2015 ASEE Zone III Conference

Introduction

1. Design criteria

2. Educational adaptation

3. Conclusion

Educational Adaptation of Cargo Container Design Features

Christopher M. Moore, Semih G. Yildirim, Stuart W. BaurCargo container homes have become increasingly popular around the world in the last 30 years. Because cargo containers are modular in design, they can be used to create efficient, cheap homes. Repurposing cargo containers into homes is a sustainable construction practice due to the majority of the structure coming from recycled materials. Many design parameters of cargo container homes parallel those of standard home construction methodologies (cold formed steel framing/light wood framing) and from a structural standpoint, cargo containers are an effective building material. This paper aims to discuss the design parameters of cargo container home construction and an educational application of the concept. Problem-based learning (PBL) methodology was applied in order to create a discussion group. Building types were handed-out, scaled model and poster presentation were prepared by teams according to defined design parameters. Educational activity is evaluated by survey and critical points are determined to improve.The concept of containerization has developed at great lengths over the past 300 years leading upto the modern cargo container. An American by the name of Malcom McLean is credited withthe invention and patenting of the cargo shipping container. His success in owning the 5th largesttrucking company in the United Sates (McLean Trucking Co.) allowed him to branch out tomarine transportation. After purchasing the Pan-Atlantic Steamship Company in 1955, he beganexperimenting with different shipping methods. It was during his time as owner of the companythat his idea for the modern cargo container came to existence. While it was not necessarily anew idea, the concept of an intermodal shipping container that could be loaded and unloadedwith ease became very appealing to the U.S. military. Their influence helped to have the cargocontainer accepted as the standard for shipping lines all around the world. The cargo containerwas issued a patent in 1958 for an “Apparatus for shipping freight.”The cargo container is known by many names. When used for shipping, it is mainly referred toas a “shipping container,” but can also be called an “ISO container,” “Conex box,” or “cargocontainer.” When used as a construction material, however, it is referred to as an IntermodalSteel Building Unit (ISBU). Cargo containers are constructed from weathering steel. Weatheringsteel includes alloying elements that affect the materials corrosion process. Weathering steelforms an amorphous inner layer that protects the integrity of the steel. Figure 1 shows theplacement of the layer as well as its composition. The continuity of the layer also adds to theprotection of the steel (1).. Schematic illustration of the corrosion product layers identified on steels exposed to rural and marine atmospheres for the periods of up to five years (1).Furthermore, weathering steel is an ideal material for cargo containers due to their exposure tonatural elements. Cargo containers spend the majority of their life outdoors on cargo ships, trainsand trucks with little protection from moisture. The cargo container is an appealing constructionmaterial for a variety of reasons. First, their strength and durability provide both structuralsupport and a long life span. Their weathering steel construction provides not only corrosionprotection, but also strength. Also, with a movement toward sustainable construction practices,the recycling of unused cargo containers for construction material puts an unused product to use.Also, the cargo containers modular construction simplifies the design process. Much like bricksor CMU, cargo containers are designed to specific standards. Table 1 lists the dimensions of thestandard sized containers.. Standard cargo container dimensions (2).Cargo containers also feature corner assemblies that interlock the containers to one another, asseen in Figure 2. The locking mechanism provides stability when multiple containers are being used in the construction of a building. Cargo containers are designed to be supported from the four corners they sit on, which provides structural foundation advantages.Illustration of corner locking mechanism (3).Cargo containers are a useful construction due to their high availability. The cost of shippingempty cargo containers back to their starting location is higher than the cost of buying a newcargo container, so many containers are left sitting empty in ports all around the world. In 2012,according to Drewry Maritime Research, the global container fleet consisted of approximately32.9 million TEU (Twenty-foot equivalent unit) (4). That figure would estimate 32.9 millionstandard 20 foot containers, meaning that there is no shortage of cargo containers in the markettoday. Overall, the cargo container should be viewed as a valuable construction material.Cargo container homes require a foundation system just as any other residential dwelling would.While the design parameters for shipping container homes are constantly evolving due to therelatively young age of the technology, there seem to be two major methodologies in regards to afoundation system. Most cargo container homes utilize either a slab-on-grade foundation or aconcrete pile foundation. A basement is possible with either of those two types of foundations,but because the cargo containers are intermodal containers (and thus can be moved easily) abasement would not be practical. Moving the containers would leave a large void that would bewasted. While a basement is possible, the scope of this paper will cover foundation systems forcargo container homes that do not have a basement.As applied to cargo container construction, a home utilizing a slab-on-grade foundation systemwould lay a foundation and set the cargo containers on top of the foundation. This foundationsystem