Accelerated Bridge Construction Research Articles

Analytical Pushover Method and Hysteretic Modeling of Precast Segmental Bridge Piers with High-Strength Bars Based on Cyclic Loading Test

AbstractCompared to cast-in-place bridge piers, precast piers can accelerate bridge construction, but their use in seismic systems is challenging. High-strength bars (≥500 MPa) incorporated with p...

Friction Coefficients for Slide-In Bridge Construction Using PTFE and Steel Sliding Bearings

Slide-in bridge construction (SIBC) has been used in accelerated bridge construction (ABC) for the last decade. Slide-in bridge construction is carried out using bearing pads consisting of polytetrafluoroethylene (PTFE) and steel sliding surfaces. In this study, coefficient of friction (COF) measurements were made with variable surface roughness, lubrication type, sliding speed, and contact pressure. Among three tested surfaces, the rough rolled stainless steel and the carbon steel produced COF values much higher than those of stainless steel with a #2B surface. Unlubricated and graphite-lubricated surfaces resulted in very high friction values, whereas the values for soap, grease, and oil were comparably lower. The oil and grease tests gave the lowest friction values, 0.90–4.04% and 0.67–5.15%, for the studied contact pressures, respectively, and are recommended for future use. Higher contact pressures typically resulted in lower COF values. Overall, the currently recommended COF values underpredict the COF compared with the results from this study. However, for higher contact pressures, this study found lower COF (e.g., for high pressure of 55 MPa, 2% versus 0.9–1.44%) compared with current recommendations and the opposite for low contact pressures (e.g., for 11 MPa, 2.71% versus 4.04–5.66%). Unlubricated sliding surfaces are not recommended due to the large scatter in comparable data in this study and the literature.

Enhancing Resiliency and Delivery of Bridge Elements using Ultra-High Performance Concrete as Formwork

A feasibility study of the use of ultra-high performance concrete (UHPC) shell as a formwork is presented. The core concept of the research, developed by the first author, is prefabrication of UHPC shell which acts as a stay-in-place formwork. In the proposed approach, after transporting the UHPC shell to site, the construction of structural elements is completed by placing reinforcing cage inside the UHPC shell and post-pouring with normal concrete. The superior properties of UHPC provide excellent means to enhance the service life of bridge elements, while eliminating the need for assembling or stripping of formwork. As a proof of concept, a combination of experimental and numerical studies was conducted, results of which are reported here. Before conducting experimental work, numerical study in the form of finite element analysis was carried out to investigate performance of shell during placement of the normal concrete. To provide a baseline comparison between UHPC shell formwork and conventional methods, two test specimens were constructed and tested under three-point load setup. The shell test specimen demonstrated flexural strength, 14% greater than an equivalent normal strength concrete specimen. The UHPC shell test specimen failure occurred by debonding of shell at the interface and development of a large crack in the shell. The shell test specimen exhibited improved levels of ductility before failure. The preliminary analysis demonstrated that the idea is feasible and useful for accelerated bridge construction applications.

A hysteretic model for self-centering precast concrete piers with varying shear-slip between segments

Self-centering, precast, post-tensioned concrete, bridge columns can provide low-damage under earthquake loading and accelerated bridge construction. These columns can also be designed so that shear-slip occurs between precast segments to provide energy dissipation. This paper, first, presents experimental results of large-scale testing of pier specimens that can self-center and undergo shear-slip under cyclic lateral loading. In these tests, segment interface properties, which control shear-slip, changed as the silicone layer placed between each segment degraded during testing. Specimens with fresh silicone had more energy dissipation, lower stiffness, and higher residual displacements compared with the ones with degraded silicone.A hysteretic model is created to predict the global load-displacement behavior of piers under lateral loading by superimposing self-centering and shear-slip responses. Shear-slip measurements under both quasi-static and rapid cyclic tests were used to characterize the interface frictional properties to be used in hysteretic modeling. Friction coefficients of segment interfaces were also investigated under varying accumulative displacement, normal force, and shear-slip velocity. The proposed hysteretic model is validated using the experimental results.A parametric study was performed using the established hysteretic model to investigate the influence of friction properties of interface materials and initial post-tension forces on the seismic response. The results show that interface materials with lower friction coefficient will lead to enhanced energy dissipation, lower stiffness, and smaller self-centering capability. Selecting lower initial post-tension force decreases the stiffness. Finally, incorporating the hysteretic model in the Capacity-Demand-Diagram method, seismic response of piers with varying properties was predicted. The increase in friction coefficient and initial post-tension force consistently increases the maximum base shear demand. Increasing initial post-tension force decreases the peak displacement in most cases. Increasing friction coefficient can either increase or decrease the peak displacement.

