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27 Case Examples As noted in Chapter 1, follow-up case examples were conducted to gather further details on individual state use and perceptions of using DTMs in construction. The case examples were executed by phone or internet interviews between the research team and selected DOTs. The DOTâs survey respondent was contacted to participate in the case example interview and was notified to invite individuals with direct experience with DTMs to participate in the conversa- tion. The semi-structured interviews followed the questions outlined in Appendix C but often drifted toward unique experiences in each state. Six states were selected as case examples on the basis of their survey responses. Five states were specifically targeted because of their extensive experience with DTMs and, thus, their ability to share lessons learned with other states. One state was selected on the basis of its e-construction and other innovative initiatives but limited use of DTMs in construction. This state would then be able to share reasons for limited use even in a culture of innovation. The following criteria were used to select the experienced case example states: â¢ Having 10 or more years of experience with DTMs, â¢ Having used DTMs on 100 or more projects, and â¢ Having executed a project with the DTM as part of the contract documents. The five states experienced with DTMs that were interviewed were Maine, Ohio, Oregon, Pennsylvania, and Utah. Despite using DTMs in a relatively limited capacity, Alabama was also interviewed because it is a leader in many technology initiatives. Thus, its feedback was impor- tant for understanding some of the barriers and limitations of the technology for continued adoption. Each agencyâs interviews are summarized in Table 2 and then detailed in the subsequent subchapters in three distinct sections: benefits/motivation, challenges, and lessons learned. 4.1 Alabama 4.1.1 Benefits/Motivation The Alabama Department of Transportation (ALDOT) is in its infancy in terms of using DTMs in construction. Its first pilot project was a large grade and drain project, with design finished in the summer of 2016 and construction letting in February 2017. The design, including the proposed DTM, was created in-house. In addition to including the proposed DTM as part of the contract documents, ALDOT used the construction contract to purchase surveying equipment for field staff. Training hours were included to aid DOT staff in verification of the contractorâs work. The contract documents included a special provision that was designed to introduce and guide the construction process into further use of the proposed DTM, but it also C H A P T E R 4
28 Practices for Construction-Ready Digital Terrain Models DOT Benefits Challenges Lessons Learned Alabama â¢ Calculating quantities â¢ Learning with contractors â¢ Federal aid to assist pilots â¢ Setting expectations with contractors â¢ Having sizable projects for equipment resource needs â¢ Communicate early with contractors â¢ Understand capability of contracting community Maine â¢ Quick grade checks â¢ Easy quantity comparisons with contractors â¢ Time efficiencies â¢ Software constantly changing â¢ Legal hurdles (e- signatures, stamps, plan set of record) â¢ Equipment budget â¢ Peer exchanges help share information with adjacent agencies and contractors they have in common. â¢ Formal training program and frequent updates keep staff ready â¢ E-Construction Implementation team would be beneficial Ohio â¢ Enabling stakeless surveying â¢ Time savings â¢ Cost savings â¢ Standardized workflows â¢ Supporting contractorsâ needs â¢ Stamping a digital model â¢ Designer concerns with liability â¢ Lack of appropriate training â¢ Lack of standard file formats â¢ Identify what information the contractor needs â¢ Have support from CADD and Mapping Servicesâtype team Oregon â¢ Inspectors found tools that supported their work â¢ Model not yet used as part of the contract documents â¢ Provide significant, early, statewide training effort â¢ Lower surveying costs â¢ Fewer claims and delays over quantities â¢ Quicker and more accurate payments â¢ Fully staff Engineering Technology Advancement Unit with IT, design, construction, surveying, and other end users for trial and support Pennsylvania â¢ Facilitates AMG â¢ No more âdouble workingâ the model â¢ Compressed construction schedules â¢ Getting quantity measurements with high accuracy during construction â¢ Have a standard specification for surveying practices and training requirements â¢ Have a group that conducts experimental tests of new technology Utah â¢ Supports contractor needs for AMG â¢ Efficient data transfer â¢ Facilitates other emerging technology (unmanned aircraft systems, fully automated machines) â¢ Leveraging existing software in the field â¢ Surveying equipment costs for field inspectors â¢ Alternative project delivery methods (CM/GC, DB) maximize benefits. â¢ Require contractors to provide rovers and training Table 2. Summary of case example interviews.
