Australian Journal of Basic and Applied Sciences. Experimental Study On Diagonally Loaded Rcc Frames With Masonry Infilled Wall

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1 AENSI Journals Australian Journal of Basic and Applied Sciences Journal home page: Experimental Study On Diagonally Loaded Rcc Frames With Masonry Infilled Wall 1 M. Palanisamy, 2 J. Premalatha 1 Department of Civil Engineering Research Scholar, Anna University, Tamilnadu, India 2 Professor and Head of the Department, Department of Civil Engineering Kumaraguru College of Technology, Coimbatore , Tamilnadu, India ARTICLE INFO Article history: Received 19 September 2013 Received in revised form 20 October 2013 Accepted 25October 2013 Available online 18 November 2013 Key words: 2D RCC frame, diagonal load, deflection, strength, stiffness, ductility, energy dissipation ABSTRACT Generally designers neglect these infill walls in as non-structural and treat the frames as conventional reinforced concrete frames. However, the presence of infill the frame alters the overall behavior, especially when the structure is subjected to later loads. The objective of this study was to investigate the behaviour of 2D quarter scale reinforced concrete square frame with various brick infills under diagonal static loading. In this investigation the performance of M20 grade of concrete frame mix designed as per IS method with four types of masonry infilled frames such as reinforced concrete frames without masonry infill (Bare frame), reinforced concrete frames with brick masonry infill, reinforced concrete frames with flyash brick masonry infill and reinforced concrete frames with hallow block masonry infill were cast and studied. The study discusses the strength of the 2D frame under ultimate diagonal loads till failure. Conclusions are made based on the experimental investigations AENSI Publisher All rights reserved. INTRODUCTION Masonry infill panels have been used in reinforcement concrete frame structures as interior and exterior partition walls. Since they are usually considered as nonstructural elements their interaction either the bounding frame is ignored in design. Infill substantially alter the behavior of a building subjected to lateral loads such as wind and earthquake forces; However, when subjected to a strong lateral forces infill walls tend to interact with bounding frame and may induce a load resistance mechanism that is not accounted for the design. The present study aims to evaluate the response of reinforced concrete buildings with infill wall. Previous experimental research on the behaviour of brick infilled RC frames (Achintya et al. 1991: Yawjeng Ciou et al.1999: Diptesh Das et al. 2004: Ismail et al 2004: Marina et al:2006) have shown that the structural behaviour of the framed masonry wall subject to in plane monotonic loading on partial fill masonry wall induce a short column effect leads to severe failures of the column. Further experimental research of Mehmat Emin Kara et al:2006 have shown that partially in filled non-ductile RC Frames exhibited significantly higher ultimate strength and higher initial stiffness than the bare frame. Prabavathy et al (2006) has shown that infill panels can significantly improve the performance of RC Frames. Mrs.Umarani (2008) examined the behaviour of infilled frames (5 storeys) for lateral loading. Test focused on the increase of energy dissipation over and above the base frame. Materials: The following Basic tests are conducted as per IS standards on the materials and the results are tabulated in table1. Table 1: Test on Cement Test Values Cement Specific Gravity 3.15 Fineness 97.6% Consistency 35% Initial Setting Time 35 min Fine Aggregates Specific Gravity 2.58 Free Surface Moisture 1.5% Gradation Zone II Corresponding Author: M. Palanisamy, Department of Civil Engineering Research Scholar, Anna University, Tamilnadu, India Tel: palanisamym@rediffmail.com

