Experimental and analytical studies on the lateral instability of UHPFRC beams lifted by cables

Abstract

The outstanding behavior of Ultra-High Performance Fiber-Reinforced Concretes (UHPFRC) enables the development of thin precast beams with a reduced material consumption but meeting at the same time the required shear and flexural performances. However, the arisen slenderness make these elements prone to instability failure that for precast structures can occur mainly during construction stages, like lifting. Tests of beams lifted by cables are rare and were not reported for elements made of UHPFRC. Then, the present study aims to provide such experimental data and an analytical solution to predict the behavior of UHPFRC beams during the lifting phase. The cables were inclined to be attached to a crane hook and the beam subjected to a vertical load at midspan to induce lateral instability. The displacements were measured with a robotic total station. Furthermore, the analytical solution was developed based on the Rayleigh-Ritz method. From the results, the UHPFRC beams failed by instability with a load capacity 3.7 times smaller than the peak flexural load. Also, the analytical solution predicted the instability load with great accuracy.