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1
Ninčević, Krešimir, Ioannis Boumakis, Marco Marcon, and Roman Wan-Wendner. "Aggregate effect on concrete cone capacity." Engineering Structures 191 (July 2019): 358–69. http://dx.doi.org/10.1016/j.engstruct.2019.04.028.
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Karmokar, Trijon, Alireza Mohyeddin, and Jessey Lee. "Predictive models for concrete cone capacity of cast-in headed anchors in geopolymer concrete." Engineering Structures 285 (June 2023): 116025. http://dx.doi.org/10.1016/j.engstruct.2023.116025.
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Xu, Xiaoqing, Shanwen Zeng, Wei He, Zhujian Hou, Dongyang He, and Tao Yang. "Numerical Study on the Tensile Performance of Headed Stud Shear Connectors with Head-Sectional Damage." Materials 15, no. 8 (April 11, 2022): 2802. http://dx.doi.org/10.3390/ma15082802.
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An extensive numerical study was carried out due to the concern that head-sectional damage caused by corrosion poses a threat to the tensile performance of headed stud connectors. Three-dimensional finite element models of pull-out tests were established, with both material and geometric nonlinearities being considered. In particular, the concrete weak region due to bleeding was simulated. The simulation method was verified by the results of pull-out tests on two connectors with different damage degrees. Tensile performance of headed stud shear connectors of various shaft diameters (ds = 10 to 25 mm) with various damage degrees (up to 50%) was simulated. It was observed that the connector with a high damage degree exhibited low capacity and a failure closer to pull-out failure than concrete cone breakout failure. Based on the numerical results, reduction factors for quantitatively assessing the influence of head-sectional damage degree on the loading capacity and stiffness of connectors were proposed. With reference to the Concrete Capacity method, the reduction in tensile capacity of connectors with head-sectional damage was found to be caused by the decrease in the projected area of the concrete cone due to the reduction in head diameter, concrete cone angle, and embedment depth. Meanwhile, numerical results showed that the stiffness of a connector at a high embedment depth or in high strength concrete was more sensitive to head-sectional damage. It was also found that the elastic modulus of the weak region significantly affected the stiffness of connectors, while the influence of its thickness on the capacity and stiffness was insignificant.
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Robson, Miora Nirina, Omar Al-Mansouri, Nicolas Pinoteau, Marco Abate, Kenton McBride, Roberto Piccinin, Sébastien Rémond, and Dashnor Hoxha. "Experimental Investigation of the Concrete Cone Failure of Bonded Anchors at Room and High Temperature." Applied Sciences 12, no. 9 (May 9, 2022): 4760. http://dx.doi.org/10.3390/app12094760.
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Under fire conditions, bonded anchors often exhibit pull-out failure due to the thermal sensitivity of polymer-based adhesives. However, progress in manufacturing has allowed the development of more thermoresistant mortars, enhancing the probability of observing concrete-related failure modes at high temperature. For concrete cone failure, Annex D (Informative) to the European Standard EN 1992-4 provides a method to determine the characteristic fire resistance. This method is based on ISO 834-1 fire ratings and on limited experimental data without inclusion of bonded anchors. To remedy these shortcomings, the present contribution aims to provide the first experimental analyses on the concrete cone failure of bonded anchors loaded in tension and exposed to ISO 834-1 fire conditions, as well as heating with a relatively slower rate. The recorded ultimate loads show that the loss of capacity depends on the embedment depth, failure mode and heating scenario. Regarding exposure to ISO 834-1 fire, the 125 mm anchors lost 50% to 60% of their capacity at ambient temperature after 30 min to 75 min of fire exposure. The results highlight that the existing method gives a conservative prediction of the concrete cone capacity at high temperature. However, its accuracy can be improved. Moreover, the obtained crack patterns by the concrete cone breakout failure mode show that the rise in temperature did not significantly affect the geometry of the failure with slow-rate heating. In contrast, the ISO 834-1 fire conditions increased the radius of the failure cone at the exposed surface to up to 5.5 times the embedment depth. However, in any case, the initial slope of the failure surface was not significantly different from its value at ambient temperature.
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Bokor, Boglárka, Máté Tóth, and Akanshu Sharma. "Fasteners in Steel Fiber Reinforced Concrete Subjected to Increased Loading Rates." Fibers 6, no. 4 (December 6, 2018): 93. http://dx.doi.org/10.3390/fib6040093.
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Increased loading rates on fasteners may be caused by high ground accelerations as a consequence of e.g., nuclear explosions, earthquakes or car collisions. It was concluded by Hoehler et al. (2006) that fasteners under rapid loading rates show an increased ultimate resistance in the concrete dominant failure modes or the ultimate resistance is at least as large as under quasi-static loading. Due to the increased demand on using fasteners in steel fiber reinforced concrete (SFRC), it is intended to show how the ultimate concrete cone capacity of fasteners changes under higher than quasi-static loading rate in normal plain concrete (PC) and in SFRC. This paper presents the results of an extensive experimental program carried out on single fasteners loaded in tension in normal plain concrete and in SFRC. The test series were conducted using a servo-hydraulic loading cylinder. The tests were performed in displacement control with a programmed ramp speed of 1, 100, 1000, and 3500 mm/min. This corresponded to calculated initial loading rates ranging between 0.4 and 1600 kN/s. The results of the tension tests clearly show that the rate-dependent behavior of fasteners in SFRC with 30 and 50 kg/m3 hooked-end-type fibers fits well to the previously reported rate-dependent concrete cone behavior in normal plain concrete. Additionally, a positive influence of the fibers on the concrete cone capacity is clearly visible.
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Nilforoush, Rasoul. "A Refined Model for Predicting Concrete-Related Failure Load of Tension Loaded Cast-in-Place Headed Anchors in Uncracked Concrete." Nordic Concrete Research 60, no. 1 (June 1, 2019): 105–29. http://dx.doi.org/10.2478/ncr-2019-0091.
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Abstract Current theoretical models for predicting the concrete cone breakout capacity of tension loaded headed anchors do not consider the influence of member thickness, size of anchor head, and orthogonal surface reinforcement. In the present study, the influence of the aforementioned parameters was studied both numerically and experimentally. Both the numerical and experimental results showed that the tensile resistance of headed anchors increases by increasing the member thickness or if orthogonal surface reinforcement is present. In addition, the anchorage capacity further increases with increase of the anchor head size. The current model for predicting the concrete cone failure load of tension loaded headed anchors were refined and extended by incorporating three modification factors to account for the influence of the member thickness, size of anchor head, and orthogonal surface reinforcement. The accuracy of the proposed model was verified based on the results of 124 tests on single headed anchors from literature.
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Xie, Qun, Qin Zhu Sheng, and Hao Xue Ju. "Multiple Anchor Behavior of Steel-to-Concrete Connections under Reversed Cyclic Loading." Advanced Materials Research 255-260 (May 2011): 669–73. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.669.
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Four steel-to-concrete connections with adhesive anchor groups under reversed cyclic loading have been tested. The results showed that anchor steel could reach yield strength before connection failure, generating small shell-shaped concrete cone in the surface of block and the ultimate capacity was governed by strength of anchor. Seismic characteristics of hysteresis curve, rigidity regression, ductility and energy-dissipation were used to draw conclusions that the connections would behave in a ductile manner without significant loss of loading capacity after peak value and visible deformation could develop until failure occurred. Increased embedment depth and added amount of anchors were helpful to improve seismic performance of connections. Only the outer row of most stressed anchors in the tension zone were needed to meet the elliptical interaction of tension and shear capacity requirement during the design process of anchor groups under combined shear and moment loading. In seismic design of steel-to-concrete connections, the predicted capacity by a reduction factor of 0.8 was advised and the comparison of calculated versus observed capacity presented limited variance.
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Li, Shanshan, Yukun Zhang, and Dayong Li. "Capacity of Cone-Shaped Hollow Flexible Reinforced Concrete Foundation (CHFRF) in Sand under Horizontal Loading." Advances in Materials Science and Engineering 2020 (October 7, 2020): 1–14. http://dx.doi.org/10.1155/2020/6346590.
