conventional push-off specimens with an initially uncracked interface with steel transverse 170. reinforcement was carried out by Ibell & Burgoyne (1999) assuming an S-sha[r]

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Inclusion of steel fibers to **concrete** progresses the flexural and tensile capacities of **concrete**. Consequently the **shear** **capacity** of **concrete** flexural members improve. Predicting the **shear** **capacity** of **concrete** beams containing steel fiber is an important issue not only in structural design but also to retrofitting of existing structures. Since there are several variables to assess the **shear** **capacity** of steel fiber **reinforced** **concrete** (SFRC) beams, presenting a suitable equation is a complicated task. The aim of the present paper is to evaluate an empirical formulae based stepwise regression (SR) method for **shear** **capacity** of SFRC beams. A series of reliable **experimental** data has been provided from literatures for model development. The obtained **results** based SR model were compared with **experimental** data in training and testing state. A practical formulae based SR method has been developed for **shear** **capacity** assessment of SFRC beams. Besides, several equations based models also presented to compare with the equation based SR model. The comparison showed the SR formulae gives the most exact accuracy than others in terms of **shear** **capacity** assessment of SFRC beams.

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There is a few design and prediction models related to the punching **shear** strength of **concrete** slabs **reinforced** with FRP composite bars. This paper evaluates the accuracy of the available punching **shear** equations for FRP-RC slabs in the models of CSA S806 (CSA 2012) [8], ACI-440.1R-15 (ACI 2015) [9], BS 8110 (BSI 1997) [10], JSCE (1997) [11], El-Ghandour et al. [12], Matthys and Taerwe [2], Ospina et al. [3] and El-Gamal et al. [12] . The accuracy of the design equations and different models was assessed by comparing their predictions against the **experimental** **results**. This paper also presents a simple yet improved model to calculate the punching **shear** **capacity** of FRP-**reinforced** **concrete** slabs. The performance of the proposed model is also compared to that of punching **shear** design provisions and a number of models propsed by some researches.

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Although further **experimental** data is required to verify the above proposed failure criteria, the **results** suggest that while at the lower strain-rates the increase from the static case is only by 7%, for strain-rates of 100 and 300/s, the respective increases are 33% and 73%, which are very signi ﬁ cant. For strain-rates higher than 300/s, which can be the case in ballistic problems, the strain-rate dependent relationships for the materials used in the model and the contribution of aggregate interlock would need to be reviewed to consider additional mechanisms such as aggregate crushing. Fig. 11. Idealisation of aggregate particles into spheres (after [58]).

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The typical failure mode of the beam is illustrated in Fig. 3, whereas Table 3 summarized the prediction and **experimental** **results** of all the tested beams. Beam failed on diagonal **tension** **shear** experienced formation of diagonal crack in the **shear** span zone followed by **concrete** crushing in the loading point zone (BGM-03), sudden formation of diagonal crack in the **shear** span zone followed by beam failure (BGM-04) or formation of diagonal crack growth gradually in the **shear** span zone followed by beam failure after yielding of longitudinal reinforcement (BSM-03 and BSM-04).While other beams which failed on flexural experienced by rupture of tensile longitudinal reinforcement or **concrete** crushing on the top of compression zone. For both beam types, the amount of flexural crack in case of beam with shorter **shear** span length less than that beam with longer **shear** span length. Also, the occurrence of diagonal **shear** crack was not clearly seen in the **shear** span zone.

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The typical failure mode of the beam is illustrated in Fig. 3, whereas Table III summarized the prediction and **experimental** **results** of all the tested beams. Beam failed on diagonal **tension** **shear** experienced formation of diagonal crack in the **shear** span zone followed by **concrete** crushing in the loading point zone (BGM-03), sudden formation of diagonal crack in the **shear** span zone followed by beam failure (BGM-04) or formation of diagonal crack growth gradually in the **shear** span zone followed by beam failure after yielding of longitudinal reinforcement (BSM-03 and BSM-04).While other beams which failed on flexural experienced by rupture of tensile longitudinal reinforcement or **concrete** crushing on the top of compression zone. For both beam types, the amount of flexural crack in case of beam with shorter **shear** span length less than that beam with longer **shear** span length. Also, the occurrence of diagonal **shear** crack was not clearly seen in the **shear** span zone.

