Accelerated bridge construction chapter 11 a review of chapters, river bridges, and conclusions

Accelerated bridge construction chapter 11 a review of chapters, river bridges, and conclusions Accelerated bridge construction chapter 11 a review of chapters, river bridges, and conclusions Accelerated bridge construction chapter 11 a review of chapters, river bridges, and conclusions Accelerated bridge construction chapter 11 a review of chapters, river bridges, and conclusions Accelerated bridge construction chapter 11 a review of chapters, river bridges, and conclusions

CHAPTER A Review of Chapters, River Bridges, and Conclusions 11 11.1  Introduction to chapter 11 This final chapter is divided into two parts Part 1: It deals with the summary and review of the first 10 chapters Part 2: It deals with rapid construction on rivers, using alternative float-in method to transport assembled bridge to the bridge site and timber and aluminum bridges Part is followed by overall conclusions Part 11.1.1  Summary of earlier chapters For early completion or for rapid construction, the main factors and issues discussed in the earlier chapters may be summarized as the five M’s, namely: Management team of design-build engineers, Modern materials using high-performance steel (HPS), high-performance concrete (HPC), and composites, Method of assembly of modular construction in factory or on site, Method of transport using self-propelled modular transporters (SPMT), and Method of erection by lifting into position, roll-in, roll-out or lateral slide-in For bridges on rivers, a float-in method can be used Both full and partial accelerated bridge construction (ABC) methods are discussed Partial ABC is a compromise between conventional and ABC methods It is applicable when sophisticated transport and lifting equipment is not available and where the bridge owner wants to keep the in-charge consultant Some factory fabrication of girders would still be used Since the scope of each project is slightly different, full ABC may not always be applicable The following types of conditions would exist:   A new bridge on a new highway Coordination with highway construction on one or both sides of the bridge will be required Bridge construction activities may not be on the critical path Also, no demolition work is needed Existing bridge requiring superstructure replacement only Only superstructure demolition may be required The ABC can be done using staged construction with limited lane closure Existing bridge requiring both superstructure and substructure replacement Staged construction may be required since existing footing width may interfere with the new footings Demolition of entire abutment footing would require shutting down of the entire bridge rather than lane closure Accelerated Bridge Construction http://dx.doi.org/10.1016/B978-0-12-407224-4.00011-3 Copyright © 2015 Elsevier Inc All rights reserved 489 490 CHAPTER 11  A Review of Chapters, River Bridges, and Conclusions C  onstruction duration for deep foundations such as minipiles or long piles or drilled shafts/ caissons will not change for full or partial ABC Funding will be unaffected in each case   Construction season may be geared to local weather and factory manufacture in doors will be an advantage Also, roll-in, roll-out method may be more expensive than lateral slide-in but has the advantage that the assembled bridge can be lifted and placed over the bearings without relocating the existing utilities Training programs in ABC may be necessary Use can be made of the Federal Highway Administration (FHWA) conferences, and lunchtime seminars organized by FIU and other universities engaged in research in the new technology A variety of case studies are presented for superstructure or substructure replacement using prefabrication, self-propelled modular transporters, roll-in and roll-out methods, and lateral slide-in methods A glossary of ABC terminology applicable to all the chapters is listed for ready reference in Appendix ABC Part will provide brief summaries of the chapters and will be the review of Chapters 1–10 The chapters that follow this introductory chapter on modern ABC will cover the following themes:   Sections 11.2 address coordination with highway construction schedule Sections 11.3 to 11.8 address scour issues related to river bridges and design of countermeasures The details related to scour are based on author’s textbook on Bridge and Highway Structure published by McGraw=Hill 2010 Section 11.9 provides details of case studies Section 11.10 is for the conclusion of the chapter 11 In addition, Section 11.11 discusses future developments of ABC Finally, Section 11.12 discusses acknowledgements and future revisions of codes/ Section Innovative Construction Methods (chapters to 4) (Chapter 2), Recent developments in ABC concepts (Chapter 3), Research and training in ABC structural systems (Chapter 4), Introducing innovative ABC techniques (Chapter 5), Modular bridge construction issues Section Recent Developments in ABC Concepts (chapters to 7) (Chapter 6), Rapid bridge insertions following failures (Chapter 7), Planning and resolving ABC issues (Chapter 8), ABC Prefabrication of the superstructure Section Modular Bridges (chapters to 11) (Chapter 9), Prefabrication of the substructure and construction issues (Chapter 10), Alternative ABC methods and funding justification   Chapter presents an introduction to modern ABC with discussion of the many advantages and deterrents Deterrents include administrative and planning bottlenecks, construction easements and right-of-ways, permit approvals, and utilities relocation issues Timely labor availability, weather problems, and the large storage yard areas required at the site are addressed In addition, the need exists for certification and training, laboratory testing related to the structural behavior of field connections of 11.1  Introduction to chapter 11 491 subassemblies, and mathematical modeling Design and construction codes, continuous funding, heavy cranes, and erection equipment such as trolleys and SPMTs are required to properly implement ABC Major benefits include reducing traffic impacts, and the use of prefabricated bridge components made of HPS, HPC, and other new materials and equipment Application of the latest techniques in concrete manufacture, including the use of lightweight concrete and other hybrid materials, will contribute to durability and possibly early completion of projects It was shown that applying the ABC methodology will result in 50% more completed bridges each year This will help the economy by reducing wasted man-hours due to traffic jams during construction; commuters will get to work faster, which will benefit commerce by promoting faster delivery of goods Primary and secondary consideration for the selection of suitable projects for ABC, in terms of benefit, are addressed Tables 1.2(a) and 1.2(b) give a format of criteria and allocating points in the point system Please see references to FHWA publications in Appendix (Bibliography) for Chapter for details In Chapter 2, we address recent developments in ABC concepts and their application to infrastructure We noted that it might be possible to reduce the number of failures with ABC by applying recent advancements in technology and innovative methods The failed bridges that were built using old technology can be rebuilt on a fast track using ABC It appears that there are hiccups that may be holding up a more rapid switch to ABC A slow but gradual shift from conventional methods to full ABC (with many projects utilizing a partial ABC approach) has been observed Each management subsystem, such as partial ABC, can be used to accommodate different circumstances and physical conditions ABC-related design needs to be made part of the American Association of State Highway and Transportation Officials (AASHTO) and state bridge design codes and specifications Deterrents and bottlenecks such as maintenance and protection of traffic (MPT), construction easements, right-of-way, permit approval, and utilities relocation need to be resolved, and administrative procedures further simplified to facilitate ABC There are many feasible applications of the latest techniques in concrete manufacture, composites, HPS, and hybrid materials that need to be promoted Integrated software that would cover all aspects of ABC, including design calculations and drawing preparation, should be investigated and developed to save engineering man-hours A surge has been seen in the manufacturing of bridge components and construction machinery worldwide FHWA has prepared a comprehensive ABC manual AASHTO grand challenges by the AASHTO Technical Committee for Construction (T4) present additional goals to strive for For bridges located on rivers, a survey of scour countermeasures that are being used nationwide was conducted A form was successfully developed to assist in the field assessment of scour at bridges Introducing more rapid inspections to identify deficient bridges by using remote sensors is emphasized Full-scale testing of joints in precast curved decks for both rectangular and curved decks is required Modifications to analytical methods applicable to discontinuities of components need to be developed Chapter also addresses design-build contracting system and the role of the Design-Build Institute of America (DBIA) in promoting ABC Construction Manager/General Manager system is described in Chapter Chapter emphasizes ABC logistics and training and research aspects For promoting ABC, design-build method of construction management is described in this chapter The role of