Choosing dry hanging method.
There are several methods of stone dry hanging steel pin-type form, through the slot, the short slot back bolt, etc., more commonly used two kinds of short slotted bolt and back, hung way comparison, short trough low cost but is less secure than back bolt, generally used in stone weight is not too big or not too high when the safety factor; solid back bolt dry hanging stable, but higher costs for large block of stone (thickness 30 when the stone mm larger than 1.5?O) or on the stone when higher safety performance.
Stone Selection.
For the deepening of the design, it should be compatible with the design and construction side of the unit work, depending on the design side of the curtain material color ruled form and architectural renderings and other requirements of the construction side to provide all kinds of stone samples as soon as possible to assist them in determining the use of stone. Usually in several stone selection should be based on possession of the stone materials, the surface characteristics of the proposed key consideration with stone, color and texture and other technical performance indicators. Although stone supplier has been given the physical properties of the stone, but the stone as a natural material whose physical properties vary greatly, it is necessary to re-confirm, in order to establish the appropriate design specifications for the stone design.
Construction design.
Hanging stone construction design basis for: floor plans, elevations, node large drawing, drawings and other relevant requirements and hanging stone of calculations required with other professional hanging stone fit. Construction design architect must do both to meet the requirements, but also with the actual situation of the site coincides construction design elevation design includes the installation of stone, stone nodes large drawing design, detail design, and other stone processing .
1, the installation elevation design: building installation established in accordance with the requirements of sub-grid elevations of the plate, in the facade of different shapes or different sizes of stone are individually numbered, numbered and should ensure that the only convenient and practical, designed stone FIG surface should be cleaned each facade express all the different kinds of stone plates. If the project is more complex shape, it is easy to find paper hanging stone elevation, but also design hanging stone elevation installation location index chart, clearly showing the building of the wall in each region corresponding siding facades number Figure number.
2, Stone node large drawing design: the corner of the building, windows, roof shape, stone and other complex parts, size and connections, should be a separate node design hanging stone large drawing to show these parts of the actual stone Happening.
3, stone processing detailing: After installation of stone elevations and node large drawing by the architect approved by stone to stone installation details and dimensions ruled node large drawing of elevation on the processing Detailing the detail of the stone processing known as single. In determining the specific shape and hanging stone processing size shall cross-check to be sure (especially when using the more expensive imported stone) so as not to cause huge economic losses.
Field force performance test.
Hanging stone models and theoretical calculations, after all, often the scene of actual stress situation is different, in order to verify the accuracy of the calculation results of the theory, must be adopted by a fixed system of fixed hanging stone stone at the construction site, then it gradually applied load and design requirements observed and recorded its overall force performance. Finally, according to test results of mechanical analysis and research to ensure that the hanging stone in actual use does have a considerable degree of safety.
Stone physical performance test.
Stone for a project to establish a test design specifications, it must be able to take representative samples with a stone, or the selection of the sample directly from the stone to be used in the building. The physical properties of hanging stone mainly include flexural strength, modulus of rupture, compressive strength, water absorption and bulk density, these indicators can be obtained by standard test methods and corresponding standards have specified minimum physical performance.
Hanging stone force transfer system
Sheet maximum stress can be simplified calculation method or program element is calculated. It is worth emphasizing that some special stone texture because of its unique characteristics leaving the stone has a very clear difference in plant high strength and direction of the plate length board shall each of these two different directions calculated intensity. In addition, while computing the stone reaches a certain point the direction of maximum stress, the stress must be calculated in the vertical direction.
1. Stone allowable stress
According to the aforementioned physical properties of the stone, the stone can be obtained corresponding strength index. Usually hanging stone for a building of granite, marble and limestone, according to various stone unique performance characteristics and construction experience in stone above the safety factor is the use of mechanical calculations should be different. American industry association for all kinds of stone stone are given the appropriate safety factor recommended. As for limestone, limestone design safety factor of US industry recommended value is 8. The experimental out of stone bending strength and strength design safety factor divided by the corresponding compression, you can often get the allowable stress.
2. stone plate bending own checking
For anisotropic stone, stone plate bending posture checking into two cases. First occurrence stone plate in the maximum bending stress point in the other direction of the stress is zero, as long as the stone is less than the maximum stress allowable stress corresponding direction on the stone plate bending their performance to meet the requirements, otherwise not be met. The second is the occurrence of the stone plate in the maximum bending stress point in the other direction is not zero stress, it should also be taking into account when checking the stress. Then you can apply the theory of internal friction, set a direction for the X, another vertical direction is Y, the following equation is satisfied, then the stone plate bending their performance to meet the requirements, otherwise not be met.
3. Shear pin hole stone Checking
First calculate the depth of the stone plate thickness and other geometric parameters of the pin hole at the converse is not to satisfy the geometric parameters of depth, the thickness of the stone plate pin holes and the like.
Stone dry hanging system mechanics and computing
First, determine the effect of load and walls suffered form, and then determine the stone dry hanging manner, and to determine the model of stone plates, security forces carried out calculations to finalize construction system according to the form of dry hanging dry hanging system suffered load value and used accessories, connectors, horizontal, vertical keel buried and size specifications. Stone dry hanging system design and should meet the requirements of national industry standards JGJ133-2001 "metal and stone curtain wall engineering and technical norms."
1. Loads.
Generally considered when calculating weight, wind loads and seismic loads suffered material and its mode of action in accordance with the load combination. The corresponding partial coefficients and combination coefficients should be strictly in accordance with regulatory requirements for access, for some special buildings, design specification for the corresponding load calculation values have special requirements, the calculation should control and regulate the maximum value whichever . When dry hanging system for the calculation should be based on the characteristics of the rigid force transmission determine its load suffered mechanics calculations. sometimes. When some of the load is not easy to determine, the size can be determined by simulation test.
2. Stone computing.
Stone calculation including siding and computing sector itself flexural and shear plate hanging pendant pin junction calculations. Sometimes the stone should calculate thermal stress cracking. Calculated with stone dry hanging the way, this paper takes a back bolt dry hanging stone fixing system will be described. Stone plate suffered loads including wind and seismic loads of horizontal, vertical seismic load and the weight of the stone. And thermal stress cracking temperature changes. Back bolt dry hanging stone typical installation system through up and down the 2 groups (4 groups) pendant will be fixed stone, from which the top two stone pendant bearing the weight of the stone and the binding effect of stone in the direction perpendicular to the plane of the stone, just below the two groups pendant from the constraints of stone in a direction perpendicular to the plane of the stone. When stone bending calculation shall calculate the four-point support plate stress. Calculating edge length a0, b0 resulting maximum bending stress should not exceed the design value of the bending strength of stone plate design value; when the shear stress on the bolt back in the stone pendant plate shear generated by the calculation, according to the corresponding general empirical formula calculate required suffered slate shear stress criterion is not greater than the design value of the shear strength of the sheet. It should be noted that the vertical shear stress only on row two pendant bear, not shared by all four groups pendant.
Design of dry hanging system.
In the stone walls engineering, design stone hanging system is generally complete independence by the construction unit, since the walls as a suspension system characteristics, the system determines the design of dry hanging curtain wall structural safety, has a special importance, but because it belongs hidden project, in particular, should be given adequate attention.