ANALYSIS METHOD OF GRADUAL CAST INSITU PROJECT COMPLETION OVERPASS PT. TALENTA

Overpass project development Marabahan is a CSR (Corporate Social Responsibility) from PT. Talenta Bumi, namely making public care facilities for the security and facilitate road transport and to improve the welfare of society .This project Overpass consists of main bridge prestressed concrete girders with spans of 30 m and bridges using slab pile construction with a total length of 200 m. This study aims to determine the calculation method of the analysis of in situ casts gradually and to determine the method of implementation of the phasedsitu cast on Marabahan Overpass project. Analysis of cast insitu method stages in the project completion Overpass PT. Marabahan Earth's talents will be obtained security calculations on the structure of the Overpass. Foundry work first is casting with cast in situ on the crown, after it's done casting method cast in situ stages at the slab to be divided into two stages, namely the first layer 20 cm (half slab) and the second layer 15 cm (top slab) using scaffolding as a scaffold and job formwork with main reinforcement ɸut 22-150 which gradually cast directly on the ground with the popularity chart Fc validation test cylinder '30 MPa and graphs coefficient of concrete strength PBI age 71. For loading on board, the work scaffolding (scaffolding) at the time of cast insitu gradually in the field wearing a scaffold with a heavy load capacity (heavy duty) has a maximum load of 675 kg/bay or 0.675 tons/m 2 , and using strong wooden scaffolding with wood class III based voltage PKKI 1961 timber permit. Based on the analysis results of calculations using the method of cast insitu gradually, by doing a test trial error with conditional on calculation of security moment of the plan should be greater than the moment of ultimate, then casting the first layer half slab in getting workable with the concrete less than one day the Fc '5 MPa and to stage a second layer using a comparison chart coefficient PBI age compressive strength, obtained Fc' 9.57 MPa to 1.5 days workmanship of the concrete casting. With the trial based on the test results of the concrete age, can accelerate and cut time jobs and can save the cost of the work, such as the cost of the use of formwork and scaffolding usage. suggestednecessary to test the concrete test cylinders for 1 day, 2 days, 3 days, etc,so that getting the maximum test.


CERUCUK
The bridge is a construction that is part of the way that is needed in the road network that will support the development of an area.
Marabahan overpass bridge construction project is a CSR program (Corporate Social Responsibility) from PT. Talents Earth Marabahan, namely making public care facilities for the security and facilitate road transport and to improve the welfare of the surrounding community. The overpass project consists of: This overpass job takes 300 calendar days for Rp 36,442,500,000.00 (Thirty-Six Billion Four Hundred Forty-Two Million Five Hundred Thousand).
This development is a Local Public Infrastructure Improvement of CPS program PT. Talents Earth. The construction contractor is PT. Asphalt Concrete Batulicin and consultant supervisor is CV Fourteen.

LITERATURE REVIEW Cast Insitu Gradually
Casting is the process of mixing the ingredients -the basic ingredient of concrete, namely cement, water, sand, and gravel into the mold a structure element that has been fitted with steel reinforcement.
In Civil Engineering, gradually cast types are of two kinds, namely concrete that has been printed in the plant (pre-cast) and concrete cast on site (in-situ).
Cast insitu gradualfoundry cast concrete directly performed on the location of structural elements that have been planned to be gradual. In high-rise buildings or a bridge overpass this Marabahan, for example the floor which is exceptionally spacious and workmanship are very high elevation makes it impossible to carry out casting an entire floor in one of workmanship.

Age Concrete
For determining the quality of the concrete compressive strength may be tested within 28 days. In-PBI has mentioned that there is a factor of the concrete to test the age of 28 days. As these factors are at 3 days of age 7 days 0,46 14 days 0.88 and 0.7 at 28 days can be seen in the form of the following Plate is a structural element that is often used in a variety of bridge or overpass. Plates on a bridge or overpass has the function, among others separation between the basement and a room on the bridge, where diletakannya electrical wiring and lighting in the basement, muffle noise (noise) from the upper room or basement, adding stiffness horizontally on the building and as the basis of vehicle passing.
Plates without thickening: 125 mm while the plate thickening: 100 mm. tp = Minimum thickness of the slab without beams can be seen in the table below: Volume 5 No. 2 2021 (105-120) 108 Plates floor or slab is thin field elements that bear the burden of the transversal (latitude) through the action of the bending force distributed on each pedestal of the plate. Some types of floor slabs which are widely used in the construction of which is a: a.

