Lumped Construction Sequence for Column Shortening Analysis in High Rise Building with Outrigger System

Pratiksha Kumar Pawar; Sanjay S. Jamkar

Abstract

The exact value of column shortening is not a straightforward task. Various parameters are affected on column shortening results like rate of construction sequence and reinforcement ratio. The building should stand with high stiffness and must be able to resist lateral deformation without having discomfort to the user. The excessive drift is controlled by using outrigger system. In high rise buildings, the construction sequence analysis and conventional sequence analysis are used for column shortening of columns. For analysis of high rise buildings, the construction sequence analysis shows very good results as compared to conventional sequence analysis. In this work, the lumped construction sequence method is used for column shortening, and its efficiency is investigated for different lumping ratios are 1/5, 1/10, 1/15, 1/25 of total number of storeys of the building. These different lumping ratios are considered on 75, 90, 120 storey buildings. The model analysis is carried out in ETABS software. The analysis results indicate that the saw-tooth shape of total shortening has occurred, which can be modified by the curve fitting technique. The results of column shortening are nearly matching for the 1F unit model and 1/15 ratio of a lumped model. The lumped models about 1/15 lumping ratio of the storeys of the building is recommended for construction sequence analysis with accuracy of results.

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