Staggered anchor BBV-multibond®

With classical bonded anchors, the main load is already transferred on the "first" approx. 2-3 m of the grouted section. Due to the significantly lower residual shear strengths, an extension of the grouted sections L_tb > 6-7 m only leads to a slight increase in the anchor load-bearing capacity. In the case of staggered anchors, on the other hand, the anchor load is introduced into the grout body in a staggered manner via several load introduction sections and transferred into the ground.

The BBV-multibond® injection anchor introduces loads into a common injection body by staggering the bond lengths of the strands along their length. Due to the staggered internal force application, the external load transfer of the grout body into the foundation soil is also staggered.

As a result of intensive research and development work, BBV-Systems GmbH was granted the patent for the novel BBV-multibond® staggered anchor system. The innovative anchor system enables an increase of the known load-bearing capacities of classic grouted anchors by 100 % (2-fold) to 200 % (3-fold).

The resulting external skin friction is significantly reduced and the load is "evened out" over the planable activated removal length of the grout body.

Until now, the problem with staggered anchor systems was that the different free steel lengths (L_tf,long > L_tf,short ) generated unequal partial forces in the partial anchors when they were tensioned simultaneously.

The patented BBV-multibond® staggered anchor solves this problem by equalizing the partial stiffnesses of the individual partial anchors. By adjusting the cross-sectional area of each partial anchor, approximately equal tensile forces are generated in the individual partial tension members.

Various basic tests, investigation, suitability and acceptance tests prove that staggered load introduction into a composite body according to the multibond principle stabilizes the load transfer.

In complex and heterogeneous ground conditions within the grouted section, inhomogeneities of the ground are better compensated by multiple load introductions and stress peaks are distributed.

In compliance with the rules for design, execution and testing, BBV-multibond® staggered anchors can transfer significantly higher loads into comparable soils in a safe and plannable manner compared to conventional grouted anchors. If the boundary conditions are comparable, 2-fold and 3-fold loads generate a comparable safety level due to 2-fold and 3-fold activated shell surfaces.

The tripling of the test load has been successfully proven and executed for the BBV-multibond® staggered anchor system through various suitability tests and several hundred acceptance tests.

Thanks to the BBV Multibond®, costs can be reduced, construction times shortened and the sustainability of the project increased.

• With the same safety level, the staggering of the strands enables an increase (2-fold; 3-fold) of the anchor load-bearing capacity.

• Reduction of the number of anchors / anchor layers (possibly avoidance of anchor layer against pressing groundwater) [construction time + costs + sustainable conservation of resources].

• Reduction of intermediate excavation levels (dependent partial work steps: Producing supports / drilling levels / drilling / (post-)grouting / curing / testing / fixing / small-step partial excavation).

• Greatest positive impact on construction time! [construction time + costs+ sustainable resource conservation].

• Reduction drilling meters [construction time + costs+ sustainable resource conservation].

• Reduction of transports [costs + sustainable resource conservation].