Procedures for the assessment of highway structures

The Baltic Journal of Road and Bridge Engineering, 2018

Deterioration of bridges due to ageing and higher demands, induced by increased traffic load, require the development of effective maintenance policies and intervention strategies. Such concern should be aimed at ensuring the required levels of safety, while optimally managing the limited economic resources. This approach requires a transversal advance; from the element level, through the system level, all the way to the network level. At the same time intervention prioritisation based on the importance of the system (bridge) inside the network (e.g. highway), or of the single structural element inside the bridge is dependent. The first step in bridge condition assessment is the verification of safety and reliability requirements that is carried out using the traditional prescriptive (deterministic) approach or the current performance- based (probabilistic) approach. A critical issue for efficient management of infrastructures lies in the available knowledge on condition and perform...

2017

This article is based upon the work from COST Action TU1406, Quality specifications for roadway bridges, standardization at a European level (BridgeSpec), supported by COST (European Cooperation in Science and Technology).

Improved and more continuous condition assessment of bridges has been demanded by our society to better face the challenges presented by aging civil infrastructure. Indeed, the recent collapses of the Hintze Ribeiro Bridge that killed 59 people, in Portugal, and the I-35W Bridge in the United States, that killed 13 people, pointed out the need for new and more reliable tools to prevent such catastrophic events. Besides those events, the financial implications and potential impact through optimal bridge management are vast. For instance, facing an ageing infrastructure, the United Kingdom Government’s 2010 Infrastructure Plan signaled the need for enormous investments in infrastructures, equivalent to £200 billion over the next five years. On the other hand, the American Society of Civil Engineers reports the cost of eliminating all existing US bridge deficiencies at $850 billion. These values clearly show that planned bridge maintenance can lead to considerable savings. In the last ...

2016

From an ideal point of view, bridges should be designed, constructed and operated in such a way that they fulfil requirements from the fields of function, economy, environment, society, and culture. The present thesis wants to contribute to this matter by illuminating the manifold requirements and by developing a practicable approach to multi-objective maintenance planning for bridges. Starting with a literature review and a survey on practical maintenance planning by bridge owning agencies in Hamburg (Germany) and Chennai (India), the investigation reveals that until today practical approaches for the identification of bridge specific requirements as well as for strategy assessment and evaluation are not at hand. Instead of accounting for the whole range of performance aspects, the current investigations of maintenance strategies are commonly confined to functional and economic aspects. In exceptional cases where societal, cultural and also environmental issues are considered, thes...

Structural Engineering International, 2013

Transport infrastructure plays an important role from an economic and management point of view in every country. In developing countries, transport infrastructure has a prominent position in advancing industry and society. Recent developments show that attention should be moved from the design of new structures towards the repair and reconstruction of existing ones to ensure and increase their satisfactory structural reliability and durability. The problem is very urgent because many construction projects, especially transport infrastructure, in most European countries are more than 50-60 years old and require rehabilitations based on objective evaluations. Modified reliability levels for the evaluation of existing bridges were derived on the basis of activities in the department of structures and bridges. The levels are used for determining partial safety factors for resistance depending on the age of the bridge and on its remaining lifetime. New modified reliability levels for the evaluation of existing bridges also affect the partial safety factors for load effects.

2012

U.S. engineers need advanced tools and protocols to better assess and assure safety and serviceability of bridges. The Federal Highway Administration, American Association of State Highway and Transportation Officials, and National Cooperative Highway Research Program sponsored a scanning study of Europe to identify best practices and processes to assure bridge safety and serviceability. The scan team found that the European highway agencies expect their bridge programs to not only ensure user safety, but also to meet serviceability expectations and enhance capital investment decisions. The team gathered information on safety and serviceability practices and technologies related to design, construction, and operations. Team recommendations for U.S. implementation include developing a national strategy to increase use of refined analysis for bridge design and evaluation, encouraging States to use refined analysis combined with reliability analysis to avoid unnecessary rehabilitation or replacement of bridges, and encouraging adoption of the concept of annual probability of failure to quantify safety in probability-based design and rating specifications.

