钢筋混凝土塔架是土建工程中常见的一种结构。采矿用的提升井架、化工厂用的各种类型的高塔常常采用这种型式。在地震区兴建塔架时,一般仅用经验公式计算塔架的基本周期,略去了高振型对地震荷载作用。但是对于结构型式特殊或者高度较大的塔架,上述经验公式就不合适。此外,工程中常遇见五、六十米或更高的塔架,其平面尺寸不大,有些甚至还不设置围护墙体,塔架的基本周期可长达—秒以上,应用上述方法 Reinforced concrete towers are common structures in civil engineering. Mining derricks and various types of towers used in chemical plants often use this type of pattern. When constructing a tower in an earthquake zone, the basic cycle of the tower is generally calculated using only an empirical formula, and the effect of high vibration mode on the seismic load is omitted. However, for towers with special structural types or large heights, the above empirical formula is not suitable. In addition, towers with a height of five or sixty meters or more are often encountered in the works. The planes are not large in size. Some of them are not even provided with fence walls. The basic cycle of the tower can be longer than -2 seconds. The above method is applied.