Michael’s Mountain Lakes Bridge

Project Description

The purpose of my project is to enhance the pedestrian traffic in Mountain Lakes Preserve (which includes a lake, and roughly 9 miles of trail). Mountain Lakes is located near Coventry Farm, Community Park North, and the John Witherspoon Woods. It is located off of Mountain Avenue, which originates at Route 206 in Princeton Township, New Jersey. 

My project is situated on a one-third of a mile trail. This trail is located perpendicular to Coventry Farm and is on the west side of the lake in the Mountain Lakes Preserve. When it rains, a ditch on the trail slightly swells with water and the sides get slippery. During dry periods, the loose rocks on the sides of the trail represent a slipping hazard. To make the trail safer and more accessible to the preserve, I plan to build a 16-foot long by 4 foot wide by 3 and a half-foot tall bridge that spans the 8-foot deep by 10-foot wide ditch (probably used as a drainage ditch by Coventry Farm). Secondly, I will extend the pre-existing trail, so that it leads to the openings of the bridge instead of into the ditch. This extension will cover be a total of 40 feet long (20 feet on each side) and have a width of four feet. To construction the bridge and extend the trail, I first need to remove the invasive honeysuckle. This removal will be done with clippers and Round-Up ©, but no workers under 18 will using the chemicals. This treatment for the honeysuckle has been used on other parts of the Preserve.

Location of Eagle Project

Present Conditions of Trail

Bridge Design

Proposed Location of Bridge
Day Workers Needed Time (Hours) Total Hours
1-4 4 scouts, 4 adults with a certain level of woodworking skill each day 4 hours each day 128
5 5 scouts, 2 adults 4 hours 28
6 5 scout, 2 adults 4 hours 28
7 5 scout, 2 adults 4 hours 28
8-9 5 scout, 2 adults 4 hours each day 56
Total Hours 296 hours  

Plan for Day-by-Day Work

Date Time Description Items Needed
Day 1-4 11:00-3:00 Set-up 4 work stations: 1) Layout and marking of girders, 2) Cutting, 3) Drilling, 4) Putting in bolts  
    Layout and Marking Station: Translating the drawing and marking the lumber where we need to cut and drill. We will also tag the lumber with a number so that we can later assemble it at site. Carpenter’s pencils, steel square, triangles, measuring tapes, copies of drawings, calculators
    Cutting Station: Using the marks from station #1, cut the lumber into sizes necessary for assembly at the site Portable circular saw with telescopic arm, measuring tapes, carpenter’s pencils, clamps, wood jig material (optional)
    Drilling Station: Using the marks from station #1, drill the lumber for the holes necessary for the bolts in station #4 Portable 16V drills, drill press, 1/2″ dia. drill bits
    Hardware Station: Using the holes created in station #3, put bolts, nuts, and washers in prefabricated components so that they are in the located necessary during on-site assembly 1/2″ and 5/16″ dia. lag bolts (various sizes), washers, lag bolt nuts
Day 5 11:00-3:00 Chopping down invasive honeysuckle. Removal of roots and rocks on the rail and the embankments for the bridge abutments.  Adult would squirt Round-Up on the roots of the honeysuckle at the end of the day when no more work will occur Round-Up, sapling cutters, shovels, pick-axe, and rakes
Day 6 11:00-3:00 Building abutments by cutting timber on location and placing the cut timbers into the embankments. Put gravel and woodchips on top of abutments. Chainsaw to cut timbers, shovels, wheelbarrows, timber spikes, sledge hammers, earth tampers, and pick-axes
Day 7 11:00-3:00 Bring prefabricated bridge girders, bridging, and decking material. Build bridge primary structure and platform. Cordless drill, cordless circular saw, socket and crescent wrenches, deck screws, string line, wheelbarrows, bags of gravel, and levels. 
Day 8-9 11:00-3:00 Bring prefabricated railings and attach to bridge deck and structure. Cordless drill, socket and crescent wrenches, and cordless circular saw

List of Planned Work Days

Please see attached schedule for the planned work days and times for this Eagle Project. Feel free to contact me if you have an scheduling concerns. I will also send out reminder emails before each session.

Progress of Project


First, we took inventory of all the materials received from Princeton Township, noting any irregularities. Then we began the prefabrication of the deck for the bridge. The scouts marked the 2x6x10 boards so that they would produce two 2x6s at 7′- 11 1/2″ deck pieces. After having my dad cut the wood, the scouts used a template and a tape measure to mark the half-way point of the board and the locations for the deck screws. So as to allow for the screws to enter the wood more easily during assembly, the scouts used power drills with a 7/64″ diameter drill bit to make holes in the deck pieces. While some scouts were doing this, another scout was marking the eight-foot place on each of the 2x10x8s so that they can be shaved down to eliminate excess and allow for a smoother connection during assembly of the bridge. Lastly, scouts marked the half-way point of each of the 4x4x10 posts so that they can be halved and used for tomorrow’s girder assembly.

