Braced frame structure and Frame with s oirt.are theoueh the same t Tube structures at both e ds or one en or a shor s20 .Structural systems of middle and high rise buildin on for building height 五 of the 4 2.Braced frame structure and Frame with shear wall 支撑 支撑 支撑 The main components to resist horizontal earthquake action are the bracing or shear wall. The braced frame structure system can generally divided as concentrically braced frame (CBF) and eccentrically braced frame (EBF). Plan Profile Concentrically braced frame (CBF) ：The central lines of the members: column, beam and brace, which are connected in one joint, are through the same point . Figure 8.8 Concentrically braced frames a) X type b) inverted V type c) V type d) K type e) and f ) diagonal type a) b) c) d) e) f) Eccentrically braced frame (EBF) ：The eccentricity can be arranged in different ways, for example, the brace is shifted from the joint center at both ends or one end, or a short cantilever hung from the beam. a) a a a a a a a b) a a a a a a a a c) a a a a a d) a a a a a the segment marked ‘a’ is called ‘link’ in EBF, which is the main component for energy dissipation. Figure 8.10 Types of eccentrically braced frames 3. Tube structures To the buildings which height exceeds 200 meters, tube structures, mega frame structures are considered more suitable. Plan Plan Profile Figure 8.6 Sections of structures for middle and high rise buildings (a) moment resisting frame (b) braced frame (c) tube structure (d) braced frame tube (e) mage structure 8.2.1 Structural systems of middle and high rise buildings a ) b ) c ) d ) e ) 1. Limitation for building height 2. Limitation for height-width ratio 8.2.2 Requirement for arrangement of steel structural systems (GB50011-2010) tube and mega structure 300 280 180 Concentrically braced frame 220 200 120 frame 110 90 50 IX (0.40g) VII (0.15g) VI, VII (0.1g) Structural systems eccentrically braced frame 240 220 160 VIII 90 180 200 260 (0.20g) (0.30g) 70 150 180 240 Limitation of the ratio 6.5 6.0 5.5 Design intensity of the region VI, VII VIII IX