The Role of Shrinkage Strains Causing Early-Age Cracking in Cast-in-Place Concrete Bridge Decks

Early-age cracking in cast-in-place reinforced concrete bridge decks is occurring more frequently now than three decades ago and principle factors that lead to early-age deck cracking are not fully understood. A finite element (FE) simulation methodology for assessing the role of shrinkage-induced strains in generating early-age bridge deck cracking is described. The simulations conducted indicate that drying shrinkage appears to be capable of causing transverse (and possibly longitudinal) bridge deck cracks as early as 9 to II days after bridge deck placement. The drying-shrinkage induced stresses would result in transverse cracking over interior pier supports in a typical bridge superstructure considered in the finite element simulations conducted

Heated Bridge Deck System and Materials and Method for Constructing the Same

Aheated bridge deck (20) uses electrodes (24,26) embedded within conductive concrete and connected to a power Source to remove Snow and ice accumulation. A cement-based mixture containing optimal amounts of conductive materials is molded into pre-formed slabs (22) placed atop the paved Surface of a bridge deck. Alternatively, the conductive concrete may be cast in place on top of an existing bridge deck. A control unit with temperature and moisture Sensors may be coupled to the heated bridge deck

Performance of Pyrament Cement Concrete in a Highway Bridge Deck

Pyrament Blended Cement (PBC) is a high performance cement that was developed by Lone Star Industries. Concrete that is made with PBC is rapid setting, has high strength and low permeability. The Kentucky Transportation Cabinet chose to use PBC concrete in a lull·depth bridge deck. The objectives of this study were to evaluate the construction and performance of a full-depth bridge deck constructed of PBC concrete and to compare the data obtained to historical construction and performance properties of conventional, Class AA bridge deck concrete. This report provides information relative to construction activities, materials properties, and a summary of the three-year performance of the experimental bridge deck

Evaluation of the Environmental Impacts of Bridge Deck Runoff

Bridges are located in very close proximity to receiving waters, and regulatory agencies often require specific stormwater control measures for bridge deck runoff. While there is some information available on roadway runoff, few studies have focused on bridge deck runoff. Currently, there is no information available regarding the impacts of bridge deck runoff on receiving waters in Nebraska. Due to the cost, maintenance, and design issues associated with implementing structural controls for bridge deck runoff, it is important to develop a better understanding of the relationship between bridge deck runoff and potential impacts to receiving streams. The objectives of this research were to evaluate the quality of bridge deck runoff; to determine the effects of bridge deck runoff on surface water bodies in Nebraska by evaluating water and sediment chemistry; and to evaluate the effects of bridge deck runoff on aquatic life. The goal was to identify the potential environmental impacts of bridge deck runoff on receiving streams, and to determine design criteria that could be used by NDOR or regulatory agencies to identify when structural controls for bridge deck runoff may be necessary to protect instream water quality and aquatic life. Throughout the course of the project, we conducted in-stream dry weather sampling, sediment sampling, wet weather bridge runoff sampling, and preliminary toxicity testing. Statistical analysis of upstream and downstream in-stream samples showed that bridges did not impact the quality of the water body. Sediment sampling did not show an increase in streambed sediment concentrations from downstream to upstream. The concentrations of bridge runoff samples were higher than literature event mean concentration (EMC) values. This was mainly due to the fact that the summer of 2012 had only two rain events of significant size and there was a large antecedent dry period (ADP) between storms, making the samples much more concentrated. Two runoff events were also used in a 48-hour 5 dilution series toxicity test with fat head minnows, and no negative effects were found. These preliminary results show that there were no apparent effects of bridges on water quality and aquatic life

Evaluation of the Environmental Impacts of Bridge Deck Runoff

Bridges are located in very close proximity to receiving waters, and regulatory agencies often require specific stormwater control measures for bridge deck runoff. While there is some information available on roadway runoff, few studies have focused on bridge deck runoff. Currently, there is no information available regarding the impacts of bridge deck runoff on receiving waters in Nebraska. Due to the cost, maintenance, and design issues associated with implementing structural controls for bridge deck runoff, it is important to develop a better understanding of the relationship between bridge deck runoff and potential impacts to receiving streams. The objectives of this research were to evaluate the quality of bridge deck runoff; to determine the effects of bridge deck runoff on surface water bodies in Nebraska by evaluating water and sediment chemistry; and to evaluate the effects of bridge deck runoff on aquatic life. The goal was to identify the potential environmental impacts of bridge deck runoff on receiving streams, and to determine design criteria that could be used by NDOR or regulatory agencies to identify when structural controls for bridge deck runoff may be necessary to protect instream water quality and aquatic life. Throughout the course of the project, we conducted in-stream dry weather sampling, sediment sampling, wet weather bridge runoff sampling, and preliminary toxicity testing. Statistical analysis of upstream and downstream in-stream samples showed that bridges did not impact the quality of the water body. Sediment sampling did not show an increase in streambed sediment concentrations from downstream to upstream. The concentrations of bridge runoff samples were higher than literature event mean concentration (EMC) values. This was mainly due to the fact that the summer of 2012 had only two rain events of significant size and there was a large antecedent dry period (ADP) between storms, making the samples much more concentrated. Two runoff events were also used in a 48-hour 5 dilution series toxicity test with fat head minnows, and no negative effects were found. These preliminary results show that there were no apparent effects of bridges on water quality and aquatic life