Case Examples 29 addressed the existing ground terrain model. Active construction is still underway on the pilot project. Contract pay quantities associated with the grade work continue to be verified through field survey before payment is issued. To date, the contractor and ALDOT personnel are aware of no contractor challenges to the as-designed DTM details. As-built information is another requirement of the special provision in place. ALDOTâs initial focus was on projects with large quantities of grade work, so that it, and its contracting community, could get the most benefit from using AMG. It hopes to conduct several more pilot efforts; however, there has not been a significant project with grade work in the state because of budget constraints. Much of ALDOTâs motivation for using DTMs in construction came from attendance at an FHWA EDC-3 Peer Exchange. The road construction engineer for ALDOTâs Construction Bureau attended the workshop on using 3D models in construction that was hosted by the New York State Department of Transportation (NYSDOT). The meeting provided confidence and information for ALDOT to begin its first pilot incorporating a special provision that could be included in the construction contract. Despite some issues with this first pilot project (noted in the next section on challenges), ALDOT is determined to continue. ALDOT realizes that contractors and other agencies are moving in this direction and that now is the time to gain some needed experience. 4.1.2 Challenges With the strategy of focusing on large-volume grading projects, one roadblock to further use of DTMs in construction is the lack of projects that fit that criterion. The strategy includes procuring equipment for agency inspectors and reimbursing contractors for their expenses in acquiring equipment. For financial reasons, however, ALDOT had to be selective about the size and type of projects for trial. Spending 5%â10% of a project budget on specialized equipment would not be feasible for a pilot effort. The pilot is still ongoing, but the first two years were particularly challenging. The project was intended to require the contractor and agency to survey daily with GPS and compare data for validation. The contractor, however, did not perform a daily survey for the project, believing that the special provision did not require that effort. The contractor hired a surveying firm to perform monthly surveys, but they were not frequent enough to cover installed work that got covered up before the next monthly survey. 4.1.3 Lesson Learned The design work was completed in-house, and a consultant is being used for inspection and the fieldwork related to DTM use. The designer of the DTM transitioned to a different office during the project, so he is not available for quick reference. ALDOT found that amending design consultant purchase orders to add the desired DTM deliverables for ongoing designs meant delay and cost that were prohibitive. It also indicated that the additional modeling effort during design may not be appropriate for smaller projects, such as bridge replacements. ALDOT leveraged several federal resources to help establish the pilot effort. As noted, an FHWA-sponsored peer exchange provided critical knowledge and references to get the project started. ALDOT also used FHWA funds through the State Transportation Innovation Council program to hire a consultant to aid with the specification development, to help acquire equipment, and to use in the project to support the effort.
