How To Construct Precast Concrete Drop Kerb

That’s not difficult to construct these kerb, since the drop kerb is a precast product and it saves a lot of time instead of casting it on the site. Most of the contractors use precast product instead of casting it on the site, because it’s not only saving cost and also times.

1) Earthwork
You have to make sure that the condition of soil is strong enough to support the works on the ground. Otherwise, you can do a soil investigation to test the condition of soil. After that, fill about 200mm thick sub-base.

2) Concrete Base
After the earthwork is done, construct a concrete base to support the drop kerb. Mass concrete can be used to construct the concrete base since the load of the drop kerb is small. The concrete base is a cast-in-situ concrete. The insitu concrete surfaces below ground level shall be coated with road oil to avoid the water flow into the concrete.

3) Drop Kerb
Lay the drop kerb on the concrete base. The drop kerb base have to haunch with Bituminous Double Coat Paint before lay on the concrete base.

4) Pavement & Road Work
After the drop kerb is done, other works like pavement works and road works to be constructed. Pavement works consist of lower roadbase, upper roadbase and wearing course. While road works consist of 200 x 100 x 60mm grey paving blocks in Herringbone Pattern.

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Type Of Standard Kerb

1) Standard Kerb (Pedestrian Crossing)
Pedestrian crossing kerb will be used when there is a drop occurred on the roadside for Pedestrian Crossing or we called it Zebra Crossing. The depth between the kerb and finished road level is about 25mm thick only, the kerb will be slowly slim down and end up the depth is same with the finished road level. The 250×125 half battered kerb will be used in this situation. It’s a type of dropped curb that used on the pedestrian crossing.

2) Standard Upstand Kerb
Standard Upstand Kerb is a normal type of concrete curb that used on roadside. When there is a Pedestrian Crossing, Standard Upstand Kerb will be joined with the Standard Kerb (Pedestrian Crossing) as what I mentioned above. 250 x 125 Half Battered Kerb will be used. The depth between concrete curb and finished road level is about 150mm thick.

3) Standard Kerb Laid Flat
Standard Kerb Laid Flat is a very wide but thin concrete curb. The depth between concrete curb and finished road level is about 25mm thick only. Same as Standard Kerb (Pedestrian Crossing) and Standard Upstand Kerb, 250 x 125 Half Battered Kerb is used too.

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The bridge design must be prepared by expert engineer and assisted by consultant. The bridge design must be able to carry all the work load or vehicle load, or else it might be collapsed. There was many cases of concrete bride collapsed due to design fault or usage of unknown materials, which is not only happened in my country but many other countries.

Concrete bridge can be constructed by using prestressed concrete, either pre-tension method or post-tension method. Pre-tension method means the tendon has been stressed and plug in into the concrete bridge before doing concreting. Post-tension method means the tendon is stressed by the machine after it has been concreting in the concrete bridge. Prestressed concrete are very famous and mostly been used in bridge construction, the purpose of using prestressed concrete is to increase the strength of the tendon or reinforcement bar, so that it can carry and support the load on the concrete bridge.

How To Build A Bridge?

I’ll be roughly explaining on how to build a bridge. There will be 5 simple sketches about how to build a bridge. I get the sketches from my current tender in Bahrain. So, this will be the procedure of constructing a concrete bridge in Bahrain. The procedures are almost the same with my country, I think it’s the standard method and procedure of constructing concrete bridge for all the countries.

1) The bored piles for the abutments are installed. The bored piles are drilled into the soil, bored piles are used because of the status of the soil is not stable, so bored piles are used to strengthening the soil. It’s one type of ground treatment.

2) The abutments and wingwalls are constructed.

3) Bearings installed. Bearings are used to reduce the vibration when vehicle drive through the concrete bridge so that the concrete will not crack.

4) Submerged drainage pipes are installed as a drainage system to allow the rain water flows. After that, the channel below the bridge is filled with sand.

5) Superstructure is cast and prestressed sand removed. The superstructure also known as concrete beam. There is a few types of concrete beam like : U-Beam, T-Beam, cast-in-situ beam and also precast beam.

After that, all the necessary works like deck slab, pavement works, road works, parapet, railing and drainage works will be constructed. All the materials must be tested before it’s used to construct the concrete bridge so that the bridge contractor can construct a perfect and high quality concrete bridge. Cost saving is very important in construction but safety is the most important in construction as well.

