Journal of Bridge Engineering

Inspections are important to ensuring adequate safety and performance of a bridge throughout its service life. Bridge inspections are highly connected with maintenance decisions and can help in managing maintenance activities while maintaining a reliable bridge network. Routine inspections are the most common type of highway bridge inspections in the United States. The National Bridge Inspection Standards (NBIS) requires that, for almost all bridges, a routine inspection should be conducted at least every 24 months. However, limitations of current bridge inspection practices impact the quality of information provided about bridge conditions and the subsequent decisions made based on that information. Much research in the field of bridge inspection planning has been conducted to assist bridge inspectors in the inspection planning process and improving routine inspections. Accordingly, the goal of this study is to provide an overview on current bridge inspection practices in the United States and conduct a systematic literature review on innovations in the field bridge inspections planning while investigating research gaps and future needs. This paper provides a background on the history of bridge inspection in the United States, including current bridge inspection practices and their limitations and analyzes the connections between nondestructive evaluation techniques, deterioration models, and bridge inspection management. The primary emphasis of the paper is a thorough analysis of research proposing and investigating different methodologies for inspection planning and scheduling. Studies were analyzed and categorized into three main types of inspection planning approaches, based on: reliability, risk-analysis, and optimization approaches. The study revealed gaps and limitations in the current proposed techniques for inspection planning. The findings of this review will help in characterizing the current state of bridge inspection programs and future research needs to enhance inspection programs and reduce the gap between inspection practice and research.

Recent findings reported in the contemporary literature have underlined the criticality of including climate change effects in models of deterioration of civil engineering structures. Highway bridges, when exposed to unfavorable environmental conditions and climate change settings and when simultaneously situated in moderately to highly active seismic zones, may experience reduced structural performance during earthquake events. For bridges in such regions, past studies have revealed the criticality of considering deterioration when computing seismic losses, which may constitute a significant percentage of the life-cycle cost planning for the structure. In acknowledging the potential effects of climate change on bridge deterioration and seismic fragility, a renewed systematic assessment of seismic life-cycle cost then becomes necessary for informed decision making and economic investment. Addressing this critical need, we propose a novel framework for evaluating the lifetime seismic losses of highway bridges that considers earthquake hazards, aging effects, and global warming due to climate change. The proposed framework was first demonstrated on two structurally distinct case-study bridges––multispan continuous (MSC) steel and MSC concrete-girder bridges located in the southeastern United States. Both bridge types comprise multiple seismically vulnerable bridge components that are also prone to the adverse effects of environmental degradation. It was found that there was a substantial underprediction in the lifetime seismic loss––by 6.7% for the MSC steel bridge and 13.2% for the MSC concrete bridge––when expected future climate change was neglected. Additionally, the proposed framework was applied to a seismically designed MSC concrete-girder bridge in order to evaluate the influence of seismic design practices on the lifetime seismic losses of aging highway bridges, including climate change effects.

Long-span bridges are part of a vital road infrastructure for communities living in the coastal regions of Norway. New projects considering advanced bridge concepts will contribute to solidifying this dependency. These are locations that are increasingly exposed to extreme weather and authorities have concerns about vehicle safety. The traffic safety problem can have implications for new designs, as well as for the management and possible retrofitting of existing bridges. This work provides insights into the maturity of computational models and simulation procedures and the readiness of technological concepts to mitigate accident risk, as well as gaps in the relevant research domain. This is achieved by a systematic literature search, mapping, and metadata analysis. It is found that the major area for development in current models is the ability to credibly predict a vehicle’s operating wind environment on bridges and the resulting aerodynamic loads on the vehicle. Another identified gap is the critical lack of real-world observations and experience. Little evidence of knowledge transfer from domains outside of civil engineering is found, despite this being a complex multidisciplinary problem. The technological readiness of solutions explored in current research is found to be low, with no evidence of any studies going beyond the proof-of-concept stage.

This paper investigates the structural performance and soil–culvert interaction of large-span precast concrete three-sided culverts (TSCs). Three TSCs with flat top slabs have been instrumented with 30 pressure cells and 56 strain gauge vibrating wire sensors. The test culverts cover a range of spans from 7.3 to 13.5 m, each under a different installation condition. The instrumentation plans were established based on the results of three-dimensional finite-element analyses. This paper makes a contribution to (1) recommendations on the design of instrumentation plan and sensors selection criteria; (2) details of the instrumentation installation procedure and corresponding modifications to accommodate specific conditions of each culvert; and (3) field measurements and analysis of the data from a culvert covered with 3.2 m of backfill soil. Useful guidelines are provided for instrumenting similar structures. The field data were used to evaluate the current design practice and evaluate the Canadian Highway Bridge Design Code (CSA 2014) provision regarding earth loads on TSCs. The obtained data reveal the nonuniform distribution of the earth pressures on the top slab with an average vertical arching factor of 1.05. Also, the strain gauge measurements indicate the development of bending moment at the base of the sidewall, which was attributed to the rotation of the strip footing predicted from the developed preliminary numerical analysis.

High-performance concretes without steam curing have great potential to improve crack resistance in the hogging-moment regions of continuous steel–concrete composite beams. This paper conducts experiments to investigate the cracking resistance of hogging-moment regions of prefabricated composite beams consisting of steel–NSCs (normal-strength concretes), natural curing steel–UHPCs (ultrahigh performance concretes), or steel–UHTCCs (ultrahigh toughness cementitious composites). The tensile strengths of natural curing UHPCs and UHTCCs are first measured because the concretes are usually in the tensile state in hogging-moment regions. Flexural tests are then conducted to investigate several important parameters of steel–NSC/–UHPC/–UHTCC composite beams: deflections, initial cracking loads, crack propagation, interlayer slips, and flexural bearing capacity. It is demonstrated that relative to traditional composite beams, steel–UHPC composite beams without steam curing can effectively improve the hogging-moment bending performance such as increasing cracking load, reducing interfacial slips, and concrete slab crack width. Moreover, it is found that although the steel–UHTCC composite beams are not as good as the steel–UHPC composite beams in terms of initial cracking loads but have better performance in controlling crack widths and lengths. The effect of prestressing on steel–UHPC composite beams under hogging moment is also studied and demonstrated to be influential in further increasing the cracking performance in hogging-moment regions.

