Experimental tests on beams and columns constructed of high strength materials

摘要

The high strength concrete (HSC) is a relatively new material of enormous potential. The main characteristics of HSC are high strength and low deformability. To contribute to the study and definition of the strength and deformability characteristics of elements constructed of high strength materials in nonlinear range of behaviour and define a methodology and criteria for use of these materials in seismically active regions, ample analytical and experimental studies were performed in the Institute of Earthquake Engineering and Engineering Seismology, IZIIS, Skopje. In the period 1992―1998, the investigations were concentrated on definition of a technology for obtaining HSC, exclusively from own (domestic) resources. In that period, ample analytical and experimental investigations of physical-mechanical characteristics of constituent components (cement, aggregate and additives) as well as concrete as material were done. Since 1998 till now, the second phase of the project has been going on, within which frames, beam and column elements have been designed and constructed of high strength materials (concrete and reinforcement). To define the behaviour of elements in linear and nonlinear range, ample analytical and experimental investigations have been performed. The experimental investigations were carried out in the Dynamic Testing Laboratory of IZIIS, under quasi-static regime of loading. In the frame of the experimental programme, investigations are performed involving design and construction of models of beams and columns. The models were constructed of high strength materials (concrete and steel), to a geometrical scale of 1:1. The beam models had proportions of the cross-section of 25/40 cm, and the column models had proportions of the cross-section of 30/30 cm. Varied parameters were: concrete compressive strength, percent of the reinforcement and yielding strength of the vertical and horizontal reinforcement. Ribbed reinforcement RA400/500 and ULBON steel SBPD 1275/1420 produced by Japanese company NETUREN, were used for reinforcement of the models. Presented in the paper shall be details of the models of the beams and columns as well as part of the results obtained from the experimental tests.