Papers by Keyword: Ultimate Load

Abstract: To validate the accuracy of ANSYS V.19, an experimental model based on a previous study was used to determine the typical values of crack pattern, ultimate load, and deflection. The model was a flat slab with an internal column with dimensions of 1000 × 1000 × 100 mm³. Four groups used a slab with an edge column in parametric research. The first group studied the opening size relative to the column face. The second group of specimens studied opening sizes close to column corners. The third group consisted of four specimens: two had openings in front of the column face and two in front of the column corner to study how opening distance affected flat slab behaviour. The fourth group examined the optimum opening arrangement in slabs with two openings around the column. The findings showed that flat slab openings at the column corner had higher ultimate load capacity than those at the column face; however, increasing opening dimensions beyond the column dimension decreases punching shear capacity. If the column needs two openings, place them on opposite faces or near the corners; this minimizes ultimate load reduction.

Abstract: The paper considers the problem of the ultimate load finding for structures made of a material with different limits of tensile strength and compression. The modulus of elasticity under tension and compression is the same. It is assumed that upon reaching the ultimate strength, the material is deformed indefinitely. The calculations use a simplified material deformation diagram — Prandtl diagrams. The limiting state of a solid rectangular section under the action of a longitudinal force and a bending moment is considered. The dependences describing the boundary of the strength of a rectangular cross section are obtained. Formulas allowing the calculation of the values of the limit forces and under the action of which the cross section passes into the plastic state are derived. Examples of the analytical calculation of the maximum load for the frame and two-hinged arch are given. An algorithm is proposed and a program for calculating arbitrary flat rod systems according to the limit state using the finite element method is compiled. The proposed algorithm does not involve the use of iterative processes, which leads to an exact calculation of the maximum load within the accepted assumptions.

Abstract: This experimental study has been conducted on the efficiency of epoxy-bonded hemp fiber reinforced polymer (FRP) composites in flexural strengthening of reinforced concrete (RC) beams. A total of five RC beams were cast and tested up to failure. The test parameters included fiber thickness and strengthening configuration. The experimental results show the capability of hemp FRP composites to increase the loading capacity in flexure of RC beams compared with the un-strengthened beam. The enhancement of ultimate load becomes more significant as the fiber thickness is increased. The effectiveness of strengthened beams in U-wrapped scheme is found greater than strengthened beams in bottom-only scheme. Based on results, it indicates that hemp FRP has a potential to considerably increase the strength and stiffness of the original RC beam.

Abstract: This paper presents an experimental study on the strengthening of scaled reinforced concrete (RC) deep beam using hemp fiber reinforced polymer (HFRP) composite. HFRP is the composite material which compose of hemp fiber bonding with epoxy resin. The major benefit of using hemp fiber is that their low price, high toughness, and hemp is natural fiber product which that can be found locally. In this study 2 different fiber orientation has been apply to scaled deep beam and also different in thickness (fiber layer). Three scaled deep beam were strengthened using HFRP composite, remaining one beam was tested as control (unstrengthen) beam. The test result show that HFRP composite are effective to enhance ultimate load capacity for RC beam. The HFRP composite applied in U-Shape was result into higher ultimate load compare with the sample that applied with both side strengthen method

Abstract: This paper presents an investigation into the flexural behaviour of reinforced concrete beam with opening reinforced with two different materials i.e., steel and Glass Fiber Reinforced Polymer (GFRP). Comparison study between the two different materials were carried out and presented in this study through non-linear Finite Element Method (FEM) using the commercial ABAQUS 6.10 software package. The performance of the opening beam reinforced with GFRP is influenced by several key parameters. Simulation analyses were carried out to determine the behavior of beam with opening subjected to monotonic loading. The main parameters considered in this study are size of opening and reinforcement diameter. The results show that GFRP give 23%-29% more ductility than steel reinforcement. The result also shows when the size of opening change from 200mm to 150mm or from 150mm to 100mm the ultimate load capacity increase by 15%. In general, good agreement between the Finite Element (FE) simulation and the available experimental result has been obtained.

