FIELD REPORT

JUWON VENTURES LTD.

FIELD REPORT

The experience garnered within the past five months is great but to name a few, three aspects of structural engineering will be put into proper perspective as highlighted and further expatiated below!

·         Fence Installation

·         Retaining Wall

·         Gate Pillars/Mounting of Gate

*AGGREGATES

Putting this into context: The essence of Aggregates cannot be overemphasized, as it is obviously seen to be the ‘heart’ of construction either in brick-formation/brick-laying, concretes, etc. It is therefore important for a structural engineer to uphold standards in all stages of construction (In building and construction professionalism/integrity is often perceived to be at stake for the handlers)

 

Types of Aggregates

·         Coarse Aggregate

·         Fine Aggregate

Coarse Aggregate

Gravel mostly constitutes the coarse aggregate and the ratio I've learned to be acceptable on sites is 1:2:4. In this numeric expression, each figure represents different materials and the number of head-pan(s) required. (See below illustration for further explanation)

                       1     :     2    :     4

         Cement        Sand     Gravel

A bag of cement contains two head-pans of the content, therefore – mixture involving one bag of cement will require four (4) head-pans of sand and eight (8) head-pans of gravel.

Fine Aggregate

Unlike coarse aggregate where gravel/crushed-stones happened to be a major component. In this case- Fine Aggregates only demands cement and sand which are often used in brick-formation/brick-laying, plastering, etc

For Brick-formation the acceptable ratio is 1:7 and 1:5 for plastering; which means for each bag of cement used, fourteen (14) head-pans of sand will be applied and ten (10) head-pans of sand for brick-formation and plastering respectively.

FENCE INSTALLATION

*Right of way should not be less than 5ft from access road, main road etc

·       

             Digging

·         Cast the base

·         Laying of bricks

·         Casting of pillars

Digging

      Ø  Width = 2ft

      Ø  Depth = 3ft

*Length is determined by the ‘intended’ distance to be secured on the piece of land.

Base

Once digging is done, the application of coarse aggregate should be necessitated to construct the base at 4inches thickness level and leave for couple days for solidification.

Brick-formation

After digging and casting the base with coarse aggregate, it is very essential to make sure the setting out of first-row-bricks on the concrete base must be accurate, this can be ensued through the use of “plumb” and making sure it is horizontally proportional with the centered line.

*In construction it is advisable to raise project a little above standard. A good structural engineer must be cognizant of “eventualities”, even if it appears impossible –s/he must consider the general assumption that the primary purpose and function of a project could be abused by clients, dwellers etc.

Therefore, the first three rows of the brick-formation should be filled with coarse aggregate, which would ensure fortification and enhance longevity.

Casting of pillars

In any project where the pedigree of the handler is at stake, it is thereby important for the engineer in charge to do the needful in ensuring a type of fence-installation that will involve the casting of “concrete pillars” in-between its formation should be encouraged.

Along the fence formation, the measurement or distance that separates each pillar from the other could vary. Measurement using the common tape could reads 7ft, 8ft or even 9ft.

The size of each pillar as regards to its width and height could be determined by different factors. Although 9inches by 9inches or 1ft by 1ft is said to be acceptable for the width while its height is determined by the ‘intended’ space to be secured.

In other to ensure convenience for the carpentry service, a lengthy space of 2ft could be reserved in-between the fence formation for the construction of woodworks and casting of pillars thereon. It is also essential to note that reinforcing bars/rebar/ironworks give efficacy to pillars, that being said- All the woodworks constructed for the casting of pillars between the fence-formation must be reinforced with ironworks before the application of coarse aggregate. The reinforcing bar must be vertically positioned and centered in each of the woodworks.

Once the pillars are cast and since solidified thereon, the opening space between each pillar and brick formation can then be merged or closed with bricks.

RETAINING WALL

Amongst many functions of retaining wall, it controls erosion especially soil erosion and prevents mud or small rivulets on a slope from pouring down.

In this situation `I mean focusing on its purpose on site’ a concrete wall is cast using coarse aggregate mainly to stop the pouring down of erosion from a sloppy topography.

·         Digging

·         Reinforcing bar (Rebar)/Ironwork

·         Cast the base

·         Bracing

·         Cast the wall

Digging

      Ø  Width = 3ft

      Ø  Depth = 3ft

*Length is determined by the intended distance to be secured on the piece of land.

