【正文】 irements Liquefaction settlement shall be totally eliminated, or liquefaction settlement is partially eliminated plus treatment to the foundation and superstructure D It is permissible not to take any provision It is permissible not to take any provision Treatment to the foundation and superstructure, or other economic provisions Building Layout and Structural Type Selection Antiseismic design specification for buildings GBJ 11 – 89 If a building with plicated shape is not provided with any antiseismic joint, its local stress and deformation concentration and torsion effect shall be estimated, and its portion likely to be damaged be determined, to take measures for better antiseismic capacity。 when antiseismic joints are provided, sufficient width shall be provided according to the intensity, ground class and building type, and the superstructures on both sides of the joint shall be pletely separated. All expansion joints and settlement joints shall ply with the requirements for antiseismic joints. An antiseismic structural system shall ply with all the following requirements: I. There shall be explicit calculation sketches and reasonable transmission route for the seismic actions。 II. Such consequences as damage to part of the structure or members resulting in the loss of antiseismic capacity or the bearing capacity of the gravitational force in the whole system shall be avoided。 III. It shall have necessary strength, good deformation ability and energy dissipation ability。 IV. Provisions shall be made to increase the antiseismic capacity at possible weak portions. — 4 — Structural Materials Antiseismic design specification for buildings GBJ 11 – 89 Any special requirement of the antiseismic structure on materials and construction quality shall be indicated in the design documents. The performance parameters of structural materials shall ply with the following minimum requirements: I. The strength grade of clay bricks shall be no lower than , and that of mortar for the brick masonry not lower than 。 III. The strength grade of concrete shall be no lower than C30 for frame beams, columns and nodes in case of antiseismic class I, no lower than C15 for structural columns, stems, girths and expanded foundations, and no lower than C20 for other types of members。 Design specification for concrete structures GBJ 10 – 89 In the design for antiseismic grades I and II, for the selection of longitudinal load bearing reinforcing bars in a frame structure, the measured strength value as obtained in the inspection shall also meet the following requirements: I. The ratio of measured tensile strength value to the measured yield strength value of the bars shall be no less than 。 II. The ratio of measured yield strength value of the bars to the standard strength value of the bars shall be no greater than for design with antiseismic grade I, and shall be no greater than for design with antiseismic grade II. Technical regulations on structural steel for highrise civilian buildings JGJ 99 – 98 The strength to yield ratio of antiseismic structural steel shall be no less than , and the elongation shall be greater than 20%. Seismic Action and Antiseismic Proof Calculation for Structures Antiseismic design specification for buildings GBJ 11 – 89 The seismic action of various types of building structures shall be taken into consideration according to the following principles: I. Under normal conditions, horizontal seismic action can be taken into consideration in both main axes directions of the building structure, and antiseismic proof calculation performed, the horizontal seismic action in each direction shall be fully undertaken by the antilateral force members in that direction。 II. In any structure with angular antilateral force members, the horizontal seismic action in the direction of each antilateral member shall be taken into consideration。 III. For structures with apparent uneven or asymmetric mass and rigidity distribution, the torsion effect of horizontal seismic action shall be taken into consideration。 IV. The vertical seismic action shall be taken into consideration for large span structures and long cantilever structures for intensity 8 and 9 degrees, and for highrise buildings for intensity 9 — 5 — degrees. In the calculation of seismic action, the gravitational load characteristic value of the building shall be taken as the sum of the standard value of the selfweight of the structure and members and accessories and the bined value of all the variable loads. The bined value coefficient of all the variable loads shall be taken from Table . Combined value coefficient Table Type of variable load Combined value coefficient Snow load Live load on roofing Not taken into consideration Live load on flooring considered according to actual conditions Live load on flooring considered as equivalent evenly distributed load Library store and archive store Other civilian buildings The seismic influence coefficient of building structures shall be taken as per Fig. on the basis of the near earthquake, far earthquake, site class and selfvibration period of structure, and its lower limit shall be no less than 20% of the maximum value。 in the sectional antiseismic proof calculation, the maximum value for horizontal seismic influence coefficient shall follow Table . Max. value for horizontal seismic influence coefficient in the sectional antiseismic proof calculation Table Intensity 6 7 8 9 amax Fig. Seismic influence coefficient curve a — Seismic influence coefficient。 amax — Max. value of seismic influence coefficient。 T — Self vibration period of structure。 Tg — Characteristics period, to be taken