QUOTE(iGamer @ Mar 2 2023, 09:37 AM)
Do they plant many trees on the elevated roads though?
Concrete's main witness is the steel bars inside must be protected against moisture and water, moisture and water will cause the steel bars to rust, rusted steel bars will expand and crack the cement, hence the concrete structure is compromised.
Architect is not botanist, they knew little of the plants that they will put there, most probably the developer will chose nice looking plant without in depth knowledge of the plant. Since planting on concrete structure is a new trend, there will be lots of mistakes these expert "architect" will learn over the years, so be ready to become the lab rats of planted building...

Dynamic loads (i.e. loads that are constantly changing and) are actually way detrimental on reinforced concrete than any tree roots induced pressure. Swimming pools, although do not have dynamic loads, are exposed sun and water pressure that is more immense than moisture from earth. Nevertheless, with proper design consideration and safety factor, effects can be reduced to insignificant.
That is why design consideration is important when it comes to trees. Not sure about other countries, but Malaysia always skimp or overlook on the rc design when it comes to planting trees. In example, common in residential condos to have 600mm depth structure for earth and trees (which imo isn't enough for bigger trees). Concrete's main purpose is to resist compression, while rebars for tension. Both of these elements work together, any lacking of either both will cause cracks due to tension or compression 'failure'. With proper design and workmanship, concrete can be watertight and movement resistant - but that also depends on the whole structure movement as well, as highrises have movements.
Landscape architect is do actually help in trees rooting issue (i.e giving info on each tree's so-called maximum weight and root length for S.O's and structural engineer design consideration). Having plants in structures actually had been encouraged and practiced here over a decade ago, its only the requirement of landscape experts that is quite new....
What still surprises me is that reinforced concrete structure was said not to able to withstand the power of tree roots, which could spell out design error. Also botanist may know how to maintain a plant on normal ground, not necessarily on space tight structures.