Fiber reinforced polymer (FRP) bridge deck life-cycle cost analysis

A model was developed to compare the life cycle cost (LCC) of fiber reinforced polymer (FRP) bridge decks with steel reinforced concrete (SRC) bridge decks. The objective was to analyze the viability of FRP for certain bridge deck projects.;Current LCC models of FRP bridge decks versus SRC bridge decks consider only manufacturing and erection costs in the cost calculations. They do not consider one of the most important advantages of FRP for construction, which is its light weight. The proposed model includes the cost savings in support structures when FRP is chosen as opposed to SRC, as well as the user costs occurring during bridge installation, maintenance, repair, and disposal processes. A computer program, FRP Bridge Deck LCC Analyzer, was developed for conducting the comparison analysis. The program incorporates the service life estimation of the FRP deck based on the Factor Method. An LCC comparison between FRP bridge deck and SRC bridge deck was developed for a Base Case.;Three case studies of bridges in West Virginia were performed using the program. Sensitivity of certain parameters including FRP manufacturing cost and average daily traffic (ADT) were studied. The results suggest that FRP bridge deck was economically viable to replace concrete bridge decks for Goat Farm, Katy Truss, and La Chein bridge deck projects

Bridge deck assessment using visual inspection, ground penetrating radar, portable seismic property analyzer-ultrasonic surface wave, hammer sounding and chain drag

Integrated non-destructive techniques were utilized to assess the condition of a reinforced concrete bridge deck. There were two main objectives accomplished. The first objective was to assess the integrity of the reinforced concrete bridge deck using four non-destructive techniques, namely visual inspection, ground penetrating radar, portable seismic property analyzer-ultrasonic surface wave, and hammer sounding and chain drag. Visual inspection data were used to identify signs of deterioration on surface of the bridge deck such as cracking, concrete leaching, and reinforcement corrosion. Ground penetrating radar data were used to determine the relative condition of the bridge deck. However, due to the significant differences in depth of the embedded reinforcements, ground penetrating radar data were not useful in terms of assessing the overall condition of the bridge deck. Portable seismic property analyzer-ultrasonic surface wave data were used to determine the concrete quality of the bridge deck by estimating averag Young\u27s modulus (elastic modulus). Hammer sounding and chain drag data were used to identify non-delaminated and severe delaminated areas in the bridge deck. The second objective was to demonstrate the effect of temperature and moisture content changes on ground penetrating radar signal amplitude. Ground penetrating radar signal amplitude variations associated with different weather condition of temperature and moisture changes were evaluated. Ground penetrating radar signal amplitude was increasingly attenuated during low temperature and high moisture content. In contrast, ground penetrating radar signal amplitude was decreasingly attenuated during high temperature low moisture content --Abstract, page iii

A numerical investigation into the aerodynamic characteristics and aeroelastic stability of a footbridge

The results of a numerical investigation into the aerodynamic characteristics and aeroelastic stability of a proposed footbridge across a highway in the north of England are presented. The longer than usual span, along with the unusual nature of the pedestrian barriers, indicated that the deck configuration was likely to be beyond the reliable limits of the British design code BD 49/01. The calculations were performed using the discrete vortex method, DIVEX, developed at the Universities of Glasgow and Strathclyde. DIVEX has been successfully validated on a wide range of problems, including the aeroelastic response of bridge deck sections. In particular, the investigation focussed on the effects of non-standard pedestrian barriers on the structural integrity of the bridge. The proposed deck configuration incorporated a barrier comprised of angled flat plates, and the bridge was found to be unstable at low wind speeds with the plates having a strong turning effect on the flow at the leading edge of the deck. These effects are highlighted in both a static and dynamic analysis of the bridge deck, along with modifications to the design that aim to improve the aeroelastic stability of the deck. Proper orthogonal decomposition (POD) was also used to investigate the unsteady pressure field on the upper surface of the static bridge deck. The results of the flutter investigation and the POD analysis highlight the strong influence of the pedestrian barriers on the overall aerodynamic characteristics and aeroelastic stability of the bridge

Advancement in FRP composites using three-dimensional stitched fabrics and enhancement in FRP bridge deck component properties.

Use of FRP composites in construction industry has been growing rapidly. However, currently all composite products are manufactured with one and/or two dimensional fibers and fabrics (1-D or 2-D). A shortcoming thick composite (\u3e 0.75 in.) made of 1-D or 2-D fabrics is its dramatic reduction in strength, i.e., up to 50% of thin (\u3c0.5 in.) composites. This can be attributed to shear lag leading to ply-by-ply failure; in addition, premature failure of matrix and fibers or the interface failure is very common in thick composites. Therefore, the motivation of the present work is to fabricate and test composites with 3-D stitched fabrics, which overcome the limitations in composites made of 1-D or 2-D fabrics. In this study, composites were fabricated using 3-D stitched fabrics with different: (1) fiber architecture; (2) stitch density; (3) stitch material; and (4) manufacturing process. Strength and stiffness of composites with 3-D stitched fabrics (at coupon level) under tension, bending and shear loads were experimentally established and theoretically evaluated. Structural properties of composites made of 3-D stitched fabrics were compared with the structural properties of composites made of unidirectional fibers and 2-D stitched fabrics. Composites made of 3-D stitched fabrics were found to have enhanced strength and stiffness (about 30%). The existing FRP bridge deck component (first generation) was modified with respect to weight, fiber architecture and manufacturing process leading to the development of the second generation FRP bridge deck component. In the second generation FRP bridge deck component, the self-weight was reduced by about 11% without sacrificing strength and stiffness. The global stiffness of second generation FRP bridge deck component was evaluated experimentally (3 point bending test) and theoretically by Approximate Classical Lamination Theory. The ultimate stress of second generation FRP bridge deck component (30.8 ksi) was three times more than that of first generation FRP bridge deck component (10.3 ksi). The stiffness of second generation FRP bridge deck component was found to be 8.28E+08 lbs-in2/foot width while the stiffness of first generation FRP bridge deck component was found to be 8.44E+08 lbs- in2/foot. Trail second generation FRP bridge deck module has to be tested under fatigue loads