The span of a simple supported beam bridge is 36m. The beam material is C50. The area of mid-span cross section is and bending moment of inertia is . Calcula te the impulse coefficient of this bridge. 已知一座简支梁桥跨径 36m , T 型梁截面,主梁采用 C50 混凝土,跨中截面抗弯惯性矩为 ,跨中横截面面积为 ,求此简支梁的冲击系数。