Abstract: For the study of fracture characteristics of ultra-high performance cementitious composites(ECC),16 different sizes of three-point bending beams were made and ultimate load, ultimate deflection and crack mouth opening displacement ,the curve andcurve of ECC were contructed,with the method of fracture work recommendedby RILEM , the external work was respectively calculated by the curve ofand, which determined the fracture energy of ECC.Results show that two kinds of calculation result are roughly equal;The influence of size effect on fracture character was: fracture energy increased with the increasing of the crack-depth ratio, the fracture energy of concrete specimen is the maximum when the crack-depth ratio is 0.4 ; is proportional to the initial crack-depth of the specimen, but there is no relationship betweenand crack-depth ratio. This paper would have great significance for the study of fracture characteristics of ECC.

Abstract: In this paper, totally 7 innovative steel concrete composite columns were investigated for axial load and reported. 6 of them were modified DSHCFT columns consisting only outer skin tube and butting concrete and the remaining one was Double Skinned Hollow Concrete Filled steel Tubular columns having outer and inner steel tube (DSHCFT), which was annularly in-filled with Self-Compacting Concrete (SCC). The concrete grade and yield strength of steel tubes used were respectively M35 and 250MPa. The ratios of outer tube diameter to its thickness were 34 to 36. The length to outer diameter (aspect ratio) and the hollowness ratio were from 2.4 to 4.5 and from 0.35 to 0.5 respectively. Mechanical behaviour in term of stiffness, confinement, ultimate strength and ductility were discussed. Load Vs mid-span deflection diagrams, failure patterns of the specimens are presented. The existence of composite action between steel and concrete and confinement of concrete were experimentally evidenced. Suitability of two existing design codes is verified. For the design of the modified DSHCFT Stub columns with SCC and DSHCFTs, a possible simplified formula is suggested.Keywords: Failure mode, Stiffness, ductility, confinement, Ultimate load, Simplified formula.

Abstract: A contrast investigation of the seismic behavior of unreinforced masonry walls with window openings strengthened with Carbon Fiber Reinforced Polymer (CFRP) sheets and sprayed Glass Fiber Reinforced Polymer (GFRP) is presented. Three wall specimens in the scale of 1/2 were tested by the horizontal cyclic loading combined with constant gravity loads. The seismic strengthening effects by two different FRP retrofitting schemes are compared in aspect of the failure modes, shear capacity, hysteresis response, deterioration of rigidity and ability of energy dissipation. The experimental results indicate that the increasing degree of shear capacity and the improvement of seismic behavior of the SGFRP-strengthened wall are significantly superior to that of the wall strengthened with epoxy-based CFRP; and the overcoat of sprayed GFRP can bond tightly and work well together with the masonry to play a critical role in earthquake resistance.

Abstract: Through strengthening experiment of four limit damage reinforced concrete beams by CFRP, the performance index of the carrying capacity, the stiffness and the ductility compared with before strengthening of reinforced concrete beams, and analyzed before and after reinforcement. It shows that the ultimate load, the stiffness and the ductility of limit damage reinforced concrete beams by CFRP have different degrees of increase and can be widely used in practical engineering.

Abstract: In order to study the mechanics properties to of concrete columns with embedded steel, analysis models of SRC columns are established by using finite element software ABAQUS. Firstly, in order to validate the rationality of the analytical model, the test specimens are modeled, the results obtained from the finite element and experimental analyses are compared to each other, it is found that the finite element behavior indicates a good agreement with the experimental behavior. Furthermore, the ductility and ultimate capacity of SRC columns are studied with the changes of steel bone ratio and the axial compressive ratio. Analytical results demonstrate that embedded steel improves the ductility of SRC columns with large axial compressive ratio and steel bone ratios have obvious effect on ductility and ultimate capacity of SRC columns. The study results have some value on the design and application of the SRC columns.