The Hidden Engineering Beneath Bangkok’s Pixel Tower

From the streets around Chong Nonsi station, King Power Mahanakhon looks like a skyscraper interrupted halfway through loading. A ribbon of rectangular recesses twists around its glass exterior. Corners disappear, terraces emerge, and the upper floors seem to dissolve into the Bangkok sky.

That apparent instability is the building’s signature. But the more revealing engineering story begins below the pavement: how to support a tower roughly 314 meters tall in a city underlain by compressible sediments, then construct its enormous concrete foundation without the hardening process damaging it.

The facade makes a spectacle of missing material. Underground, the task was to place material with extraordinary care.

Designed by Ole Scheeren and developed by PACE, MahaNakhon celebrated its completion on August 29, 2016, with the light show “Bangkok Rising: Night of Lights.” Bouygues-Thai, responsible for the tower’s structural design and construction, records its structural topping out in March 2015 and completion of facade work later that year. Those milestones show how much work separates reaching the roof from finishing a landmark. Bouygues-Thai’s project account

The building combines residences, a hotel, retail and observation spaces beside one of central Bangkok’s elevated railway stations. Its strange silhouette belongs to an intensely practical piece of urban real estate, with different uses stacked vertically on a constrained city site.

Where it is

King Power Mahanakhon, 114 Narathiwas Ratchanakarin Road, Silom, Bang Rak, Bangkok, Thailand. BTS Chong Nonsi station, Exit 3. Official visitor information

The pixels are inhabited architecture. Scheeren’s practice describes the recesses and projections as a way to introduce terraces, balconies and glass rooms into the tower. They break the repetition of a conventional glass shaft while opening apartments toward the city and Chao Phraya River. From a distance, the building reads as a digital image. Closer up, that image resolves into places where people can stand, sit and look outside. Büro Ole Scheeren’s design description

This is an expensive-looking visual trick with a spatial purpose. The carved surfaces bring outdoor rooms into a building type more commonly associated with sealed interiors. At its base, terraces, a plaza and the neighboring Cube retail building extend that architectural language toward the street and transit connection. The tower’s irregularity continues down to the scale of a pedestrian.

Below that public setting is a very different landscape. Bangkok occupies part of the Chao Phraya delta, where layers of clay alternate with water-bearing sand and gravel. A recent groundwater and subsidence study describes these interbedded sediments as central to the region’s susceptibility to sinking. Groundwater extraction can reduce pressure in the subsurface, allowing clay layers to compact. Research on Bangkok’s groundwater and subsidence

That regional process needs to be distinguished from the settlement caused by an individual building’s loads. Both concern movement in the ground, but they operate at different scales. A deep foundation addresses the tower’s support conditions; it does not freeze the surrounding delta in place.

For a tall building, uneven movement is especially consequential. If supports settle by different amounts, the structure above must accommodate those differences. The engineering objective is controlled, compatible movement, rather than an absolute promise that nothing will move.

MahaNakhon’s engineers specified 129 rectangular concrete barrette piles extending about 65 meters below grade into Bangkok’s second sand layer. A massive reinforced concrete mat connects them, reaching a reported thickness of 8.75 meters. In their 2015 technical paper, Bouygues-Thai engineers describe modeling the interaction between the piles, mat and soil, including how neighboring piles affect one another’s stiffness and share load. The structural team’s technical paper, available as a reproduced copy

The foundation is therefore more than a collection of long concrete legs. It is a connected system whose parts respond together. The thickness of the mat provides the capacity to transfer forces between the tower above and its buried supports.

Yet making a foundation larger introduces another challenge: concrete produces its own heat.

Cement hardens through reactions with water called hydration. Those reactions release energy. In a relatively thin element, heat can escape more readily. In a large concrete mass, the interior can remain much hotter than the exterior. As temperatures change, different parts try to expand or contract by different amounts.

If those movements are restrained, stresses develop in concrete that is still gaining strength. A large temperature difference between the center and surface can cause cracking. The American Concrete Institute identifies this thermal behavior as the defining concern of mass concrete, and describes lower placement temperatures and changes to the cementitious mixture as ways to control it. ACI’s explanation of heat of hydration

The counterintuitive consequence is that simply cooling the outside quickly can worsen the mismatch. Temperature control means managing the relationship between surface and interior, as well as limiting the heat generated in the first place.

At MahaNakhon, the team replaced some cement with fly ash, cooled ingredients and insulated the placed concrete. Temperature sensors tracked conditions inside the foundation. Construction proceeded through 12 pours, each requiring about 12 continuous working hours, coordinating heat control with the practical limits of concrete delivery in central Bangkok. The technical account makes clear that the foundation was a sequence of managed placements, rather than one gigantic uninterrupted pour. Structural design and construction account

These details change how the tower’s drama reads. Its apparent gaps are visible from across the neighborhood. The timing, mixture and temperature of its foundation concrete are invisible to almost everyone who visits, yet they were essential to realizing the architecture above.

At the summit, the building turns structural confidence into a visitor experience. The SkyWalk includes a glass tray 310 meters above the ground, while its highest viewpoint reaches 314 meters. Looking through that transparent floor makes height feel immediate: the street becomes something beneath your shoes. Official SkyWalk description

From below, Mahanakhon invites you to wonder where the missing pieces went. From above, it invites you to look down. The engineering story connects those two views, continuing through the pavement into a foundation designed around the ground beneath Bangkok.

Sources

• Bouygues-Thai: MahaNakhon project and construction milestones
• Büro Ole Scheeren: MahaNakhon design and urban context
• Chanvaivit, Ly and Clair: The Structural Design and Construction of the MahaNakhon Tower, 2015, reproduced technical paper
• Linked Data-Driven, Physics-Based Modeling of Pumping-Induced Subsidence with Application to Bangkok, Thailand
• American Concrete Institute: Heat of hydration and the importance of controlling it
• King Power Mahanakhon: Official SkyWalk and location information