Epoxy Anchors

SPECIAL INSPECTION, CONTINUOUS – The inspection of construction or work that requires special inspection in accordance with the statement of special inspections and, due to the nature of the work, is inspected by an approved special inspector who is continuously present in the area when and where the construction or work is being performed.

SPECIAL INSPECTION, PERIODIC – The inspection of construction or work that requires special inspection in accordance with the statement of special inspections and, due to the nature of the work, is inspected by an approved special inspector who is intermittently present in the area when and where the construction or work has been or is being performed.

The statement of special inspection is submitted by the Engineer of Record (EOR) and is made part of the building permit. Special inspectors are approved on the basis of criteria established by the authority having jurisdiction (AHJ), which may be a city, country, or state agency. See Section 2.4 for additional information. 

2.4 Qualification of Special Inspectors

A special inspector is a specially qualified person with both inspection and practical experience in the construction operation requiring special inspection. The individual must submit his qualifications to the local building official for approval. Approval is sometimes done on a case by case basis or is granted to local testing agencies who employ inspectors with the particular expertise. In many cases the approval is informal, based on previous experience with firms and individuals. The International Code Council (ICC) has a certification program that includes many of the common special inspections. Also International Accreditation Service (IAS) has an accreditation program for special inspection agencies. Engineers may be qualified as special inspectors, however an engineering degree or license does not automatically qualify a person as a special inspector.

2.5 Employment of Special Inspectors

Section 1704.1 of the 2009 IBC states the following:

1704.1 General. Where application is made for construction as described in this section, the owner or the registered design professional in responsible charge acting as the owner’s agent shall employ one or more approved agencies to perform inspections during construction on the types of work listed under Section 1704. 

Thus it is the owner of the construction project or the engineer or architect of record, acting as the owner’s agent, that employs the special inspector(s). Contractors may not employ the special inspector(s), since this would constitute a conflict of interest and is not in accordance with the intent of special inspection as an independent evaluation. 

2.6 Duties and Responsibilities of Special Inspectors

The special inspector observes the work for conformance with the approved design drawings, specifications and workmanship provisions of the building code, brings discrepancies to the immediate attention of the contractor and to the design authority and the building official if not corrected. Periodic and final inspection reports are required to be submitted to the building official and engineer or architect of record.

The special inspector is considered an extension of the building official by virtue of the code requirements for inspections by the building official and special inspection. The City of Los Angeles formalizes the relationship with special inspectors in this regard, and they are called “deputy inspectors”. 

3.0 Special Inspection Requirements for Post-Installed Anchors

Table 1704.4 of the IBC provides special inspection requirements for concrete construction. Anchors installed in hardened concrete are listed as requiring periodic special inspection. The inspection level for cast-in anchors for which the higher allowable loads in the code were used was continuous. In the 2009 IBC, the inspection requirement was broadened to all cast-in anchors designed in accordance with the strength design procedures of ACI 318 Appendix D. In the 2012 IBC, this requirement was reduced to periodic inspection due to the similarity with special inspection of reinforcing steel. 

4.0 Special Inspection Procedures

     4.1 General

Visual special inspection of cast-in anchors is conducted prior to concrete placement. Special inspection of post-installed anchors can occur both at the time of anchor installation and subsequent to anchor installation (e.g., for proof loading).

     4.2  Special Inspection of Cast-in Anchors

Where required by the building code, cast-in anchors are included in the Statement of Special Inspections and are inspected together with other elements in the formwork such as reinforcing bar placement. To meet the requirements of continuous inspection when special inspection is specified, the special inspector must verify that the installation is in accordance with the requirements of the approved plans, evaluation report and manufacturer’s instructions. This generally means verifying the location of the anchor including any edge distance and spacing requirements, as well as anchor type, size, and embedment.

     4.3 Special Inspection of Post-installed Anchors

The inspection requirements for post-installed anchors are generally derived from the manufacturer’s published installation instructions (MPII) and from the relevant evaluation report (ICC-ES ESR or other) for the product. Typical inspection procedures consist of reviewing the type of anchors that will be installed prior to the commencement of work and determination of what aspects of the installation are critical from an inspection standpoint. This varies from anchor type to anchor type. Generally, inspection focuses on verification that the anchor is in accordance with the project specifications, that the installation procedure is in accordance with the MPII, and that the anchor size, placement and embedment are in accordance with the contract documents.

Where required by the contract documents, procedures to avoid existing reinforcing bars in the concrete during drilling are reviewed by the inspector. Where core drilling is used, this is particularly important. Measures to be taken if reinforcing bars are encountered or damaged may include relocation of the anchor and will usually involve consultation with the EOR.

