condition is particularly aggravated when a weak clay stone or other rock type occurs within approximately 5 to 10 feet of the floor line in such cases the vertical compressive forces from the pillars are translated to horizontal forces along these weak strata causing floor rupture and heave where a truss structure is to be employed for precluding floor heave then the truss brackets will be made of appreciably heavier material likewise the tie rods and anchor bolts used will be of substantially heavier material fig5 illustrates employment of the present invention 39 s truss assembly in a floor installation as well as in roof installation but with the brackets spread apart a greater distance so as to place as much of the floor in increased compression as possible thus truss assembly 10 includes depending anchor bolts which are each angulated outwardly generally in 45 u00b0 relationship relative to the vertical and are being tensioned by respective nuts 17 bearing upon bracket plate 16 of respective truss bracket 11 the anchor ends of the bolts are secured in place in the rock formation beyond the rib line of the pillars this so that the compressive forces set up by the pillars can be utilized in the retention of the bolts in the rock strata the horizontal tie rods 13 are placed under tension by the tightening down of nuts 20 and 21 this.