PSI - Issue 70

Vivek Kumar C et al. / Procedia Structural Integrity 70 (2025) 97–104

101

Fig.4. Maximum storey displacement at different X bracing locations The X-bracing system efficiently reduces displacement across various sections, including the center, corners, and critical areas. At the 15th floor, center displacement in the X-braced system is 34.427 mm in EQx and 46.159 mm in EQy, significantly lower than the unbraced system's 53.628 mm and 63.714 mm. This reduction is vital for stability, especially at higher levels where lateral displacements are more pronounced. The X-braced system offers increased lateral stiffness, crucial for resisting external forces like wind or seismic activity. At Central X bracing, displacement values are lowest across all storeys for both EQx and EQy directions. Corner X Bracing shows higher displacement than the Centre. As storey height increases, the difference becomes more pronounced, indicating increased torsional movement at corners. For Alternate floor X bracings, displacement is more than Central but less than Corner X Bracing. At each storey, Alternate bracing displacement is between Centre and Corners, reducing displacement compared to Corners while being less effective than Centre. Based on displacement values across X-bracing configurations, the Central X-bracing arrangement emerges as the most optimal option for seismic performance in high-rise steel structures. 5.2. Storey Shear When comparing storey shear (kN) in systems without bracing to those with X-bracing, X-bracing significantly reduces shear forces, especially at higher levels. In the unbraced system, storey shear at Story 1 in EQx direction is -666.1919 kN, while in EQy direction, it measures -340.5291 kN. As building height increases, these forces diminish. By Story 15, shear force in EQx decreases to -117.5255 kN, and in EQy, it is -60.0741 kN. The unbraced system experiences greater shear forces at lower levels, with concentrations at corners and other areas due to unrestricted lateral movement. At Story 1, the corner shear in EQx is -668.1735 kN, slightly exceeding center shear of -667.981 kN and surpassing alternate shear of -1534.774 kN.

Table 4. Storey Shear (in kN) in different positions of X bracing

Unbraced

X Bracings – Storey Shear (kN)

Storey

Centre (EQx)

Centre (EQy)

Corners (EQx)

Corners (EQy)

Alternate (EQx)

Alternate (EQy)

EQx

EQy

Base 0 Story1 -666.1919 -340.5291 -667.981 -575.1655 -668.1735 -537.0612 -1534.774 -522.673 Story2 -665.6514 -340.2528 -667.439 -574.6987 -667.6311 -536.6252 -1444.170 -522.250 Story3 -663.4892 -339.1476 -665.270 -572.8312 -665.4616 -534.8814 -1353.565 -520.556 Story4 -658.6241 -336.6608 -660.390 -568.6295 -660.5802 -530.9579 -1262.690 -516.746 Story5 -649.9752 -332.2398 -651.715 -561.1598 -651.9023 -523.9828 -1168.37 -509.972 Story6 -636.4613 -325.332 -638.160 -549.4883 -638.343 -513.0842 -1069.049 -499.388 Story7 -617.0012 -315.3849 -618.641 -532.6815 -618.8176 -497.3901 -966.85 -484.148 Story8 -590.5138 -301.8457 -592.074 -509.8054 -592.2413 -476.0288 -862.118 -463.403 Story9 -555.9181 -284.1618 -557.373 -479.9265 -557.5294 -448.1283 -754.467 -436.308 Story10 -512.1329 -261.7807 -513.455 -442.111 -513.5973 -412.8167 -643.833 -402.016 0 0 0 0 0 0 0