scholarly journals BEHAVIOR OF LIGHTWEIGHT SELF-COMPACTED CONCRETE USING ATTAPULGITE STONE AS AGGREGATE AND SUBJECTED TO AXIAL LOAD

2021 ◽  
Vol 25 (Special) ◽  
pp. 4-78-4-87
Author(s):  
Heba S. Qassim ◽  
◽  
Wissam K. AL-Saraj ◽  

This paper presents experimental studies of rectangular concrete beam behaviors under axial load and bending loads and investigating the possibility of producing Lightweight Self-Compacting Concrete (LWSCC) by using the Attapulgite stone with a bulk density of about 776 kg/m3. The experimental work included (5) specimens which included using the silica fume by 10% and 15% as an addition to the mixture M2 and M3 . The shear span to effective depth (a/d) of beams was (2.5, 2.75, and 3.00). The test results showed an improvement in the mechanical properties of specimens containing silica fume by 15%, which was tested at 28 days. The first crack and the ultimate load were decreasing with increasing (a/d) ratios. Experimental results indicate a significant improvement in the properties of concrete and its resistance to shear stresses, as the axial load improves the shear capacity and reduces the shear failure in the (LWSCC).

2020 ◽  
Vol 8 (3) ◽  
pp. 127-136
Author(s):  
Taufiq Saidi ◽  
Rudiansyah Putra ◽  
Zahra Amalia ◽  
Munawir Munawir

Proper design of transverse reinforcement in the RC column is needed to maintain its ability to deform under axial and shear load safely. Even though mandatory building codes for transverse support of the RC column exist, shear failure was still found in the last high earthquake in Pidie, Aceh, in 2016. Therefore, as an attempt to improve RC column strength and elasticity, the effect of transverse reinforcement configuration was evaluated experimentally to a column subjected to an axial and shear load. The experiment was conducted by using four-column specimens with a cross-section 200 x 200 mm. Four types of transverse reinforcement configurations were applied in each column. The test was carried out by loading an axial load always and shear load gradually until its failure. The test results show that the configuration of transverse reinforcement has a significant effect of maintaining column stiffness, which was subjected to compressive axial load and shear load. Furthermore, the arrangement of transverse reinforcement influences the compressive strength significantly and enhance the concrete shear capacity of a column due to its confinement effect.


2019 ◽  
Vol 3 (2) ◽  
pp. 105
Author(s):  
Arga Saputra ◽  
Sri Murni Dewi ◽  
Lilya Susanti

Initial design errors, especially the installation of stirrups, one of them can cause the beam having shear failure due to installing capacity of stirrups less than the shear capacity that occurs. Shear strengthening in this study used externally stirrups ∅6-75 which were installed in the shear area only. The results of calculation analysis, shear capacity can increase up to 137.82%; 133.42% and 137.12% while the test results increased by 31.58%; 0% and 4.76% in this caseload did not look significant from the results of calculation analysis. However, when viewed from crack pattern that occurs without external stirrups, outer ring has a combination of flexural and shear cracks occurs quite much, besides of flexural and shear cracks, combination of crack also occurs because of pressure beam reach pressure capacity first rather than tensile beam because the ratio of installed reinforcement is over reinforced. Meanwhile, in the beam with external stirrups, the crack pattern that occurs is also a combination of bending and shear cracks, but the cracks that occur are relatively less than the beam without external stirrups. When viewed from the deflection that occurred during the first crack, the reinforced beam experienced a relatively smaller deflection of 0.61 mm beam; 0.31 mm and 0.18 mm rather than beams without externally stirrups 1.28 mm; 0.55 mm and 0.32 mm, so that the beam with external stirrups can be said to be more rigid than the beam without external stirrups. Kesalahan desain awal, khususnya pemasangan sengkang, salah satunya dapat mengakibatkan balok mengalami kegagalan geser akibat kapasitas sengkang yang terpasang kurang dari kapasitas geser yang terjadi. Perkuatan geser pada penelitian ini menggunakan sengkang ∅6-75 yang dipasang pada daerah geser saja. Hasil dari perhitungan analisis, kapasitas geser dapat meningkat sampai 137,82%; 133,42% dan 137,12% sedangkan dari hasil pengujian mengalami peningkatan sebesar 31,58%; 0% dan 4,76% dalam hal ini peningkatan beban tidak terlihat sesignifikan dari hasil analisis perhitungan, namun jika dilihat dari pola retak yang terjadi beton tanpa perkuatan sengkang luar mengalami kombinasi retak lentur dan geser yang cukup banyak, selain kombinasi retak lentur dan geser, juga terjadi retak akibat balok tekan yang mencapai kapasitas tekan terlebih dahulu daripada balok tarik karena rasio tulangan yang terpasang over reinforced. Sementara itu pada balok dengan perkuatan sengkang luar, pola retak yang terjadi juga kombinasi retak lentur dan retak geser, namun retak yang terjadi relatif lebih sedikit daripada balok tanpa perkuatan. Jika ditinjau dari lendutan yang terjadi pada saat crack pertama, balok yang diberi perkuatan mengalami lendutan yang relatif lebih kecil yaitu 0,61 mm; 0,31 mm dan 0,18 mm daripada balok tanpa perkuatan 1,28 mm; 0,55 mm dan 0,32 mm sehingga balok yang diperkuat dengan sengkang luar dapat dikatakan lebih kaku daripada balok tanpa perkuatan.


