is located along tie plate 654 in the recess 652. As also illustrated in FIG. 19A, the bottom portion 660 of the more preferred end wall slab 622 also preferably includes a recess 662 in which a structural steel angle iron tie plate 664 is embedded such as by being embedded in the concrete end wall slab 622 during the casting thereof. This bottom tie plate 664 preferably does not protrude from the bottom portion 660 and includes an aperture in each of the substantially normal surfaces thereof, one such aperture 666 and 668 being shown in section by way of example in each of the surfaces in FIG. 19A. Now that the structural arrangement of the more preferred typical floor slabs 58A, wall slabs 24A and end wall slabs 620 and 622 have been described in greater detail, typical direct connections between adjacent floor slabs and a supporting wall slab, adjacent floor slabs and adjacent wall slabs, adjacent end wall slabs and an adjacent floor slab, and adjacent floor slabs shall be described by way of example, for the more preferred structural arrangement of the present invention, with reference to FIGS. 17 through 21.  
 FLOOR TO WALL TO FLOOR CONNECTION Referring now to FIG. 17, a typical wall to floor connection in the more preferred structural arrangement of the present invention is shown, such an arrangement capable of being utilized for interconnecting a shear wall to the adjacent floor slabs or a supporting bearing wall to the adjacent floor slabs. As shown and preferred in FIG. 17, structural steel angle iron connection brackets 680and 682 are utilized for directly connecting the adjacent floor slabs 58A to the wall slab 24A via protruding tie plate 628. Each of the L-shaped connection brackets 680 and 682 preferably include an aperture, one being shown by way of example, 684, 686 for bracket 680 and 688 and 700 for bracket 682, in each of the surfaces of the respective connection brackets 680 and 682. The surface of the connection bracket 680 and 682 containing apertures 686 and 700, respectively, preferably substantially parallel to tie plate 628 and the surface of the bracket 680 and 682 containing apertures 684 and 688, respectively, is preferably substantially parallel to the surface of the tie plate 608 and 610 which are parallel to the top portion of the floor slabs 58A. The connection brackets 680 and 682 are placed in the recesses 600 and 602 as illustrated in FIG. 17 with the apertures 686 and 700 in bracket 680 and 682 aligned with aperture 634 and tie plate 628 so as to form a single through hole and the aperture 684 in bracket 680 and 688 in bracket 682 aligned, respectively, with the apertures 609 and 611 in tie plates 608 and 610, respectively. Conventional bolting means, such as a conventional nut and bolt arrangement 702, 704 and 706 are, respectively, placed in the aligned apertures 686-634-700, 684-609, and 688-611, respectively, and tightened so as to secure the floor slabs to the respective connection brackets and the connection brackets to the protruding tie plate 628 of the wall slab 24A. These bolting arrangements provide a direct interconnection between the adjacent floor slabs and the wall slab 24A. As was previously mentioned, since the end portions and side portions of the floor slabs utilize. the same connections, the slab 24A is a shear wall slab then the interconnection illustrated in FIG. 17 is to the. side portions of the floors 58A; however, if the wall slab 24A is a bearing wall or supporting wall slab then the interconnections illustrated in FIG. 17 are to the end portions of the floor slab 58A. As also illustrated in FIG. 17, if desired, in order to tighten the interconnection between the adjacent floor slabs 58A, conventional steel shims 286 and 286&#39;, respectively, may be driven in conventional fashion between the downwardly extending surfaces of the tie plates 608 and 610, respectively, and the protruding tie plate 628 in order to fill any gap existing therebetween.  
 WALL TO FLOOR TO WALL CONNECTION Referring now to FIG. 18, a typical interconnection between adjacent floor slabs and adjacent wall slabs in accordance with the more preferred structural arrangement of the present invention is shown. As was previously mentioned, the interconnection between the adjacent wall slabs 24A illustrated in FIG. 18 is equally applicable to both bearing wall or supporting wall slabs and shear wall slabs in accordance with the more preferred structural arrangement of the present invention. With respect to the interconnection of the adjacent floor slabs 58A to the protruding tie plate 626 of the lower wall slab 24A, this direct connection is preferably identical with that previously described with reference to FIG. 17 with the exception that the adjacent floor slabs 58A via connection bracket 680 and 682 are directly connected to tie plate 626 through the lower aperture 630 of the protruding tie plate 626 via bolting means 702, bolting means 704 and 706 directly connecting the floor slabs 58A to connection brackets 680 and 682 via tie plates 608 and 610, respectively. Accordingly, this portion of the direct interconnection between the floor slabs 58A and the lower wall slab 24A shall not be described in any greater detail, the same reference numerals being utilized for substantially identical functional elements.  
