【正文】 ix , iy =coordinate x (y) distance from anchor i to the center of the anchor group. The design value of shear loads acting on an individual anchor of an anchor group under the bined shear load V and torsion moment T shall calculated by the following formulas (see Fig. ): ? ? ? ?2,2, T ysiV ysiT xsiV xsisi VVVVV ???? () max,sihSd VV ? () SiV =the design value of shear load acting on anchor i Fig. Torsion moment – 26 – 6 Ultimate limit state Resistance to tension loads The resistance to tension loads shall be checked according to Table : Table required proof failure mode single anchor anchor group steel failure sRdSd NN ,? sRdhSd NN ,? Pull th。 TxSiV, , TySiV, = the shear loads in x (y) direction acting on anchor i of an anchor group under the torsion moment acting on the fixture。 VSi =the bined shear loads acting on anchor i of an anchor group under shear load V on the fixture。iy = perpendicular distance from anchor 1(anchor i) to the outermost edge anchors L =distance from the acted point of normal force N to the outermost anchors in the pressed area. Tension loads acting on Anchor group For the distribution of shear loads and torsion moments acting on the fixture to the anchors of a group anchor the following case shall be distinguished based on the diameter of drilled holes of anchor plate, fd , and the diameter of anchors,d , the Fig. centralized tension load Fig. bined tension and shear loads – 23 – distance c from anchors to the edge of concrete member. 1. All anchors take up shear loads if the hole clearance between anchor stud and drilled holes on anchor plate, ddf ??? , or the clearance between the drilled holes and sleeve of anchors nomf dd ??? , is not greater than the acceptable value ??? in Table and the edge distance is larger than 10 efh (see Fig. ): Table diameter of clearance hole in the fixture (mm) External diameter d or nomd 6 8 10 12 14 16 18 20 22 24 27 30 Diameter fd of clearance hole in the fixture 7 9 12 14 16 18 20 22 24 26 30 33 maximum clearance??? 1 1 2 2 2 2 2 2 2 2 3 3 2. Only the most unfavorable anchors take up shear loads if the edge distance is smaller than 10 efh ( efhc 10? ) or the hole clearance is larger than the value given in Table ( ? ???? )(see Fig. )。 hsdN =design value of tension load acting on the most stressed anchor in an anchor group. 1y , iy =perpendicular distance from anchor l (anchor i) to geometrical center of an anchor group 39。 N = design value tension load resisted by an anchorage group。 2. The anchors do not contribute to the transmission of pression force (except for bonded anchors and rebar), so the pression force is transmitted by anchor plate to the concrete directly. 3. Internal force of anchor shall be calculated according to the theory of elasticity. If the anchorage failure of anchors or bonded anchor/rebar is steel failure and the strength of the steel is low (? grade), the internal force shall be calculated according to the theory of elasticityplastic theory considering stress redistribution. If the condition in Equation is fulfilled, then noncracked concrete shall be assumed, otherwise cracked concrete shall be assumed, and the width of crack shall be calculated according to Code for Design of Concrete Structures: 0?? RL ?? () L? =characteristic value of stress produced by external actions and prestressed force in concrete member. The positive is tension, negative is pression。 S = design bined loads of anchorage, calculating according to Code of Building Structure Loads and Designing Code for Antiearthquake. R , kR = design(characteristic) resistance strength of anchorage。 and a) Load controlled anchor installed by tensioning anchor, causing sleeve to expand in predrilled undercut d) Displacement controlled anchor that cuts its own undercut while set by hammering sleeve over cone b) Displacement controlled anchor set in predrilled undercut by hammering sleeve over cone. e) Torquecontrolled anchor set into pre drilled undercut by application of torque forcing sleeve over cone c) Displacement controlled anchor installed in predrilled undercut and set by defined displacement, causing expansion sleeve to expand into undercut. f) Torquecontrolled anchor that cuts its own undercut by application of setting torque, forcing sleeve over cone. – 6 – ? Printed instructions for the adhesive anchor installation including hole preparation, injection, and cure for all environmental conditions permitted in the qualification. Fig Adhesive anchor / rebar Base material The hardened material into which anchor is fastened. Normal weight concrete is defined to as the base material in this standard. Anchor Group A number of anchors of approximately equal effective embedment depth with each anchor spaced at less than 3hef from one adjacent anchor when subjected to tension, or 3ca1 from one or more adjacent anchors when subjected to shear. Only those anchors susceptible to the particular failure mode under investigation shall be included in the group. Fixture Component fixed to the concrete via the postinstalled anchoring system. Anchor plate A steel plate fastened by anchors directly transfer loads onto anchors and base material. Failure mode The failure mechanism observed of postinstalled anchoring system post peak loads. – 7 – Anchor steel failure The steel failure of anchor rod or rebar under tension, shear or bined tension and shear (see Fig ). Tension