Buckling behavior analysis of prestressed CFRP-reinforced steel columns via FEM and ANN

Effects of un-bonded deviators on the out-of-plane buckling of steel H-beams pre-stressed by a straight tendon cable

This paper presents a novel approach for determining the critical lateral-torsional buckling loads of beams subjected to arbitrarily transverse loads. This new method is developed based on the clas...

Calculation of Critical Lateral-Torsional Buckling Loads of Beams Subjected to Arbitrarily Transverse Loads

Despite appropriate design of girder under bending and shear, the deflection of long steel girders usually exceeds the allowable range, and therefore the structural designers encounter challenges in this regard. Considering significant features of the cables, namely, low weight, small cross section, and high tensile strength, they are used in this research so as to control the deflection of long girder bridges, rather than increasing their heights. In this study, theoretical relations are developed to calculate the increase in pre-tensioning force of V-shaped steel cables under external loading as well as the deflection of steel girder bridges with V-shaped cables and different support conditions. To verify the theoretical relations, the steel girder bridge is modeled in the finite element ABAQUS software with different support conditions without cable and with V-shaped cables. The obtained results show that the theoretical relations can appropriately predict the deflection of girder bridge with V-shaped cables and different support conditions. In this study, the effects of the distance from support on the deflection of mid span are studied in both simply supported and fixed supported girder bridge so as to obtain the appropriate distance from support causing the minimum deflection.

Controlling deflection of long steel I-shaped girder bridge using two V-shaped pre-tensioning cables

We develop a novel lateral–torsional buckling theory for pre-stressed (PS) steel H-beams with or without a deviator by using the total potential energy derived from the second order terms of semi-tangential rotations, the analytically derived exact solutions are presented and compared with the approximate solutions produced by the Ritz method and FEM. In this work, we particularly focus on the buckling characteristics of simple and cantilever PS beams under three loading conditions: initial tension only, compression, and quasi/semi-tangential moments. In addition, we demonstrate how these quasi- and semi-tangential moments are generated based on semi-tangential rotations. Furthermore, we verify that in-plane load distributions and spatial buckling loads under the conditions of a rectilinear cable with an un-bonded deviator are exactly the same as under the conditions of a rectilinear cable with a bonded deviator. Finally, a deviator’s effect on the buckling strengths of the PS system with double tendons under external loading is examined.

Lateral–torsional buckling of steel beams pre-stressed by straight tendons with a single deviator

Until now, there are no analytical solutions published of the lateral-torsional buckling (LTB) of the prestressed steel I-beams. In this paper, the symmetric and antisymmetric elastic LTB buckling performance of prestressed steel I-beams, with rectilinear tendons, under equal end moments has been examined. Firstly, a simplified mechanical model is put forward. Secondly, based upon the Euler-Beam model & the Kirchhoff-Plate model, the strain energy equation as well as the potential energy of the prestressed steel I-beam are derived in detail. Then the total potential equation and the differential equilibrium equations along with the boundary conditions are obtained. As a result, the analytical solutions of the symmetric and antisymmetric elastic LTB of prestressed I-beams are obtained, for the first time, and the correctness of the analytical solution of the critical moment of the symmetric buckling of the prestressed I-beam is verified by those simulated by using ANSYS. Finally, parameter analysis is carried out. It is found that: (1) the critical moment of the prestressed steel I-beam, with rectilinear tendons, under equal end moments can be determined by that of the symmetric buckling; (2) the critical prestressing force can be determined by that of the symmetric buckling or antisymmetric buckling depending on the relationship between the dimensionless eccentricity and its threshold value.

Wen-Fu Zhang

Papers

Symmetric and antisymmetric lateral–torsional buckling of prestressed steel I-beams