scholarly journals Contribution of Transverse Reinforcement Configuration on Concrete Shear Capacity of RC Column

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.

Author(s):  
Mikihito Yoshida ◽  
Yasushi Nishimura

For the joints composed of steel beams and reinforced concrete columns, shear failure and bearing failure are the key failure modes. The shear failure indicates stable hysteresis loop without the strength degradation. On the other hand, the bearing failure mode indicates large pinching and strength degration after the attainment of the maximum load.Accordingly, bearing failure in the joints should not be caused in RCS system.To improve the bearing failure behavior of S beam - RC column joint, joint details using perfobond plate connectors were proposed. Perfobond plate connectors were attached on the upper and bottom flanges at right angles to the steel flange. The objective of this study is to clarify the effectiveness of proposed joints details experimentally and theoretically.Six specimens were tested. All specimens were T-shaped planar beam - column joints with 350mm square RC column and S beams with the width of 125mm and the depth of 300mm. The beams were all continuous through the column.Perfobond plate connectors were attached on the bottom flanges at right angles to the steel flange.Three holes were set up in the perfobond plate connectors. The experimental variable was the transverse reinforcement ratio of the joints. The transverse reinforcement ratio of the joints was 0.181% and 0.815%. For each transverse reinforcement ratio of the joints, specimen without the perfobond plate connectors, specimen with the perfobond plate connectors and specimen with the reinforcing bar inserted the hole of perfobond plate connectors were planned.For all specimens, the hysteresis loop showed the reversed S-shape. However, energy dissipation for specimens for specimens with perfobond plate connectors was larger than of specimen without perfobond plate connectors. Bearing strength of specimens with perfobond plate connectors was larger than that of specimen without perfobond plate connectors. From the test results, shear strength of concrete connector a hole was 0.7 times compression strength of concrete.On the other hand, shear strength of inserted reinforcing bar was 1.25 times shear strength of reinforcing bar.Based on the stress transferring mechanism and resistance mechanism of joints proposed by authors, the design formulae of joints with perfobond plate connectors were proposed.The predictions were shown to be in good agreement with the test results.


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).


2022 ◽  
pp. 1-24
Author(s):  
Dimitrios K. Zimos ◽  
Panagiotis E. Mergos ◽  
Vassilis K. Papanikolaou ◽  
Andreas J. Kappos

Older existing reinforced concrete (R/C) frame structures often contain shear-dominated vertical structural elements, which can experience loss of axial load-bearing capacity after a shear failure, hence initiating progressive collapse. An experimental investigation previously reported by the authors focused on the effect of increasing compressive axial load on the non-linear post-peak lateral response of shear, and flexure-shear, critical R/C columns. These results and findings are used here to verify key assumptions of a finite element model previously proposed by the authors, which is able to capture the full-range response of shear-dominated R/C columns up to the onset of axial failure. Additionally, numerically predicted responses using the proposed model are compared with the experimental ones of the tested column specimens under increasing axial load. Not only global, but also local response quantities are examined, which are difficult to capture in a phenomenological beam-column model. These comparisons also provide an opportunity for an independent verification of the predictive capabilities of the model, because these specimens were not part of the initial database that was used to develop it.


2011 ◽  
Vol 94-96 ◽  
pp. 1983-1988
Author(s):  
Jia Song ◽  
Zhen Bao Li ◽  
Yong Ping Xie ◽  
Xiu Li Du ◽  
Yue Gao

An experimental study was made of the mechanical properties of large scale confined concrete subjected to the axial compression test. Eleven tied concrete columns and six plain concrete prisms were tested. In the test, each specimen had the same transverse reinforcement configuration, and similar volumetric ratio of lateral steel, while different size. The test results in this paper indicate that the size of the specimen has no obvious relationship with the ultimate strength, however, it does affect the post-peak ductility to some extent. As a supplement to the experimental study, a finite element method was adopted to imitate the mechanical behavior of the confined concrete under axial compression. The results of the imitation in this paper indicate the confinement mechanism of large scale specimens.


2015 ◽  
Vol 37 ◽  
pp. 247 ◽  
Author(s):  
Hooman Farahmand ◽  
Mohammad Reza Azadi Kakavand ◽  
Shahriar Tavousi Tafreshi ◽  
Pooria Hafiz Hafiz

Experimental research activities and post-earthquake considerations have demonstrated that reinforcedconcrete columns with light or widely spaced transverse reinforcement are vulnerable to shear failure duringearthquakes. According to this point by using failure limit curve, we can assess the effective parameters in shearand axial failure of reinforced concrete columns in framed buildings. In the current study by flexural, shear andaxial springs which are used in series, shear and axial failures and important effective parameters have beenassessed, Besides 5,10 and 15 story models with different amounts of initial axial load ratio have been analyzedby nonlinear push-over analysis. The results of analytical models contain behavior of buildings based on differentinitial axial load ratio and different spacing of transverse reinforcement are compared


Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4938
Author(s):  
Maciej Grabski ◽  
Andrzej Ambroziak

The scope of the paper is to propose a method for determining the size of shear caps in a slab–column-connections-reinforced concrete structure. Usually, shear heads are used to enhance slab–column connection, especially when the transverse reinforcement does not give the required punching shear load capacity. The dimensions of the shear head should provide the punching shear resistance of the connection inside and outside the enhanced region. The process of selecting the size of the shear head is iterative. The parametric analysis of the ACI 318 code and EC2 standard has the objective of indicating which control perimeter (inside or outside the shear head) has a decisive impact on the punching shear capacity of the connection. Based on the analysis, the authors propose methods for selecting the dimensions of the shear head with practical application examples. The paper is intended to provide scientists, civil engineers, and designers with guidelines to design the process of the slab–column connections with the shear caps.


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.


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.


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.


2018 ◽  
Vol 196 ◽  
pp. 02040
Author(s):  
Maria Włodarczyk

Results of experiments carried out on beams with varying shear reinforcement are presented. Depending on the amount of transverse reinforcement different failure modes with different ultimate loads were recorded. The results were compared to theoretical load capacity estimates. Three models for shear capacity were used: classical, EC and Zararis described in the accompanying paper [1]. When shear failure mode governs beam behaviour, theoretical results according to the EC and Zararis are in good compatibility with experiments.


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