30 32 the upper and lower webs 18 20 are secured to the parallel opposed flanges at weld lines w 1 w 2 w 3 and w 4 both the upper web 18 and the lower web 20 each contain one small opening located approximately mid length between longitudinal ends 16 16 u2032 and equal distance between lateral edges 14 14 u2032 where a short weld is placed along the edge of the opening to secure the steel core to the restraining webs 18 20 not depicted in fig1 this is the only place where the steel core 12 is connected to either of the webs 18 20 also depicted in fig1 are cutouts 38 40 at the longitudinal ends 39 of the upper web 18 the cutouts 38 40 facilitate the placement of the core stiffeners 42 44 to the steel core 12 as depicted in fig1 the cutouts 38 40 are fabricated into the longitudinal ends 19 21 of both of the upper and lower webs 18 20 as seen in fig3 and positioned atop the upper and lower webs 18 20 are slope stiffeners 33 34 35 36 that restrain the free longitudinal edge of the web slot 38 40 against deformation when a large load is applied to the core 12 the web slots 38 40 also preferably terminate in a radius u2018 r u2019 at the interior end of each slot 38 40 utilizing a radius as opposed to an orthogonal edge at the end of the slot reduces the potential.