Mechanical Performance Analysis and Profile Optimization of Pre-bent Steel-concrete Composite Straddle Monorail Track Beams

Abstract

[Objective] Most conventional straddle monorail track beams utilize a profile form with 850 mm width. In response to the urban rail transit construction demands of the third and fourth-tier cities in China, relevant enterprises propose a profile form with 1 250 mm width for straddle monorail train. To address the special requirements of the new straddle monorail train, it is necessary to study the mechanical performance and profile form of the track beams. [Method] A numerical simulation method is employed to establish a pre-bent steel-concrete composite track beam model. Based on the conventional track beam profile form, a preliminary profile form of 1 250 mm wide pre-bent steel-concrete composite straddle monorail track beam is proposed. The mechanical performance of the profile under different load combinations is analyzed, and the profile parameters of the preliminary profile form are optimized with the goal of minimizing steel consumption. [Result & Conclusion] With the increase of steel box beam top plate thickness, the maximum normal stress of steel box beam upper flange decreases. When the steel box beam bottom plate thickness increases, the maximum normal stress of steel box beam lower flange decreases. With the increase of auxiliary plate thickness, the maximum shear stress of steel box beam auxiliary plate decreases. Under the most unfavorable load working condition combinations, the stiffness and strength of the proposed track beam preliminary profile form both meet the allowable limit of the specifications. The optimized top plate thickness, auxiliary plate thickness, and bottom plate thickness are 16 mm, 20 mm and 16 mm, respectively, contributing to approximately 29.89% reduction in steel surface area.

Keywords

• straddle monorail
• pre-bent steel-concrete composite track beam
• mechanical performance