Design-build project delivery is one of the most significant trends in U.S. design and construction today. Used for more than 40 percent of non-residential construction projects, according to the Design-Build Institute of America, the single-source contract approach accelerates projects and saves money through innovation.
Design-build gets its speed from the builder and engineer working collaboratively to deliver the design and then construct it. And, yet, within this highly synergistic relationship, there can be a serious disconnect when the builder must translate the engineer's 2D paper designs into 3D models.
More and more construction equipment is operated by automated machine guidance (AMG) systems, which incorporate the use of 3D computer models to precisely direct the operation of the machine, improving the speed, accuracy, and efficiency of the transportation construction process. Many contractors now rely on AMG as an everyday tool for grading, paving, and staking.
As civil engineers transition to 3D, many find themselves producing two sets of deliverables: 3D model electronic data for contractors and traditional 2D paper plans for project owners. For decades, engineering teams only had to check those paper plans against design intent. Now, they must compare their 2D plans with the design intent, the 3D model with design intent, and the 2D plan with the 3D model.
The task of ensuring every detail is carried forward from iteration to iteration is time-consuming and fraught with risk. During conversions, information can be misinterpreted or unintentionally left out. Thus, to ensure quality throughout the project, engineers must change the way they compare and validate their work.
Quality assurance in design-build and other alternative delivery mechanisms is the focus of HNTB Corporation. One of the firm's latest innovations is a firm-wide design-build quality plan for ensuring the quality of the deliverables in a 3D project. With the plan, we are evolving HNTB's existing QA/QC process so it better aligns with the aggressive schedule and 3D deliverables associated with alternative delivery projects such as design-build.
To add value, a new QA/QC process has to allow us to:
- quickly combine data from multiple sources;
- conduct staff reviews from multiple locations;
- capture results in a managed environment; and
- respond in a timely manner.
To meet those requirements, we infused HNTB's existing quality management process with a suite of Bentley Systems products. Bentley was selected because it best met project staff skillsets and client/owner deliverable requirements. Using the following Bentley tools, we now can generate or validate 3D models:
- For data source, we use MicroStation, which displays in a single location all the data from InRoads, InRoads Storm & Sanitary, AutoCAD, internal HNTB applications, and other sources.
- For storing data, we use ProjectWise, which gives our subject matter experts in 60 offices nationwide quick access to project data in a secure, manageable environment.
- For conflict resolution, we incorporated Navigator's clash detection functionality. After the data has been displayed in MicroStation and saved as a read-only i-model, we use this new software to identify conflicts and document resolution early in the project life cycle.
- For comparing design versus plan, we use Dynamic Plot to reduce review cycle times and assure markups are captured in a managed environment.
- For 4D phasing plans, we use Navigator, again, because it provides owners with visual proof that a construction phasing plan will work.
Our new design-build quality management process significantly reduces review time, identifies and allows resolution of conflicts much earlier in the project life cycle, and in turn, dramatically reduces the number of in-field conflicts that can protract schedules.
We chose to test the new quality management process on one of the largest design-build projects in the history of the Virginia Department of Transportation (VDOT): the $1 billion I-95 Express Lanes. The project encompasses 29 miles along I-395 and I-95 and is designed to connect with another VDOT mega project, the 495 Express Lanes (Capital Beltway).
HNTB is lead engineer on three of the four I-95 Express Lane project segments. Our responsibility covers 20 miles and nearly $400 million in construction. Our work included:
- converting HOV lanes to congestion pricing/tolling;
- maintaining existing electronic high-occupancy vehicle systems and gates;
- two new flyover bridges;
- two bridge widenings;
- 40 miles of sound walls;
- 26 gantries;
- 96 overhead sign structures;
- 137 intelligent transportation system poles;
- 112 cameras; and
- miles of conduit.
With the new design-build quality management process, we were able to:
Identify and document conflicts during 100-percent design – We loaded all discipline-specific designs (roadway and grading elements; proposed and existing drainage elements; existing utilities; existing and proposed conduit; proposed signing, lighting, and gantries; cameras; proposed bridges; and retaining and sound walls) into the Navigator model. Within five minutes, the software identified more than 500 conflicts. Within a day, we had estimated conflict severities and were addressing them one by one.
