PCI eLearning Course T523: Girder Stability During Transport-Mast 1989, Lateral Stability Part 1

Mast 1989, Lateral Stability Part 1

Pdf Summary

This special report discusses the importance of lateral stability in prestressed concrete beams, particularly during handling and shipping. The report highlights the inadequacy of traditional lateral buckling formulas for addressing the unique cases of beams suspended on cables or springy supports. Part 1 of the report focuses on the lateral bending stability of beams when suspended from lifting loops, while Part 2 extends the analysis to beams supported on elastic restraint to rolling.<br /><br />The report provides equations for computing the factor of safety against lateral buckling instability. The factor of safety is determined by various parameters such as the initial lateral eccentricity, the height of the roll axis, the lateral stiffness, and the maximum permissible tilt angle of the beam. The report compares these equations to those provided in the PCI Design Handbook and presents a numerical example to demonstrate the proposed method.<br /><br />The report further discusses methods for improving the lateral stability of long beams, including moving the lifting points inward, raising the roll axis, increasing the modulus of elasticity, adding bracing, or modifying the beam cross-section. It emphasizes the effectiveness of moving the lifting points inward and provides a simple program to compute the factor of safety based on the distance of the lifting points from the beam's ends.<br /><br />The report concludes by discussing Part 2 of the report, which focuses on the analysis of lateral bending stability for beams supported on flexible supports. It outlines the logic of the program and provides a preview of the derivation of equations that will be presented in Part 2. Finally, the report includes a metric conversion section and references for further reading.

Keywords

lateral stability

prestressed concrete beams

handling and shipping

factor of safety

lateral bending stability

lifting loops

PCI Design Handbook

improving lateral stability

moving lifting points inward

flexible supports