unbraced length

unbraced length

The distance between ends of a structural member (such as a column) which are prevented from moving normal to the axis of the member, by bracing, by floor slabs, etc.
References in periodicals archive ?
where E is the modulus of elasticity of steel, [F.sub.y] is the yield strength of steel, K is the effective length factor, L is the laterally unbraced length of the member, r is the radius of gyration of the member, and [F.sub.e] is the elastic buckling strength given by (3).
Results also demonstrate that the high biaxial flexural strength of flanged and plain cruciform members enables maintenance of a stable flexural resistance across a large range of unbraced length. This is due to the ability of flanged and plain cruciform to resist lateral-torsional buckling, allowing development of efficient plastic resistance, over longer unbraced lengths when compared to conventional shapes.
The commentary also claims that torsional buckling is an uncommon mode of failure in doubly symmetric compression members without slender elements, except in cases where torsional unbraced lengths are significantly greater than the weak-axis unbraced lengths and in the case of doubly symmetric members.
Additional inputs to the program include unbraced lengths, effective length factors, material properties, and design loads (axial load and biaxial flexure).
Figure 3 shows the ratio of the torsional buckling resistance to flexural buckling resistance of each of the three sections at various unbraced lengths. In the case of these three cases, the torsional buckling resistance is typically greater than that of the flexural buckling resistance at low slenderness.
The results for axial and flexural resistance at different unbraced lengths ranging from 10 feet (3.33 m) to 40 feet (13.3 m) are shown in Figures 5-8.
where [l.sub.e] = effective length (1.44*[l.sub.u] + 3d for cantilever beam with concentrated load at free end); d = specimen height (depth); b = specimen width (or flange width of I-joist); [l.sub.u] = unbraced length or gage length of specimen.
However, further research to measure the CBLs of the full range of composite wood I-joist geometries, unbraced lengths, and loading conditions is needed before a modified design specification can be recommended.
Secondary or redundant bracing members are used to provide intermediate support to the primary members to reduce their unbraced length and increase their load carrying capacity [2].
where [l.sub.e] = effective length; d = specimen height; b = specimen width; [l.sub.u] = unbraced length or gage length of specimen.
Further research including a more comprehensive study of different unbraced lengths and loading conditions related to SCL materials should be conducted before specific changes to the wood design equations are proposed.