30 Practices for Construction-Ready Digital Terrain Models The process of requiring the contractor to survey, with the agency following closely behind, would have been beneficial to validate the technology as well as to create an opportunity for informal learning. As contractor and agency staff collaborate to create models, they can assist in troubleshooting and sharing effective practices that they can bring back to their respective organizations. Early communication with the contractor could have improved project outcomes. Issues began at the pre-construction conference when the contractor did not plan to survey as the agency had expected. Despite some experience with AMG, the contractor did not have a signifi- cant amount, which may have caused some hesitation. In addition, the contracting community does not appear to use AMG for paving, so the primary benefits for stakeholders using DTMs in construction would still be large grading projects. 4.2 Maine 4.2.1 Benefits/Motivation Since 2002, the Maine Department of Transportation (MaineDOT) has held an interest in electronic layout and documentation tools. Much of that interest was piqued by advancements made in the contracting community. At about that time, AMG showed up in its projects, which forced the state to figure out the technology so it could properly inspect the work. If contractors were building with digital data, the state needed to be inspecting with digital data. As it learned more about the technology, MaineDOT began to see its value and the future of doing stakeless construction with AMG. The rollout in Maine was strategic. With a small state budget, convincing leadership of the required investment in the hardware and software was a significant request. To get around this challenge, Maine borrowed contractorsâ survey equipment and rented other equipment. Job assignments were spread out to areas where the contracting community was more techno- logically advanced and would be running AMG. Almost all of the stateâs contractors are now comfortable using AMG and other e-construction tools such as electronic bidding, electronic signatures, and new surveying technologies. MaineDOTâs construction staff members sit on various national and regional committees and participate in tri-state symposiums with New Hampshire and Vermont to learn about the newest technologies. With a smaller geographic footprint, the contracting communities in these northeast states are similar, so these information exchange platforms and shared policy visions are mutually beneficial to the DOTs. They have also seen the impact that one contractor can have on competition when adopting a useful technology. The most significant benefit for Maine has been the ability to track quantities, in particular earthwork volumes. The ability to take a GPS rover to various points of a project to check grade and detect deviations has resulted in huge time savings with improved data. Grade, centerline, cross-slopes, elevations, and other spatial information can be captured quickly, an outcome that presents a significant upgrade over stringline and grade stakes. The technology makes it easy for MaineDOT staff members to compare quantities to the contractorâs quantities. An additional benefit is the amount of surveying support throughout the state. The central office, located in Augusta, provides surveying for the entire state, but regional offices have their own personnel and equipment also. They are ready to help check measurements as available. Maine has one licensed surveyor in the central office as well as one in each of its five regional offices. Staffing levels are assisted by the technology because inspectors can be more efficient with their time while acquiring the same information previously collected. Further, maintenance gets more accurate location data on assets.
Case Examples 31 4.2.2 Challenges The current barrier to further DTM use is MaineDOTâs current effort to migrate to OpenRoads Designer (ORD). MaineDOT will have some growing pains adjusting to the differ- ences in the software, but it is still early in the process. Once the system is fully implemented, MaineDOT will have to verify that the 3D plan set meets its needs. Some other states that adopted ORD early had some issues when a software update occurred and caused inoperability issues with their standards. MaineDOT has a long-term plan to have the 3D model as part of the bid package but must get over some regulatory hurdles on electronic signatures and stamps and on defining what can be a plan set of record. Despite those current issues, the DOT has enough incentive and motivation to overcome them in the near future. Currently, MaineDOT runs its fieldwork off of the contractorâs base station and with contractor equipment or rented equipment. There will be a time when Maine needs to invest in its own equipment and base stations for independent confirmation. The state has a good Continuously Operating Reference Stations Network to survey from but needs its own tools to fully take advantage of that network. 4.2.3 Lesson Learned The agency began changing its training procedures about 8 to 10 years ago, which involved how to document inspection work electronically while staying within specifications from FHWA. There is no change in the documentation and information, only in how they are captured and presented. Thus, inspectors no longer use field books but now use FieldManager (an AASHTOWare product). Despite some pushback from inspectors in going away from their field books, personnel will adapt as the new system is used and expected more. As noted in the previous subsection, design is moving toward ORD, the most recent Bentley update merging InRoads and Microstation, and MaineDOT is hoping for strong interoperability with construction software like Trimble Business Center (the most-used software of Maine contractors.) Training focuses on how to use the technology, not necessarily on what infor- mation is being collected. This approach seeks to keep the traditional skill set of inspectors while blending in the new technology. Poor satellite connections in parts of the state have caused issues locating with base stations; inspectors can overcome technical problems by maintaining their knowledge of conventional methods. The training is deployed through a typical large meeting, with follow-up one-on-one training as needed. Often, the best way to train has been by field trial. Eventually, most inspectors gain an appreciation for the assistance that technology provides. Some experienced staff members can identify areas that need further checking; for instance, in one project an inspector could tell that measurements using rovers were off. Previous GPS points were in alignment, and no one could understand what the issue was. Eventually, someone figured out that a laborer shoveling snow off the roof of the contractorâs trailer was picking up the base station, not knowing what it was, to shovel the snow and then setting it back down. In this situation, old and new training paid off. The experienced inspector with training in traditional methods could tell the data from the rover were wrong. The inexperienced laborer made a critical error that could have caused significant problems and delay if not identified early. As more technology becomes available, field verification and calibration will be critical. But also, importantly, DOT staff still need to visually check and feel empowered to speak up. If the model and rover say a pipe is in the correct place, but one can see that it is not aligned with a stream, then something needs to be done. This is where traditional methods and fundamental training remain essential.