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The cone-shaped hollow flexible reinforced concrete foundation (CHFRF) is an innovative type of mountain wind turbine foundation, which outperforms the regular mountain wind turbine foundation in reducing the steel and concrete and protecting the surrounding vegetation for the cavity absorbs soil obtained from excavating the foundation pit. Moreover, the rubber layer installed between the wall of CHFRF and the surrounding ground increases foundation flexibility and releases the larger overturning moment induced by wind. The rubber layer is made of alternately laminated rubber and steel. The objectives of this research are to study the lateral bearing behaviors of the CHFRF under monotonic and cyclic lateral loading in sand by model tests and FEM simulations. The results reveal that the CHFRF rotates during loading; and, in the ultimate state, the rotation center is located at a depth of approximately 0.6–0.65 times the foundation height and is 0.15–0.18 times the diameter of the foundation away from its centerline as well. The lateral bearing capacity of the CHFRF improves with the increase of embedded depth and vertical load applied to the foundation. Moreover, compared to the CHFRF without the rubber layer, the rubber layer can reduce the earth pressure along the wall of CHFRF by 22% and decrease the deformed range of the soil surrounding the foundation, revealing that it can reduce the loads transferred to the surrounding soil for extending the service life of the foundation. However, the thickness and stiffness of the rubber layer are important factors influencing the lateral bearing capacity and the energy dissipation of the foundation. Moreover, it should be noted that the energy dissipation mainly comes from the steel of the rubber layer rather than rubber.
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Podhorecki, Adam, Oleksandr Hnatiuk, Mykola Lapchuk, and Oleksandr Mazepa. "Investigation of Bearing Capacity of the Drill-Impact Micropiles with Enlarged Toe in the Soils of Different Type." IOP Conference Series: Materials Science and Engineering 1203, no. 3 (November 1, 2021): 032054. http://dx.doi.org/10.1088/1757-899x/1203/3/032054.
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Abstract The reinforced concrete micropiles with enlarged toe is the effective construction for the arranging of new and reinforcing of existing foundations which a drill-impact method are made as a circular bar with a diameter to 250 mm from the flow consistency concrete with prefabricated reinforcement cage and enlarged to two diameters toe cone-shaped form. For research of them real work by the authors of the article and engineers of PP BKF “Osnova” were conducted them field tests on the objects of building in the different soil conditions and the analysis of them calculation and experimental bearing capacity is given. The analysis of quantitative correlation of experimental and theoretical bearing capacity for the different types of soils is the task of researches.
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Wen, Yang. "The Study on Force Behavior of Concrete Filled Steel Tube Lattice Wind Turbine Tower with Three Limb Columns." Applied Mechanics and Materials 178-181 (May 2012): 179–83. http://dx.doi.org/10.4028/www.scientific.net/amm.178-181.179.
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This paper refers to currently the 1.5MW cone tube type wind-driven generator tower, design the model of the concrete-filled steel tube wind turbine tower with three limb columns, and research on the force performance, such as the change of internal force, the process of failure, hysteretic behavior, bearing capacity, ductility and energy dissipation capacity by the pseudo-static experiment on the scale model of wind turbine tower. The study shows that the P- hysteretic curve of lattice concrete-filled steel tube wind-driven generator tower with three limb columns is asymmetric, relatively full “spindle” and the phenomenon of “knead shrink” is not obvious, which account for it has good force behavior and energy dissipation capacity. This kind of tower structure, of which the reverse bearing capacity is greater than the positive, and the reverse ductility coefficient is less than the positive, indicates that it’s reverse plastic deformation ability of the tower structure is weaker than it’s positive.
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Arslan, Guray, and Melih Hacisalihoglu. "NONLINEAR ANALYSIS OF RC COLUMNS USING THE DRUCKER-PRAGER MODEL." Journal of Civil Engineering and Management 19, no. 1 (January 16, 2013): 69–77. http://dx.doi.org/10.3846/13923730.2012.734858.
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This paper aims to investigate the correct prediction of load carrying capacity of reinforced concrete (RC) columns. Although substantial experimental and analytical researches have been conducted to model and simulate the response of concrete, little success has been achieved for the general description of the failures of RC columns subjected to bending and axial load. In order to predict the load carrying capacity of RC column, this paper introduces a new relationship for calculating the cohesion parameter of Drucker-Prager criterion. The relationship is developed from a parametric study of a large number of nonlinear finite element analyses of RC columns to account for the parameters. Incorporating these parameters into the failure criterion of concrete, the failure cone of Drucker-Prager model is enforced to approximate and coincide with the whole compressive meridian of the criterion up to the analytically predicted point of the load carrying capacity in the failure analyses. The proposed approach is compared with other approaches using the available column test data to demonstrate how accurately it predicts the load carrying capacity. It is shown that the proposed approach fit quite well to the experimental results of 28 specimens tested by four different researchers.
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Spyridis, Panagiotis, and Oladimeji B. Olalusi. "Predictive Modelling for Concrete Failure at Anchorages Using Machine Learning Techniques." Materials 14, no. 1 (December 25, 2020): 62. http://dx.doi.org/10.3390/ma14010062.
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Anchorage to concrete plays a significant role in various aspects of modern construction. The structural performance of anchors under direct tensile load can lead to failure by concrete cone breakout. Concrete related failure modes are quasi-brittle, and as such, they may develop without prior warning indications of damage, while it also exposes the bearing component to damage propagation. As such, an adequate reliability assessment of anchors against concrete cone failure is of high importance, and improved precision and minimisation of uncertainty in the predictive model are critical. This contribution develops predictive models for the tensile breakout capacity of fastening systems in concrete using the Gaussian Process Regression (GPR) and the Support Vector Regression (SVR) machine learning (ML) algorithms. The models were developed utilising a set of 864 experimental anchor tests. The efficiency of the developed models is assessed by statistical comparison to the state-of-practice semi-empirical predictive model, which is embedded in international design standards. Furthermore, the algorithms were evaluated based on a newly introduced Model Explainability concept based on Analogous Rational and Mechanical phenomena (MEARM). Finally, a discussion is provided regarding the developed ML models’ suitability for use as General Probabilistic Models in a reliability framework.
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Ahmad, Jawad, Fahid Aslam, Rebeca Martínez-García, Jesús de Prado-Gil, Nadeem Abbas, and Mohamed Hechmi EI Ouni. "Mechanical performance of concrete reinforced with polypropylene fibers (PPFs)." Journal of Engineered Fibers and Fabrics 16 (January 2021): 155892502110603. http://dx.doi.org/10.1177/15589250211060399.
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Fibers are one of the most prevalent methods to enhance the tensile capacity of concrete. Most researchers focus on steel fiber reinforced concrete which is costly and easily corroded. This study aims to examine the performance of polypropylene fiber reinforced concrete through different tests. PPFs were added into concrete blends in a percentage of 1.0%, 2.0%, 3.0%, and 4.0% by weight of cement to offset its objectionable brittle nature and improve its tensile capacity. The fresh property was evaluated through slump cone test and while mechanical strength was evaluated through compressive strength, split tensile strength flexure strength, and flexure cracking behaviors after 7-, 14-, and 28-days curing. Results indicate that slump decrease with the addition of PPFs while fresh density increase up to 2.0% in addition to PPFs and then decreases. Similarly, strength (compressive strength; split tensile strength, and flexure strength) was increased up to 2.0% addition of PPFs and then decrease gradually. It also suggests that Ductility; first crack load, maximum crack width, and load-deflection inter-relations were considerably improved due to incorporations of PPFs.
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Marcon, Marco, Krešimir Ninčević, Ioannis Boumakis, Lisa-Marie Czernuschka, and Roman Wan-Wendner. "Aggregate Effect on the Concrete Cone Capacity of an Undercut Anchor under Quasi-Static Tensile Load." Materials 11, no. 5 (May 1, 2018): 711. http://dx.doi.org/10.3390/ma11050711.
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Duan, Ning, and Jiwen Zhang. "Comparison of Punching Shear Behaviour of Two-Way Concrete Slab Reinforced with CFRP Grid and Steel Bars." Journal of Physics: Conference Series 2463, no. 1 (March 1, 2023): 012013. http://dx.doi.org/10.1088/1742-6596/2463/1/012013.
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Abstract Two punching shear failure tests of two-way concrete slab reinforced by CFRP grid and HRB 400 steel were studied in this paper. The reinforcement ratio of slab reinforced with CFRP grid and HRB400 is 0.33% and 0.37 respectively. The upper and lower surfaces of the concrete slab’s tensile and compressive strains, the reinforcement strains, the load deflection of the slabs, and the applied load value were analyzed. The results show that under approximately the same reinforcement ratio, the concrete slab reinforced with CFRP grid has higher bearing capacity. Both slab failure formed with punching cones, the punching cone angle of CFRP grid slab is 24.1°, which is far less than 38° for reinforced concrete slabs. The tests results indicated that there is a cooperative between longitudinal and transverse limb of CFRP grid.