the transportation agency in patronizing and promoting ABC is the most critical The consultant and specialized subconsultant roles come next; they introduce key innovations in design and field connections 492 CHAPTER 11  A Review of Chapters, River Bridges, and Conclusions This chapter reviews bridge rating procedures to identify deficient bridges and how to prioritize bridge repair Structural health monitoring methods using remote sensors will help prioritize bridges for rehabilitation The key factors dictating a particular type of delivery method include time restraints, level of risk, budget, and level of quality Preparing an evaluation matrix for selecting the type of fix or replacement would be helpful Innovative techniques need to be popularized and adopted as routine bridge construction Most accidents occur during bridge construction; hence rapid constructability requirements during erection need to be met, and preventive measures in design and construction to prevent failures need to be introduced ABC planning, analysis, and implementation methods vary for each of the structural systems and lead to many diverse applications for small, medium, and long spans, each of which has different construction durations and their own specialized construction methods Constraints in implementing ABC include MPT, approach slab construction, permits, and utility relocation; these are unavoidable constraints and should be on critical path for early completion The nature of manufacturing precast products creates a proprietary system and monopolistic environment, which may lead to unemployment of some number of construction workers Overemphasis of incentives/disincentives may pressure the contractor into adopting unrealistic schedules at the expense of quality control Certain improvements for economical design include the following:   • An upgrade to most modern construction equipment would be required • Current plan preparation and presentation should reflect ABC • Payment and accounting of pay items need to be accelerated • Arching action in deck slabs should be utilized—there is reserve strength that is being neglected • Deck overlays for riding surface quality—latex-modified concrete (LMC) or corrosion inhibitor aggregate concrete may be used • Bridge deck expansion joints for precast deck units should be investigated • Compliance with permitting regulations—environmental permits may hold the start of construction • Insurance against risk and liabilities is critical   Chapter describes training programs in ABC organized by DBIA It also addresses construction permits issues for air quality and water quality etc to be award by the Department of Environmental Protection (DEP) Chapters and also describe environmental issues Chapters and and Appendix (Bibliography) provide a list of relevant references on all aspects of ABC Chapter discusses how maintaining the right-of-way philosophy is achievable through innovative ABC techniques The chapter deals with design-build construction management, addressing modern concrete technology and the philosophy of maintaining the right-of-way at all times for all citizens There has to be a reward to promote innovation and encourage the undertaking of some risk The most recent initiatives and innovative techniques are described; they are promoted by federal agencies like FHWA and AASHTO as well as individual states, which are promoting the implementation of ABC for faster bridge delivery This chapter discusses a comparative study of conventional and innovative methods, along with a review of new design methods and the development of diverse repair technologies We look at modern construction equipment, the use of recyclable materials, and examples of recent ABC applications in the United States The scope of design-build (D-B) contracts and considerations 11.1  Introduction to chapter 11 493 of engineering ethics are also addressed We also discuss the important issue of ensuring adequate returns of the hundreds of billions of dollars of yearly investments in infrastructure through rapid bridge delivery Innovations help in upgrading the quality of construction and in completing the project in a timely manner A list of advancements in ABC methods include:   • Preventing bridge failures by minimizing the identified deficiencies through maintenance • Use of advanced methods, including computer-aided analysis and design techniques • Closer interaction between design documents and construction   Continued research efforts are required in resolving technical issues Common examples of innovative concepts that require continued study are ground-penetrating radar (GPR), staged construction, overhead and utility lines, environmental permits, road closures versus detours, precast and composite decks, and the use of stainless steel On the administrative side, new procedures for asset management, award of simultaneous multiple contracts, and accelerated highway construction (AHC) to accompany ABC were introduced in this chapter Using nanotechnology to reveal cracks and corrosion, searching for photographic evidence of defects, and using remote sensing technologies would certainly help in rapid bridge inspection and SHM There have been developments in the use of self-consolidating concrete (SCC), lightweight aggregate concrete (LWAC), recycled concrete aggregate (RCA) concrete, accelerated cure cast-in-place (ACCIP) concrete, blended cement concrete (BCC), fiber mesh concrete (FMC), reactive powder concrete (RPC), and rapid setting concrete (RSC) Researchers have developed special repair materials They include nonshrink, multipurpose and high-strength repair mortar Cementations materials concrete utilizes fly ash, blast furnace slag, and silica fume Examples of proprietary bridge systems include the robotic steel beam assembly system by Zeman, which has added a new dimension of structural steel fabrication and erection The system is designed for fully automated assembling, tack-welding, and full welding of structural steel elements Other systems include recycled plastic lumber bridges, lightweight titanium pedestrian bridges, Inverset, Effideck bridge decks, Exodermic bridge decks, and full-depth precast concrete deck panels (FDDP) Chapter addresses construction and rehabilitation using prefabrication, prefabricating bridge elements and systems (PBES) and various other improvements in the manufacture of ready-made bridges Prefabrication of bridges and their technical issues are discussed in Chapter There are many bridge companies in this area, such as CON/SPAN and Mabey-type temporary bridges Modular design and prefabrication have a number of benefits, including shorter production cycles and enhanced sustainability This results in lower production costs, with savings to be passed on to the client The use of eco-friendly materials and prefabricated design also make these modular structures ideally suited to the changing demands of the transportation industry Consider sample projects using the following bridge elements as guidance in the absence of an ABC code of practice:   • Precast foundation elements • Precast pile and pier caps • Precast columns • Precast full-depth deck slabs 494 CHAPTER 11  A Review of Chapters, River Bridges, and Conclusions • Cored slabs and box beams • NEXT beams and deck girders • Full-span bridge replacement units with precast deck • Bridges installed with SPMTs   Cost evaluations are important and should be accurate They should include the following categories:   • Time and materials estimates • Roadway user costs • Maintenance of traffic costs • Safety costs • Agency costs • Life cycle costs   If the cost of ABC is not greater than 30% of the conventional bridge construction cost, strongly consider ABC The benefits are in early delivery, improved quality, and longer bridge life Take advantage of existing technologies, such as Inverset and prefabricated fiber-reinforced polymer (FRP) deck ABC methods have evolved ahead of the design codes Research is required in many aspects, including:   • Developing strengthening methods and corrosion mitigation techniques, including fabricating stronger girders by eliminating the need for shear stiffeners with the use of folded web plate in steel girders • New methods to monitor and strengthen foundations against scour, earthquake, and impact • Developing and reviving the concept of full canopy on bridges to facilitate mobility, improve drainage, prevent skidding, and eliminate the use of deicing agents   Chapter deals with rapid bridge insertions following failures This chapter addresses the reasons for numerous failures of bridges in United States and abroad, which can be prevented by the introduction of new technologies of ABC Maintenance can avoid failures or at least warn of failures in advance Use of remote sensors to monitor structural health is desirable Early failures in conventional construction can be attributed to a variety of reasons, both administrative and technical Studies shows failures resulting from inadequate oversight of projects, a lack of supervision at the site, design errors, lack of comprehensive codes, contractor’s last-minute decisions to meet hasty schedules, and limited resources Most failures occur during construction due to lack of redundancy in design, inadequate construction, and lack of contracting experience and knowhow Alternate ABC contracting methods are described in Chapters and As discussed in this chapter, bridges on rivers failed more than those located on intersections, due to soil erosion Use of HEC-23 countermeasures is on the rise Deep foundations are preferred over shallow foundations for bridges