Assessment of Effectiveness of Av600P Screw Reinforcement in Compressed Reinforced Concrete Elements

The article is devoted to the research of application of reinforcing steel of a new spiral profile for reinforcement of reinforced concrete constructions. The article presents the results of experimental studies of prism specimens with screw four-row reinforcement with diameters of 20 and 32 mm of class Av600P and concrete of classes B30 and B60 under static compression loading. The purpose of the research was to justify the introduction into practice of the construction of an innovative screw reinforcement profile, which will develop the ideas and principles that have become the basis for the widely used six-row A500SP profile, whose design solution (the absence of longitudinal ribs with the arrangement of transverse protrusions in four rows with the possible formation of a two-start screw thread by them) makes it possible to significantly increase the rejection minimum value of the Röhm criterion (fR ≥ 0.075), which characterizes and determines the strength and deformability of the adhesion of reinforcement to concrete, which determine the strength and crack resistance of reinforced concrete structures, and, consequently, their operational safety and reliability. The coupling joints of screw reinforcement can significantly speed up the process of reinforcing work at the construction site as a result of replacing labor-intensive and expensive welded joints. The results of the research showed the effectiveness of application of new screw reinforcement of the Av600P class for reinforcing compressed reinforced concrete elements made of concrete of classes B30÷B60 with coupling threaded contact, partially contact and non-contact butt joints of the reinforcement

Армирование колонн с использованием различных композитных материалов

The adoption in construction of composite materials made by combining two or more materials to produce a material with improved properties over the separate components has been steadily increasing over the past decades. In the past few years there have been advances in composite manufacturing technology, increased demand for sustainable and eco-friendly building materials, and the need for materials that are lightweight and easy for transportation. For these reason, architects and civil engineers incorporate composites into structural elements to achieve these desired goals and optimize the cost of construction. One of the most common composite materials that was introduced to the industry is fiber reinforced polymer (FRP), produced by combining fibers (carbon, glass, or aramid) with a polymer matrix (epoxy or polyester). FRP materials are lightweight, durable and corrosion resistant, which makes them ideal for use in a wide range of construction applications. This study aims to propose a comparison between four different methods as a viable solution to strengthen and reinforce column structures. The structural behavior of three different composite materials was investigated. One traditional concrete-steel column was tested in the experiment for comparison. The other three columns were reinforced using carbon fiber reinforced plastic (CFRP), glass fiber reinforced plastic (GFRP) and stainless steel respectively. The obtained experimental results were analyzed, and comparison of three different systems of reinforcement for strengthening columns with composite materials was performed.Внедрение в строительство композитных материалов, изготовленных путем объединения двух или более материалов с целью получения материала, обладающего улучшенными свойствами, по сравнению с отдельными компонентами, неуклонно растет в течение последних десятилетий. За это время произошел прогресс в технологии производства композитов, увеличился спрос на устойчивые и экологически чистые строительные материалы, а также потребность в материалах, являющихся легкими и удобными для транспортировки. По этой причине архитекторы и инженеры-строители включают композиты в конструктивные элементы для достижения желаемых целей и оптимизации стоимости строительства. Одним из наиболее распространенных композитных материалов, представленным в промышленности, является армированный волокнами полимер (FRP), полученный посредством объединения волокон (углерод, стекло или арамид) с полимерной матрицей (эпоксидная смола или полиэстер). Материалы FRP легкие, прочные и устойчивые к коррозии, что делает их идеальными для использования в самых разных областях строительства. Исследование нацелено на то, чтобы сравнить четыре различных метода в качестве жизнеспособного решения для укрепления и усиления конструкций колонн. Изучено структурное поведение трех различных композиционных материалов. В эксперименте для сравнения испытана одна традиционная бетонно-стальная колонна. Остальные три колонны усилены с использованием углепластика, стеклопластика и нержавеющей стали соответственно. Полученные экспериментальные результаты проанализированы, выполнено сравнение трех различных систем армирования для усиления колонн композитными материалами

Reinforcement of columns using different composite materials

The adoption in construction of composite materials made by combining two or more materials to produce a material with improved properties over the separate components has been steadily increasing over the past decades. In the past few years there have been advances in composite manufacturing technology, increased demand for sustainable and eco-friendly building materials, and the need for materials that are lightweight and easy for transportation. For these reason, architects and civil engineers incorporate composites into structural elements to achieve these desired goals and optimize the cost of construction. One of the most common composite materials that was introduced to the industry is fiber reinforced polymer (FRP), produced by combining fibers (carbon, glass, or aramid) with a polymer matrix (epoxy or polyester). FRP materials are lightweight, durable and corrosion resistant, which makes them ideal for use in a wide range of construction applications. This study aims to propose a comparison between four different methods as a viable solution to strengthen and reinforce column structures. The structural behavior of three different composite materials was investigated. One traditional concrete-steel column was tested in the experiment for comparison. The other three columns were reinforced using carbon fiber reinforced plastic (CFRP), glass fiber reinforced plastic (GFRP) and stainless steel respectively. The obtained experimental results were analyzed, and comparison of three different systems of reinforcement for strengthening columns with composite materials was performed

EXPERIMENTAL STUDIES OF THE WORK OF NAILED CONNECTIONS

This study is devoted to one of the most common types of wooden structural elements joints - nailed connections. The article presents the results of experimental studies of two types nailed connections on metal plates: traditional connections without bushings and connections, reinforced (modified) with pressed-in fiberglass bushings. The methods of mathematical planning of the experiment were used during the test. That allowed to significantly reduce the number of tested samples of connections and to obtain mathematical dependences in the form of response functions for such characteristics as breaking load Nt and load NI-II, corresponding to the upper boundary of the elastic behavior area of the compound from three factors: the angle between the direction of the acting force and the direction of the wood fibers, the dowel diameter and the wall thickness of the fiberglass bushing. The obtained dependences allow us to evaluate the values of the loads Nt and NI-II for the nailed connections with bushings without testing.According to the experiment planning matrix, 15 types (series) of connections with pressed-in fiberglass bushings and 9 types (series) of traditional nailed connections without bushings were tested.According to the test results, the authors made a comparison of the load bearing capacity and deformability of two types of nailed connections, with bushings and without bushings; the nature of the damage has been established; the analysis of stress-strain state of the middle wooden element in the area of mortise strengthened with pressed-in fiberglass bushing is performed; the conclusion about prospects of application of a pressed-in fiberglass bushings to enhance mortises of new structures and when reconstructing wooden structures in operation