Bridge Structures - Volume 12, issue 3-4

Authors: Mahmoud, Khaled M.

Article Type: Editorial

DOI: 10.3233/BRS-170108

Citation: Bridge Structures, vol. 12, no. 3-4, pp. 53-53, 2017

Authors: Battista, M. | Arafa, M. | Najm, H. | Parvardeh, H. | Jin, P. | Vasconez, R.

Article Type: Research Article

Abstract: Long-term bridge performance data available in the NBI database was used to identify statistical trends between several qualitative and quantitative performance criteria that correlate to higher or lower prevalences of structural deficiency in US bridges. An internet-based resource which compiles and inventories all bridge inspection data for all bridges, nationwide into a single, interfaced LTBP database “Bridge Portal”. The approach is to extract data on bridge material, climate, span length, average daily traffic volume, and ownership for structurally deficient bridges and to compare and correlate the sampled data from the total bridge population nationwide. A method is designed to process …this data through several normalization and adjustment filters that correct for sample size and account for structural age, which is the final parameter. The advantage of this approach is that it separates deficiency from basic structural and material assumptions and includes other relevant factors that might not otherwise have been considered or previously explored in such detail. Analysis results and implications of these results to the present and future conditions of the United States’ bridge infrastructure network are presented. Show more

Keywords: Structural deficiency, Long-term bridge performance, National Bridge Inventory, bridge performance database

DOI: 10.3233/BRS-160104

Citation: Bridge Structures, vol. 12, no. 3-4, pp. 55-72, 2017

Authors: ElHattab, Ahmed | Uddin, Nasim | OBrien, Eugene

Article Type: Research Article

Abstract: Bridge structures are subject to continuous degradation, which requires an ongoing screening to give an early warning if the bridge becomes unsafe. In recent years, many authors have investigated a shift of the instrumentation from the bridge to a passing vehicle to collect indirect measurements for the bridge responses. This approach is known by ‘drive-by’ bridge inspection. This paper introduces a new method in the drive-by bridge inspection concept which employs acceleration measurements of a non-specialized vehicle to identify the change in the bridge responses due to structural damage. Two damage indices are included in the study, the vehicle acceleration …spectra and the change in the bridge displacement. The paper will use an explicit approach for solving the Vehicle-Bridge Interaction (VBI) problem to give a more accurate representation of the truck/bridge interaction. The VBI problem will be solved using LS-Dyna Finite Element Analysis (FEA) program. The bridge is represented by discretized one-dimensional (1D) FE beam elements, and by discretized two-dimensional (2D) plate bending elements. Damage is defined in this study as a change in the damping ratio and/or gradual decrease in structure stiffness. Two vehicle models are used in the study, the two-degree-of-freedom quarter car model and the four-degree-of-freedom half car model. Both smooth and rough profiles are considered in the study. Show more

Keywords: Bridge, drive-by, indirect, monitoring, SHM, health monitoring, vehicle

DOI: 10.3233/BRS-170106

Citation: Bridge Structures, vol. 12, no. 3-4, pp. 73-84, 2017

Authors: Fawaz, Ghassan | Waked, Michel | Mabsout, Mounir | Tarhini, Kassim

Article Type: Research Article

Abstract: This paper presents the results of a parametric study investigating the influence of railings on the load carrying capacity of simply-supported, one-span, multi-lane reinforced concrete slab bridges. A total of 112 bridge cases were modeled using finite element analysis (FEA) subject to AASHTO HS20 truck loadings positioned transversely and longitudinally to produce the maximum bending moments and deflections for cases with and without railings which were compared with AASHTO procedures. Placing two railings on the bridge, AASHTO Standard Specifications procedures overestimated the FEA moments by 100% for one-lane bridges, and by 20% for bridges with two or more lanes. AASHTO …LRFD overestimated the FEA moments in all bridge cases by 150% for one-lane, 70% for two-lanes, and a 30% for three- and four-lanes when placing two railings on slab bridges. The results of this study support the AASHTO procedures in designing new concrete slab bridges. However, the paper can also assist engineers in modeling the actual bridge geometry using FEA to account for structural elements such as integral railings in resisting special permit loading on concrete slab bridges. Show more

Keywords: Concrete slab bridges, railings, multilane bridges, finite element analysis, AASHTO specifications

DOI: 10.3233/BRS-170107

Citation: Bridge Structures, vol. 12, no. 3-4, pp. 85-96, 2017

Authors: Abu Dabous, Saleh

Article Type: Research Article

Abstract: Reliable deterioration models for forecasting the condition of bridge elements, systems, and networks are essential components of any bridge management system. Estimating deterioration transition probabilities is the basis of the popular Markov chain deterioration model. Transition probabilities have been produced in the literature by statistical and probabilistic analysis performed on available bridge inspection and condition data. The available data may be limited or inconsistent with the Markov chain transition period. In addition, the conventional probability theory has limitations when applied to problems with a stochastic nature such as bridge deterioration. This paper introduces a novel method based on the theory …of evidence for bridge deterioration modeling through expert judgment elicitation. The advantages of the theory of evidence over the traditional probability theory are discussed and the process for the theory implementation is demonstrated with a case study to validate the application of Dempster–Shafer theory of evidence to estimate the transition probabilities. Based on the results, the theory of evidence is proposed as a scientific expert judgement elicitation technique in the area of bridge condition rating and deterioration modeling. Expert judgment elicitation and theory of evidence application hold potential in the field of bridge management and require further investigation and research. Show more

Keywords: Bridge deterioration, transition probability, markov chains, Dempster–Shafer, theory of evidence

DOI: 10.3233/BRS-170105

Citation: Bridge Structures, vol. 12, no. 3-4, pp. 97-106, 2017

Article Type: Other

Citation: Bridge Structures, vol. 12, no. 3-4, pp. 107-107, 2017

Article Type: Other

Citation: Bridge Structures, vol. 12, no. 3-4, pp. 109-109, 2017