32 Practices for Construction-Ready Digital Terrain Models Another lesson learned was to take a similar number of location shots with the GPS rovers as the contractors do. In a project approximately 10 years ago, the contractor and MaineDOT had significant differences in quantities. After some conversations, they realized that the contractor took significantly more data points (in the range of 100 times more), which picked up detailed high and low points. The contractorâs surveyors knew to focus their data so that breaks in the terrain were captured. Once DOT personnel followed this method and increased their overall number of points collected, discrepancies were essentially eliminated. Now, the agency and contractor field staff walk the project together and take similar shots. Although the 2D plan set remains the legal set of record, MaineDOT routinely uses a contract modification to address the contractorâs preference for using the 3D model and stakeless surveying. DTM usage can also be a special provision in the contract. At one time, Maine paid plan quantities for yardage bid items. Variations in bidding seemed to indicate that some contractors were exploiting this provision, adjusting their bids through independently performed quantity takeoffs. The state moved to in-place quantity payments in an effort to remove this perception of risk by the contractors. The surveying technology helps facilitate that transition as well. About a year ago, Maineâs Division Directors began holding quarterly meetings to discuss the technology that might aid their asset management responsibilities. DTMs and associated digital information are seen as a cross-divisional subject. Their quarterly meetings are parti- cularly beneficial in exposing various DOT staff members to a range of potential benefits of new available technologies. For example, Maine is distinctly multi-modal, and the DOTâs responsibilities for ferry operation are seen as another area in which DTMs might be an efficient tool for asset management. Finally, a small team that oversees e-construction implementation across all divisions in the agency would help maximize success. Such a group does not currently exist, but construction personnel see the benefit that troubleshooting technologies and addressing policy roadblocks early would have. 4.3 Ohio 4.3.1 Benefits/Motivation Construction staff members and the agencyâs contractors pulled the Ohio Department of Transportation (Ohio DOT) into a digital world where DTMs of existing and proposed surfaces are created and shared. Ohio DOT CAD standards have required electronic engineer- ing data as a product of the design phase for some time, but the information was not shared until contractors began requesting it. The stateâs contractors use the models for estimating quantities, bidding, and machine guidance. A multitude of useful and critical data exist for the construction field. There is more effort in design, which Ohio DOT believes is well offset by the benefits in construction. Benefits are wide ranging and are anecdotally noted by Ohio DOT. The primary benefits include cost savings, time efficiencies, data consistency, and improved accuracies. Having machine control perform grading tasks saves on surveying, staking, and labor hours involved in grade staking. If contractors can prove the accuracy of their surveying tools and the com- petency of field staff operators, Ohio DOT permits stakeless surveying practices. The standards, specifications, file formats, and other policies can help provide some consistency in information workflows. In addition, Ohio DOTâs Office of CADD and Mapping Services provides a wide range of support services to facilitate effective use of digital design and construction informa- tion. It developed a standardized workflow to get design files and digital information efficiently
Case Examples 33 to contractors during the letting. The previous process required a request of information; now it is standard practice to automatically provide the information. A pilot project was conducted in which a design consultant modeled grading for earthwork on a project and included it as part of the contract. The project modeling was originally done in Geopak and was later converted to Bentley ORD. Areas of the model that existed but had not been fully developed as part of the grade design were blocked out. In those areas, the proposed model was not contractually binding (for reference only) and could be readily identified by the contractor. The pilot had no significant issues, but its design and quantities were not compli- cated or significant. Ohio DOT is still capturing feedback from the contractor and has other administration processes (i.e., stamping a 3D model and handling field changes in the model) that need review and approval before it can continue moving the effort forward to get a model in the contract. Ultimately, construction needs pulled the agency forward; if contractors push for something, it likely has a cost savings or time savingsâor both. Ohio DOT expects to implement varying degrees of required complexity within the proposed model information, related to project scope or type. Its inspectors have access to an app that uses location and roadway alignment data for logging photographs. Inspectors also have laptops. Ohio DOT has engaged Bentley to discuss potential tools for inspectors who use the 3D model. 