About the project

Seismic fragility of existing road bridges, accounting for their actual condition

ROBUST addresses the seismic fragility of existing road bridges by explicitly accounting for their actual structural condition.

The research combines the identification of representative bridge typologies, assessment of key seismic performance indicators, condition-based numerical modelling and probabilistic fragility analysis. The expected outcomes include condition-dependent seismic fragility curves and practical recommendations for bridge inspection and seismic assessment.

Objectives

What ROBUST sets out to achieve

The main objective of ROBUST is to develop a scientifically sound and practically applicable methodology for condition-dependent seismic fragility assessment of existing road bridges in Croatia.

The project focuses on identifying representative bridge typologies, defining key seismic performance indicators, evaluating the influence of structural condition on seismic response, and developing condition-dependent fragility curves. The results aim to support more reliable seismic assessment and informed decision-making in bridge infrastructure management.

Methodology

How the research is carried out

The ROBUST methodology integrates bridge inventory analysis, historical design information, field investigations, advanced numerical modelling and probabilistic seismic assessment.

Visual inspections and non-destructive testing provide information on actual structural condition, while field measurements and finite-element model updating support the development of realistic numerical models. Nonlinear dynamic analyses are subsequently used to derive condition-dependent seismic fragility curves, accounting for uncertainties in structural properties and seismic demand.

Work packages

Five interconnected work packages

The ROBUST research programme is organised into five interconnected work packages, covering the entire process from bridge characterisation to seismic fragility assessment and knowledge transfer.

WP1

Croatian Bridge Stock Characterisation and Identification of Representative Bridge Typology

Analysis of existing bridge inventories and identification of representative structural typologies considering construction periods, design characteristics and structural systems.

WP2

Key Seismic Performance Indicators

Identification of key parameters affecting seismic performance, combining historical design characteristics with structural condition data obtained through visual inspections and non-destructive testing.

WP3

Numerical Modelling and Model Updating

Development and calibration of nonlinear finite-element models incorporating structural condition, material properties and field measurement data.

WP4

Capacity vs Demands for Fragility Assessment

Evaluation of seismic demand and capacity through nonlinear dynamic analyses and derivation of condition-dependent seismic fragility curves at component and system levels.

WP5

Dissemination and Knowledge Transfer

Dissemination of research findings through scientific publications, international conferences and workshops, together with the development of practical recommendations for infrastructure managers.

ROBUST project workflow: work packages WP1 to WP5, their timeline over 36 months and the main annual results
ROBUST project workflow: work packages, timeline and main annual results.