Theoretical and experimental analysis of load-carrying capacity of steel-concrete composite beams with glass-fibre-concrete slab
The paper deals with the problems of the theoretical and experimental investigation of load-carrying capacity of steel-concrete composite beams with glass-fibre-concrete (GFC) slab. The paper presents some selected results of the more extensive research realized on the authors workplace and oriented to the utilization of high-strength steels and high-performance concretes in steel-concrete composite structural members. This paper is directed towards one part of this research only, which represents theoretical analysis of the bending moment capacity and experimental verification of the actual bending moment capacity of steel-concrete composite beams with glass-fibre-concrete (GFC) slab in connection with their actual behaviour and corresponding relevant failure mechanism. Within the framework of the bending moment capacity analysis four basic types of beams have been (or will be, respectively) investigated, all of them composed of 3 different steel IPE cross-sections (IPE180, IPE200, IPE220) and concrete slab: (i) beams with GFC slab without usual steel reinforcement subjected to sagging bending moment, to investigate the contribution of GFC only to the sagging moment capacity; (ii) beams with GFC slab with steel reinforcement (reduced amount) subjected to sagging bending moment, to investigate the contribution of GFC slab and steel reinforcement together to the sagging moment capacity and to compare it with the first case; (iii) beams with plain concrete (PC) slab subjected to the sagging bending moment, to compare the results with the first case only; (iv) beams with GFC slab without steel reinforcement subjected to hogging bending moment, to verify the contribution of GFC to the hogging moment capacity. During the experimental parts of this research in common 27 loading tests of steel-concrete composite beams have been realized so far (but no all results are evaluated in detail so far) and other 9 specimens will be tested immediately. The attention was paid mainly to the following significant problems: the efficiency of the utilization of fibre-concrete slab in steel-concrete composite beams subjected to sagging or hogging bending moments, too; the effectiveness of the contribution of glass-fibre-concrete to the moment capacity of steel-concrete composite beams in comparison with reinforced concrete and plain concrete. Key-Words: Composite member, steel-concrete beam, glass-fibre-concrete, load-carrying capacity, resistance, sagging bending moment, experimental verification, theoretical analysis.
DESIGN OF EXPANSION ANCHORS TO CONCRETE BASED ON RESULTS OF EXPERIMENTAL VERIFICATION
ABSTRACT: This paper deals with the problems of the fastening of steel structures to concrete constructions using the post-installed anchoring elements. The paper is oriented to the presentation of some results of the analysis concentrated to the actual behaviour of the particular type of steel mechanical anchors, so called expansion anchors, during the loading process. Within the frame of the experimental verification, using the realized tests results and their elaboration, the load-carrying capacities for the corresponding failure mechanisms were obtained. Within the frame of the theoretical analysis, using the tests results statistic evaluation, the probabilistic models were created, for the subsequent reliability analysis leading to the derivation of the characteristic and design resistances. The problems mentioned above were solved for some selected failure mechanisms and load-carrying capacities of expansion anchors under tensile force namely, for static loading actions and eventually for dynamic loading actions.
Evaluation of buckling load and dynamic performance of steel shear wall retrofitted with strips made of shape memory alloy
One of the most imperfections of the steel shear wall is out of plane displacements that cause severe damage in both structural and non-structural elements. In this paper, the effects of shape-memory alloys on steel shear walls are investigated. First, a numerical analysis using the finite element method in ABAQUS software has been carried out according to an experimental test. The results of the numerical analysis have been verified with experimental results. Next, shape-memory alloy fibers have been added vertically and horizontally to various parts of the steel shear wall. The results show that retrofitting with the shape-memory alloy reduces the out-of-plane displacement of the steel shear wall under both cyclic and seismic loadings. Besides, the buckling load in the steel shear wall increases when it is retrofitted with the shape-memory alloy. Also, the total out-of-plane movement (accumulated absolute displacements) of the steel shear wall and non-structural damage are controlled by the characteristic of a shape-memory alloy material called “super-elastic”.