Hysteretic behavior investigation of self-centering double-column rocking piers for seismic resilience

Seismic resilient structures with low structural damage and self-centering behavior after an earthquake are focus issues of current earthquake engineering. Unbonded pretensioned rocking columns offer advantages for accelerated bridge construction in seismic regions, which utilize column-uplifting mechanisms, high strength post-tensioning, and replaceable energy dissipation devices to enhance seismic performance and resilience. The experiment of three 1:3 scale unbonded, post-tensioned rocking bridge bents with different types of external replaceable energy dissipation devices subjected to quasi-static loading protocols, were carried out according to practical engineering demand in high-intensity earthquake regions. An improved analytical model was proposed for predicting the force-displacement relationship of the post-tensioned rocking bridge bent systems considering the neutral axis depth. Minimal physical damage was observed for the post-tensioned rocking bridge bent systems, which exhibit good energy dissipation and self-centering behavior. Especially, the external replaceable buckling-restrained plates dissipaters can be easily replaced if severely damaged subjected to higher than expected ground motions. The satisfactory analytical and experimental comparisons are presented as a validation of the reliability for the high-performance seismic-resistant bridge bent systems and the modelling techniques in this study.

Emulative seismic resistant technology for Accelerated Bridge Construction

Accelerated Bridge Construction (ABC) offers advantages such as rapid construction, limited traffic disruption, fast project delivery, cost savings for the formwork, more accuracy in construction due to prefabrication, better quality control, higher durability, reduced weight of the bridge structure, enhanced safety, and less environmental impacts. ABC has been successfully deployed in low seismic regions. However, given the uncertainty about the adequate performance of connections between precast elements, application of ABC in high seismic regions has been limited. The research investigates the use of two types of emulative connections in a precast bent. The column-to-footing connection consists of member socket, while the column-to-cap beam connection is grouted ducts. These connections intend to emulate the traditional formation of plastic hinges in the bridge columns during an earthquake. A half-scale specimens with emulative connections was tested under quasi-static cyclic loading. Experimental results showed adequate seismic performance of the specimen compared to cast-in-place construction.

Acoustic Emission Sensing for Crack Monitoring in Prefabricated and Prestressed Reinforced Concrete Bridge Girders

Prefabricated and prestressed beams are integral to accelerated bridge construction (ABC) and other construction projects, but concerns exist regarding the development of cracks during curing, form removal, detensioning, transport, installation, and operation. Acoustic emission (AE) sensing techniques have the potential for detecting and locating cracking in prefabricated, prestressed concrete girders used as prefabricated bridge elements and systems (PBES) in ABC as part of a quality assurance/quality control (QA/QC) program. AE measures the elastic waves produced by crack nucleation and growth with an array of point sensors. The AE instrument system is relatively portable, which can allow for it to be an option for off-site fabrication QA/QC and on-site field QA/QC. This paper presents AE measurements and analysis on relatively small laboratory reinforced concrete beam specimens under pullout and three-point bending to demonstrate the efficacy of AE in detecting cracks. It then presents application of AE during detensioning and lifting of full-scale Northeast Extreme Tee (NEXT) beams and Bulb Tee. The results indicate that AE sensing is a practical QA/QC process for PBES elements.

Testing and evaluation of full scale fiber-reinforced polymer bridge deck panels incorporating a polyurethane foam core

A fiber-reinforced polymer (FRP) bridge deck panel that incorporates a polyurethane foam core was developed for accelerated bridge construction and repair. This low cost panel was tested under monotonic loading and compared to applicable FRP design equations. This new prototype system consisted of two stiff facesheets of stitch bonded plain-weave woven E-glass fabric with sloping webs of E-glass woven fabric that are separated by trapezoidal-shaped, low-density polyurethane foam. The polyurethane foam was used in an attempt to reduce initial costs. The panels used in this study were manufactured using a one-step, vacuum-assisted, resin transfer molding process (VARTM) using a newly formulated, two-part, thermoset, polyurethane resin developed by Bayer MaterialScience to facilitate the infusion process. The results of the flexural and shear testing indicated that the prototype panels significantly exceeded the AASHTO Design Code Strength requirements by nearly three times. Even more importantly, the panels behaved linearly-elastically throughout the full range of loading and possessed significant post-buckling strength. In addition, the results of these full-scale panels were used to evaluate the applicability of existing FRP design equations when used for the design of the VARTM- manufactured, prototype FRP bridge deck. Results showed that the existing FRP design equations correctly predicted a flexural failure due to local buckling of the compression flange and a bearing failure due local buckling of the webs beneath the concentrated load.

