Category: Bridge Design

From Desk to Harness: The SPRAT Certification Process for Bridge Inspection

Ben Schorn hanging underneath a bridge after earning his SPRAT Certification for Bridge Inspections

In 2021, I became a SPRAT-certified bridge inspector to enhance and expand my skills as a bridge engineer. The certification process was short but intense, and I’ll be using the skills I learned from this training throughout my career.

The Certification Process

The SPRAT (Society of Professional Rope Access Technicians) certification training was administered over the course of one week in which students were taught both behind a desk and in hands-on application. Critical information and theory in the classroom and physical rope access methods and techniques in the training facility. There was a diverse group of students in the class which varied from professional engineers to tradespeople.

Why I Got Certified

I wanted to become SPRAT certified because it seemed like a great opportunity to combine my passion for learning new skills (both physical and intellectual) with my thrill-seeking personality. I love being a student, regardless of the setting, so when I was offered this opportunity from Hoyle Tanner to take this course, I hopped on it immediately.

Training on Location

The certification course took place in a training facility in Oakland, New Jersey, which is about five hours from the Burlington, Vermont office where I work. The facility is basically a warehouse comprised of multiple stations varying in size and complexity meant to mimic common in-the-field scenarios where SPRAT skills would be used. There was also an air-conditioned classroom within the warehouse where we sat for lectures and took our written exams. Structural Engineer Katie Welch and I took this course in the middle of July so the warehouse was extremely hot (especially with full face-coverings while climbing).

Physical Intensity & Duration

Even though some of my coworkers who were already SPRAT certified gave me some insight to the physical intensity of the training, I was not prepared for the constant fatigue the training would subject us to. We spent many days practicing specific rope access techniques and procedures repeatedly, which to me was the most intense five consecutive days of exercise I’ve encountered in a very long time (that is, until I applied these skills while inspecting the Augusta Memorial Bridge in October 2021).

The course consisted of four days of instruction and one day of evaluation. At the end, everyone in our class received their SPRAT certifications and we were all very proud of one another for overcoming the physical and mental challenges the course put us through.

Engineering After Certification

Following the SPRAT training, I attended a two-week course in Chicago at the end of August which granted me a NBIS (National Bridge Inspection Standards) certification. These two certifications often coincide with one another, as the SPRAT certification is required to physically climb a structure and the NBIS certification is required to inspect/document deficiencies on a structure. With these trainings under my belt, I was able to properly participate in the inspection of the Augusta Memorial Bridge for MaineDOT at the beginning of October along with my colleagues Ed Weingartner, Joe Ripley, Katie Welch and Brian Nichols. It was very rewarding putting my skills to use and working together as a team to get this inspection done thoroughly and efficiently.

Is it Worth it?

The training required to receive a SPRAT certification is certainly a rigorous one, but it’s extremely rewarding overcoming the challenge. I would recommend it to anyone who’s interested in pushing their limits and learning new hands-on skills. I very much enjoyed putting my certification to use during the Augusta Memorial Bridge inspection last October and look forward to using my certification more in the future.

The Journey of Becoming an Engineer – 7 Years In

Ryan McMullen corporate headshot with bridge in the background and text that says "Journey of Becoming an Engineer"

Breaking Ground

The first few years of a career in engineering go by very quickly and can be overwhelming. On construction sites, you try and ensure that everything is being built per the plans and specifications and answer the questions of the contractor. This results in a lot of calls back to the office to get answers and confirmation. I remember the first time a contractor asked me if it was okay to make a slight change to the design to make things easier on their end. I didn’t know what went into the design and reasoning behind the design, so I could not give an answer without calling back to the office. When in the office, you are tying to get familiar with multiple design codes that are always getting updated and changed, learning how to design, learning what goes into developing a plan set or cost estimating, so you’re constantly asking questions. A lot of this requires engineering judgement, which can be frustrating because at this stage in your career, that is not something you have. Throughout this time, you are gaining an understanding of how things get built and what goes into it. It is a whirlwind of uncertainty while you constantly try to figure out the right way to go about things how things are supposed to be done.

Getting your Bearings

After a few years, you start to gain some traction in what you are doing. Those calls back to the office when you are on construction sites become much less frequent. You know where to find a lot of the information you need without asking for as much guidance and start to notice some of the differences in the design codes when they are updated. You are beginning to grow an arsenal of past projects you worked on that you can draw from and start to take on more responsibility.

I remember when a younger engineer asked me a question on how to perform a certain design calculation, and I was able to provide the reference in the code and an example calculation that I had done on a previous project. I was pleasantly surprised with myself after the young engineer successfully walked away with all the information they needed, with a clear understanding of how to proceed, and no additional questions. As your experience grows, so does your involvement on each project you work on. Then it is time for the next big step, studying for the Principles and Practice of Engineering (PE) exam. Before you know it, you are a licensed Professional Engineer with a stamp.

On your way to Substantial Completion

Looking around, you may not feel like you are at the level of those around you who have been stamping plan sets for years, but you are starting to make progress and have more confidence. That time spent in the field on construction sites is now coming in handy when designing by knowing what the contractor had difficulty doing and what went wrong. Your understanding of the full process of design and pulling plans together has you looking ahead and taking charge of what needs to be done to meet the overall goals of the project. You are more aware of the bigger picture of the project instead of focused on the individual task that you were assigned. You begin to give input based on the experience you gained opposed to always deferring to those with more experience. All this time, you continue to gain confidence. It all goes by so fast that being asked to write a blog about your first seven years of experience as an engineer is what it finally takes to get you to realize just how far you have come.

