Date of Publication

8-7-2024

Document Type

Master's Thesis

Degree Name

Master of Science in Civil Engineering

Subject Categories

Civil Engineering | Structural Engineering | Transportation Engineering

College

Gokongwei College of Engineering

Department/Unit

Civil Engineering

Thesis Advisor

Lessandro Estelito O. Garciano

Defense Panel Chair

Andres Winston C. Oreta

Defense Panel Member

Richard M. De Jesus
Bernardo A. Lejano

Abstract/Summary

Bridges are a significant part of road networks that continuously move supplies and people from one place to another. They are vulnerable to natural hazards like earthquakes that can cause a bridge to collapse in seconds. Seismic hazard maps are essential for designing and assessing a structure to withstand significant ground motion. The structural design and evaluation of structures are continuously updated based on the development of governing design codes and standards. The current uniform seismic hazard bridge design procedure can still be improved by incorporating the risk of a bridge collapse in a particular region. While risk-based seismic design for buildings is well-established and included in the design codes of several countries, its application in bridge performance-based seismic design is limited. Recent developments have seen the inclusion of risk-targeted ground motion concepts in the seismic design of bridges. However, these recent updates only partially cover the idea of a risk-targeted maximum-considered earthquake with a 1% probability of collapse in 50 years. In quantifying the uncertainties for risk design, this study applied incremental dynamic analysis (IDA) to produce the generic fragility curves of the reinforced concrete deck girder bridges in Manila. The IDA results determined that the record-to-record uncertainty equals 0.50, representing the RCDG bridge's collapse fragility lognormal standard deviation. The PSHA and DSHA were utilized to determine the seismic hazard at the site. Integrating the PSHA hazard curve with the collapse fragility curve using the iteration process determined the probabilistic risk-targeted ground motion (RTGM) following ASCE 7-16 procedures. The minimum of the probabilistic RTGM and deterministic ground motion obtained the risk-targeted maximum considered earthquake (MCER) values. The MCER maps were developed considering the directivity factors for the SS and S1 mapped spectral accelerations and the soil class types in Manila. These maps can produce an MCER response spectrum for designing new bridges and assessing existing ones.

Abstract Format

html

Language

English

Format

Electronic

Keywords

Bridges—Earthquake effects—Philippines; Reinforced concrete construction—Philippines; Earthquake resistant design—Philippines

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Embargo Period

8-20-2024

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