Anchor Pull-Out Test for Concrete, Masonry & Rock

The anchor pull-out test is a central method for verifying the load-bearing capacity of fixings in concrete, masonry, and rock. In the context of concrete demolition and specialized deconstruction, strip-out and cutting, rock demolition and tunneling, as well as natural stone extraction, it ensures that temporary and permanent anchorages reliably take up the intended loads. This is particularly relevant when components are released with concrete pulverizers, separated in a controlled manner with hydraulic rock and concrete splitters, or when component segments are temporarily secured during cutting. The anchor pull-out test thus combines practical safety with robust quality assurance on the construction site and in underground works.

Definition: What is an anchor pull-out test

An anchor pull-out test is an on-site tensile test in which a single installed anchor (mechanical or chemical) or a rock/rock-bolt anchorage is subjected to a defined tensile load. The aim is to demonstrate that the connection of anchor, base material, and installation safely carries the required load and that deformations (slip) remain within permissible limits. The test is performed with a reaction bridge or reaction foot, a hydraulic cylinder, a pump, and a calibrated measuring device. Depending on the purpose, common test types include suitability tests during work preparation, acceptance tests during execution, and spot checks. Assessed are load–displacement behavior, failure mode (e.g., pull-out, concrete breakout, steel failure), and achieving the specified test load without inadmissible settlement.

Areas of application and typical use cases

The anchor pull-out test is used whenever temporary or permanent fixings must safely transfer loads. These include:

Concrete demolition and specialized deconstruction: Testing of attachment points and holding anchors that secure components or guide loads when working with concrete pulverizers, combination shears, or steel shears.
Strip-out and cutting: Verification of tension anchors for support structures, anti-tilt and anti-lift safeguards during sawing and separation, including in reinforced or high-strength concrete.
Rock demolition and tunneling: Verification of anchors and rock bolts that stabilize excavation faces or secure the work area when rock and concrete splitters are used for controlled rock separation.
Natural stone extraction: Testing of anchorages on raw blocks and exposure faces when blocks are moved or separated in a controlled manner.
Special use: Temporary fixed points for guide rails, work platforms, catch and protection structures, or provisions prepared for deconstruction.

Process and on-site test procedure

The procedure depends on the base material, anchor type, and required verification. In practice, a structured sequence has proven effective.

Preparation of the base material

Create, clean, and prepare the borehole in accordance with the fixing system specifications (drill diameter, hole depth, cleaning technique).
Install the anchor: mechanical expansion or chemical bonding, complying with edge distances, spacing, and embedment depth.
Observe curing times (chemical systems) and document ambient conditions (temperature, humidity, base material strength).

Setup of the test equipment

Position the reaction bridge or foot so that the load is introduced centrally into the anchor without overloading edge regions.
Connect the hydraulic cylinder with a calibrated display (pressure gauge or load cell); check for tightness and proper function.
Position a dial gauge or displacement transducer to record settlement.

Applying the tensile load

Preload stage: Low preload to check settlement and positioning.
Stepwise load increase: In defined increments up to the test load; each step with hold time and displacement reading.
Assessment: Was the test load reached? Are deformations within permissible limits? Observe and document the failure mode.

Documentation and assessment

Record anchor data (type, size, embedment length), base-material data (concrete compressive strength class, rock type), edge distances, and borehole quality.
Log load steps, hold times, deformations, and the final result (passed/failed).
Photo documentation of the test setup and the reaction arrangement.

Equipment and accessories

Suitable test equipment is crucial for reproducible results. Common are pull-test devices with hydraulic drive, reaction bridges with variable spans, adapters for different threads and anchor heads, and calibrated measuring instruments. hydraulic power units provide the necessary energy for the tensile loading and enable finely metered load increases. In environments with confined space, as often encountered in selective deconstruction or tunneling, compact, hand-held systems with a short reaction chain are advantageous.