4.3.2 Challenges While Ohio progresses forward with digital project delivery, it still has several issues to sort out, including stamping a proposed model and designersâ concerns with liability. One of the major gaps is in appropriate training and skill development for Ohio DOT staff. Ohio DOT has not conducted formal training focused on reviewing the proposed models delivered from design consultants. Conflicting details occur between the paper plan sets and the electronic engineering data. The agency relies on individual, informal peer training on the equipment and model transfer, primarily because it has resource constraints from both a cost and a time perspective. The previously mentioned CADD and Mapping Services group can assist as needed, but it is not set up for formal training for construction staff. Ohio DOT hopes to improve con- sistency of the field verification of the proposed model information against sitework. Because the model is not yet part of the contract and contractors use different software than designers do, it is still up to contractors to manage file formatting issues to develop their own proposed model correctly. Ohio DOT has found that contractors often digitize the PDF plan set information they receive. Ohio DOT notes a variety of other challenges, including having file formats and informa- tion needs that are accessible for all project stakeholders; having appropriate skills, equipment, and time to do model verification; rapidly changing mobile device technology; file sizes and file management; connectivity; and modifying daily site inspection practices to include a digital workflow. Ohio DOT is additionally dealing with low staffing levels and a workforce that has little time for training. 4.3.3 Lesson Learned On the basis of previous technology implementation, Ohio DOT learned to let construction drive what designers do instead of pushing information out to construction. Ohio DOT is in the process of gathering feedback from its construction personnel and contractors about how they consume the data (e.g., how they use proposed models, what level of detail is neces- sary in the model, and what features need to be modeled). This information, in combination
34 Practices for Construction-Ready Digital Terrain Models with some of the workflow challenges noted previously, will help facilitate further use of 3D in construction. This effort is ongoing and in conjunction with the stateâs contractor association. In addition, the CADD and Mapping Services team has a wiki page with training information and a surveying guide. It also has a monthly webinar to help keep its staff members informed. 4.4 Oregon 4.4.1 Benefits/Motivation Oregon DOT (ODOT) started its DTM journey in 2011 with a 3D roadway design committee comprising in-house and consultant designers, but the committee had limited construction representation. This committeeâs objective was to transition all design projects to 3D models as one of the design deliverables. It took almost 5 years to establish, implement, and change contracts to accomplish that objective. In 2015, ODOT began requiring a 3D design model as one of its design deliverables while still having paper plans and typical deliverables for construc- tion (DGN and XML formatted files). ODOT did not share the 3D models with contractors for AMG until 2015. Thus, the 3D initiative was successful until the project got to construction, because there was no construction involvement or a plan for transition to the field. Eventually, contractors were frustrated by still having to stake and survey, and resident engineers received that message. The state then began formulating plans to share models with contractors so that they could run AMG. Most contractors were building models from paper plans and cross-sections before sharing. The needed change was to allow the contractorsâ AMG work to replace traditional survey staking. The construction specifications were modified in 2016 to reduce staking when AMG is being used, but ODOT still did not have a good way to check the work in the engineer offices. Many early challenges included the following: Most construction offices did not have the surveying tools and equipment for inspection; there was very little CADD or 3D design knowledge in the construction offices; the state was concerned that, without the proper tools or training, the models would be useless for its construction staff. Further, ODOT needed to be sure it had sufficient time and resources to get its construction personnel up to speed. The first effort was providing inspectors with GPS tools to use on their projects. It began as a pilot effort in three regional construction offices that could mobilize quickly. The inspectors received two 8-hour basic trainings on opening files, checking the model, using the equipment, and so on. Centralized surveying support was provided, and group emails helped