BEHAVIOUR OF SHEAR LINK OF WF SECTION WITH DIAGONAL WEB STIFFENER OF ECCENTRICALLY BRACED FRAME (EBF) OF STEEL STRUCTURE

• Main Author: (NIM : 35006003); Tim Pembimbing : Prof. Ir. R. Bambang Budiono, ME,Ph.D.; Ir. Muslinang, YURISMAN
• Format: Dissertations
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/17700
• Institution: Institut Teknologi Bandung

Link is the most critical element in steel structures with eccentrically braced frame (EBF), seismic energy dissipation in EBF steel frame structures occurring through <br /> <br /> <br /> a process of plastification on the link element. Various efforts to improve the performance of the link in EBF system have been carried out by several previous researchers such as by adding the thickness of flanges and vertical stiffeners. However, the study needs to be further developed in order to obtain the behaviour of link gaining the optimum performance. <br /> <br /> <br /> This dissertation presents the results of research on the behaviour of shear link WF section with the addition of diagonal bracing plates fitted to the web section of the section. With the installation of a plate stiffeners with a certain thickness diagonally, it is expected to be able to increase the strength, the stiffness, ductility and energy dissipation capability. Some of the main parameters that were examined in this study are: the distance of vertical stiffener, diagonal bracing thickness and the placement of stiffener plate of geometric model to the web of WF section. <br /> <br /> <br /> In principle, this study aims to conduct a comprehensive review of several significant parameters related to the ability of shear links in conducting seismic energy dissipation, especially the use of diagonal stiffener on the web of the shear link WF section. In specific, the purposes of this research are described as follows: 1) to understand the mechanism of absorption of seismic energy in the steel structures of eccentrically braced frame (EBF). 2) To investigate the behaviour of some parameters considered significant in giving influence on the <br /> <br /> <br /> performance of the shear links under cyclic loading. 3) To investigate the hysteretic behaviour the use of diagonal stiffeners installed on the web of WF profile on the performance of the shear links. <br /> <br /> <br /> The two methods to achieve the purpose of this study are: a numerical study using nonlinear finite element analysis and experimental studies. The numerical study is conducted to identify parameters before experimental works. The numerical analysis is also used further to study the stress distribution after being validated accurately with the experimental studies. Numerical study was performed by <br /> <br /> <br /> making a few element models to shear link in which the links are modelled as shell elements of CQUAD4 and provided fixed support on each node on both ends of the beam itself. However, at one end of the beam is given one degree of <br /> <br /> <br /> freedom, namely: displacement in y-axis direction. In each model of test object is provided with load displacement control with static monotonic and cyclic loading. <br /> <br /> <br /> The validation of the specimen behaviour between numeric and experimental analysis is expressed in the form of relationship between loads vs. displacement. This numerical study was carried out with the aid of computer software MSC / NASTRAN version 70.5. <br /> <br /> <br /> Experimental study is carried out by making three specimens of shear link, where the dimensions and shape of the specimen is adjusted to the model created in numerical study, specimen 1 is the link shear with diagonal stiffener thickness of 4.2 mm, specimen 2 is the link shear specimen with AISC standard without diagonal stiffener and specimen 3 is the link shear with diagonal 8 mm thick stiffeners. Loading protocol given in the experimental study refers to the loading standard of AISC 2005, loading of the specimens were performed by using displacement control system. <br /> <br /> <br /> The comparison of the performance of individual specimens is performed at 0.03 radians of rotation because in such condition, the three specimens are considered stable meaning that all parts of the specimens undergo inelastic deformation and have not undergone failure. <br /> <br /> <br /> The objective of the numerical study is to analyse stress distribution of the specimen where the study cannot be carried out in the experimental works. Therefore, the numerical analysis should be validated accurately with the <br /> <br /> <br /> experimental work first. Basically, numerical and experimental test results show the same trend in which the placement of diagonal stiffener plate on the web of WF profile can improve the link performance in terms of: strength, stiffness, ductility and energy dissipation. However, due to limitations in testing and the ability of computer software in modelling, there is still a difference between numerical and experimental results, even though it is not significant. The difference occurs because the stress concentration in the welded joints around the support specimen resulting in a premature failure. In this study these phenomena cannot be modelled numerically. Under numerical analysis, the principal tensile stress distribution only shows the largest stress concentration in this area but it cannot predict the failure condition. From the numerical study, the stress distribution is capable to detect the plastification behaviour at the area of the web <br /> <br /> <br /> and the diagonal stiffener.