scholarly journals Experimental and Analytical Study of Horizontally Curved I-Girders Subjected to Equal End Moments

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1132
Author(s):  
Jeonghyeon Lim ◽  
Young-Jong Kang ◽  
Jeonghwa Lee ◽  
Seungjun Kim ◽  
Keesei Lee
Keyword(s):  
Analytical Study ◽  
Experimental Studies ◽  
Bending Moment ◽  
Test Results ◽  
Ultimate State ◽  
Moment Capacity ◽  
Horizontally Curved ◽  
Stiffness Reduction ◽  
Interaction Curves ◽  
Good Agreement

If bending and torsional moments are applied to an I-shaped beam member, the coupling of those two forces could reduce the bending moment capacity of that member. Therefore, the interaction between bending and torsional moments is an important issue for horizontally curved members that are always simultaneously subjected to bending and torsion. In this study, the behavior of the horizontally curved steel I-beam was investigated through numerical analysis. The ultimate state of sharply curved members that showed large displacement was defined in accordance with the stiffness reduction ratio to consist of strength curves. Based on the analysis results, interaction curves were established, and a strength equation was derived. The uniform torsional moment capacity, curvature, and slenderness parameters were considered in the equation, which were the main factors that affected the ultimate strength of curved members. The curvature effect was considered individually, so that the strength of the straight or curved girder could be estimated with a unified equation. To verify the accuracy of the suggested equation, experimental studies were also conducted. Consequently, the suggested equation shows very good agreement with the test results, and is expected to provide useful information for the design of curved members.

scholarly journals Analysis of the Internal Mounting Forces and Strength of Newly Designed Fastener to Joints Wood and Wood-Based Panels

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7119
Author(s):  
Łukasz Krzyżaniak ◽  
Tolga Kuşkun ◽  
Ali Kasal ◽  
Jerzy Smardzewski
Keyword(s):  
Medium Density Fiberboard ◽  
Beech Wood ◽  
Experimental Studies ◽  
Bending Moment ◽  
Numerical Calculations ◽  
Medium Density ◽  
Test Results ◽  
Moment Capacity ◽  
Fagus Silvatica ◽  
3D Printed

This study aimed to numerically and experimentally analyze the effects of internal mounting forces and selected materials on the stiffness and bending moment capacity of L-type corner joints connected with novelty-designed 3D printed fasteners. The experiments were carried out using medium-density fiberboard, high-density fiberboard, beech plywood, particleboard, and beech (Fagus silvatica L.) wood. The results showed that the joints made of beech wood were characterized by the largest bending moment capacity (12.34 Nm), while the worst properties were shown by particleboard (2.18 Nm). The highest stiffness was demonstrated by plywood joints (6.56 kNm/rad), and the lowest by particleboard (0.42 kNm/rad). Experimental studies have reasonably verified the results of numerical calculations. The test results confirmed that the geometry of new fasteners promotes the mounting forces under the assembly of the joints. It was shown that the higher the density of the materials, the greater the value of the mounting forces (164 N–189 N).

Experimental Studies on Bearing Capacity of Post-Tensioned Unbonded Prestressed Concrete Hollowed Floors

2011 ◽  
Vol 368-373 ◽  
pp. 159-163 ◽  
Author(s):  
Xiao Hua Yang ◽  
Chao Yang Zhou ◽  
Xue Jun He ◽  
Zhi Qing Yang
Keyword(s):  
Bearing Capacity ◽  
Prestressed Concrete ◽  
Plastic Hinge ◽  
Experimental Studies ◽  
Load Test ◽  
Test Results ◽  
Three Stages ◽  
Hinge Model ◽  
Good Agreement ◽  
Post Tensioned

A 1/4 scales four-storey model of post-tensioned unbonded prestressed concrete hollow slab-column structure has been made to do the ultimate load test on the second-storey floor. By measuring the floor deflection, stresses of steel bars and cracks of floors, the bearing capacity of floor is explored. The bearing capacity tests of floor are divided into three stages: elastic stage, crack growth stage and destruction stage. Based on the test results and crack developments in floor, a improved plastic hinge model is carried out to predict the ultimate loads. The calculated results of the ultimate loads with improved plastic hinge model are in good agreement with the experiment data.

scholarly journals Experimental and Analytical Study on Deformation Behavior in Hogging Moment Regions of Composite Beams

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Aiming Song ◽  
Qi Luo ◽  
Shui Wan ◽  
Zhicong Li
Keyword(s):  
Analytical Study ◽  
Fatigue Behavior ◽  
Residual Deformation ◽  
Composite Beams ◽  
Fatigue Tests ◽  
Structural Deformation ◽  
Test Results ◽  
Fatigue Load ◽  
Deformation Curves ◽  
Good Agreement