is a very simple methodology for cargo container homes. The modular units are placed onthe floor slab and secured with bolts or fixtures set in the concrete slab itself. The slab-on-gradefoundation system offers a solid platform that will easily support a cargo container home. Analternative to the slab-on-grade foundation is a deep foundation system. Two common types ofdeep foundations are a pile system and drilled pier system. The difference between the twosystems is evident in their construction. A pile is typically a precast concrete cylinder that isdriven into the ground, while a pier is cast on site in a drilled well. Due to having less dead loadof a low-rise housing unit compared to a commercial building such as; shopping mall, mid orhigh rise hotel/office building etc., precast pile have a better solution over drilled piers inconsideration of cargo container homes. This foundation system is also referred to as a raisedfoundation that is created by using precast piles. The home pictured in Figure 3 is clearlysupported only by precast piles.. Cargo container home using precast pile foundation (5).The cargo container’s steel construction provides the strength to stack containers upwards of 7high. That strength, however, is dependent on the entire steel frame/supporting walls intact.Many cargo container home designs require the removal of entire sidewalls of the container,which has an obvious effect on the strength and safety of the containers. Giriunas, Sezen andDupaix performed a container model analysis using SolidWorks, Hypermesh and Abaqus/CAEto collect information on the effects of removing steel sections from cargo containers. Theircomputer analysis compared 5 different loading scenarios on both unaltered and alteredcontainers. Their results validated the claim that containers with walls removed yielded beforethe required capacity specified in ISO standards. Also, they determined that the roof had littlestructural significance, and that the end walls were the strongest load resistive components whensubjected to vertical loads. Their research will hopefully lead to standards and specifications forthe use of cargo containers being used in non-standard applications, following full scale testing (6).. Deformation and prevention for cargo containers (7).While there is very little literature currently available that discusses the statistical data andrequirements for reinforcing cargo containers for residential use, there are many commonmethods that are used to both reinforce and secure the cargo containers in a safe and effectiveway. In regards to reinforcing, one concern is that the removal of major walls will cause sag.Figure 4 depicts both the potential deformation involved with the removal of walls, and apotential solution to the problem. Steel guardrails can be welded to the interior of the structure toprovide additional support and stability for the container. The amount of reinforcement needed dependson the amount of material removed, and as previously stated, there are currently no setguidelines or building codes in regards to this issue. Along with the structural reinforcement, theconnection of the modular units is a concern. Vertical connection is relatively simple, due to thenature of the container. Every container is designed with a fitting on each corner, originallyintended to secure the containers in organized stacks during shipment. Those same cornerconnections prove essential in multi-story cargo container homes and can be used to secure themodular units together. This methodology is applicable when the containers are oriented insimilar directions, as in Figure 5. Because the cargo containers are constructed from steel,welding can also be used to secure containers together in a permanent fashion. Securing thecontainers to the foundation is often successfully done by welding the containers to steel bracketscast in the foundation to provide a solid base for the home.. Cargo container home secured with original corner fittings (8).A cargo container home’s infill system is one of the most functional and aesthetically pleasingaspects of the building. The infill system consists of the MEP system (Mechanical, Electrical andPlumbing), as well as aesthetical components. The home’s insulation is also included in the infillsystem. In many ways, a cargo container home’s infill system is similar to that of a home buildfrom a traditional steel or timber framing system. Cargo container homes, however, have manymore spatial limitations, as compared to a normal home or building. The design challenges aremost prevalent in this portion of the design process because while the same families ofcomponents are necessary in a cargo container home, there is much less space to place them.It has become a very common practice to first construct a non-loadbearing frame around theinside of the cargo containers. Both cold-formed steel and light timber can be used, and theframing system parallels that of a standard home. This internal framing offers both a means tohang drywall or gypsum board as well as a cavity to locate insulation and components of theMEP systems. Figure 6a depicts the construction of an internal steel framing system to separaterooms of the cargo container home. Also, voids can be cut into the container and framed in toallow for standard windows and doors. After the framing is complete, the electrical andplumbing systems can be installed. Again, the wiring and routing of plumbing is very similar tothat of a standard home, with the exception of spatial requirements. Ventilation/central heatingand cooling is a major challenge due to the height restrictions of the containers. A standardventilation system is possible, however, with the usage of shallow ductwork concealed within aslightly suspended ceiling. Also, radiant heating and cooling systems require less space becauseof their use of hoses instead of metal ventilation ducts. The insulation methodology is again,similar to that of a home constructed by a standard methodology. Both insulating foam andblown insulation are possible insulation methods, and due to the internal framing, space isavailable to do either method. Many cargo container homes have become very successful increating a modern, appealing interior design. Figure 6b features the interior of a cargo containerhome. The application of drywall, hardwood flooring, standard appliances and furniture, andlighting creates a home that is very similar to a modern home constructed using a standardmethodology (i.e. without using cargo containers).. (a) Internal framing system for cargo container home (9), (b) Cargo container home interior (10).