Journal of Bridge Engineering

The structural performance of reinforced concrete bridges gradually deteriorates due to material aging and concrete cracking. Reported here are the experimental investigations and the nonlinear finite-element analysis of two arch ribs removed from a decommissioned bridge and reinstalled in the laboratory. The old bridge had been in service for 28 years. The full-scale static tests for two arch ribs were performed. The load–displacement and load–strain relationships, the residual load-carrying capacity, and the failure form are explored in detail. The structural analysis software Marc is invoked in the theoretical computations. Both geometrical and material nonlinearities are considered. Moreover, the material aging and the structural damage are introduced in the finite-element model. For comparison, the undamaged and geometrically perfect arch rib is analyzed at the same time. A comparison between the experimental and theoretical results is made. It can be concluded that the initial cracks, the reinforcement corrosion, and the variation of the arch axial line shape are the crucial effects for the structural ultimate load-carrying capacity and failure mode.

The live load structural capacity of open-spandrel arch bridge structures is difficult to quantify. In addition to live and dead loads, geometric nonlinear effects, temperature effects, and material behavior play key roles in the design and load rating of such a structure. This paper is a case study that illustrates the effect these variables have on load rating a two-span shallow concrete arch bridge. Presented are load ratings of the structure’s arch ribs using a three-dimensional finite-element model with American Association of State Highway and Transportation Officials publications. As a result of this study, a refined analysis is recommended for load rating arch bridges.

In the nonlinear analysis of a reinforced concrete T-beam bridge superstructure using grillage idealization, and rigid–plastic idealization of moment–curvature and torque–twist relationships of the resulting grillage members, it becomes necessary to compute the plastic rotation capacity of the resulting T-beam bridge girder due to limited ultimate strain capacity of concrete. An idea about the plastic rotation capacity of these members enables one to determine the true ultimate load carrying capacity of this type of structure, extent of redistribution of stresses at failure, and ductility of the structure. This paper presents analytical methods to determine the plastic rotation capacity of reinforced cement concrete T-beam bridge girder (or grillage member) under the combined influence of flexure and torsion. The methods have been validated by experiments. The analytical methods are based on skew-bending and space truss theories. The tests have been carried out on 1:6 microconcrete models. The salient conclusions have been enumerated.

A substantial amount of research has been performed on the use of high performance construction materials and their effects on the anticipated frequency of maintenance and on the time to repair or replacement. Practical implementation of this work has been limited due to the lack of useable methods and information on the life-cycle costs and benefits of alternative approaches in the preliminary design stages of projects, when decisions regarding materials selection are typically made. The lack of simple methods for making quick life-cycle economic comparisons typically results in the use of conventional materials because their impact on performance is well known, even though high-performance materials may actually be more cost effective. This paper identifies the most significant parameters for evaluating the time to corrosion of reinforced concrete structures.

To optimize value, design engineers often need to make decisions on what materials should be used in a reinforced concrete (RC) bridge structure exposed to potentially corrosive environments. Part I of this paper series provided a methodology by which design engineers can easily identify sensitive variables affecting the service life of RC structures exposed to potentially corrosive environments. However, a material that significantly improves the resistance to corrosion may not add real value if the cost of the material is too high. The costs of materials that extend the service-life are not well established during the design process and designers are often in a quandary on how to select materials that optimize project value. Instead of estimating the costs of these durable materials that enhance the service life, this paper provides a methodology that examines the inverse question: How much more could a RC structure constructed with durable material cost, relative to the cost of the same structure constructed with conventional materials, and still be more economical?

A prestressed concrete (PC) box-girder bridge was instrumented to enable monitoring of its surface and body temperature. The daily variations of temperature in the pavement and upper beam of the bridge were greater the deeper from the surface. During daytime on a fine day, bridge surface temperatures were higher than air temperatures, and at nighttime on a fine night, temperatures at the surface were lower than air temperatures. It is well known that sensible heat transfers depend on wind speed and surface temperature. The wind speed measured at the bridge and on the road revealed that the wind speed at the bridge was higher than at the road due to their topography. This wind effect during the daytime causes the surface temperature at the bridge to be lower than that at the road. Thus, the reason why only bridge surfaces may freeze while roads do not can be explained by the fact that the surface temperatures of bridges are usually lower than those of roads, which can be attributed to their energy budget patterns caused by the wind speed differences between bridges and roads.

This paper presents findings of field tests and analysis of two conventionally reinforced concrete (CRC) deck girder bridges designed in the 1950s. The bridges are in-service and exhibit diagonal cracks. Stirrup strains in the bridge girders at high shear regions were used to estimate distribution factors for shear. Impact factors based on the field tests are reported. Comparison of field measured responses with AASHTO factors was performed. Three-dimensional elastic finite-element analysis was employed to model the tested bridges and determine distribution factors specifically for shear. Eight-node shell elements were used to model the decks, diaphragms, bent caps, and girders. Beam elements were used to model columns under the bent caps. The analytically predicted distribution factors were compared with the field test data. Finally, the bridge finite-element models were employed to compare load distribution factors for shear computed using procedures in the AASHTO LRFD and Standard Specifications.