that are scour critical Scour countermeasures need to be designed according to HEC-23 and provided to protect footings When replacing an existing superstructure, deck elevation may be raised by 1–2 ft Some progress has been made in making bridges seismic resistant by using lightweight materials and isolation bearings The large volume of site work in conventional construction is minimized by ABC, which requires as much work offsite as possible 11.1  Introduction to chapter 11 495 Use of modern technology: Bridge engineering is changing with time New technology and innovative ideas developed in the last two years need to be adopted In planning bridges, cost is still the main criteria Much of the cost goes into the foundation and substructure concrete construction The use of new and stronger construction materials such as HPS, HPC, and Ultra HPC and FRP decks should be encouraged, as these are more durable Shallow-depth girders will result, which are lighter in weight Galvanizing will reduce corrosion Currently, rolled sections in HPS 70W and 100W are not available or are too expensive Welded girders in HPS are being used Prestressed concrete box girders are stronger in torsion and cost-effective, especially with the use of lightweight concrete; they also lower maintenance costs Also, composite construction, for example using the Inverset system, is more economical and on the rise Precast integral abutment construction requires greater attention Peak stress and deformation can be checked prior to lifting The location of cranes needs to be identified on contract drawings Project management, quality control, and MPT are of critical importance It was observed that the professional relationship between owners, contractors, and consultants needs improvement through increased communication ABC design-build methods are a step in the right direction Widening of highways in urban areas is not always an option Right-of-way and legal issues are involved to acquire new land Hence, underpass and/or double-deck highways are often used to overcome the additional lanes problem and traffic congestion once and for all Safety checklists: It is critical for personnel to be safe and healthy at construction sites A checklist of do’s and don’ts needs to be prepared and issued Erection methods for curved girders are also described in Chapter Chapter addresses ABC planning and construction issues Our failing infrastructure and transportation problems are discussed in this chapter Before launching a multimillion dollar project, it is the professional responsibility of engineers to conduct an effective planning exercise The continued and ever-increasing infrastructure difficulties faced by the public are highlighted The economic and public comfort benefits derived from early completion of projects are reviewed A survey of ABC projects successfully completed in many states illustrates an increased interest in adopting the new technology Major contractors and fabricators have welcomed the increased responsibility of the design-build system in which their decision making is appreciated The progress of design-build system and MPT issues are described in Chapter Various aspects of the contractors’ role such as that of Construction Manager/General Manager are described in Chapter Partial ABC: For rehabilitation of an existing bridge, an engineer’s options are restricted as compared to the options available for design of a new or replacement bridge But partial ABC is still possible The huge funding issues can be partly overcome by public-private partnerships The focus of Chapter is on bridge superstructure prefabrication, several aspects of prefabrication of the superstructure and includes the stakeholders of ABC The reasons for its success are as follows:   • The contracting industry is not afraid to take the lead in the management of small- and mediumsized projects and is willing to take the necessary risks and meet challenges that inevitably arise • There have been developments in special transportation methods for long and wide loads using SPMT In addition, heavy capacity cranes for lifting and erection are now available 496 CHAPTER 11  A Review of Chapters, River Bridges, and Conclusions • Organizations such as FHWA (with their Every Day Counts Program and ABC Handbook), Transportation Research Board (TRB) and AASHTO have been a motivating factor • The design-build contract system helps in the adoption of prefabrication According to SHRP2 Project R04, ABC is the clear choice Life cycle costs are significantly reduced   Promoting modular construction: European practice is to standardize the design of bridges on typical intersections (limiting them preferably to two spans) and wherever possible on river bridges as well The location of abutments can be adjusted to utilize standard precast girder lengths The location of field connections are also kept unchanged as determined from analysis A list of recent innovations is presented for selection and for further action and implementation, such as:   • PBES • Connection details for PBES • NEXT beams, spliced girders, bulb tee, and Wolf girders • Structural placement methods • Launching, sliding, and heavy lifting   On-site construction under open sky is far more difficult than factory manufacture New bridges have become more complex since the bridge practice of a century ago, when cast-in-place (CIP) construction was the only option Today a medium-size factory would likely have the necessary facilities for indoor fabrication Some of the difficulties involved in on-site construction include:   Extreme events and climatic hazards: Most of North America has a subzero cold climate for four months of the year, and southern states have high temperatures in the summer This may slow down the speed of outdoor work In large factories, temperature change does not affect the schedule for construction Also, activities on the critical path are not affected Labor availability at remote locations: Most bridge sites are located on distant highways Hundreds of members of the labor force cannot be relocated The factory is their regular workplace Storage of construction materials: A special building is required on-site for storing construction materials such as aggregates, cement bags, ladders, machinery, and dozens of other appliances Temporary pathways need to be constructed This adds to the schedule Formwork: This is an expensive item of CIP construction It needs to be erected for the deck slab and for the CIP girders This adds to the cost of work and affects the schedule Exposure to rain and sunlight: Due to the exposure of steel and cement to the elements, corrosion of steel and wetting of cement, etc., takes place, which lowers the quality of work and is not desirable Mobilization: For CIP, a temporary administration building needs to be set up This adds to the overhead   Other issues covered in Chapter include the following:   Wider use of the P3 system: With the P3 approach, required funding is made available to replace hundreds of these bridges more quickly Introduction of new maintenance and planning techniques: The causes of structural deficiencies, functional obsoleteness, and bridge failures need to be investigated Methods to prioritize the planning of structural systems and introduce rapid construction need to be researched Structural health monitoring (SHM): This is a new technology for bridge inspections that uses lasers and remote sensors Bridge inspectors need to be trained in the use of computer software 11.1  Introduction to chapter 11   497 that operates such remote sensors, as well as radar technology and Lidar techniques that can quickly obtain information about the fatigue and stress-strain history of a bridge This approach will make bridges safer and reduce life cycle costs Overload prevention and review of live loads: In light of the latest advancements in the truck industry, it has become important to assess the magnitude of axle loads on highway bridges and also update the military live loads on military routes due to new tanks American Society of Mechanical Engineers design codes need to be reviewed Use of high-friction surface: Introducing the British-invented surface treatment on asphalt pavement to create a high-friction surface and favorable friction properties between vehicle tires and bridge deck surfaces will help in braking and prevent skidding Binders such as thermosetting epoxies are used Maryland has successfully introduced plates on their intersections Chapter deals with substructure prefabrication techniques and construction management The progress in using prefabrication has been slower for substructure construction compared to that for superstructure construction, especially for longer span bridges It is easier to transport horizontal bridge beams and slab panels on an SPMT than vertical pier bents due to their size Also, post-tensioning may be required for the substructure panels to make them watertight For emergency bridge replacements on important routes after floods, earthquakes, or accidents, etc., prefabrication of both pier and abutment members would help Other key aspects of prefabricated substructure planning and management include:   Soil report: Since foundation design requires soil investigation, this operation should be started well in advance by the owner even before the award of the contract Utility pipes: Advance coordination with the utility companies for supporting their pipes and transferring from pavement elevation to deck elevation is required Deck drainage: The method of disposal of rainwater from the deck into public sewers also needs to be planned