﻿ 基于梁格法的小半径钢筋混凝土弯箱梁桥空间受力特性分析 Analysis of Spatial Force Characteristics of Small Radius Curved Concrete Box Girder Bridge Based on Grillage Method

Hans Journal of Civil Engineering
Vol.06 No.05(2017), Article ID:21723,8 pages
10.12677/HJCE.2017.65052

Analysis of Spatial Force Characteristics of Small Radius Curved Concrete Box Girder Bridge Based on Grillage Method

Borui Peng1,2, Dan Tang2*

1Changsha Planning & Design Institute Co., Ltd., Changsha Hunan

2School of Civil Engineering, Central South University, Changsha Hunan

Received: Jul. 26th, 2017; accepted: Aug. 9th, 2017; published: Aug. 17th, 2017

ABSTRACT

Curved box girder bridge is beautiful, can adapt to and improve the road linearity. In recent years, it has been widely used in urban bridges. But the force of curved box girder bridge is complex, it needs to use the spatial analysis method for analysis. In this paper, the full-bridge grid model was established by MIDAS/Civil based on grillage method, and the spatial force characteristics of the small radius curved box girder were analyzed, and the displacement and bearing reaction characteristics under the load were studied. By analyzing the calculation results of the space model, it can be seen that there are obvious bending and torsional coupling effects of the small radius curved box girder structure, which can cause the torsion of the cross section of the bending box and the nonuniformity of the bearing reaction. However, there is an effective reduction of the nonuniformity of the bearing reaction by bearing eccentricity.

Keywords:Curved Box Girder Bridge, Bending and Coupling, Grillage Method, Bearing Eccentricity

1长沙市规划设计院有限责任公司，湖南 长沙

2中南大学土木工程学院，湖南 长沙

Copyright © 2017 by authors and Hans Publishers Inc.

1. 引言

(a) 实际结构 (b) 等效结构

Figure 1. Equivalent grillage schematic diagram

2. 影响弯箱梁桥受力的因素

2.1. 荷载因素

2.2. 曲线半径和圆心角

2.3. 支承因素

1) 在一联连续梁两端的桥台或盖梁处采用两点或多点支承的支座，可有效地提高主梁的横向抗扭性能，保证其横向稳定性。

2) 中间墩的支承的合理选用应考虑其平面上的圆曲率半径、跨径及预应力效应的影响。

3) 弯梁桥的支承形式应根据曲率半径的大小、上下部结构的总体布置决定，选用对结构受力有利的支承方式，并由此决定全桥的力学计算图示，确定全桥的内力分布。

2.4. 预设支座偏心的影响

3. 工程实例与计算分析

3.1. 有限元模型的建立

Figure 2. Planar layout of small radius curved concrete box girder bridge

Figure 3. Cross section of midspan (unit: cm)

Figure 4. Full bridge model

Figure 5. The division of longitudinal cross section

Figure 6. Support node number

3.2. 计算结果与分析

Figure 7. The vertical displacement of constant load

Figure 8. The vertical displacement of land load

Figure 9. The vertical displacement of uneven settlement

Figure 10. The vertical displacement of temperature

Table 1. Radius of small radius curved box girder (to be down, unit:mm)

Table 2. Support reaction table

4. 结论

1) 小半径弯箱梁桥对周围地形适应性高，外形美观，受力满足要求，作为城市立体交通中的匝道桥，体现了桥梁设计“美观、安全、适用”的理念。

2) 在不同荷载的作用下，同一截面内外侧挠度最大偏差达14.87 mm，弯箱梁发生了扭转，这表明小半径混凝土弯箱梁结构存在明显的弯扭耦合效应，可引起箱梁截面的扭转。

3) 在四种工况作用下，桥梁内外侧支座反力最大差值为2008.4 KN，表明弯箱梁的弯扭耦合作用会引起支座反力不均匀的现象。

4) 支座偏心距对桥两端支反力影响较大，随着偏心距增大，梁端内、外侧支座反力有平衡的趋势,对中间墩的支座反力影响较小。

Analysis of Spatial Force Characteristics of Small Radius Curved Concrete Box Girder Bridge Based on Grillage Method[J]. 土木工程, 2017, 06(05): 439-446. http://dx.doi.org/10.12677/HJCE.2017.65052

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