Papers by Keyword: Deflection

Abstract: Questions arise whether construction delay combined with construction method modification of a long-span bridge will affect bridge resistance to withstand the working load in the long term. A continuous bridge with a span of 78 m - 145 m - 77 m that crosses a large river has experienced this condition. In its implementation, there was a difference in construction time compared to the initial design. As a result, it is necessary to conduct an analysis of the effects of the difference in construction time on the bridge structure. An analysis of the stages of bridge construction was carried out using the Midas Civil program to determine the stress and deflection that occurred. Stress and deflection over a long period of time were calculated to determine the effect of construction methods and delays.

Abstract: Wire ropes represent a distinct category of ropes synthesized through the intertwining or braiding of individual steel wires. This unique construction confers notable attributes such as strength, flexibility, and durability to the resultant rope. The pervasive wire ropes across diverse industries underscores their capacity to adeptly manage substantial loads and endure adverse environmental conditions finding its application in mechanical, civil, mining, and marine engineering. This paper presents usage of image processing method to detect the deflection of a steel wire rope. The system comprises of dividing the wire rope into different sections, spatial referencing, frame separation, color-based detection, morphological operations, data collection and visualization. The steel wire rope deflection program will allow designers to conveniently process the transverse deflection trajectories of a steel wire rope in real time. One may further introduce any control actions when the deflection distance reaches a threshold value. The image-based algorithm enabled a robust detection of the deformed shape as a function of time, thus obtaining its dynamic trajectories. The deflection shapes and trajectories are compared with numerical predictions made using Cosserat Rod theory, which considers the geometric nonlinearities introduced due to large deflection. The numerical solution gave a rough estimate of the static deformation state of the wire, which agrees with the experimental results. This study will be useful for Structural Health Monitoring, Safety Assurance, Fatigue Analysis and Performance optimization. Moreover, the Continuum Mechanics employs Cosserat rod theory to model continuum robots which will provide enhanced computational efficiency and better dynamic simulation capabilities[18]. The deflection shapes and trajectories are compared with analytical predictions made using Cosserat Rod theory, which considers the geometric nonlinearities introduced due to large deflection.

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: Concrete structures may become obsolete and be unfit for use to the extent that they need special attendance of repair or strengthening so as to revive them. The weakness in the buildings may be caused by natural disasters like earthquake, floods, changes of use of the buildings in which higher loads more than the design loads, e.g. vertical extension loads, are applied. When the structures are defective they need to be strengthened in order to restore their original structural integrity. Sometimes, the defect or deterioration needs to be scientifically analysed first in order to know the root cause of the problem and apply the right corrective measures. A case study on an eleven stories damaged building in is presented, starting with an investigation on causes of sudden crushing of one column and a strengthening method which embraced a number of techniques such as Land Surveying and non-destructive tests in assessing the building structural integrity. The crushed column and other columns is the ground floor were all strengthened using jacketing method and provision of additional columns at the crushed column. Keywords: Columns, crushing, non-destructive tests, concrete quality, deflection, plumb, jacketing, strengthening

Abstract: Transport industry plays a vital role in development of economy of countries. To increase the load carrying capacity of the truck, the weight of truck bed may be reduced using fibre reinforced composite material. In this work, a numerical investigation is performed to reduce the weight of the truck bed using different types of laminated composites. An extensive study is conducted using unidirectional and woven fibres of glass, carbon and Kevlar fibres with polyester, epoxy and vinyl ester resins. Carbon fibre laminated plates have higher stiffness than Glass and Kevlar composite plates. Asymmetrically hybrid composite plates have lower stiffness than symmetrically hybrid composite plates. It is observed that the stiffness of plate is increased when kevlar unidirectional fibres are arranged at top and bottom of the laminate. [K/G_w]_S hybrid composite plates has the lowest deflection than other five hybrid composite plates. An optimization study is performed to identify the influencing parameter for deflection of the composite materials among material type, fibre volumetric fraction and the thickness of plate using Taguchi method. The results revealed that thickness of the plate has more influential than other two parameters.

