Interviews

Hear what industry leaders have to say about the opportunities and challenges in the Southeast Asian Construction Market in the interviews below.

The Experts Opinion: Ir. Davy Sukamta talks about the Indonesia-1 tower

Ir. Davy Sukamta, Principal at Davy Sukamta & Partners Structural Engineers, President at HAKI (Indonesian Society of Civil and Structural Engineers) and Fellow PE is responsible for the design of Indonesia-1, or Indonesia Satu Tower, one of Indonesia’s tallest buildings currently under construction in Jakarta.

Q: What is the rationale behind the design and construction of the Indonesia-1 Tower?

A: “Located in the most prominent area of Jakarta, this two-tower complexmust offer state of the art office spaces, along with high-end apartment units and retail space. The twin supertall buildings are meeting this purpose. The development will also support the vertical urban trend in Jakarta, being one of the world’s most populous urban agglomerates, with its 10 million inhabitants”.

Q: What challenges are you facing in the development of Indonesia-1?

A: “The height of the building, being 303 meters above ground, falls under the supertall category in the CTBUH definition. For a building of this scale, lateral load plays a very important role, and the design of the structure must address this issue from phase one. Moreover, Indonesia-1 has a huge basement structure: 7 levels rooted in a 25-meter deep excavation in a dense urban area. The design of this deep basement’s structure in Indonesia is an engineering feat on its own. The huge weight of the building is another challenge, since it will be built on a soft clay soil condition”.

Q: What systems and technologies are you putting in place for mitigating the risks of seismic effects on the tower? 

A: “The main challenge for effectively mitigating the risks of seismic effects on a supertall building is to determine how much strength and deformation capacity should be provided to the structure. Indonesia-1 was designed to meet and exceed the Indonesian Seismic Resistant Design Code, SNI 1726:2012. It uses RC coupled wall and outrigger as the lateral resisting system. We developed a performance-based design to evaluate the behavior of the structure when subjected to strong earthquake ground motion. By applying this rigorous analysis we can "fine-tune" the structural design by allocating strength to selected structural components while allowing the earthquake energy dissipation on the ductile structural components. RC coupled wall and outrigger effectively provide the required stiffness and stability to the building. Damage control is assured by limiting interstory distortion to an acceptable level. This structural scheme is simple to construct and contributes significantly to the speed of construction.”

Q: What are the key aspects to consider when developing a supertall building in Indonesia?

A: “Local practice and availability in the Indonesian market shall be taken into consideration when defining respectively construction techniques and structural materials. Speed of construction is a key parameter in developing a supertall building, and the structural design must address the time issue from the very beginning. Selection of the structural system is another very important aspect to consider in the design phase.”

Q: What role does the total cost of ownership play in the design of the tower?

A: “The total cost plays a major role in determining the success of a project of this scale. Cost of construction material, overhead and preliminary cost of the project during construction, cost of money, speed of construction and delivery time must all be carefully evaluated since phase one of the project. The total cost of ownership plays is in fact critical for the development of the structural design of the tower. This is reflected in the efficient and economical selection of the structural material and system of supertall buildings.”

Q: What challenges and opportunities does a mixed use tower like Indonesia-1 offer?

A: “Being located in a prime area of Jakarta, close to five-star hotels and high-end retails, a mixed use development like Indonesia-1 offers a unique opportunity to work and live conveniently in Jakarta. On the other hand, developing a costly building of this type and scale creates challenges in the design coordination effort: each occupancy type has in fact different requirements and preferences. Therefore, we must find efficient solutions to accommodate both business and residential uses, while keeping in mind the simplicity of the structural system.”

Q: What are the Indonesia-1 Tower’s major innovative features?

A: “The design of Indonesia-1’s structure and foundation is the result of an innovative approach. We developed a performance-based design, employing high strength concrete and high strength steel to reduce the amount of material used in the construction, and a mix of concrete-steel for the main structural material of the tower to reduce the total weight of the building and save construction time – where most other buildings use a conventional RC structure. We implemented the modern coupled core-wall and outrigger structural system and post-grouted high capacity bored-pile for the foundation system to save on cost and construction time.

To speed up the construction, we are utilising a steel erection column in the RC column, and applying the “synchronous rise different height” construction method in the design. We also designed and detailed the column components for speed and ease of construction, allowing the location of tremie pipe for concrete casting, while meeting the seismic detail requirements. All these innovations are strongly contributing to reduce both cost and construction time.”

Ir. Davy Sukamta hosted a session dedicated to “The Design of a supertall building. The Indonesian Experience: Indonesia-Satu Tower” at The Big 5 Construct Indonesia 2016.

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