Our Design Approach for 100-Storey Building

Meinhardt has leading experience in the engineering design development of ultra-high-rise buildings across Asia. Our design of tall buildings has undergone a constant evolution during the past decade. Our reputation has been built upon our engagement of sound practices, cutting edge technology, listening to the Client’s wishes and responding with creative thought. We bring advancements in material, structural systems and analysis to achieve the most economical and efficient design.

For this particular 100-storey building project, Meinhardt will mobilize our high-rise experts from our group along with our local team and specialists to undertake the design. This advantageously blends our global know-how with local strengths. Our team is capable of providing authority submissions and is flexible to work with international and local architects. The curriculum vitae of our design team are included as a part of this document.

Our team has carefully planned for the design approach described below.

General Structural Provisions

Ultra-high-rise buildings require special structural elements to withstand large wind and earthquake loads. Outriggers and belts will be provided to enable perimeter columns to interact with central lift core walls in a more effective way in resisting the lateral forces.

To determine wind pressures on building envelops and structural elements precisely, it is recommended that a wind tunnel test be conducted for this 100-storey building. The wind tunnel test also advantageously achieves a reduction of the project cost by avoiding overestimating the wind pressures by local wind code or underestimating wind loads in a complex flow field. Meinhardt will be able to introduce qualified wind tunnel test laboratories both locally and internationally.

Super High Strength Concrete

Considering massive weight of this 100-storey building, super high strength concrete will be employed to optimize the size of structural elements and, hence, maximize usable floor areas. Based on our research, the compressive concrete strength of 70-80 MPa will be the highest practical strength that is commercially available while, with proper mix design, it can still maintain the workability and constructability. Using super high strength concrete also advantageously offers the benefits below.

• Substantial cost saving as a result of smaller structural dimensions and reduced reinforcements.
• Shorter time of construction since early strength development of concrete enables early removal of formwork.
• Lower lateral displacements because of higher modulus of elasticity
• Lesser column shortening problem, which is often the case for ultra-high-rise construction

The proposed super high strength concrete will be used at columns and shear walls at lower storeys only. Lower concrete strength can be used at upper column or wall portions, general floor slabs and other structural elements.

Supplemental Damping System

Tall and slender buildings are prone to potential motion problems under wind and earthquake loading. The conventional method of preventing excessive wind-induced motions is to increase the stiffness of the building. However, for a very slender building project, the penalty for increasing the stiffness could mean an increase in material costs and loss of usable floor area required for accommodating larger stiffening elements.

Meinhardt is capable of providing a design alternative using an auxiliary damping system, which is much more efficient way of counteracting tall building motions. Tuned liquid damper (TLD) or tuned mass damper (TMD) are the considered type of the damping system. The damper will be tuned to the natural frequency of the building so that it provides counteracting inertia force in the out-of-phase motion with the building and leads to dissipation of building motions. This substantially reduces the building accelerations which is directly related to occupant comfort.

For this 100-storey building project, an auxiliary damper is potentially needed to cope with substantial wind-induced floor accelerations. TMD system seems more suitable, since it is relatively compact and can be accommodated in limited floor space. Meinhardt’s recent project with TLD is a 68-storey building at 598 Collins Street in Melbourne, Australia.

Foundation System

For very tall buildings in Bangkok, the foundation design becomes crucial because of massive building loads, limited soil strength, and limited depth of piles that can be constructed. Meinhardt has extensive experience in the foundation design for high-rise buildings in Bangkok and Asia. This includes the River Condominium, a 74-storeys building of 258 m tall. The building is located by the bank of Chao Phraya River, having very thick stratum of soft Bangkok marine clay deposit. Meinhardt has provided this building with thick mat foundation on a combination of bored and barrette piles of 70 m deep, in order to transfer massive building loads to a deeper and stronger soil stratum. With advanced analysis of pile group effects, the mat foundation could be designed to distribute superstructure loads to the piles on the entire building footprint.

For 100-storey building project, similar foundation system will be adopted. The pile tip of 70-75 m seems to be the maximum depth for piling construction in Bangkok and may not be sufficient to carry the loads of 100-storey building. In this regard, toe and shaft grouting will be provided to further increase the load-carrying capacity of the piles.

Dr. Praween Chusilp
Associate Director