Buildings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 402
Author(s):  
Monthian Setkit ◽  
Satjapan Leelatanon ◽  
Thanongsak Imjai ◽  
Reyes Garcia ◽  
Suchart Limkatanyu

For decades, recycled coarse aggregate (RCA) has been used to make recycled aggregate concrete (RAC). Numerous studies have compared the mechanical properties and durability of recycled aggregate concrete (RAC) to those of natural aggregate concrete (NAC). However, test results on the shear strength of reinforced recycled aggregate concrete beams are still limited and sometimes contradictory. Shear failure is generally brittle and must be prevented. This article studies experimentally and analytically the shear strength of reinforced RAC beams without stirrups. Eight RAC beams and two controlled NAC beams were tested under the four-point flexural test with the shear span-to-effective depth ratio (a/d) of 3.10. The main parameters investigated were the replacement percentage of RCA (0%, 25%, 50%, 75%, and 100%) and longitudinal reinforcement ratio (ρw) of 1.16% and 1.81%. It was found that the normalized shear stresses of RAC beams with ρw = 1.81% at all levels of replacement percentage were quite similar to those of the NAC counterparts. Moreover, the normalized shear stress of the beam with 100% RCA and ρw = 1.16% was only 6% lower than that of the NAC beam. A database of 128 RAC beams without shear reinforcement from literature was analyzed to evaluate the accuracy of the ACI 318-19 shear provisions in predicting the shear strength of the beams. For an RCA replacement ratio of between 50% and 100%, it was proposed to apply a reduction factor of 0.75 to the current ACI code equation to account for the physical variations of RCA, such as replacement percentage, RCA source and quality, density, amount of residual mortar, and physical irregularity.


Author(s):  
Tran Xuan Vinh ◽  
Nguyen Trung Hieu ◽  
Pham Xuan Dat ◽  
Nguyen Manh Hung

Currently, RC flat slabs are being used commonly because of their advantages. Punching shear failure is one of the governing failure modes of RC flat slabs without column capital and drop panels. In this paper, the provisions for predicting the punching shear capacity of two-way reinforced concrete (RC) flat slabs without shear reinforcement including ACI 318-19, Eurocode 2 and TCVN 5574:2018 provisions are reviewed by mean of considering the influences of the main parameters (effective depth, compressive strength of concrete, loaded area, reinforcement ratio). A total of 169 test results collected from the literature were used to compare with the provisions. The aim of this study was to evaluate the level of applicability of predicting the punching shear capacity of two-way RC flat slabs according to these provisions. The comparison results indicated that the Eurocode 2 provision provides the most accurate prediction of punching shear capacity of two-way RC flat slabs.


