Research on Mechanical Properties of Concrete Block Masonry and Seismic Behavior of Reinforced Masonry Multiwythe Wall
|Keywords||Grouted masonry Reinforced masonry Seismic performance Multiwythe wall Low cyclic experiment Compressive strength Shear strength Thermal insulation|
Compared with the developed countries, energy consumption in China was considerable.The building energy consumption in China increased year by year and the proportion in the total energy consumption was growing.In this regard, The Ministry of Construction established the principle of "Design Standard for Energy Efficiency of Residential Building in Hot Summer and Cold Winter Zone".However, the experimental research on seismic behavior of the energy saving wall used in tall building in Hot Summer and Cold Winter Zone has not been carried out yet.Therefore, the experimental research on seismic behavior of reinforced masonry multiwythe wall was significant.Compared to ordinary grouted masonry, the mechanical properties of the grouted slotted block masonry were more realistic.In this paper,9 compressive specimens of 3 groups were tested to investigate the cracking resistant load,ultimate load,failure modes and deformation capacity of the grouted slotted block masonry. The results showed that the grouted slotted block masonry cracked early and the compressive strength was moderately identical with the ordinary grouted masonry. Based on compressive mechanism of concrete block masonry and the main factors influencing the compressive strength,the calculation formula of compressive strength was established by the stress method.The unified compressive strength formula of grouted masonry and ungrouted masonry was established also.By compressive tests on specimens,the whole stress-strain curve was obtained and the value of elastic modulus of the grouted slotted block masonry was proposed.Through the experiments of 18 shear specimens of 3 groups,the cracking resistant load,the ultimate capacity and deformation capacity of the grouted slotted block masonry were analyzed.Through the experiments of 24 shear specimens of 4 groups,the cracking resistant load,the ultimate capacity and deformation capacity of the N-block masonry were analyzed.It was shown that the shear strength of the two kinds of grouted masonry was moderately higher than ordinary grouted masonry. Based on shear mechanism of concrete block masonry and the main factors influencing the shear strength,the calculation formula of shear strength was established by the Hoffman theory and modifying the calculation formula in the Code for Design of Masonry Structures. Through the compressive experiments of 2 whole-tied-type reinforced masonry multiwythe walls,the overall compressive performance of the walls were analyzed. The failure modes,the ultimate strength,deformation capacity, hysteretic behavior, stiffness degradation,ductility and dissipative characteristics etc seismic performance of interior and exterior wall of reinforced masonry multiwythe walls had been preliminary studied through 2 walls.The consequents could provide theoretical basis for designing high-level multiwythe walls.The heat transfer coefficient and index of thermal inertia of multiwythe walls were analyzed in which different heat preservation stuff was filled.And through the thermal performance test,the heat transfer coefficient of 2 walls was detected.It was shown that the thermal performance index of multiwythe walls filled with polystyrene board met standard requirements.The results of the paper can be used to reference for design and theoretical research of reinforced masonry multiwythe walls.