Not always but in some places where hurricanes and tornados and Floods are frequent it might be a good idea to anchor our shipping container home to the ground
Typically an empty 20-foot shipping container weighs between 1.8-2.2 metric tonnes (about 3,970 – 4,850 lb) and an empty 40-foot shipping container weighs 3.8 – 4.2 tonne (8,340 – 9,260 lb) depending on what kind of container it is. For example, high cube containers tend to be heavier.
Heavy for a person to push it, but like a feather for tornados or hurricanes, that can move them like toys even turn them upside down and a flood will make it float like a piece of cork and will take it as far as it can.
there is not just one way to do it, but here are some examples
We should learn how to tie them down from shipping companies who they do that every day for a living, and they became experts in the matter.
How do you anchor a shipping container to the ground?
Penetrators screw right into the ground. For cabled anchors, you’ll use a drive rod to drive the anchor into the soil. The anchor’s cable tail follows it down, and when at depth, the cable is pulled back to rotate and lock the anchor. Popular cable tie-off methods include thimble loop, cable clamps.
Container Securing Rules
Here are some sections and articles to secure shipping containers during its transportation that we can extrapolate and use to secure our home.
Title 49: Transportation Part 393: PARTS AND ACCESSORIES NECESSARY FOR SAFE OPERATION
I will intentionally take-out the part related to the movement of the container during its transportation, but you can read all the rules here.
(3) The front and rear of the container must be secured independently.
(1) All lower corners of the intermodal container must rest upon the vehicle, or the corners must be supported by a structure capable of bearing the weight of the container and that support structure must be independently secured to the motor vehicle.
(2) Each container must be secured to the vehicle by:
(i) Chains, wire ropes or integral devices which are fixed to all lower corners; or
(ii) Crossed chains which are fixed to all upper corners; and,
(3) The front and rear of the container must be secured independently.
Each chain, wire rope, or integral locking device must be attached to the container in a manner that prevents it from being unintentionally unfastened while the vehicle is in transit.
(4) The empty intermodal container is secured to prevent lateral, longitudinal, or vertical shifting.
[Federal Register: September 27, 2002 (Volume 67, Number 188)]
[Rules and Regulations]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
Shipping container parts & accessories
Shipping Container Twist-locks
Are the natural idea for securing a shipping container, but if you’re not regularly involved with containers you may not be aware of that they are. They are used to secure shipping containers in a stack, the primary uses are for locking a container into place on a container ship, semi-trailer truck or railway container train, and for the lifting of the containers by container cranes and side lifters. The same can be used to anchor our container to our foundation either concrete, metal or wood-beam.
In a residential used they could be built into a cement foundation and when the container is set in place all that needs to be done is twist the anchor and the container is locked down tight.
A twist-lock and corner casting together form a standardized rotating connector for securing shipping containers.
Shipping Container Corner Casting Rebar
Are located on each of the eight corners of the shipping container and have holes on each of the sides. Iron rebar that’s commonly used in concrete work can be wrapped through the holes in the corner castings and twisted to secure the container to the foundation, or simply driven deep into the ground.
The last option, and the one that probably requires the least amount of effort, is to simply chain the shipping container to the foundation. This can be done with a heavy-duty steel chain that is fished through the eyes of the corner casting. Some form of a hook or bent rebar will be required on the foundation to connect the chain through.
Corner Casting Rebar
“There is a whole GUIDE TO FOUNDATION AND SUPPORT SYSTEMS FOR MANUFACTURED HOMES, published by PATH (Partnership for Advancing Technology in Housing) that is a private/public effort to develop, demonstrate, and gain widespread market acceptance for the next generation of American housing. PATH is managed and supported by the U.S. Department of Housing and Urban Development (HUD). In addition, all Federal Agencies that engage in housing research and technology development are PATH partners including the Departments of Energy and Commerce, as well as the Environmental Protection Agency (EPA) and the Federal Emergency Management Agency (FEMA). State and local governments and other participants from the public sector are also partners in PATH. Product manufacturers, home builders, insurance companies, and lenders represent the private industry in the PATH partnership.
Both the NFIP regulations (44 CFR 60.3) and the HUD Model Manufactured Home Installation Standards (24 CFR 3285.305) require that manufactured homes installed in flood-prone or SFHAs be anchored to resist flotation, collapse, or lateral movement”.
Types of Anchors and Installed Configurations
HUD considers Shipping container Homes as Modular and not manufactured, but that is another issue that has to do with ist mobility and code regulations, but for the types of anchors to use in our house, we can use their guide without any problem. both will behave in similar ways.
“Several styles of anchor assemblies are available that can adequately secure a manufactured home to resist flood, wind, and seismic forces. Helical earth anchors, cast-in-place concrete footings, drilled concrete anchors, and cross drive anchors are just a few of the types available.
“Helical Earth Anchors
Helical earth anchors are designed to be augured (screwed) into the ground and are often referred to as ground anchors. Helical earth anchors typically consist of a shaft, head, and one or more helixes. The head is used for installing and fastening the anchor to the home, and tensioning the anchor. Toward the bottom of the shaft, there is one (single) or more helical disks for the anchor to be screwed into the soil. The helix provides much of the anchor’s load capacity. The typical lengths of helical ground anchors are 30, 36, 48, and 60 inches.