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Rupert G. Williams et, al [8] displayed an attempt to find out numerical reaction of a seismically designed SDOF structure to blast loading. A portal frame was designed in Northen Trinidad to resist the blast load. 500 kg of charge weight of TNT was used and different standoff distance of 45, 33, 20 meters were taken. By using empirical methods the blast load was determined. From this study it is showed that the designed SDOF model entered the plastic region due to the blast load in a critical standoff distance. Edward Eskew & Shinae Jang [9] carried out a systematic approach determine the causes and **results** of terrorist attacks. The better way to understand the impact of terror is to understand the nature of the attack. Different type of explosions, including physical, chemical, electrical and nuclear was provided in this report. Impact from an explosion is obtained from analytical and **experimental** methods. **Analysis** technique for a damaged structure is also explained in depth. From this knowledge of an explosion the damage of the structure can be determined or detailed models could be developed to calculate the damage that has happened already.

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Abstract—This study aims to determine the efficiency of using Fiber **Reinforced** Polymers (FRP) systems to strengthen the slab–column connections **subjected** to punching **shear**. The used strengthening systems consisted of external FRP stirrups made from glass and carbon fibers. The stirrups were installed around the column. Also, external steel links were used as a conventional strengthening method for comparison. Over the last few years, the use of FRP for strengthening of **concrete** structures has been investigated by many researchers, whichconcerning with the strengthening of **reinforced** **concrete** slabs, beams and columns. The use of FRP in strengthening **concrete** slabs in flexure is done by bonding it to the **tension** face of the slabs. The use of FRP for strengthening the flat slabs against punching **shear** can be considered as a new application. This research shows the **results** obtained from an **experimental** investigation of 4 half-scale two-way slab-column interior connections, which were constructed and tested under punching **shear** caused by centric vertical load. The research included one unstrengthened specimen, which considered as control specimen, one specimen strengthened with steel links, one specimen strengthened with external stirrups made from Glass Fiber **Reinforced** Polymer (GFRP), and one specimen strengthened with external stirrups made from Carbon Fiber **Reinforced** Polymer (CFRP). So, the type of strengthening material is the basic parameter in this study. The **experimental** **results** showed a noticeable increase in punching **shear** resistance and flexural stiffness for the strengthened specimens compared to control specimen. Also, the strengthened tested slabs showed a relative ductility enhancement. Finally, equations for punching **shear** strength prediction of slab-column connections strengthened using different materials (Steel, GFRP & CFRP) were applied and compared with the **experimental** **results**.

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ABSTRACT: This study is part of a larger research work aimed to study the effects of fiber content, fiber type (corrugated shape and hooked-end), amount of web reinforcement and axial compression stress, on the **shear** behavior of high strength fiber **reinforced** **concrete** (HSFRC) beams. To the author’s knowledge, the effect of applying axial compression forces, to the HSFRC beams, has not yet been studied. Nineteen simply supported HSFRC beams were **subjected** to axial compression forces and tested under two-point vertical loading for three values of **shear** span to depth ratio. It was found that the **shear** strength of beams **subjected** to axial compression stress level equals 0.1, is higher than that in the literature for beams tested without applying axial stress by a range of 22% -98%. Increasing the axial compression stress level to 0.2 led to an increase in the first crack load, ultimate load by 24% and 10%, a reduction in the deflection by (19-30%), compared with those **subjected** to axial compression stress level equals 0.1. In addition, a combination of web reinforcement and fibers resulted in a significant increase in the cracking and ultimate loads by 123 and 59%, respectively, over those of the reference beam. A new formula is proposed for predicting the **experimental** **shear** strength of HSFRC beams **subjected** to axial compression forces. The **results** obtained by the proposed formula are in better agreement with the test **results** when compared with the predictions based on the empirical equations proposed by other investigators.

