Originally Posted by ravindral

Dear Sir,

At a port, 2 nos 3 km long conveyors are being planned in a single galery. Regarding structure, there is a debate on following options -

1. a concrete deck on piles above sea level and conveyor short supports & stringers to be installed over the concrete deck.

2. Concrete piles and columns, but complete galleery of steel structure.

3. Concrete piles and columns , with concrete beams throught length of conveyor. Walkway platforms, conveyors short supports & stringers will be placed over the concrete beams. Distance betn two columns is expected around 24 m.

Obviously, option 2 is most economical.

Basically, concrete deck or beams is being thought mainly for fear of corrosion in metallic gallery and difficulty in maintaining/painting these structures, as these conveyors will be over sea.

Can experts give on opinion whether concrete columns with metallic gallery over the sea are installed anywhere and whether they are maintainable.

Thanks

Ravindral

As Lyle has so kindly stated the amount of

information is severely lacking.

If you could be more specific in offering

information regarding the location that

would be most tremendously helpful to

aid in helping us help you.

Whether you have neglected to state whether the mining

mass transportation method using the two conveyor belts

is a simple ommision or being deliberately vague is the

another issue in many ways.

What you are asking us for is information that site

specific and needed not just from the national weather service

of the coastal nation described in your initial inquiry

for the following reasons;

1. The tide tables for ebb and high tide on an annual basis.

2. The relevant earthquake data history for the site or local in question.

3. Actual soil conditions/core samples and its load bearing ability.

4. Available infrastructure if any.

Items two and three are foremost as core samples will need to be

taken to verify the subsoil conditions which will reveal the following:

(1) the relevent earthquake data aquired from carbon dating of the subsoil

(2) the tidal wave history from corelog samples which

will describe siltation loading from the tidal wave(s) occuring in

and during the geology timeline of this specific coastal area.

(3) core samples will illustrate the loadbearing ability of the soil

if any and the required amount of preparation required to create a

mining mass transportation corridor using the currently available

methods of ore transport.

You cannot simply plant concrete monopiles in a line whether they

are mixedsoil monopiles or a cast monopile with no geological history.

The same care is required for jetty installations implementing sheet piling

to create an earthern jetty.

The problems include and are not limited to the location and the lack of

information with regard to the conveyor sizing and whether it is inbound

payload or outbound payload.

Help us to help you help us help you.

if you really want the help, you need to contact Mssrs. Lawrence Nordell or Lyn Bates

citing two excellent examples of mining mass stransportation conveying engineering

experience available to aid you with this. You cannot simply implement this without

the proper engineering design and implementation.

You have to have enough surface area to repair the conveyor, transport idlers

needed for replacement, transport gearboxes, pulleys, bearings, electric motors,

generators in order to maintain the system.

The other issue is salt water intrusion on the concrete monopiles AND the steel

reinforcement rod cages which will require the proper formulation of the concrete

if sheet piling is not used to create the monopiles using a neat concrete pouring method

leaving the sheet piling in place.

Its fine to ask us but you have to spend money to make money. ■

Another critical event might be seabirds. They are prolific depositors of unwanted deposits. Concrete will hold up better than steel. You must design for their involvement. Otherwise, you will suffer unexpected maintenance costs. You also left our whether the causeway will require transport vehicles to service the ship and wharf. As others have said, you need a marine engineer as well and conveyor and ship loader/unloader engineer. No use making a long list of don't and bad practice. Get experts to help. Some monumental questions are about the weather, tides and geology, as others have noted. Do you plan to service the ship and dock side equipment with your plan?

GET HELP. ■

Dear Shri Ravindra,

Prior to thinking about the type of conveyor super structure, please also think about following issues:

The conveyor will be between the sea shore and ship berth. The ship berth will have many equipment, for which an access road is always a necessity. Such road, happens to be at least of two lane type, suitable for heavy equipment like crane, trucks and so on. Therefore, such road becomes a heavy civil work. Many times, I have observed that conveyor/s are also placed at the side of such road partly cantilever portion of civil work. Placing conveyor in this manner hardly influences the civil work supporting the road portion. It implies that such arrangement must be found to be economical.

In addition to the conveyor/s, such access road also supports the waterlines etc.

So, think about this matter in a comprehensive manner.

It is also possible that you might have genuine requirement of only conveyors without road, but it looks to be improbable.

Regards,

Ishwar G Mulani.

Author of Book : Engineering Science and Application Design for Belt Conveyors.

Author of Book : Belt Feeder Design and Hopper Bin Silo

Advisor / Consultant for Bulk Material Handling System & Issues.

Pune, India.

Tel.: 0091 (0)20 25871916

Email: parimul@pn2.vsnl.net.in ■

As the other respondents have pointed out, your issue is highly complex.

We are left unaware as to the climatic influences. I suggest you read an old paper from Sir Alexander Gibbs & Associates (should still be in the eLibrary) which outlines the saline attack modes on reinforced concrete in hot regions. Submerged, tidal and splash zones all have different behaviour depending on the climate and particularly rainfall. I recall reading that reinforcement is sometimmes non- preferred and a massive will last longer. We do not know what life your stucture is hoping for.

I do not see that you have considered steel piles with a generous corrosion allownce: why not?

With a refusal depth in a shoaled coastline you should have adequate supportive length to disregard seismic loads if you use independent steel spans.

Do not plan for road service to an offshore installation. Rigs use crane barges and so should you: its the sea for goodness sake. Presumably there are 2 conveyors to provide a continuity of supply if one goes down. Well done there. ■

Check the Bulk Sugar Terminal at Lucinda, Queensland, Australia. It is 5.3 Km over sea and is a concrete floor, full aluminium sheet covering steel modules at 20 metre pile spacing. It was built in 1976 and apart from severe cyclone 'YASI' damage in February this year, has performed re-markedly well and it is a reversing conveyor that I set the conveyor structure and commissioned in 1978. This is the first year that it has not loaded shipping due to damage. It also has a single vehicle travel roadway along the side on stressed concrete beams. It would be worth looking at and sea creatures do not have a chance to enter the structure. ■