| description abstract | Concentric braced frames are one of the most effective measures for controlling damages induced by earthquakes in buildings. In compression, conventional concentric hot-rolled steel braces buckle under seismic loading, which leads to catastrophic failure of buildings. The buckling in hot-rolled braces develops pinched hysteresis behavior, which leads to a lag in the total energy capacity. This limitation of hot-rolled steel braces drives the present study to use pretensioned steel cables as braces in concentric braced frames. The performance of the proposed self-balancing pretensioned steel cable braces system is assessed by comparing it with conventional concentric braces utilizing stocky hot-rolled steel braces. Two types of steel cables are used in this study: a self-balancing pretensioned steel rope brace system and a self-balancing pretensioned spiral strand steel cable brace system. A total of 57 models (19 each for hot-rolled steel braces, spiral strand steel cables, and steel ropes) are analyzed in SAP 2000 and are designed following Indian standards, maintaining a constant ultimate compressive capacity of the braces in all systems. The performance in all systems (hot-rolled steel braces, spiral strand steel cables, and steel ropes) is examined by total strain energy capacity, fundamental time period, base shear demand, interstory drift, self-centering capabilities under maximum considered earthquakes, and section size of members. On average, the total strain energy capacity of the steel rope system is enhanced by 1.5 and 2 times that of the spiral strand steel cables and hot-rolled steel brace systems, respectively. Similarly, the base shear demand in steel rope system is reduced by 13% and 39.2% of the spiral strand steel cables and hot-rolled steel brace systems, respectively. Pretensioning in cables eliminates brace buckling and ensures the system’s self-centering capability. Finally, a design guideline for the self-balancing pretensioned steel cable braces system following Indian standards is proposed. | |
