April 6, 2018 by Robin Austin, PE, LEED AP, Civil Division Manager
Construction is underway to improve the safety and operations of the existing Alpha, Bravo, and Charlie Known-Distance Ranges used for Rifle Marksmanship Training at the Marine Corps Installations East – Marine Corps Base, Camp Lejeune NC. Improvements consists of demolition of existing range infrastructure and facilities and the reconstruction of the target safety walls, retaining walls and range support facilities. Additionally, side safety walls are being added between ranges along the existing berms.
Construction began December 18, 2017.
Construction duration is 606 calendar days.
Working closely with Whiting Turner and the Base CM, CATLIN is performing the civil engineering for the project. The design team includes Bamforth, MMSA, CBHF, LS3P, Jensen Hughes, and Osmundson & Associates. The project is expected to be completed in August 2019.
- Construction phasing is key
Construction phasing is critical if you have multiple ranges and at least one range needs to remain open during construction, and the construction period is 18 months. As part of the design, we required the contractor to submit a schedule showing the detailed phasing of construction. But for constructability analysis of the design, CATLIN had to come up with our own phasing and include in the design to show what work could be done when each range is cold/hot. We worked closely with range safety personnel to determine what resources were available such as placing a marine to restrict access to certain parts of the ranges. Phasing was based on the current SDZ data and a possible course of action (COA) received from the base.
- Sometimes the best approach for permitting is not the easiest approach
For this project area, there was an existing State stormwater low-density permit but it only encompassed a portion of the range. And at the time the previous permit was approved, none of the adjacent streams were classified as SA waters, but now there was an adjacent SA water. To make things even trickier, the site is split; with one portion within a half mile and draining to SA waters, and the other portion draining to SC waters. So when it came time to pull together the permit package for State stormwater approval by NCDEQ, CATLIN requested the State modify the existing permit to expand the project area to cover the entire range, and then review it based on two separate receiving streams (one SA and one SC) in addition to review of the addition of built-upon area for the proposed improvements to the range. We also maxed out future BUA for both drainage areas, to allow the Base an easier permit modification process on future projects at the ranges. The permit process required some back and forth with DEQ reviewers, but it was the best approach for the project and the Base. CATLIN submitted the project for express review on 3/6/17 and received State approval on 3/15/17.
- Erosion & sedimentation control design phasing must consider the construction phasing of the project.
So you finally figure out how best to construct three range improvement projects at one time, while keeping one range open at all times. But did you remember to phase the erosion & sedimentation control installation and removal according to your construction phasing? At the project site, there was a fairly significant stormwater ditch located between the pit buildings and the road running behind all three ranges. As part of the improvements, the ditch was being backfilled to construct the new road and the road was being demolished to construct the new ditch. In other words, we were flip-flopping the ditch and the road behind all three ranges, but we had to keep at least one range open. Having a very detailed construction sequence is critical. It was helpful to layout the sequence on the phasing plan, identifying what had to happen chronologically to move forward without creating a safety hazard for the construction team. Total disturbance approved was 26 acres.
- Canteen Fill Up Stations are sometimes more complex than you think
On outdoor ranges in the south, it gets hot. And marines need to fill up their canteens. During design, we discussed several options: the fancy automated fill-up stations like they have at airports, designated faucets with grates, or just a spigot. Initially, we were going to provide the fancy kind inside the pit and head building somewhere near the bathrooms. But the client had concerns that splashed water would make the floor slippery and that marines would tear up the automated fillers. So the design team changed the stations to 3 standard faucets per station, and added floor grates with catch basins that drain to the building sanitary. Catch basin and drain pipe sizing calculations were required to make sure the basins would not overflow in the buildings if a marine left the faucets running.
- Expeditious review of shop drawings and RFIs whenever possible.
This project has an extremely aggressive schedule with rigid phasing in order to keep one or more of the ranges open during construction. One of the ways we help keep the project on schedule is a very quick turnaround on shop drawing and RFIs whenever possible. Although not required by our contract, as the acting prime on project design, we’ve asked our subconsultants to help us out by reviewing shop drawings and responding to RFIs as quickly as possible. On nearly all submittals, we’ve been able to achieve a 2-day turnaround, if not same day.
- Clear and open communication with the contractor and CM.
The CM oversees many projects on base. Maintaining clear and open communication directly with the contractor has helped clarify issues that arise in the field for which a phone conversation can easily resolve. CATLIN continues to be available and present for the contractor and CM on this project.
Do you need an engineering partner on a training facility project? Contact us today at 910-452-5861 and let’s get started!