Condon-Johnson and Associates (CJA) is recognized as the leading ground anchor contractor on the West Coast. CJA has a vast successful experience installing anchors for temporary excavation support, permanent retaining walls, landslide control, slope stabilization, marine bulkheads, marine tiedowns, and dam stabilization.
Tieback anchors (also called ground anchors) are pre-stressed structural elements used to transmit an applied tensile load into the competent soils in the bond zone. Tieback strands (or bar) consist of a high strength steel grouted into a drilled hole with a free stressing (unbonded) length and a bonded length. The unbonded length is the portion of the steel tendon that is allowed to elongate elastically and transfer the tensile load to the bond length. The bond length is where the tensile load is disturbed to the surrounding soils or rock to resist the loading. After the grout has reached 50% of design strength the tiebacks are stressed and locked off at a design load.
CJA has successfully installed tiebacks hundreds of feet deep with loads over 700 kips. Permanent tiebacks incorporate a corrosion protection system to increase the expected lift of the anchors in corrosive environments and/or when the anchors are permanent. Tiebacks can offer a cost-effective solution over cantilevered shoring solutions (when the excavation is greater than 13 feet) and can be installed when limited access limits construction methods.
For more information on CJA’s expertise, design/build options, and services for tieback and ground anchors please contact our nearest office location.