| Super tall structure will produce significant vertical deformation under the action of concrete shrinkage and creep and other factors. Excessive vertical deformation difference will affect the safety during the construction phase and the suitability in the use phase. Outrigger-truss and mega brace are important lateral force resisting members of super tall structures. After completion of construction, the order of their installation affects the seismic performance. During the construction process, how to properly close outrigger-truss and mega brace in advance is an urgent engineering problem with waiting to be solved. Shenzhen Pingan International Financial Center is the tallest building being built in China. In this paper, taking it as th e background, the vertical deformation of tall structure was analyzed. The time and sequence of closing outrigger-truss and mega brace were analyzed. Outrigger-truss and mega brace were monitored on site. The monitoring method of their additional stress was studied.The factor and reserve compensation of the vertical deformation were analyzed. Considering shrinkage and creep of concrete, the construction process simulation analysis of super tall structures was carried out with Midas/Gen. The change rules of the floor reserved elevation and the vertical member reserved length along structural height were analyzed. The construction of super tall building is complicated and long, with the risk of downtime. The effect of downtime, the construction speed and core tube constructed advance layers to the vertical construction and vertical construction difference of the structure was analyzed. When these factors do not agree with previous set, how to optimize and adjust the reserve compensation was analyzed.The time, sequence and monitoring method of closing outrigger-truss were analyzed. Closing the outrigger-truss in advance can enhance the stability of the structure in construction. But outrigger-truss will produce additional stress. We need to take into account both of them in construction. The reasonable installation time and sequence of the outrigger-truss diagonal web member and chord member were analyzed from the point of that outrigger-truss floor vertical deformation difference changes. At the same time, on t he construction site, the displacement monitoring was made to the outrigger-truss diagonal web member, the stress monitoring was made to the chord member. The evidence and suggestion about closing the outrigger-truss in advance were provided to the construction unit. The monitoring method of controlling outrigger-truss additional stress according to the results of the monitoring was analyzed, which is of high reference value to guide the construction of other super tall building.The time, sequence and monitoring method of closing mega brace were analyzed. The installations of glass curtain wall and mega brace appeared contradictory. The change rule of the mega brace reserved crack width in the construction process was analyzed. It was monitored on site. The possibility of closing the mega brace in advance was analyzed. After closing the mega brace, its stress was monitored. Which was to examine the rationality of closing the mega brace in advance. The monitoring method of controlling mega brace additional stress according to the results of the monitoring was analyzed. Closing the mega brace in advance had sped up the construction progress significantly, it was of high economic efficiency. At the same time, the effect of foundation settlement and gravity to the stress of mega brace was analyzed. |
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