Reinforcing Bar (Rebar)/Ironwork

In this type of construction, reinforcing bars are in two patterns. The positioning of the ironworks are both in horizontal and vertical forms; the concrete base will submerged the former, while the latter will be buried in the wall. Reinforcing bars are considered to be the `heart and soul’ of retaining wall, it strengthens the wall and gives it power to withstand pressure!

Cast the base

The next process will involved the application of coarse aggregate at 6inches thickness level, which will successfully engulfed the 2ft –wide rebar lying inside the pit in a horizontal position.

Bracing

There are different types of bracing designs; we have steal design, concrete design etc.

*Using concrete design –reference to field report!

A 2ft –wide plank is placed on the far edge of the concrete base and tilted toward the reinforcing bar in standing position, I mean the vertical ironwork intended to be buried inside the main wall. 

Measuring the space between the top of the *tilted plank and the standing rebar should be 3inches or thereabout and a carpentry service must be initiated to maintain the needed measurement, as well as accommodating the use of poker vibrator. 

The next process would be to apply coarse aggregate all the way from the top of the 2ft –*tilted plank down to the far corner of the base. The use of poker vibrator must be encouraged to ensure fortification and solidification

Cast the wall

In all the processes involved in constructing A Retaining Wall, it is important for the handler to uphold standards in all its stages. Expertise generally say there won't be a second chance for a structural engineer to get it right; s/he can only get it right once!

As soon as the concrete bracing solidifies, carpentry service will follow suit to prepare a mold-box/frame from the bracing all the way up until the vertical reinforcing bars are equaled and the intended height is accomplished. Thereafter, coarse aggregate could then be applied and leave for couple days to solidify.

GATE PILLARS/MOUNTING OF GATE

Literally –Gates give access to a secured piece of land.

·         Digging

·         Placement of Rebar/Reinforcing bar/Ironwork

·          Cast the base

·         Mount the gates

·         Carpentry Service

·         Cast the pillars

Digging

      

      Ø  Width = 3ft

      Ø  Depth = 3ft

After acknowledging the size and measurement of the gate intending to mount; the job of the handler is made easy by knowing the distance between both pillars and to identify the two spots where digging will commence.

Two separate spot will be dug; the digging measurements for both pits are 3ft deep and 3ft wide on four sides.

Placement of Rebar/Reinforcing bar/Ironwork

The reinforcing bars are in two forms; the horizontal rebar which is known as mat and the vertical rebar.  The mat will be buried inside the concrete base while the gate-pillars will swallow the vertical reinforcing bar.

The type of steel for the rebar will be determined by the size of the gate-pillars, the bigger the pillar the bigger the reinforcing bar. A pillar of 1ft by 1ft is welcome to use 12mm steel for both the mat and the vertical rebar.

Note

The vertical measurement of the reinforcing bar is determined by the height of the gate, which in-turn will be the height of the pillar and presumably the height of the fence.

Thereafter, the vertical rebar will be centered on the horizontal rebar (mat) with the aid of binding wire and this process must be checked with continuous use of plumb for accuracy and ensure an upright positioning.

Also the positioning of both pillars must be linear to the fence installation and this can be achieved through the conventional use of line/rope to align the vertical reinforcing bars with the fence.

Cast the base

Thereafter – both pits will be filled with coarse aggregate. This process will submerge the mat on 2ft by 2ft and a thickness level of 9inches which apparently will engulf a portion of the vertical rebar.

Mount the gates

It is not advisable to introduce the gates before the concrete-base in both pits solidifies. By extension, a day or two could be dedicated for the aggregate to bake. Thenceforth, the gates would be mounted and married together with the vertical rebar on both sides. Once the gates are accurately positioned with the aid of plumb, it can then be tightened with binding wire to steadfastly hold it together with the vertical reinforcing bars and maintain the accuracy.

  

Carpentry Service

The construction of woodwork will commence from the concrete-base: Using planks –A 1ft by 1ft vertical mold-box/four-sides frame will be fastened together and strong enough to accommodate the use of poker vibrator, therefore suspending the vertical reinforcing bar married with a portion of the gate in its middle. This should be carried out on both sides.

Cast the pillars

The next stage would be the introduction of coarse aggregate to fill up both frameworks/mold-boxes.

Note

In other to ensure the pillars are firmly baked –a poker vibrator should be introduced at every 4m of the filling process, I mean during application of coarse aggregate.