桥头搭板的受力计算

Calculation of the Internal Force of Approach Slabs

桥头设置搭板的目的是为了实现刚柔过渡．在填土材料和施工压实度确定后，总沉降量只与填土高度有关，因此，桥头搭板的长度不应以构造物的规模为依据．搭板一般两端分别置于台后半腿和枕梁上，由弹性地基理论，将搭板视为弹性地基上的简支板，推导出在集中荷载以及均布荷载作用下搭板的位移和内力计算公式．以单位板定进行计算时，将汽车荷载视为集中力，板的自重以及铺装视为均布荷载，由公式计算出单位板宽的内力，从而对搭板进行配筋计算．这种计算方法有一定的实用价值．

The approach slab is placed to realize the transition from the rigid structure to fiexible foundation. Once stuff and degree of compaction are determined, total amount of settlement is only relted to the height of stuff, so the height of the approach slab should not be datermined according to the scale of the bridge.Two ends of the approach slab are usually placed on the bracket of bridge abutment and the seat beam, on the basis of the theory of elastic foundation, the approach slab is regarded as simple supported beam on elastic foundtion, thus the formulas of its displacement and internal force are deduced when centralized load or welldestributed load act on the approach slab. Taking the beam 1 meter wide as a model of caculation, we consider automobile load as centralized load and gravity of slab and surfacing as well-distributed load. Accordingic formulas, we can calculate internal force of slab, from this the amount of reinforcing bar in approach slab can be designed. This method is of value to practice.