Seismic Design of Buildings partial revision


Published on.

2013-12-19

Wenchuan earthquake showed that in strict accordance with existing norms for the design , construction and use of buildings in the face of local fortification intensity was higher than the earthquake

  Wenchuan earthquake showed that in strict accordance with existing norms for the design , construction and use of buildings in the face of local fortification intensity was higher than the earthquake , there was no collapse destroyed, effectively protect the lives and safety of the people. Description of the Tangshan earthquake in 1976 , the Ministry of Construction to start making house from 6 degrees higher than the seismic fortification intensity once and press the " earthquake " did not fall fortified targets seismic design decisions are correct.

  According to the Ministry of Construction to implement the State Council, "Wenchuan Earthquake Restoration and Reconstruction Ordinance " requirements , according to the Seismological Bureau of revision of earthquake disaster Amendment No. 1 single parameter , the corresponding changes to the fortification affected areas , and to amend certain provisions of the proposed increase , the total changes from 28 to 29 , which reads the following statistics :

  1 change fortification disaster involving Sichuan, Shaanxi, Gansu , a total of three .

  2 . Material performance standards by product modification, 2 , which has a mandatory provision .

  3 mandatory provisions 15 . The original provisions of the text adjustment 6 , mainly related to fortification classification and architectural design ; deleting about isolation, damping limit the scope of the provisions of an applicable ; additional structural elements involved in the basic requirements of prefabricated floor , mountain venue non- structural elements , stairways , special construction requirements 8 .

  4 Other modifications of 8 to 9 , involving slope , single-span frame , civil structural measures stone houses , and stairs involved in the overall calculation.

  The draft for approval , the underlined modify the content of the mandatory provisions in bold .

  3.1.1 All buildings should be the existing national standard " classification of seismic construction standards " GB 50223 to determine its seismic category.

  3.1.2 ( Delete )

  3.1.3 seismic standards for each class of building earthquake-proof , shall comply with the current national standard " classification of seismic construction standards " GB 50223 requirements.

  [ Revision Notes ]

  Divided into different categories and take a different seismic design requirements , is an important countermeasure to reduce earthquake hazards in the existing technical and economic conditions .

  This specification 2001 version 3.1.1 - 3.1.3 of the content has been defined by the classification standard GB50223, this revision can be directly referenced provisions are not repeated .

  3.3.1 Select the construction site , the project should be based on need , to acquire information on earthquake activity, engineering geology and seismic geology , seismic favorable , unfavorable and dangerous to make a comprehensive evaluation of the lot . Adverse lots should be made to avoid the requirement ; take effective measures will also be unable to avoid. The danger area, prohibited the construction of A and B buildings should not build a Class C building.

  [ Revision Notes ]

  This revision , the construction of housing construction in hazardous location requirements, made ​​a partial adjustment .

  3.3.5 venues and mountain building foundation design should meet the following requirements:

  A mountainous construction site should be based on geological, topographical conditions and requirements, in line with local conditions set slope engineering seismic requirements ; ferret high fill slope should be avoided , and the poor stability of the slope tall slope should be put back slope or sub- order grading .

  2 building foundation and soil, edge strongly weathered rock slope should allow sufficient distance , and its value should be based on determining the level of earthquake intensity , and take measures to prevent the destruction of foundation during an earthquake .

  [ Revision Notes ] :

  This section is added for mountain house siting and foundation design , a clear seismic requirements .

  3.4.1 The architectural design should be consistent with the concept of seismic design requirements , irregular construction program should be required to take measures to strengthen ; particularly irregular building programs should be specialized research and demonstration , to take special measures to strengthen ; should adopt serious irregularities the construction program .

  [ Revision Notes ] :

  This revision , the various irregularities building programs , were given treatment measures to improve building design and coordination of structural design .

  3.5.4 structural members shall comply with the following requirements:

  Masonry structures should be required to set up a reinforced concrete ring beams and structural columns , core columns , or the use of reinforced masonry and so on.

  2 concrete structure should be controlled cross-sectional dimensions and longitudinal reinforcement and stirrups settings to prevent shear failure prior to bending failure , prior to crushing of concrete reinforcement yielding , steel anchor damage in the first component .

  3 prestressed concrete members , shall be equipped with sufficient non- prestressed reinforcement .

  4 steel components should avoid local buckling instability or the entire component .

  Over five , concrete floor, high-level roof should give priority to in-situ concrete slab . When using prefabricated concrete floor , roof , floor system and the structure should take measures to ensure the integrity of the connection between the prefabricated panels .

  [ Revision Notes ]

  Precast concrete panels in this section against a strong earthquake off easily lead to damage of casualties , increasing the recommended cast floor , roof , with particular emphasis on prefabricated buildings, roofs need to strengthen the integrity of the basic requirements.

  3.6.6 seismic analysis of the structure using computer should meet the following requirements :

  Build a computational model , necessary to simplify the calculation and processing, should be consistent with the structure of the actual working conditions ; calculation should consider the impact of stair components.

  2 calculation software technical conditions should be consistent with the specifications and requirements of the relevant standards and special treatment should clarify its content and basis.

  3 complex structure of the internal forces and deformation analysis under multi- case earthquake , should adopt at least two different mechanical models and the results of its analysis and comparison .

  4 All computer calculations shall be confirmed by the analysis to determine reasonable and valid only for the engineering design .

  [ Revision Notes ]

  This revision , taking into account the stress state of the stairs with a ladder bracing panels , have a more significant impact on the overall stiffness of the structure . Proposed to be properly considered in the structure calculation.

  3.7.3 attached to the floor , the roof structure of non- structural components , as well as non- load-bearing walls in the stairwell , should take measures to collapse wounding or important equipment smashed a reliable connection with the main structure or anchoring , etc. to avoid earthquakes.