Study of Bridge Demolition DOT Survey and Available Standard Specifications

There are many damaged bridges in the United States which are either structurally deficient or functionally obsolete and require replacement or rehabilitation, many using accelerated bridge construction (ABC) techniques. Before a bridge is replaced or rehabilitated, the old structure or component needs to first be demolished. Although the AASHTO LRFD Bridge Design Specification presents minimum bridge design requirements, there is limited information about bridge demolition available for designers and contractors in this field. More study is required to determine best practices in demolition administration and avoid further unintentional events. This study presents the results from a survey prepared and disseminated through a research effort under the Accelerated Bridge Construction University Transportation Center (ABC‐UTC). This survey was sent out to all State Departments of Transportation (DOTs). The results of the survey reveal the need for additional guidance in bridge demolition administrations at a national level. According to the results of this study, contractors are the most important part of bridge demolition projects from injuries, fatalities, and responsibility point of view.

Application of Novel Recovery Techniques to Enhance the Resilience of Transportation Networks

Resilience is an important characteristic of the transportation system. It reflects the network’s ability to mitigate shocks, provide alternatives, and rapidly recover to a target performance level. Earthquakes can cause the transportation network to experience severe disruptions that significantly reduce network resilience. To prevent long-term closures after earthquakes, the development of innovative approaches for their rapid restoration is necessary. This paper uses the recent developments in accelerated bridge construction (ABC) techniques as a means to enhance the rapid recovery of the system. ABC techniques often come with increased initial construction costs. In most cases, the additional cost is offset by the improvement of the network performance. To examine the efficiency of ABC techniques on the rapid recovery and on the network performance after earthquakes, the direct and indirect costs during the entire recovery period were analyzed and the relationship between network recovery time and network performance was estimated under different construction techniques. Additionally, the effect of using the incentive method to reduce the repair time was studied. The results show that the use of ABC techniques and the incentive method have great potential to minimize the transportation network’s indirect losses, improve network performance, increase the network’s resilience by decreasing recovery time, and justify the additional initial costs associated with these techniques.

Recommendations for Design of Concentrically Pretensioned, Precast Concrete Bent Caps

Precast, prestressed bent caps are an attractive design option because they permit accelerated bridge construction and can extend the service life of bridges by reducing or eliminating the service-level cracking observed in RC bent caps. A design procedure is recommended for the flexural design of pretensioned bent caps in which the amount of prestressing is selected to ensure zero tension at service, with service- and strength-limit states serving as checks on the design. Recommendations include how to account for openings for connections that may influence the bent cap performance. Using the recommended flexural design procedure and AASHTO shear design provisions, pretensioned bent caps were designed for a suite of multicolumn bridges. The flexural design procedure is shown to be efficient for the design of most bridges, and many bent caps are expected to have only minor cracking, if any, at ultimate demands. The minimum area of transverse reinforcement was found to govern most bridge designs, leading to recommendations to use the general, noniterative sectional shear design method. The resulting designs lead to recommendations for how designers and contractors can use precast, pretensioned bent caps not only to enable accelerated construction and extend bridge service life but also to increase design and construction efficiency.

Experimental and numerical study on an innovative sandwich system utilizing UPFRC in bridge applications

Accelerated Bridge Construction (ABC), a newly embraced construction philosophy, is a paradigm shift in bridge delivery method that includes planning, design, construction, and maintenance. Ultra High-Performance Fiber Reinforced Concrete (UHPFRC), offering superior properties such as exceptional high strength and durability, can be a smart material choice for ABC projects. Steel-Concrete-Steel Sandwich (SCSS) system using UHPFRC has the potential to merge the advanced structural performance with construction efficiency as aimed at the ABC approach.In this research, the implementation of the steel-concrete sandwich system using UHPFRC was investigated by conducting experimental and numerical studies to evaluate the behavior of the innovative proposed system called “Steel-UHPFRC Sandwich.” The system consists of two thin stainless-steel plates folded to form a girder without a top flange.Feasibility study on the proposed system proves that it can both facilitate and accelerate the construction process and have incredibly ductile behavior. The experimental data was also employed to validate the numerical model of the system. Simultaneously, a series of numerical models were conducted to assess the effects of the various parameters on the behavior of the proposed system.

