Study On Composite Shear Wall Structure System With Permanent Thermal-Insulation Wall Form Of Glazed Hollow Beads

The composite shear wall system with permanent thermal-insulation wall form of glazed hollow bead is a new kind of energy-saving building, which was proposed for the request of carrying out the building energy conservation, developing the green building materials and promoting the wall material renovation in the residential building in China. Its original intention was to completely replace the masonry-concrete structure so as to achieve the domestic energy-saving and land-saving.The composite shear wall uses the thermal-preservation blocks of glazed hollow bead as the wall forms which are built in hole-to-hole and stagger-joint to form the mould of cast-in-place concrete wall, and then form a chamber in the mould. There is configured with horizontal and vertical reinforcement mesh in the wall form. The self-compacted concrete is filled along the upper chamber of wall form so that the wall form and concrete will become a composite shear wall, which is used as the loading-bearing and lateral-force resistance structure. There are ring beams along the upper part of internal and external walls, and the floor and roof are built with cast-in-place or integral-assembled structure. Therefore the wall thermal-preservation and structure are simultaneously constructed to form a integral system.As a kind of self-thermal-preservation system, the composite shear wall system is developed after summarizing the successful experience of many overseas systems, such as the system of thermal-preservation mould, the load-bearing wall with stay-in-place mould, and the load-bearing wall system with small concrete hollow block. It is also complied with relevant standards and specifications for buildings in China. The system is realized to combine the structure and thermal-insulation technology, and the construction of wall thermal-preservation can be finished in the course of the construction of structure. The performance of wall thermal-preservation is excellent and is much higher than the requirement of energy conservation design standard. The structure is the slitted shear wall, which has the excellent deformation capacity, and can realize the seismic structural control. The system has also brought significant economic benefits when it improves the housing qualities of residential buildings, such as application, security, durability, comfortableness. The system is applied to the multi-story and mid-highrise residential buildings or the public buildings with more vertical and horizontal walls. It can be used for seismic and non-seismic areas and can meet the needs of thermal-insulation in different climatic zones. Additionally it complies with the needs of sustainable development, including land-saving, energy-saving, water-saving and materials-saving. It has provided a new path for the green and health residential buildings.A more deeply research on this system was provided. The study consists of three aspects including technical feasibility studies, mechanical properties studies and economical analysis. The contents of technical feasibility studies include materials development and wall form design; the contents of mechanical properties studies include the research on seismic performance of the composite shear walls and the seismic dynamic analysis on the test building model of this system; the economic evaluation includes the evaluation model's establishment and the examples of evaluation. The details of research are mainly the followings:1. The features and performance requirements of wall forms were determined according to the requirements of relevant specifications and regulations and the applied conditions of the project. On this basis, suitable raw materials were chosen to develop the energy-saving and environment-protection type of the inorganic thermal-preservation materials appropriate to wall forms. And then design was carried out for the wall forms according to the results of numerical simulation and thermal calculation. Both the calculation and the construction practice of test building showed: the thermal-preservation structure could meet the requirement of the highest energy conservation design standards of China, saving 65% of energy. Besides, the thermal-preservation wall form had strong bending strength and anti-deformation capacity, it could meet the requirements of the strength and stiffness of mould in the code for acceptance of constructional quality of concrete structures.2. The experiment and numerical analysis were proposed in the paper. Experimental work and finite element analysis on composite shear walls under vertical loading were carried out, the bearing capacity and failure mode were analyzed. The results showed that the bearing capacity of composite shear wall specimen was close to that of common shear wall, and that delay-destroy occurred on the specimen. It was consistent with the designed destroy pattern that the destroyed place was around the rib of wall form. During the period of test, the specimen's out plane stability was good. The stay-in-place wall form and the slitted shear wall had a good performance to cooperate.3. On the basis of the test study, the finite-element analysis program ANSYS was used to give a non-linear analysis on the slitted shear wall. The seismic behavior of the slitted shear wall was studied as compared with the common shear wall. Comparative analysis was carried out on the characteristics of the slitted shear wall, including the destroy patterns, stress-strain, rigidity and ductility. The analysis results showed that the slitted shear wall had enough strength and rigidity, and could meet the first-grade standard requirement of seismic fortification. The bearing capacity could be calculated referring to the present formula of shear walls in the elastic period. The preset vertical slits showed a great influence on the integral performance of the wall after cracking. The slits could affect the break mode, and moderate structural stiffness and earthquake reaction, simultaneously those had improved the ductility of the structure and increased its energy-dissipation capacity. The rigidity degradation the components had never mutated, with stable performance, which is favorable for the components' structure in case of more earthquakes to meet the requirements of seismic fortification, including small rigidity, high damping, good ductility and good energy-dissipation capacity. And then according to the principle of orthogonal test, studies on the influence of many factors, such as axial compression ratio, shear span ratio, wall thickness, reinforcement ratio and combined columns, were also carried out on the seismic performances of slitted walls.4. Based on the three-dimensional finite element model in accordance with the actual work, the seismic dynamic analysis on the slitted shear wall structured building was conducted by using ANSYS software. The analysis results showed that this structure had slighter self-weight, smaller deformation and better seismic performance. The deformation of slitted shear wall structure was basically the same as that of common shear wall structure, and their layer shearing force and layer displacement was very similar. So in course of integral structural design, the structure of slitted shear wall could be simplified to common shear wall structure. The greater stress occurred around the clapboard of the wall forms, i.e. there was the weaker position around the slits of the shear wall system, where the distribution was dispersed, which met the ideas proposed in the period of wall form design, "limit the damage form under the seismic load".5. Based on the theories of systematic engineering, value engineering, life cycle costing and hierarchy analysis process, the system of the evaluation index of residential performance was established, and the quantitative evaluation methods of performance were determined. Additionally, a life cycle cost model of energy-saving buildings was established. Finally, an evaluation model based on value engineering is set up. With the evaluation model, a comprehensive economical analysis for this construction system was given. The result of the economical analysis showed that the capability price ratio (value) of this system was significantly higher than that of the common shear wall system and the masonry-concrete structure. So its economic efficiency was the best.The research of this project may contribute to Shanxi Province and similar areas to develop the new structure system and the new building materials, so as to conserve energy and protect arable lands. This project has gained the support of the National Natural Science Fund (item number: 50778118) and the support of Shanxi Natural Science Fund (item number: 2006011050).