【摘要】：隨著高速公路的發(fā)展，預(yù)應(yīng)力混凝土連續(xù)梁橋以其橋墩少、受力合理等獨(dú)特優(yōu)勢而被廣泛使用。預(yù)應(yīng)力混凝土連續(xù)梁橋主梁連接部負(fù)彎矩區(qū)壓應(yīng)力的儲(chǔ)備，克服了自重大的難題，使其極限承載能力得到普遍認(rèn)可。但這并不代表它具有良好的疲勞耐久性，尤其在密集的車流量長期作用下，其疲勞強(qiáng)度能否滿足使用要求仍然存在疑慮。因此，本文重點(diǎn)以預(yù)應(yīng)力混凝土連續(xù)梁橋——重慶石柱橋?yàn)樵停糜邢拊浖M分析預(yù)應(yīng)力混凝土連續(xù)梁橋在車輛荷載作用下的疲勞性能，主要研究內(nèi)容及結(jié)論如下： ①建立石柱橋有限元實(shí)體模型，對施加預(yù)應(yīng)力后的連續(xù)梁橋進(jìn)行模態(tài)分析，根據(jù)固有振型確定橋梁剛度薄弱部位、應(yīng)力集中部位即為疲勞破壞危險(xiǎn)部位。 ②運(yùn)用MATLAB軟件編程以實(shí)現(xiàn)服從對數(shù)正態(tài)分布的隨機(jī)車輛荷載譜模擬，將該荷載譜隨機(jī)作用于橋面行車道上，對預(yù)應(yīng)力混凝土連續(xù)梁橋進(jìn)行瞬態(tài)（Transient）動(dòng)力分析，計(jì)算車輛荷載對橋梁上部結(jié)構(gòu)的動(dòng)力響應(yīng)。 ③基于混凝土及預(yù)應(yīng)力鋼絞線的疲勞S—N曲線分析理論，將求解的結(jié)果通過雨流計(jì)數(shù)法處理，計(jì)算出該橋梁危險(xiǎn)截面材料的等效常幅應(yīng)力水平、等效常應(yīng)力幅和循環(huán)次數(shù)等相關(guān)參數(shù)；根據(jù)線性疲勞累積損傷理論，計(jì)算危險(xiǎn)部位材料的疲勞壽命和疲勞損傷度，分析得到：在車輛荷載譜作用下，，預(yù)應(yīng)力混凝土連續(xù)梁橋的疲勞壽命取決于混凝土材料的疲勞壽命；車輛荷載引起高應(yīng)力狀態(tài)下預(yù)應(yīng)力筋的疲勞損傷度比混凝土小；跨中部位預(yù)應(yīng)力筋的動(dòng)力響應(yīng)比支座部位大。 ④基于前人實(shí)際調(diào)查統(tǒng)計(jì)的車輛荷載譜，采用與隨機(jī)車輛荷載譜相同的車流量和加載方式將其作用于橋面行車道上，計(jì)算預(yù)應(yīng)力混凝土連續(xù)梁橋危險(xiǎn)部位材料的疲勞壽命和疲勞損傷度；比較兩種荷載譜作用下橋梁疲勞參數(shù)的計(jì)算結(jié)果得到：兩種荷載譜引起橋梁的動(dòng)力響應(yīng)特性較為接近，甚至服從正態(tài)分布的隨機(jī)車輛荷載譜比按統(tǒng)計(jì)調(diào)查比例分布的車輛荷載譜模擬加載結(jié)果更保守，可見用于驗(yàn)算分析預(yù)應(yīng)力混凝土連續(xù)橋梁的疲勞特性是可行的。
[Abstract]:With the development of expressway, prestressed concrete continuous beam bridge is widely used because of its unique advantages such as less piers and reasonable force. The storage of compressive stress in the negative moment region of the main girder connection of prestressed concrete continuous beam bridge overcomes the self-important problem and makes its ultimate bearing capacity generally accepted. However, this does not mean that it has good fatigue durability, especially under the effect of dense traffic flow for a long time, whether its fatigue strength can meet the requirements of use is still doubtful. Therefore, this paper focuses on the prestressed concrete continuous beam bridge-Chongqing stone column bridge as the prototype, using finite element software to simulate the fatigue performance of prestressed concrete continuous beam bridge under vehicle load. The main research contents and conclusions are as follows: 1 the finite element solid model of stone column bridge is established, the modal analysis of prestressed continuous beam bridge is carried out, and the weak position of bridge stiffness is determined according to the inherent mode of vibration. Stress concentration is the dangerous part of fatigue failure. (2) the MATLAB software is used to realize the simulation of random vehicle load spectrum with logarithmic normal distribution. The load spectrum is applied randomly on the carriageway of the bridge deck, and the transient (Transient) dynamic analysis of prestressed concrete continuous beam bridge is carried out. The dynamic response of the vehicle load to the superstructure of the bridge is calculated. Based on the theory of fatigue S-N curve analysis of concrete and prestressed steel strands, the equivalent constant amplitude stress level of the dangerous section material of the bridge is calculated by the method of rain flow counting. Equivalent constant stress amplitude and cycle number and other related parameters; According to the theory of linear fatigue cumulative damage, the fatigue life and the degree of fatigue damage of materials in dangerous parts are calculated. It is concluded that under the action of vehicle load spectrum, the fatigue life of prestressed concrete continuous beam bridge depends on the fatigue life of concrete material; The fatigue damage of prestressed tendons caused by vehicle load is smaller than that of concrete, and the dynamic response of prestressed tendons in mid-span is larger than that in support. (4) based on the vehicle load spectrum investigated by predecessors, the vehicle flow and loading mode which is the same as the random vehicle load spectrum is applied to the bridge deck carriageway. The fatigue life and fatigue damage degree of the material in the dangerous part of prestressed concrete continuous beam bridge are calculated. Comparing the calculation results of the fatigue parameters of the bridges under two load spectra, it is concluded that the dynamic response characteristics of the bridges caused by the two kinds of load spectra are close. Even the random vehicle load spectrum with normal distribution is more conservative than the simulation result of vehicle load spectrum which is distributed in proportion to the statistical investigation. It can be seen that it is feasible to analyze the fatigue characteristics of prestressed concrete continuous bridge by checking calculation.
【學(xué)位授予單位】：重慶交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：U448.35;U441.4

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