本文選題：近場(chǎng)豎向地震 + V/H譜��； 參考：《南京理工大學(xué)》2014年博士論文

【摘要】：隨著地震監(jiān)測(cè)網(wǎng)的加密和監(jiān)測(cè)手段的更新,越來(lái)越多的近場(chǎng)地震的監(jiān)測(cè)數(shù)據(jù)表明,豎向地震加速度幅值往往超出了預(yù)期值。近年來(lái)坂神、集-集和汶川等近場(chǎng)地震造成的嚴(yán)重橋梁震害不能全部用傳統(tǒng)的水平地震震因解釋,如環(huán)形裂縫,支座斷裂和橋墩局部破壞等,而用豎向地震震因解釋被認(rèn)為更合理。高幅值的豎向地震動(dòng)被認(rèn)為可以?huà)伷鹬髁?分離橋梁與支座,導(dǎo)致橋梁再次落下時(shí)與支座產(chǎn)生重碰撞(pounding)。由此產(chǎn)生的橋梁動(dòng)力學(xué)響應(yīng)涉及變接觸約束拓?fù)錁?gòu)形、橋梁結(jié)構(gòu)內(nèi)部的碰撞波動(dòng)效應(yīng)、局部結(jié)構(gòu)破壞和非線(xiàn)性動(dòng)力效應(yīng)等復(fù)雜力學(xué)問(wèn)題,理論和數(shù)值研究困難大。由于直接到現(xiàn)場(chǎng)實(shí)地觀(guān)察幾無(wú)可能,目前有關(guān)豎向地震引發(fā)橋梁震害的解釋,僅是根據(jù)震后橋梁損壞狀態(tài)所作的字面上的判斷和猜測(cè),沒(méi)有理論依據(jù)和數(shù)值計(jì)算依據(jù),存在相當(dāng)?shù)臓?zhēng)議,并且也有一些其它不同的解釋。缺乏必要的可靠理論方法的分析結(jié)果,甚至尚缺乏橋梁豎向地震響應(yīng)的基礎(chǔ)性研究。與橋梁的水平地震響應(yīng)相比,豎向地震響應(yīng)的研究缺乏,缺乏對(duì)橋梁豎向地震的基本認(rèn)識(shí),甚至缺乏基本的理論研究方法。本文運(yùn)用瞬態(tài)波特征函數(shù)展開(kāi)法,建立了帶橡膠支座橋梁在近場(chǎng)豎向地震作用下碰撞響應(yīng)分析的理論方法,研究了橋梁豎向碰撞響應(yīng)的若干基本特征。本文的主要研究工作包括：(1)針對(duì)近場(chǎng)豎向地震動(dòng)引起的橋梁多次碰撞響應(yīng)問(wèn)題,建立了“梁-彈簧-桿”連續(xù)體模型,采用瞬態(tài)波特征函數(shù)展開(kāi)法,考慮主梁與支座碰撞接觸與分離狀態(tài)的切換,以及碰撞波在橋梁內(nèi)的傳播效應(yīng),建立了既可以分析橋梁碰撞瞬態(tài)響應(yīng),又可以完成全地震周期內(nèi)橋梁地震響應(yīng)分析的理論研究方法。(2)針對(duì)人工簡(jiǎn)諧豎向地震動(dòng)作用,研究了帶橡膠支座雙跨連續(xù)梁橋的地震響應(yīng)。運(yùn)用瞬態(tài)波特征函數(shù)展開(kāi)法,推導(dǎo)了橋梁多次碰撞響應(yīng)的理論解。數(shù)值研究了理論解對(duì)計(jì)算時(shí)間步長(zhǎng)和波模態(tài)截?cái)鄶?shù)的收斂性,計(jì)算了地震波和碰撞激發(fā)瞬態(tài)波在橋梁結(jié)構(gòu)內(nèi)的傳播,觀(guān)察了多次碰撞現(xiàn)象,研究了豎向地震激勵(lì)周期和幅值的影響,探討了碰撞響應(yīng)與豎向地震激勵(lì)的關(guān)系,以及碰撞響應(yīng)對(duì)橋梁結(jié)構(gòu)安全的影響。發(fā)現(xiàn)的橋梁若干異常損壞形式與橋梁豎向地震下的碰撞響應(yīng)存在密切的聯(lián)系。(3)針對(duì)人工簡(jiǎn)諧豎向地震動(dòng)作用,通過(guò)改變地震激勵(lì)周期、橋梁結(jié)構(gòu)固有周期和地震激勵(lì)幅值,大量計(jì)算了豎向碰撞次數(shù)和最大碰撞力,詳細(xì)研究了豎向地震激勵(lì)周期、豎向地震激勵(lì)幅值和橋梁結(jié)構(gòu)固有周期對(duì)豎向碰撞的影響。研究發(fā)現(xiàn)隨著豎向地震激勵(lì)周期的變化,橋梁間斷出現(xiàn)了3個(gè)豎向碰撞區(qū),3個(gè)豎向碰撞區(qū)分別處在橋梁的前3階豎向固有振動(dòng)周期附近,碰撞區(qū)的出現(xiàn)與豎向地震激勵(lì)幅值有關(guān)。另外,近場(chǎng)豎向地震激勵(lì),容易引發(fā)處在橋梁的第2階和第3階豎向固有振動(dòng)周期附近的豎向碰撞,與遠(yuǎn)場(chǎng)地震響應(yīng)明顯不同。(4)對(duì)比分析了“梁-彈簧-桿”連續(xù)體模型和“梁-桿”連續(xù)體模型,研究表明“梁-彈簧-桿”連續(xù)體模型更為合理。系統(tǒng)研究了橋梁結(jié)構(gòu)和材料參數(shù)橋梁豎向地震下的碰撞特性和響應(yīng)的影響,研究表明橋梁支座剛度、主梁跨度和抗彎剛度的影響明顯,橋墩高度和橋墩彈性模量的影響不大,但是,在高墩橋下出現(xiàn)了第4個(gè)碰撞區(qū)。因此,合理設(shè)計(jì)的橋梁結(jié)構(gòu)有可能降低豎向地震下橋梁碰撞的烈度和出現(xiàn)頻次,提高橋梁抵抗豎向地震的能力。(5)對(duì)實(shí)際近場(chǎng)豎向地震動(dòng)記錄的離散數(shù)據(jù)進(jìn)行快速傅里葉變換(FFT)分析,將其展開(kāi)成各頻率成份簡(jiǎn)諧波的疊加,考慮橋梁支座的作用,采用瞬態(tài)波特征函數(shù)法,推導(dǎo)了實(shí)際近場(chǎng)豎向地震動(dòng)作用下帶支座橋梁結(jié)構(gòu)多次碰撞響應(yīng)的理論解。并且,建立橋梁結(jié)構(gòu)三維彈性有限元模型,用于對(duì)比理論解和有限元方法計(jì)算的結(jié)果,驗(yàn)證理論方法的可靠性和精度。通過(guò)數(shù)值算例,計(jì)算了實(shí)際近場(chǎng)豎向地震動(dòng)作用下帶支座橋梁結(jié)構(gòu)碰撞響應(yīng),研究了實(shí)際近場(chǎng)豎向地震動(dòng)作用下多次豎向碰撞特性。研究表明本文建立的理論方法可以用來(lái)指導(dǎo)有限元模型的建立,判斷有限元數(shù)值結(jié)果的正確性。在實(shí)際近場(chǎng)豎向地震作用下,橋梁結(jié)構(gòu)可能發(fā)生豎向碰撞現(xiàn)象和多次豎向碰撞現(xiàn)象。豎向碰撞現(xiàn)象出現(xiàn)近場(chǎng)豎向地震的主要激勵(lì)周期與橋梁整體結(jié)構(gòu)的前2階固有振動(dòng)周期逼近時(shí),并且在橋梁第2階固有振動(dòng)周期附近的碰撞,其作用效果接近甚至超過(guò)在橋梁第1階固有振動(dòng)周期附近的碰撞。在強(qiáng)近場(chǎng)豎向地震動(dòng)激勵(lì)作用下,在橋梁彎矩會(huì)出現(xiàn)反轉(zhuǎn),橋墩會(huì)出現(xiàn)高幅值波動(dòng)的軸向壓應(yīng)力,甚至出現(xiàn)軸向拉應(yīng)力,這些現(xiàn)象與觀(guān)察到的橋梁結(jié)構(gòu)的異常破壞現(xiàn)象相吻合。在實(shí)際近場(chǎng)豎向地震動(dòng)激勵(lì)作用下的計(jì)算分析結(jié)果,驗(yàn)證了通過(guò)單個(gè)主簡(jiǎn)諧豎向地震波作用下得到的豎向碰撞特性。
