What is Seismic Evaluation?

In the aftermath of major earthquakes, the Japanese government investigates the causes and updates the Building Standard Act based on newly identified structural vulnerabilities. One of the most significant revisions occurred in May 1981, introducing the “New Seismic Design Standards,” which form the basis of current regulations.

Seismic evaluation assesses whether buildings designed before these standards are vulnerable to major earthquakes. The process involves checking the building’s structural configuration, materials, and overall condition against current codes. It helps identify potential risks—such as seismic irregularities in plan or elevation, aging or weakened structural elements, and insufficient lateral resistance.

Why It Matters
Seismic evaluation provides a technical basis for determining whether structural reinforcement is needed and where it should be prioritized. By comparing the building’s current seismic performance with modern standards, the evaluation helps quantify risk and guide retrofit decisions. This not only improves safety for occupants but also supports continued building use, regulatory compliance, and long-term asset value—making it a critical step in the responsible management of aging infrastructure.

Evaluation Process

Review of Existing Documents and On-site Investigation

The process begins with a detailed review of the building’s original design documents and structural calculations. This step helps us understand the design intent and identify materials used during construction.
We then conduct an on-site survey to verify whether the current structure matches the original drawings. In addition, we extract concrete core samples and perform compressive strength tests to assess material properties and the extent of any deterioration over time.

Preliminary Calculations

Using the results from the on-site investigation, we recalculate loads that reflect the building's current condition, including vertical and seismic forces.
For structural members with built-up or non-standard sections, we determine cross-sectional properties and evaluate their strength and ductility.

Seismic Evaluation

We develop an analytical model of the structure based on both the original design and on-site findings.
Simulations are performed to determine how individual members behave under seismic loading, and how their failure might impact the overall stability of the structure.
We then assess the building’s lateral load-bearing capacity and seismic performance, considering degradation, configuration, and overall force distribution.

Seismic Reinforcement

If the building’s seismic performance is found to be inadequate, we propose retrofit measures tailored to the site conditions.
For buildings that remain in use during retrofitting or have spatial constraints, we explore alternative reinforcement strategies that maintain safety and functionality without requiring extensive modifications.

Our Approach to Seismic Evaluation

At RISE, we recognize that seismic evaluations—particularly in operational plant facilities—can significantly impact ongoing maintenance activities, established procedures, and project timelines. These evaluations may lead to expanded construction scopes, required updates to existing design documents, and the need to adjust maintenance protocols.

Understanding the likelihood of increasing the cost and the time, we prioritize early and ongoing communication with all stakeholders. From the initial planning stages, we work collaboratively with facility managers, maintenance teams, and project owners to align structural safety goals with practical site constraints.

When uncertainties arise or specific concerns are raised, our engineers make site visits to provide technical explanations directly. By ensuring a shared understanding across all parties, we support informed decision-making and promote the successful integration of seismic upgrades with minimal disruption.