The 6th International Conference of Asian Concrete Federation
21-24 September, 2014, Seoul, Korea
CONSTRUCTION OF REINFORCED CONCRETE TRUE ARCH BRIDGE BEAMS YEH PENET RIVER, BALI
I N Sutarja† and I M A K Salain††
† Civil Engineering Magister Program, Udayana University, Bali, Indonesia E-mail: [email protected]
Abstract
Yeh Penet River Bridge at Sangeh Village, Badung regency, Bali Province was built to connect the tourism areas of Tabanan and those of Badung regency in the north of Bali. The total length of the bridge is 120,000 mm, consisting of: 1) main span in the middle along the 80,000 mm, reinforced concrete true arch beams, 2) additional span at the beginning and end of the bridge, prestressed concrete beams with a length of 20,000 mm, respectively.
The dimension of the base of the true arch beam is 1000/3500 mm, and the top of the true arch is 1000/2000 mm, designed in accordance with the Indonesian National Standards for bridges, namely Bridge Management System (1992). The analysis shows that the dominant arch compressive stress occurred, the minimum reinforcement (1%), except at the height of true arch reinforcement reaches 2%.
The implementation of true arch beams casting was done gradually by 2000 mm long using Traveler. The construction of this bridge took 2 years, because of the difficult terrain. In 2013, this bridge was completed and has been functioning properly in accordance with the plan.
Keywords: reinforced concrete, true arch, bridge.
1. INTRODUCTION
The rapid development of infrastructure to support tourism in Bali can bring a positive impact such as increasing regional revenues, job opportunities, and increasing people’s welfare.
The development of tourism sector can also encourage local government to provide better infrastructure, such as roads and bridges, water supply, electricity, telecommunications, public transportation and other facilities.
Foreign tourist arrivals to Bali in 2013 reached 3.2 million people, or more than that in 2012 which was as many as 2.8 million people.
There were several factors that caused an increase in foreign tourist arrivals in 2013, among other things was infrastructure development of roads and bridges, which in various locations began to be completed so that traffic jam was reduced [1, 3].
The infrastructure developments in Bali are not balanced between the northern and southern
parts of Bali. Various infrastructures built presently tend to be focused on in the south of Bali. Stacking development in the southern parts of Bali was mainly in the form of hotel infrastructure, roads and bridges, and other travel accommodations while in the north and east of Bali such as in Buleleng and Karangasem, the development is still not evenly distributed including in Jembrana, west of Bali. The entire Bali area, both in the northern and southern parts of Bali is very beautiful and is very potential. It needs government policy to direct development to the north. The main thing that must be addressed in the north is a public infrastructure, including access roads and bridges.
Yeh Penet River Bridge is located in the Village of Sangeh Badung, Bali Province. It is planned to connect the tourism areas of Tabanan and those of Badung regency in the north. This bridge will be the closest alternative path connecting Alas Kedaton tourism area and
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Bedugul in the northern part of Tabanan with Sangeh and Plaga as a tourism area in the northern part of the Badung regency. By the opening of new access in this area, it is expected to increase all life aspects of the community of the surrounding areas, especially economic aspects [5].
2. PLANNING AND IMPLEMENTATION 2.1 Planning
With the considerations based on 1) the location of the bridge geometry conditions with river width of 120,000 mm and a depth of 79,000 mm; 2) basic soil conditions; 3) functional requirements; 4) aesthetics; 5) economy and ease of maintenance; 6) construction and implementation considerations;
and 7) the applicable laws, then the main structure chosen is the reinforced concrete arch beam model, namely True Arch bridge which arch beam is under the vehicle floor [4, 5].
Fig. 1 Top and front views of the bridge The main structure is in the form of 3 beams of reinforced concrete true arch (Fig. 1), with the dimension on the base of the arch beam is 1000/3500 mm and at the peak is 1000/2000 mm. The bridge length is 120,000 mm (20,000 mm girder beam + 80,000 mm arch beam + 20,000 mm girder beam) and the width of the bridge: 7000 mm vehicle floor and 2 x 1000 mm trotoir.
