DESIGN OF COMPOSITE GIRDER STRUCTURE BRIDGE OF SELUANG-1 RIVER PT LIFERE

The bridge at the Seluang-1 river is located around the palm oil plantation land owned by PT Lifere Agro Kapuas, Kapuas Regency, Central Kalimantan. In this Seluang-1 river, a bridge is planned to be built to facilitate the mobilization of palm oil plantation crops and other matters as well as transportation in the PT Lifere Agro Kapuas area because before there was a bridge the transportation traffic was cut off by the river so it had to circle quite a long way. The bridge is designed as a bridge with composite girder structure type. The methodology in the design of loading uses the SNI 1725-2016 concerning on the Loading Standards for Bridges and SNI 2833-2016 concerning on the Earthquake Resilience Planning Standards for Bridges. For methodology in designing concrete structures refer to SNI 2847-2013 concerning Structural Concrete Requirements for Buildings and methodology in designing steel structures refers to SNI 1729-2015 concerning Specifications for Structural Steel Buildings. The material used for abutment uses reinforced concrete material. The methodology in calculating the bearing capacity of the foundation uses the method by Mayerhof and also the method by Kazuto Nakazawa, while the methodology in calculating the lateral bearing capacity uses the Broms method, with the efficiency of the pile using a graph by O’Neill. From the results of topographic measurements taken a bridge design with a span of 30 m with a total bridge width of 7 m. The slab design is 25 cm thick with the compressive strenght of concrete is fc’ 30 MPa (K-350). The steel girder beam used WF Profile 1350.800.100.130 and the diaphragm beam used WF Profile 250.125.6.9 with BJ55 steel quality (fy 410 MPa). Whereas in the lower structure, the abutment designed with a height of 350 cm, a width of 320 cm and a length of 850 cm, was used with compressive strenght of concrete is fc’ 30 MPa (K-350). In the foundation used Spun Pile type piles with a diameter of 60 cm with a depth of 30 m piling as much as 8 piles on one abutment. Obtained Qallow = 116,37 tons > Qload = 114,69 tons so that the foundation is declared safe. The planned budget for the construction of a bridge on the Seluang-1 river is Rp 8.990.566.000,00.


Background
Today, infrastructure in the field of transportation is important for human life in undergoing its activities, including industry. Supporting infrastructure results in increased time efficiency in production. On the road in the palm oil plantation land owned by PT Lifere Agro Kapuas, Kapuas Regency, Central Kalimantan Province, it is felt that it is not efficient in transporting harvested products from oil palm plantations to harvest processing plants and transportation in the area due to having to circle the road far enough due to the interruption of the roads by the river. One of them is in a location named Seluang-1. At this

Design Benefits
The benefit of this thesis is to get the superstructures and substructures design of the Seluang-1 bridge location at PT Lifere Agro Kapuas that meets technical requirements but remains efficient so that it can later be utilized to facilitate the mobilization of crops and so on.

Bridge Design Criteria
In designing a bridge, the analysis carried out is as follows: a. Calculation of bridge loading.
b. Calculation of superstructures of the bridge in the form of a vehicle floor, girder and diaphragm.
c. Calculation of substructures of the bridge covering abutments, pillars and foundations.

Location Data
The design was carried out at PT Lifere Agro Kapuas, Seluang-1 location,

Bridge Loading
The load on the bridge that was designed uses the SNI 1725-2016 concerning Loading for the Bridge and SNI 2833-2016 concerning Earthquake Resilience Planning Standards for the Bridge. The type of load is divided into two types namely fixed / permanent loads and transient loads.

Vehicle Floor Slab
The vehicle floor is in the form of reinforced concrete slabs and is designed with reference to SNI 2847-2013 Structural concrete requirements for buildings.

Bridge Main Girder
The main girder in the form of steel profiles along with other steel components such as bolt connections and shear connectors are designed using the LRFD method with reference to SNI 1729-2015 Specifications for Structural Steel Buildings.

Bridge Substructure
The substructuresof the bridge consists of the design of the bridge abutment and foundation. Calculation of bearing capacity of the pile foundation using the method by Mayerhof and also the method by Kazuto Nakazawa. Then, for the calculation of the lateral bearing capacity of the pile foundation using the method by Broms.
Meanwhile, for the efficiency of the pole using a graph by O'Neill.

Cost Budget Plan
From the design drawings, it can be calculated the volume of each bridge material which is grouped into several divisions according to the type of work in accordance with Bina Marga standards.

Design Methodology
The method in design is illustrated in the flow chart.

Backrest Pipe Design
From the results of the design, the backrest pipe -thickness = 2,4 mm is used and controls the material stress ( ) ≤ allowable stress ( ): … OK

Backrest Beam Design
From the results of the design, the backrest beam WF 100.100.
From the calculation results of loading on the bridge girder obtained from the combination of Kuat 1, the ultimate moment is 15.447,29 kN.m and the ultimate shear is 1.927,77 kN.

Check assumed profile
Check back on profile:

Check the Stress Occurred at the Girder
Check the girder stresses before and after the composites: a. Stress that occurs in the main girder before the composite

Bolt Connection of Main Girder to Diaphragm Beam
From the calculation results installed 2 1/2" bolts arranged in 2 rows to 1 piece per row on the body joint plates with dimensions per side (100 × 50 × 6) mm or the total dimensions (100 × 100 × 6) mm.

Bridge Substructure Design
The design of substructure of the bridge consists of calculating the forces acting on the pile, calculating the axial and lateral bearing capacity, calculating the efficiency of the pile and pile settlement.

Foundation Design
The type of foundation used is Spun Pile Class C with a diameter of 60 cm

.4 Pole Group Efficiency from the Pole Group Test Model in Granular Soil
Then the effective carrying capacity of a single pole is obtained with Eg =  GeoSlope/W obtained SF Slope = 8,144 > SF Allow = 1,5.

Cost Budget Plan
From the design drawings, it can be calculated the volume of each bridge material which is grouped into several divisions according to the type of work in accordance with Bina Marga standards. From the calculation results, the cost budget plan for the construction of the bridge on the Seluang River-1 is Rp 8.990.566.000,00.-

Conclusion
Based on the results of the design it can be concluded that: The value is greater than the required SF value of 1,5.
3. The design plan is attached in the appendix.

Suggestion
Soil investigations should be carried out by taking more undisturbed soil samples to obtain more complete and more accurate laboratory test data.