Precast concrete beam element and methods of making and installing same

Abstract

An improved precast concrete beam element, useful as a continuous bearing structural foundation member supporting wall and floor slab loads in soil, has a unique shape and includes a bearing surface for spreading vertical loads into the soil and a wall section having a height sufficient to place the bearing surface at a specified bearing depth in the soil. Optionally, the precast beam element also includes a formed-in notch to serve as a block ledge to facilitate weathertight wall installation. By integrating both the slab form edge and the wall ledge, the beam element eliminates the need for field forming. The beam element is manufactured offsite in a mold capable of changing dimension to cast elements with differing bearing heights and differing wall thicknesses as soil and loading conditions require. Installation of the beam element involves simple suspension of the beam element above an excavated trench such that a gap is formed between the bottom and sides of the trench and the surfaces of the beam element. As the beam element is suspended above the trench, a flowable fill material is poured into the trench to fill the gap. When the flowable fill material hardens, the beam element is locked into place, achieving full bearing and lateral stability.

What is claimed is:  
     
         1 . A precast structural beam element, comprising: 
 (i) a straight back face;    (ii) a top surface;    (iii) a bottom surface;    (iv) a front face; the front face having: 
 a first upper surface extending perpendicularly and downwardly from the top surface and being parallel to the back face;  
 a second upper surface which slopes downwardly and inwardly from the first upper surface;  
 a middle surface which is parallel to the back face and which extends downwardly from the second upper surface;  
 a first lower surface which slopes downwardly and outwardly from the middle surface; and  
 a second lower surface which is parallel to the back face and which extends downwardly from the first lower surface and perpendicularly to the bottom surface; and  
 (v) first and second opposite side faces disposed between the back and front faces and between the top and bottom surfaces.  
   
     
     
         2 . A beam element according to  claim 1 , wherein the top surface of the beam element has a notch formed therein which extends lengthwise along the top surface and/or the middle surface of the front face has a dapped surface formed therein.  
     
     
         3 . A method of making the beam element of  claim 1 , comprising the steps of: 
 ( 1 ) providing a mold comprising: 
 (a) a longitudinally movable lateral side rail having an inner wall for forming the top surface of the beam element;  
 (b) an opposite fixed lateral side rail having an inner wall for forming the bottom surface of the beam element;  
 (c) a first longitudinal side rail disposed between the movable and fixed lateral side rails and having an inner wall for forming the first side face of the beam element;  
 (d) an opposite second longitudinal side rail disposed between the movable and fixed lateral side rails and having an inner wall for forming the second side face of the beam element;  
 (e) an infill plate disposed between the inner walls of the lateral and longitudinal side rails such that an upper face of the infill plate and the inner walls of the lateral and longitudinal side rails define a mold cavity, the upper face of the infill plate being disposed to form the front face of the beam element; and  
 (f) one or more dowel rods projecting upwardly from the mold cavity;  
   (2) filling the mold cavity with a flowable fill material;    (3) allowing the flowable fill material to harden to form the beam element; and    (4) removing the beam element from the mold cavity.    
     
     
         4 . A method according to  claim 3 , wherein the inner surface of the longitudinally movable lateral side rail has a configuration so as to form a notch which extends lengthwise along the top surface, and/or the upper face of the infill plate has a configuration so as to form a dapped surface in the middle surface of the front face.  
     
     
         5 . A method according to  claim 3 , wherein the flowable fill material is concrete.  
     
     
         6 . A method for installing the beam element of claim I into the ground, comprising the steps of: 
 (1) providing an excavated trench having a bottom surface, inner wall surfaces and an open top surface;    (2) suspending the beam element above the trench so that a bottom gap is formed between the bottom face of the beam element and the bottom surface of the trench and a side gap is formed between the inner walls of the trench and the front, back and side faces of the beam element;    (3) pouring a flowable fill material into the trench so as to fill the bottom gap and at least a portion of the side gap; and    (4) causing the poured material to harden.    
     
     
         7 . A method according to  claim 6 , wherein the flowable fill material is concrete or grout.  
     
     
         8 . A method according to  claim 6 , wherein the top surface of the beam element has a notch formed therein which extends lengthwise along the top surface and/or the middle surface of the front face has a dapped surface formed therein.  
     
     
         9 . A method according to  claim 6 , further comprising after step (4), the step (5) of installing a second beam element of  claim 1  in accordance with the method of  claim 6 , the second beam element being installed adjacent to the beam element installed according to the method of  claim 6 .  
     
     
         10 . A method for forming a floor slab, comprising the steps of: 
 (1) installing the beam element of  claim 1  in accordance with the method of  claim 6;     (2) providing a floor slab-forming location for forming the floor slab, the location being adjacent to the beam element such that the back face of the beam element will serve as an edge form during casting of the floor slab; and    (3) casting the floor slab in said location.    
     
     
         11 . A method according to  claim 10 , wherein, in the beam element used in step (1), the top surface of the beam element has a notch formed therein which extends lengthwise along the top surface and/or the middle surface of the front face has a dapped surface formed therein.  
     
     
         12 . A method of forming a wall slab, comprising the steps: 
 (1) installing the beam element of  claim 1  in accordance with the method of  claim 6;     (2) providing a wall slab-forming location for forming the wall slab, the location being adjacent to the beam element such that the top face of the beam element will serve as an edge form during casting of the wall slab; and    (3) casting the wall slab in said location.    
     
     
         13 . A method according to  claim 12 , wherein, in the beam element used in step (1), the top surface of the beam element has a notch formed therein which extends lengthwise along the top surface and/or the middle surface of the front face has a dapped surface formed therein.