A new method for building seismically resilient bridges is investigated using Accelerated Bridge Construction (ABC) technologies. A hybrid two-column bridge bent with posttensioned precast concrete columns and a diagonal buckling restrained brace (BRB) as an external energy dissipation device was tested under cyclic loads. The design of the initial posttensioning force and selection of BRB tensile yield strength is presented. The connection design at the footing and cap beam of the diagonal BRB considering column-free rocking is described. The experimental performance of the bridge bent subjected to cyclic loads is discussed. The performance of the bridge bent was enhanced in terms of hysteretic energy dissipation until fracture of the BRB steel core at a 5.0% drift ratio. The two unbonded posttensioned (PT) bars of one column yielded shortly after fracture of the BRB steel core. The columns of the hybrid bridge bent underwent rocking and remained undamaged up to a 6.0% drift ratio, at which point the longitudinal mild steel column bars yielded. The gusset assemblies at the cap beam and footing remained elastic throughout the test. The BRB could be replaced after an earthquake, and the proposed system is promising for constructing resilient bridges using ABC technologies in seismic regions.

This paper reports on double shear push-out tests conducted on steel-to-ultra-high-performance concrete (UHPC) connections based on studs of 30- or 22-mm diameter in slabs of 35, 55, or 150 mm thickness. The results show that with an increase in stud diameter, the longitudinal shear strength has improved by 25% and 94% for ultra-short and long studs (of aspect ratios below and equal to 4.0), respectively. For short studs, both the aspect ratio and concrete cover greatly influenced failure by partial stud fracture or UHPC pryout, while the diameter governed failure behavior for long studs. Decreases in aspect ratio and cover thickness caused shear resistance to drop by 40% and 7%, respectively, for 30- and 22-mm diameter studs. Regression analyses show that the shear strength, slip stiffness, and ductility of the connections are exponential, sinusoidal, and polynomial functions, respectively, of the stud aspect ratio. The ultra-short stud–UHPC connections are 62% stiffer in slip than their normal concrete counterparts. Future work should entail fatigue testing of the connections.

Horizontal web cracks are frequently observed at the ends of pretensioned concrete members (I girders or Bulb Tee girders) at the time of prestress transfer. Using a modified Gergely–Sozen (mG-S) model to calculate the spalling forces of prestressed concrete girder ends was illustrated step by step. A new design procedure based on the mG-S model was proposed with the aim to control horizontal web cracks by debonding a number of strands. Three different criteria were introduced to determine the suitable debonding ratios and debonding patterns of the girder ends. Prestressed Standard Wisconsin Wide-Flange girders (WF54) and Standard Nebraska I girders (NU1100) were chosen for case studies, in which several debonding ratios and debonding patterns were analyzed to check the reasonability and effectiveness of the current limits in the standards. The analysis results obtained from the mG-S model were validated by the finite-element analysis (FEA) method, which proved that 25% debonding can greatly reduce the concrete tension strains in the web but cannot eliminate the web crack, and it can satisfy the code requirements on the vertical reinforcement stresses and crack width. Four percent of the total prestressing force is enough to be used to design the vertical reinforcement at the girder ends. The recommendations on debonding patterns are also presented.

Four short shear-critical rectangular columns were constructed and tested under monotonic shear loading and a constant compressive axial load. The main variable in these tests was the amount of shear reinforcement. The objectives were to examine the behavior of columns with small shear span-to-depth ratios and develop a method for predicting the shear strength of such columns. An inclined compressive strut was found to form between the column ends and contribute to the column shear capacity. The observed column responses were compared with predictions made using sectional analyses, combined strut and compression field models, and nonlinear finite-element analyses. Failure shears predicted by the sectional analyses were conservative. The proposed model, which considers the contribution of strut action gave reasonable estimates of the shear strength with V_exp/V_pred varying from 0.93 to 1.00. Nonlinear finite-element analysis gave accurate predictions of shear strength, as well as predictions of the complete behavior of the columns. It was determined that the strut effect is significant for reinforced axially loaded columns with shear span-to-depth ratios of less than about 2.5 but should not be considered if the columns undergo large deflections.

This paper includes the structural condition assessment of a 164-m suspension bridge in accordance with numerical and experimental methods. A finite-element model was developed using SAP2000 software so that the assessment of the bridge could be calculated numerically. The operational modal analysis method was also used to obtain experimental dynamic characteristics. In this context: (i) numerical dynamic characteristics of the bridge were obtained and compared with the experimental dynamic characteristics, (ii) a model updating procedure was carried out to minimize the differences between the numerical and experimental natural frequencies, (iii) static and dynamic analyses of the bridge were carried out by using the initial and updated finite-element models, (iv) fatigue life assessment of the bridge was investigated, and (v) the utility of the bridge for pedestrians and vehicles was checked according to various regulations. The results showed that updating the finite-element model had a significant role to play in the static and dynamic behavior of the bridge. The results also demonstrated that the bridge was designed to be extremely safe against static, dynamic, and fatigue loads. Finally, it was concluded that the bridge investigated behaves as a girder bridge rather than a suspension bridge.