The fundamental period of structures is a parameter used in structure under design and for evaluating existing structures. Data-driven methods using ambient vibrations have become popular, particularly for the adjustment of empirical relationships applied to building classes. This study presents the results of a survey of ambient vibrations performed in 146 reinforced concrete buildings in the center of Quito (Ecuador). Classical functional forms giving period (T) for height (H) or number of floors (N) are derived and compared with the relationships available in the Ecuadorian seismic design provisions. We highlight variations in the empirical relationships according to soil conditions, but above all according to the date of construction and the historic seismic sequence to which the buildings have been exposed. The cumulative damage effect is finally confirmed by repeating ambient vibration measurements after the 2016 Mw 7.8 Pedernales earthquake located in the subduction zone, about 175 km from Quito. Even with such a long epicentral distance, leading to low macroseismic intensity (I_EMS98 = IV), the seismic ground motion of between 0.017 and 0.081 g recorded in Quito reduced the resonant frequency of the buildings tested by between 2 and 13%. This confirms the effect of cumulative damage in reinforced concrete buildings located in seismic zones, even for weak ground motions, and the variability of empirical T/H relationships associated with damage.

中文翻译：

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修改位于地震多发地区（例如基多（厄瓜多尔））的建筑物的数据驱动的周期/高度关系

结构的基本周期是在设计中的结构中用于评估现有结构的参数。使用环境振动的数据驱动方法已变得流行，尤其是对于调整应用于建筑类的经验关系而言。这项研究提出了对在基多（厄瓜多尔）中心的146栋钢筋混凝土建筑进行的环境振动调查的结果。得出了古典函数形式，给出了高度（H）或层数（N）的周期（T），并与厄瓜多尔地震设计规定中可用的关系进行了比较。我们重点介绍了根据土壤条件而变化的经验关系，但最重要的是根据建造日期和建筑物所经历的历史地震序列。通过在距基多约175公里的俯冲带2016年Mw 7.8 Pedernales地震后，重复进行环境振动测量，最终证实了累积破坏效应。即使震中距离这么长，导致大地震强度也很低（I_EMS98  = IV），基多记录的0.017至0.081 g的地震地震动使测试建筑物的共振频率降低了2％至13％。这证实了即使在弱地震动下，位于地震带的钢筋混凝土建筑物中累积损坏的影响，以及与损坏相关的经验T / H关系的可变性。