2015 ◽  
Vol 1125 ◽  
pp. 94-99 ◽  
Author(s):  
Aldyandra Hami Seno ◽  
Eko Koswara ◽  
Hendri Syamsudin ◽  
Djarot Widagdo

This research was done to evaluate the bending behavior (load-deflection curve and failuremode) of sandwich structures using Tali Bamboo strips as sandwich skin material. Bending tests wereconducted on sandwich specimens with end grain balsa (3-point bending) and polypropylene (PP)honeycomb cores (4-point bending) to evaluate their bending behavior. From the test results,analytical and numerical models were developed to simulate the observed bending behavior. Themodels are able to simulate the pre-failure bending behavior and failure modes (core shear failure) ofthe specimens. It is also shown that for thin (length/thickness > 20) sandwiches the models are moreaccurate since shear effects are less prominent. With the obtained models a predictive comparison isdone between the PP and balsa cored specimens since the testing configuration for each type wasdifferent. The analysis results show that balsa cored specimens are able to withstand higher transversebending loads due to the higher shear strength of the balsa core. These prediction results are to beproven by specimen testing which is the subject of future research.


2008 ◽  
Vol 24 (2) ◽  
pp. 493-511 ◽  
Author(s):  
Eric J. Setzler ◽  
Halil Sezen

This research is focused on modeling the behavior of reinforced concrete columns subjected to lateral loads. Deformations due to flexure, reinforcement slip, and shear are modeled individually using existing and new models. Columns are classified into five categories based on a comparison of their predicted shear and flexural strengths, and rules for combining the three deformation components are established based on the expected behavior of columns in each category. Shear failure in columns initially dominated by flexural response is considered through the use of a shear capacity model. The proposed model was tested on 37 columns from various experimental studies. In general, the model predicted the lateral deformation response envelope reasonably well.


2016 ◽  
Vol 835 ◽  
pp. 450-454
Author(s):  
Dickson Fong Wen Jing ◽  
Lau Teck Leong

This paper reports test results of flat slab cast from micro-concrete and normal concrete subjected to concentric punching shear. Although the punching shear failure mechanism of micro-concrete slabs was very similar to that of normal-concrete slabs, the punching shear capacity is reduced to about 73% due to the reduction in transferred shear stresses across shear cracks by aggregate interlock. Therefore, a shear retention factor of 0.7 is suggested to be applied in estimating the punching shear strength of micro-concrete slabs.


2018 ◽  
Vol 1 (4) ◽  
pp. 877-884
Author(s):  
Yarmiza Anggriyani Fitri ◽  
Teuku Budi Aulia ◽  
Taufiq Saidi

