First, the basic characteristics of macro and micro masonry models in numerical analyses of masonry structures are discussed. Afterwards, developed numerical macro and micro masonry models, intended for the nonlinear static and dynamic analysis of unreinforced and confined masonry walls, as well as of masonry-infilled frames, are briefly presented. The models are tested on previously performed experimental tests of masonry-infilled steel frame under horizontal static force and masonry-infilled steel frame on a shake-table. The precision of both models is compared. It is concluded that both numerical models can provide reliable results. However, the macro model has more advantages for wide practical application.

This paper presents results of the experimental study on the behavior of plain and fiber reinforced cement mortars with different fibers under static and impact compressive load. Glass, polypropylene and carbon fibers were used in equal dosage by mass. The impact test was conducted using an impact tower with drop hammer, which represented the modification of the split-Hopkinson pressure bar system, with strain rates ranging from approximately 35 to 60 s^-1. The results of the static test and impact test with two different drop heights were compared and discussed. Among other, it has been concluded that the tested fiber reinforced mortars had no greater static and impact strength compared to the plain mortar. Only their ductility was increased at both static and impact failure. Strengths and ductility of all composite specimens were similar, i.e. without the effect of fiber type. With the increase of strain rate, compressive strength is increased and ductility is decreased for all tested specimens.

This paper provides a research review regarding the creep of ultra-high-performance concrete with or without the addition of fibers. Unlike other similar studies that mainly considered influential factors and their effects on the creep behavior, this research focuses more attention on the analysis of UHPC creep models. For the creep strain assessments of these concretes, the creep models given in the latest standards cannot be used, but it is necessary to modify them to give reliable results, given the rather complex composition of UHPC. Several proposed creep models for UHPC are presented with comparative analysis. The observation is that by varying key parameters such as compressive strength, relative humidity, cross-sectional dimensions, and temperature, there may be major discrepancies between models, so additional experimental investigations are necessary to perform their calibration. In this paper, the parameters α₁, α₂, and γ of FIB Model Code 2010 have been modified in order to obtain a match with other proposed models in terms of the final value of the creep coefficient and the creep curve. The creep coefficient of the UHPC decreases when steel fiber content increases, but it is important to consider the excessive fiber addition because very often it causes an increase in creep strain. The application of thermal treatment at a temperature of 90 °C for 48 h significantly improves the time-dependent properties of UHPC. An analysis of the impact of the steel fiber content, fiber type, thermal treatment, and the age of the concrete under load on strains of UHPC specimens and beams under long-term loads is performed.