Accelerated Bridge Construction

The Special Collection on Accelerated Bridge Construction is available in the ASCE library (https://ascelibrary.org/page/jbenf2/accelerated_bridge_construction).

A significant portion of the existing roadway system in the United States was built over 50 years ago and is widely showing signs of increasing deterioration. The average age of the nation’s bridges is 43 and about 25% of 607,000 bridges in the US inventory are structurally deficient or functionally obsolete and need repair or replacement. Construction activities related to bridge replacement and rehabilitation are important contributors to traffic jams and reduced mobility and, most importantly, to safety hazards. Assuring the safety of the public needs to remain as number one priority by public agencies. In this regard, construction work zones are magnets for accidents and result in many accidents, causing injuries and fatalities for both the public and construction workers. Accelerated bridge construction (ABC) is a paradigm shift in bridge delivery, where reducing interruption to traffic and safety are given higher priorities. A total of 20 papers are published in this special collection, of which 17 papers are technical papers and 3 are case studies, with topics related to lateral slide, self-propelled modular transport (SPMT), superstructures, substructures, ABC connections, and inspection of ABC projects. The special collection of the Journal of Bridge Engineering focuses on the recent advances in research, design, fabrication, construction, and inspection of ABC projects.

Lateral slide is an ABC technique for the replacement of existing bridges in roadways with heavy traffic volume. In this technique, a new bridge superstructure is constructed on an offset from the existing bridge, then the existing bridge superstructure is demolished and the new bridge superstructure is slid in place over the existing substructure or a new substructure, which is built underneath the existing bridge prior to sliding the new bridge superstructure. There are two papers related to lateral slide in this special collection. The paper entitled “Friction coefficients for slide-in bridge construction using PTFE and steel sliding bearings” by Dorafshan et al. (2019a) describes an investigation of four parameters – surface roughness, lubrication, contact pressure, and sliding speed – influencing the coefficient of friction of bearing pads made of polytetrafluoroethylene (PTFE) and steel sliding surfaces. The takeaways from this study suggested that proper lubrication using either grease or oil is recommended for lateral slide with any surface preparation; furthermore, it was concluded that stainless steel with a #2B surface finish resulted in a lower coefficient of friction than either stainless steel with a rough rolled finish or hot-rolled carbon steel. In addition, it was found that the sliding speed has less impact on the sliding procedure; however, the contact pressure is inversely proportional to the coefficient of friction of the bearing pads. Attanayake and Aktan (2019), in their paper entitled “Procedures and guidelines for design of lateral bridge slide activities,” develop a detailed step-by-step design procedure for bridge lateral slide projects based on projects implemented in the State of Michigan and project documentation archived by the Federal Highway Administration (FHWA). The procedure is developed in a series of flowcharts addressing design consideration and suitable components for lateral bridge slides, which can be used to verify a complete design or initiate a new design that is beneficial to bridge designers.

SPMT is another ABC technique, which involves the use of a multiaxial platform that is controlled remotely by a computer. This platform can move, tilt, pivot, and carry preassembled superstructure to its designed position. Dorafshan et al. (2019b), in their paper entitled “Dynamic effects caused by SPMT bridge moves,” present the dynamics response of SPMT movements for simulated bridge transport for, to the author’s knowledge, the first time. The SPMT unit was loaded using steel weights with different weight capacities of up to 50%. The SPMT unit was instrumented using accelerometers for two types of motion, long run (LR) motion and start-and-stop (SS) motion.

The third ABC technique is associated with prefabricating bridge elements offsite, transporting them to the bridge site, and connecting them using dry or wet connections. Several bridge elements can be prefabricated, including footing, columns, bent caps, deck panels, and superstructure elements. This technique can be divided into three topics namely: (1) superstructure, (2) substructure, and (3) connections. A total of 13 papers related to prefabrication technique are selected for this special collection and are described hereinafter.

