Effective Keyed Connections of Hollow-Core Floor Slabs With Walls in Modern Large-Panel House Building

Abstract

The paper considers large-panel constructive system of multi-storey buildings and its industrial basis creates conditions for intensive volume growth in house construction. Application of hollow-core panels are recommended as floor slabs that allows to increase a distance between bearing walls, to improve planning solutions, and also significantly to increase thermal and sound protection properties of floor discs (coatings). Keyed joints having the highest resistance to shearing forces are used to ensure joint action of the slabs with wall panels. A supporting unit of floor elements in the precast-monolithic constructive system ARKOS by means of concrete keys is considered as a prototype of the considered joint. In order to increase a bearing capacity and improve reliability of joints it is envisaged to reinforce keys with space frames. Improvement of joint units is possible to carry out with due account of total number of the factors influencing on strength. Poltava National Technical University named after Yuri Kondratyuk has developed a general methodology for assessment of bearing capacity in keyed joints which is based on the variational method in the theory of concrete plasticity and reflects specificity of stress-strain state of the failure zone. For experimental verification of this methodology investigations have been carried out with the purpose to test operation of keys when they are reinforced in mid-height and reinforcement is distributed in two tiers. The observed experimental fracture pattern in the specimens has confirmed kinematic schemes accepted for calculations and comparative analysis of experimental and theoretical values points to their closeness. Two-level reinforcement significantly improves plastic properties of concrete keys and excludes brittle failure. The proposed design of the joint unit for floor slabs with wall panels is characterized by the ratio of key dimensions and shape of reinforcing cages in the form of hollow cylinders which ensure higher strength and seismic resistance of a joint.

Stress-strain state panel buildings and welded butt joints

“…There are a large number of scientific publications on the nonlinear deformation of load-bearing elements of panel buildings in construction practice, but information on experimental data is limited. Various studies are devoted to the analysis of the work of shear bonds [10][11][12], welded embedded parts, vertical joints, horizontal joints and plate ties [13][14].…”

Improved Joints of Reinforced Concrete Elements in Precast-and-Cast-in-Place Construction Based on Destruction Mechanics

“…The authors [9] proposed a contact-platform keyed joint of panel walls with zones of support of multi-hollow slabs with round voids, which are brought beyond their boundaries (Fig. 4).…”

“…5). In the authors' experimental researches [9], the effect of f cd and f ctd values was studied, as well as reinforcement (compression) on the keys strength which are destroyed by shearing. Heavy and ceramsite concrete with prism strength f c, prizm =10-56.9 MPa was used.…”

Experimental Study on the Multikeyed Joints of Concrete and Reinforced Concrete Elements

“…At PoltNTU during 1985 -2017 years, system studies of keyed joints of concrete and reinforced concrete elements were carried out [18,19]. Seven series of the experimental samples have been made and tested.…”