The Surface + Design Event China 2021

     

2021.11.30-12.2 | Shanghai New International Expo Centre(SNIEC)

 

Analysis of different technical points of dry stone hanging and stone curtain wall construction

1. The current general recognition of stone curtain wall and dry hanging stone

In the actual construction process, regardless of the stone curtain wall or dry hanging stone, most of them appear in the form of subcontracting.

Because the construction technology of stone curtain wall and dry-hanging stone are similar, and the finished products are similar, it is unavoidable to understand that they are the same construction technology, the difference is only the difference between the requirements for height and seismic fortification intensity in the code; or: indoor It is dry hanging stone technology, and the outdoor is stone curtain wall technology. In fact, there is a fundamental difference between them.

2. The difference between stone curtain wall and dry hanging stone

2.1. Different applicable codes

The stone curtain wall is composed of metal members and stone panels. It is a building envelope structure suspended from the main structure but does not bear the load and role of the main structure.

The design and construction of stone curtain wall are mainly based on the “Technical Specifications for Metal and Stone Curtain Wall Engineering” and the “Building Decoration and Decoration Engineering Quality Acceptance Specifications” as the main basis for completion acceptance.

There are three main methods for the installation of decorative panels: traditional wet method (grouting method), dry hanging method, and direct bonding method. The requirements are mainly based on the requirements of the decorative panel (brick) project in the “Code for Quality Acceptance of Building Decoration Engineering” 2. Acceptance basis.

There are no special design specifications, and generally you can refer to other relevant professional specifications for design.

 2.2. Design requirements differ from depth

The design of building stone curtain wall should be designed by the design unit with the corresponding qualification for curtain wall design. At the same time, the design drawings and calculation books before construction must be approved by the relevant professional design of the original building design unit.

The design of the stone curtain wall mainly includes two parts: construction drawings and design calculation books.

Construction drawings: It shall include the necessary structure of the curtain wall and the design of various functions such as: design for preventing rainwater leakage and air penetration; fire prevention, lightning protection, and energy-saving design for curtain walls.

Under normal circumstances, stone curtain walls should not leak. The condensed water or water vapor generated by the ventilation layer between the stone and the main structure should be able to be discharged into the sewer centrally. The fire protection layer of the stone curtain wall should adopt isolation measures to form a fire protection zone at the floor, and use fireproof sealant to close the continuous heat-resistant steel plate fire protection zone.

The lightning protection device in the design of the stone curtain wall structure should be installed from top to bottom, and at the same time, it must be effectively and firmly connected with the lightning protection device of the main structure. The design and installation of lightning protection settings also need to be approved by the building design unit. The thermal insulation material of the stone curtain wall can be connected with the stone plate or directly attached to the structural body. In the structural design of the stone curtain wall, the bearing capacity, rigidity and displacement capacity of the curtain wall and its connecting parts should be designed.

Because the deformation capacity of stone curtain wall components is very small, the curtain wall components will have a certain side shift under the action of earthquake and wind. Therefore, the design of stone curtain wall should include the design of seismic structural measures. In order to prevent the displacement of the main structure from horizontal forces causing damage to the curtain wall components, it is necessary to design an elastic connecting member to avoid the influence of excessive lateral movement of the main structure.

The construction drawings of dry hanging stone are mainly the construction methods of stone installation. There is no design calculation book related to it.

Dry hanging stone is a kind of decoration integrated with the external wall. According to the requirements of the “Code for Quality Acceptance of Architectural Decoration Engineering”: the construction construction deepening design should be carried out by the construction unit with the corresponding decoration construction qualification based on the original architectural drawings.

There is no requirement for calculation of the structural system, materials and physical properties of dry hanging stone in the “Code for Quality Acceptance of Building Decoration Engineering”. The construction drawings can refer to the requirements of “Technical Specifications for Metal and Stone Curtain Wall Engineering” for structural and node design, but the design drawings are not supported by the design calculation book.

 2.3. Material requirements are different

The material, type, and mechanical properties of the embedded parts, skeleton, stone, and connecting parts of the stone curtain wall need to be calculated and determined in accordance with the “Technical Specifications for Metal and Stone Curtain Wall Engineering”.

Dry hanging stone has clear requirements on the material and model of the embedded parts, skeleton, stone and connecting parts, and has no requirements on mechanical properties. There is no relevant calculation as the basis.

 2.4. Different construction techniques

The stone curtain wall is connected with the main structure by embedded parts or chemical anchors, and the main structure requirements must reach C30. The stone curtain wall adopts a column support system, and a 1.5cm gap between the upper and lower columns is connected by a core column. The connecting metal corners of the curtain wall frame columns and other connecting pieces shall be bolted.

The beams and columns are also bolted, and most of the metal components of the curtain wall are bolted. Because the stone curtain wall needs extensive design and high requirements, the construction process is relatively complicated. The dry hanging stone is connected with the main structure by most of the rear embedded parts, the keel is welded to the embedded part, and the metal pendant hangs the stone on the keel to form a stone wall surface.

Dry hanging stone is a new technology in the current decoration. It avoids the common quality problems such as pan-alkali and hollow drum brought by the traditional wet operation process-grouting into the stone plate. Most of the keel and embedded parts are welded and connected, and the keel itself cannot withstand horizontal loads. The stone relies on the wall as a load-bearing body. The stone wall has no ability to recover after deformation and will deform. The dry hanging stone construction process is simple and the construction progress is relatively fast.

 2.5. different inspection items

When the stone curtain wall is used as the building envelope, it should provide the following: acceptance test report of the bending strength of the stone; test report of the freeze-thaw of the stone; test report of the pollution resistance of the sealant for the stone; On-site pull strength test report of embedded parts.

Dry hanging stone is used as a decorative form of the external wall. The testing that must be done only provides the on-site pull strength test of the embedded parts and the indoor granite radioactivity test report. The construction drawings can refer to the curtain wall requirements in the “Technical Specifications for Metal and Stone Curtain Wall Engineering” to propose corresponding inspection and test items. The code requires less material testing and testing.

 2.6. Construction acceptance data is different

The construction of the stone curtain wall is complicated, with many procedures, involving a wide range, the content of acceptance documents is numerous, and the organization and filing are complicated.

In addition to the tests of various materials and curtain wall inspections required by the specification, other acceptance information also includes: installation of rear embedded parts, connection nodes between columns and main structure, expansion joints of columns, connection nodes between beams and column structures, and curtain wall periphery Concealed acceptance of closing, lightning protection, fire prevention, etc.

Construction records of water immersion test, structural glue injection, ground resistance test, etc. Perception inspection records and corresponding inspection batch data.

Dry hanging stone has simple construction, fewer procedures, not extensive coverage, less construction acceptance data, and easy to organize and archive. In addition to the indoor granite radioactivity test report and the on-site pull strength test of the post-embedded parts, the code requires its covert acceptance data to include: post-embedded parts installation, keel installation, and corresponding inspection lot data.

Source: Stone Network