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Kuzhakhmetova, Elvira R. "Influence of constructive solutions on the stiffness characteristics of the rammed monolithic reinforced concrete cone-shaped piles with side and bottom forms from crushed stones." Structural Mechanics of Engineering Constructions and Buildings 17, no. 5 (December 30, 2021): 500–518. http://dx.doi.org/10.22363/1815-5235-2021-17-5-500-518.
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Relevance. The article discusses the design solutions of a new pile structure, which is a monolithic reinforced concrete cone-shaped pile, enclosed in a crushed stone shell and resting on a spherical crushed stone broadening. In the course of a numerical study, carried out using the finite element method, the influence of the geometric parameters of the crushed stone formations of the pile foundation, such as the wall thickness of the crushed stone shell and the radius of the crushed stone broadening, on its bearing capacity was revealed. The aim of the study is to perform a comparative numerical analysis of the stressstrain state of a pile structure with different design solutions, operating as part of a soil massif. Materials and methods. Numerical static analysis of the structure of a monolithic reinforced concrete pile foundation operating in a soil massif was carried out using a spatial finite element model in the CAE-class software package. The article presents the results of a numerical analysis of the stress-strain state of a rammed monolithic reinforced concrete cone-shaped pile with different wall thicknesses of the crushed stone shell and different diameters of the lower spherical crushed stone broadening. The analysis showed that changes in the specified geometric parameters of the pile foundation have a significant impact on its bearing capacity under external forces. The rational choice of these parameters allows you to economically use the concrete mixture and reinforcing rods intended for the manufacture of monolithic reinforced concrete rammed piles, which, in turn, leads to a decrease in financial costs for the manufacture of the pile foundation and the entire building as a whole. The next research is supposed to carry out a comparative analysis of the numerical results with experimental data obtained in laboratory and field conditions.
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Sonoda, Yoshimi. "A Numerical Study on the Pull-Out Strengths of Anchor Bolts Embedded in Concrete Using the Smoothed Particle Hydrodynamics Method." Key Engineering Materials 711 (September 2016): 1111–17. http://dx.doi.org/10.4028/www.scientific.net/kem.711.1111.
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The strength of an anchor bolt in concrete structure under pull-out load is usually designed by three possible failure modes such as fracture of anchor bolt, cone failure of concrete and bond failure between anchor bolt and concrete. In general, the design load is considered the smallest load corresponding to the aforementioned failure mechanisms. However, unexpected failure often occurs in the anchorage zone due to the complex failure or the change of failure condition. Therefore, it is important to develop the accurate analysis method of ultimate load bearing capacity of the anchor bolt. In this study, we conducted an analytical study using Adaptive Smoothed Particle Hydrodynamics (ASPH) in order to simulate the failure process of anchorage zone and discussed the effect of embedment depth of anchor bolts on their ultimate strength.
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Jonak, Józef, Robert Karpiński, Michał Siegmund, Andrzej Wójcik, and Kamil Jonak. "Analysis of the Rock Failure Cone Size Relative to the Group Effect from a Triangular Anchorage System." Materials 13, no. 20 (October 19, 2020): 4657. http://dx.doi.org/10.3390/ma13204657.
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This study employs the numerical analysis and experimental testing to analyze the fracturing mechanics and the size of rock cones formed in the pull-out of a system of three undercut anchors. The research sets out to broaden the knowledge regarding: (a) the potential of the undercut anchor pull-out process in mining of the rock mass, and (b) estimating the load-carrying capacity of anchors embedded in the rock mass (which is distinctly different from the anchorage to concrete). Undercut anchors are most commonly applied as fasteners of steel components in concrete structures. The new application for undercut anchors postulated in this paper is their use in rock mining in exceptional conditions, such as during mining rescue operations, which for safety considerations may exclude mechanical mining techniques, mining machines, or explosives. The remaining solution is manual rock fracture, whose effectiveness is hard to assess. The key issue in the analyzed aspect is the rock fracture mechanics, which requires in-depth consideration that could provide the assistance in predicting the breakout prism dimensions and the load-displacement behavior of specific anchorage systems, embedment depth, and rock strength parameters. The volume of rock breakout prisms is an interesting factor to study as it is critical to energy consumption and, ultimately, the efficiency of the process. Our investigations are supported by the FEM (Finite Element Method) analysis, and the developed models have been validated by the results from experimental testing performed in a sandstone mine. The findings presented here illuminate the discrepancies between the current technology, test results, and standards that favor anchorage to concrete, particularly in the light of a distinct lack of scientific and industry documentation describing the anchorage systems’ interaction with rock materials, which exhibit high heterogeneity of the internal structure or bedding. The Concrete Capacity Design (CCD) method approximates that the maximum projected radius of the breakout cone on the free surface of concrete corresponds to the length of at the most three embedment depths (hef). In rock, the dimensions of the breakout prism are found to exceed the CCD recommendations by 20–33%. The numerical computations have demonstrated that, for the nominal breakout prism angle of approx. 35% (CCD), the critical spacing for which the anchor group effect occurs is ~4.5 (a cross-section through two anchor axes). On average, the observed spacing values were in the range of 3.6–4.0.
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Li, Bin, Zhong Zhou Han, and Chun Yan Gao. "Experiment Research on Mechanical Behavior for Latticed Concrete-Filled Steel Tubular Tower with Three Limbs." Advanced Materials Research 368-373 (October 2011): 58–61. http://dx.doi.org/10.4028/www.scientific.net/amr.368-373.58.
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Based on the 1.5MW cone cylinder wind turbine tower widely used at present, latticed concrete-filled steel tubular (CFST) tower with three limbs was designed. The stress mechanism and failure process, hysteretic properties, bearing capacity and energy dissipation capacity were studied by quasi-static test on the tower model. The results indicate that the hysteretic loops of the latticed CFST tower with three limbs present asymmetrical plump “spindle” and there is no obvious "pinch" phenomenon, which shows good seismic performance and energy dissipation capacity; and that owing to the latticed CFST tower with three limbs is asymmetric along the centroidal axis perpendicular to loading direction, plastic hinge finally appeared in the tower column foot which beared the largest force, the bottom web members were buckled and occur unstable failure. From the analysis it can be seen that the latticed CFST tower structure with three limbs has value of further research and promotion.
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Bol, Ertan, and Zeynep Süreyya Genç. "Pile Capacity Calculation by using SPT and CPT Data." Academic Perspective Procedia 2, no. 3 (November 22, 2019): 1377–87. http://dx.doi.org/10.33793/acperpro.02.03.153.
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In this paper, a study has been carried out to estimate the ultimate capacities of concrete circular piles which are used as foundation type due to reasons such as poor ground conditions, seismicity, high or irregular loads etc. by field tests. Two cone penetration tests (CPTU), which measure the pore water pressures on alluvial soils of the Adapazarı plain, were conducted at the same locations with drillings which SPT tests were carried out. Ultimate capacities of a single pile with a specific geometry were determined by the methods proposed in the literature by using the data obtained from SPT and CPT field tests at both points. According to this, it is concluded that pile capacities can give very different results even in short distances in regions which offer sudden layer changes in horizontal and vertical. Disadvantages of the SPT test in practice compared to CPT have been shown to cause also different values of pile capacities.
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Mutiara, Indra. "Analysis of Bored Pile Foundation Bearing Capacity Based on Cone Penetration Test Data (Case Study: Cilellang Weir Location)." INTEK: Jurnal Penelitian 8, no. 1 (July 25, 2021): 30. http://dx.doi.org/10.31963/intek.v8i1.2772.
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The use of a bored pile foundation is an alternative in planning deep foundations. The function of this bored pile foundation is more or less the same as other deep foundations such as piles but has a slight difference in the process. The bored pile foundation begins with drilling the ground to the planned depth, followed by the installation of steel reinforcement and then concrete mortar. This study aims to evaluate the Cone Penetration Test (CPT) data on the bearing capacity of the bored pile foundation. Calculation of bearing capacity from Cone Penetration Test (CPT) data using the Schmertmann & Nottingham method and the Mayerhof method. Based on CPT data, the percentage calculation of ultimate bearing capacity at location S1 with the Schmertmann & Nottingham method is more optimistic ±17.28% compared to using the Mayerhof method for bored pile diameters of 60 and 80 cm, while for bored pile diameters of 40 cm, calculations using the Mayerhof method show more optimistic by 21.89%. The percentage calculation of ultimate bearing capacity at location S2 using the Schmertmann & Nottingham method is ±11.66% more optimistic than using the Mayerhof method for bored pile diameters of 60 and 80 cm, while the diameter of the bored pile 40 cm, the calculation using the Mayerhof method shows a more optimistic result of 33.82%.