Abstract: The development and progress of the world quite rapidly accrue followed by a large number of the population led to an increase in the outstanding in the use of concrete. Concrete is widely used in the construction of the building works and means of transportation such as bridges, highways and other worksBasically the concrete has a high compressive strength, but had the ability to wiht stand the tensile and shear forcew low. This can be fixed by added a fibber on mortar concrete.  The addition of fiber for decreasing the brittle and improving the survival of crack early (first crack) is a concrete it can be reached by adding polypropylene fiber, bendrat wire fiber and rubber tiress fiber. The purpose of this research is to observe the shear behavior of reinforced concrete beam  with fiber is polypropylene fiber (PP), bendrat wire fiber and used rubber tiress. In this study 4 beams tested with measuring 15 x 30 x 220 cm each fiber type has a beam specimen and a beam specimen without the addition of fiber. Specimens designed for shear failure. The result showed all the beams are having shear failure as planned. Cement water factor (FAS) 0.25, bendrat wire fiber with a percentage of 2% of the volume of the concrete. The results showed a beam experiencing failed to slide as planned. The test results showed a beam BMT with the addition of fiber has a maximum load 26.03 tonnes, the first cracks occur on the load 5.10 tons. Beam with wire bendrat maximum load wire BMT 27.41 T, the first cracks occur on the load 5.90 T. For the magnitude of the shear style capacity contributed by shear reinforcement constann for all beams this is 1.653 T, while for a capacity of sliding style concrete donated by each to BMT fiber without adding Vc = 4.52 T and fiber wire bendrat BMT value of Vc = 4.55 T. Abstrak: Perkembangan dan kemajuan dunia yang cukup pesat diikuti dengan bertambah banyaknya jumlah penduduk mengakibatkan terjadinya peningkatan yang menonjol dalam penggunaan beton. Beton digunakan secara luas pada pekerjaan-pekerjaan pembangunan gedung dan sarana-sarana transportasi misalnya jembatan, jalan raya serta pekerjaan-pekerjaan lainnya. Pada dasarnya beton memiliki kuat tekan yang tinggi, tetapi memiliki kemampuan menahan gaya tarik dan gaya geser yang rendah. Hal ini dapat diperbaiki dengan menambahkan serat pada adukan beton. Penambahan serat untuk mengurangi sifat getas dan meningkatkan ketahanan retak awal (first crack) beton yang dapat ditempuh salah satunya dengan menambahkan serat kawat bendrat, dan serat karet ban bekas dalam campuran beton. Tujuan dari penelitian ini adalah untuk mengamati perilaku geser balok beton bertulang mutu tinggi (BMT)  menggunakan serat kawat bendrat. Pada pengujian ini diuji  dua balok berukuran 15 x 30 x 220 cm, dengan satu balok tanpa penambahan serat dan satu balok jenis serat sebanyak satu benda uji didesain mengalami gagal geser. Faktor air semen (FAS) 0,25 serat kawat bendrat dengan persentase 2% dari volume beton. Hasil penelitian menunjukkan balok mengalami gagal geser sesuai yang direncanakan. Hasil pengujian menunjukkan balok BMT dengan penambahan serat memliki beban maksimum 26,03 ton, retak pertama terjadi pada beban 5,10 ton. Balok BMT kawat bendrat beban maksimumnya 27,41 ton, retak pertama terjadi pada beban 5,90 ton. Untuk besarnya kapasitas gaya geser yang disumbangkan oleh tulangan geser konstann untuk semua balok yaitu 1,653 ton, sedangkan untuk kapasitas gaya geser yang disumbangkan oleh beton masing- masing untuk BMT tanpa penambahan serat Vc = 4,52 ton dan beton BMT serat kawat bendrat nilai Vc = 4,55 ton.


2018 ◽  
Vol 162 ◽  
pp. 04003
Author(s):  
Kaiss Sarsam ◽  
Raid Khalel ◽  
Nisreen Mohammed

In structural engineering (RC, steel, etc.) it is usual to base the shear strength of members on the web only- e.g. in RC the stirrups used are usually called “web reinforcement”. Presently all codes, and several researches, base the strength of members on the capacity of the web alone. 93 tests of T-beams failing in shear available from the literature are studied in this work to estimate the influence of flanges on the shear capacity of RC beams. These include 32 ones without web reinforcement and 61 with stirrups. Comparison between test results and theoretical shear capacity show that all available equations conservatively estimate the occurrence of shear failure. In this work an equation for predicting the contribution of the flange to shear capacity in T-beams is presented. The best available design method obtained from the literature leads to a coefficient of variation (COV) of 17.58% compared to 13.46% for the proposed design method in this work.


2021 ◽  
Vol 25 (Special) ◽  
pp. 4-115-4-126
Author(s):  
Liwaa Abd Alhussen ◽  
◽  
Layth A. Al-jaberi ◽  
Ra’id F. Abbas ◽  
◽  
...  

The reaction of column to flat slabs may cause what is known as “punching shear stresses” when the stress is normally concentrated within the perimeter around the loaded area. In general, the reinforced concrete slabs are not designed for any shear failure due to the sudden nature of this type of failure. Many solutions can be followed to overcome such issue like increasing the depth of slab and diameter of columns. Increasing the slab thickness may add extensive dead loads and can breaks the economy justifications of this structural member. On the other hand, increasing the diameter of any column may un accepted due to architectural purposes. The high performance concrete is such type of concrete that illustrate high levels of mechanical performance “structural behavior as a consequence” if compared with normal concrete. Due to that, the high performance concrete may give good alternative an exceeds the problem of punching as a result. The basic aim of this study is to propose a brief review regarding this field of research. However, this study is divided to three parts, the first is devoted to view a suitable background about the punching shear capacity of traditional concrete slabs. The second part is registered to view the past experience in reinforced concrete slabs punching capacity and have steel fibers while the second part is devoted to present the state of art concerning the punching shear of high performance concrete slabs.


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