Wharf Bollards

All wharves and jetties require bollards to tie the ships or boats during berthing. But what is the best materials for making the bollards, concrete or steel?

This concrete bollard, after tens of years service, has stripped itself off through abrasion and weathering. Steel bars are now exposed and soon rust will come in.
Therefore, thick steel cylinder hollow section filled with concrete may be a better choice.

Kuching Metamorphic Rock - Phyllite

There are many types of rocks beneath Kuching City. One of the most common rocks is Phyllite, spreading from Kuching River Front to many other parts of the city. You will not be able to find beautiful rock cores out of the conventional drilling.

The rock  is grey with a characteristic silvery sheen. 

Although the rock appears to make up of broken pieces, but do not expect driven concrete piles to penetrate. Standard penetration tests often produce N= more than 50 blows per 10mm. Concrete piles find difficulty to penetrate even with N=30 blows per 300mm.

Lawas Sandstone (2)

Another borehole was drilled about 20m away from the first borehole and it reached 23.5m before encountering bedrock. 

But this bed rock is mainly fresh as compared to highly to moderately weathered generally at the first borehole. It colour is mainly grey which applies to most bedrocks not stained by the surface ground water.

Lawas Sandstone (1)

At the Lawas town near the market, this slightly orangey brown fractured sandstone core was extracted from about 12m below ground level. 
The light orange-brown colour is due to the stain apparently from reddish brown clayey silt deposited at the joints, probably due to water percolation.

Lawas is at the northern region of Sarawak, close to Sabah. It lies on a younger geological formation compared to the Western or Central Sarawak.

Uniaxial Compression Tests and Deformation Measurements of A Sarawak Sedimentary Rock

We often lack of basic data to solve engineering problems such as foundation design on local rocks. We often assume data and properties obtained from foreign publications based on foreign rocks which often are greatly varied from local conditions, and blindly apply in the analysis.  Perhaps, we are lucky because we always apply large safety factors, but problems occasionally did arise, which resulted in great disputes and costs.

This research paper attempts to obtain some basic properties of a local sedimentary rock, Salak South Sandstone, so as to understand the behaviour of the local rock under uniaxial loading conditions.

Investigation of Severe Settlements of some Single and Double Storey Houses at Bintulu