ce/papers最新文献

Following several collapses, bridge management has become crucial in recent decades. In Italy, the publication of the Guidelines for Bridge Management has prompted administrations and researchers to implement new solutions: in fact, Bridge Management System (BMS) platforms, integrated with Geographic Information System (GIS) and Building Information Modeling (BIM), have been developed through commercial solutions or research projects. However, these platforms can present challenges for less experienced users: commercial platforms are often predefined and hard to customize, while research-based solutions tend to be complex and difficult to implement in practice. Consequently, the authors stress the need for easy-to-use tools for beginners, providing essential starting tools. This article proposes a simple methodology for integrating the Guidelines within Bridge Information Modeling (BrIM), offering operational tools to understand and apply BIM processes in infrastructure management. It represents a first step in a larger project to develop an open platform for road and rail network management. A BrIM template with required components, digital Guidelines sheet, and IFC export settings is provided, tested through a case study to verify the procedure's correctness and visualization with IFC viewers.

This paper presents several case studies where state-of-the-art NDT (nondestructive testing) techniques were employed to assess the condition of post-tensioned bridges' prestressing systems. The bridges, located on highways in Vienna's core urban area, are subject to heavy traffic. The paper highlights the author's accumulated experience as an expert service provider (Ramboll Finland Oy) responsible for the technical NDT assessment of these bridge inspections, and as the client (ASFINAG Baumanagement GmbH), the operator and maintainer of these critical infrastructures. Given that the prestressing system in post-tensioned bridges is vital for load-carrying capacity, its condition is essential for ensuring both the functionality and safety of the structure throughout its service life. However, because these systems are internal, the prestressing steel is not visible (unknown condition) and the quality of duct injection, which is critical for durability and functionality of the prestressing, is unknown. As demonstrated in extreme cases, corrosion of prestressing steel can lead to sudden bridge collapses. This paper discusses seven bridge inspection projects (2022-2024) in Vienna. Evaluations of duct injections were conducted in selected zones using ultrasound tomography and Impact-Echo NDT techniques. Slightly invasive methods were used to verify the NDT results and estimate corrosion of the prestressing steel.

To ensure the long-term safety, durability, and functionality of bridges, it is essential to account for the impact of thermal variations on their structural behavior. Temperature interferes by causing volumetric expansions and contractions, that when restrained also cause mechanical stresses that can impact the integrity of bridges. Understanding temperature and its effects is crucial, particularly in Structural Health Monitoring, as these influences must be isolated from overall measurements to prevent misinterpretations of a bridge's condition. Modern monitoring systems encompass sensors like thermocouples, fiber optics, and infrared imaging to capture realtime temperature data. Such systems enable the analysis of thermal gradients, long-term trends, as well as their correlation with mechanical response. This study presents the design and preliminary results of the static monitoring system of a real in operation roadway bridge chosen as a case study. The objective of the monitoring is providing continuous data on temperature-induced effects, enabling the identification of patterns and anomalies. The bridge is equipped with strain-gauges, thermocouples, inclinometers, and displacement transducers. Starting from the case study results, different methodologies for monitoring and analyzing thermal responses in bridges are explored by integrating temperature data with structural parameters to assess their correlation.

Bridge design aims at ensuring safety and serviceability of these structures. A relevant serviceability issue concerns the comfort of bridge users. Vibration serviceability of existing bridges, designed according to outdated codes of practice, can be jeopardized by insufficient consideration of this aspect, very slender structure, and increased traffic loads. Thus, a fast-testing approach to check vibration serviceability of operational bridges can contribute to prevent possible downtime because of a perceived unsafety. The present paper describes the research activities developed in the context of the national research project entitled “Vibration Serviceability Of Road bridges”. The project aims at developing a simplified approach to identify bridges prone to serviceability issues, and at quickly checking the vibration levels by means of a prototype smart car equipped with sensors. The paper describes how a database of bridges and viaducts at the regional scale can be easily obtained from geographic internet services. Basic data useful for a preliminary screening of the bridge stock with respect to possible vibration serviceability issues are collected, and a simplified verification approach is proposed based on the estimated static deflection under traffic loads and frequency of the fundamental vertical bending mode of the bridge. Finally, the paper illustrates the experimental characterization of the dynamic response of the smart car, discussing its significance for the applications.

This study investigates the detection of prestressing wire breaks (PWBs) in post-tensioned concrete girders using distributed fiber optic sensors (DFOS). Decommissioned bridge girders were used as test specimen, and a 30 m long DFOS was installed on the girder's tensile surface. The tendon was damaged at one location in seven steps, and the strain changes were measured with an optical distributed sensor interrogator (ODiSI) capable of high-resolution distributed strain sensing (DSS). The results show that PWBs can be detected and located in uncracked concrete members by measuring strain changes. However, strain changes were small, about single digit μm/m per cut wire, which is in the magnitude of the ODiSI's measurement accuracy and resolution. Thus, the transfer to application for real-world structural health monitoring use cases is still a challenge. The shape and intensity of the PWB-caused strain signal depend largely on position of the PWB and DFOS in the cross-section and the distance between them. This contribution proposes a model for the PWB-caused strain distribution in the concrete and discusses the requirements for a DSS-based monitoring concept. One important requirement is distributed temperature sensing for temperature compensation.