  Now describing the direct interconnection of the upper wall slab 24A to the lower wall slab via protruding tie plate 626 of the lower wall slab. This interconnection is accomplished through upper aperture 632 in tie plate 626 in a fashion similar to that previously described with reference to the interconnection of the floor slabs 58A to the lower wall slab 24A. In order to accomplish this direct interconnection, structural steel angle iron connection brackets 710 and 712, which are preferably identical with connection brackets 680 and 682 are utilized. These connection brackets 710 and 712 each include an aperture, one being shown by way of example in each of the surfaces of the respective connection brackets 710 and 712, the apertures being designated 714 and 716 for bracket 710 and 718 and 720 for bracket 712. The surfaces of connection brackets 710 and 712 preferably comprise one surface which is parallel to tie plate 640, this surface containing apertures 716 and 720, respectively, and one surface which is substantially parallel to the protruding portion of tie plate 626, these surfaces containing apertures 714 and 718, respectively. The connection brackets 710 and 712 are preferably aligned as illustrated in FIG. 18 with aperture 716 and aligned with aperture 644 and tie plate 640 at aperture 720 aligned with aperture 646 in tie plate 640 and with apertures 714 and 718 aligned with aperture 632 in tie plate 626 perform a through hole. Conventional bolting means 730, 732 and 734, respectively, extend through aligned apertures 714-63- 2-718, 716-644, and 720-646 and are tightened in position to fixedly secure the connection brackets 710 and 712 to the protruding tie plate 626 and to the tie plate 640 of upper slab 24A. These bolting arrangements are similar to that previously described with reference to 702, 704 and 706. These bolting arrange ments together with the bolting arrangements 702, 704 and 706 provide a direct interconnection between the upper and lower wall slabs and the adjacent floor slabs. As was previously mentioned, when the upper and lower slabs are bearing wall slabs, this interconnection is to the adjacent floor slab end portion and when these slabs are shear wall slabs then these interconnections are to the adjacent floor slab side portions, the manner of interconnection being preferably identical. Furthermore, if the manner of interconnection of the upper wall to the lower wall slab is equally applicable to the more preferred structural arrangement of the present invention when no interconnection is provided to adjacent floor slabs, connection bracket 680 and 682 not being required in this instance.  
 FLOOR TO END WALL CONNECTION Referring now to FIG. 19A, a typical preferred floor to end wall connection for the more preferred structural arrangement of the present invention is shown. As shown and preferred in FIG. 19A, connection brackets 800 and 802, which are preferably structurally identical with connection brackets 680 and 682 are utilized for directly connecting the wall slab 58A to the end wall slab 620 and the end wall slab 620 to the upper end wall slab 622, the manner of interconnection preferably being similar to that previously described with reference to FIG. 18 with the exceptions enumerated hereinafter. Connection brackets 800 and 802 are preferably structural steel angle iron brackets having an aperture, one being shown by way of example, in each of the surfaces thereof, apertures 804 and 806 being provided in bracket 800 and apertures 808 and 810 being provided in bracket 802. Connection brackets 800 and 802 are preferably aligned as illustrated in FIG. 19A with aperture 804 and bracket 800 being aligned with aperture 611 in tie plate 610 of the floor slab 58A and aperture 806 of bracket 800 being aligned with aperture 656 which is the lower aperture in tie plate 654 of end wall slab 620, and aperture 808 of bracket 802 being aligned with aperture 668 of tie plate 664 of end wall slab 622 and aperture 810 of bracket 802 being aligned with upper aperture 658 of tie plate 654 of the lower end wall slab 620 and aperture 666 of the tie plate 664 of upper end wall slab 622. Conventional bolting means, preferably identical with that previously described with reference to FIG. 18, such as bolting means 702, 704 or 706, extend through the aligned apertures, bolting means 812 extending through apertures 804-611, bolting means 814 extending through apertures 806-656, bolting means 816 extending through apertures 810658-666 and bolting means 818 extending through apertures 808-668. These bolting arrangements fixedly secure the connection bracket 800 to the floor slab 58A and to the tie plate 654 of the lower end wall slab 620, and the connection bracket 802 to the upper end wall slab 622 and to the tie plate 654 of the lower end wall slab 620, and the connection bracket 802 to the upper end wall slab 622 and to the tie plate 654 of the lower end wall slab 620. These bolting arrangements provide a direct interconnection between the upper and lower end wall slabs and the adjacent floor slab.  
  Referring now to FIG. 21A, a typical preferred interconnection between adjacent tie portions of adjacent floor slabs 58A is shown. This interconnection is preferably identical with that previously described with reference to FIGS. 15A and 15B and will not be described in greater detail hereinafter, the same reference numerals being utilized for the connector plate 370 preferably formed of a rigid structural steel having apertures 372 and 378 shown in section in FIG. 21A, which is preferably identical with FIG. 15A. This connector plate 370 is preferably placed in the communicating recesses 604 and 608, in this example, of floor slabs 58A with the apertures therein aligned with the apertures in the tie plates 612 and 614, respectively. Conventional bolting means 380 and 382, previously described with reference to FIGS. A and 15B and which are preferably identical with the other bolting means described above, such as bolting means 702, 704 and 706, are preferably threaded through the through holes formed by the aligned apertures in the connector plate 370 and the tie plates 612 and 614, and the nuts thereafter are tightened on the bolts to proof the load to the desired value to the adjacent floor slab side portions or any preferred predetermined relationship to each other. In this manner, connector plate 370 also acts to level the adjacent floor slabs with respect to each other as well as to interconnect the adjacent slab side portions. The balance of the construction procedure with respect to subsequent grouting if desired, as was previously described with reference to the arrangement illustrated in FIGS. 1 through 16, may be utilized in accordance with the more preferred structural arrangement of the present invention and will not be described in greater detail hereinafter.  