Fig. 2 Model analysis and design
The result of the analysis shows that the dominant arch compressive stress occurred, as well as the minimum reinforcement is obtained (1 %, except at the height of arch 2 %). This shows that the selection of a reinforced concrete true arch beam structure as the main structure is very good regarding that concrete is stronger in accepting a compressive force than tensile force.
Structure system of the reinforced concrete true arch beams designed has satisfied the technical requirements such as strength and rigidity to support loads determined by the applicable regulations.
2.2 Implementation
The structure consists of three true arch beams whose length is 80,000 mm. The construction process could not be done by using conventional scaffolding because the bridge was built above a steep and deep river. Therefore, cantilever system construction method was used with the help of tie rod and the work was done from each side segmentally and met in the middle of the span.
This method uses a system of cast in-situ casting, thus, the casting implementation of each true arch beam segment requires auxiliary tools.
That tool is called a traveler, a tool which is used to support formwork for casting the arch beam.
The construction formwork is a temporary helper which is a mold on the side and bottom of a concrete construction desired. Traveler formwork means moving formwork which is functioned repeatedly in a segmental work, functioned as a hanger or supporting formwork and formwork mover for casting next segment [2].
In Fig. 3, it can be seen that the traveler formwork, which was used for this work, is a traveler system with manual movement and the casting length in each segment is 2 meters.
Fig. 3 Beams arch construction with traveler and temporary cables stayed
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The process of implementation of the segmental true arch beams also used temporary cables stayed supported by pylons and centric prestressing steel 4 x 12 x 7 wires at each edge of the arch beams (Fig. 4). These cables stayed and prestressing steel were used to reduce the tensile stresses in the arch beam concrete. The concrete stress was all in compression i.e. 2.50 MPa on the upper fiber and 5.97 MPa at the bottom fiber.
Fig. 4 Cables stayed supported by pylon during construction
After casting the beam segment of the last true arch in the middle span was complete, then it was continued with the column and vehicle floor construction, so as to create a True Arch Bridge, as shown in Fig. 5.
Fig. 5 Column and floor vehicle construction
2.3 Discussion
The structural geometry of the reinforced concrete true arch bridge is very good; because in the dominant true arch, minimum reinforcement and compressive stress occurred.
This is very advantageous because concrete is very strong in receiving compressive force.
System structure of reinforced concrete true arch beams that has been designed and implemented by the method of cantilever traveler meets the technical requirements i.e. the requirements of strength and rigidity to support loads in accordance with applicable regulations.
The architecture true arch of bridge in the form of beams can provide aesthetic value beside as a transport infrastructure, because the Yeh Penet River Bridge looks aesthetic from the tourist sites of Tanah Uwuk, Sangeh, as shown in Fig. 6.
Fig. 6 Esthetic view of the Yeh Penet River Bridge from Tanah Uwuk
3. CONCLUSION
The study of planning and construction method of Yeh Penet River Bridge, located in Sangeh, Bali Province, Indonesia, using true arch beam structural system reinforced concrete shows that this bridge has fulfilled the technical and aesthetic requirements and has been functioning properly.
REFERENCES
[1] Anonim, 2014a,http://skalanews.com/
berita/detail/165703/Peningkatan-Wisman- ke-Bali-2013-Tertinggi
[2] Anonim, 2014b, Republik Teknik Sipil, Anonim, 2014, Republik Teknik Sipil, http://www-tekniksipil.blogspot.com
/2012/01/form-traveller-pada-proyek- jembatan.html
[3] Agung, G., 2013, Peningkatan Wisman ke Bali 2013 Tertinggi,
[4] Melbourne, C., 1995, Arch bridges, Proceedings of the First International Conference on Arch Bridges held at Bolton, UK on 3-6 September 1995, London, Thomas Telford.
2.50
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5.97
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[5] Sutarja, I.N., 2007., Perencanaan Jembatan Balok Pelengkung Beton Bertulang Tukad Yeh Penet, Di Sangeh., Prosiding Konferensi Nasional Teknik Sipil I, Universitas Atma Jaya, Yogyakarta 11-12 Mei., ISBN-979.9243.80.7., hal. 419-425.
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