“Materials and Methods of Building Construction” (Curriculum code; ArchE2103) course inMissouri S&T Architectural Engineering Program covers a variety of educational methodologiessuch as; traditional lectures, assigned supplementary reading, documentary movies,demonstrations (material test, site visit, and brick masonry wall mock-up assembly), discussiongroup and hands-on learning experiences. Among these methodologies, a discussion/work groupwas created consisting of three or four students working together completing hands-on tasks. Thediscussion/lab section of the course was divided into four modules. One of these modulesfocused on the implementation of cargo containers as a structural unit for an office space design.The duration of this study was three weeks with eleven teams.Cargo containers are of particularly interest as a design platform because of their emergingpopularity worldwide. They are very versatile because of their durability and relatively low cost,thus make for an interesting subject in showcasing the possibility of modular design.Problem-based learning (PBL) methodology was applied in this section on cargo containerimplementation and in the latter module, which focused on residential home building utilizingconventional structural systems with variable floor layouts. Prior to introducing the “PBLblocks”, a series of “preparatory learning blocks” were offered. This allows the students tobecome more acquainted with the subject. Preparatory blocks should provide students withknowledge they can apply in PBL blocks, and the PBL blocks motivate students to explorefurther in-depth study (11). The “discussion group” study is also grouped in second module of thecourse and it can also be classified as preparatory learning block. In introducing this topic tostudents, a short presentation was given providing an overview of this design concept as well asdetails into the specification of the cargo containers’ design. Getting a little more specific, thisshort presentation included the information regarding materials of construction, standard dimensions,load capacity, limitations, reason of usage in construction industry and lastly somebuilt-up samples. This problem is being introduced to the class to be identified, formulated andsolved as a real life problem with architectural engineering practice. One of the challenges of thisassignment is determining the boundary or scope of work. This study, which is rather openended, allows for students to purse the idea further with their own research or imagination.Due to time limitation of three weeks, typical building layouts are handed-out to the students atthe beginning. Therefore, it was not a design studio activity, but an activity for each team to discussthe subject and make an assessment of requirements mentioned in the rubric. Results of the activitywere submitted as assignments. From the construction of the models, the groups learned the designfeatures, critical points, construction methods and building envelope of the cargo container. Designcriteria were defined as;a) An office or retail space with maximum 2 storiesb) Modular cargo container unit dimensions are;- Unit 1: (l x w x h) (20’ x 8’ x 8’ 6’’) (6.058 m x 2.438m x 2.591m)- Unit 2: (l x w x h) (40’ x 8’ x 8’ 6’’) (12.192 m x 2.438m x 2.591m)c) Building types (Figure 7). Building types.Each team submitted the results of discussion on;a. 20’’ x 30’’ foam board as “Poster Presentation” (including text and images). (70% of grading)b. Scaled model with cardboard (1/50 scale) (30% of grading).Expectation from the discussion groups and the content of the poster presentation is mentioned inrubric. In the future, the groups could present their work as an authority on the subject of cargocontainer design, which would help encourage group collaboration and further discussion. Scaledmodels were assessed as sufficient or insufficient. The minimum requirements for successfulcompletion of the cargo container design are a complete consideration of all of the designchallenges presented in their poster. The posters were graded as per handed-out rubric. Theseitems were to be addressed as if the group were to implement a particular solution to this problemand for addressing the challenges of completing an inhabitable and marketable office space.The grade of the group is reflected by the successful completion of two different tasks, the posterwhich has details of the solution for successful design completion and the scaled model of thebuilding/site made from prescribed materials, which in this case was foam board and corrugatedpaper. Samples of poster presentation and scaled models in 1/50 are shown in Figure 8 and 9.These models were graded on their accuracy, workmanship, and design vision and are a greatmethod for understanding the 3-dimensional space of each building layout.. Samples of poster presentation. Samples of scaled model in 1/50 scaleThe results of multiple educational methodologies have been evaluated by survey during thesemester (Table 2). The survey was completed by students two times as before and after the termproject. But, both were after the cargo container design activity and therefore the average of bothsurvey is being reflected on this paper. There were 36 participant at 1st survey and 25 participantsat 2nd survey. 