Numerical Studies on the Buckling Resistance of Prestressed Stayed Columns

Abstract

The structural behaviour of prestressed stayed columns is investigated through nonlinear finite element modelling. The models were developed using the commercial software ABAQUS and validated against a series of recently conducted experiments. The sensitivity of the load-carrying capacity to the geometry of the stayed column, the initially applied prestress level within the stays and the initial global imperfection is investigated through parametric studies. It is found that there is a substantial increase in load-carrying capacity with increasing cross-arm length, provided the critical buckling mode remains symmetric. Once the critical buckling mode becomes antisymmetric, mode interaction becomes significant and the load-carrying capacity reaches a plateau and the component generally becomes more sensitive to imperfections. It is also found that the relative level of initial prestress required to maximize the load-carrying capacity of a given stayed column tends to reduce with increasing cross-arm length.

A full scale experimental study of prestressed stayed columns

“…This trend was also reported from numerical parametric studies by Osofero et al [23] but not so clear in the current tests.…”

“…Relationships between load and lateral deformations were proposed in addition to experimental studies on stayed column [11] 1984 Plane single cross-arm 0.81 E, N A series of tests were performed and compared with FE procedure which was developed in this study [12] 1985 --A Analytical studies to distinguish between buckling modes were performed [13] [18][19][20] 2010 Single cross-arm 3.05 N The issue of the true optimal prestress for stayed columns was examined through proposed structural optimisation indicators involving both instability and material quantity measures using FE simulations [21] 2012 Plane single cross-arm 2.8 E, N 18 full scale tests were performed Above experiments were used for validating FE simulation [22] 2013 Plane single cross-arm 2.9 N, A Numerical sensitivity study was performed to find out effect of cross-arm length on the load The sensitivity of the load carrying capacity to the geometry of the stayed column, the initially applied prestress level within the stays and the initial global imperfection was investigated numerically General design procedure for prestressed stayed columns with a single cross-arm system was proposed. (see Section 5) [23,24] * E: Experimental, A: Analytical and N: Numerical, Unit is in m. displacements at both ends and all other transducers were used to measure lateral displacements at every 1500 mm segments. Fig.…”

Experimental study of critical and post-buckling behaviour of prestressed stayed columns

“…w 0,1/4 ≈ w 0,3/4 b w 0,1/2 , all the triggered buckling modes in the experiments were those predicted by linear analysis for the respective geometries and prestress levels (see the final columns in Tables 4-7). More detailed numerical studies of the imperfection sensitivities of prestressed stayed columns have been conducted in [13,17,23].…”

Stability of prestressed stayed steel columns with a three branch crossarm system

“…This implies that the critical buckling load is less than 8% of the yield load. Moreover, in actual experimental studies of stayed columns, even though the buckling load of the column system is considerably enhanced due to the prestressed stay system, it has been demonstrated quite conclusively for practical arrangements [16,14,17,4] that elastic behaviour is (almost) exclusively observed. Even if material yielding is detected, it is only observed at deformation levels that are well beyond those at the ultimate load.…”

“…Prestressed stayed columns are by their very nature constructed from highly slender elements. Hence, geometrically nonlinear elastic analyses have been demonstrated to be sufficiently accurate given that yielding tends to occur significantly after the ultimate load capacity is reached [16,17]. Hence, in the current work, only geometrically nonlinear elastic analyses are conducted and the consideration of more stocky main column elements is left for the future.…”