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Fauzan, Nadia Milla Hanifah, Willy Peratundhika E, Mutia Putri Monika, and Zev Al Jauhari. "Structural evaluation of 3-story dormitory reinforced concrete building considering soil liquefaction potential." E3S Web of Conferences 156 (2020): 05015. http://dx.doi.org/10.1051/e3sconf/202015605015.
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The liquefaction phenomenon is the increase in water pressure in the soil, which will reduce the soil strength in supporting the load and loss of binding power between its grains. Soil liquefaction usually occurs when there is a seismic movement in the soil layer due to seismic (earthquakes) loads. Therefore, the building constructed in the soil liquefaction prone area should be designed according to the standard code. However, many design consultants do not pay attention to this condition and the building still was designed as usual even the building is located on soil liquefaction prone area. In 2018, a 3-story dormitory building structure of Hamka’s boarding school was constructed on soil liquefaction prone area in Padang city. After reviewing the design document, it was found that the consultant did not consider the soil liquefaction in its structural analysis. In this study, an evaluation of the building structure was carried out to investigate the capacity of the building in resisting the loads. From the soil evaluation using the soil Cone Penetration Test (CPT) result, it was found that the location of the dormitory building has a liquefaction potential at a depth of 1.2 - 8 meters. Considering the soil liquefaction potential in the building, the structural analysis results show that the capacity of the dormitory building, especially column, beam and foundation were not strong enough to resist the combination loads acting on the structures. Therefore, the building structure should be strengthened to face the further big earthquake that will cause the soil liquefaction.
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Sabri, Mohanad, Aleksandr Bugrov, Stanislav Panov, and Viacheslav Davidenko. "Ground improvement using an expandable polyurethane resin." MATEC Web of Conferences 245 (2018): 01004. http://dx.doi.org/10.1051/matecconf/201824501004.
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The paper describes an experiment conducted to study the effect of injection an expandablepolyurethane resin on the stabilization, settlement reduction and increasing the bearing capacity of the foundation’s soil. The experiment was carried out in sandy soil, and different types of soil investigations were carried out to investigate the effect of the resin on the soil properties beneath a concrete foundation. Results of Plate load test PLT and dynamic cone penetration test DCPT before and after the injection of the expandable resin are demonstrated and discussed in this paper.
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Abu-Farsakh, Murad Y., Mohsen Amirmojahedi, and George Z. Voyiadjis. "Development of Combined Pile-CPT Methods for Estimating the Ultimate Axial Capacity of PPC Piles Driven in Different Soil Categories in Louisiana." Transportation Research Record: Journal of the Transportation Research Board 2674, no. 2 (February 2020): 313–27. http://dx.doi.org/10.1177/0361198120907325.
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The cone and piezocone penetration tests (CPT, PCPT) have been widely acknowledged as useful in-situ testing tools for subsurface investigation, characterization of soil type, and evaluation of different soil properties. Because of similarity between the cone and pile, the evaluation of axial pile capacity was one of initial applications of the CPT/PCPT. A previous study conducted by the authors on 80 pile load tests of precast prestressed concrete (PPC) piles demonstrated that some pile-CPT methods are able to predict the ultimate axial pile capacity with better accuracy than other methods. These methods include: Schmertmann, De Ruiter and Beringen, Laboratoire Central des Ponts et Chaussées (LCPC), European Regional Technical Committee 3 (ERTC3), University of Western Australia (UWA), probabilistic, and University of Florida (UF) methods. The results of these seven pile-CPT methods were compared and their performance was examined for different soil categories where different percentages of pile capacity contribution is because of sandy layers. The log-normal distribution of the estimated to measured pile capacity for these pile-CPT methods was adopted to develop combined pile-CPT methods that optimize the estimation accuracy of axial pile capacity in different soil categories. Reliability analysis using Monte Carlo Simulation (MCS) was used to evaluate the resistance factors ( ϕ) and efficiency ( ϕ/ λR) of the individual and combined pile-CPT methods. Results of analysis of 80 pile load tests demonstrated the advantage of using the combined pile-CPT methods over the individual methods in relation to improving the accuracy of estimating the ultimate axial pile capacity and having better resistance factors.
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Kabantsev, Oleg, and Mikhail Kovalev. "Failure Mechanisms and Parameters of Elastoplastic Deformations of Anchorage in a Damaged Concrete Base under Seismic Loading." Buildings 12, no. 1 (January 13, 2022): 78. http://dx.doi.org/10.3390/buildings12010078.
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The article addresses mechanisms of anchorage failure in a concrete base studied within the framework of physical experiments. The authors investigated the most frequently used types of anchors, such as the cast-in-place and post-installed ones. The anchorages were studied under static and dynamic loading, similar to the seismic type. During the experiments, the post-earthquake condition of a concrete base was simulated. Within the framework of the study, the authors modified the values of such parameters, such as the anchor embedment depth, anchor steel strength, base concrete class, and base crack width. As a result of the experimental studies, the authors identified all possible failure mechanisms for versatile types of anchorages, including steel and concrete cone failures, anchor slippage at the interface with the base concrete (two types of failure mechanisms were identified), as well as the failure involving the slippage of the adhesive composition at the interface with the concrete of the anchor embedment area. The data obtained by the authors encompasses total displacements in the elastic and plastic phases of deformation, values of the bearing capacity for each type of anchorage, values of the bearing capacity reduction, and displacements following multi-cyclic loading compared to static loading. As a result of the research, the authors identified two types of patterns that anchorages follow approaching the limit state: elastic-brittle and elastoplastic mechanisms. The findings of the experimental research allowed the authors to determine the plasticity coefficients for the studied types of anchors and different failure mechanisms. The research findings can be used to justify seismic load reduction factors to be further used in the seismic design of anchorages.
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Kwon, Minho, Jinsup Kim, Hyunsu Seo, and Wooyoung Jung. "Long-term performance of mechanically post-installed anchor systems." Advances in Structural Engineering 20, no. 3 (July 28, 2016): 288–98. http://dx.doi.org/10.1177/1369433216649396.
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A mechanically post-installed anchor, which is one of the most widely used post-installed anchors in South Korea, was selected to evaluate long-term usage through a pullout test. Two types of specimens were constructed: the original specimens and freeze and thaw specimens. Mechanically post-installed anchors were installed in both of them. A freeze and thaw test method was utilized to consider the long-term usage. The compressive strength of concrete during the freeze and thaw test method is reduced by about 20% compared to that of the original concrete. From the pullout test results, the pullout strength of the freeze and thaw specimen was smaller by about 50% than that of the original specimens. Furthermore, the failure mode of the freeze and thaw specimens was changed. Cone shape destruction of anchors and anchor pullout destruction occurred in the original specimens; concrete pullout destruction occurred dominantly in the freeze and thaw specimens. Based on the comparison results, the reduction factor ( λ) for long-term usage of the mechanically post-installed anchor was derived using a probability function and was proposed to modify the concrete capacity design equation.
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Mellati, Afshin. "Predicting Dynamic Capacity Curve of Elevated Water Tanks: A Pushover Procedure." Civil Engineering Journal 4, no. 11 (November 29, 2018): 2513. http://dx.doi.org/10.28991/cej-03091177.
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Despite the importance of water tanks for water supplies and supporting the community resilience through the firefighting usages in catastrophic conditions, post-earthquake situations especially, a few studies have been done on seismic behavior of water tanks so far. The scope of this paper is to propose a new pushover procedure to evaluate seismic responses of elevated water tanks (EWT) supported on the concrete shaft in the form of dynamic capacity curves (i.e. base shear versus top displacement). In this regard, a series of shaft supported EWTs are simulated considering soil-structure and fluid-structure interactions. The shaft is modelled with frame elements and plastic hinges are assigned along the shaft to consider the material nonlinearity. The effect of soil-structure interaction and fluid-structure interaction are considered through the well-known Cone model and modified Housner model, respectively. At first, parametric studies have been conducted to investigate the effects of various essential parameters such as soil type, water level and tank capacity on seismic responses of EWTs using incremental dynamic analysis (i.e. nonlinear-time-history-analyses with varying intensities). Thereafter, pushover analyses as nonlinear static analyses are performed by variation of lateral load patterns. Finally, utilizing these results and comparing them with mean IDA curve, as an exact solution; a pushover procedure based on the most reliable lateral load patterns is proposed to predict the mean IDA curve of the EWTs supported on the concrete shaft. The obtained results demonstrate the accuracy of the proposed pushover procedure with errors limited to 30 % only in the changing stage from linear to nonlinear sections of the IDA curve.
