Abstract

Earthquakes occur naturally and cannot be predicted ,it occurs suddenly and because of their violent movement they have a great ability to cause great damage to structures. Due to the increasing impact of the earthquakes that recently escalated in Iraq on all kinds of civil facilities, it became necessary to conduct a study on the impact of seismicity, and because traditional seismic isolation methods for construction are very expensive, finding alternative solutions is necessary.

    This study aimed to reduce the impact of earthquakes on structures through a new damping method that involved a steel-framed building with columns, spans, and a two-way bubble deck slab. The bubble deck slab, which uses air bubbles to reduce weight and withstand pressure, was further enhanced by introducing fluids into the bubbles (The plastic spherical bubbles used in this work are manufactured in Iraq from recycled plastic) and connecting them with tubes. This modification improves the movement of the fluids inside the bubbles, providing additional damping that helps absorb seismic energy and reduce vibrations during an earthquake. Experiments were conducted using a shaking table to simulate earthquakes, with variables such as bubble diameter, number of stories, and fluid types and proportions. The results showed that the bubble deck slab, particularly when fluids were added, was highly effective in reducing the impact of earthquakes on the structure. In a single-story building, no significant damping was observed because the natural period of the building was too short to match the frequency of the seismic waves. However, in a two-story building, the addition of fluids led to substantial reductions in displacement. For example, when 50% oil (two story(D/H=0.86)) was added to both the first and second stories, displacement was reduced by 295% and 302%, respectively. Similarly, adding 50% oil (two story(D/H=0.90)) resulted in a 409% reduction in displacement in the first story and 383% in the second story. Additionally, when 50% and 75% water (two story(D/H=0.86)) were added to the first story, displacement decreased by 276% and 333%, respectively. For the same fluid added to the second story (two story(D/H=0.90)), displacement reductions of 503% and 352% were achieved.

These findings confirm the effectiveness of adding fluids to bubble deck slabs as a method for significantly mitigating seismic effects on structures.