keep everyone up to date while the modernization effort was under way. Then, over the course of the next 2 years, procedures, construction workflows, and other policy changes were made to enable field use of DTMs. The changes included changing forms, adding and modifying specifications, and providing guidance on inspectorsâ diaries. ODOT encountered roadblocks along the way, but a bottom-up approach allowed end users to assist in rapidly addressing issues and to guide the methodology to suit their needs. Around 2018, the goal of equipping every construction office with hardware, software, and personnel training was achieved. Oregonâs centralized technology group maintains a high profile, offering training and communicating at construction inspector seminars. The model workflow has been enabled from design through construction project close and final payments for all projects. ODOTâs inspection staff members were highly receptive to the changes. Experienced inspectors found that the new tools supported the high-quality work they were already doing. Contractors are significant beneficiaries of the changes as well. At bid, 80% or better models are issued, which reduces their estimating risks. After bid, 99% complete models lower surveying costs through AMG. In general, contractors more consistently achieve their smoothness bonuses. One project
Case Examples 35 saw a 30% schedule savings through model use. Contractors that were early adopters had a competitive edge because of the efficiencies gained, which also put added pressure on the competition and hastened ODOTâs move toward digital delivery. The state also benefits from reduced claims and arguments over quantities, and leaders believe it is because they can verify plan quantity bid payments. The 3D models, AMG, and global navigation satellite system (GNSS) tools have reduced the variance in what the contractor calculates, what the agency calculates, and what the plan quantity/bid item states. Now everyone gets the same answer because everyone is using the same data. With faster, field-verified quantity measurements, payments occur more quickly and accurately. The model workflow also creates transparency between the DOT and the contracting community. DOT construction staff have enjoyed additional benefits from the innovation occurring in their field offices. Going from flip phones and adding machines to GPS and digital plans raised abilities, skills, and, significantly, staff morale. 4.4.2 Challenges The last major step for ODOT toward fully digital project delivery is mandating the use of DTMs and 3D models by adding them as part of the contract documents. Although models are created and shared for every project with significant earthwork, adding them to the contract documents with precedence over plans would be a logical next step. The eBIDS handoff pack- age and construction survey handoff package are required on all state and federal aid Statewide Trans portation Improvement Program roadway projects designated to 3R or 4R standards. This requirement applies to projects located on the state highway system, regardless of whether the project is delivered by ODOT, a local agency, or a consultant. Any exception to this requirement must have written approval from the region roadway manager no later than the Advance Plans project delivery milestone, as described in the Highway Design Manual. ODOT inspectors rely, however, on the model as a field verification tool during inspection, so it makes sense that there is not a current push for adding the model to the contract at this time. The model already holds a secure role in supporting contract management and oversight efforts. 4.4.3 Lesson Learned Without skilled field staff, the process would have significant challenges and inefficiencies that could doom the effort. Thus, one of ODOTâs first noteworthy initiatives was to provide training at construction offices, which was a major undertaking. After the local pilots, training was conducted at every construction office. To even access the hardware, an 8-hour training course was required. Regional training was then offered on an as-needed basis or as updates occurred with hardware and software. In addition, at any training session for inspectors or any other formal meeting, quick updates were provided while also allowing for the inspection staff members to provide feedback. Contractors are required to share any digital informa- tion they intend to put to use on a project. The concept of sharing information frequently helped keep lines of communication open and reinforced the importance of using these tools effectively. ODOT also staffs an Engineering Technology Advancement Unit with individuals from IT, design, construction, surveying, and other end users of engineering technology. These individuals are tasked with identifying emerging technologies, evaluating their feasibility for use, and assisting in implementation and training. Thus, as issues arose, ODOT operations personnel had access to the Engineering Technology Advancement Unit to help troubleshoot solutions, and they then distributed their new knowledge throughout the state.
