Engineering A Container Campus
15 min read or watch the related Urban Design Forum This project was part of a Partnership with Vanderbilt Engineering and Barge Design Solutions. Student Civil Engineering Team: Julia Finfrock, Terri Green, Chloe Namias, Sarah Politiski; Student Mechanical Engineering Team: Jeff Cui, Nick Goldreyer
Year after year the Civic Design Center has partnered with Vanderbilt University seniors to offer mentorship on their annual Engineering Senior Design Project. This year was no exception, and the partnership resulted in the ideation, preliminary design, and proposal of a Container Campus, a housing development composed namely of re-used shipping containers in Wedgewood-Houston, Nashville.
The hope was to create a sustainable mixed-use development as an oasis for Vanderbilt Graduate students outside of the bubble of the midtown undergraduate campus. The development proposal includes residential units, retail shops, restaurants and cafes, office space for the university, and large green spaces. The site could serve as an interim solution for the university to popularize the site before more permanent development occurs, and the containers could be reused again elsewhere. Additionally, the development would be quantitatively proven sustainable, using metrics from the Living Community Challenge (LCC).
The Location: Wedgewood-Houston
Unbeknownst to most undergraduate students, Vanderbilt owns a 12-acre tract of land in Wedgewood-Houston. In its early days, Wedgewood-Houston was home to post-revolutionary settlements, but it slowly transformed into an underused area with fledgling industrial installments. Today, the Vanderbilt property serves as a home for the university printing services, a large parking lot, and a storage yard, but the surrounding areas are slowly becoming a flourishing arts and cultural center of Nashville. Thus, the student proposal to transform Vanderbilt’s property into a usable space could not come at a better time.
The Containers: Defining the Look
A defining factor of this project was the decision to use 40-foot by 8-foot shipping containers. Each year, the United States imports significantly more units than it exports, leading to a surplus of shipping containers in the country. This development proposes a way to repurpose unused containers. Moreover, containers are designed to be stackable. During transit, they can be stacked up to eight containers high. This detail is a major asset that will foster the implementation of prefabrication and modular construction. Living in a small space also reduces one’s carbon footprint, contributing to the sustainability goals of the site. Lastly, the containers have a distinctive, industrial aesthetic that adds character to the mixed-use project.
Interior perspective of container residence bed room
Interior perspective of container residence living space
The Site: Imagining the Development
Inspired by the University Connections blog, this site plan emphasizes walkability and open space. 8 restaurants and 16 small retail units line Chestnut Street and the inner square of the property, which draw people into the site from the street. 89 residential units line the internal edge of the property and Fort Negley Blvd. for a quieter experience. The 1, 2, and 3 bedroom graduate student housing units can also utilize the common spaces on the corners of the open lawns. To minimize exposure to noise pollution, general office and research space line the east side of the property which borders an active rail line. A multi-use trail could be developed on the east side as well to protect mature trees and act as a sound barrier. Similar to Vanderbilt’s main campus, the site has large open lawns which could be designed to encourage public use and engagement with the area. A community garden and compost area support the site’s sustainability efforts, while also acting as a demonstration of onsite viability. Overall, the site provides 60% of square footage for residential, 20% for retail/dining, and 20% for office.
Site plan of a focus area
These Streetmix diagrams imagine what the main north/south boulevard and smaller east/west cross street could look like. To keep both the pedestrian and biker safe, landscaping divides the sidewalks and lanes. The bike lanes also tie into existing lanes on Fort Negley Blvd. and into already proposed lanes on Chestnut Street. With overall widths of 100 feet and 80 feet, the streets provide safe, comfortable access within the site.
The Details: Engineering the Containers
ASCE 7: Minimum Design Loads for Buildings and Other Structures was heavily utilized to begin designing the container buildings. Using these requirements and Load & Resistance Factor Design (LRFD), the applied loads were calculated, including wind, seismic, snow, and the minimum design live loads for the given type of structure (e.g. residential, retail, dining). The dead load of the containers themselves was also determined. Once these loads were calculated, the team was able to select a foundation type and begin designing. Since shipping containers distribute weight to their corner posts, square pier footings were utilized. These reinforced concrete footings sit two feet below grade to account for freezing and thawing, while still elevating the buildings a foot above ground.
