Abstract.When designing large-panel buildings, it is necessary to take into account the work of wall panel joints. In addition to welded joints, monolithic joints in the form of pinned joints of the loop releases of adjacent wall panels are widely used. The main characteristics of a joint in the design scheme are its rigidity and bearing capacity under the action of shear and tensile (compressive) forces. This paper studies a new type of an inter-panel joint in the form of a fastener junction of wall panels made using a bracket of reinforcing steel and a metal plate joining the ends of the bracket. Due to the creation of a closed loop of voltages in the node, its high load-bearing capacity is assumed as well as the possibility of using this connection under dynamic effects on the building. An experimental study of the strength and rigidity of the joint at tensile loading along the joint axis was carried out, the breakdown of the joint, the stiffness characteristics and the bearing capacity of the samples were determined. The numerical modeling of the joint's work on stretching to the formation of cracks is carried out.

No abstract

Recently, the world has seen a tendency of reinforced concrete housing construction industrialization. Russia has gained extensive experience in large-panel housing construction, which helps to find optimal structural solutions, but new solutions lead to the need for additional study. Modern software systems allow you to build volumetric models of a building, taking into account physical non-linearity, which helps to take into account the actual distribution of efforts between the elements. At the same time, to build the correct model of a large-panel building, the flexibility of joints between them is required. The flexibility is calculated by online tests the results of which are used to build the future model of a building in the process of its designing. The calculation model of a building gives an approximate estimate of structural behavior and the degree of its accuracy depends on the correct selection of the initial premises. This article estimates the numerical model of a large-panel building by comparing it with the results of direct observations of shear movements in the vertical joints of the most loaded walls of a building under construction. The observations were carried out on a 26-story large-panel building with a cross structural system with self-supporting external longitudinal walls. Vertical joints are monolithic reinforced concrete with the use of dowels with cable loop transverse reinforcement.In addition, estimation of forces at the joints is also given. In general, we may conclude that the calculation model of a large-panel building is applied correctly using elastic-flexible connections with limiting ultimate forces for vertical joints modeling.The modeling part of the study is performed using a finite element model taking into account the magnitude of the joints flexibility and the actual stiffness of the building structural elements.The results of the study can be used in modeling, calculation and design of large-panel buildings, and they provide new scientific knowledge about the operation of buildings of this type.

No abstract

The need to cut construction cost of residential and public buildings and provide them with a free and transformable planning structure during their operation cause interest in building wall systems with a large step of bearing walls. In order to reduce labor inputs and increase rate of construction in such building load-bearing system it is also necessary to maximize the use of large-sized prefabricated products and minimize consumption of in-situ concrete. In this case prefabricated products should be substituted according to the conditions of local (regional) construction industry base and volume of in-situ concrete must be sufficient to ensure a complete redistribution of internal forces between elements of the bearing system under load. As for the described bearing wall system of a multi-storey building the paper presents a flat precast solid floor formed by hollow-core slabs and monolithic crossbars supported by load-bearing walls. The hollow-core slabs supported at the ends on cast-in-place crossbars in the planes of bearing walls are arranged in dense groups between cast-in-place braced cross-beams. Dense contacts between overlapping elements are fixed by internal bonds. New data on distribution of forces in floor elements under the action of a vertical load have been obtained on the basis of full-scale tests and existing theoretical assumptions. It has been established that due to this load reactive thrust forces ensuring an operation of every hollow-core slab group in the floor as an effective solid plate supported along the contour have been originated in the floor plane along two main axes. Calculation of the reactive thrust forces makes it possible more accurately to assess a load-bearing capacity and rigidity of the precast solid floor and to increase a step of bearing walls up to 8 m and more while having hollow-core slabs with a thickness of 220 mm.