The shear strength of reinforced concrete members without transverse reinforcement remains a critical design issue, particularly for thick and slender structural members where pronounced size effects may significantly reduce the nominal shear strength. This study investigates the combined influence of member depth, concrete compressive strength, and longitudinal reinforcement ratio on the shear capacity of beams without stirrups through nonlinear finite element analyses (NLFEA). Beam depths ranging from 1000 mm to 4000 mm and concrete strengths between 30 MPa and 50 MPa were considered, together with variations in different longitudinal reinforcement ratios. The numerical results confirmed a clear deterministic size effect, with nominal shear stresses decreasing systematically as the effective depth increased, while the influence of compressive strength was found to be secondary. The depth-dependent response was successfully represented using Ba & zcaron;ant's energetic Size Effect Law (SEL Type II), and the calibrated parameters provided an excellent fit to the numerical database. Furthermore, the numerical predictions of shear capacity were compared with major design provisions, including ACI 318 (2014 and 2019), Eurocode 2 (EN 1992-1-1:2005 and EN 1992-1-1:2023), and fib Model Code approaches with levels of approximation (LoA) 1 and 2. The results highlight that older formulations such as ACI 318-2014 and EN 1992-1-1:2005 tend to be unconservative for deep members, whereas EN 1992-1-1:2023 offers significantly improved agreement with reduced scatter. Among the evaluated expressions, fib Model Code LoA1 was the most conservative, while LoA2 provided the most accurate overall predictions. The findings emphasize the importance of incorporating size-effect considerations in modern shear design models, particularly for large reinforced concrete structures such as bridge decks, thick slabs, and dam walls.

Linear elastic finite element analyses (LEFEAs) have become more frequent in the design and assessment of reinforced concrete slabs under concentrated loads, as they enable low-cost evaluation of the distribution of shear forces over critical sections. However, few publications have addressed the benefits of combining LEFEA with mechanical-based models to predict the most critical shear failure mechanism and the corresponding shear and punching capacities. Notably, most previous studies employed a similar approach for a specific boundary condition or evaluated only the one-way shear capacity of slabs under concentrated loads near line supports. This study investigates the accuracy of the expressions based on the critical shear crack theory (CSCT) combined with LEFEA to assess the shear and punching capacity of one-way slabs under concentrated loads. Since such slabs may develop different failure mechanisms, this study also evaluates the level of accuracy to predict the governing shear failure mechanism identified in the tests, a topic rarely discussed until now. For this purpose, a dataset of 112 experiments was selected, covering different boundary conditions and loading arrangements. LEFEA was used to evaluate the uneven distribution of shear forces and bending moments on the critical shear regions. Some outputs from LEFEA were used in the analytical calculations with the CSCT-based expressions to predict the shear and punching capacity of such tests. The use of LEFEA also aided in understanding the change of shear failure mechanisms according to parameters such as the member width to load size ratio b slab/l load and the shear slenderness a v/d l. The combination of the CSCT expressions with the LEFEA allows for predicting the governing shear failure mechanism and the shear capacity of the slabs for most tests accurately at a low computation cost. When the governing failure mechanism was not correctly identified, a conservative estimate of the shear capacity was provided, which is desirable in such cases.

Reinforced concrete structures (RCSs) serve as critical components of national infrastructure, supporting key sectors such as transportation, energy, and water supply. However, the deterioration of these structures poses significant challenges due to its impacts on resource consumption, environmental sustainability, and public safety. This paper presents a comprehensive assessment of durability deterioration mechanisms affecting RCSs, with a focus on how climate change exacerbates these processes. A structured framework is proposed to identify, categorize, and prioritize deterioration causes based on structure type, location, and environmental conditions. A case study of a roadway RC bridge in Ecuador demonstrates the framework’s application, highlighting how critical, significant, and minor deterioration causes are evaluated and prioritized to optimize resource allocation and guide future vulnerability and risk assessments.

