Menara Astra, Jakarta
Standing tall at 270 meters on 2.4-hectares of land, the Green Mark Platinum Menara Astra tower boasts 55 stories that represent the grand vision of Astra.
Windtech Consultants conducted a structural loads and building motion study using the high frequency pressure integration technique. This test enabled an accurate and definitive determination of the wind loads on the structural frame as well as a set of equivalent-static load cases, which could not have been accurately obtained through codes and standards alone. The study also provided an assessment of occupant comfort due to building motion, which was measured against 3 different criteria. Building acceleration was found to be well within limits, which is largely due to the efficient design of the structure.
Façade cladding and internal pressure studies were also undertaken to obtain the façade cladding pressures. This study included a detailed study of the internal pressures and their effect on the inter-tenancy and external walls. A risk analysis approach was used to determine the worst-case result for net façade, internal wall and floor slab pressures between effectively sealed and open/breached façade cases. In general, the wind tunnel results represented pressures which were lower than predicted by the code estimate but also took into consideration the pressure hot spots. This enabled the façade engineer to optimise the design of the façade over the entire building envelope.
A special study was conducted to determine an accurate set of wind-induced load cases for the roof crown. As the roof crown was considered a long-span structure it was important to average the pressures over finite panel areas rather than simply taking the peak pressures from individual pressure sensors which would have resulted in the overdesign of the supporting structure. Thanks to the analysis, the client was able to save on the cost of construction by making reductions to initial estimates that were overly conservative.
A wind environment study was also undertaken. The results from the study indicated that existing conditions for most areas around and within the site satisfied comfort and safety limit criteria. For those areas where exceedances were found, strategically placed impermeable screens and planting was included, effectively mitigating the wind.
Windtech were also involved in providing an accurate and definitive assessment of the impact of wind-driven rain on the critical outdoor areas. Areas affected by wind driven rain were identified and the frequency of rain events affecting these areas was provided. The study enabled an improvement to the design of the canopies which covered the outdoor areas and will lead to more comfortable, dry spaces.