曲線連續梁橋在車輛制動作用下的動力響應

陳水生 羅浩 桂水榮

摘 要： 以某一匝道公路曲線連續箱梁橋為例，分析了該類橋梁的空間車橋耦合振動問題。用ANSYS軟件模擬梁橋，選用典型的三軸空間車輛模型，采用模態綜合法編制公路曲線車橋耦合振動響應MATLAB程序，獲得了車輛制動作用下曲線連續梁橋的動力響應及沖擊系數，研究了初速度、制動位置、制動力上升時間、橋面平整度等參數對沖擊系數的影響。結果表明：車輛制動時，主梁最大撓度、撓度和內力沖擊系數沒有隨初速度的增大而單調遞增或遞減，但均明顯大于車輛以相同初速度勻速行駛時的結果，且可能超過規范值。在橋前半跨內制動時，撓度和跨中剪力沖擊系數大于在后半跨度內制動情況，同時，當車輛制動位置大于半跨且越靠近支點時，車輛制動時撓度和內力沖擊系數越接近勻速時的結果。隨著曲率半徑的增大，橋梁的撓度、彎矩和扭矩沖擊系數逐漸減小，而剪力沖擊系數逐漸增大;彎橋的撓度、彎矩和扭矩沖擊系數大于直線橋結果，緊急制動易于加劇橋梁的振動。

關鍵詞： 曲線連續梁橋;車輛制動;動力響應;沖擊系數;Runge-Kuntta算法

中圖分類號：U443.3? ? 文獻標志碼：A? ?文章編號：2096-6717（2020）02-0095-12

Dynamic response of curved continuous girder bridge under vehicle braking

Chen Shuisheng， Luo Hao， Gui Shuirong

（School of Civil Engineer and Architecture， East China Jiaotong University， Nanchang 330013， P.R.China）

Abstract： The coupling vibration of space vehicle-bridge of this kind of bridge was analyzed basing on a curved continuous box girder bridge on an ramp.The ANSYS software was used to simulate the beam bridge， and the typical three-axis space vehicle model was selected.The dynamic response and impact of the curved continuous box girder bridge under the braking effect of the vehicle were obtained by the MATLAB program of the highway curve using the modal comprehensive method.And the influence of initial speed， braking position， braking rising time and bridge deck smoothness on dynamic impact coefficient was studied.The results showed that the maximum deflection， deflection and internal force impact coefficient of the main girder do not increase or decrease monotonously with the increase of initial speed， but they are obviously larger than the results when the vehicle runs at the same initial speed and may exceed the standard value.The impact coefficient of deflection and mid-span shear force in front half-span braking is greater than that in the back half-span braking.At the same time， when the braking position of the vehicle is greater than half-span and closer to the fulcrum， the impact coefficient of deflection and internal force is closer to the result of uniform speed braking.With the increase of curvature radius， the impact coefficient of deflection ， bending moment and torsion of bridge decreases gradually， while the impact coefficient of shear force increases gradually.In addition， the impact coefficients of deflection， bending moment and torsion curved bridges are larger than those of straight bridges and emergency braking tends to aggravate bridge vibration.

Keywords： curved continuous beam bridge; vehicle braking; dynamic response; impact coefficient; Runge-Kunta algorithm

近年來，隨著公路建設、城市基礎設施和交通系統的迅速發展，越來越多曲線橋應用于高速公路的跨河聯通、大型城市立交匝道和橋梁橋頭引道中，因此，車輛作用下曲線梁橋振動問題值得關注。

目前，車橋耦合振動問題的研究大多數假設車輛在橋上勻速行駛，而在實際情況中，由于路線線形的變化等因素，車輛一般都是變速行駛的。……