Integral abutment bridges are often a preferred bridge type for moderate spans throughout the United States. However, design methods and construction details vary from state to state. Variations between states are noted in the methods employed to accommodate deformations in the piles. The significance of these differences was evaluated through a finite-element study. The effects of backfill properties and soil restraint on piles were evaluated with regard to bridge distortions and maximum moment realized in the piles. Results show that bridge expansion is predominantly affected by backfill conditions, whereas contraction is influenced by pile restraint conditions. Pile moments are minimized when denser backfill and lower pile restraint are provided. The influence of abutment soil-structure spring modeling assumptions is addressed. Models were calibrated to the reference bridge at Orange-Wendell, Mass, which has been instrumented and data collected for 4 years.

This paper presents a time-dependent finite-element analysis of a two I-girder composite bridge with a concrete slab. The creep and shrinkage of the concrete slab are considered as sources of time-dependent behavior. This analysis, unlike others, includes the shear-lag effect of the concrete slab on the time-dependent behavior of two I-girder bridges. An example calculation is given for a two-span continuous composite bridge with a cracking region in the concrete deck near the interior support. It is shown that the shear-lag effect becomes significant at the edge of the cracking region and at the bridge ends.

The results from a parametric study on the impact factors for 180 curved continuous composite multiple-box girder bridges are presented. Expressions for the impact factors for tangential flexural stresses, deflection, shear forces and reactions are deduced for AASHTO truck loading. The finite-element method was utilized to model the bridges as three-dimensional structures. The vehicle axle used in the analysis was simulated as a pair of concentrated forces moving along the concrete deck in a circumferential path with a constant speed. The effects of bridge configurations, loading positions, and vehicle speed on the impact factors were examined. Bridge configurations included span length, span-to-radius of curvature ratio, number of lanes, and number of boxes. The effect of the mass of the vehicle on the dynamic response of the bridges is also investigated. The data generated from the parametric study and the deduced expressions for the impact factors would enable bridge engineers to design curved continuous composite multiple-box girder bridges more reliably and economically.

This paper evaluates the behavior and performance of laminated circular elastomeric bearings and compares them to those of square and rectangular bearings. The study included an experimental evaluation and a nationwide survey of state Department of Transportations on the use and performance of circular bearings and bearings in general in their states. The experimental investigation studied the bearings' behavior in compression, compression and rotation, and compression and shear. Results from this limited study showed that the three bearings have similar stress-strain behavior in compression and they are in agreement with the AASHTO LRFD guide stress–strain curves. In compression and rotation, the AASHTO LRFD substructure moments are slightly less than the measured values for circular bearings and rectangular bearings rotated about their strong axis for a compressive stress of $10.3\mathrm{MPa}$ $\left(1.5\mathrm{ksi}\right)$ and slightly higher than those of rectangular bearings rotated about their weak axis. In compression and shear, the shear stiffness of circular and square bearings is in agreement with theoretical values within the range of design displacements. Results from the survey showed that many states are using circular bearings and more states would consider using them, however no maintenance or monitoring data were available on their short-term and long-term performance.

Twenty-nine specimens were tested to investigate the fatigue resistance of high-performance steel (HPS-485W) $\left(70\mathrm{W}\right)$ continuous plate with punched holes. Specimen thickness, hole diameter, and method used for creating the holes were varied to examine their effect upon fatigue resistance of punched connections utilizing high performance steel. Eight of the 29 specimens were drilled or subpunched and reamed specimens, all of which rated as Category B details. The remaining 21 specimens had punched holes and rated considerably below a Category B. Results from this investigation suggest that current restrictions mandated by some state DOTs concerning punching holes are not overly restrictive when HPS-485W $\left(70\mathrm{W}\right)$ is utilized. Performance of drilled and subpunched and reamed specimens met (or exceeded) 2004 AASHTO requirements for Category B details.

This paper traces the international evolution of mathematical theory and construction processes that affected the design, construction, and use of continuous truss bridges in the United States. It covers the evolution from intuitive designs in wood and iron of the early 19th century to the mathematically rigorous designs of long-span continuous steel trusses in the late 19th and early 20th centuries.

Lenticular-shaped iron truss bridges, built exclusively by the Berlin Bridge Company of East Berlin, Conn., dominated the New England and adjacent area’s modest span bridge market for over a decade at the end of the nineteenth century. This paper examines this phenomenon in the larger context of earlier European development of the lenticular form and, with the assistance of numerous patent drawings and photographs of American lenticular bridges that were either proposed or built prior to the 1883 formation of the Berlin Bridge Company.

It has been argued that the AASHTO LRFD design code for maximum live loads on highway bridges is overly conservative. In an attempt to determine the level of conservativeness, if any, the writers developed a methodology incorporating real-time visual data collection from traffic cameras coupled with structural strain response of girder bridges. Average daily truck traffic along with frequency of multiple presences (same lane as well as adjacent lanes) and lane-wise truck traffic distribution were estimated for a steel-girder highway bridge on I-95 in Delaware. These data compared well with predictions from a Poisson process based model developed for this study. Statistical properties of girder moments in single and multiple presence conditions were determined as well. In this particular example, the girder design moment on the $24.6\text{foot}$ approach span according to AASHTO specifications was found to be about 3.5 times higher than that estimated from the in-service data.