What are the shape of Building of Anti Earthquake should be?

Question

Accepted Answer

The correct option is (1): Circular.
When designing structures to withstand earthquakes, the shape of the building plays a crucial role in how seismic forces are distributed and resisted. Circular or radial shapes are generally considered the most advantageous for earthquake resistance. This is because a circular building lacks corners, which are typically points of stress concentration and weakness in rectangular or square structures during an earthquake. The uniform distribution of mass and stiffness around a central axis in a circular design allows seismic waves to be absorbed and dissipated more evenly, reducing the likelihood of localized damage or structural failure. Furthermore, circular buildings do not have a preferred direction of weakness, as they present a consistent resistance to forces coming from any angle, which is ideal given the unpredictable nature of earthquake tremors.

The incorrect option is (2): Square.
Square buildings, while common, are generally less ideal for earthquake resistance compared to circular designs. The sharp 90-degree corners create stress concentrations where seismic forces can amplify, leading to potential cracking or collapse. Square buildings also tend to have a more pronounced directional vulnerability; if seismic waves align with one of their principal axes, the building can experience significant torsional (twisting) forces, which are highly destructive. The rigidity of a square shape, without proper structural detailing and damping, can make it prone to brittle failure rather than ductile yielding.

The incorrect option is (3): Rectangular.
Rectangular buildings, similar to square ones, suffer from the inherent weakness of corners in an earthquake scenario. The elongated nature of many rectangular buildings can exacerbate problems related to torsional forces, especially if the center of mass and the center of rigidity do not coincide, leading to uneven twisting during seismic events. Longer walls are also more susceptible to diaphragm action issues, where the floor and roof systems may not effectively transfer horizontal forces to the vertical resisting elements. This can result in significant deformations and damage, particularly at the ends of the building.

The incorrect option is (4): Triangular.
Triangular buildings, while presenting a unique aesthetic, are generally not favored for earthquake-resistant design. The acute angles in a triangular plan can create severe stress concentrations, making them particularly vulnerable to damage during seismic activity. The uneven distribution of mass and stiffness, with a narrow point and a wider base, can lead to complex and unpredictable responses to ground motion, often resulting in significant torsional effects. Additionally, the geometric complexities of framing a triangular structure efficiently to resist lateral forces can be challenging and costly to implement effectively.