Investigasi Retak Dinding pada Jembatan Tipe Post Tensioned Prestressed Concrete Segmental Box Girder di Indonesia

Irawan, Andi Candra (2026) Investigasi Retak Dinding pada Jembatan Tipe Post Tensioned Prestressed Concrete Segmental Box Girder di Indonesia. Masters thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Post-tensioned prestressed concrete segmental box girder banyak digunakan pada jembatan bentang panjang karena efisiensi struktural dan kemudahan konstruksinya. Namun, keretakan pada dinding (web) dapat menurunkan kinerja, durabilitas, dan keandalan struktur. Penelitian ini bertujuan mengidentifikasi karakteristik retak, mengevaluasi mutu material eksisting, menganalisis respons dan kapasitas geser struktur, serta menentukan faktor dominan penyebab keretakan. Metode penelitian meliputi inspeksi visual dan pemetaan retak, pengujian non-destruktif menggunakan rebound hammer, Ultrasonic Pulse Velocity, dan bar locator, pengujian destruktif melalui core drill dan uji tarik baja, serta pemodelan elemen hingga (finite element modeling). Model dievaluasi pada kondisi layan dan ultimit dengan mempertimbangkan mutu material aktual, gaya prategang, kehilangan gaya prategang akibat creep dan susut, serta tegangan tambahan pada zona pengangkeran tendon. Hasil penelitian menunjukkan bahwa retak didominasi oleh pola diagonal (flexure-shear cracking) dengan orientasi 30°–45° pada daerah sekitar blok angkur deviasi tendon. Pola retak tersebut menunjukkan kegagalan yang dipicu oleh kombinasi tegangan geser dan tegangan tarik utama yang melampaui kuat tarik beton, sehingga retak berkembang mengikuti arah tegangan tarik utama pada dinding (web) box girder. Kuat tekan karakteristik beton aktual sebesar 31,97 MPa lebih rendah dibandingkan mutu rencana 41,50 MPa, sedangkan tegangan tarik utama kritis mencapai 2,45 MPa, melampaui kuat tarik beton sebesar 1,86 MPa. Evaluasi menunjukkan beberapa lokasi mengalami defisit kapasitas geser, sementara pengaruh creep dan susut menurunkan angka keamanan sekitar 10–15%. Keretakan disimpulkan terjadi akibat interaksi antara defisit kapasitas geser, tambahan tegangan pada daerah D-Region akibat pengangkeran tendon, kehilangan gaya prategang, serta penurunan mutu beton eksisting yang secara bersama-sama memicu terbentuknya retak diagonal pada dinding (web) box girder.
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Post-tensioned prestressed concrete segmental box girders are widely used for longspan bridges due to their structural efficiency and ease of construction. However, web cracking may reduce structural performance, durability, and reliability. This study aims to identify the characteristics of web cracking, evaluate the in-situ material properties, analyze the structural response and shear capacity, and determine the dominant causes of cracking. The research included visual inspection and crack mapping, non-destructive testing using the rebound hammer, Ultrasonic Pulse Velocity (UPV), and bar locator, destructive testing through concrete core drilling and reinforcing steel tensile tests, and finite element modeling (FEM). The numerical model was evaluated under serviceability and ultimate limit states considering the actual material properties, prestressing force, prestress losses due to creep and shrinkage, and additional stresses from tendon anchorage. The results show that cracking is dominated by diagonal flexure-shear cracks with an inclination of 30°–45° around the tendon deviation anchorage blocks. This pattern indicates that combined shear and principal tensile stresses exceeded the tensile capacity of the concrete web. The measured characteristic compressive strength was 31.97 MPa, lower than the design strength of 41.50 MPa, while the critical principal tensile stress reached 2.45 MPa, exceeding the concrete tensile strength of 1.86 MPa. Several critical locations exhibited insufficient shear capacity, whereas creep and shrinkage reduced the structural safety margin by approximately 10–15%. It is concluded that web cracking resulted from the combined effects of shear deficiency, tendon anchorage-induced stresses in the D-region, prestress losses, and the deterioration of the existing concrete properties.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	segmental box girder, retak web, metode elemen hingga, kapasitas geser, rangkak dan susut, web cracking, finite element method, shear capacity, creep, and shrinkage
Subjects:	T Technology > TG Bridge engineering > TG362 Box girder bridges--Design and construction.
Divisions:	Faculty of Vocational > Civil Engineering Maintenance and Restoration of Buildings (S2)
Depositing User:	Andi Candra Irawan
Date Deposited:	03 Aug 2026 10:31
Last Modified:	03 Aug 2026 10:31
URI:	http://repository.its.ac.id/id/eprint/142339

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