Journal of Infrastructure Systems, 2018

Bridge quality control plans and asset management systems are often integrated in collective frameworks used by authorities nationally and internationally. Similarities among these frameworks include the utilization of performance indicators for quality appraisal. However, there are discrepancies in the ways such frameworks are researched, developed, and applied. Additionally, there are problematic aspects even in their common characteristics, like the relative absence of correlation between observed performance indicator values and benchmarked ones, and the deliverables’ disparity due to the diversity of the quantified indicator variables. For the alleviation of such problematic aspects, this paper presents a bridge quality appraisal methodological and computational framework. It builds on (1) the adaptation of the sustainable building methodology and its combination with expert input solicitation methods and the research findings of the European Cooperation in Science & Technology (COST) Action TU1406, and (2) a multi-input adaptation of the analytical hierarchy process. The methodology is presented in terms of its general procedural steps and calculating requirements, and then it is tailored to reinforced concrete overpass roadway bridges. The methodology’s application in a real case study concludes the presented research.

Bridges are designed and built for a scheduled service life of 100 years. At tender stage decision making should no longer only be based on construction costs but on a holistic assessment with regard to sustainability aspects. In the German research project “NaBrü” a bottom-up approach was applied. Within the project environmental and economic aspects were assessed with the methods of LCA (Life-Cycle Assessment) and LCC (Life-Cycle Costing). In addition to LCA and LCC external effects were investigated in detail. Three different types of reference bridges and additionally different construction variants were studied over the entire life-cycle. Based on the results specific characteristics of bridges were pointed out regarding sustainability assessment. In this paper the current state of the art of sustainability assessment for bridge constructions in Germany is shown. Recent research results are summarized and conclusions for highway bridges given.

Bridge Maintenance, Safety and Management, 2012

The existing stock of road and railway bridges in Italy and in most European countries frequently exhibits insufficient performances, both in terms of structural safety and functionality, compared to the current demands coming from modern structural codes, transportation systems and necessity of reducing the costs of maintenance. Quick and reliable methodologies are then needed to assess the specific vulnerability of any bridge typology, in any possible environmental and operating conditions. In the first part of the paper the application of such type of methodologies to both road and railway transportation infrastructure in Italy is described showing that, e.g., masonry arch bridges are usually quite robust structural systems, r.c. bridges generally present durability problems and are vulnerable to seismic actions, steel bridges, other than presenting durability problems, are particularly vulnerable to fatigue. Typical retrofitting interventions considered in these studies are also briefly presented. In the second part of the work significant case studies of retrofitting interventions are in more detail described, focusing on four existing r.c. bridges, which represent an homogeneous set, all of them being part of the post-II nd World War reconstruction on the Adige River (the second longest river in Italy). These bridges are examples of some of the most usual typologies adopted in that historic period, and the defects they evidenced after fifty years of service life were typical of these kind of structures, being often the consequences of a poor maintenance and the lack of durability rules in the original design. The refurbishment interventions are presented outlining a methodological approach, which takes into account the typological characteristics of the structure, the state of maintenance, the functional requirements and the environmental aspects connected to the repair and strengthening system.

Sustainability analysis should serve to ensure that one structure can be built as sensible as possible for the present and for future generations regarding the three columns of sustainability. The reason why sustainability criteria at the time have hardly any influence on the choice of a bridge design is that it is an extensive procedure which takes too much time to be done during the planning phase and so mostly the cheapest building price is the decisive factor. For this purpose it is important to know the key factors where you can generally achieve a significant impact on sustainability, considering the whole life cycle and not only the construction phase. To elaborate such indicators, various bridges of the same span and usage with similar boundary conditions are examined. Considering the ecological evaluation of road bridges and street overpasses, the traffic impact is a very important factor. It produces a similar amount of CO 2 emissions as estimated by the LCA (life-cycle assessment) while being subject to higher fluctuations. Therefore, one very important indicator for making a bridge more sustainable is to reduce or partially even avoid traffic jams during construction, maintenance and deconstruction. It was finally found that one of the most important parameters is a correct picture of future scenarios and that one structure should always be considered only as part of an entire construction stage.