We possibly would have identified some of those conflicts using the traditional review process, but we would not as easily documented who was responsible for resolution and how they achieved it. That's where Navigator really delivered value. Before, we had no process for auditing design-build plans. VDOT and Fluor-Lane have conducted several audits, and each one has gone well. Like anything else, we still have corrective action plans, but they have been minor.
Shorten the 100-day VDOT review and validation time to 74 days – 3D modeling reduced the number of packages from 196 discipline-specific packages on the Capital Beltway project to just over 30 integrated packages on the I-95 Express Lanes. Even though there were fewer packages to review, each package contained more information. However, by supplementing standard quality control procedures with Navigator, we were able to give VDOT a clear picture of data located in the field. Reviewers knew exactly what they were looking at. As a result, they were more confident that the design accommodated all the various pieces and met contract requirements.
Dramatically reduce rework – We received as many as 75 percent fewer comments per package than on the Capital Beltway Project. While difficult to quantify between project types, when we compared comments per sheet and field changes per dollar of construction, we found we had reduced comments by 50 percent and field changes by more than 60 percent.
Insights from the pilot
With all three segments now in construction and at or ahead of schedule, we are in a good position to step back and begin to critique the QA/QC process' performance while it is fresh in our minds. Following are some of our notes on what has worked and what needs tweaking:
- The process increased internal collaboration among department engineers, and it increased external collaboration among the owner, contractor, P3 concessionaire, and subconsultants.
- Informing the builder and owner of potential conflicts during plan production and resolving those conflicts before they happened increased confidences in the product being built.
- Having the right team doing the right things at the right time was key. For example, you might have the right team, but if team members don't have enough notice of when the reviews are supposed to happen, they will be busy on other projects and the QA/QC system will collapse.
- Communication among team members was vital. We held weekly task meetings with each discipline and kept the QA/QC process top of mind at those meetings.
- We designated a sponsor for each design package. Each sponsor was responsible for shepherding his or her package through the quality control process.
- The QA/QC budget and schedule was not an afterthought; it was built into the overall project from the start.
- In the future, having learned from the pilot, we would streamline review comments, perhaps using Microsoft SharePoint or a web-based dashboard. For this project, we used a Dashport site to capture comments, which allowed VODT reviewers to post and resolve their comments "live." This change resulted in faster closed comments as multiple people could read and resolve an issue at the same time. It also minimized any error in document control and likely reduced time by keeping one "master" set of comments, rather than compiling multiple sheets from multiple reviewers.
- For future projects, we would explore internal interdisciplinary, technical, and constructability reviews using digital pen technology. Because of the many markups during peer reviews, it may have been more efficient to capture them on one sheet.
Design-build is going to become more popular as owners are pressured to deliver urban congestion relief on constrained budgets. And, as adoption grows, 3D modeling will be the inevitable future of most civil engineers. With the transition to 3D modeling, HNTB anticipates 3D quality assurance systems will become a required specification, as well as a hallmark of a qualified design-build partner and trusted adviser.
Mo Harmon is vice president at HNTB, where he focuses on technologies and processes associated with delivery of design-build projects. He has participated on and chaired the Intergraph Civil Steering committee, served as a member of the NCHRP-TransXML project, and has published an article in the TRB Journal (EAS-E). He can be contacted at firstname.lastname@example.org.
Mark Lemieux is senior design application specialist at HNTB Corporation. He has developed innovative workflows primarily using GEOPAK and InRoads design software and has promoted and trained HNTB engineers across the country on the resulting concepts. He can be contacted at email@example.com.
Matt Simon is senior project manager for HNTB Corporation. He has more than 23 years of experience on complex freeway designs delivered via design-bid-build, design-build, P3s, and construction manager/general contractor. Projects range from low-cost improvements to multimillion dollar construction. He focuses on using technologies to enhance HNTB's design and quality management processes. He can be contacted at firstname.lastname@example.org.