36 Practices for Construction-Ready Digital Terrain Models 4.5 Pennsylvania 4.5.1 Benefits/Motivation The Pennsylvania Department of Transportation (PennDOT) has an agencywide goal to go completely digital by 2025 through all phases of a project. The initiative, Digital Delivery 2025, envisions that construction projects will be bid using 3D technology and will no longer be in a traditional plan format. Some projects are exempt, such as guide rail, pavement marking, crack sealing, and bridge preservation. Although recently unveiling this initiative, the agency has been using 3D information since the mid-1990s with surveying and photogrammetry. The initial significant transition was for designers who could visualize and understand 3D survey data but had always produced 2D plan sheets as their product. Thus, they were not completely comfortable sharing models with contractors. Contractors received only 2D plans (in PDF); they would then survey, occasionally use LiDAR, create their own models, and use AMG to build. PennDOT personnel refer to this cycle as âdouble workingââwhen the 3D design model is discarded and then recreated. Starting in 2013, districts and design consultants were allowed to share 3D models for information only. Digital Delivery 2025 will ultimately produce complete models for contractors. Designer training is under way and nearing completion. The biggest driver for PennDOTâs use of DTMs is AMG. Using machine guidance offers significant time and cost savings, workflow efficiencies, and improved accuracies. The stateâs contractors have used AMG and 3D models for so long that it is difficult for them to remember managing projects without those resources. By moving to this technology early and with the ambitious goals for 2025, the state actively investigates new technologies. It was an early tester of terrestrial and mobile LiDAR as well as unmanned aerial systems (UASs). Having the resources and willingness to try emerging technologies gives PennDOT an advantage of effectively leverag- ing new tools and technology earlier to capture better data more quickly. 4.5.2 Challenges One initial challenge for PennDOT was the lack of available time in the construction phase of projects for its personnel to become familiar with the surveying technology. PennDOTâs surveying experts had early involvement with design staff through ground surveys, photogrammetry, LiDAR, and other products used in design. Their involvement gave them time and familiarity needed to build confidence in the technology. When construction needs survey information, it is often a critical item, but the in-house surveying group is not set up for quick turnaround. Quantity measurements are still a challenge for PennDOT. Its surveying office has experi- mented with UASs and other reality modeling technologies to create a DTM to represent inter- mediate construction conditions. These solutions are not ideal for serious design applications; however, they are able to get quick data on quantities and changes in earthwork. Pennsylvania currently has a steering committee and pilot efforts to use UASs for quantity measurement. During the current coronavirus pandemic (spring 2020), the UASs have been useful as a social distancing tool for construction inspection. The ultimate goal would be to verify payments to contractors with these quantities using a DTM, because contractors are still traditionally paid by truck load. 4.5.3 Lessons Learned PennDOTâs construction specifications are issued through Publication 408. Section 686 of this publication outlines construction surveying procedures and refers to processes for
Case Examples 37 surveying with AMG. It includes a provision that inspectors and field staff should receive 2 days (8 hours each) of training on the equipment, tying into benchmarks, loading the models, and using models for AMG; the training includes a Q&A session. The inspectors and field staff receive a second 1-day, 8-hour training refresher for every additional year that equipment is in use. One additional lesson learned noted by PennDOT relates to its surveying technology experi- mental tests. When a new technology has the potential for use in the state, a ground truth exercise is conducted (location of 5â20 points compared to traditional survey points). The results of this test are used to guarantee repeatable results to give confidence in the technology itself. 4.6 Utah 4.6.1 Benefits/Motivation The culture in the Utah DOT (UDOT) has resulted in an innovative attitude best described as ânot being afraid to fail in the interest of trying things out.â UDOT has had continuous administrative leadership for 20 years, resulting in a consistent message and shared vision for experimenting with and using technology. There is no roadblock of having to prove ROI for emerging technologies; rather, there is a trust within the DOT to explore and make appropriate decisions on potential use. UDOTâs journey with DTMs began with AMG for paving and earthwork. It was a contractor- driven effort, because contractors came to the agency describing a need to build models to run the new equipment. The close, trusting relationship between the agency and its contractors facilitated this request, so UDOT had little hesitation sharing the design model with contrac- tors. Partnering has also been an intentional and integral part of UDOTâs culture. The strong relationship between the agency and the contracting community allows for technology trials. The culture of innovation stirred up some thoughts within UDOT, which began to