Three papers for superstructure systems are selected in this special collection. Balkos et al. (2019), in their paper entitled “Static and fatigue tests of steel-precast composite beam specimens with through-bolt shear connectors,” present an investigation of the static and fatigue performance of prefabricated superstructure a module consisting of composite steel girders with an integrated concrete deck slab. The composite interaction between the steel girder and concrete deck slab was achieved using different configurations of prestressed through-bolt shear connectors in lieu of welded shear connectors. The authors concluded that the through-bolt shear connectors did not fail during the fatigue testing; however, during the ultimate strength test, higher slip displacement was recorded at bolt fracture than for a corresponding girder with welded connectors. Another prefabricated superstructure is presented in the paper entitled “Experimental study on structural performance of prefabricated composite box girder with corrugated webs and steel tube slab” by He et al. (2019). In this study, the developed superstructure system is a box girder, which consists of (1) a bottom slab made of prestressed concrete-filled steel tube, (2) corrugated steel webs, and (3) concrete deck. The authors conducted experimental and analytical studies on the full-scale model and conducted live-load field tests. It was concluded that the flexural stresses are carried by the top concrete deck and the bottom slab; however, shear stresses were resisted by the corrugated steel webs. Huang et al. (2019), in their paper entitled “Seismic performance of precast prestressed concrete bridge girders using field-cast ultra-high-performance concrete connections,” describe an investigation of the seismic performance of an ultra-high performance concrete (UHPC) connection with spliced straight reinforcement between two full-scale pretensioned girders using shake table testing. It was concluded that the UHPC connection exhibited minimum damage during high-level ground motions up to an acceleration of 6.1g. In addition, the spliced reinforcement exhibited strains of less than the yield strain.

Five papers for substructure systems are selected in this special collection. Birely et al. (2020), in their paper entitled “Experimental behavior of reinforced concrete and pretensioned concrete bent caps,” report on a new approach for designing bent caps by applying pretensioning. The new concept of the pretensioned bent cap was examined through large-scale experimentation. The pretensioning was able to delay initial cracking and eliminate shear cracking. The same concept, applied to a bent cap with internal voids, is presented in the paper entitled “Experimental behavior of pretensioned bent caps with internal voids for weight reduction” by McKee et al. (2020). In this paper, to reduce the weight of bent caps during transportation and construction, internal voids in conjunction with pretensioning are suggested. It was indicated that both solid and voided bent caps had approximately the same flexural behavior; however, shear cracks were notably observed with brittle failure in the voided bent caps. It was also concluded that a higher level of prestressing could mitigate flexural cracks, with minor effects on shear cracks. Another paper, entitled “Impact response and capacity of precast concrete segmental versus monolithic bridge columns” by Do et al. (2019) presents a numerical investigation to compare the structural response to truck impact of prefabricated concrete segmental bridge columns and corresponding conventional columns. It was concluded that the segmental columns exhibited less damage than the conventional columns, owing to better energy dissipation. Mashal and Palermo (2019), in their paper entitled “Low-damage seismic design for accelerated bridge construction,” propose a new substructure system utilizing dissipative controlled rocking connections for high seismic regions. In this system, prefabricated bridge columns are connected to either bent caps or footing using post-tensioning and external metal dissipators. The new prefabricated substructure system was tested under cyclic loading and the specimen showed no residual drift or damage except for external dissipators. For repairing bridge columns, Farzad et al. (2019), in their paper entitled “Retrofitting of bridge columns using UHPC,” propose an innovative technique to repair damaged bridge columns by the use of thin layers of UHPC, which are applied to column concrete substrates. The authors tested 11 repaired bridge columns with different degrees of damage under combined constant axial load and incremental lateral loads. It was concluded that a thin layer of UHPC encasing the damaged ends of the columns is an effective repair technique, with no increase in column size.

