This "under-cooked" rock is found near Liku area, Miri, between at about 29m below ground level. The rock looks like sun-dried mud and does not possess much compressive strength.
Saturday, 30 January 2016
Friday, 29 January 2016
Structural Safety of a Bird
If you look at the legs of this bird and do a structural calculation on the slenderness, perhaps they are on the unsafe side. Anyway, bird's life is not valuable, nobody will bother.
But if I put up a building with such proportion. It is likely that the occupants will not feel safe and perhaps feel uneasy to dwell/venture inside.
Perception/feeling can affect the occupants' psycho. I designed a structure in Miri thirty years ago, the columns provided appeared slender. Some occupants felt unsafe and even a lorry passed by would complain due to slender columns and doubted about safety. A simple shrinkage wall crack would also alarm them.
It is therefore important in the design to consider local people's psyche, it does no cost much to provide bigger columns, for example increase from 300x300 size columns to 350x350 size.
If you look at the legs of this bird and do a structural calculation on the slenderness, perhaps they are on the unsafe side. Anyway, bird's life is not valuable, nobody will bother.
But if I put up a building with such proportion. It is likely that the occupants will not feel safe and perhaps feel uneasy to dwell/venture inside.
Perception/feeling can affect the occupants' psycho. I designed a structure in Miri thirty years ago, the columns provided appeared slender. Some occupants felt unsafe and even a lorry passed by would complain due to slender columns and doubted about safety. A simple shrinkage wall crack would also alarm them.
It is therefore important in the design to consider local people's psyche, it does no cost much to provide bigger columns, for example increase from 300x300 size columns to 350x350 size.
Pre-stressed Concrete Girder Beams
Have not seen such long bridge pre-stressed beams being constructed since the Penang Bridge, they are more than 40m length. I saw them at Sri Aman a few days ago.
I just wonder how are they going to be launched as the site is quite rural, and each beam weighs about 75 tons.
Anyway, the launching is unlikely to be done in near future as the pier in the river has not been constructed, From the notice board, this bridge started in 2013, almost three years already.
Have not seen such long bridge pre-stressed beams being constructed since the Penang Bridge, they are more than 40m length. I saw them at Sri Aman a few days ago.
I just wonder how are they going to be launched as the site is quite rural, and each beam weighs about 75 tons.
Anyway, the launching is unlikely to be done in near future as the pier in the river has not been constructed, From the notice board, this bridge started in 2013, almost three years already.
Nature's Rubbish Sweepers - Ants
The termites are hardly dead. They just flew out from the nest in swarm and attracted by light, fluttering round the lamp bulb. Then they dropped on the floor.
The ants came immediately, busily carrying them back to its nest despite of the giant sizes. Soon the floor was clear.
I do not know the meaning the life for these flying termites. After all the processes of metamorphosis, flew out of the nest and just died on the floor. Perhaps, as long as one or two managed to escape into safe places, they would start another new colonies and the species would survive. It must be, otherwise these insects would have long gone from this planet.
What about human, what is the meaning of life too?
Born, eat, learn, grow up, educate, work, earn money, marry, buy house/cars, have children, raise up children, retire, face sicknesses, died and finally bury. Bacteria and acidic water will help to clear our bodies and even bones from this planet.
The termites are hardly dead. They just flew out from the nest in swarm and attracted by light, fluttering round the lamp bulb. Then they dropped on the floor.
The ants came immediately, busily carrying them back to its nest despite of the giant sizes. Soon the floor was clear.
I do not know the meaning the life for these flying termites. After all the processes of metamorphosis, flew out of the nest and just died on the floor. Perhaps, as long as one or two managed to escape into safe places, they would start another new colonies and the species would survive. It must be, otherwise these insects would have long gone from this planet.
What about human, what is the meaning of life too?
Born, eat, learn, grow up, educate, work, earn money, marry, buy house/cars, have children, raise up children, retire, face sicknesses, died and finally bury. Bacteria and acidic water will help to clear our bodies and even bones from this planet.
Tuesday, 12 January 2016
River Gravels
These gravels appear to be better aggregates for making concrete compared to the powdery limestone aggregates. It took hundreds or even thousands of years to grind the big rocks to these small gravels. But in Sarawak, most of the streams and rivers pass though sedimentary rocks and therefore these gravels are mainly of Sandstone, Mudstone, Siltstone and Limestone origins. The rocks are not hard enough to withstand heavy pressure. The aggregates are not suitable to make high strength concrete. But they are commonly used in rural regions for making low strength concrete not exceeding 25N/sq.mm. Most of the old buildings used the river gravels when quarried aggregates were not available. But the new building codes are getting stringent that some of the gravels may not be able to pass certain aggregate tests.
These gravels appear to be better aggregates for making concrete compared to the powdery limestone aggregates. It took hundreds or even thousands of years to grind the big rocks to these small gravels. But in Sarawak, most of the streams and rivers pass though sedimentary rocks and therefore these gravels are mainly of Sandstone, Mudstone, Siltstone and Limestone origins. The rocks are not hard enough to withstand heavy pressure. The aggregates are not suitable to make high strength concrete. But they are commonly used in rural regions for making low strength concrete not exceeding 25N/sq.mm. Most of the old buildings used the river gravels when quarried aggregates were not available. But the new building codes are getting stringent that some of the gravels may not be able to pass certain aggregate tests.
Limestone Aggregates
I bought another 5 tons of 20mm aggregates for the concrete work from a different supplier costing RM200. It looked al right from outside, dominated by 20mm nominal size, other than laminated with some calcite. But when I scooped in, the aggregates seemed to have too have much fines and the black rock materials looked more like metamorphosed Mudstone or Phyllite.
I took some to the soil laboratory and the aggregates reacted strongly with the hydrochloric acid. They are really limestone materials. But they contain too much smaller materials (2mm to 10mm size), perhaps more than 70%. It means more cement is needed to make a specific strength concrete. Until the cube tests being done, I am not sure whether the aggregates are suitable for the structural concrete.
Obviously, limestone aggregates are not recommended for foundation, marine works and concrete exposed to rain.
I bought another 5 tons of 20mm aggregates for the concrete work from a different supplier costing RM200. It looked al right from outside, dominated by 20mm nominal size, other than laminated with some calcite. But when I scooped in, the aggregates seemed to have too have much fines and the black rock materials looked more like metamorphosed Mudstone or Phyllite.
I took some to the soil laboratory and the aggregates reacted strongly with the hydrochloric acid. They are really limestone materials. But they contain too much smaller materials (2mm to 10mm size), perhaps more than 70%. It means more cement is needed to make a specific strength concrete. Until the cube tests being done, I am not sure whether the aggregates are suitable for the structural concrete.
Obviously, limestone aggregates are not recommended for foundation, marine works and concrete exposed to rain.
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