Multi-Criteria Evaluation Framework in Selection of Accelerated Bridge Construction (ABC) Method

Accelerated Bridge Construction (ABC) is bridge construction that uses innovative planning, design and construction methods in a safe and cost-effective manner, which reduces construction mobility and environmental impacts, and contributes to city sustainable planning and development. To deal with the pressing need to support the decisions associated with the selection between the ABC and conventional bridge construction, this paper presents the development of a multi-criteria evaluation framework. Methods are developed and identified to estimate the construction, agency, and user costs associated with the construction methods. A novel model was developed to allow the estimation of the construction and agency costs of ABC relative to conventional construction. This paper also demonstrates the estimation of user costs, including those associated with mobility, reliability, safety, and emissions, utilizing combinations of the proposed prediction method. The paper then compares the use of the return-on-investment and Technique for Order Performance by Similarity to Ideal Solution (TOPSIS) Multi-Criteria Decision Making (MCDM) evaluation approaches in the decision to select between ABC and conventional bridge construction. The results from the employment of the two approaches to a case study demonstrate the advantage of using the TOPSIS approach, which is also applicable in the urban planning process.

Sustainable production of precast combined pile-cap and column elements via statistical analysis of self-compacting concrete kinetics

This research applied accelerated bridge construction techniques to the Northern Mexico City Elevated Urban Toll Road. To this end, an 18-m precast combined pile-cap and column element was monitored during production. The recorded high internal temperatures raised concerns, which led to the extraction and testing of concrete cores, yielding satisfactory strengths. The kinetics during the setting and hardening of the three high-strength self-consolidating concrete mixes used in the production of these elements was statistically validated for the temperature range from 4.5 to 88 °C. In a previous study, new maturity functions were developed to predict the strength of equivalent mortars as a function of both the hardening time and isothermal curing temperature, which accounted for the crossover effect and provided better compressive strength predictions than ASTM C1074-11. These functions were applied herein to optimize the production, select the optimal concrete mix, and minimize the total construction time and environmental cost.

Accelerated Construction of Short Span Railroad Bridges in Iran

A comparison is made between the three conventional methods used for accelerated bridge construction (ABC) of railroad bridges in Iran: single-piece deck installation by heavy cranes, multisegment deck installation by cranes, and single-piece deck installation by the so-called roll-in or sliding method. Both the safety of the construction and the serviceability of the railway line during the construction process are the main factors influencing the appropriate alternatives. Four railroad bridge construction case studies are demonstrated and compared here. Based on the individual situations, it is shown that the use of the roll-in method, in comparison with installation by crane, can reduce the installation costs significantly, eliminate the fatigue-prone details of the steel connectors, and eliminate the time for concrete casting in conventional multisegment deck installations.

Application of Internal Curing in Cementitious Grouts for Prefabricated Bridge Concrete Elements Connections

Abstract Cementitious grouts are widely used in construction industry applications, including joint sealing, flooring, structural repairs, and field-cast connections for prefabricated bridge elements (PBE). The authors of this article have a strong interest in the latter application. PBEs facilitate accelerated bridge construction, increase safety, and minimize the inconveniences to the traveling public, while delivering a superior product. While these concrete elements are produced off-site with higher production levels, they rely on the field-cast grout material to complete the connections between them. The ideal grout for PBE connections is self-consolidating, has high early strength, good dimensional stability, good durability, and bonds well to precast concrete. The most common grout type used in PBE connections is based on cement or cementitious materials. This type of grout, however, has at times shown serviceability issues that are mainly associated with dimensional stability (primarily shrinkage), which might also influence the bond to the concrete element. The authors of this article are investigating the possibility of including internal curing (IC) in cementitious grouts with the aim of partially reducing or mitigating most of the shrinkage observed in these materials. The research discusses the particularities encountered in designing IC cementitious grouts, as opposed to conventional concretes, and evaluates the effect that IC has on several grout material properties with special focus on those relevant to PBE connection applications: shrinkage and bond. Results indicate that the inclusion of IC in cementitious grouts reduces both autogenous and drying shrinkage. The effect that this may have on the bond performance is also discussed from a mechanical and microstructural point of view. Finally, an initial cost analysis is provided.

