Do Structural Engineers Design Using the Richter Scale Parameter?

Buildings aren’t designed for a specific Richter scale value. The Richter scale measures energy at the earthquake’s epicenter, not the shaking level at your site.

Structural engineers design for site-specific ground motions defined by codes like the International Building Code (IBC) or ASCE 7/ BNBC 2020 in Bangladesh. These codes use parameters like peak ground acceleration (PGA) or spectral acceleration values.   

 

In Dhaka, the Peak Ground Acceleration (PGA) is 0.20g on very stiff soil/rock, and according to the seismic zoning map of Bangladesh, the city falls under Zone-2 (image-1). It is important to note that PGA can vary significantly depending on several factors, including the distance from the earthquake’s epicenter, local soil conditions (soft soils tend to amplify shaking), and the characteristics of the fault. As a result, earthquakes of the same magnitude can generate very different PGA values at different locations.

Building codes prioritize "earthquake-resistant" design with a goal of life safety, not "earthquake-proof" construction that prevents all damage. The core philosophy is to control damage to acceptable levels at a reasonable cost.

In the structural drawings, we incorporate all relevant code provisions for earthquake resistance design. These must be strictly followed during construction, quality control including specifications for rebar strength and ductility, concrete strength, reinforcement detailing, and other structural requirements.