Another important task was deciding how to connect the shipping containers, not only to each other but also to the foundation. After researching existing container buildings, the choice was made to use welding techniques. Shipping containers are already designed to vertically interlock at the corner posts, but welding these corners and the edges provides more structural stability. Moreover, to connect the containers to the foundation, steel weld plates will be placed into the wet concrete piers. Once the concrete has cured, the corner posts will be welded to the steel plates.
As aforementioned, shipping containers are stackable. However, making cutouts for doors and windows can compromise structural integrity. To account for this, all cutouts will be reinforced with steel bar framing. By using steel, the reinforcement can be welded to the container. When removing an entire floor-to-ceiling panel to connect containers, increased support is required. In this case, 4x4 steel beams will be inserted to provide vertical reinforcement.
To calculate energy demand, the residential units were modeled using a Department of Energy Software called BEopt. This modeling software factors in site weather, a variety of building construction parameters, and resident behavior to calculate the total expected energy demands. To meet the goals of the Living Community Challenge’s Energy Petal, an all electric site powered by solar panels was assumed. Simulations were conducted for the three residential unit configurations (studio, two-bedroom, and three-bedroom) using different building parameters. For example, varying the types and amounts of insulation or changing roofing materials focused on minimizing energy demand without excessively increasing cost. In particular, Variable Refrigerant Flow (VRF), a novel but mature technology, was found to be a substitute for typical central air heating and cooling, which significantly reduces electricity use. The following chart shows a comparison of the energy used by our studio apartment design compared to a typical home of the same size. Overall there is a 60% drop in annual electricity usage and the other apartment configurations show similar results.
The Water Petal of the LCC was also considered. To reduce water use throughout the development, non-potable water can be reused in landscape irrigation and common household uses that do not require high-quality water. About 40% of the non-potable demand can be met by graywater and stormwater supply if properly conserved and treated.
The Construction: Building it out
In constructing the containers and developing the site, prefabrication and modularization techniques were suggested. Prefabrication involves the manufacturing of the containers offsite so that they can simply be placed. Doors and windows would be placed and insulation could be sprayed among other elements that are the same throughout each container. Benefits of prefabrication include cost reductions, shortened schedules, increased worker safety and wellbeing, and higher finished quality. In a similar vein, modularization is the concept that since each container is a single, individual entity, they can be easily assembled on-site, clicking together like Legos.
Overall, a 77-week schedule with five steps is suggested, starting with the acquisition of the 643 containers in three rounds. Transportation to the offsite prefabrication center followed by the prefabrication and transportation to the WeHo site would occur next. Finally, the containers would be placed on-site and tied into utilities. Since this is quite a large site and would take time to develop, three phases of construction are shown below. Residential units would be placed first to accommodate residents as soon as possible, followed by the retail and office space. This interim solution could provide the university with a way to gain interest in the relatively unknown site and expand student presence in the Nashville community.
Glossary
Living Community Challenge (LCC)
The Living Community Challenge is a framework for master planning, design, and construction. It is a tool to create a symbiotic relationship between people and all aspects of the built environment.
ASCE 7
Minimum Design Loads for Buildings and Other Structures: An industry standard for calculating loads on buildings and other structures to be later used in structural design calculations.
Load & Resistance Factor Design (LRFD)
A method for designing structures that accounts for statistical uncertainties and compares required strength to actual strength.
Variable Refrigerant Flow
An HVAC technology that uses refrigerant as a medium for adding and removing thermal energy and operates on a standard vapor-compression cycle. Instead of heating or cooling air and ducting it throughout a space, the heated or cooled refrigerant is directly pumped to a conditioned space. An important characteristic of VRF systems is the ability to offer simultaneous heating and cooling of different climate zones with a common refrigerant loop. This can be useful during the spring and fall of temperate climates, much like Nashville’s.
Potable vs. non-potable water
Potable water is highly treated and safe for human consumption, usually coming from municipal water treatment plants or deep wells. Non-potable water is not safe to drink or cook with but can be used for irrigation and household purposes like washing machines and toilets. It typically comes from collected rainwater and/or treated greywater from showers and sinks.
Prefabrication and Modular Construction
A process where a building is constructed offsite using controlled plant conditions before being transported and assembled at a final location. This type of construction can incorporate a range of different building types and floor plans and manufactured sections are quick and easy to assembly on site.
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