Electrification: If deck lighting is provided, the power supply needs to be arranged from the electric supply company and negotiations need to be started in advance, as the prefabrication activity is in progress Precasting concrete and welding: Although prefabrication in a factory may not take as much time as cast-in-place construction under the site conditions, the time required for the plan layout of rebars, the curing of concrete components, and the welding of steel members, etc., remains unchanged Planning: The additional time required to plan a route, obtain permits for heavy and wide loads, and apply for police escort, as well as the hauling distance for the prefabricated bridge from the factory to the site need to be taken into consideration Hauling heavy loads: Loading prefabricated components onto the SPMTs and unloading them at the site as well as the required lifting and placing operations by the special cranes on-site need to be taken into account in the overall schedule Stay-in-place formwork: The additional time and cost for hauling, lifting, and placing needs to be analyzed in comparison to the cast-in-place construction erection time for temporary formwork or using permanent stay-in-place formwork to make prefabrication as economical as possible Modular construction: The greatest benefit of prefabrication is for small spans, where the hauling and lifting problems are fewer and pier construction is avoided Arch structures combine superstructure girders with substructure curved columns and are more aesthetically pleasing 498   CHAPTER 11  A Review of Chapters, River Bridges, and Conclusions Leading prefabrication companies: There are a wide variety of bridge manufacturing companies in the United States who have developed specialized bridges for repeated use Examples include High Steel Structures, Acrow, Jersey Precast, and CON/SPAN Need for standardization: AASHTO specifications have recommended minimum vertical and horizontal clearance requirements Similarly, many states have developed standard details for lane widths, shoulder widths, and bicycle tracks, spaces for plants and flowers, etc Span length alternatives to conform to the width of the highway can be used to standardize bridge lengths Such ready-made standard span structures using concrete and steel can be made available off the shelf and ready for delivery to sites, as required A choice of colors is also available for aesthetic requirements Quality control: Construction drawings for precast substructures are more specialized than conventional construction drawings Typical review comments on reinforced concrete detailing of abutment walls, pier caps, and columns are therefore necessary Examples of necessary quality control measures are review by expert bridge engineers of the connection details, location of hinges, seismic detailing, lifting points, etc Case studies of a variety of bridges using PBES for the substructure in the United States are summarized in Chapter Foundation drawing reviews: Expert reviews can raise a number of issues and lead to various recommendations Some of these include the following:   • Foundation design is too expensive; footings are too big/deep Review soil report • Monitor compaction before placing footings Consider soil improvement techniques • Always get soil borings and a geotechnical report before foundation design and have geotechnical oversight and testing during construction • Use deep piles or drilled piers • Use caissons or auger piles • Use tied spread footings • Check for retaining wall failure from settlement and overturning   Alternate ABC contracting methods are also described in Chapter Various aspects of engineering management are presented, such as asset management (Chapters and 10), disaster management (Chapter 3), design-build (Chapter 4), bridge failures and risk management (Chapter 6), and construction management (Chapter 9) Chapter 10 addresses evaluation criteria for deficient infrastructure and alternative ABC methods ABC technology is still developing, although significant progress has been made in prefabrication This chapter highlights important alternatives to the well-established use of factory prefabrication and SPMT, such as transportation by barges and lateral slide-in methods The many impacts of rapid construction and traffic volume and lane closures are also given in Chapter 10 In some cases it may be warranted to use lateral slide-in methods due to the limitations of transporting large bridges by road or on rivers for long distances and fitting them on SPMTs or barges The method consists of site casting adjacent to the existing bridge on temporary bents, followed by the use of mechanical devices for sliding or the use of cranes to lift the superstructure in position Case studies have shown that many states have successfully used this modern technology A few states like Utah and Oregon have developed special provisions as part of their construction specifications In some cases it is possible to construct abutments prior to slide-in of the new bridge, leading to further time savings 11.8  Scour countermeasures for new bridges 529 The following important issues need to be resolved for the successful installation of countermeasures:   • Permit identification • Right-of-way identification • Relocation of utilities • Construction coordination   11.8.1.4  Traffic and utilities issues related to the use of riprap Site access: Adequate access to the site should be provided for trucks to deliver riprap Right-of-way: Construction easements and right-of-way access may be required for the duration of construction Detours: Detours, lane closures, or nighttime work may be necessary Coordination with traffic control may be required Emergency vehicles and school bus services should not be affected by lane closures Delay to ABC due to interference from underground utilities: Coordination with utility company should be made fairly early in the construction process Installation and maintenance of underground utility pipes close to a bridge foundation can cause significant disturbance to the soil and should be checked If any interference is likely with the proposed countermeasure and utilities need to be relocated, this may result in an environmental issue Relocation of any utilities at the sides of an abutment or a pier may be necessary for the duration of construction 11.8.2  Use of riprap countermeasures The following documents are good resources on the use of riprap as a countermeasure:   • Publication No FHWA-RD-91-057, “Stability of rock riprap for protection at the toe of abutments located at the floodplain,” 1991 • HEC-11, “Design of Riprap Revetment” • Design Guidelines and 12 of HEC-23   Spill-through abutments: For spill-through abutments, extend the riprap around the abutment and down to the expected scour depth The launching apron at the toe of the abutment slope should extend along the entire width of the abutment toe and around the sides of the abutment to a point of tangency with plane of embankment slopes The apron should extend from the toe of the abutment into the waterway a distance equal to twice the flow depth in the overbank area near the embankment, not exceeding 25 ft Figures for typical layouts of abutment riprap for abutments near a channel bank, stub abutment near the top of a high channel bank, and abutment near a flood plain are given by the Maryland State Highway Administration Design of riprap at bridge abutments: The author developed a Handbook of Scour Countermeasures for NJDOT with Anil Agrawal of City University, New York It was approved by FHWA for use by consultants (Publication No FHWA-NJ-2005-027) In New Jersey, due to high risk of movement of riprap, riprap alone is not recommended as a permanent countermeasure but as emergency shielding only for a period of five years or longer only after regular evaluation from underwater bridge inspection reports Riprap can be used as secondary local armoring, in conjunction with primary structural countermeasures or with river training measures 530 CHAPTER 11  A Review of Chapters, River Bridges, and Conclusions Limitations on the use of riprap monitoring: Riprap shall be used as a countermeasure only if accompanied by field inspection that occurs immediately after floods and by the use of monitoring equipment during floods   Critical velocities: If a 100-year flood velocity exceeds 11 ft/s, riprap should not be used Scour depth: If calculated scour depth is high and excavation to place riprap under the riverbed would endanger the stability of soil adjacent to the footing, riprap should not be used Economic considerations: If riprap is not available locally or at a reasonable distance, it may not be economically feasible In such situations, other alternatives may be considered Also, if cost of hand placement of riprap is high, other less expensive countermeasures may be considered Dumped riprap: Truck-dumped riprap can easily get dislodged during floods and get washed away due to high velocities It is less stable compared to hand-placed riprap, and its use is therefore not recommended 11.8.3  Riprap detailing • Construction drawings have to be prepared Conceptual sketches for the layout of riprap with details for riprap placement at abutments and piers based on HEC-23 or the applicable state handbook should be used • In addition to hydraulic data, construction drawings should show tables summarizing flood elevations, flood velocities, and scour depths • Maximum side slope is 1V:2H, although where excavation is difficult, 1V:1H may be used with fractured rock • Cost factors: The current estimated cost is $350 to $450 per