Plane lattice hollow concrete slab and cross arm brace

Abstract

In order to obtain a plane lattice hollow concrete slab having a high workability and a high sound insulating property, and a cross arm brace used in the plane lattice hollow concrete slab, the plane lattice hollow concrete slab comprises a light weight body 5 buried in a small space 4 which is partitioned on a grid by upper reinforcing bars 3 a and 3 b and lower reinforcing bars 2 a and 2 b positioned on a grid in a slab. The light weight body is a solid-core or a hollow light weight ball body. The light weight body has a diameter which passes through a top surface of the small space and which does not pass through a side surface of the small space. The light weight body is fixed to a predetermined position by a cross arm brace which is positioned on the upper reinforcing bar. The cross arm brace comprises at least two auxiliary reinforcing bars positioned in parallel between upper reinforcing bars adjacent to each other, and a plurality of units each of which is fixed downwardly on the auxiliary reinforcing bar. Each of the units is inserted into a small space formed by upper reinforcing bars which are positioned on a grid. A light weight ball body is fixed to a predetermined position of the small space.

1 . A plane lattice hollow concrete slab comprising a light weight body buried in a small space which is partitioned on a grid by an upper reinforcing bar and a lower reinforcing bar positioned on a grid in a slab, wherein: 
 said light weight body is a solid-core or a hollow light weight ball body;    said light weight body having a diameter which passes through a top surface of said small space and which does not pass through a side surface of said small space; and    said light weight body being fixed to a predetermined position by a cross arm brace which is positioned on said upper reinforcing bar.    
   
   
       2 . A plane lattice hollow concrete slab as claimed in  claim 1 , wherein a volume ratio of said small space to said light weight ball body is from 10% to 50%.  
   
   
       3 . A cross arm brace for a plane lattice hollow concrete slab, wherein: 
 said cross brace comprises at least two auxiliary reinforcing bars positioned in parallel between upper reinforcing bars adjacent to each other, and a plurality of units each of which is fixed downwardly on said auxiliary reinforcing bar;    each of said units being inserted into a small space formed by upper reinforcing bars which are positioned on a grid; and    a light weight ball body being fixed to a predetermined position of said small space.    
   
   
       4 . A cross arm brace for a plane lattice hollow concrete slab as claimed in  claim 3 , wherein each of said units is an endless frame reinforcing bar which is bent to a saddle shape.  
   
   
       5 . A cross arm brace for a plane lattice hollow concrete slab as claimed in  claim 4 , wherein each of said units has a leg portion which is bent to an outer side.  
   
   
       6 . A cross arm brace for a plane lattice hollow concrete slab as claimed in  claim 3 , wherein: 
 each of said units comprises holding reinforcing bars which are bent so as to form a valley, said holding reinforcing bars being positioned one after the other with inclination; and    both ends not being connected to each other in each of said holding reinforcing bars.