Flexural Capacity Enhancement of Timber Beams Partially Confining the Principal Compression Arch using Carbon Fiber Reinforced Polymer Composites

Author(s):  
Md. Mashfiqul Islam ◽  
Ashfia Siddique ◽  
Alireza Pourhassan ◽  
Md. Arman Chowdhury ◽  
Jarin Tasnim

Timber is widely used as a structural element because of its engineering and mechanical properties. This study focuses on the flexural behavior of timber beams externally reinforced with carbon fiber reinforced polymer (CFRP) composites at the tension face and the responses of the fundamental principal compression arch because of confinement from end anchorage. Beams of three different types of timber are studied. All the beams had the same length, width, and span length and were tested under four-point loading. Different CFRP lamination techniques were adopted, with and without U-clamp confinement as end anchorage, to investigate the flexural capacity enhancement of CFRP strips as reinforcement for timber beams. The profile of the principal compression arch is estimated experimentally from fundamental flexural strain-along-depth phenomena by post-processing high definition images extracted from test videos employing digital image correlation technique (DICT) in the MATLAB R2011a framework. Similar responses were found from finite element analysis using ANSYS 11.0. Effective confinement of the principal compression arch produced significant enhancements of flexural capacities and stiffness in the strengthened timber beams.

2019 ◽  
Vol 9 (8) ◽  
pp. 923-930
Author(s):  
Ning Zhuang ◽  
Junzhou Chen ◽  
Miao Zheng ◽  
Da Chen

Flexural capacity of RC beams gets significant improvement with externally bonded Carbon Fiber-reinforced Polymer (CFRP) sheet. The anchorage system is a valid means to restrain or delay debonding failure caused by stress concentration at the ends of CFRP sheets. In this paper, four RC beams, measuring 150 × 200 × 1900 mm, were examined under four-point bending test. One beam was applied for contrast. And other three were CFRP strengthened with no anchorage, CF anchors (carbon fiber anchors) and U-wraps (U-shaped CFRP wraps). The primary purpose of the experiment was to validate the effectiveness of CF anchors and U-wraps in improving the flexure character of beams strengthened with CFRP sheets. The experimental results revealed that the strengthened beams using anchorage systems performed remarkably in beam ductility, flexural capacity, load-deflection response and failure mode compared with the contrast beam. The anchorage systems were more effective and necessary to enhance the flexural behavior of beams as using CFRP laminates for flexural strengthening.


Author(s):  
Sri Rejeki Laku Utami

ABSTRACTThe effect of Carbon Fiber Reinforced Polymer (CFRP) on reinforced concrete beams is expected to contribute to increased ductility. In this study five beam specimens. The first test object is a 3D16 Normal beam that is used as a normal beam. The second test object is a 3D16 CFRP beam which is used as a beam with CFRP treatment. The third test object is a 4D16 Normal beam that is used as a normal beam. The fourth test object is a 4D16 CFRP beam that is used as a beam with CFRP treatment. The fifth test object is the 5D16 CFRP beam used as a beam with CFRP treatment. The dimensions of the beams are 150 x 250 mm, with an effective length of 2000 mm. Pembebanan diberikan One Point Loads, untuk melakukan uji lentur maka pembebanan pada balok direncanakan dengan menempatkan satu buah gaya P secara simetris pada jarak ½ L yaitu sebesar 1000 mm. Dan diberikan perlakuan CFRP pada balok 3D16 CFRP sepanjang 600 mm (2,4 h) ditengah bentang yang panjangnya 2.000 mm  dengan perlakuan CFRP Completely Wrapped Member. From the results of testing the maximum flexural capacity in a row for the 3D16 Normal beam is 104.04 kN while the 3D16 CFRP beam has a maximum increase in bending capacity of 119.52 kN while the 4D16 Normal beam has a maximum bending capacity of 161.28 kN while the 4D16 beam CFRP has a maximum increase in bending capacity of 162.64 kN, while the 5D16 CFRP beam has a maximum increase in flexural capacity of 173.16 kN. Keyword: CFRP (Carbon Fiber Reinforced Polymer), Flexural StrengthABSTRAKPengaruh Carbon Fiber Reinforced Polymer (CFRP) pada balok beton bertulang diharapkan memberikan konstribusi terhadap peningkatan daktilitas. Pada kajian ini lima buah benda uji balok. Benda uji pertama adalah balok 3D16 Normal yang digunakan sebagai balok normal. Benda uji ke dua adalah balok 3D16 CFRP yang digunakan sebagai balok dengan perlakuan CFRP. Benda uji ke tiga adalah balok 4D16 Normal yang digunakan sebagai balok normal. Benda uji ke empat dalah balok 4D16 CFRP yang digunakan sebagai balok dengan perlakuan CFRP. Benda uji ke lima dalah balok 5D16 CFRP yang digunakan sebagai balok dengan perlakuan CFRP. Dimensi balok – balok tersebut adalah 150 x 250 mm, dengan panjang efektif 2000 mm. Pembebanan diberikan One Point Loads, untuk melakukan uji lentur maka pembebanan pada balok direncanakan dengan menempatkan satu buah gaya P secara simetris pada jarak ½ L yaitu sebesar 1000 mm. Dan diberikan perlakuanCFRP pada balok 3D16CFRP sepanjang 600 mm (2,4 h) ditengah bentang yang panjangnya 2.000 mm  dengan perlakuan CFRPCompletely Wrapped Member. Dari hasil pengujian kapasitas lentur maksimum secara berturut- turut untuk balok 3D16 Normal sebesar 104,04 kN sedangkan pada balok 3D16 CFRP mengalami peningkatan kapasitas lentur maksimum sebesar 119,52 kN sedangkan  balok 4D16 Normal memiliki kapasitas lentur maksimum sebesar 161,28 kN sedangkan balok 4D16 CFRP mengalami peningkatan kapasitas lentur maksimum sebesar 162,64 kN, sedangkan balok 5D16 CFRP mengalami peningkatan kapasitas lentur maksimum sebesar 173,16 kN. Kata kunci: CFRP (Carbon Fiber Reinforced Polymer), Kuat Lentur


2019 ◽  
Vol 7 (1) ◽  
pp. 30-34
Author(s):  
A. Ajwad ◽  
U. Ilyas ◽  
N. Khadim ◽  
Abdullah ◽  
M.U. Rashid ◽  
...  

Carbon fiber reinforced polymer (CFRP) strips are widely used all over the globe as a repair and strengthening material for concrete elements. This paper looks at comparison of numerous methods to rehabilitate concrete beams with the use of CFRP sheet strips. This research work consists of 4 under-reinforced, properly cured RCC beams under two point loading test. One beam was loaded till failure, which was considered the control beam for comparison. Other 3 beams were load till the appearance of initial crack, which normally occurred at third-quarters of failure load and then repaired with different ratios and design of CFRP sheet strips. Afterwards, the repaired beams were loaded again till failure and the results were compared with control beam. Deflections and ultimate load were noted for all concrete beams. It was found out the use of CFRP sheet strips did increase the maximum load bearing capacity of cracked beams, although their behavior was more brittle as compared with control beam.


Author(s):  
E. A. Nikolaeva ◽  
A. N. Timofeev ◽  
K. V. Mikhaylovskiy

This article describes the results of the development of a high thermal conductivity carbon fiber reinforced polymer based on carbon fiber from pitch and an ENPB matrix modified with a carbon powder of high thermal conductivity. Data of the technological scheme of production and the results of determining the physicomechanical and thermophysical characteristics of carbon fiber reinforced polymer are presented. 


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