2 149 M. Palanisamy and J. Premalatha et al, 2013 Coarse Aggregates Specific Gravity 2.66 Impact Value 26.33% Crushing Values 22.56% Abrasion Value 8% Clay Bricks Compression 5.2 N/mm 2 Water absorption 7.2% Flyash Bricks Compression 0.79 N/mm 2 Water absorption 0.78% Solid Bricks Compression 8.0 N/mm 2 Water absorption 2.67% Description of the Model and Reinforcement: Reinforced concrete frame specimens are prepared M20concrete of grades which mix proportions are arrived using IS method. The 2D test specimen was reduced to quarter scale square model RC frame. The model consists of inner to inner dimensions of the frame specimens are 600mmx6000mm, with cross sections of 150mmx150mm. To cast the frame, the wooden mould made up of plywood used as shown in figure 1. The main reinforcement used for all the specimens was four numbers of 8 mm diameter HYSD bars. The stirrups 6 mm diameter were in the form of closed square two-legged HYSD bars, provided at 150mm c/c spacing as shown in fig.1. The loading diagonals were provided same cross section of the frame. Cement mortar 1:5 used for various infill materials. Casting and Curing: M 20 concrete mix is prepared using Ordinary Portland Cement, uniformly graded sand, well graded aggregate 20mm and potable water as per IS: M 20 grade of Concrete was machine mixed and poured. Concrete was properly placed and compacted beneath and also on the sides of the frame using a needle vibrator as shown in figure 2. The sides of the frame were removed after 24 hours of casting. The specimen was cured kept moist by sprinkling water frequently for a period of 28 days from the day of casting. After 7 days the various infill like ordinary bricks, flyash bricks and solid blocks were infilled with cement mortar 1:5 and cured for a period of 28days. Fig. 1: Formwork for 2D Frame Fig. 2: Casting of 2D Frame Experimental Setup and Testing: The load frame and the loading jack along with proving ring are arranged in such a way to apply the concentrated force diagonally on the specimen as shown in fig 3, fig.4 fig.5 and fig.6. To start with, the frame was loaded with small loads and then unloaded to check the effectiveness of the instrument setup and loading. This process was repeated till the readings were consistent. The frame was subjected to static loading. The frames specimens of various infills are subjected to failure and hence the ultimate loads are determined.

3 150 M. Palanisamy and J. Premalatha et al, 2013 Fig. 3: Test set up for 2D Frame Fig. 4: Test set up for Brick infill Fig. 5: Test set up for Flyash Brick infill Fig. 6: Test set up for Solid Brick infill Investigation of 3D RC Fame: The results of experimental investigation carried out the behaviour of 2D quarter scale reinforced concrete square frame with various brick infills under diagonal static loading are presented in table 2. Masonry infilled reinforced cement concrete frames are subjected to ultimate loads till failure. Visible crakes first appeared at the joints and propagated along the diagonals. From the investigations it is observed that the failure patterns of various infill of reinforced concrete frames are more ductile compared to conventional reinforced concrete frames. Table 2: Ultimate Loads on RCC Frames with various infills Specimens First crack Load in kn Ultimate Load in kn Bare frame Frame with Brick Infill Frame with Flyash Infill Frame with Solid Infill Behaviour And Model Failure: First crack was observed at 8kN at the junction of loaded side of the bare frame and ultimate load is achieved at 12.6kN. In the brick infill frame is 26kN in the first crack at the brick infill and the load is increased to36kn is the ultimate load of in the frame. In the flyash infill wall frame is loaded in the first crack 25kN at the layers of opened and the ultimate load is reached at28kn.intial crack is observed solid infill at 52kN and the ultimate load is 68kN. The crack patterns are shown in the fig7 to fig 10. Fig. 7: Crack pattern of 2d Frame Fig. 8: Crack pattern of Brick infill

4 151 M. Palanisamy and J. Premalatha et al, 2013 Fig. 9: Crack pattern of Flyash infill Fig. 10: Crack pattern of Solid infill RESULT AND DISCUSSIONS First Crack Load Of Various Infills: The first crack observed in the experimental results of the 2D bare frame model were compared with 2D brick infill frame, 2D flyash infill frame and 2D solid brick infill frame model results as shown in the fig.11. FIRST CRACK LOAD IN VARIOUS INFILLS LOAD IN kn BARE BRICK FLYASH SOLID 52 Fig. 11: First crack load of various infills Ultimate Load Of Various Infills: The ultimate load in the experimental results of the 2D bare frame model were compared with 2D brick infill frame, 2D flyash infill frame and 2D solid brick infill frame model results as shown in the fig.12. ULTIMATE LOAD OF VARIOUS INFILLS LOAD IN kn BARE BRICK FLYASH SOLID Fig. 12: Ultimate loads of various infills