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This paper presents the **results** of an extensive **experimental** campaign on 16 flat-slab specimens with and without punching **shear** reinforce- ment. The tests aimed to investigate the influence of a set of mechan- ical and geometrical parameters on the punching **shear** strength and deformation **capacity** of flat slabs supported by interior columns. All specimens had the same plan dimensions of 3.0 x 3.0 m (9.84 x 9.84 ft). The investigated parameters were the column size (ranging between 130 and 520 mm [approximately 5 and 20 in.]), the slab thickness (ranging between 250 and 400 mm [approximately 10 and 16 in.]), the **shear** reinforcement system (studs and stirrups), and the amount of punching **shear** reinforcement. Systematic measurements (such as the load, the rotations of the slab, the vertical displace- ments, the change in slab thickness, **concrete** strains, and strains in the **shear** reinforcement) allow for an understanding of the behavior of the slab specimens, the activation of the **shear** reinforcement, and the strains developed in the **shear**-critical region at failure. Finally, the test **results** were investigated and compared with reference to design codes (ACI 318-08 and EC2) and the mechanical model of the critical **shear** crack theory (CSCT), obtaining a number of conclu- sions on their suitability.

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Abstract: This paper presents the **results** of a two-phase **experimental** program investigating the punching **shear** behavior of FRP RC flat slabs with and without CFRP **shear** reinforcement. In the first phase, problems of bond slip and crack localization were identified. Decreasing the flexural bar spacing in the second phase successfully eliminated those problems and resulted in punching **shear** failure of the slabs. However, CFRP **shear** reinforcement was found to be inefficient in enhancing significantly the slab **capacity** due to its brittleness. A model, which accurately predicts the punching **shear** **capacity** of FRP RC slabs without **shear** reinforcement, is proposed and verified. For slabs with FRP **shear** reinforcement, it is proposed that the **concrete** **shear** resistance is reduced, but a strain limit of 0.0045 is recommended as maximum strain for the reinforcement. Comparisons of the slab capacities with ACI 318-95, ACI 440-98 and BS 8110 punching **shear** code equations, modified to incorporate FRP reinforcement, show either overestimated or conservative **results**.

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Previous researcher, Marsono (2000) has conducted an **experimental** work on small scaled model of various types of **shear** walls structure. **Results** from the experiment in the form of stresses and strains, crack distributions and ultimate strength then used to establish the analytical method (Continuous Connection Method, CCM) of **analysis**. The non-linear finite element **analysis** (NLFEA) was performed as a tool to affirm the **experimental** **results** and the analytical mode of failure and ultimate strength predictions. The **experimental** and NLFEA **results** were in very close agreement in predicting the ultimate strength and mode of failure of coupled **shear** wall structure.

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Ultimate method of design was introduced in the early sixties of last century. Research work on the ultimate flexural **capacity** of a section was successfully completed with in few years. To predict the flexural **capacity**, equations were developed, whose **results** were in good agreement with the actual/**experimental** values. Mechanism of flexural failure of a rectangular **reinforced** **concrete** beam was much simpler to understand as compared to **shear** failure. In fact **shear** failure of **reinforced** **concrete** beams is a very complex phenomenon due to involvement of too many parameters. Factors influencing the **shear** **capacity** of beams are **shear** span to depth ratio (a/d), **tension** steel ratio (ρ), compressive strength of **Concrete** (f c ΄),

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According to the modelling result as explained in the above topics, the numerical simulation by using ABAQUS software could produce the result as closed as an **experimental** result. The non-linear material models which are available in the ABAQUS/Explicit material library such as Drucker-Prager and Cap-Plasticity that represent Ductile behavior give better and realistic **results** than the Brittle-Cracking model (Damage **Concrete** Plasticity). Furthermore, finite element **analysis** by using ABAQUS software is capable of developing reasonable and realistic estimations available in order to investigate the possible damage modes of **reinforced** **concrete** slabs under impact loads.

