Overview
What Are Tieback Anchors?
Tieback anchors — also called ground anchors or tiebacks — are post-tensioned steel tendons drilled and grouted into the ground behind a retaining wall or shoring system. Once the grout cures and develops bond strength, the anchor is stressed to a specified design load and locked off against the wall, providing active lateral support that resists earth pressure and prevents wall movement.
Rocky Mountain Micropiles drills, grouts, and stresses tieback anchors for soldier pile walls, sheet pile walls, concrete retaining walls, and slope stabilization projects. Every anchor is proof-tested to at least 133% of design load per PTI (Post-Tensioning Institute) specifications before lock-off — providing verified performance, not just calculated capacity.
Tiebacks are the standard solution when excavation depths exceed cantilever limits — typically 12’–15′ for soldier piles — or when wall deflection must be minimized to protect adjacent structures, utilities, and roadways.
Technical Data
Tieback Anchor Specifications
Key technical parameters for our ground anchor systems. Actual design values are project-specific and determined by structural and geotechnical analysis.
Hole size selected to accommodate the tendon, centralizers, and grout column needed to develop required bond capacity in the anchor zone.
Working loads typically range from 50–200+ kips per anchor depending on strand count, soil/rock bond capacity, and wall design requirements.
Total anchor length includes an unbonded free length through the active zone and a bonded zone grouted into competent soil or rock beyond the failure plane.
Multi-strand tendons using 0.6″ diameter, 270 ksi prestressing strand. Strand count (typically 2–7) selected to match the required design load with appropriate safety factor.
Every production anchor proof-tested to at least 133% of design load per PTI specifications. Performance and verification tests to 150% available on critical anchors.
Temporary anchors for construction-phase shoring or permanent anchors with double corrosion protection — encapsulation plus grout — for 75+ year design life.
Applications
Where Tieback Anchors Are Used
Tiebacks provide active lateral support for retaining structures that can’t resist earth pressures through cantilever action alone — typically excavations deeper than 12’–15′ or walls where deflection must be tightly controlled.
Discuss Your ProjectDeep Excavation Support
Multi-level tieback systems for deep commercial excavations where soldier pile or sheet pile walls need lateral support at one or more elevations to limit deflection.
Retaining Wall Reinforcement
Adding tieback capacity to existing retaining walls showing signs of distress, tilting, or displacement — restoring stability without full wall replacement.
Slope Stabilization
Ground anchors drilled through failure planes to stabilize active or potential landslides. The post-tensioned load provides immediate resisting force against slope movement.
Dam & Spillway Anchoring
High-capacity permanent anchors for dam stabilization, spillway structures, and hydraulic structures requiring resistance to uplift and overturning forces.
Adjacent Structure Protection
Where wall deflection must be minimized to protect neighboring buildings, utilities, or roadways. Tiebacks provide pre-loaded support that limits movement before it starts.
Bridge & Highway Infrastructure
Permanent tieback systems for bridge abutment walls, highway retaining walls, and MSE wall reinforcement on UDOT and municipal transportation projects.
Installation
Tieback Installation Process
Each anchor follows a controlled sequence from drilling through proof testing, with every step documented for the project record.
Drill Anchor Hole
Drill through the wall face plate at the specified angle (typically 15°–30° below horizontal) to the design depth. Casing used in unstable soils to maintain hole integrity.
Insert Tendon
Multi-strand tendon with centralizers and sheathing is inserted into the hole. Unbonded length is sleeved to allow free movement during stressing. Bond length is left exposed for grout contact.
Grout Anchor Zone
Neat cement grout is pumped under pressure from the bottom up, filling the bond zone and encapsulating the tendon. Grout mix design is matched to ground conditions and bond requirements.
Stress & Test
After grout reaches required strength, hydraulic jack stresses the anchor in increments to 133% of design load (proof test). Movement and pressure are recorded at each increment per PTI standards.
Lock Off & Document
Anchor is locked off at design load using wedges in the anchor head. Excess strand is cut and capped. Complete test data — pressures, movements, and acceptance criteria — is submitted to the engineer of record.
Comparison
Tiebacks vs. Alternative Lateral Support
System selection depends on excavation depth, deflection limits, access behind the wall, and whether the support is temporary or permanent.
Tiebacks vs. Internal Bracing
Bracing obstructs the excavation interior, complicating foundation work and material handling. Tiebacks keep the excavation completely open, allowing unrestricted access for foundation construction and equipment movement.
Tiebacks vs. Soil Nails
Soil nails are passive (not pre-stressed) and allow more wall movement before engaging. Tiebacks are actively loaded and provide immediate support at lock-off, making them preferred where deflection tolerance is tight or where adjacent improvements must be protected.
Tiebacks vs. Cantilever Walls
Cantilever soldier piles are economical for shallow excavations (under 12’–15′), but deflection increases rapidly with depth. Adding tiebacks allows the same pile section to support much deeper excavations with controlled deflection.
Tiebacks vs. Deadman Anchors
Deadman anchors require significant excavation behind the wall to bury the anchor block. Drilled tiebacks need only the drill hole, making them practical in tight sites, urban environments, and locations where excavation behind the wall isn’t feasible.
Featured Project
Multi-Level Tieback System, Wasatch Front
Rocky Mountain Micropiles installed a two-level tieback system for a 30’+ deep commercial excavation supporting a soldier pile shoring wall. Anchors were drilled and grouted into competent sandstone, then stressed and proof-tested to 133% of the 120-kip design load. The system was designed to limit wall deflection to less than 1″ to protect an adjacent occupied building and active utility corridor. All anchors accepted on first test with zero re-drills.