Electronic Theses and Dissertation

Abstrak
Beton merupakan material utama pada konstruksi sipil yang memiliki kuat tekan
tinggi, namun relatif lemah terhadap tarik sehingga mudah mengalami retak saat
bekerja menahan momen lentur. Penelitian ini menganalisis pengaruh perkuatan
eksternal AbFRP (serat abaka) terhadap perilaku lentur balok beton bertulang
melalui variasi bentuk lekatan, yaitu strip dan U-wrap, serta membandingkannya
dengan balok kontrol tanpa perkuatan. Pengujian dilakukan dengan pembebanan
bertahap hingga kondisi puncak, sedangkan lendutan dipantau menggunakan
LVDT, dengan lendutan maksimum mengacu pada tengah bentang. Hasil pengujian
menunjukkan beban maksimum balok kontrol (BLK) sebesar 99,44 kN dengan
lendutan maksimum 11,03 mm, balok lekatan strip (BLS) sebesar 109,38 kN
dengan lendutan maksimum 10,15 mm, dan balok lekatan U-wrap (BLU) sebesar
121,74 kN dengan lendutan maksimum 21,50 mm. Pola retak pada seluruh benda
uji diawali retak lentur dari zona tarik bawah dan berkembang progresif ke arah
zona tekan; balok kontrol cenderung memiliki retak yang lebih cepat membesar dan
lebih terkonsentrasi, sedangkan balok BLS dan terutama BLU menunjukkan retak
yang lebih terdistribusi dan terkendali akibat kontribusi perkuatan. Secara umum,
penggunaan AbFRP meningkatkan kapasitas balok, dengan konfigurasi U-wrap
memberikan peningkatan kinerja paling menonjol.
Kata kunci: beton bertulang, serat abaka, perkuatan eksternal, kapasitas lentur, pola retak, lendutan.

Abstract Concrete is a primary material in civil construction due to its high compressive strength; however, it is relatively weak in tension, making it prone to cracking when resisting bending moments. This study analyzes the effect of external AbFRP (abaca fiber) strengthening on the flexural behavior of reinforced concrete beams by applying different bonding configurations, namely strip and U-wrap, and comparing the results with a control beam without strengthening. The test was conducted using incremental loading until reaching the peak condition, while deflection was monitored using LVDTs, with the maximum deflection referring to the mid-span displacement. The results showed that the maximum load of the control beam (BLK) was 99.44 kN with a maximum deflection of 11.03 mm, the strip-bonded beam (BLS) reached 109.38 kN with a maximum deflection of 10.15 mm, and the U-wrap bonded beam (BLU) achieved 121.74 kN with a maximum deflection of 21.50 mm. Cracking patterns in all specimens initiated as flexural cracks in the bottom tension zone and progressively propagated toward the compression zone. The control beam exhibited faster crack widening and more concentrated cracking, whereas the BLS and especially the BLU beam showed more distributed and controlled cracking due to the contribution of AbFRP strengthening. Overall, the use of AbFRP increased the beam capacity, with the Uwrap configuration providing the most significant improvement in performance. Keywords: reinforced concrete beam, abaca fiber, external strengthening, flexural capacity, crack pattern, deflection.