發(fā)布時(shí)間：2018-12-10 16:30

【摘要】：橋梁的安全問(wèn)題一直受業(yè)內(nèi)人士的關(guān)注,橋梁使用壽命的設(shè)計(jì)基準(zhǔn)期一般為100年,隨著我國(guó)社會(huì)經(jīng)濟(jì)的發(fā)展,我國(guó)公路運(yùn)輸?shù)慕煌髁亢蛙?chē)輛荷載都呈增長(zhǎng)趨勢(shì),特別是在我國(guó)自然資源豐富的中西部地區(qū),交通荷載具有大流量、高軸載的特點(diǎn),公路橋梁在長(zhǎng)期高軸載作用下,會(huì)加劇橋梁的損壞,嚴(yán)重影響橋梁的使用壽命,車(chē)輛荷載對(duì)橋梁結(jié)構(gòu)的疲勞損傷不容忽視。我國(guó)《公路橋涵設(shè)計(jì)通用規(guī)范》(JTGD60-2004)中規(guī)定了橋梁的車(chē)輛荷載分為公路-Ⅰ級(jí)和公路-Ⅱ級(jí)兩個(gè)等級(jí),汽車(chē)荷載由車(chē)道荷載和車(chē)輛荷載組成,尚缺乏用于公路橋梁疲勞性能評(píng)估的疲勞荷載譜,且針對(duì)公路橋梁疲勞設(shè)計(jì)的車(chē)輛荷載目前的研究還不夠深入。本文針對(duì)重載公路貨運(yùn)通道的車(chē)輛荷載進(jìn)行研究,并選取典型橋梁進(jìn)行疲勞壽命預(yù)測(cè)。主要工作內(nèi)容如下：(1)選取重載公路貨運(yùn)通道典型路段對(duì)車(chē)輛類(lèi)型、車(chē)間距、車(chē)重和車(chē)輛橫向分布情況進(jìn)行了現(xiàn)場(chǎng)調(diào)查與統(tǒng)計(jì)分析,擬合出車(chē)間距和各車(chē)型車(chē)重分布的概率密度函數(shù),根據(jù)由Miner準(zhǔn)則推導(dǎo)出的等效軸重和等效軸距計(jì)算公式,將具有相同軸數(shù)的不同車(chē)輛簡(jiǎn)化為一種典型車(chē)輛模型,最終得到適用于重載公路疲勞計(jì)算的疲勞車(chē)輛荷載頻值譜,通過(guò)計(jì)算各車(chē)型對(duì)橋梁的損傷度,選擇貢獻(xiàn)最大的車(chē)型作為標(biāo)準(zhǔn)疲勞車(chē)的基本形式,并對(duì)不同跨徑的簡(jiǎn)支梁橋計(jì)算其軸重修正系數(shù),建立基于20m簡(jiǎn)支梁的標(biāo)準(zhǔn)疲勞車(chē)輛模型。(2)根據(jù)實(shí)際調(diào)查的交通數(shù)據(jù),運(yùn)用Matlab編寫(xiě)程序,模擬車(chē)輛荷載的隨機(jī)過(guò)程,選取13m簡(jiǎn)支板梁和20m簡(jiǎn)支T梁,對(duì)其進(jìn)行跨中彎矩影響線(xiàn)加載,計(jì)算在模擬的隨機(jī)車(chē)輛荷載作用下的彎矩時(shí)間歷程,并運(yùn)用雨流計(jì)數(shù)法計(jì)算彎矩幅和統(tǒng)計(jì)彎矩幅的分布規(guī)律,擬合得到兩種梁型的彎矩幅分布概率密度函數(shù)。(3)利用ANSYS對(duì)兩種簡(jiǎn)支梁進(jìn)行加載破壞全過(guò)程分析,確定其開(kāi)裂荷載、屈服荷載和破壞荷載。為了確定所選梁型在調(diào)查的荷載作用下的使用壽命,引入基于應(yīng)力的疲勞壽命預(yù)測(cè)方法對(duì)其疲勞壽命預(yù)測(cè)分析;建立各材料的疲勞本構(gòu)關(guān)系,應(yīng)用ANSYS有限元軟件計(jì)算簡(jiǎn)支梁經(jīng)過(guò)不同次數(shù)疲勞荷載作用后的剩余承載力,結(jié)果表明,隨著疲勞荷載作用次數(shù)的增加,簡(jiǎn)支梁的疲勞剩余承載力一直呈下降趨勢(shì)。
[Abstract]:The safety problem of bridges has been concerned by the industry all the time. The design reference period of bridge service life is generally 100 years. With the development of our country's social economy, the traffic flow and vehicle load of highway transportation in our country are increasing. Especially in the central and western regions rich in natural resources, traffic load has the characteristics of large discharge and high axial load. Under the action of long-term high axial load, highway bridge will aggravate the damage of the bridge and seriously affect the service life of the bridge. The fatigue damage of bridge structure caused by vehicle load can not be ignored. The General Code for Design of Highway Bridges and culverts (JTGD60-2004) stipulates that the vehicle loads of bridges are divided into two classes: highway class 鈪，

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