          4.3.1 Post-installed Mechanical Anchors

The special inspector must verify that the installation is in accordance with the requirements of the approved construction documents, applicable evaluation report and the MPII, including verification of the location of the anchor, edge distance and spacing requirements. Pre-installation inspection of post-installed mechanical anchors usually consists of verification of anchor type, material, size and length, drilling method, drill bit type and size, hole cleaning procedures, and anchor installation and setting procedures. Special attention to aspects of the installation may be required depending on the job conditions. For example, where anchors installed in a slab on grade, it may be necessary to check that the hole drilling procedures do not result in breaking through to the underside of the slab. Use of a properly calibrated torque wrench is required for setting of many types of anchors, and is also required to avoid over-torquing of anchors during subsequent assembly. Prior to application of torque, anchor threads are inspected for damage or fouling. During setting of torque-controlled expansion anchors, the inspector will note the number of full turns required to achieve the required torque. Where anchors fail to set within the maximum permitted number of turns, procedures to remove and replace the anchor are developed with the EOR. Where large numbers of anchors are being installed, the inspector may observe the initial installations continuously, and thereafter perform periodic inspections as the installation proceeds. Subsequent continuous inspection of the installation for a time is required where there is a change of personnel performing the installation or where the anchor type is changed. ICC-ES acceptance criteria include a requirement for a length identification letter code to be stamped on the ends of anchors recognized for multiple embedments (usually wedge anchors). This makes it possible for the special inspector to determine, in conjunction with a knowledge of the specific anchor make, the embedment of these types of anchors after they have been installed. 

Verification of proper set is conducted according to the anchor type. Torque-controlled expansion anchors such as wedge anchors and sleeve anchors are generally checked by application of torque with a calibrated torque wrench. Drop-in anchors (displacement controlled expansion anchors) are checked by placing the setting tool into the anchor body to verify full set prior to installation of the bolt or threaded rod. Undercut anchors generally incorporate a method of visual verification of full set (full engagement of the anchor in a fully-developed undercut). Verification of proper set of screw anchors is performed during installation by ensuring that the minimum torque resistance is achieved, that the maximum torque is not exceeded, and that the anchor has achieved the required embedment.

Where specified, proof loading of mechanical anchors may be conducted by placing a loading shoe under the anchor head or threading a coupler onto the anchor stud. Proof loading of screw anchors may be performed in the case of anchors that have been prequalified for re-setting, however this must be approached with caution since testing may damage the screw threads in the concrete. 

          4.3.2 Adhesive anchors

The special inspector must verify that the installation is in accordance with the requirements of the approved construction documents, applicable evaluation report and the MPII, including verification of the location of the anchor, edge distance and spacing requirements. Pre-installation inspection of adhesive anchors usually consists of verification of anchor type, material, size and length, drilling method, drill bit type and size, hole cleaning procedures, and anchor installation and setting procedures. In addition, the inspector must verify the expiration date of the adhesive and the manner in which it has been stored. Anchor elements (threaded rod, reinforcing bars, internally threaded sleeves) must be inspected for the presence of substances that might interfere with bond (e.g., dust, mud, oil) and that the threads are undamaged and not fouled. Reinforcing bars must be free of loose rust. In cases where the concrete temperature may be higher or lower than normal room temperature, the concrete temperature in-situ must be verified prior to installation for conformance with the requirements of the MPII and to establish the cure time for the adhesive.

Since the design bond strengths for adhesive anchors are often associated with the use of specific drilling techniques (based on the resulting hole roughness), it is important that the specified hole drilling technique is used.

Verification of hole cleaning procedures in accordance with the MPII is critical. Where holes are drilled and cleaned in advance of anchor installation, it must be verified that the holes are protected from intrusion of contaminants or moisture (e.g., rainwater) during the interim period, or that the cleaning steps are performed immediately prior to anchor installation.

Prior to anchor installation, hole depths must be verified to ensure the correct embedment and to determine, in the case of injection systems, that the correct amount of adhesive is dispensed into the hole.

Injection adhesive systems have special requirements to ensure that the adhesive injected is correctly metered and mixed. These usually include, for each new cartridge, dispensing a quantity of adhesive from the mixing nozzle prior to beginning injection of adhesive in the hole. The objective of adhesive injection is to avoid entrained air. For long holes and holes drilled horizontally or overhead, the MPII may specify special equipment such as extension tubes, stoppers and end caps to achieve a void-free injection. The presence of air bubbles in the adhesive may be detectable as a tendency of the anchor element to spring back after being pushed into the adhesive mass or a popping sound is heard as air bubbles are displaced upward. Inspection of the installed anchor includes verifying that the anchor position is true (angle with respect to the concrete surface), that the anchor is secured against movement during the cure time, and that adhesive has not fouled the threads.

The inspector should verify that personnel performing adhesive anchor installation are experienced and qualified to use the specific adhesive anchor system being employed. ACI 318-11 Appendix D requires that all horizontal and upwardly inclined installations of adhesive anchors that resist sustained tension must be performed by certified adhesive anchor installers. A certification program is offered by ACI that includes both written and performance components.