Abstract: Flexural resistance is the ability of a specimen to withstand force in two pedestals with vertical axis until it is broken. Flexible pavement is a type of pavement which is very dependent with pavement course underneath. The dependency of flexible pavement in both base course and subgrade makes this pavement difficult to apply in unstable soil. Using wire mesh course as reinforcement is considerably able to raise the flexural resistance. This study is aimed to analyze flexural resistance value in hot mix by using wire mesh course as reinforcement. The study is conducted by applying experimental method with designing four types of wire mesh laying models in hot mix using three points flexural test equipment. Based on the study result, it is found that hot mix with wire mesh laying 30 mm from specimen surface is the best model type with 291,85 KN flexural resistance value with 8 mm of deflection depth. In this laying, it can be concluded that wire mesh course can raise up the flexural resistance up to 35,41% compared to the hot mix without wire mesh course.

Abstract: High strength concrete (HSC) characterized by high compressive strength but lower ductility compared to normal strength concrete. This low ductility limits the benefit of using HSC in building safe structures. Nanomaterials have gained increased attention because of their improvement of mechanical properties of concrete. In this paper we present an experimental study of the flexural behavior of reinforced beams composed of high-strength concrete and nanomaterials. Eight simply supported rectangular beams were fabricated with identical geometries and reinforcements, and then tested under two third-point loads. The study investigated the concrete compressive strength (50 and 75 N/mm²) as a function of the type of nanomaterial (nanosilica, nanotitanium and nanosilica/nanotitanium hybrid) and the nanomaterial concentration (0%, 0.5% and 1.0%). The experimental results showed that nano particles can be very effective in improving compressive and tensile strength of HSC, nanotitanium is more effective than nanosilica in compressive strength. Also, binary usage of hybrid mixture (nanosilica + nanotitanium) had a remarkable improvement appearing in compressive and tensile strength than using the same percentage of single type of nanomaterials used separately. The reduction in flexural ductility due to the use of higher strength concrete can be compensated by adding nanomaterials. The percentage of concentration, concrete grade and the type of nanomaterials, could predominantly affect the flexural behavior of HSRC beams.

Abstract: This paper reports the investigation of the effect of a plate dynamic loading scheme upon bimetal joint formation at explosion welding with simultaneous stamping. The investigation results of the effect of technological parameters and matrix material upon a radial deformation and quality of explosive pressed аrmco iron+steel 3 bimetal are shown. It is determined experimentally, that additional punching in modes common for explosion welding, without their intensification, allow achieving considerable deformations and manufacturing qualitative bimetal blanks with a high factor of a part form.

Abstract: The construction of crossing ferry landings across the Arctic Shelf and the regions located in the Extreme North or Far North, as well as the Siberian and Far Eastern rivers during the winter season is a difficult task of immediate concern. Nevertheless, it is necessary to learn the ice mechanical characteristics in order to examine the bearing capacity of the ice cover at the crossing ferry landings aimed at their establishment and strengthening. The purpose of the paper is to observe the physical and mechanical features of the ice cover by means of doing simulated experiments and verifying their validity using a computational model. The research performed the studies on Young’s modulus of ice definition and bending strength. Ice beam samples were used in the simulated experiments. Their physical and mechanical properties were put to the tests carried out with a special loading device. There was a structural failure of ice beam samples influenced by pure bending. The authors performed numerical computations on the ground of the data obtained by ANSYS software. The calculations resulted in determining condition of the stress-strain state of the samples at any time of loading up to their complete breaking-up. The efficiency of the algorithm is proved by comparing numerical calculations to simulated experimental data.

Abstract: It has been established that structural analysis of ribbed panels on the carrying capacity of standard cross-sections is presented as reinforced concrete T-shaped or I-beams. However, this approach does not allow factoring in the effect of transversal ribs (diaphragms) on the accounting result for two groups of limit states. As a rule, transversal ribs are used in slabs with a greater width and serve mainly to provide its bending strength across the width mode transversely. It should be mentioned that a slab is calculated according to the beam theory based on structural mechanics models that characterize its behavior approximately in either direction along standard cross-sections. The theory of plate and shell can define the behavior under steady load of such a slab more precisely. However, applying this theory is attended with certain difficulties because of steel collaboration in multiple directions, as well as having material nonlinearity in the model. The work investigates ribbed floor panels which are modeled using modern software. The authors studied samples with prestressed and nonprestressed reinforcing as well as with or without transversal ribs. Finally, the authors find out that it is worth considering transversal ribs with regard to their reinforcement in stress calculations for standard cross-sections along a slab length. It can contribute to the development of correcting coefficients and specification of the section of the calculating theory of building constructions. The authors obtained innovative outcomes.