On the Constraint Factor of Welded Beam Knees

Lately in the connection of beam knees, welding has been taking the place of rivetting. But as the basis of the design of their type or size, we have no theoretical standard but only the customary practices or experiences. So there are some questions about the propriety of the plane application of the type and size of the rivetted knees to the welded ones.As the first step of the research of this problem, the author studied here about the so-called “constraint factor” of the welded beam knees in the elastic range.After the theoretical analysis of the “constraint factor” in an idealized condition, the author has looked experimentally for its value “β” of simple welded knees of common type, from the bending tests of four structural specimens having different sizes of knee, and gained β_??_0.85 regardless of their sizes, which is pretty larger value than usualy accepted.From these results it is concluded that, the welded knees are more effective to the strength and weight saving than the rivetted ones, and we can reduce the dimensions of the knees or stiffeners from the present values, and that we shall be able to improve the type of the knees to more effective one suitable to the welded knees.