简支斜交T梁桥跨中横向分布系数研究
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作者:王荣霞,吕沛熙
摘要 针对大宽跨比简支斜交T梁桥,应用MIDAS建立有限元模型,对其跨中横向分布系数进行了计算,分析其斜交角和宽跨比对跨中横向分布系数的影响规律。研究表明:在斜交角相同时,宽跨比越大,各主梁跨中横向分布系数分布得更加均匀,有利于桥梁整体受力;宽跨比相同时,随着斜交角的增大,各主梁的跨中横向分布系数分布变得越均匀,有利于桥梁跨中部分受力。对于大宽跨比简支斜交T梁桥,当斜交角小于30°时,跨中横向分布系数与正桥接近,误差在5%以内;在斜交角大于30°时,误差急剧增大,如果忽略斜交角影响,按正桥计算结果过于保守。
关 键 词 简支斜交T梁桥;横向分布系数;宽跨比;梁格法;斜交角
中图分类号 U441.3 文献标志码 A
The research about load transversal distribution of simple-supported skewed T-beam bridge
WANG Rongxia, [LU] Peixi
(School of Civil Engineering and Transportation, Hebei University of Technology, Tianjin 300401, China)
Abstract The regularity about the influence of skewed angle and width-span ration for load transversal distribution of high width-span ratio simple-supported skewed T-beam bridge has been analyzed in this article. Midas is applied to establish to finite element model and calculate the load transversal distribution midst the main beams. The research results are as follows: If the skewed angle is nailed, the higher width-span ration makes more average load transversal distribution midst main beams, which benefits the structural stress condition; If the width-span ratio is nailed, the higher skewed angle makes average load transversal distribution, which is better for structural stress condition; If the skewed angle is under 30°, the performance of load transversal distribution of high width-span ratio bridge is similar to that of the load transversal distribution of low width-span ration bridges, and the error between them is limited within 5% . If the skewed angel is over 30°, the error develops rapidly, and the load transversal distribution would become too conservative when skewed angle is ignored.
Key words simple-supported skewed T-beam bridge; load transversal distribution ; width-span ration; grillage analogy method; skewed angle
0 引言
S着我国桥梁建设的飞速发展,车辆交通需求日益增加,为满足交通线形和运行安全的要求,需要修建大量斜桥。其中,大宽跨比斜梁桥(宽跨比≥0.5的梁桥)在斜桥中占有较大比重[1]。有研究表明,因桥梁结构的空间受力特性,当其宽跨比较大时,其空间结构效应和传统的窄梁桥(宽跨比<0.5的梁桥)有着显著差别[2]。因此有必要开展对大宽跨比斜梁桥的理论研究,以满足日益增长的交通需求,提高此类结构的安全性。
此外,在大量已建的斜交桥中,最常采用装配式施工方法。这种具有多片主梁的桥梁结构在设计过程中,计算跨中荷载横向分布系数是其中一个很重要的环节,直接影响到主梁设计承载力大小和配筋数量,需要科学合理的设计理论来提供指导。但目前针对斜交梁桥跨中横向分布系数的相关研究较少,主要集中在小宽跨比斜交桥或者大宽跨比正交桥两类结构,如文献[3]研究了小宽跨比斜板桥的跨中横向分布系数与斜交角度关系,文献[4]提出了大宽跨比正交T梁桥跨中横向分布系数的计算方法,而对大宽跨比斜交梁桥的跨中横向分布系数的研究却未见报道。因此,本文针对大宽跨比斜交梁桥的跨中横向分布系数进行深入研究,可以弥补前人的不足,为该类结构设计提供科学的理论指导,具有重要的工程参考价值。
本文以一座标准跨径为30 m的简支斜交T梁桥为依据,通过建立Midas有限元梁格模型,分析了斜交角和宽跨比对跨中荷载横向分布系数的影响规律,对跨中横向分布系数的取值提出指导性建议。
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