本文選題：鋼管混凝土拱橋　切入點(diǎn)：吊桿損傷　出處：《華北水利水電大學(xué)》2017年碩士論文

【摘要】：鋼管混凝土拱橋以其獨(dú)特的力學(xué)性能,優(yōu)越的施工工藝在橋梁建設(shè)領(lǐng)域得到越來越多的青睞,隨著結(jié)構(gòu)的創(chuàng)新和跨徑的增大,還有各種偶然因素的出現(xiàn),鋼管混凝土拱橋等一類橋梁工程建設(shè)正面臨著巨大風(fēng)險,必須引起高度的重視,否則極易引起坍塌事故,給人們交通出行帶來不便�；贏NSYS建立一單跨30米的混凝土梁,研究了其材料、幾何參數(shù)、邊界條件、物理參數(shù)等對模態(tài)頻率的影響。結(jié)果顯示材料特性、幾何尺寸、邊界條件對模態(tài)頻率影響比較明顯,因此在利用模態(tài)頻率進(jìn)行損傷判斷時應(yīng)特別注意這幾個參數(shù)變化。以下承式拱橋習(xí)營東南跨渠生產(chǎn)橋?yàn)槔?利用有限元分析軟件ANSYS建立三維有限元模型,分析了習(xí)營東南跨渠生產(chǎn)橋在不同溫度和不同預(yù)應(yīng)力時,拱橋的動力特性。在-35℃~35℃的環(huán)境變溫時,拱橋的振型變化不明顯。當(dāng)環(huán)境溫度升高時,振動頻率隨溫度的升高而增大,隨溫度的降低而減小,但變化幅度較小。以習(xí)營東南跨渠生產(chǎn)橋?yàn)閷?shí)例展開對縱梁施加不同大小預(yù)應(yīng)力的情況下,對橋梁動力特征的影響,發(fā)現(xiàn)隨著預(yù)應(yīng)力增加振動頻率會增大,說明預(yù)應(yīng)力會改變拱橋的性能,進(jìn)而影響振動特征,但與溫度相比影響更小。并分析了吊桿損傷時拱橋力學(xué)性質(zhì)和位移情況,得出吊桿損傷程度一般大于吊桿張力的變化率,且吊桿損傷會引起相鄰幾根吊桿張力變大,單側(cè)吊桿損傷對拱橋?qū)?cè)吊桿的力學(xué)性能影響較小,可以不計(jì)。通過對不同工況下拱橋振動特征的分析,最后發(fā)現(xiàn)橋梁橫向振動、豎向振動和扭轉(zhuǎn)振動陣型依次出現(xiàn),因此得出拱橋的豎向和扭轉(zhuǎn)剛度明顯大于橫向剛度。對下承式鋼管拱橋結(jié)構(gòu)體系中的重要構(gòu)件進(jìn)行可靠度分析,結(jié)果顯示吊桿可靠度最高,因此設(shè)計(jì)時應(yīng)加強(qiáng)薄弱部位的強(qiáng)度。但是近幾年隨著下承式鋼管拱橋的發(fā)展,大多數(shù)事故都是因?yàn)榈鯒U損傷所引起的,因而進(jìn)一步開展對吊桿的安全評估研究是必要的。在實(shí)際工程實(shí)踐當(dāng)中應(yīng)采取一定措施加強(qiáng)安全監(jiān)測,以保證橋梁安全運(yùn)營。在以上分析的基礎(chǔ)上給出了一套下承式鋼管混凝土拱橋的安全預(yù)警方案,為現(xiàn)代鋼管拱橋技術(shù)的改進(jìn)及同類型拱橋安全監(jiān)測提供參考。
[Abstract]:Concrete-filled steel tubular arch bridge is more and more popular in the field of bridge construction with its unique mechanical properties and superior construction technology. With the innovation of structure and the increase of span, there are also a variety of accidental factors. The construction of concrete filled steel tube arch bridge and other bridge projects is facing great risks, which must be attached great importance to, otherwise, it is easy to cause collapse accident and bring inconvenience to people's transportation. Based on ANSYS, a concrete beam with a single span of 30 meters is established. The effects of materials, geometric parameters, boundary conditions and physical parameters on modal frequencies are studied. The results show that the effects of material properties, geometric dimensions and boundary conditions on modal frequencies are obvious. Therefore, special attention should be paid to the variation of these parameters when using modal frequency to judge damage. Taking the through arch bridge as an example, the three-dimensional finite element model is established by using the finite element analysis software ANSYS. The dynamic characteristics of the arch bridge under different temperature and different prestress are analyzed. When the ambient temperature changes from -35 鈩，

本文編號：1653675