Paper Keywords: CL building system environmental protection and energy-saving design and construction
Abstract: This paper introduces the construction technology and advantages of CL structural system with examples.
1 project overview
The total area of a residential area is about100000, of which more than100000 is a CL structure system. This structural system integrates new structures, new materials, new processes and new technologies, and it is a residential pilot project to promote energy-saving and environment-friendly buildings in Hebei Province.
Design and application scope of 2 CL structure system
(1) system design: CL (composite lightweight) system is a new structural system. CL structure is a spatial structure composed of CL wallboard, solid silicon wall, assembled integral floor or cast-in-place floor and post-cast edge members, and its mechanical properties belong to shear wall structure. CL wallboard is the main stress component of CL wall. It is composed of two cold-drawn smooth low-carbon steel wire welded CL mesh pieces and three-dimensional inclined web steel wire (galvanized low-carbon steel wire) welded to form a space skeleton, with polystyrene board sandwiched in the middle to form a CL mesh frame panel, and concrete poured on the inner and outer sides to form CL wallboard. CL wall 180 mm, middle CL core-polystyrene board 50 mm, density, inner concrete thickness 90 mm, outer concrete thickness 40 mm, inner and outer steel mesh spacing 50 mm, outer cold-drawn low-carbon steel mesh 4 mm, inner cold-drawn low-carbon steel mesh 3 mm, and web 3mm galvanized low-carbon steel wire.
CL core board adopts grade II molded polystyrene foam plastic board for thermal insulation, and its performance indexes are as follows: the apparent density range is; Oxygen index of flame retardant (zR type)? 30%, the rest should comply with the provisions of GB 1080 1.
The mechanical properties of CL grid plate shall meet the following requirements:
The tensile test results of solder joints of CL mesh shall be no less than
The average shear strength of each group of shear specimens shall conform to the shear strength calculated by formula (1):
A- the cross-sectional area of steel wire. If welding steel wire with different diameters, the cross-sectional area of steel wire with larger diameter is mm;
1. The specified yield strength of this grade of steel wire.
(2) Scope of application: This structural system is suitable for residential buildings or public buildings with more vertical and horizontal walls and seismic fortification intensity of 8 degrees or below, and can meet the needs of small high-rise houses, affordable houses and 6-story villas with 12 floors or below. The total building height should not be greater than 36m, and if it is an 8-degree IV venue, the building height should not be greater than 27m and the building height should not be greater than 3 m.
3 CL wall structure
CL wall in this project adopts two construction methods, that is, both sides are prefabricated and both sides are cast in place.
3. 1 construction preparation
(1) Be familiar with design drawings, technical specifications of CL structural system and construction quality acceptance specifications of CL structural engineering.
(2) (2) After the CL grating plate comes into play, it shall be sampled immediately for mechanical performance inspection according to the regulations, and its quality must conform to the provisions of relevant standards.
(3) Make the prefabricated brick tire mold of CL wallboard with smooth surface.
(4) Determination of self-compacting concrete mixture ratio.
(5) Technical disclosure for each type of work.
3.2 Construction process flow
CL grid plate order making, approach CL grid plate alkali pad making and maintenance. Chiseling the root of silicon shear wall, cleaning up sundries, centralizing embedded steel bars-solid shear wall, edge members of CL wall, binding structural column steel bars -CL precast slab (CL grid plate), hoisting and positioning, binding node connection anchor bars-welding template support bars, embedding pipe boxes by electricians, installing wall formwork 1, pouring self-compacting alkali, and demoulding and maintenance.
3.3 Construction Technology
3.3. 1 CL grating plate order making and entry
It is very important to make orders for CL grating plates, draw sketches, determine specifications, mark detailed dimensions and quantities, and indicate the project location, project name and entry date. Special attention should be paid to the specifications and models of the grid plate at the rest platform of the stairwell and the wall connected with the inclined roof. Full-time CL wallboard construction technicians should be set up for this work.
3.3.2 Manufacture and maintenance of CL grid silicon pad
According to the progress of the project, after CL grid plate comes into play, use PVC plastic pipe mould (cut into four equal gaps and insert mesh) to make alkali pad on it. The strength grade of silicon pad is the same as that of shear wall, and the distance from the edge of CL polystyrene plate is 100- 15mm, and the middle spacing should be appropriate. 600 mm, the cushion blocks are arranged in a plum blossom shape, and the silicon cushion blocks on both sides should be symmetrical and placed in the same position, so as to avoid the lateral pressure generated during asymmetric silicon casting from shifting and crushing the CL core plate.
CL wall prefabrication
Double-sided prefabrication refers to pouring fine stone concrete on both sides of the core plate, fixing the hoisting embedded parts and additional reinforcement at the wall edge and hole in the grid plate, preparing the formwork at the wall edge and hole, checking that there is no slurry leakage at the reserved hole position, and checking the support mode of the grid plate and the firmness of the formwork support.
3.3.4 Reinforcement binding
In this process, the binding of the reinforcement of the silicon-fixed shear wall should be put before the installation of the CL grating plate, mainly considering that after the installation of the CL grating plate, the reinforcement of the silicon-fixed shear wall is not easy to bind due to the anchorage length and other reasons, and the CL polystyrene plate is easy to be damaged. After the installation of CL grid plate is completed, tie the constructional column reinforcement, the reinforcement at the edge of CL wall and the additional reinforcement at the corner of doors and windows (to prevent oblique cracks at the corner).
3.3.5 Hoisting and temporary fixing of CL grid plate and precast slab
(1) When lifting the CL grating, please properly protect the CL grating. Don't hang the tower crane hook directly on the grid plate, which will easily lead to the disconnection between the grid plate and the web steel wire and the overall bending of the plate. CL grating plate can be hoisted on the flat plate, and the quality acceptance requires the solder joint to be disconnected. 10%, and can't have 5 or more solder joints in succession, and bend the whole cluster? Attention should be paid to protecting the silicon pad during the hoisting of 3 mm CL grid plate.
(2) Hoisting the CL precast slab. Because CL precast slabs are relatively heavy, and some of them weigh more than 3t, safety technical disclosure should be made before hoisting. Before hoisting, pre-hoist to see if the hoisting embedded parts can meet the load-bearing requirements. When hoisting, balance should be maintained. It is not allowed to lift at a single point, but at two points at the same time. When hoisting, the wall should be dragged until it is erected to prevent the anchor cable from being damaged. Before hoisting, the wall should be inclined.
3.3.6 CL wall formwork installation
The welding formwork brace can be reinforced and welded on the anchor bar at the bottom of CL grid plate according to the ground trip line. The deviation should be controlled within 2 mm to ensure the correct section size and position of the panel wall. The length of reinforcement shall be cut in advance according to the wall thickness. If the interior wall is not plastered, both ends should be painted with antirust paint to prevent the rebar from polluting the wall due to wet corrosion.
3.3.7 Mixing, transportation and pouring of self-compacting concrete
Because the CL wall is thin on both sides, with inclined web steel wires inserted in the middle, self-compacting high-performance vibration-free concrete is adopted according to the engineering characteristics, which has the characteristics of high fluidity, high cohesion, segregation resistance and high filling.
According to the needs of the project, the properties of self-compacting concrete mixed on site meet the following requirements: slump? 255 mm; Collapse spread? 600mm gas content < 2.0%; The setting time is normal; Strength grade C25/30. When pouring, silicon should be poured on both sides of CL insulation board at the same time to prevent the insulation board from running off.