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Dragomirová, Janette, and Martin Palou. "Verification of the Physical and Mechanical Properties of the Heavyweight Concrete Used in the Shielding Construction of Reactor Casing at the Nuclear Power Plant." Materials Science Forum 1070 (October 13, 2022): 223–29. http://dx.doi.org/10.4028/p-4nulnu.
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The present paper deals with the determination of the mechanical and physical properties of the heavyweight concrete formulation used in the shielding construction of the reactor casing power plant. The recipe includes the use of baryte and cast-iron crumbs as fillers for the preparation of heavyweight concrete. The binder paste was obtained using CEM I 42.5 R with w/c ratio = 0.44 and a lignosulfonate-based plasticizer prepared according to the used Ralentol plasticizer's standard requirements, which is currently no more produced. The result of the concrete slump according to the S -cone was S1 (1 cm slump). The bulk density of fresh and hardened concrete was over 4000 kg m-3. The compressive strength at 28 days exceeds 80 N mm-2 and the flexural strength is 4 N mm-2. The modulus of elasticity is 40 GN m-2. The shrinkage of concrete is 0.52 ‰. The weight loss due to shrinkage rises to almost 1.3 %. The thermal properties of the heavyweight concrete are as follows: the thermal conductivity λ is 2.2 W m-1 K-1; the thermal resistance R for thickness d = 1 m is 0.44 m2 K W-1; volume heat capacity cρ rises to almost 2 J m-3 K-1 and thermal diffusivity a 10-6 drops to 1,15 m2 s-1.
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Wei, Yingjie, Duli Wang, Jiawang Li, Yuxin Jie, Zundong Ke, Jianguang Li, and Tsunming Wong. "Evaluation of Ultimate Bearing Capacity of Pre-Stressed High-Strength Concrete Pipe Pile Embedded in Saturated Sandy Soil Based on In-Situ Test." Applied Sciences 10, no. 18 (September 9, 2020): 6269. http://dx.doi.org/10.3390/app10186269.
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Estimation of ultimate bearing capacity (UBC) of pre-stressed high-strength concrete (PHC) pipe pile is critical for optimizing pile design and construction. In this study, a standard penetration test (SPT), static cone penetration test (CPT) and static load test (SLT) were carried out to assess, determine and compare the UBC of the PHC pipe pile embedded in saturated sandy layers at different depths. The UBC was calculated with three methods including the JGJ94-2008 method, Meyerhof method and Schmertmann method based on in-situ blow count (N) of SPT (SPT-N) which was higher than the values recommended in survey report regardless of pile length. The average UBC values calculated with cone-tip resistance and sleeve friction from CPTs was also higher than the value recommended in the survey report. Moreover, the actual UBC values directly obtained by load-displacement curves from SLTs were in line with the calculated values based on in-situ SPTs and CPTs, but approximately twice as high as the values recommended in the survey report regardless of pile length. For the SPT method, the application of bentonite mud in saturated sand layers is critical for the assessment of pile capacity in the survey phase, CPTs can provide reliable results regardless of soil characteristics and groundwater if the soil layer can be penetrated, and SLTs are necessary to accurately determine the UBC in complex stratum.
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Amirmojahedi, Mohsen, and Murad Abu-Farsakh. "Evaluation of 18 Direct CPT Methods for Estimating the Ultimate Pile Capacity of Driven Piles." Transportation Research Record: Journal of the Transportation Research Board 2673, no. 9 (May 4, 2019): 127–41. http://dx.doi.org/10.1177/0361198119833365.
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Cone and piezocone penetration tests (CPT, PCPT) are widely acknowledged to be useful and powerful in-situ tests for soil classification and characterization, and for evaluating different soil properties, such as strength and consolidation parameters. Due to similarity, between the cone and the pile penetration, CPT data have been used effectively for estimating ultimate pile capacity. Researchers have developed various direct CPT methods to estimate the ultimate capacity of piles ( Qp) from CPT/PCPT data (tip resistance and sleeve friction) with depth. In this study, the measured ultimate pile capacities ( Qp) obtained from static load tests on 80 square precast prestressed concrete piles in Louisiana were used to evaluate 18 direct pile-CPT methods for estimating ultimate pile capacity. Two approaches were used. In the first approach, three criteria (best fit line, arithmetic mean and standard deviation, and cumulative probability of Qp/Qm) were adopted, and the sum of ranking of all criteria was used to determine the final ranking of each method. A second approach, multidimensional unfolding, was used to display the ranking data in a two-dimensional space. This approach helps to reveal the typical ranking of the pile-CPT methods, the extent of agreement between the piles, the existence of outliers among the piles, and the similarity between the CPT methods. Based on the results of this study, Bustamante and Gianeselli (LCPC), probabilistic, UF, Philipponnat, CPT2000, UWA, De Ruiter and Beringen, and Schmertmann were found to be the best CPT methods (in order) for estimating the ultimate pile capacity of driven PPC piles.
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Tun, Zin Zin, Anat Ruangrassamee, and Qudeer Hussain. "Mitigation of Tsunami Debris Impact on Reinforced Concrete Buildings by Fender Structures." Buildings 12, no. 1 (January 10, 2022): 66. http://dx.doi.org/10.3390/buildings12010066.
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Buildings located in coastal regions are prone to tsunami dangers, which often carry debris in the form of shipping containers and boats. This paper presents an approach for the design of fender structures to minimize debris impacts on buildings. The impact of shipping containers, which are categorized as large debris, is considered in the study. Since the weights of shipping containers are standardized, the impact energy can be related to other debris. For a fender structure, cone-type rubber fenders are used to resist the impact of the shipping container. Various fender reactions are considered as parameters to study the efficiency of the fenders. The displacement-controlled nonlinear static analysis is carried out to determine the building capacity. The energy approach for shipping container impact is used to evaluate the resistance of the building. Capacity curves, energy absorptions, inter-story drift ratios of the buildings with and without a fender structure, and the efficiency of the fender are presented. The buildings with a fender structure can absorb the energy from the impact of a loaded shipping container. Conversely, the building without a fender structure cannot resist the impact of a loaded shipping container. From the obtained results, a recommendation is given for buildings with a fender structure. The hydrodynamic force on the fender structure is transferred to the main building through the fender. Hence, the yield force of the fenders affects the performance of the main building that must be considered in the design.
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Leung, Christopher K. Y., Angus K. F. Cheung, and Xiu Fang Zhang. "Partial Use of Pseudo-Ductile Cementitious Composites in Concrete Components to Resist Concentrated Stress." Key Engineering Materials 312 (June 2006): 319–24. http://dx.doi.org/10.4028/www.scientific.net/kem.312.319.
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The high pseudo-ductility of Engineered Cementitious Composites (ECC) makes it a particularly effective material to resist the propagation of cracks. In applications where failure is due to cracking initiated by localized stresses, the application of ECC around the stress concentrated region should result in significant improvement in the ultimate failure load. In this investigation, we will study the use of ECC in (i) the anchorage zone of post-tensioned concrete members, and (ii) the region around embedded anchor bolts in concrete blocks. For the first application, the replacement of concrete with ECC at the anchorage zone is found to be very effective in increasing the load capacity under concentrated compression. Based on our test results, ECC can actually replace all or part of the conventional steel stirrups in resisting splitting failure at the anchorage zone. For embedded anchor bolts, the placement of a small ECC disc above the steel bolt can effectively delay the propagation of cone-shape failure and increase the pull-out force. Through the present experimental program, we have illustrated the advantage of strategically applying ECC in critical region of structural components, to improve performance without significant increasing the material cost.
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Kuzhakhmetova, Elvira R. "Research of stress-deformed state of the rammed monolithic reinforced concrete cone-shaped piles with side and bottom forms from crushed stones." Structural Mechanics of Engineering Constructions and Buildings 17, no. 4 (December 15, 2021): 335–56. http://dx.doi.org/10.22363/1815-5235-2021-17-4-335-356.
