SBMA Design App is a custom design tool for multi-tendon anchors an app exclusively developed for SBMA Ltd.




In 2012, SBMA Ltd. joined forces with hetGE to develop an in-house productivity app with a clear goal statement:

« Given the project specific conditions & parameters,
derive the optimum SBMA design solution. »

hetGE delivered a complete range of geotechnical engineering focused programming, design and development for an iPad app encapsulating the design and analysis procedures for SBMA type anchors.


Single Bore Multiple Anchor System
an innovative ground anchoring technique

Open foundation pit with SBMA Type anchors (on left), and stressing of SBMAs (on right)

Open foundation pit with SBMA Type anchors (on left), and stressing of SBMAs (on right)


The SBMA system is a ground anchor solution in either permanent or temporary form with the ability to reduce the quantity of required anchors when compared to a more traditional solution. Here are some brief information regarding this innovative solution.

Due to the difference between the elastic behavior of the grouted soil around the anchor tendon and the elasticity of the tendon, as conventional anchors are stressed to high load levels, a phenomenon commonly known as progressive debonding occurs prior to any load being transferred to the distal end of the fixed length. This results in grossly non-uniform distribution of bond stress along the fixed length.

Progressive debonding in conventional anchors

Progressive debonding in conventional anchors

Progressive debonding generally results in a highly inefficient use of the existing ground strength. In circumstances where the ground strength far down the fixed length is being utilized, the ground strength above this has been exceeded and only some residual strength is available.

However, a system that can transfer the load simultaneously to a number of shorter lengths in the fixed anchor bore without the occurrence of Progressive Debonding, will mobilize the in-situ ground strength more efficiently and result in a considerable increase in anchor capacity.

Increased capacity with multiple anchors in single borehole

Increased capacity with multiple anchors in single borehole

This unique system, which was originally designed and developed by SBMA Ltd, has been used extensively on a world-wide basis for anchoring in soils and weak rock and can provide between double and triple the working load of normal ground anchors over lengths of 8 to 10 meters. The system has demonstrated that in the majority of medium strength soils ultimate loads in the range of 250 to 400 metric tons can repeatedly be achieved.


SBMA Design App for iPad
a full featured mobile design app


hetGE delivered a complete mobile app solution for execution of the design and analysis procedures for this special type anchors. We have worked closely with Dr.Devon Mothersille, Managing Director of SBMA Ltd. to perceive his vision for the app and we took it to the next level using our expertise in developing mobile engineering apps.


Resulting product has become an invaluable asset for SBMA Ltd. as a daily go-to software during initial design stages either in client meetings or during on-location investigations for running both robust and precise anchor capacity analysis, which in return is helping them to set out more clear design directions and construction recommendations early on.

Here are some of the key features of SBMA Design App:

  • hetGE's unique «Touch Soil» technology refitted for soil parameters required for anchor design,

  • In-App reference manual, and on-demand information and charts,

  • On-the-fly estimation of anchor bond stresses whilst user investigates different design scenarios by simple sliding gestures,

  • Full compliance with BS8081 Code of Practice for Ground Anchorages.