This paper proposes a framework for interpreting bridge field data with a focus on overall bridge performance, damage quantification, and data-driven decision-making. By leveraging recent advancements in bridge load testing, structural monitoring, and non-destructive evaluation, along with the development of interoperable platforms for bridge management, this paper synthesizes these insights into a cohesive framework. It also explores the long-term storage and utilization of data to inform future bridge management decisions. The proposed framework is designed to be flexible, accommodating varying timeframes (both throughout the bridge’s service life and duration data collection) and different types of data. Ultimately, this conceptual framework aims to assist bridge owners in making informed decisions regarding field interventions and enhance their overall decision-making processes.

Proof load testing (PLT) offers a valuable and sustainable alternative to analytical approaches for improving knowledge on the safety level of existing bridges, providing an in-situ measurement of structural bearing capacity under actual traffic loads by reducing resistance uncertainties and associated probability of failure if the test is passed. The present paper investigates the influence of the PLT on the structural reliability of prestressed concrete I-type simply-supported decks representing the most common type of existing bridges in Italy. By supplying data on the lower-bound of the capacity distribution, the PLT turns into an updated estimation of the bridge reliability. A fully-probabilistic analysis is developed combining random uncertainties on both materials and load effects with epistemic uncertainties. A traffic load model variable based on Eurocode Load Model 1 effects is calibrated to provide consistent modelling with code-prescribed safety levels. Structural capacity of the edge girder is considered both in terms of ultimate limit state for flexure and shear and serviceability limit state in terms of cracking load which could affect long-term bridge durability. The manuscript main contribution lies in developing a reliability-based approach to PLT that accounts for both prior (before test) and posterior (after test) structural reliability, incorporating conditioning on the success of the test. A sensitivity analysis according to the partial safety factor method is presented to investigate the impact of different proof loads assuming different Capacity-to-Demand Ratios (CDR). A case-study bridge is investigated where a proof load was executed recently demonstrating the benefit of the PLT in case of CDR lower than unit. The case study also showcases the possibility to significantly reduce the failure probability during the test when the target level is imposed with a number of intermediate levels of load steps.

Despite the low probability of occurrence, fire events area major hazard for structures, which can severe socio-economic impact. Although reinforced concrete (RC) tunnels are an important component transportation infrastructure, their structural behaviour under high temperatures is not yet fully understood. This study investigates the thermo-mechanical response of tunnels subjected to fire using nonlinear element analysis (NLFEA). For this purpose, recent experimental tests of large-scale reinforced concrete with and without fire protection are simulated. Different modelling strategies are discussed, and a description of the constitutive model employed is presented. Then, model-to-model and model-to-experiment comparisons are conducted to identify the advantages and limitations of each approach. The demonstrate the relevance of proper spalling modelling on the tunnel's temperature distribution. The also show a good agreement with the experimentally observed damage patterns. Finally, recommendations regarding modelling choices and further research topics are discussed.

Work–life balance (WLB) in academia remains a challenge as a result of increasing workloads, precarious employment, and expectations of constant availability. The COVID-19 pandemic exposed these structural barriers to work–life balance in academia and also clearly showed the inequities related to hybrid and remote work for women, caregivers, and underrepresented minorities. This paper highlights the key factors that pose challenges to WLB in academia, how these challenges have been worsened by COVID-19, and what we can learn from pandemic times solutions to devise inclusive practices for long-term structural change. The methodology used in this paper is a critical review of 298 published articles. This review is structured as follows: The structural barriers, inequities, and workplace policies that impact academic WLB are first inventoried. Then, the lessons learned from the pandemic are studied by dividing the short-term disruptions from the permanent shifts. Finally, inclusive solutions, focusing on institutional boundary-setting, workload redistribution, hybrid work policies, and mental health support are presented. This paper makes three key contributions: (1) it provides an intersectional understanding of WLB, accounting for gender, caregiving, ethnicity, migration, and social class; (2) it frames COVID-19 as a driver for structural reform, rather than an anomaly; (3) it bridges WLB research and policy design, proposing actionable strategies for universities and policymakers. By placing equity and inclusion at the core of the analysis, this work advocates for systemic solutions that promote a sustainable academic environment aligned with principles of social justice.

