hickness ratio for beams and column in the buil ing(GB50011-2010) and colum le 8.4 3.Slenderness ratie and width-thickness ratio of braces ed b Where,人-一 总s水当受 a5÷a6-n学腰心 he io of the hra ble 87 Limi tioo of width-th ess ratio for brace in CB ratio of brace in CB9 2、Width-thickness ratio of plates in beam and column For the sake of prevent from early local buckling which decrease the deformability of members, the width-thickness ratio shall be limited according to Table 8.4 and Table 8.5. Both two tables are based on Q235 steel and it should be times the factor of to the steel with different yield stress. 235/ ay f 85- 120Nb /(Af ） <=75 80- 110Nb /(Af )< =70 72- 100Nb /(Af )< =65 72-120Nb /(A f)<=60 webs of H and box section plates of box section 30 30 32 36 between two flanges flange of H shaped section 9 9 10 11 Beam and box section plates in box section 33 36 38 40 web of H shaped section 43 45 48 52 flange of H shaped section 10 11 12 13 Column Plate element Grade I Grade II Grade III Grade IV Table 8.5 Limitation of width-thickness ratio for beams and columns in the building(GB50011-2010) 3、Slenderness ratio and width-thickness ratio of braces At the section where plastic hinge is expected the brace should be set at both flanges of the member. The slenderness ratio of the laterally supported members shall meet the requirements decided by the following equations. 1 1 y px px y 235 While 1 0.5 (60 40 ) M M W f W f f - £ £ ，l £ - 1 1 y px px y 235 W 0.5 1.0 (45 10 ) M M W f W f f hile < £ ，l £ - （8.9a） （8.9b） Where， 1 1 y y y is the distance between the lateral support points is the radius of gyration about the out-of-plane axis of the section; l l i i l = － ， 1 1 the moment of the section where the lateral brace is connected, the value taken as positive if the bending moment in same direction among the range of ,or taken as nega M l - tive. ay 235/ f The slenderness ratio of the brace members in CBF structure shall not exceed the limitation listed in Table 8.6. And their width￾thickness ratio shall not exceed the limitation listed in Table 8.7. Both two tables are based on Q235 steel and it should be times the factor of to the steel with different yield stress. Table 8.6 Limitation of slenderness ratio of brace in CBF Building exceeding 12 stories 120 90 60 tensile member 200 150 150 designed as compressive member 150 120 120 designed as Building not exceeding 12 stories Plate element VI, VII VIII IX The width-thickness ratio of the brace members in CBF structure shall not exceed the limitation listed in Table 8.7. Both two tables are based on Q235 steel and it should be times the factor of to the steel with different yield stress. 235/ ay f Table 8.7 Limitation of width-thickness ratio for brace in CBF of pipe section 42 40 40 38 diameter￾thickness ratio 31 28 25 23 21 21 19 web of box section web of H section 33 30 27 25 23 23 21 13 11 9 9 8 8 7 outstanding flange VII VIII IX VI VII VIII IX Building exceeding 12 stories Building not exceeding 12 P stories late element