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Relevance. In the construction of buildings and structures, driven piles with a square cross section are most widely used. To install them in the working position, the percussion method is used. However, in cramped conditions, shock loads can lead to dangerous conditions and destruction of structures of nearby buildings. In such a situation, it is necessary to use rammed piles, since technological solutions for their construction are not associated with shock effects on the soil. One such solution is the new rammed cone-shaped pile design, which is installed without excavation. The aim of the study is to analyze the influence of the geometric parameters of the pile on its bearing capacity under the action of external loads, in particular, the angle of its taper. Methods. The results of a numerical analysis of the stress-strain state of a pile operating in a soil massif were obtained by the finite element method. Results. In the computational study, a comparative analysis of the state of piles of different lengths and geometries under the action of external loads was carried out. The influence of the angle of inclination of the lateral surface of the pile on its bearing capacity is considered. Rationalization of the pile design was carried out taking into account the total costs of building materials. Variants of geometric and design solutions for piles with a length L from 1 to 10 m are proposed. In subsequent articles, it is proposed to consider the effect on the bearing capacity of the pile of the geometric parameters of the crushed stone shell and the lower crushed stone spherical expansion, as well as to carry out a comparative analysis of the numerical results with experimental data obtained in laboratory and field conditions.
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Olson, Scott M., Russell A. Green, Samuel Lasley, Nathaniel Martin, Brady R. Cox, Ellen Rathje, Jeff Bachhuber, and James French. "Documenting Liquefaction and Lateral Spreading Triggered by the 12 January 2010 Haiti Earthquake." Earthquake Spectra 27, no. 1_suppl1 (October 2011): 93–116. http://dx.doi.org/10.1193/1.3639270.
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The 12 January 2010 Haiti earthquake (Mw 7.0) caused extensive damage to the Port-au-Prince region, including severe liquefaction failures along the Gulf of Gonâve coastline, along rivers north of Port-au-Prince draining into the Gulf, and a liquefaction-induced structural/bearing capacity failure of a three-story concrete hotel along the southern coast of the Gulf. During two reconnaissance missions, the authors documented ground conditions and performance at eight sites that liquefied and two sites that did not liquefy. Geotechnical characterization included surface mapping, dynamic cone penetration tests, hand auger borings, and laboratory index tests. The authors estimated median peak ground accelerations (PGAs) of approximately 0.17g to 0.48g at these sites using the Next Generation Attenuation (NGA) relations summarized by Power et. al. (2008) . These case histories are documented here so that they can be used to augment databases of level-ground/near level-ground liquefaction, lateral spreading, liquefaction flow failure, and liquefaction-induced bearing capacity failure.
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Lu, Chi, and Yoshimi Sonoda. "An Analytical Study on the Pull-Out Strength of Anchor Bolts Embedded in Concrete Members by SPH Method." Applied Sciences 11, no. 18 (September 14, 2021): 8526. http://dx.doi.org/10.3390/app11188526.
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As an important method for connecting structural members, anchor bolts have been installed in many situations. Therefore, accurate evaluation of the pull-out strength of anchor bolts has always been an important issue, considering the complicated actual installation conditions and the problem of aging deterioration of the structural members. In general, the patterns of pull-out failure of anchor bolts can be classified into three types: adhesion failure, cone failure, and bolt break. However, it sometimes shows a mixed fracture pattern, and it is not always easy to predict the accurate pull-out strength. In this study, we attempted to evaluate the pull-out strength of anchor bolts under various installation conditions using SPH, which can analyze the crack growth process in the concrete. In particular, the anchor bolt-concrete interface model was introduced to SPH analysis in order to consider the bond failure, and it was confirmed that various failure patterns and the load capacity could be predicted by proposed SPH method. After that, the influence of several parameters, such as bond stress limit, anchor bolt diameter, and the anchor bolt embedment depth on the failure patterns and the load capacity, were investigated by numerical calculation. Furthermore, several useful suggestions on the pull-out strength of anchor bolts under improper installation conditions, such as the ends of members for the purpose of seismic retrofitting, are presented.
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Minghini, Fabio, Francesco Lippi, Nerio Tullini, and Walter Salvatore. "Pullout tests on the connection to an existing foundation of a steel warehouse rebuilt after the 2012 Emilia (Italy) earthquakes." Bulletin of Earthquake Engineering 19, no. 11 (May 27, 2021): 4369–405. http://dx.doi.org/10.1007/s10518-021-01127-8.
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AbstractThe tests described in this paper were aimed at evaluating the tensile capacity of the anchorages connecting an automated pallet warehouse with an existing RC foundation. The warehouse is a new steel structure erected in the place of a previous warehouse collapsed due to the Emilia earthquake, but whose foundation remained undamaged. The investigated fastening consists of 10 post-installed, bonded threaded rods with diameter (d) and embedment depth (hef) of 20 and 500 mm, respectively. Neither anchor arrangement nor embedment depth (hef > 20d) was covered by current standards for fastening design. To reproduce the in-situ actual conditions of the fastening, an unconfined test configuration was used. The maximum loads achieved were more than 3 times greater than the seismic demand for the fastening. The tests highlighted the crucial role played by the reinforcing steel which was present in the foundation. Concrete-related failure mechanisms, such as the combined pullout and concrete cone failure mechanism typical of bonded anchors, were not activated. The observed crack patterns rather suggest the onset of a flexural failure mechanism of the concrete slab. This feature is confirmed by analytical calculations showing that, at the maximum loads achieved in the tests, the top reinforcement was likely to be yielded. In six preliminary unconfined tension tests on single anchors, steel rod failure was achieved, associated with limited cracking of the concrete surface in proximity of the anchor.
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Lanwer, Jan-Paul, Hendrik Weigel, Abtin Baghdadi, Martin Empelmann, and Harald Kloft. "Jointing Principles in AMC—Part 1: Design and Preparation of Dry Joints." Applied Sciences 12, no. 9 (April 20, 2022): 4138. http://dx.doi.org/10.3390/app12094138.
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The study described in this contribution contains a fundamental strategy to select geometries for dry joint profiles in 3D-printed concrete constructions. A database, here called the ‘joint catalogue’, contains a variety of joint types adapted from timber, steel, and bionic connections. Weighting factors and different criteria evaluate and score the various joint profiles (e.g., manufacturability, duration of manufacturing, and mechanical behaviour). Therefore, an algorithm sums up the scores leading to the preselection of better suitable profiles. The preselected joint profiles were afterwards analysed by the finite element method, determining the load capacity of the joint in a unit specimen. According to the joint catalogue, a smooth, triangular, truncated cone and arc joint profile appeared to be the optimal combination for dry joints in additive manufacturing of construction (AMC).
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Liu, Jinhao, Jinming Liu, Zhongwei Li, Xiaoyu Hou, and Guoliang Dai. "Estimating CPT Parameters at Unsampled Locations Based on Kriging Interpolation Method." Applied Sciences 11, no. 23 (November 29, 2021): 11264. http://dx.doi.org/10.3390/app112311264.
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The cone penetrometer test (CPT) has been widely used in geotechnical investigations. However, how to use the limited CPT data to reasonably predict the soil parameters of the unsampled regions remains a challenge. In the present study, we adopted the Kriging method to obtain the CPT data of an unsampled location in Adelaide, South Australia, based on the collected CPT data from six soundings around this location. Interpolation results showed that the trend of the estimated parameters is consistent with the trend of parameters of the surrounding points. From the Kriging interpolation result, we further carried out axial bearing capacity calculation of a precast concrete pile using the CPT-based direct method to verify the reliability of the method. The calculated bearing capacity of the pile is 99.6 kN which is very close to the true value of 102.8 kN. Our results demonstrated the effectiveness of the Kriging method in considering the soil spatial variability and predicting soil parameters, which is quite suitable for the application in engineering practice.
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Małek, Marcin, Marta Kadela, Michał Terpiłowski, Tomasz Szewczyk, Waldemar Łasica, and Paweł Muzolf. "Effect of Metal Lathe Waste Addition on the Mechanical and Thermal Properties of Concrete." Materials 14, no. 11 (May 23, 2021): 2760. http://dx.doi.org/10.3390/ma14112760.
