Results of TLMRC research on X-bracing strength in lattice transmission towers

Abstract

END CO NDlTiONS Concentric @ Both Ends Normal Framing Eccentricity @ One End 8 Concentric @ Other End Normal Framing Eccenblclty @ Both Ends UnrestrainedAgalnst Rotation @ Both Ends Partially Restrained Against Rotation @ One End 8 Unrestrained @Other Robert Nickerson -Sverdrup Technology TLMRC, Haslet Texas CURVd Ur RANGE EFFECTIVE RATIO (KUr) NO. SLENDERNESS 1 o 5 UR (120 K U r = U r 2 0 5 UR 120 KUr = 30 + 0.75 Ur 3 0 (120 K V r = 6 0 + 0 . 5 U r 4 1 2 0 5 UR (200 K U r = Ur 5 120 5 L/R 5 2 2 5 KUr = 26.6 + 0.762 U I ntrduction Partially Restrained Agains 6 Rotation @ Both EndsTension/compression X-bracing is the most common type of bracing used to resist lateral load in transmission towers. The strength of a compression X-brace member is influenced by many factors including end restraint, end eccentricity, slenderness ratio (U), and the intermediate support offered by the tension member. 120 5 UR 5250 KUr = 46.2 + 0.615

Study on the influence of restraint stiffness of main material on the compression stability bearing capacity of cross-bracing in transmission tower

“…As early as 1924, the NBS of USA carried out the test of single angle steel, and then the experiment of 111 groups of cross-bracing was conducted by the EPIR of USA. Guoyi Nie [1] analyzed the influence of the connection of tie rod and single bolt on the bearing capacity of cross-bracing based on 111 groups of test data by the EPIR; Cannon DD [2] et al tested the bearing capacity of the cross-bracing of unequal angle steel and equal angle steel through two-dimensional frame. With the development of science and technology, Young Ben [3] , N. Prasad [4] , Hongnan Li [5] and others introduced the finite element model to conduct research, compared the data with specification, and put forward new design methods; Y Chen [6] , Zuyan Shen [7] , Shaofan Chen [8] and others studied the influence of different factors on the bearing capacity of cross-bracing through theoretical derivation, and put forward the proposed formulas.…”