混合钢种工字形叠合梁抗弯承载力研究

STUDY ON FLEXURAL CAPACITY OF HYBRID I-SHAPED LAMINATED STEEL GIRDER

锅炉钢架的主要承重构件大板梁截面尺寸巨大,通常由上下层工字梁叠合而成。探讨对此类叠合梁采用钢种混合的可行性,即下翼缘板采用较高强度钢,而其他板件均采用较低强度钢。首先定义混合钢种工字形叠合梁受弯过程中的四个特征弯矩并进行理论推导,然后分析截面尺寸、钢种强度比对抗弯承载力的影响,得到合理的板件尺寸和钢种强度比。研究发现,混合钢种工字形叠合梁可充分发挥翼缘板和腹板的钢材强度,保证足够安全储备的同时,可明显提高抗弯承载力,减轻结构自重。

Plate girder with huge size which plays a role of the main bearing component in the boiler steel frame, are usually laminated by two floors of I-shaped beam vertically. This paper studied the practicability of the kind of laminated girder made with steel of different strength, which bottom flange was made with higher strength steel but the others with lower strength steel. Firstly, definition and theoretical derivation were conducted on four characteristic moments in the bending process of hybrid I-shaped laminated steel girder,then analyzed how sectional dimensions and steel yield strength ratio influence its flexural capacity to get applicable member sizes and steel yield strength ratio. The results showed that hybrid I-shaped laminated steel girder obviously could enhance the flexural capacity and reduce the deadweight with enough emergency capacity,and make full use of both the flanges and steel strength of webs.