ABSTRACT

Microtremor measurements were performed on four historical timber–masonry composite pagodas (called tiered temples) in Kathmandu Valley. Several measurements were performed between 2009 and 2017. The Gorkha earthquake occurred on April 25, 2015, causing severe damage (collapse, inclination, uplifting of the top tier, and damage to masonry walls) to the temples being monitored. The earthquake damage was assessed, and the results were compared with the structures’ fundamental vibration characteristics, determined using microtremor measurements. The temples, which were surveyed before and after the earthquake, exhibited an increase in the natural period of vibration and a stiffness loss of approximately 10%. For the four temples with multiple tiers investigated, linear idealisation of the natural period of vibration with the height of the structure is proposed. By including microtremor measurements conducted in previous studies, the natural periods of the tiered temples in Nepal were found to be distributed between 0.3 and 0.7 s.

摘要

对加德满都谷地的四座历史悠久的木材-砖石复合宝塔（称为分层寺庙）进行了微震测量。在 2009 年至 2017 年期间进行了多次测量。2015 年 4 月 25 日发生了廓尔喀地震，对被监测的寺庙造成了严重破坏（倒塌、倾斜、顶层抬升和砖墙损坏）。评估了地震破坏，并将结果与​​使用微震测量确定的结构的基本振动特征进行了比较。在地震前后对寺庙进行了调查，发现自然振动周期增加了，刚度损失约 10%。对于调查的四座多层次的寺庙，提出了振动自然周期与结构高度的线性理想化。通过包括先前研究中进行的微震测量，发现尼泊尔分层寺庙的自然周期分布在 0.3 到 0.7 秒之间。