# Buckling-Restrained Bracing System with Ultra-High-Performance Fiber Concrete
## 1 Introduction  
Current construction techniques generally use lateral bracing systems in the form of tension-only bracing or rigid tension-compression steel bracing to increase the stiffness of structures. While conventional lateral cross-bracing can be used for both lateral excitation applications, the cyclic compressive force applied to steel braces during seismic events has resulted in the recent development of the buckling-restrained bracing (BRB) system. However, research on buckling-restrained braces (BRBs) has indicated that once the main core fails, they lose their capacity to bear additional loads. Therefore, it is crucial to consider the need for repair or replacement of BRBs after they are subject to severe excitation. One of the primary causes of failure in BRBs is attributed to their significant residual deformation resulting from their low post-yield stiffness. This characteristic can lead to the premature collapse of the brace during vibrations. Investigations into the use of metallic yielding devices as part of the main structural system to dissipate seismic energy were first conducted in 1974 [1]. Introducing steel members with a known yield point and reliable plastic plateau to work as axial, shear, bending, or torsion-type hysteretic dampers was the main idea [2, 3]. The concept of a ductile device, which is able to have a function beyond the frequent elastic limitationsin cyclic loading, led to the seismic energy-dissipating systems that are used today [4]. Concentrically braced frames (CBFs), eccentrically braced frames (EBFs), and buckling-restrained braced frames (BRBFs) are three types of braces that are made in order to fulfill this need [5]. Generally, structures are subject to considerable cyclic forces during a seismic event. Buckling-restrained brace (BRB) devices are implemented in order to enhance the resistance of braced frame structures by dissipating the energy. BRBs are made of a slender steel core constantly supported by a filler material casing. After a high-intensity earthquake has occurred [6; 7; 8; 9; 10; 11], the core component of the structure can undergo complete yielding and failure, resulting in the loss of its functionality. As a consequence, the structure remains unbraced, which can potentially lead to unexpected failure or collapse of the main structural elements. Testing and evaluation are compulsory when designing and ensuring quality control. Although experimental tests can accurately assess the behavior of anti-seismic devices, they require significant financial resources and may lengthen the actual project schedules. Numerous research studies have been conducted over the past decade, leading to the development of various types of buckling-restrained braces (BRBs). Due to the complexity of these devices, it is essential to complement numerical estimations with experimental studies for reliable results. Without proper validation, numerical estimations may not be entirely dependable. However, validated and verified models can play a crucial role in accurately predicting the behavior of BRBs, making them indispensable in the design process for these devices. Due to the mechanical difficulties and the need to keep to the design process, mainly empirical and semi-empirical models have been proposed. [PERSON] (2009) offered an analytical method for BRB rigidity requirements [12] and [PERSON] (2011) presented an out-of-plane-deformations stability model [13]. [PERSON] (2012) investigated whether bracing systems affect end rotation for global stability designs [14] and also studied the local buckling behavior of all-steel BsRBs [15]. [PERSON] (2015) also worked on all-steel BRBs analytically [16]. Other researchers have developed more intricate, fundamental finite element models. These numerical models were developed to highlight specific BRB design details to illustrate behavior approximations. [PERSON] (2010) investigated the local stiffness of the hollow section in BRBs [17].