Aaron marking the eight-foot place on the 2x10x8s

Afnaan drilling into the decking for the deck screws
Today was the construction of the girders that will support the bridge when it is finally completed. However, we first finished drilling the holes into three deck pieces that we marked at the end of yesterday. We also marked the location for the cut on the 4x4x8s so that they can be used as the four foot vertical suppor of the handrailing. Then we did the prefabrication of the girders by using the 2x10x8s that my dad cut down to exactly eight foot yesterday and marking the four foot place on them. Using a template placed on the four foot mark, the scouts then marked the place for the lag bolts to be later placed in. After that, the scouts brought all the pieces near the power tools station so that my dad could use the markings and put the holes into the wood. From this step, I organized all the scouts so that it was almost a sytem in which two scouts carried the wood to my dad, one scout held up the wood so that my dad could properly put the holes into the wood, and then two scouts to carry the wood from the power tools station and set the girders up so that the bolts can be placed in. Upon completion of the drilling of all the lag bolt holes, we used 5/16″ lag bolts, two washers on the outside and one in the inside, and a nut to attach the three boards together.  
Akil holding up the wood as my dad cuts the remaining 2x6x10s for the decking
Sidhant putting holes into the remaining deck pieces
Suveer and Naveen carrying a previously drilled 2x10x8 for a girder

Sidhant, Yasin, and Aidan standing on the two completed girders

Today we started the construction of the railings. The main portion of our work today was centered on the fabrication of the vertical supports for the railing. These supports were created by cutting the six 4x4x10s in half with a 45 degree angle cut at the middle and a 2 1/2″ angle cut on the other end of the post. After producing twelve of these, two adults drilled the holes for the bolts that will attach the posts to the already completed girders. However, for the 1/2″ carriage bolts to go in, we had to first countersink them. After countersinking the bolts, one scout used a cordless drill to finish the hole for the bolt in the wood. The other task accomplished today was that while the vertical posts were being fabricated, another adult finished cutting the bolts on the girders of excess, making it easier for us to carry the pieces, and we marked each junction on the girders with the system A,A; B,B; C,C etc. so that when we dissemble them for transportation, the girders can be easily placed back together.

Cutting a 4x4x10 in half with a 45 degree angle cut


Mr. Freedman removing the excess on the 5/16″ lag bolts


George marking a junction on one of the girders


Mr. Richer and Mr. Confer using the drill press to countersink the bolts

George completing the holes for the carriage bolts in a vertical support

We continued the construction of the railing by attaching the vertical posts to the already fabricated girders. We accomplished this by first marking location for each post on the girder using the drawing of the bridge as a guide. Aftering marking the location, we then marked the point for the holes to be drilled into the girder so that the posts could be attached. While doing these two tasks, I did incur some problems as the scouts were not very precious with their lines and location of the holes. This caused additional problems, for I did not realize their mistake until almost all the holes were driled. To fix this semi-major problem, I had my dad re-drill the holes in the proper location. While he did this, the scouts hammered the carriage bolts into the holes made the day before so that they would fit flushly into the holes, because on each carriage bolt there is a square undernearth the head that prevented them from fitting flat. We then attached the posts to the girders with 1/2″ diameter carriage bolts and a washer and nut on the inside of the bridge. For the last assignment of the day, the scouts and my dad worked to fit the decking on the bridge because there are pieces that must fit around the posts.
Carter and Jonathan working to attach a post to the girder
Mr. Treves cutting a deck piece so it can fit around railing post
Today we continued with the construction of the hand railing. As I waited for more scouts to come, I worked with one scout to mark out new deck pieces on five 2x6x10s because I needed to replace some that were miss cut the past Sunday. When more scouts began to show up and another adult came with more power tools, we started working on the four diagonal posts that would be attached to the end of the railing. We accomplished this task by angle cutting the top and bottom of the posts, countersinking for the carriage bolts, and drilling the guidance holes. After we did all this for all four posts, we put in the 1/2″ diameter carriage bolts, cut off the excess, and placed a washer and nut at the end of each bolt before tighening it.
Nathan marking wood for deck pieces
Working on attaching diagonal to railing structure
Mr. Treves removing excess metal on a carriage bolt
Today we continued with the construction of the hand railing. Since many scouts were newly adjusting to the summer hours of 9 am to 1 pm, my progress today was very limited. We first attached the side piece of the upper hand rail by pressing a 2x4x16 against the top and marking the angles so that it could fit with the rest of the railing construction. Using a table saw, we cut the entire piece of wood so that the angle cut on the vertical supports matched the angle on the side piece. After cutting and attaching the side piece with deck screws, we sanded the edge so that the entire construction of the upper hand rail would fit together smoothly. The other achievement of today was attaching the lower hand rail, in which we did the same thing except we did not angle cut the top of the 2x4x16. Lastly, we attached vertical 2x4s between the upper and lower hand railing at the mid-point between each large vertical post.
Anthony attaching the lower hand rail to the vertical supports
Anthony sanding the side piece of the upper hand rail construction
Today we completed the construction of the hand rail and made great progress with constructing the support system that will hold the two girders together. First, we completed the hand rail by marking a 2x6x14 so as it can fit with the rest of the hand rail, cutting the pieces of wood, and then angle cutting the edges. After that, I had all the scouts go around with a power sander and sand the edges of the upper piece of the upper hand rail so to make the diagonal end posts of the railing flush with the upper piece. I also had the scouts use sand paper and a block of wood to soften all the hand edges on the pieces of wood used to build the two hand rails. In the last part of railing construction, we cut and attached 2x4s so that they could fit diagonally between the large vertical posts and the vertical 2x4s we had attached the day before. The other project of the day was starting construction of the support that will go between the center 16 foot piece and the two girders. We decided that we will accomplish this through joist hangers even though the drawing originally called for diagonal pieces of wood connecting the girder to the center. So, I had scouts attach joist hangers to the two girders and translate the distance placed on the girders onto the center board. We ended the day with a small dilemma as the deck screws we used to attach the joist hangers on the center board were too long and went through to the other side.