square foot of the plan area of countermeasure Long-distance freight charges for riprap may increase the unit cost by 10% 11.8.4  Recommended river training countermeasures Depending on flood conditions, the following types are recommended:   • Retard (earth, timber, and steel sheet piles) • Channel improvements (channelization) • Guide banks/guide walls   The final selection should be made based on project-specific conditions 11.8.5  Design of common types of countermeasures Gabions can be sized according to NJDOT Soil Erosion & Sediments Control Standards fusing Table 11.9 11.8.5.1  Articulated concrete blocks Design guidelines for articulated concrete blocks (ACB) for abutments are based on Design Guidelines in HEC-23 Design guidelines for ACBs for piers are based on NCHRP 24-07 Other recommended sources of information on design of ACBs are HEC-11 and McCorquodale (1993) 11.8  Scour countermeasures for new bridges 531 Table 11.9  Soil Erosion & Sediments Control Standards for Sizing Gabions (Estimate of Velocity can be Provided by Experimental Verification from more than one Suppliers of Gabions) Gabion Thickness (ft) Maximum Velocity (ft/s) ẵ ắ 11 14 11.8.5.2 Concrete armor units/A-jacks The basic construction element of A-jacks for pier scour applications is a “module” comprised of individual A-jacks which are banded together in a densely interlocked cluster, described as a 5 × 4 × 5 module The design procedure for A-jacks systems for pier-scour protection is stated in Design Guidelines of HEC-23 11.8.5.3  Design procedures for grout bags The design size of a bag or depth of a layer depends upon the following:   • A design flood velocity of 5–10 ft/s • A computed scour depth for contraction and local scour of 3–6 ft • When hydrostatic pressure builds up, the dead weight of bags should exceed the uplift pressure The mattresses should be provided with filter drains or drain holes for pressure relief • Depending upon the application, bags may vary in capacity, from standard cement bag size, to about 5 ft3, while mattresses are larger in size up to 15 ft3 in volume • Mats must be bound firmly to the pier itself for good performance Mats should be installed with their top surfaces flush to the bed • Grout bags should be sized and placed in a manner similar to riprap, and underlain by a geotextile filter with a partial cover or filter layer Any means to render the surface of bags rough and angular will aid performance • Properly sized bags are more effective when they extend a single layer of protection laterally, rather than if they were stacked Efforts should be made to avoid stacking of grout bags • Flexible bags of sand may be preferable to grout-filled bags   Replacement or new bridges: Field inspections will show that certain components of a bridge may need repair, retrofit, rehabilitation, or replacement For safety reasons, railings, parapets, deck slab, bearings, or superstructure may be recommended for replacement In some cases, the entire bridge may require replacement Any new design of superstructure and substructure components will require an analysis for bending moments and shear forces New live loads are based on a family of trucks, namely mandatory HL-93 loads, Permit, Military, and applicable state Legal loads (Type 3, Type 3-3 or Type 3S2 Vehicles) 11.8.5.4  Use of cofferdams If the water depth is not high, temporary cofferdams may be required for construction in dry conditions Without dry conditions, the quality of placement of countermeasures will be difficult to monitor or maintain Figure 11.9 shows a section view of a typical cofferdam 532 CHAPTER 11  A Review of Chapters, River Bridges, and Conclusions 11.8.5.5  Sheet piling left in position For underwater construction of the abutments and pier types, temporary sheeting on the streamside is required for installing CMs at the sides of spread footings/pile caps To prevent long-term scour, temporary sheeting may be left in place after CMs installation is completed Debris and silting may reduce river width and increase flood velocity and water pressure on piers Considerable repairs as shown in Table 11.10 will be required 11.8.6  Technical specifications and special provisions Technical specifications deal with description of materials, method of construction, units of measurement, and unit costs Countermeasures that are proprietary in nature may be obtained directly from vendors, if they are not available in state-standard specifications They are required for preparing Optional bracing system (Typ.) (Post & Struts Not Shown) Substructure* Design water El (50 Year Flood) Wale El Wale El Substructure* Steel sheetpile Min AZ 18 ASTM A572 (Typ>) Tip El Tip El FIGURE 11.9 Cofferdam schematic section using rolled AZ sections (Heavier sections may be required depending upon the depth of water) Table 11.10  Typical Examples of Proposed Concrete Repairs (In Addition to Remedies Proposed in Table 11.8) No Deficiencies Reported in Underwater Inspection Reports Spalls in abutment concrete Delaminations and cracks in substructure concrete above water Voids in breast wall Mortar loss in masonry joints Broken stone masonry Cracks in tremie concrete below water Spalling in foundation Cracks in apron around piers Proposed Repairs Surface repairs with approved patch material Pressure grouting Epoxy grouting/use nonshrink grout Repointing mortar Replace stone and fill with mortar Pressure inject masonry cracks Pressure grouting Repair concrete apron or place riprap around piers 11.9  Case studies and ABC research 533 contract documents and for award of contracts The designer should use guidelines provided by the manufacturers only after they have been approved by the engineer in charge for the project Recommended guidelines should be supplemented by design data provided by the manufacturers for designing such countermeasures Technical specifications for gabions should be used Gabions are being frequently used in place of riprap Any deviations from standard specifications need to be approved as special provisions Caissons may be preferred over piles For long-span bridges on harder ground and dense soils, drilled piers will be more resistant to erosion compared to caissons Integral abutment piles with a single row of piles would require greater protection by providing shielding in the form of sheeting left in place 11.9  Case studies and ABC research Bridges are complicated to replace while keeping traffic flowing, but the Massachusetts Department of Transportation (MassDOT) has found a way to minimize the pain Figure 11.10 shows postflood scenario when sediment and debris accumulated mainly at the downstream of bridge Scour analysis needs to be based on HEC-18 aggradation procedures ABC is being used on the Phillipston Bridge in Massachusetts, and it is reducing construction time from years to months This method involves building the bridge or the major bridge elements nearby When the new bridge is ready, the existing bridge is demolished and the new bridge is eased into place using cranes and self-propelled trailers Although the bridge is shut down completely, the duration is only 202 h rather than weeks or months Design-build Team Relationship: One of the keys to this ABC method working smoothly is the design/build relationship between the designer, in this case TranSystems, and the contractor, SPS New England Their ability to work together has proven as time saving as the method of construction Problems are solved and avoided when we work together FIGURE 11.10 Post-Hurricane Floyd flood scenario: Aggradation at Peckman’s River Bridge on Route 46, New Jersey (Photo by author.) 534 CHAPTER 11  A Review of Chapters, River Bridges, and Conclusions Precast concrete abutment caps and approach slabs were placed after the demolition of the existing bridge superstructure to facilitate the rapid installation of the new superstructure Precast barrier rails sections were used to bridge between the CIP rails on the approach and on the bridge structure Precast concrete abutment caps, approach slabs, and barrier rail sections were produced by J.P Carrara & Sons, Inc., Middlebury, VT This project was started in May 2010, and the new bridge was in place on November The Phillipston bridge proves that ABC is a doable system that effectively replaces a deteriorating bridge without the costly and irritating traffic delays This is now a proven success and MassDOT has several more of these projects on the drawing board 11.9.1  Hurricane Sandy damage repairs According to a Reuters report dated December 6, 2012, lawmakers and transportation officials said that billions of dollars are needed to strengthen and repair rail and other transportation networks in the U.S Northeast in the aftermath of savage Superstorm Sandy “Estimates of the damage have reached more than $7 billion Across the region, train tunnels, stations, and rail yards were flooded, rail tracks were damaged and critical equipment was ruined,” Senator Frank Lautenberg, a New Jersey Democrat, said at a Senate subcommittee hearing on storm damage Hundreds of millions of gallons of salt water flooded the city’s subway system, which is more than one hundred years old, the chairman of New York’s Metropolitan Transit Authority told the panel New Jersey’s transit agency estimates that Sandy caused nearly $400 million in damage to its networks That breaks down roughly into a little more than $100 million for rail equipment, including rolling stock, and some $300 million to fix and replace track, wires, signaling, electrical substations and equipment, as well as to cover the costs of emergency supplemental bus and ferry service