公路路桥过渡段刚性楔形搭板设计参数优化
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摘要
桥头搭板能够有效抑制桥头跳车,但普通搭板易引起二次跳车等现象对行车不利,而刚性楔形搭板则可改善该问题。以车体垂向加速度均方根、搭板两端错台高度作为控制指标,建立了7自由度车辆模型和过渡段三维动力学模型,分析了桥头搭板的不同参数组合下车辆和过渡段的动力特性,对楔形搭板的最大厚度、弹性模量、上表面坡度和长度等参数进行了优化设计。结果表明,当搭板最大厚度为30cm、弹性模量为2.8×10~4 MPa、上表面坡度为2%、长度不小于7m时,远离桥台一端的错台高度满足轻微错台标准;当搭板最大厚度为30cm、弹性模量为2.8×10~4 MPa、长度为8m、搭板上表面坡度不小于1%时,满足舒适性要求;搭板的弹性模量对错台高度的影响不显著。建议搭板材质选取C35,长度、最大厚度分别不小于7m和30cm,上表面坡度不小于1%,以满足人体舒适性和错台高度的要求。
Approach slab can restrain the car-bounce at bridge-ends,but the normal slab always cause a second jump,while the wedged-shaped rigid slab can improve the problem.In the paper,with the root mean square of car body vertical acceleration and the heights of staggered platform on both ends as control index,the three-dimensional model of transitional section and seven DOFs vehicle model are built,the dynamic characteristics of the vehicle and the transition section are analyzed under different parameter combinations,the maximum thickness,elastic modulus,slope and length of the upper surface of the wedge are optimized.The results show that when the maximum thickness of the slabs is 30 cm,the elastic modulus is 2.8×10~4 MPa,the slope of the upper surface is 20‰,and the length is not less than 7 m,staggered platform altitude that far from the end of the bridge abutment meets the criteria of slight platform error.When the maximum thickness of the slabs is 30 cm,the elastic modulus is 2.8×10~4 MPa and the length is 8 m,when the slope of the surfaces on the slabs is no less than 10‰,the requirements for drive comfort are satisfied.The elastic modulus of the lap plate has no significant influence on staggered platform altitude.It is recommended to select C35 for slabs,the length and maximum thickness should be not less than 7 mand 30 cm respectively,and the slope of the upper surface should be not less than 10‰,so as to meet the requirements of drive comfort and staggered platform altitude.
Approach slab can restrain the car-bounce at bridge-ends,but the normal slab always cause a second jump,while the wedged-shaped rigid slab can improve the problem.In the paper,with the root mean square of car body vertical acceleration and the heights of staggered platform on both ends as control index,the three-dimensional model of transitional section and seven DOFs vehicle model are built,the dynamic characteristics of the vehicle and the transition section are analyzed under different parameter combinations,the maximum thickness,elastic modulus,slope and length of the upper surface of the wedge are optimized.The results show that when the maximum thickness of the slabs is 30 cm,the elastic modulus is 2.8×10~4 MPa,the slope of the upper surface is 20‰,and the length is not less than 7 m,staggered platform altitude that far from the end of the bridge abutment meets the criteria of slight platform error.When the maximum thickness of the slabs is 30 cm,the elastic modulus is 2.8×10~4 MPa and the length is 8 m,when the slope of the surfaces on the slabs is no less than 10‰,the requirements for drive comfort are satisfied.The elastic modulus of the lap plate has no significant influence on staggered platform altitude.It is recommended to select C35 for slabs,the length and maximum thickness should be not less than 7 mand 30 cm respectively,and the slope of the upper surface should be not less than 10‰,so as to meet the requirements of drive comfort and staggered platform altitude.
引文
[1]董鹏.高速公路桥头过渡段沉降差异分析及处理方法[J].铁道建筑,2008,(4):53-55.
[2]陈景星,冯忠居,郑木莲,等.基于安全性的路桥过渡段差异沉降控制标准[J].公路交通科技,2013,30(2):26-31.
[3]陈敦昌.以车辆运行平稳性为控制指标的公路桥头搭板参数优化研究[D].北京:北京交通大学,2015.
[4]H K W Wong I,J C Small.Effect of orientation of approach slabs on Pavement deformation[M].Journal of TransPortationEngineering,1994:590-602.
[5]Shi X M,Cai C S.Finite element analysis of concrete approach slab on soil embankment[J].Geotechnical Engineering for Transportation Projects,2004,126:393-402.
[6]Cai Chunsheng,Shi Xiaomin.Structural performance of bridge approach slabs under given embankment settlement[J].Journal of Bride Engineering,2005,10(4):482-489.
[7]J L Robison,R Luna.Deformation Analysis of Modeling of Missouri Bridge Approach Embankments[J].GeoTrans,2004:2020-2027.
[8]ISO 2631-1:1997Mechanical Vibration and Shock-Evaluation of Human Exposure to Whole-body Vibration[S].
[9]GB/T 13441.1-2007机械振动与冲击人体暴露于全身振动的评价第1部分一般要求[S].
[10]JTG H20-2007公路技术状况评定标准[S].
[11]Long J,Olson S,Stark T,et al.Differential Movement at Embankment-Bridge Structure Interface in Illinois[J].Transportation Research Record Journal of the Transportation Research Board,1998,1633(1):53-60.
[12]Shi X M,Cai C S.Simulation of dynamic effects of vehicles on pavement using a 3Dinteraction model[J].Journal of Transportation Engineering,2009,135(10):736-744.
[2]陈景星,冯忠居,郑木莲,等.基于安全性的路桥过渡段差异沉降控制标准[J].公路交通科技,2013,30(2):26-31.
[3]陈敦昌.以车辆运行平稳性为控制指标的公路桥头搭板参数优化研究[D].北京:北京交通大学,2015.
[4]H K W Wong I,J C Small.Effect of orientation of approach slabs on Pavement deformation[M].Journal of TransPortationEngineering,1994:590-602.
[5]Shi X M,Cai C S.Finite element analysis of concrete approach slab on soil embankment[J].Geotechnical Engineering for Transportation Projects,2004,126:393-402.
[6]Cai Chunsheng,Shi Xiaomin.Structural performance of bridge approach slabs under given embankment settlement[J].Journal of Bride Engineering,2005,10(4):482-489.
[7]J L Robison,R Luna.Deformation Analysis of Modeling of Missouri Bridge Approach Embankments[J].GeoTrans,2004:2020-2027.
[8]ISO 2631-1:1997Mechanical Vibration and Shock-Evaluation of Human Exposure to Whole-body Vibration[S].
[9]GB/T 13441.1-2007机械振动与冲击人体暴露于全身振动的评价第1部分一般要求[S].
[10]JTG H20-2007公路技术状况评定标准[S].
[11]Long J,Olson S,Stark T,et al.Differential Movement at Embankment-Bridge Structure Interface in Illinois[J].Transportation Research Record Journal of the Transportation Research Board,1998,1633(1):53-60.
[12]Shi X M,Cai C S.Simulation of dynamic effects of vehicles on pavement using a 3Dinteraction model[J].Journal of Transportation Engineering,2009,135(10):736-744.