Development and validation of European guidelines for seismic qualification of post-installed anchors

Abstract

This paper presents the technical background for the seismic qualification procedures for post-installed anchors in the European Technical Approval Guideline (ETAG 001) seismic annex issued in 2013. We discuss requirements for a comprehensive guideline and reference supporting documentation. Numerical studies to generate new simulated seismic protocols for anchors are summarized with focus on their application to Europe. To reduce the time and cost of anchor product qualification testing while fulfilling the requirement of European building codes to assess two performance categories, we combine the results of our numerical studies to generate novel testing protocols that allow for the assessment of anchor behavior at multiple levels in a unified protocol. Validation tests demonstrate that the unified protocol results in anchor performance comparable with that achieved in multiple, single-performance-level tests.

Shear Strength of an Anchor Post-Installed into a Hardened Concrete Member

“…On the contrary, [73] drastically underestimates the shear strength of small diameters and drastically overestimates the shear strength for large diameters, and above all, drastically misestimates the shear strength of the anchors whose failure is dictated by the crushing of the surrounding concrete. The flaw stemming from small and large diameters, which is due to the empirical nature of the formulation, is something that both researchers and practitioners are already very well aware of and has also been pointed out previously in literature [84]. The flaw stemming from concrete crushing failure mode, which is due to a formulation that ignores the contact pressures, has not been pointed out before, although ignoring it can lead to unsafe predictions.…”

“…The concrete anchor is also dealt with by many codes, standards, reports, and test methods edited by organizations for technical assessment and by technical committees [72][73][74][75][76][77][78][79][80][81][82][83]. However, the technical literature follows the scientific literature [84,85]. Accordingly, those documents mainly focus on cast-in anchors, pull-out strength, combined tension and shear, concrete edge failure, anchor group effect, and anchor's shaft failure.…”

“…That gap in scientific and technical literature implies that the shear strength of a post-installed concrete anchor cannot be predicted at the design stage but must be measured on-site by tests at the construction stage. Indeed, the only topic related to concrete anchors that is broadly covered by the scientific literature is the definition of testing procedures [7,10,11,13,14,26,31,35,50,68,[70][71][72][73][74][75][76][77][78][79][80][81][82][83][84][85], and the only topic sufficiently covered by codes and recommendations is the standardization of methods to test anchors for use in concrete [72][73][74][75][76][77][78][79][80][81][82].…”

Behavior of Anchors Embedded in Concrete Damaged by the Maximum Considered Earthquake: An Experimental Study

“…Cracking of anchor embedment zones is the most conservative case. Several studies substantiate the likelihood of cracks occurring in anchor installation zones [21][22][23]. According to [21], post-earthquake values of residual crack opening width in reinforced concrete elements reach up to 1.04 mm in opening width.…”

Pullout tests on the connection to an existing foundation of a steel warehouse rebuilt after the 2012 Emilia (Italy) earthquakes

“…These findings flowed into the seismic qualification procedure and design method reported by EOTA (European Organisation for Technical Assessment) 2013a, b; 2016b). The technical basis for the seismic qualification of anchors were recently summarized by Mahrenholtz et al (2017b), which also proposed a unified testing protocol for the assessment of anchors at multiple performance levels.…”