Influencing factors on capacity and test result

Base-material quality: Strength, homogeneity, cracking, and moisture significantly affect load transfer.
Edge and spacing distances: Too small distances promote concrete breakout and reduce capacity.
Borehole and installation quality: Inadequate cleaning, incorrect drill diameter, or faulty installation lead to slip and failure.
Curing times and temperature: Chemical systems require sufficient time; temperatures influence resin reaction.
Load-axis alignment: Eccentric loading distorts results and can cause local overloads.
Corrosion and aging effects: For existing anchors, condition and history must be considered.

Typical failure patterns and their causes

Pull-out without concrete breakout: Often due to insufficient bonding, too little embedment depth, or contaminated boreholes.
Cone-shaped concrete breakout: Frequent with small edge distances, low concrete strength, or high loads.
Steel failure: Indicates high steel stress with a simultaneously capable base material.
Sliding or settlement with permanent slip: Installation errors, insufficient curing, or dynamic effects.

Planning, test scope, and load level

Before starting work, the number of test points, test loads, and evaluation criteria are defined. Common are spot checks of representative anchor groups as well as increased test rates at critical locations (e.g., edge regions, varying base materials). The test load is based on the intended service load level and the governing safety reserves. For chemical and mechanical anchors, the manufacturers’ specifications and applicable technical rules are decisive, and project-specific provisions should always be documented.

Practical relevance: Interaction with concrete pulverizers and rock and concrete splitters

When components are released in a controlled manner using concrete pulverizers, attachment and holding points are needed to guide, secure, or position parts. Here the anchor pull-out test shows its strength: Capable fixed points enable the safe separation and lowering of segments, minimize vibrations, and reduce uncontrolled fracture edges. Similarly, when using rock and concrete splitters: the expansion of borehole wedges generates forces that redistribute through the structure. Verified anchorages serve as retention or bracing points to steer crack propagation or stabilize work areas. In rock advance and tunneling, verified anchoring likewise supports the safe sequence of drilling, splitting, securing, and mucking.

Safety, occupational safety, and quality assurance

Cordon off the test area, protect against falling parts, and comply with personal protective equipment.
Regular calibration of measuring devices; visual inspection of the reaction bridge and hydraulic components before each use.
No overloading beyond the specified test load; controlled pressure release after each load step.
Documented release of tested anchors before they are used as attachment or safety points.

Documentation and verification

Complete documentation provides legal certainty and supports execution. At a minimum, record: location plans of tested anchors, anchor type and dimensions, base-material description, installation and cleaning record, equipment calibrations, load steps with hold times, displacement values, failure mode, and result. For site management and supervision, traceable, sequentially numbered test reports with date, personnel, weather, and boundary conditions are useful.

Relation to other work equipment

In addition to concrete pulverizers and rock and concrete splitters, other tools are frequently used in practice whose safe use relies on verified anchorages: Multi Cutters and steel shears for cutting reinforcement, combination shears in selective deconstruction, tank cutters for deconstruction-ready work on vessels, as well as power units to supply energy to test and work equipment. The anchor pull-out test provides a robust foundation for this.

Checklist for a practical anchor pull-out test

Define test objectives and scope; identify critical areas.
Assess base material and select suitable anchors; plan edge distances and spacing.
Perform drilling and installation according to specifications; observe curing times.
Set up the test device, check calibration, center the reaction bridge.
Apply load steps with hold times, measure and log deformations.
Evaluate the result, document the failure mode, and derive corrective measures if necessary.
Release anchors for the intended purpose only after a passed test.

Quality in the project workflow

Early integration of the anchor pull-out test into work preparation accelerates processes, reduces rework, and increases safety—especially where components are released with concrete pulverizers, separated in a controlled manner with rock and concrete splitters, or selectively removed in sensitive environments. This creates a consistent sequence of planning, testing, and execution that makes load paths transparent and maintains the effectiveness of the methods used.