Italy is the 4th European country for highway km extension after Spain, Germany and France, with 85% of the network built before the 1980s.

The first Italian modern code, Ordinance No. 3274, was issued in 2003 only after a school in San Giuliano di Puglia collapsed in 2002 due to a M 5.7 earthquake. Therefore, most of Italian infrastructures have been designed according to basic, or none, seismic consideration, even those that fell in high seismic risk zones. Thus, most of the structures show structural deficiencies against seismic actions.

In 2003, the Ordinance introduced a new zonation according to a probabilistic seismic hazard analysis (PSHA) and imposed the verification, following the Eurocode 8 principles, of the strategic buildings/infrastructures.

The recent (2022) Italian ‘Guidelines for risk classification and management, safety assessment and structural health monitoring of existing Bridges’ addresses specifically non-seismic conditions leaving to the manager of the relevant asset the retrofitting strategy.

Bridges seismic retrofitting can be achieved by different solutions, adoption of seismic isolation being one of the most efficient. In this paper, the retrofitting selection criteria adopted for 2 bridges in high-seismicity zones are presented, emphasizing design issues.

Currently, a noticeable societal requirement to use the most accurate systems for assessing the reliability of existing structures and bridges is present. Especially, prestressed concrete bridges that were built in the 1960s today show serious failures. The connection between research and development in bridge monitoring has become very important. Experts are facing the need to use accurate measurement procedures and methods that will be functional directly in practice. Such applications include, for example, methods based on the principle of stress release from a prestressed member or detailed monitoring of the structure's response to direct and indirect loads. For such observations, it is possible to apply modern fiber-optic FBG (Fiber Bragg Grating) sensors purposely modified to record strains. For adequate adjustment of the measurement instrument, it is important to define the specification of the required sensor so development will be focused on the accuracy of the outputs, the frequency of recordings, and the possibility of their installation. The article describes the application of these sensors on one existing post-tensioned segmental bridge. Used sensors were developed to monitor joint openings. Finally, the advantages and disadvantages of individual applications are summarized. Such sensors can help the administrators monitor existing segmental bridges in real-time and contribute to advanced Alert Systems for early action in the case of detected problems.

In 1975, an industrial warehouse was built near Madrid, designed by three of the most prestigious Spanish architects of the time. The warehouse was intended for the storage of products for a large commercial company.

The building, covering approximately 40,000 m² with a symmetric, almost square floor plan, is a remarkable example of functional rationalist brutalist architecture. It was constructed using beamless reinforced concrete slabs and precast prestressed elements, addressing around 700 linear meters of loading docks around the perimeter. It features two large internal storage courtyards surrounded by internal access roads distributed across five levels.

The building was constructed during a period of technological innovation in structural concrete, with the development of new calculation methods and materials, such as high-strength steel (cold-drawn and naturally hardened) and precast prestressed steel elements.

However, as was common at the time, durability was not a key factor in the design or construction of the structure. This, combined with the fact that the building went out of use in the mid-1990s, never underwent significant rehabilitation work, and suffered from severe degradation of the roof's waterproofing, led to a series of deterioration processes that now affect its remaining service life.

The assessment of the building's structural capacity was hampered by the lack of descriptive documentation regarding the structure and its reinforcement schemes. Therefore, an extensive investigation campaign was necessary to analyze the structure and its constituent materials.

Mapping existing concrete structures in digital methods such as Building Information Modeling (BIM) is currently a challenge. Over years of operation, the actual conditions of structures can sometimes differ greatly from the originally planned states. However, these deviations are not yet integrated into BIM, limiting the ability to represent them efficiently. One option is to create an object catalogue that takes these altered conditions into account and provides users with a simplified yet accurate representation. This article presents and discusses an approach to achieving this integration.

In continuous Structural Health Monitoring (SHM), environmental and operational conditions significantly influence damage detection strategies. To accurately identify damage and avoid false alarms, statistical patterns must be calibrated under healthy structural conditions to distinguish changes in dynamic response caused by damage. Typically, SHM systems require thermocouples to measure temperature for such calibration. This study proposes an experimental approach to estimate the first natural frequency of structures based solely on the air temperature. Using a dataset of 13 Prestressed Reinforced Concrete (PRC) bridges, a bilinear regression model is developed to relate natural frequency to temperature, distinguishing behaviours above and below the freezing point. Additionally, a nonlinear regression model is derived linking natural frequency to span length. Ultimately, a unified equation that incorporates both span length and temperature is presented, with prediction intervals. The model's reliability is validated using data from an independent bridge.