Jun
05
2017

RDS: The Benefits of a Truss Style Frame System

Posted 106 days ago ago by Eureka! Expeditionary Systems     0 Comments

The RDS was developed to achieve the following goals:

  • Structural Efficiency
  • Durable Performance
  • Ease of Deployment
  • Compact Packaging

STRUCTURAL

Prior to the RDS, all other fast setup structures relied upon “scissor system” designs. The deployable system utilized by the RDS is based on structural/mechanical principles that deliver measurable improvement in these areas over existing deployable tent systems. The key design advantage of the RDS systems versus scissor systems are:

               1)  The Creation of a Structural Truss.

 The advantage of the structural truss is a static load strength to pass 10 pounds per square foot snow loads without additional braces that often increase set-up time and deployment weight.

               2)  Fewer Moving Parts/Locking Pin Locations.

The advantage of fewer moving parts/locking pin locations is less failure modes and greater

system reliability.

 

To further explain, when the RDS is deployed, it forms a structural truss. Each section has a four-sided structure of compressive members with two diagonal tension cables. Upon deployment, the cables are tensioned becoming the major load bearing element.

 

In the RDS design, the tubes are pinned at the ends only. The other quick erect tents do not use the structural trusses by are “scissor-systems”. Tubes in scissor-system designs have pins in each end and at the mid-span and become the major load bearing elements.  At these pin points, the sectional properties are reduced due to the hole for the pin. In addition, the hole at the mid-span is located at the point where the tube has the greatest bending stress during deployment and the greatest opportunity for damage.

 

Also, scissor-systems are less efficient at handling structural loads. In the best case, their effective structural section is one-half the distance between scissor-ends. It can also be difficult to reliably tension perimeter cables further compromising structural performance.

 

Unlike the scissor-systems, applied loads to the RDS are resolved to compression/tension forces in the members providing high structural performance with a minimum of material.  Sectional properties are constant along the span of the RDS, giving consistent structural performance. 

 

The RDS design also allows for high point loading at the nodes (hubs).  These hubs are structural members that efficiently transfer the point loads (from fabric or from hanging equipment to the truss system.

 

DURABILITY

The RDS is an efficient truss structure, and it is proportioned in a rational, optimized manner. Its part count is similar to standard non-deployable truss systems, and is lower than typical scissor-systems, which require extra members to distribute applied loads. Lower part count means that structural members may be sized significantly larger than scissor-systems without weight penalty. These larger structural sections are far less susceptible to damage than the smaller members in scissor-type structures.

 

EASE OF DEPLOYMENT

Scissor-systems (like most other frame design systems) require tie-downs for stability. The RDS structural system (with the exception of the RDS-150) does not require tie-downs (wind guys) - staking the support legs is sufficient. In addition, the RDS does not require any additional cables or supports or special attention to meet snow, wind or wind/rain loading.

 

The RDS has been designed to streamline and simplify the deployment process. One key factor to achieve this has been to minimize lifting forces and eliminate all overhead lifting during deployment. Because there is little lifting (and no overhead lifting), service-personnel remain in a comfortable standing position throughout most of the deployment.

 

Scissor-systems require a significant overhead upward lift mid-way through deployment. In the scissor-system, the stop from A to B requires significant vertical center of gravity movement and overhead lift. (See above)  This is because scissor structures are spread outwards first, and only then take on the curvature. This latter part of deployment is when the major lifting occurs.

 

As a secondary deployment feature, the RDS is deployed in two stages, it is lengthened along a first axis, and then spread along a second axis. This provides a clear, simple deployment sequence requiring minimal training. By contrast, scissor-systems combine both synchronous features and sequential features, which require more skill and training for deploying personnel which adds the potential for error and damage.  Because of the simple procedures and reduce overhead lift, the RDS can be quickly and easily deployed.

 

COMPACT, YET HEAVY DUTY

Based on its unique, patented system, the RDS utilizes gears to synchronize the movement of its members during deployment. The main benefit of a geared system is that it provides consistent synchronization throughout deployment.

In contrast, scissors provide poor synchronization during initial deployment stages, which could result in confusion during deployment and increases the likelihood of accidental breakage. When the RDS is stowed, the fabric roof material is pulled into protective regions created by the roof structure, thus reducing the possibility of damage to the fabric during transport.

 

Due to the advanced structural design of the RDS roof trusses, it is exceedingly strong and capable of supporting significant point loads. Many objects that use to take up valuable floor space may now be suspended from the extremely rigid and stable roof allowing for more flexible usage of the shelter.

 

For more information about the RDS from Eureka!, give us a call at 800-235-2607.






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