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The amount of steel chips generated by lathes and CNC machines is 1200 million tons per year, and they are difficult to recycle. The effect of adding steel chips without pre-cleaning (covered with production lubricants and cooling oils) on the properties of concrete was investigated. Steel waste was added as a replacement for fine aggregate in the amounts of 5%, 10% and 15% of the cement weight, which correspond with 1.1%, 2.2% and 3.3% mass of all ingredients and 0.33%, 0.66% and 0.99% volume of concrete mix, respectively. The slump cone, air content, pH value, density, compressive strength, tensile strength, tensile splitting strength, elastic modulus, Poisson’s ratio and thermal parameters were tested. It was observed that with the addition of lathe waste, the density decreased, but mechanical properties increased. With the addition of 5%, 10% and 15% metal chips, compressive strength increased by 13.9%, 20.8% and 36.3% respectively compared to plain concrete; flexural strength by 7.1%, 12.7% and 18.2%; and tensile splitting strength by 4.2%, 33.2% and 38.4%. Moreover, it was determined that with addition of steel chips, thermal diffusivity was reduced and specific heat capacity increased. With the addition of 15% metal chips, thermal diffusivity was 25.2% lower than in the reference sample, while specific heat was 23.0% higher. No effect was observed on thermal conductivity.
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Chandra, Alfian Adie, Helen Gianditha Wayangkau, and Ahmad Gifary. "Design of Leading Type Retaining Walls: Case Study in Perumnas IV Padang Bulan, Jayapura City." International Journal of Science and Society 5, no. 1 (January 25, 2023): 53–63. http://dx.doi.org/10.54783/ijsoc.v5i1.625.
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Jayapura City is one of the Papua Province’s capital cities with an increasing population. One of the areas in Jayapura City, especially Perumnas IV Padang Bulan, is surrounded by hills. Infrastructure development in the densely packed Perumnas IV Padang Bulan area and increasingly narrow land has forced the local community to build infrastructure under the foot of the hills. Infrastructure development under the foot of the mountains is very prone to landslides or soil movement. There is a retaining wall planned so that the movement of the soil is restrained by the retaining wall so that no landslides occur, which endanger the community in the Perumnas IV Padang Bulan area. From a survey of the Perumnas IV Padang Bulan area in the form of topographic data and cone penetration data (CPT), contour data and cone penetration results (CPT) data were obtained for QC and fs values, then soil type classification was carried out with empirical correlation approaches, then active earth pressure calculations were carried out and passive from Rankine’s theory. As well as planning a safe leaning type retaining wall. From the results of the planning that has been done, the plan obtained is a leaning type retaining wall with concrete material, the height of the retaining wall reaches 3.1 meters, and the width of the foundation is 2 meters. Safe against overturning, shearing, and soil-bearing capacity.
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Gavin, Kenneth, and Barry Lehane. "Base load – displacement response of piles in sand." Canadian Geotechnical Journal 44, no. 9 (September 2007): 1053–63. http://dx.doi.org/10.1139/t07-048.
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The paper presents the results of a series of laboratory and field model pile tests performed to study the factors controlling the base pressure – settlement reponse of piles in sand. One series of tests involved the installation and load testing of steel open- and closed-ended piles in loose sand contained in a large pile testing chamber. A second series involved tests on open- and closed-ended steel piles and a concrete bored pile at a dense sand test bed site. The experiments were designed to investigate the effects of pile type, sand consistency, and installation resistance on a pile’s base response during static loading. The tests revealed that both the base capacity and stiffness of piles in sand are controlled by the degree of prestress imposed on the soil below the pile tip. Simple expressions, which require the small strain stiffness and cone penetration test data as the input parameters, are developed to predict the base pressure – settlement response. The final part of the paper employs other field tests on full-scale displacement piles and bored piles to verify the validity of the proposed approach.
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Olumuyiwa, Falowo Olusola. "Engineering Site Investigation for Foundation Design and Construction in Shale and Sandstone Derived Soils of Okitipupa Area, Southwestern Nigeria." Journal of Applied Geology 6, no. 1 (July 1, 2021): 62. http://dx.doi.org/10.22146/jag.55091.
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Geotechnical and geo-electrical investigations of Okitipupa has been carried out with the major objectives of establishing the subsoil/geology, evaluate the geotechnical properties and recommend appropriate foundation alternatives for building foundation construction. Seven borings were carried out with hand auger at two cone penetration test locations, and representative samples were collected and analyzed in the laboratory in accordance with relevant geotechnical engineering standards. In addition, six vertical electrical soundings (VES) were also conducted using Schlumberger configuration. The result of VES delineates three major geologic sequence comprising the topsoil/caprock, sand surficial aquifer, and sand intermediate aquifer. The topsoil has resistivity range of 242 – 1503 ohm-m and thickness of 3.4 - 20.9 m composed of clay sand and sand. This layer is capable of supporting shallow foundation such as simple spread, raft of reinforced concrete, with recommended allowable bearing pressure of 100 KN/m2 at depths of 1.0 m and 3.2 m in the northern and southern part of the study area respectively. The estimated settlement are less than 50 mm using foundation width of 0.6 m, but could be reduced by almost 50% if the width is greater than or equal to 2 m. The groundwater level is very deep (>10 m) and may not likely threatens the integrity of the foundation structures. The estimated allowable bearing capacity for strip footing (203 – 980 KN/m2), square footing (608 – 2940 KN/m2) within 1.4 m depth is appropriate. The capacity of driven (deep foundation) circular piles of diameters 400mm, 500mm, and 600mm, the recommended pile capacity varies at depth of 5 m (69 – 124 KN), 10 m (225 – 378 KN), and 15 m (470 – 766 KN), while that of bored circular pile ranges from (36 – 75 KN), 10 m (93 – 180 KN), and 15 m (170 – 317 KN).
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Yang, Z. X., W. B. Guo, R. J. Jardine, and F. Chow. "Design method reliability assessment from an extended database of axial load tests on piles driven in sand." Canadian Geotechnical Journal 54, no. 1 (January 2017): 59–74. http://dx.doi.org/10.1139/cgj-2015-0518.
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The accurate prediction of axial capacity remains a challenging task for piles driven in sands. Rigorous database studies have become key tools for assessing the efficacy of design methods. This paper employs the 117 high-quality entries in the recently developed Zhejiang University – Imperial College London (ZJU–ICL) database to check for potential biases between nine prediction procedures, considering a range of factors. The analysis highlights the critical importance of addressing age after driving, open and closed ends, tension versus compression, and concrete compared to steel. It also shows the hierarchy of reliability parameters associated with the alternative approaches. The “full” Imperial College pile (ICP) approach and The University of Western Australia (UWA) approaches are found to have significant advantages in eliminating potential biases. It is also argued that design load and resistance or safety factors should be varied to match the design and site investigation methods applied, as well as the loading uncertainty and degree of load cycling, which often vary between applications. Noting that predictions for base capacities Qb are inherently less reliable than for shaft Qs, especially in rapidly varying ground profiles, credible lower bound parameters (cone resistance, qc) are recommended for Qb assessment. It is also recommended that the potential effects of cycling be addressed carefully in cases that involve substantial environmental loading.
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Nguyen, Duy-Liem, Duc-Kien Thai, and Dong-Joo Kim. "Direct tension-dependent flexural behavior of ultra-high-performance fiber-reinforced concretes." Journal of Strain Analysis for Engineering Design 52, no. 2 (February 2017): 121–34. http://dx.doi.org/10.1177/0309324716689625.
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This research investigated the effects of direct tensile response on the flexural resistance of ultra-high-performance fiber-reinforced concretes by performing sectional analysis. The correlations between direct tensile and flexural response of ultra-high-performance fiber-reinforced concretes were investigated in detail for the development of a design code of ultra-high-performance fiber-reinforced concrete flexural members as follows: (1) the tensile resistance of ultra-high-performance fiber-reinforced concretes right after first-cracking in tension should be higher than one-third of the first-cracking strength to obtain the deflection-hardening if the ultra-high-performance fiber-reinforced concretes show tensile strain-softening response; (2) the equivalent bottom strain of flexural member at the modulus of rupture is always higher than the strain capacity of ultra-high-performance fiber-reinforced concretes in tension; (3) the softening part in the direct tensile response of ultra-high-performance fiber-reinforced concretes significantly affects their flexural resistance; and (4) the moment resistance of ultra-high-performance fiber-reinforced concrete girders is more significantly influenced by the post-cracking tensile strength rather than the tensile strain capacity. Moreover, the size and geometry effects should be carefully considered in predicting the moment capacity of ultra-high-performance fiber-reinforced concrete beams.
