###### Abstract  
Fire design of cast-in place and post-installed anchors in concrete under fire is covered by EN 1992-4, Annex D, allowing steel- and concrete-related failure modes of anchors to be calculated. This informative annex of EN 1992-4 is limited to cast-in place or mechanical anchors, whereas post-installed adhesive anchors remain out of its scope. This paper presents a study of the applicability of the more flexible resistance integration method (RIM), proposed originally for the design of the pull-out resistance of post-installed reinforcement (PIR) by [PERSON], on bonded anchors in uncracked concrete. This method is validated from a comparison of test results obtained from two research projects conducted at CSTB and TU Kaiserslautern on bonded anchors in uncracked concrete under ISO 834-1 fire conditions. The data considered include tests conducted on anchor sizes from M8-M30 using three different adhesives (two epoxy adhesives and one cementitious mortar). Design of the pull-out resistance under fire using RIM requires numerical calculation of temperature profiles considering models of concrete and steel elements; different assumptions about modeling these elements can produce vastly different end results. Finally, recommendations for assessment procedures for bonded anchors under fire conditions are provided as entry data for design. adhesive resin; bonded anchor; fire tests; thermal distribution; numerical model +
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properties of adhesive resins are particularly temperature dependent [11]. Under fire conditions, research studies [12; 13] have shown that bond failure occurs more frequently than other failure modes for common ranges of bonded anchor diameter and embedment due to exceedance of glass transition temperatures and material softening. As with other sensitivities, use of bonded anchors in cases where fire ratings are required must be accompanied by proper assessment and design procedures. Current assessment and design guidelines do not offer evaluation and design methods for bonded anchors under fire conditions [7; 14]. Existing guidelines in the European Assessment Document (EAD) 330087 [15] for post-installed reinforcement (PIR), however, provide criteria to produce bond stress vs. temperature curves for adhesives at high temperature expected during fire events. In these guidelines, a temperature response curve is obtained by a minimum of 20 tests on 12 mm diameter reinforcing bars installed with 120 mm embedment depths in confined concrete cylinders. After curing of the adhesive, tests are subjected to different magnitudes of constant load and increasing temperature until failure. The resulting curve allows design of PIR under fire conditions using [PERSON]'s bond strength resistance integration method (RIM) [16]. The load-bearing capacity of the PIR connection is calculated using temperature profiles along the embedment depth for fire design, which is normally determined through numerical calculation. Using the bond stress vs. temperature curve of the adhesive, resistance contributions associated with the temperatures along the length of the connection can be integrated into an overall connection-resistance specific to temperature profiles. For standard fire conditions where the required capacity and temperature distributions during fire exposure are known, the time to failure of the connection can be calculated. The steps of the resistance integration method were established first by [PERSON] et al. [16] and validated on a large-scale test at the fire resistance laboratory at the Centre Scientifique et Technique du Batiment (CSTB) on cantilever-wall connection using PIRs under ISO 843-1 fire conditions [17]. Another large-scale validation was performed at CSTB on a slab-wall connection under ISO 843-1 fire conditions by [PERSON] et al. [18]. [PERSON] et al. [19] also proposed a non-linear shear-lag model taking into account the displacement compatibility of PIR at high temperature (unaccounted for in RIM).