5 152 M. Palanisamy and J. Premalatha et al, 2013 Comparison Between Bare Frame And Infilled Frame: There is a considerable difference in the ultimate load of bare frame and infilled frames. Comparing bare frame the brick infill frame is almost three time the ultimate load is increased, flyash frame is double time increasing the ultimate load and the solid infill frame is five times increased ultimate load. Conclusion: In this paper diagonally loaded RCC frames has been studied that includes bare frame, brick masonry infilled frame, Flyash masonry infilled frame and solid masonry infilled frame. From the diagonally loaded RCC frames following conclusions are drawn, There is an increase ultimate load of 185% Brick infill Frame, 120% Flyash brick infill Frame, and 440% Solid infill Frame when compared to RCC frame with no infill (Bare frame). Also there is an increment of ultimate load 30% Brick infill Frame, and 143% Solid infill Frame when compared to RCC Frame infill with Flyash Brick Masonry. Infill Frame specimen while apply the loads in diagonally the cracks are formed (first crack) at the infill portion and the cracks are extended in diagonally. The presence of infill wall can increase the strength of the structure. In case of bare frame, the ultimate load is very less than the other infilled frames, which may cause the collapse of the frames during strong earthquake shaking. Therefore the infilled frame structures will be the better option to prefer in the seismic region. REFERENCES Bureau of Indian Standards code, IS , Plain and reinforced concrete-code of Practice, BIS, New Delhi, India. Bureau of Indian Standards code, IS , Criteria for earthquake resistant design of structures, Part I: General provisions and Buildings, Fifth revision, BIS, New Delhi, India. Bureau of Indian Standards code, IS , Criteria for earthquake resistant design of structures, Part I: General provisions and Buildings, Fifth revision, BIS, New Delhi, India. Seung Y. Lee and Achintya Haldar, Reliability of Frame and Shear Wall Structural Systems under Static Loading, Journal of Structural Engineering., 129(2): Yaw-Jeng Chiou, Jyh-Cherng Tzeng, and Yuh- Wehn Liou, Experimental and Analytical Study of Masonry Infilled Frames, Journal of Structural Engineering, 125(10): Ýsmail, H., Çag atay, Failure of an industrial building during a recent earthquake in Turkey, Engineering Failure Analysis, 12(4): Melhmet Mehmet Emin Kara, Altin Sinan, Behavior of reinforced concrete frames with reinforced concrete partial infills, ACI structural journal, 103(5): Prabavathy, S., M.S. Palanichamy and A.R. Santhakumar, Behaviour of reinforced hollow block masonry infill in multistory RC frames under lateral loading, Indian Concrete Journal, 80(9). Murtthy, C.V.R., and Das, Diptesh., Beneficial Effects of Brick Masonry In Fills In Seismic Design of RC Frame buildings Engineering Structures Journal, 21(4): Durgesh, C., Rai, S.K. Thakkar, and U. Ramesh, Behaviour of seismic and non-seismic RC frames under cyclic loads, The Indian Concrete Journal, pp: Kodar, V.K.R., M.A. Erki and J.H.P. Quenneville, Seismic Analysis of Infilled Frames, Journal of Structural Engineering, 25(2): Chethan, K., R. Ramesh babu and et al, Influence of masonry infill on fundamental natural frequency of 2D RC frames, Journal of Structural Engineering, 37(2): Dudey, S.K. and S.V. Deodhar, Ultimate strength of infilled frames under horizontal load, Journal of Structural Engineering, 23(3): D.guney and A.O. Kuruscu, Optimization of the configuration of infill walls in order to increase seismic resistance of building structures, International Journal of Physical sciences, 6(4): Mulgund, G.V. and A.B. Kulkurni, Seismic assessment of RC frame buildings with brick masonry infills, International Journal of advanced engineering sciences and technologies, 2(2): Kashif Mahmud, Md.Rashadul Islam and Md. Al-Amin, Study the reinforced concrete frame with brick masonry infill due to lateral loads, International Journal of Civil and Environmental Engineering, 10(4): Imran, I., A. Aryanto, Behavior of reinforced concrete frames with lightweight materials under seismic loads, Civil Engineering Dimension, 11(2):