【摘要】：板式橡膠支座是我國中小跨徑公路梁橋中廣泛采用的支座類型,為便于施工和安裝,板式橡膠支座通常直接擱置在橋墩墩頂蓋梁或墊石上,支座與梁底和墩頂沒有連接措施。汶川地震中采用板式橡膠支座的中小跨徑公路梁橋震害以主梁移位、支座和擋塊破壞為主,橋墩震害率較低。為研究中小跨徑公路梁橋的震害機(jī)理和合理的抗震設(shè)計(jì)方法,本文針對(duì)采用板式橡膠支座的中小跨徑梁橋結(jié)構(gòu)體系,對(duì)支座在地震作用下優(yōu)先發(fā)生損傷和“多道設(shè)防、分級(jí)耗能”的抗震性能設(shè)計(jì)方法開展了系統(tǒng)研究,主要研究內(nèi)容和成果如下：1.揭示了橋梁震害與橋梁結(jié)構(gòu)體系的分布規(guī)律,發(fā)現(xiàn)了汶川地震中橋梁震害率較低的原因。地震作用下,采用板式橡膠支座的橋梁結(jié)構(gòu)體系傳力路徑中斷,減小了傳遞到下部結(jié)構(gòu)的地震力,支座起到了隔震耗能的作用。在此基礎(chǔ)上,提出了考慮板式橡膠支座摩擦滑移的中小跨徑橋梁抗震設(shè)計(jì)方法。2.首次進(jìn)行了不同錨固條件下板式橡膠支座的抗震性能試驗(yàn)研究。試驗(yàn)結(jié)果表明,當(dāng)板式橡膠支座上下面均錨固時(shí),破壞形式為橡膠層撕裂,極限剪切變形可達(dá)到300%~400%,加載位移較大時(shí),支座發(fā)生硬化現(xiàn)象；當(dāng)板式橡膠支座錨固一面時(shí),支座受力可分為兩階段：滑動(dòng)前和滑動(dòng)后,其滑移特性與支座所受的豎向荷載和支座規(guī)格有關(guān),并且考慮摩擦滑移的板式橡膠支座與鉛芯橡膠支座的耗能效果接近。在此基礎(chǔ)上,提出了考慮摩擦滑移的板式橡膠支座的等效剛度和等效阻尼比。3.建立了考慮摩擦滑移的板式橡膠支座-橋墩串聯(lián)體系的剛度比控制方程,該方程綜合考慮了軸壓比、支座厚度、支座變形、橋墩及支座非線性等的影響,得出了地震作用下支座先于橋墩發(fā)生損傷的剛度比限值,并根據(jù)限位裝置參數(shù)對(duì)板式橡膠支座橋梁位移控制進(jìn)行了研究,確定了限位裝置合理間隙的取值范圍。4.基于能量分析方法,對(duì)比分析了考慮摩擦滑移的板式橡膠支座、鉛芯橡膠支座橋梁中橋墩和支座的滯回耗能,驗(yàn)證了考慮摩擦滑移的板式橡膠支座具有良好的抗震性能,并分析了影響橋梁抗震性能的因素;通過IDA增量時(shí)程分析研究了地震作用下不同橋梁體系中各構(gòu)件的抗震性能,提出了板式橡膠支座橋梁順橋向和橫橋向合理的損傷模式。5.采用等效線性化概念,建立了考慮摩擦滑移的板式橡膠支座-橋墩雙自由度模型的位移設(shè)計(jì)方法及具有多道防線的橋梁抗震設(shè)計(jì)方法,提出了不同水準(zhǔn)地震作用下橋梁各構(gòu)件的性能目標(biāo)和性能要求,并通過一算例,驗(yàn)證了不同水準(zhǔn)下多道抗震防線的抗震設(shè)計(jì)方法的可行性和合理性。
[Abstract]:The plate rubber bearing is widely used in the middle and small span highway girder bridge in our country. In order to facilitate the construction and installation, the plate rubber support is usually placed directly on the top beam or cushion stone of the pier, and there is no connection measure between the support and the beam bottom and the pier top. In Wenchuan earthquake, the earthquake damage of small and medium span highway girder bridge with plate rubber bearing is mainly caused by the displacement of main beam, the damage of support and block, and the low damage rate of bridge pier. In order to study the earthquake damage mechanism and reasonable seismic design method of middle and small span highway beam bridge, this paper aims at the structure system of medium and small span beam bridge with plate rubber bearing, and gives priority to damage and "multi-channel fortification" to the support under earthquake action. The seismic performance design method of graded energy dissipation is studied systematically. The main contents and results are as follows: 1. The distribution law of bridge earthquake damage and bridge structure system is revealed, and the reason of low bridge damage rate in Wenchuan earthquake is found. Under seismic action, the transmission path of bridge system with plate rubber bearing is interrupted, the seismic force transferred to the substructure is reduced, and the bearing plays the role of isolation and energy dissipation. On this basis, the aseismic design method of medium and small span bridge considering friction and slip of plate rubber bearing is put forward. The seismic behavior of plate rubber bearing under different anchoring conditions was studied for the first time. The test results show that when the upper and lower parts of the plate rubber bearing are anchored, the failure form is rubber layer tear, the ultimate shear deformation can reach 300 ~ 400 and the bearing hardening occurs when the loading displacement is large, and when the plate rubber support is anchored on one side, The bearing force can be divided into two stages: before and after sliding, the slip characteristics are related to the vertical load and the bearing size of the bearing, and the energy dissipation effect of the plate rubber bearing with friction slip is close to that of the lead rubber bearing. On this basis, the equivalent stiffness and damping ratio of plate rubber bearing considering friction slip are proposed. The governing equation of stiffness ratio of plate rubber bearing-pier series system considering friction slip is established. The equation considers the influence of axial compression ratio, bearing thickness, bearing deformation, bridge pier and support nonlinearity, etc. The limit value of stiffness ratio of bearing before bridge pier under earthquake action is obtained, and the displacement control of plate rubber bearing bridge is studied according to the parameters of limit device, and the value range of reasonable clearance of limit device is determined. Based on the energy analysis method, the hysteretic energy consumption of the plate rubber bearing with friction slip and the bridge pier and bearing in the lead rubber bearing bridge are compared and analyzed. The results show that the plate rubber bearing with friction slip has good seismic performance. The factors affecting the seismic performance of the bridge are analyzed, and the seismic behavior of each member in different bridge systems under earthquake is studied by IDA incremental time-history analysis, and the reasonable damage mode of the slab rubber bearing bridge is put forward. Based on the concept of equivalent linearization, the displacement design method of plate rubber bearing-pier model with double degrees of freedom and the seismic design method of bridges with multiple lines of defense are established. The performance objectives and performance requirements of each component of the bridge under the action of different leveling earthquakes are put forward, and the feasibility and rationality of the seismic design method of multi-channel anti-seismic lines at different levels are verified by an example.
【學(xué)位授予單位】：東南大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：U442.55
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本文編號(hào)：2193414