﻿ 基于行波效应的矮塔斜拉桥抗震分析 Seismic Analysis of Low Pylon Cable-Stayed Bridge Based on Traveling Wave Effect

Hans Journal of Civil Engineering
Vol. 07  No. 05 ( 2018 ), Article ID: 26943 , 7 pages
10.12677/HJCE.2018.75088

Seismic Analysis of Low Pylon Cable-Stayed Bridge Based on Traveling Wave Effect

Yecheng Chen1, Qimeng Li2, Xiaobiao Jiang2

1Kunming Construction Quality and Safety Supervision and Management Center, Kunming Yunnan

2Civil Engineering and Architecture Faculty, Kunming University of Science and Technology, Kunming Yunnan

Received: Sep. 5th, 2018; accepted: Sep. 19th, 2018; published: Sep. 26th, 2018

ABSTRACT

The low tower cable-stayed bridge, also known as the partial cable-stayed bridge, is a combined bridge between the continuous rigid frame bridge and the conventional cable-stayed bridge. As a major highway bridge, the large-span low-rise cable-stayed bridge has a large investment and will cause huge economic losses once it is destroyed in the earthquake. Therefore, the seismic performance of long-span low-rise cable-stayed bridges should be fully studied. Taking a bridge as an engineering example, considering the geological conditions and topographic conditions of its location, the finite element model is established to analyze the elasto-plastic dynamics of the structure. Considering the traveling wave effect factors, the influence of the seismic response on the structure is discussed, and the corresponding laws are summed up.

Keywords:Low Tower Cable-Stayed Bridge, Seismic Response, Structural Internal Force Analysis, Traveling Wave Effect

1昆明市建设工程质量安全监督管理总站，云南 昆明

2昆明理工大学，建筑工程学院，云南 昆明

1. 工程概况

Figure 1. Layout of bridge facade

Figure 2. Bridge finite element model

2. 行波效应对弹塑性动力分析的影响

2.1. 行波效应对位移的影响

1) 同一位置不同波速下，波速越低相位差也就越大，行波效应会造成位移的增大或者减小，折线图具有一定的波动性，波速越低折线图的波动就会越大，当波速小于500 m/s时波动最大；

2) 同一位置不同波速下，波速越高相位差也就越小，行波效应对位移影响也就越小，波速越高位移越趋近于一致激励。

2.2. 行波效应对内力的影响

1) 1#桥墩左肢墩墩顶在100 m/s波速下相对于一致激励时内力MY减小达到24.9%；2#桥墩左肢墩墩顶在200 m/s波速下相对于一致激励时内力MY增大达到17.1%；

2) 同一位置不同波速下，波速越低相位差会越大，行波效应会导致其弯矩MY增大或者减小。大多数波速下是减小的，折线图具有一定的波动性，波速越低折线图的波动会越大。随着波速增大曲线的趋于平缓，行波效应下内力与一致激励下内力的最大差值基本上在250 m/s波速下出现的；

Table 1. Peak displacement along the bridge under traveling wave effect

Table 2. MY peak value of bending moment under traveling wave effect

Figure 3. Comparison of 1# bridge pier left pier pier top uniform excitation and traveling wave effect of peak displacement along bridge

Figure 4. Comparison of 2# bridge pier left pier pier top uniform excitation and traveling wave effect of peak displacement along bridge

Figure 5. Comparison of 3# bridge pier left pier pier top uniform excitation and traveling wave effect of peak displacement along bridge

Figure 6. Maximum MY comparison of 1# pier’s left pier pier top under uniform excitation and traveling wave effect

Figure 7. Maximum MY comparison of 2# pier’s left pier pier top under uniform excitation and traveling wave effect

Figure 8. Maximum MY comparison of 3# pier’s left pier pier top under uniform excitation and traveling wave effect

3) 同一位置不同波速下，波速越高相位差会越小。行波效应对内力弯矩MY的影响也越小，波速越高MY峰值越趋近于一致激励。当波速大于1500 m/s时，行波效应对内力影响趋于较小。

3. 结论

1) 在行波效应的影响下，当波速较低时，行波效应会导致特征截面的位移值相对于一致激励时产生一定的波动，尤其是在500 m/s的波速内波动最大，可见当在软土地基中时，低波速行波效应对弹塑性动力时程分析法的位移结果会产生较大影响，在类似场地条件及类似大跨度矮塔斜拉桥的抗震设计中应注意对行波效应的考虑。

2) 在行波效应的影响下，当波速较高，相位差较小时，随着波速的增大，位移结果值是不断趋近于一致激励的，当波速大于1000 m/s以上时，位移结果值几乎是单调增长并不断趋近于一致激励结果；可见在基岩地基中，高波速时行波效应对弹塑性动力时程分析法的位移结果影响较小。

3) 在行波效应的影响下，弹塑性动力时程分析的内力结果与位移结果变化规律类似。在500 m/s以内波速时，内力结果的波动较大，相对于一致激励时，增大或减小的最大值在20%以上。当大跨矮塔斜拉桥位于软土地基上时，行波效应的考虑是非常必要的。当波速大于1000 m/s以上时，内力结果值是不断趋近于一致激励结果。因此当大跨矮塔斜拉桥位于基岩地基中时，高波速行波效应对弹塑性动力时程分析的内力结果影响较小。

Seismic Analysis of Low Pylon Cable-Stayed Bridge Based on Traveling Wave Effect[J]. 土木工程, 2018, 07(05): 739-745. https://doi.org/10.12677/HJCE.2018.75088

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