  With respect to FIG. 20, the typical bearing wall joins a point at which no mechanical interconnection between either adjacent floor slabs or adjacent wall slabs is required is shown, a grouting compound 900 being illustrated and placed between the adjacent wall slabs and floor slabs.  
  In a structure 20 constructed in accordance with the arrangement of the present invention wherein the various slabs are directly interconnected by mechanical means such as the preferred bolt assemblies, and wherein the slabs are all preferably precast concrete slabs tied together by dry mechanical joints comprising the bolt assemblies, lateral loads are transferred across the floor slabs onto the bearing wall slabs or shear wall slabs which, in turn, resist the cumulative shear and overturning moments applied to the structure. For example, the horizontal lateral loads are transferred across the floor slabs and subsequently onto the shear wall slabs by dry mechanical joints which create a friction connection therebetween capable of transferring lateral shear between the connected elements such as floor slab to floor slab or floor slab to shear wall slab. Once the lateral loads are transferred onto the shear wall slab, the shear wall slab itself transfers the cumulative loads vertically down onto the next similar slab and subsequently into the foundations of the structure. Once again, the vertical transfer of shear and tension/- compression forces, produced by the overturning moments, is preferably achieved by dry mechanical joints. The shear wall slabs are interconnected by the dry mechanical joints which create a friction connection capable of transferring the combined tension/compression shear loads downwards. The bearing wall slabs transfer shear by friction along their bearing surfaces and resist tension forces due to overturning moments preferably also by dry mechanical joints. Such a system has high resistance to wind and earthquake loads. In addition, the system is preferably ductile by preferably oversizin g all bolt holes so that the system can move under catastrophic loading with considerable energy absorption before the building structure reaches its ultimate capacity. For example, the oversizing of the bolt holes may be thirty to 100 percent of the bolt diameter. Furthermore, in the preferred structural system of the present invention progressive collapse is prevented due to the interconnection of the floor slabs to the bearing wall slab so that when a floor slab collapses on one side of the bearing wall slab, the wall slab is held by the floor slab and its connections on the opposite side. In addition, this system enables automatic leveling of adjacent floor slabs by means of the connector plates previously described in the discussion relating to the side to side floor slab interconnection. Due to the rigidity of this connector plate, adjacent floor slabs may be brought level without recourse to shoring or loading of the slabs. Furthermore, the floor slabs and interconnected bearing wall slabs form self-supporting structural building units capable of transferring lateral and vertical loads during erection so that after the interconnection of the various bolt assemblies to the associated tie plates and connector plates, the relevant floor in the structure has the essential rigidity to be self-supporting vertically and laterally so that the bracing below the floors can immediately be removed as soon as the floor slabs are installed and the connections are bolted.  
  Another advantage of the present invention is that by utilizing dry mechanical joints during the erection process the erection process may be an all-weather erection process since any grouting or welding which may be required is a nonessential part of the erection process and can be done any time afterwards. For exam ple, several floors can be erected in such a structure before any dry packing under the walls or grouting is utilized. Furthermore, preferably, the different types of slabs utilized in the preferred structural system of the present invention are kept to a minimum so that the manufacturing process thereof can be largely repetitive. Thus, in accordance with the present invention, a simplified and rapid erection process requiring a minimum of on site work and skilled site labor and a minimum of post-erection completion work may be accomplished with the resultant structure highly resistant to wind and earthquake loads, the resultant structure acting as a membrane connected to the shear and bearing walls to establish permanent structural stability during construction after the completion of each floor slab. Furthermore, the structural system of the present invention enables the construction of a building structure by the direct interconnection of concrete slabs without the requirement of a structural steel framework for the structure.  
  It should be understood that as used throughout the specification and claims the term direct connection&#34; is meant to define a connection wherein the connected members are in mutually supporting relationship and do not rely for support on an intervening frame. Thus, direct connection includes connection through an interposed member as in FIGS. 15A and 15B or FIGS.  
 17-21 so long as that member is not a portion of a supporting frame.  
  It is to be understood that the above described embodiment of the invention is merely illustrative of the principles thereof and that numerous modifications and embodiments of the invention may be derived within the spirit and scope thereof, such as by cantilevering balcony floor slabs off the end bearing wall slabs of the structure.  
 What is claimed is:  
  1. A method of constructing a self-supporting building unit which includes at least a first pair of opposed upstanding spaced apart substantially planar concrete wall slabs, each having a top portion, an opposed bottom portion, a pair of opposed end portions, and a pair of opposed side portions; and a first substantially flat planar concrete floor slab having a top portion, an op-