and lost revenue, Another $800 million is needed “to mitigate and harden the transit system to make it more resilient to future storms.” So there is a need to apply ABC for the large volume of work generated by Sandy on an e­ mergency basis 11.9.2  Substructure construction products by Contech For bridges on rivers, both erosion and sedimentation controls are required A range of construction products from CONTECH are shown Other contractors in this specialized work are also available   • Geosynthetics for Earthwork • Erosion and Sedimentation Controls • Erosion Controls • Geosynthetic Slope Protection • Driven Piles • Composite Piles • Retaining Walls • Foundation Drainage • Subdrainage Piping • Underslab Drainage 11.9  Case studies and ABC research 535 11.9.3  ABC in seismically active states See “Innovative Technologies and Their Applications to Enhance the Seismic Performance of Highway Bridges: Precast, Segmental Bridges for Accelerated Bridge Construction in Seismic Regions (Project 020)” by George C Lee, Civil, Structural & Environmental Engineering, University of Buffalo   There are no design procedures or guidelines for ABC (such as the types of connection details between vertical and horizontal members) in seismically active states Typical seismic resistant connections are using bar couplers, using pockets or recess, using socket connections, using grouted ducts and using integral or hybrid systems The connection details with the required tolerances can be more easily achieved in factory conditions than in the field thereby improving quality control Thus, MCEER’s research work focuses principally on the development of seismic design guidelines for prefabricated reinforced concrete and segmentally constructed highway bridges of short- to medium-span length Analytical and experimental work is being carried out to formulate design guidelines for practical applications so that all states can benefit from the use of ABC These efforts include the evaluation of existing bearings for their long-term performance under various environmental conditions, the deployment of a new generation of bridge bearing developed under a previous FHWA research contract, and exploring the concept of using a structural fuse to protect bridges from extensive damage in the event of an earthquake The MCEER research project funded by FHWA is a group effort carried out by a number of investigators in the Department of Civil, Structural and Environmental Engineering at the University at Buffalo and coordinated by George Lee   11.9.4  Rapid bridge erection over rivers Figures 11.11 show examples of bridge erection over rivers using heavy cranes Some of the bridges are of proprietary design, which is now becoming popular for the smaller spans 11.9.4.1  12th Street Pedestrian Bridge, Oakland, California This beautiful bridge is a dark-colored “Fir Green” and is 15 ft wide by 146 ft long! The bridge was built as one standing structure that was eventually split up and shipped as four pieces After arrival, it was erected on-site and set into place The bridge sits adjacent Lake Merritt, a large tidal lagoon that lies just east of downtown Oakland, California 11.9.4.2  Jackson Hill Street Bridge, Houston, Texas Located near Jackson Hill Street in Houston, Texas, this pedestrian bridge is 10 ft wide by 345 ft long and spans Buffalo Bayou Park as part of the Buffalo Bayou Partnership 11.9.4.3  Cheyenne Ave Bridge, Las Vegas, Nevada This prefabricated pedestrian bridge is located in Las Vegas, Nevada, crossing Cheyenne Avenue This steel truss bridge is fully enclosed and painted for durability and beauty 536 CHAPTER 11  A Review of Chapters, River Bridges, and Conclusions FIGURE 11.11 High-capacity crane lifting the assembled truss 11.9.4.4  Ojai Valley Trail Bridge The recent installation of this Greenwood, South Carolina, bridge showcases the original “tied arch” bridge design as beautiful and strong The arch’s geometric shape provides the strength that allows the bridge to reach its incredible span of 244 ft with a 10-ft deck width The bridge is fabricated from weathering steel with a pressure-treated wood deck providing its natural and timeless look The installation took place in Greenwood adjacent to the beautiful hunting club “The Territories.” 11.9.5  Partial ABC for the world’s tallest lift at Staten Island, New York Raising the road bed of the Bayonne Bridge 64 ft while traffic continuously flows across the span is unprecedented in the annals of engineering; a unique set of circumstances, starting with the bridge’s design more than 80 years ago, has made this project possible Upon completion, the bridge will include four 12-ft wide lanes—two in each direction—a 12-ft wide pedestrian/biking path, nearly 5-ft wide shoulders on each side, and the possibility of a future light rail The span currently has the lowest navigational clearance of any bridge in the area and one of the lowest in the country at 151 ft Raising it to 215 ft above the Kill Van Kull will put it more in line with the average of about 290 ft nationally or closer to its immediate neighbor the Verrazano-Narrows Bridge, which sits about 217 ft above the water depending on the tide The span crosses the busiest shipping channel on the East Coast of the United States, which sees 30% of shipping traffic from Maine to Florida navigate under it and supports 280,000 related jobs Portable sound barriers have been put in place around work areas to mitigate some of the construction noise, and the contractor measures noise levels with meters 11.9.6  Examples of research projects at the New Hampshire DOT The NHDOT Project Information Center is a source for information about ongoing and planned Department of Transportation projects Other states are also investing in new projects to promote ABC 11.9  Case studies and ABC research 537 technology with the view that research results will pay back the funds’ investment in terms of confidence from laboratory model tests, economy through developing design procedures, and resulting safety during construction and under live loads, especially for the untested newer ABC technology 11.9.6.1  Substructure and scour projects Examples are:   • Estimation of Flood Discharges at Selected Recurrence Intervals for Streams in New Hampshire • Field Performance Evaluation of Pile Points • Ground-Penetrating Radar to Detect Pre- and Postflood Scour in NH • Pier-Scour Measurement Methods and Predictions at New Hampshire Bridge Sites • Ground Vibrations Emanating from Construction Equipment • Effectiveness of a Pile Driving Analyzer for Determining Pile Capacity in NH Soils • Enhancing Geotechnical Information with Ground Penetrating Radar • GIS and the New Hampshire Rock Cut Management System • Effect of Freeze-Thaw and Frost Heaving on Flowable Fill 11.9.6.2  Superstructure and traffic projects Examples are:   • New Hampshire Road Weather Information System (RWIS) • Fiber Reinforced Polymer Demonstration Project and Bridge Deck Test Facility • Bridge Deck Evaluations Using High Speed Ground Penetrating Radar • Concrete Cover Determination Using Ground Penetrating Radar • Ground Penetrating Radar for Delineating Bridge Deck Repair Areas • Mitigation of Alkali-Silica Reactivity in New Concrete in New Hampshire • New Hampshire’s Concrete Aggregate and Alkali-Silica Reactivity—Statewide Assessment of Fine and Coarse Concrete Aggregate • Shrinkage Characteristics of Concretes with Type K Cement, Mineral and Chemical Additives • Frost Susceptibility of Recycled Crushed Glass Aggregate Mixtures   Construction methods for bridges have been undergoing many changes over the centuries From laying timber logs and tying ropes at each end to sophisticated beam, arch, truss, cable tied and suspension bridges and from partial ABC to full ABC The objectives are safety, economy and public comfort of the millions of users Construction materials used are timber, aluminum, steel, reinforced and prestressed concrete Composite and hybrid bridges are of more recent origin Types of construction involve minor repairs to rehabilitation, retrofit and replacements or new bridges on new highways Bridges on waterways are more difficult to construct due to floods and soil erosion than those on two way intersections Environmental permits are required for construction and need to be obtained from DEP before construction commences Changes in design may be required Substructure and foundation usually take longer to build than the superstructure It is always a matter of team work In selecting a team, experience in ABC methods and minimum bid cost are important Access to site, location of factories and availability of skilled labor are important considerations Factory production of modular bridges minimizes construction duration 538 CHAPTER 11  A Review of Chapters, River Bridges, and Conclusions Construction management plays the most important role in rapid construction and delivery The methods of ABC construction with design-build management are incremental launching, roll-in rollout, slide-in and float-in methods Facilities such as transporters /SPMTs, heavy lift cranes and equipment come next New sources of funding such as public-private partnership have made possible the funding of a variety of bridges The design of ABC bridges would require a separate code and specifications Both AASHTO and State design manuals need to be developed to be in conformity with the method and sequence of construction Training of engineers in ABC methods is required Emphasis should be on using innovative approach as each site is different 11.10 Conclusions The subject of modular bridges is still in its infancy, but