Abstract: A trailer incorporating the features of the subject invention has a wheel assembly near the trailing end and a scissors-type lift mechanism near the leading end, with a fulcrum support intermediate the wheel assembly and lift mechanism. The method of lowering the trailer to the ground includes the steps of lowering the leading end of the trailer to the ground with the lift mechanism causing the trailing end to pivot about the fulcrum support into engagement with the ground, further raising the leading end of the trailer to raise the fulcrum support off the ground, removing the fulcrum support, and finally lowering the leading end of the trailer until the entire trailer is in flat engagement with the ground.

Abstract: A structural element having a fire rating of approximately two hours when tested with the standard time-temperature curve established by the American Standards for Testing Materials, said element including prestressed concrete joists each having a plate-like body portion and reinforced support ledges, each ledge has a nailing strip molded adjacent the bottom thereof and each nailing strip including a penetratable area formed internally adjacent thereof, a plurality of sheets of material disposed adjacent the ends of said ledges, each sheet of material forming a butt joint with an adjacent sheet which extends longitudinally along one of said ledges, channel-shaped members disposed along each butt joint intermediate said ledge portion and said sheets and attachment means for attaching said channel-shaped members to the nailing strips and, also, for attaching sheets of material to said nailing strips and channel-shaped members whereby said sheets of material are secured to the joist while preventing undesirable