Throughout the last century and in recent years, several bridge failures have taken place worldwide. Recent studies uncovered that the primary cause of these collapses was human errors in the design, construction, and operation phases. Regardless of this finding, there is still a considerable gap between this information and the known errors and the risk they represent for structural safety. Aiming for a better understanding of human errors, an identification procedure and a qualitative assessment of such errors considering risk-based indicators (probability of occurrence and consequence) was performed. Several brainstorming meetings with design and construction experts led to the identification of 49 relevant human errors, which were listed for further evaluation on a survey. Much more important than identifying and assessing these errors is identifying those that pose a greater threat to safety. Using a decision-making tool (analytical hierarchy process) to process all the information collected in the survey, the errors were ranked according to risk indicators. Furthermore, a qualitative risk assessment is performed, allowing the identification of the errors denoting higher risk for structural safety, according to experts’ opinions.

The economic and social losses due to increasing bridges collapse over the years have underlined the importance of the development of more robust bridge structural systems when exposed to harmful events, such as natural hazards, human-made hazards and human errors. Natural and human-made hazards are usually explicitly addressed in the numerous works available in the literature, but when it comes to human errors, very few studies can be found. It is worth mentioning that human errors have been identified as one of the main causes of bridges failure. Consequently, the main goal of this paper is the assessment of human errors impact on the robustness and safety of a prestressed reinforced concrete bridge through a probabilistic-based approach. Uncertainties concerning the numerical model, material strength, geometry and loading condition are used as key input parameters for the probabilistic assessment. Considering the structural system performance in its early days (i.e., virgin reliability index) the human error impact in structural safety is measured according to the structural system performance reduction given different errors with different magnitudes. Therefore, the structural system ability to maintain acceptable levels of performance, given such errors, is assessed.

The long-term quality assurance of bridges demands an adequate quality control plan detailing the main required activities and assessment tools. This paper presents the application of a quality control plan on two existing reinforced concrete bridges located in Portugal and North Macedonia. Based on the available results from visual inspections and non-destructive tests, defects and corresponding damage processes were identified. The structural safety of the case studies was assessed by means of a reliability index considering the identified damages. The reliability index computation was supported by a nonlinear finite element analysis. The computed reliability index that reflects the actual (‘today’) bridge condition was used as the base information in the preparation of possible maintenance scenarios. Three different maintenance scenarios were considered, namely, the improvement (corrective scenario), reduction (do nothing and rebuilt scenario), or delay in the reduction (preventative scenario) of the performance of the structure. By comparison of normalised net present values of the key performance indicators (reliability, safety, availability and costs), the most appropriate scenarios are found.

The stability of slender columns is a topic that has been dealt with in research and practice for many years. The importance of this topic also increases with the possibility of using non-linear modeling approaches to determine the stability and with the increasingly complex safety formats. In order to show the complexity and the variability associated with the non-linear models, two previous contributions discussed and compared (a) the results of the Round Robin Non-Linear Modeling, and (b) the existing international associated standard specifications and safety concepts with respect to experimental results. The aim herein is to determine the reliability level (safety index) on the basis of these investigations and findings and to examine the existing safety formats of classical and extended probabilistic analyses and to derive any necessary adjustments. In addition, the method of the safety format Estimation of Coefficient of Variance of resistance (ECOV) is used for the determination of the global safety resistance factors based on the non-linear analyses’ findings of the Round Robin modeling partners.