Material selection and structural design standards for stone curtain walls
1)Stone sealing should be designed according to the outer protective structure, and igneous rock should be used for stone curtain wall slabs.
2) Natural stone curtain walls should not be used in high-rise and super high-rise buildings. When the design requirements are adopted, there should be measures to prevent stone chipping.
3) The frame of the stone curtain wall should be designed with comprehensive consideration of the building facade effect, civil structure form, installation form of the stone curtain wall, etc., not only to ensure the safety and reliability of the curtain wall system, but also to consider the feasibility of the construction process.
4) the stone curtain wall and its connectors should have sufficient bearing capacity, rigidity and displacement relative to the main structure. The uprights of the curtain wall framework should be connected to the main structure through metal corners, and bolts should be used between the uprights and the corners, and the bolt backing plate should have anti-loosening and anti-skid measures.
5) Non-seismic design stone curtain wall, the stone shall not be damaged under the action of wind; seismic design stone curtain wall, the curtain wall can still be used after the fortification intensity earthquake; the curtain wall frame shall not fall off under the action of rare earthquake.
6) In the design of stone curtain wall components, full consideration should be given to the safety of the curtain wall system under the influence of gravity load, wind load, earthquake, temperature and displacement of the main structure.
7) the internal force and displacement of the curtain wall components can be calculated according to the elastic method, and should meet the following requirements:
1. Stress or bearing capacity
2, displacement or deflection
In the formula, σ——the design value of the larger stress of the section caused by load or action;
F——design value of material strength;
S——The design value of the internal force of the larger cross section caused by load or action;
R——design value of member's section bearing capacity;
U——the greater displacement or deflection caused by the load or the standard value of the action;
［U］——The allowable value of displacement or deflection.
8) When designing the ultimate state of the bearing capacity of stone curtain wall members, the combination of its function shall meet the following requirements:
1. When there is no seismic action effect combination, it should be carried out as follows:
2. When there is a combination of seismic effect, the following formula should be used
In the formula, S——the design value of the combination of action effects;
SGK—— standard value of load effect;
SWK——standard value of wind load effect;
SEK——the standard value of seismic action effect;
ST——The standard value of temperature effect;
ST——The standard value of temperature effect;
ΓG—— partial load factor;
ΓW——partial coefficient of wind load;
ΓT—— partial coefficient of temperature effect;
ΓE——partial coefficient of earthquake action;
ΨW——the combined value coefficient of wind load;
ΨE——the combined value coefficient of earthquake action;
ΨT——Combined value coefficient of temperature effect.
9) The partial coefficients of load and action effect combination shall be adopted according to the following regulations:
1. When calculating the bearing capacity of building curtain wall components, connectors and anchors:
The partial coefficient of gravity load γG: 1.2;
Wind load partial factor γW: 1.4;
Seismic action sub-factor γE: 1.3;
The temperature effect partial coefficient γT: 1.2.
2. When the load effect plays the main control role, its partial coefficient γG should be 1.35, and the variable effect participating in the combination should be limited to the vertical load effect.
3. When the load effect is beneficial to the member, its partial coefficient γG should not be greater than 1.0.
4. When calculating the displacement and deflection, the wind load factor γW and the load partial factor γG should both be 1.0, and the combination of action effects may not be considered.
5. The combination coefficient of variable action shall be adopted according to the following regulations:
(1) Under normal circumstances, the combined value coefficient of wind load ψW should be taken as 1.0, and the combined value coefficient of earthquake action ψE should be taken as 0.5.
(2) For suspended ceiling stone or suspended floor stone and its skeleton, the combination of seismic effects should be considered, and the combined value coefficient of wind load ψW should be 1.0 (when the effect of the load does not have the main control effect) or 0.6 (the effect of the load The main control function).
(3) Each effect combination of the stone curtain wall load should be implemented in accordance with the current "Building Design Load Code" (GB-50009), and the design should be carried out according to the most unfavorable combination principle according to the specific project.