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Vischer, William. "Low-Volume Road Flexible Pavement Design with Geogrid-Reinforced Base." Transportation Research Record: Journal of the Transportation Research Board 1819, no. 1 (January 2003): 247–54. http://dx.doi.org/10.3141/1819a-36.
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Reconstruction of a U.S. Department of Agriculture Forest Service campground facility in the North Dakota National Grasslands required redesign and substantial construction change because of an unstable clay subgrade. The original proposal provided for removing the old asphalt and adding additional base and a new asphalt surface. When the asphalt cement was removed, it was found that the base course had migrated into the clay subgrade, leaving the subgrade unstable. Options explored for redesign were thickened gravel base sections, lime stabilization, and geosynthetic reinforcement. The geogrid-reinforced base was selected. Design analysis consisted of two phases: ( a) bearing capacity analysis for construction traffic and ( b) flexible pavement analysis and design to support long-term recreation traffic. The first involved primarily Tensar design methods; the second, an empirical and mechanistic approach. Empirical methods, based on 1993 AASHTO design procedures, included Tensar methods and the recent Perkins–Michigan Department of Transportation model. The mechanistic approach used the EVERSTRESS and KENLAYER elastic layered programs. All design methods used were found beneficial and are recommended. The final flexible pavement sections constructed were dictated by the construction traffic and consisted of 2 in. of asphalt concrete on a reinforced base course ranging in thickness from 4 to 12 in. The project had to be completed in 3 weeks, so investigation and testing were limited, and the design parameters were based primarily on field dynamic cone penetrometer testing and correlations. Enforcement of the limited wheel loads became a continuous inspection problem. In addition, because of the fineness of the base aggregate produced, a separation geotextile had to be added to preclude migration of the base aggregate through the geogrid into the subgrade.
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Gutlyanskii, Vladimir, Olga Nesmelova, Vladimir Ryazanov, and Artem Yefimushkin. "Dirichlet problem with measurable data for quasilinear Poisson equations." Proceedings of the Institute of Applied Mathematics and Mechanics NAS of Ukraine 35 (October 25, 2021): 12–26. http://dx.doi.org/10.37069/1683-4720-2021-35-2.
Full textAbstract:
The study of the Dirichlet problem with arbitrary measurable data for harmonic functions in the unit disk $\mathbb D$ goes to the famous dissertation of Luzin, see e.g. its reprint \cite{L}. His result was formulated in terms of angular limits (along nontangent paths) that are a traditional tool for the research of the boundary behavior in the geometric function theory. Following this way, we proved in \cite{GNR1} Theorem 7 on the solvability of the Dirichlet problem for the Poisson equations $\triangle\, U=G$ with sources in classes $G\in L^p,$ $ p>1$, in Jordan domains with arbitrary boundary data that are measurable with respect to the logarithmic capacity. There we assumed that the domains satisfy the quasihyperbolic boundary condition by Gehring--Martio, generally speaking, without the known $(A)-$condition by Ladyzhenskaya--Ural'tseva and, in particular, without the outer cone condition that were standard for boundary-value problems in the PDE theory. Note that such Jordan domains cannot be even locally rectifiable. With a view to further development of the theory of boundary value problems for semi-linear equations, the present paper is devoted to the Dirichlet problem with arbitrary measurable (over logarithmic capacity) boundary data for quasilinear Poisson equations in such Jordan domains. For this purpose, it is first constructed completely continuous operators generating nonclassical solutions of the Dirichlet boundary-value problem with arbitrary measurable data for the Poisson equations $\triangle\, U=G$ with the sources $G\in L^p,$ $ p>1$. The latter makes it possible to apply the Leray-Schauder approach to the proof of theorems on the existence of regular nonclassical solutions of the measurable Dirichlet problem for quasilinear Poisson equations of the form $\triangle\, U(z)=H(z)\cdot Q(U(z))$ for multipliers $H\in L^p$ with $ p>1$ and continuous functions $Q: \mathbb R\to\mathbb R$ with $Q(t)/t\to 0$ as $t\to \infty$. As consequences, we give applications to some concrete quasilinear equations of mathematical physics, arising under modelling various phy\-si\-cal processes such as diffusion with absorption, plasma states, stationary burning etc. These results can be also applied to semi-linear equations of mathematical physics in anisotropic and inhomogeneous media.
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Ndoj, Genciana, Armona Kastrati, Erisa Elezi, and Klodjan Xhexhi. "Capacity of Self-Sealing Concrete Embedding Crystalline Admixture." European Journal of Engineering and Technology Research 7, no. 2 (March 30, 2022): 76–80. http://dx.doi.org/10.24018/ejeng.2022.7.2.2762.
Full textAbstract:
Concrete is one of the most intelligent and widely utilized man-made materials in the construction industry. Despite this, even high-quality concrete is susceptible to porosity, which reduces its serviceability period. Furthermore, there is an increasing need to increase longevity due to environmental exposure such as soil moisture, corrosive outside elements, or structural defects forming in the surface of concrete. The use of crystalline admixtures in concrete is one of the many approaches to reducing these risks. When crystalline admixtures come into contact with water, they form thin crystals that fill pores, capillaries, and micro fractures, as a result making concrete a self-sealing material. When the concrete has dried, the crystalline particles remain dormant until they come into contact with additional water, which causes them to crystallize once more. This research aims to analyze and compare the material properties between commonly used concrete and concrete where crystalline waterproofing is present. Furthermore, experiments are conducted to evaluate each of the concrete samples: compressive strength, water permeability and flexure strength. As a result, demonstrating benefits or negative aspects in the use of crystalline admixture in the early stages of concrete is important. It is not yet defined, weather this is the future of cutting-edge concrete and the impact that it will have in the Albanian building market.
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Chen, Xu Jun, Qiao Yang, and Jun Guo. "Discussion on Formula for the Flexural Capacity of Concrete Beams Strengthened with FRP." Advanced Materials Research 1094 (March 2015): 278–81. http://dx.doi.org/10.4028/www.scientific.net/amr.1094.278.
Full textAbstract:
The flexural capacity formula of reinforced concrete structure strengthened with FRP in Code for Design of strengthening concrete structure(GB 50367—2013) was introduced, and the rationality of the formula was analyzed. The results showed that the concrete compression height is independent of the tension strength of Fiber Reinforced Plastic (FRP), and the concrete compression height decreases with the increase of the tension strain of FRP, which is contrary to fact. The flexural capacity formula of reinforced concrete structure strengthened with FRP in Code for Design of strengthening concrete structure (GB 50367—2013) is worth discussing.
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Li, Chun Xia, Zhi Sheng Ding, and Shi Lin Yan. "Analysis on Flexural Capacity of FRP Reinforced Concrete Members." Advanced Materials Research 446-449 (January 2012): 98–101. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.98.
Full textAbstract:
The balanced reinforcement ratio of FRP-reinforced concrete members and the flexural capacity under two different failure modes (concrete crushing and FRP rupture) are established, based on the analysis on flexural capacity of steel-reinforced concrete members in current concrete code. The effect of material properties on the balanced ratio, the variation of flexural capacity with different reinforcement ratio and a simplified nominal flexural capacity under FRP-rupture failure are derived.
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Yi, Wei Jian, and Yan Mei Lv. "Experimental Study on Shear Failure of High-Strength Concrete Beams with High-Strength Stirrups." Key Engineering Materials 400-402 (October 2008): 857–63. http://dx.doi.org/10.4028/www.scientific.net/kem.400-402.857.
Full textAbstract:
19 RC beams with shear span-to-depth equal to 3 were tested under a stiff testing facility, and complete load-deflection curves including the post-peak branch were obtained. Based on the test results the effects of concrete strength, stirrups strength, inclined stirrup angle, the amount of longitudinal reinforcement on failure mode, shear ductility index and shear capacity were analyzed. The test results were compared with the shear design approaches of Chinese Code and American Code. The results indicate that the shear failure of beam with appropriate web reinforcement has finite ductility. High-strength concrete beams with high-strength stirrups can increase not only the shear capacity, but also the shear ductility. The shear capacity of beams with high-strength concrete and stirrup can be designed with Chinese Code, but shear capacity of high-strength concrete beams without stirrups, or with the smaller amount of longitudinal reinforcement, and normal strength concrete beams with high-strength stirrups may be over-estimated by the Code.