| 论架空结构的震动 |
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| 引用本文： | 潘家铮.论架空结构的震动[J].地球物理学报,1956,5(2):153-176. |
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| 作者姓名： | 潘家铮 |
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| 作者单位： | 上海水力发电设计院 |
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| 摘 要： | 本文所謂架空結構是指搁置在較高的支墩上的連續梁結構,例如高架橋梁或水電站的架空輸水管道等。這類結構在承受震動荷載（例如地震）時,常會引起較大的變形和应力。如支墩較粗矮,則在計算較低的頻率時,其作用可近似的以一彈簧支座代替之,而忽略支墩本身的結構震動影響。這是一個常用的假定,可以使計算工作充分簡化。本文首先對這一情况作了詳盡討論,給出较完整的解答,包括起始條件影響在内,並提出用“載常數”及“形常數”的觀念來進行計算。然后本文給出考虑支墩的震動影響時的精確解答,分別就縱横方向的震動進行討論,並指出近似計算公式和精確公式间的關係,近似公式只能在支墩較剛固和計算较低階的頻率時才適用。文中列出了結構作横向諧和震動時的特別解答,可見其計算工作量將比近似法增加不少。
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| 关 键 词： | 支墩 地球物理 方程式 弹簧支座 特解 架空结构 近似公式 荷载 载常数 形常数 |
VIBRATIONS OF CONTINUOUS GIRDERS ON ELASTIC PIERS |
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| PAN CHIA-CHENG.VIBRATIONS OF CONTINUOUS GIRDERS ON ELASTIC PIERS[J].Chinese Journal of Geophysics,1956,5(2):153-176. |
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| Authors: | PAN CHIA-CHENG |
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| Institution: | The Shanghai Design Institute of Hydroelectrical Engineering |
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| Abstract: | The problem of investigating the vibration properties of continuous girders on elastic piers frequently occurs in practical design work. An approximate method of attack is to replace the elastic pier by a spring support. This method simplifies greatly the analysis and is generally adopted in practice. In the first part of this paper, this approximate method is investigated in detail and complete solutions including the effect of initial conditions are given. The computations are made more systematic and simple by the adoption of a system of constants defined as the dynamic shape constants and load constants of the structure. In the second part of this paper, the more accurate method of analysis is investigated. The exact frequency equations of the system are obtained by writing down the dynamic equations of the girders and the piers simultaneously and the boundary conditions are taken into consideration. It is shown that by taking only the fist one or two terms of the series expansions, the exact frequency equation reduces to the approximate one. It is concluded that the approximate method will give adequate solutions in the case when the piers are rigid and when only the lower frequencies of the natural mode need be considered. Particular solutions of structures under transverse vibrations are worked out and is found more involved than that given by the approximate method. |
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