  [ Revision Notes ]

  Add this article evacuation stairwell wall channel seismic safety requirements, improve the protection of life .

  Enclosure walls and partitions 3.7.4 framework should be set up to consider the adverse effects on seismic , to avoid damage caused by unreasonable to set the main structure .

  [ Revision Notes ]

  Added to the mandatory provisions of this section , in order to strengthen retaining wall , partition nonstructural components , such as building seismic safety , enhance the protection of life .

  3.8.1 Isolation and energy dissipation design , you should use the function is mainly used in special requirements for the construction and seismic intensity 8,9 degrees buildings.

  [ Revision Notes ]

  In recent years , isolation and damping technology is relatively mature, and to non- mandatory provisions of this section .

  3.9.2 performance structural materials shall meet the following minimum requirements:

  A masonry structure material shall meet the following requirements :

  1 )

  Sintered common brick and brick firing intensity level should not be less than the MU10, which should not be less than the mortar strength class M5;

  2 )

  Small concrete hollow block the intensity level should not be less than MU7.5, its mortar strength rating not less than M7.5.

  2 concrete structure material shall meet the following requirements :

  1 )

  Strength grade concrete box beam , pillar boxes and seismic grade level frame beams , columns, joint core area, should not be less than C30; structural columns , core columns , ring beams and other types of components should be low at C20;

  2 )

  Seismic level is a secondary frame structure , its longitudinal reinforcement when using ordinary steel, the measured value and the measured value of the yield strength tensile steel ratio of not less than 1.25 ; yield strength steel standard values ​​measured value and strength the ratio should not exceed 1.3 ; and reinforced at maximum tensile elongation measured the total value should not be less than 9%.

  3 steel steel shall conform to the following requirements:

  1 )

  The ratio of yield strength and tensile strength measured value of the measured values ​​of the steel should not exceed 0.85 ;

  2 ) 3 )

  Steel should be obvious yield level , and the elongation of not less than 20% ;

  Steel should have good weldability and toughness qualified .

  [ Revision Notes ]

  This section will be replaced by sintering clay fired brick , some wider scope .

  The added elongation of reinforced , steel ductility is important to control the performance index . Its value based on product standards " steel reinforced concrete - Part 2 : Hot rolled ribbed steel " reinforced seismic performance indicators GB1499.2-2007 proposed regulations .

  Performance indicators of structural steel , steel products according to standards "Structural steel " performance indicators GB / T 19879-2005 requirements will numerator, denominator on the exchange, instead of yield strength and tensile strength ratio .

  3.9.3 performance structural materials , still should meet the following requirements:

  One should give priority to the ordinary steel ductility , toughness and weldability better reinforcement ; ordinary steel intensity level , longitudinal reinforcement should be selected in line with the seismic performance indicators of HRB400 hot rolled steel , may also meet the seismic performance of HRB335 grade Hot-rolled steel ; stirrups should be selected in line with the seismic performance of HRB335, HRB400 grade hot-rolled steel .

  Note:

  Test method shall comply with reinforcement of the current national standard GB50204 " concrete structure construction quality acceptance ."

  2 concrete strength concrete structures , not more than C60 9 degrees, not more than C70 8 degrees .

  3 steel Q235 grade steel should adopt the B, C, D and Q345 carbon structural steel grades B, C, D, E , low alloy high strength structural steel ; When there is reliable evidence , they can still use other kinds of steel and steel .

  [ Revision Notes ] :

  This revision , taking into account the product standard " steel reinforced concrete - Part 2 : Hot rolled ribbed steel " GB1499.2-2007 increased seismic reinforcement performance indicators ( intensity level number plus the letter E), provisions were made corresponding changes .

  3.9.4 When the need for a higher level of strength steel to replace the original design of the longitudinal reinforcement , reinforced carrying capacity should be designed according to the principle of equal value conversion, and shall meet the minimum ratio of reinforcement , crack checking requirements.

  [ Revision Notes ]

  Added to the mandatory provisions of this section , in order to strengthen the supervision and control of construction quality , to achieve the desired seismic targets. Text has been modified , the concrete structure requirements .

  3.9.6 reinforced concrete structural columns , core columns and bottom frame - Construction seismic shear wall brick wall of the room , the walls should be poured structural columns , core columns and frame beams .

  [ Revision Notes ]

  Added to the mandatory provisions of this section , in order to strengthen the supervision and control of construction quality , to achieve the desired seismic targets.

  4.1.8 When you need to strip when prominent spur , unfavorable location towering isolated hills, rocks , and strong non- weathered rock of steep slopes, river banks and slopes above the edge of the construction , such as Class C and Class C buildings, in addition to ensure their earthquake stability role , there should be lots of ground motion estimation adverse effects may produce amplification , the seismic influence coefficient should be multiplied by the maximum increase factor. The value should be based on the specific circumstances of the adverse determination of the lot , in the range of 1.1 to 1.6 using .

  [ Revision Notes ]

  Added to the mandatory provisions of this section , in order to strengthen the seismic capacity of mountain building .

  5.4.3 When calculating the only vertical seismic action , seismic bearing capacity adjustment factor shall be used for all types of structural elements 1.0 .

  [ Revision Notes ]

  This section is added as a mandatory provision.

  6.1.5 Frame structure and frame - shear wall structure, the frame and shear wall should be two-way set , columns and shear wall midline midline , midline between the beam and column centerline eccentricity greater than the column width of 1 /4, should be included eccentricity of. High-level framework should not be used single-span frame structure, multi- frame structure should not use single-span frame structure.

  [ Revision Notes ] :

  This section complements the control of a single inter- frame structure scope requirements.