5.1.3Configuration Influences on Seismic Performance 5.1.4 Essentials of Structural System The desig ch 1.Sclectionof materialsand types of construction abers on the perimteter whenever possibl is 二e情ge 回 回 Better ·Reasonable cost 2.Major Characteristics of Building structures Summary Requirements for seismic structural system and rein rete composite structures en structure cast co e stru 7 7 2.The structure with vertical irregularity • The story shear force of the soft/weak story must be increased by 15%. • The elasto-plastic analysis must be conducted for the tall building exceeding the specified height. • The shear strength of the weak story should not be less than 65 percent of that of the adjacent upper story for the structure with abrupt change of story carrying capacity. 3. The structurewith both plan irregularity and vertical irregularity • The above two terms must be followed simultaneously. • In addition, for the structure with seriously irregularity, time history analysis must be carried out to check the analytic results obtained by modal analysis. • For the building with seriously irregularly configuration, seismic joints can be provided to separate the building into simple and regular individual units. There must be enough clearance at the seismic joints so that the adjoining portions do not pound each other. • The design characteristic of redundancy plays an important role in seismic performance. • Placing resisting members on the perimeter whenever possible is always desirable. • The detailing of connections is a key factor in seismic performance, since the more integrated and interconnected a structure is the more load distribution possibilities there are. • The lower of the density center of a building, the better resistant performance. 5.1.3 Configuration Influences on Seismic Performance Better 5.1.4 Essentials of Structural System 1. Selection of materials and types of construction • Structural materials have their own performance characteristics and should be selected according to the location and condition of the building to be planned in order to accomplish safe, economical, and superior architecture. • High strength-to-weight ratio • High deformability • Low degradation • High uniformity • Reasonable cost • Steel structures • Steel and reinforced-concrete composite structures • Wooden structures • Cast-in-situ reinforced concrete structures • Precast concrete structures • Prestressed concrete structures • Masonry structures • Mixed structures 2. Major Characteristics of Building structures Requirements for seismic structural system 1. It shall have a clear analytical model and reasonable path for seismic action transfer. 2. It should have several lines of defense against earthquakes. It should avoid loss of either earthquake resistance capacity or gravity load capacity of the whole system due to damage to part of the structure or members. 3. It shall possess the necessary strength, adequate deformability, and better energy dissipation ability. Summary