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The benchmark CASH, organized by OCED-NEA, will gather international engineers and researchers on common exercises consisting of studying **reinforced** **concrete** **shear** wall **capacity**. The present article presents the first exercise proposed to the participants, base on the SAFE **experimental** tests. Four **shear** walls of entire programme have been selected for the purpose of this benchmark. Each participating team is invited to produce their best estimate calculation to evaluate the response of the specimens under static (monotonic and cyclic) and dynamic loading. The comparison of the modelling methods and the **results** of the participants will be released in November 2015 at the occasion of a workshop that will be held in Paris. The conclusions will be used for the second phase of the benchmark, where a full-scale **shear** wall of an NPP building will be studied.

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Abstract: For **shear**-critical structural elements where the use of stirrups is not desirable, such as slabs or beams with reinforcement congestion, steel fibers can be used as **shear** reinforcement. The contribution of the steel fibers to the **shear** **capacity** lies in the action of the steel fibers bridging the **shear** crack, which increases the **shear** **capacity** and prevents a brittle failure mode. This study evaluates the effect of the amount of fibers in a **concrete** mix on the **shear** **capacity** of steel fiber **reinforced** **concrete** beams with mild steel **tension** reinforcement and without stirrups. For this purpose, twelve beams were tested. Five different fiber volume fractions were studied: 0.0%, 0.3%, 0.6%, 0.9%, and 1.2%. For each different steel fiber **concrete** mix, the **concrete** compressive strength was determined on cylinders and the tensile strength was determined in a flexural test on beam specimens. Additionally, the influence of fibers on the **shear** **capacity** is analyzed based on **results** reported in the literature, as well as based on the expressions derived for estimating the **shear** **capacity** of steel fiber **reinforced** **concrete** beams. The outcome of these experiments is that a fiber percentage of 1.2% or fiber factor of 0.96 can be used to replace minimum stirrups according to ACI 318-14 and a 0.6% fiber volume fraction or fiber factor of 0.48 to replace minimum stirrups according to Eurocode 2. A fiber percentage of 1.2% or fiber factor of 0.96 was observed to change the failure mode from **shear** failure to flexural failure. The **results** of this presented study support the inclusion of provisions for steel fiber **reinforced** **concrete** in building codes and provides recommendations for inclusion in ACI 318-14 and Eurocode 2, so that a wider adoption of steel fiber **reinforced** **concrete** can be achieved in the construction industry.

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36 deflection response from the **experimental** observation. In general, all five slab specimens that were modeled showed a very strong correlation between the finite element model and the **experimental** **results** (Figure 2-16). The ascending branch followed a very similar line as the **experimental** data and then, at the point of punching **shear**, the FEA curve experienced a very sharp downward trend. The two experiments (N-GR-C slab and L-SH-C slab) shown in Figure 2-16 have **concrete** compressive strengths that varies from 34 MPa to 47 MPa and a flexural reinforcement ratio, ρ, which varies from 0.24% to 0.15%. In developing the **tension**-stiffening curve the author only describes selecting 0.4 for the weakening function (see Equation (2-18)), but neglected to disclose what effect of varying the weakening function would have on the load- deflection **results**. Even though the **concrete** strength and flexural reinforcement varied in the specimens, the weakening function remained constant. The constant value of the weakening function appears to suggest that it is independent of the value of 𝑓 𝑐 ′ and ρ. This assertion would be in contrast to the literature data which showed **tension**-stiffening increases with increases in 𝑓 𝑐 ′ and ρ.

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For these panels, a more ductile response was again found when a 4 inch bedding strip height was used, with over 0.010 radians of **shear** strain experienced at failure compared to less than 0.006 radians for the ½ inch strip specimens. The **shear** load **capacity** was much greater for the C.2 and D.2 panels than their A.1 and B.1 counterparts, due to the more robust design of the embed connection. One particularly interesting observation to be made, however, is that the ultimate capacities remained relatively the same when the bedding strip height was reduced. This illustrated that the additional prying moment created from an increased connection eccentricity had little effect on the panel’s ultimate **capacity**. The slight variation in ultimate strength between strip heights was most likely due to the high variability of **concrete** tensile properties. Despite this minor difference, all panels tested well exceeded the expected design strength. The **results** of the PCP in-plane **shear** tests when considering ultimate load are summarized below in Table 4.2, while calculations used in determining the expected **shear** **capacity** can be found in Appendix A.2.

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