Effect of the Bracing System on the Probability of Collapse of Steel Structures under Maximum Credible Earthquake

Simple bracing frames can be divided into two types in terms of concentric or eccentric. Concentric bracing frames are frames that intersect with other structural members at one point in the structure along the bracing members. Otherwise, the braced frame will be eccentric. It is said empirically that due to this type of shaping, eccentric bracing frames exhibit more ductile behavior and concentric bracing frames exhibit more stiff behavior. This behavioral difference caused this study to be numerically computing for five frames, including unique concentric and eccentric bracing frames of 5 and 10 stories and an ordinary 5-story concentric bracing frame. Their tensions and drift ratios should be acceptable for the use of residential buildings. Using the primary two steps of the new PEER probabilistic framework, namely, probabilistic seismic hazard analysis and structural analysis, which leads to the drawing of fragility curves, the probability of collapse is obtained to compare the safety capability of these frames according to their different characteristics against earthquakes. The results show that increasing the ductility or increasing the number of floors or the height of these systems can reduce collapse. Also, according to the results of the probability of collapse obtained in frames with 5-story concentric bracing frames, it can be said that some of the current regulations, which work based on previous approaches of analysis, can lead to unsafe structures with a high probability of collapse.

PERBANDINGAN SIMPANGAN GEDUNG LANTAI RENDAH DENGAN MENGGUNAKAN 2 TIPE BRESING

Indonesia is one of the areas where earthquakes often occur, one reason is that Indonesia is located on the border of the oceanic plate, namely the pacific ocean and the continental plate, namely the Eurasian continent. Where in these areas plate shifts often occur which cause frequent earthquakes.In minimizing casualties due to building failure due to earthquakes, one of them is necessary to make a building that has sufficient ductility so that in this study using a steel structure building.In steel structures, to make the structure more resistant to lateral loads, it is necessary to apply bracing. In this study, we try to compare the eccentric and concentric bracing displacement in steel structure buildings.Based on the results obtained from the comparison of these displacements, it is found those displacements due to eccentric bracing is smaller than the concentric bracing AbstrakIndonesia termasuk daerah yang sering terjadi gempa, salah sebabnya karena wilayah Indonesia terletak di daerah perbatasan lempeng samudera yaitu samudera pasisfik dan lempeng benua yaitu benua Eurasia. Dimana di daerah tersebut sering terjadi pergeseran lempeng yang menyebabkan sering terjadi gempa.Dalam meminimalisir korban akibat kegagalan bangunan akibat gempa salah satunya perlu membuat suatu bangunan yang mempunyai daktilitas yang cukup sehingga dalam penelitian ini memakai gedung struktur baja.Pada Struktur baja untuk lebih membuat struktur bisa tahan terhadap beban lateral maka perlu diberi bresing. Dalam penelitian ini mencoba untuk membandingkan simpangan bresing eksentrik dan konsentrik pada gedung struktur baja.Berdasarkan hasil yang diperoleh dari perbandingan simpangan tersebut, maka diperoleh simpangan akibat bresing eksentrik lebih kecil di banding bresing konsentrik.

Experimental Investigation Into the Behaviour of a New Replaceable Bracing System

A new bracing system with new features somewhat different from those of the existing ones was devised and is presented. These features comprise some of the advantages of eccentric bracing systems including their ability to dissipate energy through bending of flexural elements while lacking some of the disadvantages of such systems including their inability of being replaced upon damage during events such as earthquakes, etc. While in traditional types of braces, including both concentric and eccentric ones, braces are under axial loading, in this new system they work in a bending capacity. As a result, the sort of flexibility which is introduced in the system in the presence of eccentric braces (definitely at the price of forcing the potential damage to occur and be concentrated at the girders/beams to which such braces are connected), is now provided by the braces and at the price of sacrificing them. Therefore, if the level of damage is such that the damaged element is no longer usable, the replacement of the braces is a more viable and economically justifiable than that of the girders. Moreover, since girders, as part of the deck/floor system, are normally engaged with other elements such as stringers/joists, their replacement may not be practically possible at all. Such bracing systems, called Broken Beam Bracing System (BBBS), have the potential of being used in offshore/onshore structures as originally-used elements or in a retrofit/repair capacity.