# 预制大箱梁桥静载试验中分布式光纤传感技术的应用Application of Distributed Optical Fiber Sensing Technology in Static Load Test of Precast Large Box Girder Bridge

DOI: 10.12677/HJCE.2018.76111, PDF, HTML, XML, 下载: 468  浏览: 1,656  科研立项经费支持

Abstract: Taking the Hangzhou Bay Cross-Sea Bridge Hangzhou-Ningbo Expressway connecting line highway project as the background, the measuring point arrangement of strain cable and digital strain sensor in the load test of the main line 28-span prefabricated large box girder bridge is introduced, which is measured under static load conditions. The strain distribution of the whole bridge and the strain value of the mid-span section are measured under the static load condition, and the theoretical modeling analysis of the bridge is tested, comparing the theoretical results with the measured values. The research shows that the distributed optical fiber sensing technology test data is not only consistent with the actual measurement of the strain gauge, but also the continuous strain distribution of the beam bottom. The surface distributed optical fiber sensing technology has high application value in bridge detection.

1. 引言

2. 技术原理

2.1. 基本原理

Figure 1. Schematic diagram of distributed optical sensing technology

$\Delta f={C}_{11}×\Delta \epsilon +{C}_{12}×\Delta T$ (1)

2.2. 系数标定

Figure 2. Brillouin frequency/strain coefficient frequency/temperature coefficient

2.3. 数据处理方法

$\Delta {f}_{1}={C}_{11}×\Delta {\epsilon }_{1}+{C}_{12}×\Delta T$

$\Delta {f}_{2}={C}_{22}×\Delta T$ (2)

$\Delta {\epsilon }_{1}=\frac{\Delta {f}_{1}-\frac{\Delta {f}_{2}}{{C}_{22}}×{C}_{12}}{{C}_{11}}$ (3)

3. 工程介绍

3.1. 工程概况

Figure 3. Bridge site inspection map

3.2. 施工加装

Figure 4. Main line 28th sensor installation diagram (upper elevation, bottom section)

Figure 5. Sensor and sensor cable installation physical map

3.3. 加载工况

(注：分级加载，一级：1、2、3、4二级：5、6、7、8)

4. 试验与结果

4.1. 模型分析

Figure 7. Main line 28th bridge model interface diagram

4.2. 数据分析

4.2.1 . 1号中载应变

Figure 8. Distributed fiber, grating, strain gauge strain comparison results in sensor No. 1

Table 1. Load Strain Comparison of No. 1 Sensor B Section

4.2.2 . 2号中载应变

Figure 9. Distributed fiber, grating, strain gauge strain comparison results in sensor No. 2

Table 2. Load Strain Comparison of No. 2 Sensor B Section

4.2.3 . 1号偏载应变

Figure 10. Distributed fiber, grating, strain gauge strain comparison results in sensor No. 1

Table 3. Offset load Strain Comparison of No. 1 Sensor B Section

4.2.4 . 2号偏载应变

Figure 11. Distributed fiber, grating, strain gauge strain comparison results in sensor No. 2

Table 4. Offset load Strain Comparison of No. 2 Sensor B Section

5. 结论

1) 成功的将分布式光纤传感技术应用于混凝土预制大箱梁桥的静载试验中，结果表明该技术能够测量桥梁的整体应变分布情况，实测曲线和传统应变传感器基本吻合。

2) 通过对比分布式光纤、光纤光栅、应变计的实测值可知，分布式光纤传感技术具有较高的应变测量精度，满足实际测试要求。

3) 分布式光纤传感技术采用的光缆结构简单，应变传递性好，测量精度高，价格便宜，不仅适合用于传统的静载检测试验，更适合长距离、大范围的结构健康监测。

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