New Connection Detail to Connect Precast Column to Cap Beam using Ultra-High-Performance Concrete in Accelerated Bridge Construction Applications

Accelerated bridge construction (ABC) is a paradigm change in delivery of bridges. ABC minimizes the traffic interruption, enhances safety to public and workers by significantly reducing on-site construction activities, and results in longer-lasting bridges. The use of precast elements is gaining attention owing to inherent benefits of accelerated construction. Designing an economical connection is one of the main concerns for these structures. New improved materials such as ultra-high-performance concrete (UHPC) with superior characteristics can provide solutions for joining precast concrete elements. In this paper two types of column to cap beam connection using UHPC are proposed for seismic and non-seismic regions. Among the merits of the proposed details, large tolerances in construction and simplicity of the connection can be highlighted which facilitates and accelerates the on-site construction time. The experimental program was carried out to evaluate the performance and structural behavior of the proposed connections. Four specimens were subjected to constant axial compressive loads and cyclic lateral loading. Results of the experiment showed that the displacement ductility of the specimens, incorporating suggested details, demonstrated adequate levels of displacement ductility. More importantly, the proposed connections prevented the damage into capacity protected element—in this case the cap beam. Analytical and nonlinear finite element analysis on the specimens was carried out to better comprehend the behavior of the proposed connections.

Static behavior of grouped large headed stud-UHPC shear connectors in composite structures

Accelerated bridge construction (ABC) utilizing precast systems offers many benefits such as faster onsite construction and lower traffic impacts. Ultra-high performance concrete (UHPC) becomes an innovative solution that facilitates some types of ABC. This paper proposes a novel steel-UHPC composite system and large studs with diameter of 30 mm. Push-out tests are conducted to investigate the shear behavior of large studs embedded in UHPC and compared with normal strength concrete (NSC). A total of 6 single stud and 18 grouped studs specimens are used to investigate the effects of casting method, precast deck strength, infilling material strength and transverse reinforcement in the shear pocket. Test results showed that grouped stud effect in the UHPC specimen was insignificant. Ultimate strength of grouped stud in precast UHPC deck was 10% higher than that of NSC precast slab while interfacial slip of UHPC specimen was 17% lower. Noting that grouped large studs better match with UHPC since no visible crack was observed at failure in UHPC slab while NSC slab displayed a number of cracks. Finally, load-slip relationship for large grouped studs embedded in UHPC was proposed based on experimental results and comparisons between the test results of strength and codes predictions were made.

FAST-PACED CONSTRUCTION OF THE NEW KHALIFA PORT BRIDGE PROJECT

The significant growth and development in the United Arab Emirates in recent years necessitated considering advanced construction techniques for bridge structures. This paper presents features of the New Khalifa Port Project which consisted of bridge structures with a combined length of 3.64 km. The strict project design criteria, schedule and budget represented significant challenges which required considering specific designs using efficient precast elements and construction methods. The bridge structural system consisted of 39.8 m long precast, pretensioned modified AASHTO (American Association of State Highway and Transportation Officials) girders with cast-in-place concrete deck slabs. The main challenge was to optimize the size of the precast girder as the self-weight of the initially proposed elements exceeded the lifting capacity of the available equipment. The other challenge was to correlate between the British Standards and AASHTO LRFD (load and resistance factor design) code to design the girders for static and dynamic loads. The casting yard was set at 70 km from the project site and delivery roads were assigned to accommodate the special tandems carrying girders weighing 80 tons each. Lessons learned during design, fabrication, transportation and construction of the precast girders add on to the efficiency of the Accelerated Bridge Construction (ABC) processes.

A New Precast Concrete Deck System for Accelerated Bridge Construction

Abstract Full-depth precast concrete (PC) deck systems have several advantages over cast-in-place concrete decks in bridge construction, such as improved product quality, reduced construction labor and duration, and less dependence on weather and site conditions. This article presents he development of a new full-depth PC deck system that overcomes the drawbacks of existing systems, which include large numbers of joints and openings that need to be field cast, a requirement for tight tolerances in panel production and erection, a need for an overlay, and a complexity of post-tensioning and grouting operations. The developed deck system consists of full-depth, full-width PC deck panels that are 12 ft (3.66 m) long to minimize the number of transverse joints that need to be field cast. Panels have covered shear pockets at 4-ft (1.22 m) spacing over each girder line. These pockets are designed to minimize the number of shear connectors and deck surface penetrations to eliminate deck overlay. Deck panels are prestressed in both directions: pre-tensioned in the transverse direction and post-tensioned in the longitudinal direction using a new approach that is ductless and easy to install. These unique features are expected to enhance deck constructability, durability, and economy. The article presents the deck system design, construction sequence, and laboratory investigations conducted prior to its implementation in the construction of the Kearney East Bypass bridge in the State of Nebraska, USA.