Developers

1. Amin Ghasemi, MSc.
2. Dr. Mojtaba Mahsuli, Associate Professor
3. Dr. Homayoon E. Estekanchi, Professor
4. Dr. M. Ali Ghannad, Professor

CIRA objectives

This project puts forward a functional tool for evaluation and communication of risk to building structures under the earthquake hazard. For this purpose, a web-based system is designed and implemented. The system is a practical effort to raise public awareness of the monetary and social aspects of the seismic risk. The need for such developments stems from recognition that in many earthquake-prone regions, such as Iran, there is a lack of deep concern amongst the public about the earthquake hazard. Upon occurrence of a strong ground motion, the public becomes conscious of the importance of better adherence to seismic guidelines in design and higher quality of construction, but this consciousness erodes over time, at least until the next severe earthquake event. The academic community has a social duty here, and that is to convey the results of scientific studies in layman’s terms to the public. Probabilities, costs, and death toll are metrics comprehensible to the non-technical audience. Therefore, risk in the proposed system is defined as the probability of exceedance for monetary and social losses, i.e., costs and casualties, respectively. The worldwide web is selected as the medium for this communication because of its omnipresence and ease of access for the public.

The fundamental vision for the proposed system is to communicate the risk to three groups of audience: Building owners, engineers, and policy-makers. A building owner inputs to the system a set of preliminary, observable information about the building, such as location, material, number of stories, footprint area, year of construction, and load bearing system. The system will input this information into a simlified risk analysis approach. This approach predicts the mean repair cost and the mean number of casualties. The result is displayed and interpreted for the owner in the output of the system. For instance, the owner will know the odds of death for the building occupants as well as the average repair costs, which significantly illuminates her/his views of the risk involved.

In contrast to the simple interface for a non-technical user, it is envisioned for the system to provide the engineers with a more detailed interface. It essentially lets the engineer define an idealized structural model for the building. The model is then utilized in a more detailed risk analysis methodology based on reliability analysis and multiple interacting probabilistic models.

The simple and intuitive interface of the system is aimed to foster the use of probabilities in engineering practice. Using this system, engineers will be able make rational, risk-based decisions on the selection of structural systems and design of the building under consideration. This will result in an added value in engineering practice.

The scope of the system is currently limited to building structures. To quantify the uncertainty in the earthquake intensity, the system adopts the probabilistic seismic hazard analysis results from the literature. Such results are limited for cities other than Tehran. Hence, pending in-house hazard analysis, the system only provides services to the residents of Tehran. In passing, it is noted that hazard means the probability of exceeding a measure of intensity.