it is developing gradually for highway bridges ABC was first used successfully in railway bridges, which has a narrow construction window Due to its success, it is now being extended to highway bridges ABC is a series of principles put into practice in a special way It is equally applicable to all types of bridges More than full ABC due to certain limitations, partial ABC applications, especially for superstructure replacement, is becoming more popular The reasons are as follows:   Multiple configurations and shapes: This is a specialized subject and each of the large variety of bridges is based on a structural configuration of beam, arch, truss, and cable (or the variations thereof) requiring a different theoretical and practical solution Thus far, steel and concrete beam bridges have received greater attention than other types Timber bridges, which can be used for smaller spans, can be more easily adapted to ABC For smaller spans, CON/ SPAN has come up with prefabricated concrete arches Investments in machinery: The transportation of prefabricated bridges requires specialized trucks like SPMTs, which are not readily available For lifting and erection of modular bridges, large-capacity cranes are required, which may not be available with small contractors   Luckily, the essential heavy equipment is being made available from the construction industry for refineries and for modular tall buildings Its use in industries other than bridge construction helps to keep down the huge costs of manufacture and maintenance of the construction equipment Renting or leasing is possible for the duration of the project Major shift in project management: The transformation from conventional project management of design-bid-build to design-build (or the CMGC system) has not been easy Most owners are used to the conventional system and are reluctant to switch over to the design-build system, due to fear of any mysteries involved or due to lack of experience with ABC There are only about 10 agencies with CMGC experience, including those in Utah, Florida, and Michigan   For smaller projects costing less, say about $25 million, there may be friction between the contractor and consultant’s teams The consultant usually considers himself the advisor and right-hand man of the owner He uses alternate structural solutions, but with ABC, the prime contractor has the upper hand in decision making There is far less time for research into alternate solutions, which the consultant prefers 11.10  Conclusions 539   O  n smaller jobs, these differences in perspectives may be resolved with the intervention of the owner The contractor tries to reduce the cost through value engineering, which helps the owner greatly It appears that the greater interaction between the contractor and consultant during an ABC project, with the primary aim of completing the project as fast as possible, helps the project’s objectives by arriving at optimum solutions Better communication can also increase quality and increase the contractor’s understanding of the goals of the project Lack of ABC codes and specifications: For these innovative practices, there are only a few design codes and specifications available New structural geometry resulting from hinge locations and erection loads need to be addressed A few states have developed interim provisions for selected types of bridges More work is required by other states and in particular by AASHTO The LRFD method of design remains unchanged Structural software for analysis such as SAP 2000 is still applicable For example, when using the lateral slide-in method, methods for calculating jacking forces and the sizes of diaphragms are needed Need for training: For safety reasons, there should be formal on-the-job training offered to engineers working on ABC projects so that the ABC projects are completed on time and without errors This training may be specific to the type of bridge to be built, whether on an entirely new route or a bridge replacement over an existing footprint Web-based training modules for owner policy issues and continuing education through seminars and workshops by FHWA, active states, and universities are important steps in the right direction Greater use of prefabricated deck slab: When deck slab segments are prefabricated and transported to the site for assembly, their assembly requires longitudinal joints The joints cause discontinuity and are subjected to impact loads and cracks from differential shrinkage Cast-inplace concrete decks not have these problems However, these joints can be filled up with cast-in-place UHPC, with compressive strengths exceeding 20 ksi   Prefabrication in a controlled environment would allow accurate longitudinal and transverse grades for drainage that are better than cast-in-place construction   Also, a topping layer made of latex-modified concrete or concrete with corrosion inhibitor aggregate may not be required, reducing the dead weights The top layers of rebar can be made of stainless steel rebar of high tensile strength, requiring a thinner concrete cover than ordinary rebas This also helps in reducing deck slab thickness and dead weight   Precast approach slabs can be constructed simultaneously with the deck Staging may be required to allow traffic flow at least in one direction With overnight work there should not be much holdup of traffic flow Construction while utilities remain intact: Progress in roll-in, roll-out and lateral slide-in methods has made it possible for existing utility pipes to remain in position undisturbed This leads to time savings and avoidance of the unnecessary costs of temporary relocation of utilities   During erection, the bottom of girders can be kept slightly higher than the top of pipes Temporary supports may be required for water pipes if necessary   Roll-in, roll-out is in one direction only using two temporary bents on either side of the bridge The slide-in method is not accompanied by slide-out if the previous bridge is demolished Jacking may be required for lateral slide-in For environmental reasons, debris needs to be collected and prevented from falling below 540 CHAPTER 11  A Review of Chapters, River Bridges, and Conclusions Need to make wider use of prefabricated abutments: The use of ABC has been rather limited for the substructure as compared to superstructure ABC use This is either due to less wear and tear of substructure compared to the superstructure or the difficulty in constructing the abutment while traffic is on the deck Substructure construction will be a lot easier for new bridges compared to replacement bridges   However, after demolition of the existing abutment, new prefabricated segments can be erected overnight or in one weekend In many cases, the existing substructure can be reused In other cases, staging may be required for maintaining limited traffic flow Prefabricated wall components that are commonly being used include MSE walls, T-walls, and georeinforced earth walls Wider use of prefabricated piers: For ABC construction, the use of precast pier caps and precast concrete columns constructed in segments is becoming popular The columns can be prestressed in the axial direction On a busy highway in New Jersey, the author used an innovative precast column construction approach by extending the precast round pile length by approximately 15 ft and elevating pile cap as precast pier cap The piles are designed to act as columns The system is stronger with fewer connections 10 Prefabricated footing slabs: Foundation costs may be higher than that of the superstructure or substructure components The problem with prefabricated footing slabs lies in transport with its tremendous weight, even when SPMTs are used Footing slabs may be over 5 ft deep, while precast deck slab is only about 9 in Hence, transportation on routes that have bridges with weight restriction will not be possible In such cases, footing slabs need to be cast next to the site and lifted into position with heavy cranes   For sign structures, prefabricated cantilever slabs are currently being used with ABC In some cases existing footing slabs can be reused and, if required, strengthened by driving minipiles However, if existing cantilever footing slab needs to be replaced, it is demolished, along with the abutment wall This would be necessary when the projections of the footing slab on either side of the abutment are large and are likely to interfere with the new footing slab   For existing deep foundations such as piles or drilled shafts, use of the existing grid layout may not be feasible, due to interference with old piles New piles need to be located a few feet away from the existing ones, to act as frictional piles only when sufficient soil media is available Sometimes bored and drilled piles may be necessary 11 Bridge in a Backpack: A revolutionary approach to construction by doing away with formwork for the deck is being promoted by laboratory testing at the University of Maine Carbon fiber– reinforced polymer (CFRP) is used for long spans, and steel tubes are erected at close spacing Composite deck is placed on top of the arches The initial cost and life cycle costs are lower than for the conventional slab-beam bridges 12 Infrastructure Report Card: The ASCE Report Card’s constructive criticism can form the basis of a blueprint for modernizing infrastructure with sustainable technology Much needed reconstruction and applying sustainable technology will provide more reliable and long-term solutions Modernized roads, bridges, and traffic systems can have a ripple effect on efficiency The shortage of funds can partly be overcome by the P3 method