基于等效结构法的挂篮结构力学精细计算

李仁强

摘要： 挂篮是预应力混凝土连续梁或连续刚构桥施工的一种常用走行式支架及模板设备，建立合适的挂篮施工力学计算模型是确保挂篮施工安全及线形精准监控的基础。尽管可以采用三维杆件有限元法或简化的结构力学计算方法实现挂篮力学计算，但也经常容易出现计算模型选取未能真实反映挂篮的实际受力特征而导致的部分构件实际变形过大的现象，给桥梁线形及安全控制带来不利影响。本文在对挂篮进行结构受力特征分析的基础上，采用等效结构法将空间的挂篮结构等效成若干个平面杆件有限元模型，并借助RBCCE等相关BIM软件和力学分析软件便捷实现挂篮的力学计算，建模计算能够很好地反映挂篮结构的实际受力特征，实现挂篮结构计算简单化、高效率和标准化，并有利于预应力混凝土连续梁或连续刚构桥悬臂施工BIM技术的深化应用。

Abstract： The hanging basket is a commonly used walking bracket and formwork equipment for the construction of prestressed concrete continuous beams or continuous rigid frame bridges. Establishing a suitable mechanical calculation model for the hanging basket construction is the basis for ensuring the safety of the hanging basket construction and the precise linear monitoring. Although three-dimensional bar finite element method or simplified structural mechanics calculation method can be used to achieve the calculation of the hanging basket mechanics， it is often prone to the fact that the selection of the calculation model fails to truly reflect the actual stress characteristics of the hanging basket and cause the actual deformation of some components to be too large. The phenomenon has an adverse effect on the alignment and safety control of the bridge. In this paper， based on the structural force analysis of the hanging basket， the equivalent structure method is used to make the space hanging basket structure equivalent to a number of planar finite element models， and the related BIM software such as RBCCE and mechanical analysis software is used to realize the mechanical calculation of the hanging basket conveniently. The modeling calculation can well reflect the actual stress characteristics of the hanging basket structure， realize the simplification， high efficiency and standardization of the hanging basket structure， and is beneficial to the deepening application of BIM technology in cantilever construction of prestressed concrete continuous beam or continuous rigid frame bridge.

關键词： 桥梁；挂篮；计算；施工

Key words： bridge；hanging basket；calculation；construction

中图分类号：U445 文献标识码：A 文章编号：1006-4311（2018）21-0120-04

0 引言

在预应力混凝土连续梁或连续刚构桥悬臂施工方法中，挂篮是一种重要的可走行支架和模板，主要由主构架、外模、内模、底模、走行系统及悬吊系统构成，其关键受力构件有主构架、前上横梁、前下横梁、后下横梁、外滑梁、内滑梁、前吊杆及后吊杆等。确保挂篮施工安全的关键在于建立起反映挂篮结构力学行为特征的计算模型，以得到各关键受力构件的受力计算结果。工程上，虽然可以采……