[Abstract]:With the encryption of seismic monitoring network and the updating of monitoring methods, more and more monitoring data of near field earthquakes show that the amplitude of vertical seismic acceleration is often beyond the expected value. In recent years, the serious bridge damage caused by the near field earthquake of Sakamoto, set set and Wenchuan can not be explained entirely by the horizontal seismic seismic cause, such as ring cracks and branches. It is considered more reasonable to explain the partial fracture of the seat and the pier of the pier, and it is considered more reasonable to use the vertical seismic seismic explanation. The vertical ground motion of the high amplitude is considered to be able to throw up the main beam and separate the bridge and support, causing the bridge to have a heavy collision with the support (pounding) when the bridge falls down again. The collision wave effect, the local structural failure and the nonlinear dynamic effect in the structure are difficult. The theoretical and numerical research is difficult. The explanation of the bridge earthquake damage caused by the vertical earthquake is only the literal judgment and guessing based on the damage state of the bridge after the earthquake. There is no theoretical basis and numerical basis, there are considerable disputes, and there are some other different interpretations. Lack of the necessary analytical results of reliable theoretical methods, and even the lack of basic research on bridge vertical seismic response. Compared with the horizontal seismic response of the bridge, the study of vertical seismic response is lack and the bridge erection is lacking. The basic understanding of the earthquake and even the lack of basic theoretical research methods. This paper uses the transient wave characteristic function expansion method to establish the theoretical method of the impact response analysis of the bridge with rubber bearing under the near field vertical earthquake, and studies some basic characteristics of the bridge vertical impact response. The main research work of this paper includes: (1) needle The "beam spring rod" continuum model is established for the multiple impact response of the bridge caused by the near field vertical ground motion. The transient wave characteristic function expansion method is adopted to consider the switch between the collision contact and separation state of the main beam and the bearing and the propagation effect of the collision wave in the bridge. The theoretical research method of seismic response analysis of bridge in the whole earthquake cycle can be completed. (2) in view of the artificial simple harmonic vertical ground motion, the seismic response of the double span continuous beam bridge with rubber bearing is studied. The theoretical solution of the multiple impact response of the bridge is derived by using the transient wave characteristic function expansion method. The numerical study on the calculation time of the theoretical solution is studied. The convergence of step length and wave mode truncation number, the propagation of seismic wave and collision excited transient wave in bridge structure is calculated, multiple collisions are observed, the influence of the period and amplitude of the vertical earthquake excitation is studied. The relationship between the impact response and the vertical earthquake excitation is discussed, and the impact of the collision response on the safety of the bridge structure is found. There is a close relationship between the abnormal damage forms of the bridge and the impact response of the bridge under the vertical earthquake. (3) in view of the vertical earthquake action of the artificial simple harmonic, the number of vertical collisions and the maximum impact force are calculated by changing the earthquake excitation period, the inherent period of the bridge structure and the amplitude of the earthquake excitation, and the vertical seismic excitation is studied in detail. The effect of periodic, vertical earthquake excitation amplitude and the inherent cycle of the bridge structure on the vertical collision is found. It is found that with the