Banks may also cooperate in lending 11.10  Conclusions 541 13 S  egmental Concrete Construction: For long-span construction, prestressed box sections are added on both sides of the pier using cantilever post-tensioning of box sections There are specialist contractors like Figg Construction who specialize in launching using high-capacity cranes With the advancements in high-strength, lightweight concrete and high-capacity cranes, segmental construction has become very useful One of the latest examples is the Bahrain Ministry of Works Project, which is one of the largest projects of its kind 14 Construction schedules for ABC: Reduction in the duration of the construction schedule is the most important benefit of using ABC A comparison between conventional Design-bid-build and Design-build methods will show that both the methods use CPM but definitions of critical path activities may not be exactly the same The duration assigned in the construction schedule is shorter for Design-build and the majority of activities are listed as critical path activities On a given superstructure replacement project, a comparative study between conventional construction of the superstructure with the following ABC methods is required to appreciate the differences in construction time: • Identify the construction season and months in a given year for the allowable fieldwork window (for bridge sites that are subjected to extreme weather) • Identify activities on the critical path when using prefabrication and SPMT methods and with design-build management Compare the overall duration of construction with the design-bid-build method • Identify activities on the critical path when using the lateral slide-in method with temporary bents and design-build management Compare the overall duration of construction with the design-bid-build method   On a given substructure and superstructure replacement project, a comparative study between conventional construction of the substructure and superstructure with the following ABC methods is required to appreciate the differences in construction time: • Identify activities on the critical path when using prefabricated abutment wall components and precast pier columns and caps Can the new abutments be constructed prior to the demolition of old abutments? • Does the existing foundation need to be removed before constructing new foundations, if pile driving is required? 15 Study of contract clauses for ABC: A sample set of contract clauses between the owner and contractor involving successful implementation of prefabrication and SPMT, roll-in, roll-out, and lateral slide-in methods is required What incentives are given to the prime contractor and his team for completion in minimum time? What penalties exist for any delay? There is an old saying that “it is easier said than done.” An investigation is required before a major commitment is made There are instances where contractors become bankrupt when trying to meet a deadline or there are other unfeasible construction challenges 16 Need for new contract documents and special provisions in construction specifications: ABC requires changes in conventional construction documents such as bid tabs; estimates of quantities, costs, construction schedule; activities on the critical path; specifications; and special provisions A sample set of special provisions as approved by the owner for the prefabrication and SPMT method and lateral slide-in method is required to appreciate the responsibility and liabilities 542 CHAPTER 11  A Review of Chapters, River Bridges, and Conclusions 17 F  or bridges located on rivers, a survey of scour countermeasures that are being used nationwide was carried out A form was successfully developed to assist in the field assessment of scour at bridges Introducing more rapid inspections to identify deficient bridges by using remote sensors is emphasized 11.11  Future deployment of ABC ABC is a boon for restoring travel in the case of natural disasters Rapid construction helps in disaster management USA has a very large network of highways and bridges are occasionally subjected to extreme events Floods, breach of levees, tornados and earthquakes seem to hit some locations in the vast country Dozens of bridges get damaged and need to be replaced asap and communications need to be restored Each day that is lost adversely affects public comfort, commerce and industry The progress in switching over to ABC and PBES needs to be expedited and the work force trained and SPMTs and high capacity cranes made available ABC is comprised of many bridge movements during construction Examples are as follows:   • Transport on SPMT • Lifting • Launching • Floating • Pivoting • Skidding • Rolling • Sliding   It is always helpful to the users of highways if there is greater flexibility in the construction of highway structures to allow the designers to avoid construction joints and multiple bearings if possible One example is the use of integral abutment bridges The history of the design-build method for rapid delivery goes back to 1998 for TEA-21 The Federal Highway Act was initiated back in 1938, and a list of design-build projects completed is available with National Project Exchange Users Guide published in July 2013 Some projects are already addressed in the chapters of this book There are considerations of indirect costs, risk, safety, and minimizing environmental concerns compared to conventional construction Due to the many advantages of using ABC methods, such as avoiding detours during construction, agencies like FHWA and NCHRP have taken initiatives to provide technical information through Website resources Case studies of successfully completed projects have been provided by a number of states FHWA has held international conferences such as the one in Baltimore in March 2008 The proceedings discuss the state of the art and are helpful in the development of the subject A few universities are also holding regular seminars It is expected that the use of ABC methods will become more popular as more projects switch from conventional management to design-build Bridge owners have a major role to play in adopting 11.12  Literature review/acknowledgements 543 ABC, as they can provide incentives and encouragement to contractors to invest in the necessary equipment and training to minimize the delays in the delivery of bridges While superstructure replacement costs may be comparable to conventional construction (which requires much more time), complete bridge replacement costs with ABC may be higher than $500 per square foot of bridge deck area Of course, with the implementation of new technology with higher strength, the life cycle costs are lower Note: Appendices to 11 are provided at the end of the book for ready reference Appendix gives a Survey Form for Structural Countermeasures adopted by transportation agencies in the United States It was used to summarize the valuable experience gained by the U.S states in the use and application of countermeasures on river bridges during peak floods 11.12  Literature review/acknowledgements The chapters in the assigned sections to cover innovative construction methods, recent developments in ABC concepts and the use of modular bridges It will be noted that PBES, as an important requirement of ABC is a relatively new subject There is research in progress by many federal and state organizations and universities as outlined in the chapters Hence it is likely that some of the procedures and methodology for rapid bridge construction and delivery will change for the better The author’s own practical applications in bridge construction in the northeast of USA are reported here USA has a unique network of highways, which has promoted the use of SPMTs and helped in the development of the subject A great deal of publications on the development of the subject is reported by FHWA, AASHTO, NCHRP, TRB and many states and the universities such as FIU Even prefabricating companies such as Hi-Steel, Acrow and Jersey Precast etc have implemented the innovative ideas in an effective manner Their contributions cannot be ignored The bibliography lists a volume of references For each chapter, a vast number of references are given, with the sources of information mentioned Website links to important publications are presented However, those references which were inadvertently missed out in the literature review can be seen in the bibliography list Care will be taken to update any references if missed, in the next revision of the textbook The author is grateful to Mr Benjamin Beerman of FHWA and Professor Atorod Azizinamini of FIU for their tireless and ongoing work on promoting the use of ABC and for providing access to their publications The objectives of the book are to help teach the subject to the students and promote the use of ABC in the multi-billion dollar construction industry AASHTO and state regulations and those by FHWA etc are being updated after every few years, with further research in the developing subject of ABC ... Section A? ? ?A East abutment FIGURE 11. 3 Use of gabion mat between abutment walls 10.8'' Gabion mat 512 CHAPTER 11? ?? A Review of Chapters, River Bridges, and Conclusions 11. 6  Rapid repairs and replacement... available 496 CHAPTER 11? ?? A Review of Chapters, River Bridges, and Conclusions • Organizations such as FHWA (with their Every Day Counts Program and ABC Handbook), Transportation Research Board... underwater and in painting of corroded girders 508 CHAPTER 11? ?? A Review of Chapters, River Bridges, and Conclusions 11. 5.1  Scour analysis Codes and design guidelines: The following FHWA and AASHTO