Prefabricated bridge elements are connected to other adjoining bridge elements using onsite connections. Connections in ABC projects play a crucial role, as weak connections can cause service life issues and a need for maintenance in future. Besides, connections between prefabricated columns and capacity-projected bridge elements (either cap beams or footing) should be appropriately designed to avoid damage to these capacity-projected elements and to resist seismic loads in high seismic regions. Cheng and Sritharan (2019), in their paper entitled “Side shear strength of preformed socket connections suitable for vertical precast members,” describe on a study of the effect of different concrete surface preparations of column ends on shear strength between prefabricated columns and adjoining members (cap beams or footing) in socket connections with nonshrink, high-strength grout. The authors tested concrete surfaces as smooth, with exposed aggregates, and with two different configurations of deep-amplitude surface textures. It was concluded that the column ends with exposed aggregates performed the best of all the surface preparations. Another connection for connecting prefabricated bridge columns to prefabricated cap beams is suggested by Shafieifar et al. (2020) in their paper entitled “Investigation of a detail for connecting precast columns to precast cap beams using ultrahigh-performance concrete.” The authors suggest locating the connection outside the cap beam by splicing extended reinforcing bars from the cap beam with column reinforcement. For the suggested connection detail, UHPC is used to minimize the lap splice length. It was concluded that the proposed connection was successful in shifting the plastic hinge away from the cap beam; therefore, this connection is suitable for seismic and nonseismic regions. Pocket and socket connections between prefabricated bridge columns and footing were studied experimentally and numerically by Wang et al. (2019b) in their paper entitled “Seismic Performance of Precast Bridge Columns with Socket and Pocket Connections Based on Quasi-Static Cyclic Tests: Experimental and Numerical Study.” The test specimens were designed based on the actual application of precast urban viaducts in Shanghai, China. The authors concluded that both connections behaved similarly to cast-in-place columns. Shoushtari et al. (2019), in their paper entitled “Design, construction, and shake table testing of a steel girder bridge system with ABC connections,” present a study of the design and constructability of steel bridge systems with various ABC connections for substructures and superstructures for steel bridge systems for seismic regions. For substructures, rebar hinge pocket connections were used to connect the bottom of the prefabricated columns to the footing and grouted duct connections were used to connect the tops of prefabricated columns to the cap beam. For superstructures, simple for dead and continuous for live (SDCL) connections were used to connect the girders and cap beam with cast-in-place concrete and a top layer of UHPC, grouted blockout connections between the girders and prefabricated deck panels, and UHPC connections between prefabricated deck panels. The SDCL connection was studied in detail through cyclic testing of a component test specimen by Sadeghnejad et al. (2019), as reported in the paper entitled “Seismic performance of a new connection detail in an SDCL steel bridge system.” The authors describe experimental and numerical studies for the use of SDCL for seismic regions. The test results showed that the proposed connection conforms to the requirement for capacity protecting elements as the damage is formed in the plastic hinge region at the column end.

One paper related to bridge inspection is selected in this special collection, by Worley et al. (2019). In their paper entitled “Acoustic emission sensing for crack monitoring in prefabricated and prestressed reinforced concrete bridge girders,” the authors develop an acoustic emission testing technique for crack detection and monitoring for quality assurance or quality control (QA/QC) processes for prefabricated or prestressed concrete girders during construction, lifting, transportation, and erection.

Three ABC case studies are selected. Davis et al. (2019), in their paper entitled “Foundation reuse in accelerated bridge construction,” present six cases studies for the reuse of existing foundations in bridge replacement projects in the United States. Based on these case studies, the authors conclude that the reuse of existing bridge foundations can offer cost-saving options, less environmental impact, and faster construction; however, it could present challenges related to the need for assessing the conditions of the foundations, repair or retrofitting, and complicating risk analysis and decisionmaking processes. In another case study, by Nader (2020), entitled “Accelerated bridge construction of the new Samuel De Champlain Bridge,” the author presents an ABC case study for a cable-stayed bridge. The bridge towers utilized segmental construction for each pier leg with steel pier caps; in addition, prefabricated deck panels with cast-in-place closure joints were utilized in the bridge superstructure. A novel tower-girder anchorage (TGA) technique for self-anchored suspension bridge is presented in the paper entitled “Accelerated construction of self-anchored suspension bridge using novel tower-girder anchorage technique” by Wang et al. (2019a). In this technique, a midspan segment is connected first to the hangers, then the TGA device transfers the tension from the main hanger to the tower. This technique eliminates the need for temporary scaffolds underneath the bridge superstructure, reducing both construction cost and time for erecting and demolishing the temporary scaffolds.

The goal of this special collection is to advance the frontiers of ABC to effectively transfer the state of the art related to ABC to stakeholders. The special collection guest editor thanks the journal Editor-in-Chief Dr. Anil K. Agrawal and ASCE staff for their assistance. The guest editor thanks all anonymous reviewers for their time, effort, and constructive feedback, which contributed to the quality of each paper. The guest editor also thanks Dr. Islam Mantway for his assistance in preparing this special collection.