Influence of the Dimensions and Slenderness of Buildings on the Internal Forces of Reinforced Concrete Building Structures under Wind Loads

Abstract

This research investigated the influence of building dimensions and slenderness on the lateral force from wind loads including the bending moment, shear force and deflection of the building structures. In this study, the building structure was a dual system of frame and shear wall whereby the structural plan was set to be symmetry on both main axes. The investigated buildings had length-to-width ratios of 1:1, 1:2 and
1:3, and their heights were 15, 27, 39, and 54 m, respectively. The results of the study showed that wind pressure acting on the building structures would vary with the increasing height of the building and the terrain where the building was located. For suburban terrain, the wind pressure obtained from DPT1311-50 at height of 15 m was higher than those obtained from Ministerial Regulation No.6 (B.E. 2527) and Draft of
Ministerial Regulation No.6 (B.E. 2565). But when the height of the building increased to 27-54 m, the wind pressure from DPT1311-50 at height of 15 m was much less than those given by the two ministerial regulations. If the internal forces were investigated at the structure base, of the buildings with a height of 15 m, the bending moment at the base of load-bearing wall obtained from DPT1311-50 was slightly greater than 1.045 and 1.12 times, respectively compared to those obtained from Ministerial Regulation No.6 (B.E. 2527) and Draft of Ministerial Regulation No.6 (B.E. 2565). However, when the building was taller, the bending moment at the base of wall obtained from DPT1311-50 was smaller when compared to those obtained from other both Ministerial Regulation. Moreover, when comparing buildings with different slenderness (H/W), it
was found that buildings with higher H/W would lead to the higher flexural moment and shear at the base of the load-bearing wall as expected, whereby the proportion of an increase in internal forces of the load-bearing wall was nearly the same for each standard and specification.