Jacks: Not Just a Kid’s Game?

Photo of A-jacks laid out on ground

Streambed scour is defined as fluctuation in the vertical position of a streambed, or the depth of the stream, as material is eroded and/or degrades. Some degree of streambed fluctuation is a natural process within the types of gravel-bedded rivers that we see; however, scour can also occur as a result of a change in the natural streambed conditions. Hoyle Tanner is currently assisting the New Hampshire Department of Transportation (NHDOT) with providing scour stabilization measures using an innovative system: A-jacks.

The History of Stream Crossing Design – If Only we Knew Then What we Know Now!

When the initial network of roads and highways was developed in New Hampshire, there was a different thought process towards designing infrastructure such as bridges, culverts or pipes, that crosses rivers and streams than there is today. Currently we would examine a stream from all angles to determine how to best approach designing a stream crossing that will not change the stream’s natural flow, depth or substrate (riverbed material). Stream crossing designs in the 1970s did not prioritize this stream information, and, as a result, in some situations the crossing structure has changed the stream’s parameters such as width, depth and flow.

The Results: Scour Pools & Stream Channel Changes

The most common example of this is where a stream crossing is too small to meet the stream’s bankfull width, or the width the stream needs when it is at a maximum flow and creates a pinch-point in the stream. Think of a water hose: When you pinch it you can create more pressure as the water comes out. In those situations, as water is forced through the smaller opening, water flows increase in speed and energy, and the water exiting the crossing can erode, or scour, the streambed, banks, or both. This can often result in a small area immediately downstream of the crossing that is deeper than the stream is upstream of the bridge or culvert – this is called a scour pool. If the amount of scour comes close enough to the culvert, pipe or bridge foundations, it can erode the ground under the crossing and risk destabilizing the crossing, including the road on top of the crossing.

When faced with these situations, stabilizing the stream bed and banks while protecting the culvert/pipe and road from being affected are interconnected goals.

A-Jacks: New Technology to Address an Old Problem

NHDOT routinely surveys stream crossings to determine if they are stable or if work should be done to either prevent scour from occurring or resolve scouring that is currently happening and may impact the crossing structure. In Woodstock, the stream crossing of Interstate-93 over Eastman Brook that was installed in 1972 is composed of a twin cell (or 2-sided) concrete box culvert; each side is 18’ wide. Original installation included riprap (stone) at the inlet and outlet of the culvert to prevent scouring. This riprap has washed away at the downstream outlet, and despite repairs of adding riprap on several occasions, the stream continues to scour downstream. Over time, this scour will jeopardize the stability of I-93, which is not an acceptable situation. Eastman Brook carries water that flows out of the White Mountains that can seasonally flow fast enough to carry even the largest riprap boulders downstream, particularly in spring, due to snowmelt combined with heavy rainstorms. Is there a different solution?

Hoyle Tanner’s experienced bridge design engineers proposed the use of A-Jacks in this location. They consist of two concrete T-shaped pieces joined perpendicularly at the middle, forming six legs. A-Jacks are designed to interlock into a slightly flexible, highly permeable matrix that will remain in the streambed. The highlight of this design is the ability of the A-Jacks system to spread out the energy that comes from water flowing quickly out of the culvert, allowing for increased resistance to the erosive forces of flowing water. Because they lock together in place, they can flex yet effectively stay put where they are installed.

The patented, two component design allows economical transport and on-site assembly. Just as you would picture a pile of jacks when you dump them onto the floor to play the game, A-Jacks interconnect and are assembled by sliding one half into another to form a complete unit. Rows of A-Jacks are assembled to interlock in horizontal as well as vertical directions. A-Jacks can be installed either randomly or in a uniform pattern. NHDOT has previously installed A-Jacks in four locations across the state and was open to the idea of using this alternative for the Woodstock scour stabilization project.

A-Jacks were installed downstream of the stream crossing in Woodstock this summer for approximately 87 feet. As shown in the photos, the streambed was excavated to  a depth to allow for installing a double row of 48” A-Jacks that raised the streambed elevation to meet the bottom lip of the outlet of the culvert and tied into the natural grade of the stream downstream of the crossing; this will allow for improved aquatic organisms and fish passage through the crossing by preventing the situation shown in the before photo, which is called a perched outlet. Thus, the design will accommodate the highest stream flows and will keep water running through the culvert during the low flows of summer so the stream doesn’t disconnect, and wildlife and fish can pass freely. Can’t see them? Clean washed gravel and stone was placed on top of the A-Jacks to fill the small voids (or spaces) between the individual units, resulting in simulation of a natural streambed.

If you look closely at this photo, you can see the tips of some of the A-Jacks sticking out of the streambed. This was intended to produce the natural variation in depth that a natural cobble-gravel-bolder streambed would have. 

Hoyle Tanner’s Environmental Coordination team effectively coordinated between NHDOT, the bridge designers, the NH Department of Environmental Services (NHDES), the US Army Corps of Engineers (USACE) and the NH Fish and Game Department (NHF&G) to obtain agreement from each respective permitting agency that the A-Jacks, despite technically being viewed as “fill” in the streambed, were necessary in this location and would result in the best overall result that met the goals of the agencies involved.

By using innovative design techniques, our team was able to effectively stabilize an important piece of infrastructure, prevent future scouring of the stream and damage to the stream crossing, and re-create a natural streambed with improved functionality for fish and wildlife. Just a day’s work for our talented bridge designers and environmental coordinators. Let us know if you have a tricky scour issue that you would like us to take on!