Helical anchors also may be installed with stabilizer plates to increase the lateral capacity of the anchor by enlarging the surface area used to develop passive soil resistance”.
“Steel ground anchors are the most common anchor assembly application for manufactured home installations. Ground anchors are typically constructed with a circular shaft of one or more helixes; ahead connects at the opposite end of the anchor, which then connects to the home’s frame and/or sidewalls with steel straps or cables. Anchor shafts are typically 5/8 inch to 3/4 inch in diameter, and helixes range from 3 inches to 8 inches in diameter. Most anchors used for manufactured home applications have one helix, although anchors with two to four helixes are available”
“The above figure shows Single and double helix ground anchors with strap connection and single helix anchor with a closed-eye connection”.
“Most anchor heads are “U” shaped and contain predrilled bolt holes. The bolts connect the anchor to the home’s frame or sidewalls with 1⁄4-inch anchor straps. Some anchors have heads with closed eyes for cable connections. The bolts in “U” shaped anchor heads can be used to pre-tension the anchor. Pre-tensioning an anchor with closed-eye heads requires using other devices like turnbuckles.
HUD requires anchoring equipment and anchoring assemblies to be capable of resisting allowable minimum working loads of 3,50 pounds and ultimate loads of 4,725 pounds without failure of either the anchoring equipment or the attachment point on the manufactured home.
Ground anchors are used with masonry piers, wood posts, or steel jack stands. For satisfactory performance, the piers, posts, and stands must function with relatively large displacements that the anchors may experience when subjected to flood, high-wind, or seismic loads. Large displacements are especially likely for non-axially loaded ground anchors. If subjected to relatively large movements, many foundation components cannot maintain their integrity. Piers, for ex- ample, can experience failure due to sliding of unmortared blocks or overturning of reinforced piers supported on ground surface pads.
Ground anchors should be selected based on the specific soil` conditions at the manufactured home site. Short anchors with smaller helixes may be used in firm, well-compacted soils. Longer anchors or anchors with larger or multiple helixes are required in weaker soils.
Most anchors are selected based on standard torque probe tests conducted at the site. During those tests, a 5-foot long auger probe is screwed into the ground to the approximate depth of the anchor helix. A torque wrench measures the torque required to advance the probe. The resulting torque value is used to classify the soils and select appropriate anchor-based recommendations of the anchor manufacturers.
When fastened as vertical wall ties and loaded axially, ground anchors may be used without stabilizer plates. When ground anchors are used with some proprietary foundation systems, anchors can be installed 45 degrees to the horizontal and loaded axially.
The capacity of anchoring systems is a function of the soil response to loads applied to the anchor assembly. For ground anchors, important geotechnical considerations include soil type or classification, soil shear strength, load-deformation characteristics (i.e., modulus of subgrade reaction, or stiffness), and moisture condition. Research has identified additional considerations impacting the capacity and performance of ground anchors, including anchor geometry, anchor depth, anchor orientation, and direction of the load relative to that orientation.
Soil response mechanisms are different for axially and non-axially loaded ground anchors. Soil response for axially loaded ground anchors is the result of shear stresses along the failure plane.
Failure occurs when the stresses exceed the soil shear strength. The geometry of the failure surface varies based on the critical depth of the anchor. Ground anchors with an embedment depth less than the critical depth to anchor base width ratio ((D/B)cr) respond as a shallow foundation. Ground anchors with a depth greater than (D/B)cr respond as a deep foundation. Anchor failure may also result from weld failure between the anchor shaft and the anchor head, weld failure between the shaft and the helix, collapsing of the anchor helix, or metal tearing around the anchor head strap bolts”.
Concrete anchors use the dead weight of a concrete footing or a combination of concrete weight and soil uplift resistance. Uplift resistance can be increased by the use of drilled concrete piers. In both cases, the home must be securely attached to the concrete elements using anchor bolts, tie-rods, or other structural connections. Anchor attachments placed in concrete must be installed with an adequate depth to develop the required strength. The load capacity of the anchors must be sufficient to resist applicable design loads”.
“The three graphics showing the anchor configurations From left to right, they are (a) ground anchor installed at 45 degrees and loaded axially, (b) ground anchor installed at 15 degrees from vertical and loaded 45 degrees from horizontal, and (c) ground anchor installed vertically and loaded axially”.
“Cross Drive Anchors
Like helical ground anchors, cross drive anchors are constructed with a head secured to a metal shaft. Cross drive anchors are shafts driven into competent soils to develop their resistance. As their name implies, cross drive anchors are driven in pairs that form an “X” or cross. The heads of the anchors are secured to the home with metal straps”.
For those living in Florida or areas prone to Hurricane wind forces
Here you have a link to Florida Building Code regarding anchoring. “Anchor embedment into masonry shall be into the face shell, not mortar joints. … All Geosynthetic Hurricane Screen assembly details depicted within these ..”
For those Living in areas prone to Flooding
Even though the shipping container is a waterproof unit, building a floating platform will give extra floatation capabilities and a solution could be installing four poles, one in each corner and secure them with a ring in such a way that it allows only vertical movement to raise and lower with the tide but not sideways.