Flat Slab System
Flat Slab system is reinforced concrete slab, which is directly supported by the columns without beams. b.

Grid Flooring Systems
The grid floor system (Waffle system) has beams that intersect each other at a distance that is relatively dense, with a thin top plate

Scaffolding
Scaffolding is a temporary work platform or as a temporary structure used to support people and material in the construction or repair of buildings and other large buildings. The usefulness of the scaffold is as a safe haven for workers or workers to work at high altitudes so that the safety of the workers or artisans assured. And benefit from the use of this scaffolding is the cost savings and efficiency scaffolding installation time.
And for the classification of the capacity or ability of the scaffold there are no 3, namely:

1.
Light weights (light duty) to have the burden of 225 kg/bay.

2.
Charges are being (medium duty) has a maximum load with a weight of 450 kg/bay.

Scaffolding Wood
Although somewhat outdated, but the type of wood scaffolding can still be found in use. For scaffolding of wood usually used timber with a diameter of 5-10 cm, 6-12 cm long, and 8-12 cm.

RESULTS AND DISCUSSION
Overpass condition and the material used in the design is known as follows:

Stages cast insitu method of gradual implementation in Marabahan City
Overpass construction project on the floor plate (slab), namely: 1.
On Overpass project has advantages in terms of design in the reinforcement that has a large diameter that is d22-150, and have Fc' of 30 MPa, and the quality fy = 400 MPa and done with segmental is divided into two stages of casting. 2.
The first to do is reinforcing work, which assembles iron-steel reinforcement.

4.
After the formwork has been prepared, and the irons that have been assembled was placed into the formwork has been made by with the initial design in this formwork work using scaffolding ½ frame.

5.
Before the foundry work performed checks on the power of the formwork, after checking his strength, then proceed to do the job pegecoran with the cast in situ on the crown.

6.
After that, then do casting on a slab. At the foundry casting is done for firsttier stage (half slab), which is done with the casting use 20 cm thick, using a formwork with reinforcement d22-150 mm in the cast in the field.

7.
Then the next stage is done for the casting of the second layer (top slab) together with the first layer, but with some additions to determine the loadload, top slab with a thickness of 15 cm 8. Then made by calculating your weight due to load half slab, coupled with his heavy burden on the top slab.

9.
After that, compared with the value of Mr and Mu, if Mr > Mu then cast stop work (completed).

Reinforcement Calculation On Crown (v shell)
Calculations To work on the crown can q conversion = 0.49896 t/m, which has the burden is smaller than the heavy load of scaffolding used is ½ frame = 0.625 t / m²> 0,462 tonnes / m² (Secure). Long slab = 10.5 m and a width of reviews long slab = 4.6 m -For the calculation of its own weight in half slab floor plate2.4 tonnes / m3 x 0.20 m = 0.48 ton / m2 which has a smaller load than a heavy load of scaffolding used is ½ frame = 0.625 tons / m2> 0.48 ton / m2 (Secure).
-Based on the calculation of casting for the second phase (top slab) does not require scaffolding again, because in casting the first phase (half slab) can be said to have been strong to bear the burden themselves, and in other words, may help substitute as scaffolding (scaffolding).

CONCLUSION
Conclusions from the analysis of foundry work stages using cast in-situ stages after of the project Overpass cities Marabahan on roads Marabahan -Margasari South Kalimantan is that by using cast in-situ stages can speed up or cut back on jobs and save costs, for example the use of formwork and scaffolding usage fee. To cast insitu casting stages in the first tier (half slab) is less than one day been able to carry his weight with the added help of scaffolding to carry the weight, and for casting the second layer (top slab) can be done on the day of its day. But in the field of workers usually takes 1-2 days to work formwork and reinforcement installation.

Suggestion
To get the maximum test test test needs to be done to the concrete cylinder 1 day, 2 days, 3 days, and so on. Test cylinders conducted to validate the coefficients used in the calculation method of cast insitu gradually, and addition also it is necessary to the application of occupational safety, and health K3 must be done and done, the work of construction of the bridge Overpass with the process is carried out at an altitude high enough, if not carried out and implemented correctly as well as good supervision, it is feared could lead to accidents.