1、移動(dòng)荷載 Moving loads
移動(dòng)荷載:方向、大小不變，僅作用位置變化的荷載 direction and magnitude don’t change, only positions change (moving load)如橋梁上行駛的車輛，工業(yè)廠房中吊車梁上開動(dòng)的行車等, for instance the moving cars on bridges, the cranes in factories。
結(jié)構(gòu)承受移動(dòng)荷載作用時(shí)，其反力、內(nèi)力以及位移等均隨荷載作用位置的變化而改變。Under the moving loads, the reactions , internal forces and displacements of structures will change with the movement of the loads
為解決千變?nèi)f化的移動(dòng)荷載作用下結(jié)構(gòu)的設(shè)計(jì)問題，基于線彈性結(jié)構(gòu)的疊加原理，如果掌握了單位移動(dòng)荷載下結(jié)構(gòu)的反力、內(nèi)力與位移變化規(guī)律，則任意移動(dòng)荷載下的反力、內(nèi)力與位移可用疊加方法獲得。
For the solution of problems of design of structures, based on the superposition principle of linear elastic structures, if we know the variation laws of the reactions , internal forces and displacements , then the reactions , internal forces and displacements under any moving loads can be determined by superposition principle
定義Definition: 單位移動(dòng)荷載作用下，結(jié)構(gòu)反力、內(nèi)力或位移等隨荷載位置變化的函數(shù)關(guān)系，分別稱為反力、內(nèi)力、位移的影響系數(shù)方程，對(duì)應(yīng)的函數(shù)圖形分別稱為反力、內(nèi)力、位移的影響線（Influence Line 縮寫為 I .L.）。
under the action of unit load, the functional relations of the reactions , internal forces and displacements of structures with the unit load position are called the influential coefficient equation, and the corresponding function graphs are called the Influence Line of the reactions , internal forces and displacements of structures.
為了方便，以下把反力、內(nèi)力和位移均稱為量值或物理量。For the convenience the reactions , internal forces and displacements of structures called parameters
