GAITHERSBURG, Md. (AP) - Early tests on steel beams from the World Trade Center show they generally met or were stronger than design requirements, ruling them out as a contributing cause of the collapse of the towers, federal investigators said Wednesday. Engineers with the National Institute of Standards and Technology have conducted preliminary tests on some of the 236 pieces of steel from the wreckage, said Frank Gayle, who is leading NIST's review of the steel. The tests found that, typical for construction steel used in the 1960s when the World Trade Center was erected, the steel beams exceeded requirements...