by the present invention 39 s tight tolerance fabrication gives the reinforced concrete member much greater ductility than is present in the prior art these consistently exact dimensions improve the reliability of the reinforced concrete structure and permit it to withstand violent earthquake forces the more exact dimensions of the grids of the present invention provide for the use of automated fabrication and assembly methods they thus reduce the time required for erection as well as for the connection of the cages and precast members of the present invention the increase ductility of the structural members of the present invention makes them more resistant to lateral seismic forces thus the members can be constructed utilizing significantly less concrete and steel while maintaining the same earthquake resistance referring now to fig3 a generally rectangular grid 60 for use in the formation of girders 130 best shown is fig1 and 15 of the present invention is illustrated the girder grid 60 comprises a plurality i e three first or vertical wire members 62 disposed perpendicularly to a plurality i e four of second or horizontal members 64 as in the column grids 40 pre positioned wire ties 46 are formed at the interior corners of intersecting wire members 62 and 64 and provide like benefits referring now to fig3 a the intersection 66 of two wire members 62 and 64 having a pre positioned tie 46 attached thereto is illustrated a weld joint preferably interconnects the two wire members 62 and 64 such welded construction is preferably utilized in both the column grids 40 of fig2 and the girder grids 60 of fig3 because of the high strength union.