change of the vertical earthquake excitation period, 3 vertical collision zones are discontinuous, and the 3 vertical collision regions are located near the first 3 vertical natural vibration cycles of the bridge, and the occurrence of the collision area and the amplitude of the vertical earthquake excitation are found. In addition, the vertical seismic excitation in the near field is easy to cause the vertical collision near the second and third order vertical natural vibration cycles of the bridge, which is obviously different from the far field seismic response. (4) the "beam spring rod" continuum model and the "beam rod" continuum model are compared and analyzed, and the study shows that the "beam spring rod" continuum model is more important. The impact of bridge structure and material parameter bridge on the impact characteristics and response of bridge under vertical earthquake is studied systematically. The study shows that the influence of bridge support stiffness, girder span and flexural rigidity is obvious, the influence of pier height and pier modulus of elasticity is not significant, but fourth collision zones appear under the high pier bridge. Therefore, reasonable design The bridge structure may reduce the intensity and frequency of the bridge collision in the vertical earthquake, and improve the ability of the bridge to resist the vertical earthquake. (5) the fast Fourier transform (FFT) analysis of the discrete data of the actual near field vertical ground motion records is carried out to form the superposition of the harmonic waves of each frequency, and the effect of the bridge support is taken into consideration. The transient wave characteristic function method is used to derive the theoretical solution of multiple impact responses of the bridge structure with a supporting bridge under the action of the actual near field vertical ground motion. And a three-dimensional elastic finite element model of the bridge structure is established to verify the reliability and accuracy of the theoretical square method by comparing the results of the theoretical solution and the finite element method. Under the actual near field vertical ground motion, the impact response of the bearing bridge structure is studied. The multiple vertical impact characteristics of the actual near field vertical ground motion are studied. The study shows that the theoretical method established in this paper can be used to guide the establishment of the finite element model and judge the correctness of the finite element numerical results. Under the actual near field vertical earthquake, The vertical impact and multiple vertical collisions may occur in the bridge structure. The main excitation period of the vertical impact of the vertical impact and the first 2 natural vibration cycles of the bridge overall structure are approaching, and the impact near the second order inherent vibration period of the bridge is close to even more than the first order of the bridge. There will be a reversal in the bending moment of the bridge under the excitation of the strong near field vertical ground motion. The axial compressive stress of the bridge pier will appear with high amplitude fluctuation, and even the axial tensile stress appears. These phenomena coincide with the abnormal failure phenomenon of the observed bridge structure. The excitation effect of the vertical ground motion in the actual near field. The results of calculation and analysis verify the vertical collision characteristics under the action of a single principal harmonic vertical seismic wave.
【學(xué)位授予單位】：南京理工大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：U442.55

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本文編號(hào)：2081314