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Normally concrete curb is used on housing yard or garden, it’s used to decorate our garden or yard. Most probably it’s covering the grass or tree to make it neat, clean and decorative. Few days ago, I saw this when I travel to somewhere, I saw the concrete curb was covering a type of red paver block.

As you see on the photo above, the concrete curb is surrounding the red paver block. There is few simple types of paver block such as interlocking paver, landscape paver and etc. Normally paver block is made from cement, concrete and aggregate. Many people likes to use paver block instead of laying concrete slab because it’s look unique and beautiful, house owner likes to use paver block to decorate their external floor as well. Manufacturer mix it with a few different of colour to make the pavers the look of natural stone, like granite or slate.

Red Paver Block – Made from cement, concrete and aggregate.

This type of concrete curb that surround red paver block is commonly used on the place where people want to make the place look nicer. Normally it’s used on walkway and people might walk on it. This kind of concrete curb with paver block, you can simply get some concrete contractors to construct it, it’s a very small job and most of the concrete contractors can done it well. The mixture of materials and colour must be correct so that the place can be look beautiful and great!

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Concrete road curb is the road edging where a flat pavement or path meets an unflat street or walkway, the level of both roads is different and the water will flow to the lower level portion.

It’s one type of concrete curb called combined curb and gutters. It’s commonly used to overcome the flooding problems.

Normally road curb is made from concrete, stones, alphalt and etc, but concrete and alphalt are commonly used for road curb in construction industries. Wherever you go on the road, you can see the concrete road curb besides the walkway.

Photos Of Concrete Curb At Site

Below is some photos that I took while I went to site. This is a very simple concrete curb.

- Straight Concrete Road Curb -

- Curved Combined Concrete Road Curb And Gutter -
[It's same with straight concrete road curb but it's just constructed follow the road line]

- Direction Of Flow And Concrete Slab Cover -
[There will be a small hole that allows the water flows in into the drainage]

- Drainage System -
[The water will flows into the drainage system]

Function Of Concrete Road Curb

There is a few of function and usage for the concrete curb at the roadside. There will be a few purposes of installing concrete curb :

i) Avoid Flood
It’s works as a gutter that allows the water flow in by lower road level and flow into the drainage.

ii) Safety To Driver And Motorcyclist
If there is no concrete curb there, driver might drives onto the walkway and people on the walkway might get hurt. Other than this, if there is no concrete curb as a drainage system, there must be flood when raining, the water might stopped at the roadside without flow into the drainage in proper way. It’s very slip, when motocyle or car pass by, the tires can be slip and cause them to lose visibility and ability to brake and stop down, it may causes an accident.

Type Of Concrete Road Curb

i) Basic Curb

That’s very easy to construct basic concrete curb because you don’t have to joint it with gutter, it’s a straight concrete curb. But it’s rarely used it can’t helps to overcome the flood problems, it’s only used in minimal location.

ii) Combined Curb and Gutter

This type of concrete curb is a combination of curb and gutter, the photo above shows that the gutter is used for the water flowing into the drainage system. This is commonly used in driveways everywhere.

iii) Integral Curb

This type of concrete curb are constructed as a part of sidewalk too. As you see in the photo above, the concrete curb is joining concrete sidewalk. Normally it’s cast-in-situ, which mean the concrete curb is constructed on the spot at the site.

iv) Kassel Curb

Kassel curb is purposely constructed for the buses especially in bus stops. Normally the basic concrete curb has a lower level and it’s difficult to passenger to enter the bus which has higher steps. Kassel curb has been raised up to improve accessibility for mobility-impaired passenger.

v) Precast Curb

Of course, there are some precast concrete curb too which is produced in the factory and bring to site whenever there is an usage of relevant concrete curb. Precast concrete curb will be used if the client need a faster completion of work, of course the prices for those precast concrete curb will be slightly higher than cast-in-site curb.

Pattern Of Concrete Road Curb

There is many patterns for concrete curb, as you see in the photo above, there are angle, round, mower, multi lighted, angle lighted, walkway, parking, square, wheel block and etc. Rounded concrete curbs are most commanly used for driveways that the sidewalk has grassy setback from the street.

The photo named “Straight Concrete Road Curb” above is using a wheel block concrete curb, while this pattern are commonly used for the sidewalk that lay with premix.

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