As infrastructure continues to age and traffic levels intensify, there is a growing need for efficient methods to verify the reliability of many existing structures. Field testing offers the possibility to assess the current condition of a structure. Specifically, in a proof load test, substantial loads are applied to evaluate the structure's resistance to future loads that could compromise structural safety. However, to prevent excessive test loads and their potential damage, it is desirable to assess structural reliability by monitoring the response under more moderate loads. This study merges laboratory and in-situ testing results through a Bayesian update of the structural reliability after each successful load application. Two case studies are presented where laboratory testing on structurally similar elements and analytical modelling provide ample evidence to justify test load reductions of 20 % and 25 %. The proposed method offers a systematic framework to link the structure's response during testing to structural reliability and address the uncertainties in resistance, loads and measurements. Nonetheless, the representativeness of the data in terms of structural similarity and uncertainties related to measurements continue to be significant factors. Despite these challenges, incorporating monitoring data during proof load testing is expected to reduce target loads in most cases.

To meet the sustainable development goals, novel concrete mixes are necessary. Natural fibers are becoming an interesting new element for concrete mixes, because these fibers are biomaterials recovered from residual biomass and fit in the concept of the circular bioeconomy. In this paper, we catalogize research insights on concrete mixes with natural fibers, and pay special attention to natural fibers that are available in the Metropolitan District of Quito, Ecuador, to use local bio-based materials. We focus on examining information from the literature on how natural fibers influence the mechanical properties of concrete, namely the tensile, compressive, and flexural strength. Based on this analysis, we have developed recommendations on which natural fibers are of interest for further experimental research, with the aim to develop sustainable concrete mixes for Quito. Moreover, this paper gives insights in how natural fibers influence the mechanical properties of concrete and proposes a framework that translates to other regions and cities for the selection of local and adequate natural fibers.

As the existing bridge stock is aging, the task of assessing these bridges becomes increasingly important. One of the assessment methods for existing bridges is load testing. Improvements in the field of diagnostic load testing are related to the use of numerical models. Improvements in the field of proof load testing focus on the safety of the execution of the test as well as the required load in the test. What is still lacking is a reflection of these recent advances in the codes and guidelines used for load testing of bridges. Two approaches are proposed to address this lack. The first approach attempts to answer fundamental questions with regard to bridge load testing through research. The second approach is to coordinate efforts and facilitate collaboration and exchange of ideas internationally through the IABMAS Technical Committee on Bridge Load Testing. In conclusion, it is expected that these efforts will form the basis of improved recommendations for the assessment of concrete bridges by load testing to be included in codes and guidelines and to serve the community of engineers faced with the task of assessing ageing infrastructure.

Bridges, essential for economic and social development, face significant deterioration due to aging and environmental factors. Consequently, assessing the condition of reinforced concrete bridges is essential to anticipate their future performance and optimize maintenance, rehabilitation, and replacement needs. While traditional visual inspections are widely used, the integration of unmanned aerial vehicles (UAVs) presents a more efficient approach, particularly in inaccessible areas. This article presents a comprehensive evaluation of the condition of a bridge over a decade through a case study in Ecuador. The assessment revealed significant deterioration in several structural elements, especially the substructure and road elements. These findings underscore the urgent need to improve maintenance practices and integrate advanced inspection techniques to ensure the safety and longevity of bridges in Ecuador.

At ACI Avances en Ciencias e Ingenierias, we care deeply about open science. After all, we are an open access journal that does not charge an article processing charge, and all editors are volunteers who support open science practices. Our hosting and administrative costs are funded by Universidad San Francisco de Quito. In a new effort to strengthen our open science practices, we have launched a Preprints server, named Preprints ACI. Authors who send an article to ACI Avances en Ciencias e Ingenierias are encouraged to deposit their article as a preprint on the server. Authors from within and outside the community of Universidad San Francisco de Quito are also welcome to use our preprint server.