Библиографический список
Гиппократ. Клятва. Закон о враче. Наставления. / Пер. с греч. В.И. Руднева. М.: Современный литератор, 1998. 832 с.
Котельников В.П. От Гиппократа до наших дней. М.: Знание, 1987. 112 с.
УДК 691.328
студент Волченко А. И.
Сибирская государственная автомобильно-дорожная академия (СибАДИ), Омск
Abstract. Results of test, joints of elements of construction designs are given. Prefabricated joints standards are used.
Аннотация. В статье приводятся результаты испытания сварных швов в строительных конструкциях.
Keywords: rolling beam, welded joint, slips, welding seam.
Ключевые слова: прокатная балка; сварной шов; сварное соединение.
APPLICATION OF PREFABRICATED JOINTS IN ROLLING BEAMS
The strength of a butt weld subjected to axial forces is analyzed on the assumption that the stresses are uniformly distributed over the cross-section of the weld. When the weld is defective the force field inside the plate is not uniform and induces an additional bending moment and a dangerous concentration of stresses. To eliminate this a bead weld is applied after thorough cutting out of the slag inclusions at the root of the weld.
The section of a butt weld used for investigations, when the weld is located perpendicular to the centre line of the element (a square joint), is taken equal to the area, but without regard to the strengthening bead weld below and the deposited bead on top, i.e.,
Aw = lw t,
where, t is the minimum thickness of elements being welded; lw is the design length of weld, equal to the actual length less 10 mm (allowing for the formation of a crater and poor penetration at the ends of the weld). If the weld is extended to the backing strip these 10 mm may not be subtracted.
The stress in a weld is checked by means of the expression:
σw = N / Aw = N / lw t ≤ Rwγc,
in which Rw is the design tensile or compressive strength of a butt weld. The design tensile strengths of square-groove butt joint welds, made by manual or semi-automatic welding, and with ordinary methods used to control the quality of the welds, are lower than the strength of the base metal at the joint. For this reason the stresses in the base metal cannot be utilized completely. The design of a skew joint has a strength equal to that of the base metal. The angle between the direction of the axial force and that of the skew weld should not exceed 65o (generally the angle of 60o is employed). With such an angle the strength of the joint does not have to be checked.
Lap joints. A lap joint can be made with or without straps, using fillet welds. Depending upon their arrangement relative to the forces acting on the elements, fillet welds can be side (located parallel to the forces) and end or edge ones (located perpendicular to the forces)[1].
That secondary reinforcement should be provided for beams exceeding at a distance measured 2/3 depth from the tension face. The maximum width of cracks arising from flexure may be about two to three times larger than the width of the same crack at the level of surface where the crack originally forms. To safeguard against these crack formation, skin reinforcement is designed on the sides of deep beams to limit the formation of flexural crack widths. Though the principal function of skin reinforcement is to control crack width, it may be employed for providing bending resistance of the section.
Научный руководитель – Г.И. Надыкто, канд. тех. наук, доцент, СибАДИ; Т.Г. Галкина, канд. филологич. наук, доцент кафедры «Иностранные языки» СибАДИ, Омск.