73 percentage of participants’ academic standing was sophomore and 54percentage of participants had no construction experience. The rate of significance of thisdiscussion group as cargo container design activity was 6.12 out of 10 and this rate was thelowest rate among other similar activities. These activities are compared to find out the criticalpoints and improve the educational value of cargo container design activity. A partial masonrywall mock-up has been assembled by each team in a two weeks study. Drawings of the demowall and assembly instructions were handed-out the students prior the activity. It was a task thateach steps were clearly defined initially. Therefore, students’ feedback was fairly positive as 8.27out of 10. Similarly scaled model assembly as term project was a task project having clearlydefined hand-outs (design guide) prior the activity. Whereas, students have to think outside thebox in cargo container design activity. In Table 2 number 1 and 3 activities can be named as thetask projects, but number 2 – cargo container design activity - was a discipline project. This canbe the possible reason of having lowest rate of educational significance. In terms of analogy of afootball game, this means that playing field is specified, some overriding guidelines are given forthe game, but the ball has not been kicked off and thus the group must enter the field and set thegame into play. The freedom on design or studied subject is increased and limitation on PBL isdecreased in discipline project than the task project (12).. Average rate of significance of educational activities.In order to increase the rate of significance of this educational activity, critical points aredetermined and some improvements are proposed herein.a. Link between poster presentation and the scaled model; separated studies were run atboth assignment by teams but, more powerful link shall be maintained between twoassignments.b. Design flexibility on building types; design flexibility can result in handling moreresponsibility and sense of ownership over students instead of handing-out pre-definedbuilding types.c. Duration of the activity; the activity lasted 3 weeks as part of the lab and it was not aterm project. It is recommended to do this activity in longer time and/or as a term project.Cargo containers are a valuable modular construction material to be considered when designing ahome. They have the structural capability and design parameters to produce a standard, livinghome in a variety of ways. Cargo container homes are both sustainable and cost effective due tothe repurposing of the container itself. Container homes can be designed very similarly to astandard home, and should be heavily considered in today’s market. Design standards like thosepresented in this paper should be standardized in order to create an efficient design process toproduce cargo container homes on a larger magnitude. In order to increase the popularity of thisreusable modular construction units, future architectural engineers shall be promoted and theyhave to be competent over basic design features. By using existing design parameters of cargocontainers, a discussion group project has been created as a real life problem. The disciplineproject as part of problem-based learning lead the students to think outside the box which wasthe main goal of this educational adaptation. Student survey shows that positive feedbacksreceived from the students but improvement is necessary to increase the effectiveness of thisactivity.1 Revie, R. W., 2011. Uhlig's corrosion handbook. Third Edition, John Wiley & Sons, Inc., pp. 621-631.Tokyo.2 Intermodal Container. [Online]. Available: http://en.wikipedia.org/wiki/Intermodal_container . [Accessed28 April 2015].3 Campbell-Dollaghan, Kelsey, 2014. The Simplest Metal Mechanism That Changed the Global EconomyForever. [Online]. Available: http://gizmodo.com/the-simple-metal-mechanism-that-changed-the-globalecon-1530878459 [Accessed 5 June 2015].4 W. S. Council, "About the industry," 2015. [Online] Available: http://www.worldshipping.org/about-theindustry/containers/global-container-fleet [Accessed 1 April 2015].5 You can turn a $2000 shipping container into an epic off-grid home, 2014. [Online] Available:[Accessed 16 April 2015].6 Giriunas, K., Sezen, H., and Dupaix, R. B., 2012. Evaluation, modeling, and analysis of shipping containerbuilding structures. Engineering structures, vol. 43, pp. 48-57.7 How to build a shipping container home, 2002. [Online]. Available: http://www.residentialshippingcontainerprimer.com/action%20it . [Accessed 16 April 2015].8 Strether, L., 2015. Home, sweet shipping container, and why not? [Online]. Available: http://www.nakedcapitalism.com/2015/02/home-sweet-shipping-container-not.html . [Accessed 17 April 2015].9 Hart, K., 2001. Building with shipping containers. [Online]. Available: http://www.greenhomebuilding.com/articles/containers.htm . [Accessed 20 April 2015].10 Shipping container home interiors. [Online]. Available: http://decoratingbeautifulhomes.blogspot.com/2014/12/cargo-container-home-interiors-shipping.html . [Accessed 20 April 2015].11 H. K. Banerjee and E. D. Graaff, 1996. Problem-based learning in architecture: problems of integration of technical disciplines. Eurpoean journal of engineering education, vol. 21, no. 2, pp. 185-195.12 Graaff, E. D., Anette Kolmos, 2003. Characteristics of problem-based learning. Int. J. Engng Ed. Vol. 19, No. 5, pp. 657-662, printed in Great Britain, Tempus publications. [Online] Available http://www.ijee.ie/articles/Vol19-5/IJEE1450.pdf Christopher M. Moore, Undergraduate Student, Department of Civil, Architectural andEnvironmental Engineering, Missouri University of Science and Technology,email: cmmnpb@mst.edu Semih G. Yildirim, Ph.D., (Corresponding Author), Visiting Scholar, Department of Civil,Architectural and Environmental Engineering, Missouri University of Science and Technology,email: yildirims@mst.edu Stuart W. Baur, Ph.D., Associate Professor, Department of Civil, Architectural andEnvironmental Engineering, Missouri University of Science and Technology,email: baur@mst.edu Download article (pdf) 1.03 MB