PERENCANAAN ALTERNATIF TENDON PRATEGANG DENGAN VARIASI TATA LETAK TENDON DAN MUTU TENDON PADA STRUKTUR ATAS JEMBATAN BATANG LASI KOTA SAWAHLUNTO - Digo, Muhammad; Juliafad, Eka (Teknik Sipil Universitas Negeri Padang, 2023)
Abstrak: Jembatan Batang Lasi dibangun dengan menggunakan beton prategang PCI girder dengan beton mutu fc 45 mPa dan menggunakan tendon dengan mutu ASTM A416 grade 270 low relaxation. Dalam perencanaan beton prategang, mutu dan layout tendon berpengaruh dalam menghasilkan tegangan-tegangan, serta loss of prestressed. Untuk itu perlu alternatif perencanaan layout tendon dan mutu yang berbeda, untuk mengetahui pengaruhnya terhadap elemen prategang untuk jrmbatan. Penelitian ini bertujuan untuk mengetahui kemampuan PCI girder dalam memikul gaya gaya yang bekerja serta melakukan analisa kehilangan gaya prategang akibat pengaruh penggunaan mutu dan letak tendon prategang. Jenis penelitian yang digunakan pada tugas akhir ini adalah penelitian kuantitaif dengan menggunakan metode analitis yang mengacu pada SNI 2847-2013. Hasil dari penelitian ini yaitu terdapat perbedaan tata letak tendon strand 7 wire ASTM A416 grade 250 low relaxation dan strand 7 wire ASTM A779 grade 270, dengan tendon yang digunakan di jembatan Batang Lasi. Kehilangan gaya prategang yang terjadi pada tendon 12,7 mm (strand 7 wire ASTM A416 grade 250 low relaxation) diperoleh nilai terkecil pada loss of prestressed akibat gesekan angkur, pemendekan elastis, relakasasi tendon, dan gaya prategang efektif. Sementara kehilangan gaya prategang akibat gesekan tendon dan pengangkuran diperoleh nilai terkecil dengan menggunakan tendon di lapangan (strand 7 wire ASTM A416 grade 270 low relaxation). Dari hasil analisis kedua variasi mutu tendon diketahui bahwa hanya strand 7 wire ASTM A416 grade 250 low relaxation yang mampu memikul beban dan memiliki loss of prestressed yang kecil daripada yang digunakan di strand 7 wire ASTM A779 grade 270 Kata Kunci: Loss of prestrssed, tendon prategang, tata letak tendon, mutu tendon, posisi tendon, tegangan, balok prategang, girder. Abstract: The Batang Lasi Bridge was built using PCI girder prestressed concrete with fc 45 mPa quality and using ASTM A416 grade 270 low relaxation tendons. In the design of prestressed concrete, the quality and layout of the tendons are influential in producing stresses, as well as loss of prestressed. For this reason, it is necessary to plan alternative tendon layouts and different qualities, to determine the effect on prestress elements for bridges. This study aims to determine the ability of the PCI girder to withstand the applied forces and to analyze the loss of prestressing forces due to the influence of the quality and location of the prestressed tendons. The type of research used in this final project is a quantitative research using analytical methods referring to SNI 2847-2013. The results of this study are that there are differences in the layout of ASTM A416 grade 250 low relaxation 7 wire strand tendons and ASTM A779 grade 270 7 wire strand tendons, with the tendons used in the Batang Lasi bridge. Loss of prestressing force that occurs in the 12.7 mm tendon (strand 7 wire ASTM A416 grade 250 low relaxation) obtained the smallest value for loss of prestressed due to anchor friction, elastic shortening, tendon relaxation, and effective prestressing force. While the loss of prestress due to tendon friction and anchorage, the smallest value was obtained by using a tendon in the field (strand 7 wire ASTM A416 grade 270 low relaxation). From the results of the analysis of the two variations in tendon quality, it is known that only ASTM A416 grade 250 low relaxation strand 7 wire is capable of carrying loads and has a smaller loss of prestressed than that used in ASTM A779 grade 270 strand 7 wire. Keyword: Loss of prestressed, prestressed tendon, tendon layout, tendon quality, tendon position, stress, prestressed beam, girder.