investigate putting the models in the contract, working toward fully digital project delivery, and getting rid of paper documentation altogether. The vision to go digital led to a standard way of thinking when evaluating current procedures and a realization that many processes involved capturing original information, stripping it of certain data, and then, at best, sharing what was left for another party to rebuildâwhich is inefficient, redundant, and costly. This initiative was assisted by a robust DB program in the state that fortuitously began decades ago. In 1990, Utahns decided to strongly pursue a bid for the Winter Olympic Games and approved tax revenues to support construction of the necessary infrastructure. They hoped to land the 1998 or 2002 Winter Olympic Games, so this infrastructure was needed quickly. Utah state legislators drafted and signed legislation allowing for the DB delivery method to facilitate the compressed timeline. Thus, UDOT has many years of experience with DB that bridges the gap between design and construction and helps build collaboration and confidence in the DTM tools and technology. The traditional design-bid-build delivery method may lead to some hesitation by contractors to use a model provided for information only. Although DB enabled the early, rapid adoption of DTMs in construction, the first projects that used 3D design in construction were CM/GC arrangements. The CM/GC process gives an opportunity for risk to be discussed early with contractors. These alternative project delivery methods brought designers, contractors, and the DOT together early in the projects to discuss the specific model-based needs of the contractors. Such methods put an additional workload on designers to develop more complete designs that donât leave much for contractors to decipher, but any increase in engineering/design hours is easily offset by earlier clash detection of typical field issues. UDOT has seen a dramatic decrease in contractor claims along with the intrinsic
38 Practices for Construction-Ready Digital Terrain Models benefit of having contractors understand what goes into project design and the design process. A shared, mutual understanding of the work involved helps both parties gain an appreciation and collaborative attitude toward project delivery. Because the design estimator and construc- tion superintendent need different information from the digital design, post-construction debriefings are beneficial and should be done as early as possible. Specific benefits seen by UDOT include the efficiency in data transfer with AMG and building confidence in design that facilitates model use in asset management. A comprehensive model is critical to UDOTâs long-term goal of moving away from paper documentation and toward digital information. Further, the agency can position itself to take advantage of emerging technologies such as UASs and fully automated machines only if a DTM and 3D design are ready. Not only does the technology need to be proven and ready but the human skills also need to be developed and prepared. Moving construction and asset management tasks to model- based processes pushes the technology into the hands of employees and away from traditional paper documentation. 4.6.2 Challenges An issue for UDOT has been leveraging existing software packages for maximum benefit in the field. The design software packages are fantastic for the design phase of projects, but the models are difficult to consume in the field without laptops and the relevant software package. The field viewer tools need improvement. As DOTs run into software concerns, it would be beneficial to document and share those with service providers, given the market share that DOTs represent. To avoid these issues, where possible, UDOT still uses 2D data through Esri and geographic information system software. A software-agnostic approach is needed to meet the demands and requirements of DOT work. Surveying equipment for inspectors is expensive, so a low-cost solution would enable increased use. It will also be important for attracting future generations to work for the DOT. New technologies such as UASs, DTMs, and AMG provide more sophistication to the roles and responsibilities of field staff. 4.6.3 Lesson Learned UDOT stopped doing its own surveying about 20 years ago (for design and construction) and placed those responsibilities with contractors. In the process, the agency lost an immense amount of surveying knowledge. With the capabilities afforded through DTMs, construc- tion and inspection staff need to develop those surveying skills again. The leap in surveying skills for inspectors from plans to models is significant, so states that do most of their own surveying may have an advantage from a knowledge and skills standpoint. A contractor intending to use AMG must provide GPS rover(s) for inspection and training on the chosen proprietary system, whether itâs Trimble, Topcon, or another provider. Data collected by the survey are sent to the designers, who verify that the shots in the field match the model. The verification process is not critical, however, because inspectors still take core samples, measure thicknesses, require smoothness, and take other QA steps. Contracting method plays a huge part in facilitating workflows with DTMs. CM/GC, DB, and progressive DB all present advantages by promoting a stronger relationship between the designer and contractor. The traditional contractual relationships in design-bid-build can inter- fere with their dialogue and sharing of information.