Sanding the sharp edges on the bridge

Attaching a diagonal 2×4 to the main construction of the hand railing

Today was an easy day as we rapidly approach the end of pre-fabrication. The only assignments left to do is build the cribbling and re-attach the joist hangers to the central board, so we chose to tackle the cribbing and we finished it today. This was accomplished by cutting 6x6s and making a lip on each cut piece so that they can be staked together. After that, we used a drill to put a guide hole and then a sledge hammer to slam a stake so as to attach the different cut pieces.
Hammering a stake into one of the cribbings
A completed cribbing
First day of working in the field! Today involved some real hard and heavy working so I only reached out to the older scouts but unfortunately none said they could come, so my dad, brother, and I did the work ourselves. We spent about 6 hours in the field digging through roots, rocks, and soil so as to place in the cribbing that will support the bridge. Additionally, the holes had to be at least a foot deep to fit the cribbing. After we dug and fit the cribbing into the ground, we removed them and placed a layer of drainage stone below it and, after placing the cribbing back, also around it. Lastly, my brother collected medium size stones that we placed at the foot of the cribbing so as to hide the drainage stones and look more natural.
Only halfway there
Loosening the bank with a pick-axe
Shoveling out the debris

Complete installation of one cribbing

Complete installation of the two cribbings on the left and right of the photo
On the first of August, my dad and I collected large stones to place around and ontop of the previously installed cribbings. After hauling over a dozen enormous stones from the road up to the location of the bridge, we quit for the day. On August 2nd, we returned with my brother and we placed the stones in a manner that they fit together smoothly and snuggly. After placing the large stones and building up the sides of the cribbings with smaller stones, we poured and dispersed pea gravel throughout the construction so as to hold everything together and fill in all the holes. Lastly, before leaving, we spread a wild flower/grass seed mixture on the banks of the ditch and placed a large dead branch across one of the sides so as to hold back the loose soil from eroding in future rain storms.

Grass placed on the sides of the ditch

Current appearance of trail with the two installed cribbings and stone steps
Finally complete! Today we assembled the bridge in place. In the morning, we placed the two large side pieces on the set cribbing with one end sitting on the cribbing and one end sitting above it. We accomplished this by using a team of 4 adults and 6 scouts to lift the bridge sides, one at a time, so that it rested above the cribbing on one side and then we pulled/pushed the siding across the ditch so that it rested on both sides as we wanted it. We did this because there would not have been enough room to put the end pieces on the bridge had we placed both ends of the side pieces on the cribbing. After nailing the end pieces on both sides, we slide the whole bridge structure so that both ends sat on top of the cribbing. Next, we put in and nailed into place the internal support system, with the middle beam and the horizontal supports connecting the middle beam to the two sides. With only the finishing touches to do, we put the deck on. The spacing of the deck was done by my dad, because he had the best eye for it, while the scouts looked for large stones to add to the stone work. After collecting four large rocks, we screwed the deck on and I put a plaque that said that this bridge was an Eagle Project. Later in the afternoon, I came back to the site with my dad to make the final touches to the bridge. We found some more large stones and spent some time trying to get the stone work to fit perfectly together, so that it would not be a hazard to pedestrians on the trail. We also placed some dead fall on either side of the trail to guide people to use the bridge.
Lifting one of the heavy side pieces of the bridge
Placing one of the side pieces on one side of the ditch
Pulling the side piece into place
Putting the internal support system into place
Screwing the deck into place

The four who finished the job
Final Pictures of Bridge

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