The results of an experimental and analytical study on the static and fatigue behavior in steel-concrete composite beams under the hogging moment were presented in this paper, and the structural deformation was discussed cautiously and emphatically. Firstly, the static and fatigue tests on three inverted simply supported beams were conducted. The development of cracks under static loading, the load-deformation curves, and the values of residual deformation under fatigue load were recorded and analyzed in detail. Several meaningful conclusions were obtained from the analysis of experimental results. To study the development laws of residual deformation under fatigue load, the analytical methods of residual midspan deflection and residual rebar strain were proposed, respectively. The limitation and accuracy of the presented models were studied according to the comparison between the prediction and measured results. The calculation values of the proposed models showed good agreement with the test results. Finally, the design recommendations of fatigue deformation were proposed according to the experimental and analytical study on steel-concrete composite beams subjected to hogging moment.

scholarly journals Composite GFRP bars as reinforcement of concrete members under axial force and bending moment

2014 ◽  
Vol 13 (3) ◽  
pp. 167-174
Author(s):  
Piotr Szymczak ◽  
Paweł Olbryk ◽  
Maria Kamińska
Keyword(s):  
Axial Force ◽  
Experimental Studies ◽  
Bending Moment ◽  
Gfrp Bars ◽  
Concrete Members ◽  
Failure State ◽  
Glass Fibre Reinforced Polymer ◽  
Glass Fibre Reinforced ◽  
Interaction Curves ◽  
Longitudinal Strains

This paper discusses concrete members reinforced internally with composite GFRP bars (Glass Fibre Reinforced Polymer). The studies are focused on members under axial force and bending moment. Experimental studies of 4 RC columns loaded with compressive axial force, longitudinally and transversally reinforced with GFRP bars were discussed. Columns had cylinder shape with the nominal diameter of 200mm and height of 600mm. Longitudinal reinforcement contained six bars with 11mm diameter and transversal reinforcement of continuous spiral bars # 4 and #8 with spacing equal to 45mm and 60mm. Studies show that the GFRP reinforcement has very good adhesion to concrete and,in failure state reaches stresses adequate to longitudinal strains of members. This paper proves that the interaction curves can be determined on the same strain state basis as used in RC members according to EC2.

Variation of Ultimate Concrete Strain at RC Columns Subjected to Axial Loads with Bi-Directional Eccentricities

2007 ◽  
Vol 348-349 ◽  
pp. 617-620
Author(s):  
S.H. Yoo ◽  
S.W. Shin
Keyword(s):  
Bending Moment ◽  
Reinforced Concrete Beams ◽  
Minor Effect ◽  
Test Results ◽  
Axial Loads ◽  
Biaxial Bending ◽  
Moment Capacity ◽  
A Minor ◽  
Distribution Of Stress ◽  
Ultimate Concrete Strain

The distribution of stress in a nonrectangular compressed area, such as a section under a biaxial moment, is different than that of a rectangular compressed area. The properties of the compressive stress distribution of concrete have only a minor effect on the pure bending moment capacity of reinforced concrete beams, but they are important influencing factors for columns subjected to a combined axial load and a biaxial bending moment. The variation of ultimate strain of concrete according to the angle and depth of a neutral axis was investigated. Thus, the modified rectangular stress block (MRSB) model for nonrectangular compressed areas is formulated and compared to the experimental results and the existing RSB model. The MRSB method is able to provide more accurate predictions of test results for the biaxial bending moment strength than the RSB method.

Ultimate Strength of Parabolic Concrete Arches

2021 ◽  
Author(s):  
Adnan Al-kuaity ◽  
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Strength ◽  
Analytical Procedure ◽  
Bending Moment ◽  
Steel Reinforcement ◽  
Collapse Mechanism ◽  
Test Results ◽  
Concentrated Load ◽  
Lightly Reinforced Concrete ◽  
Good Agreement

This investigation is aimed to present a simple analytical approach for predicting the ultimate strength of concrete arch using theory of plasticity. Six models of two-hinged parabolic concrete arches with and without steel reinforcement were tested under concentrated load. The observed behavior of cracking strength and collapse load of the arches tested were compared with those predicted by the analytical procedure proposed here. The arches tested were un-reinforced concrete, lightly reinforced concrete, and concrete with filing iron respectively. A Good agreement is found between the proposed analysis and test results. Tests have shown that the collapse of all arches was mainly due to the formation of two plastic hinges at a point of maximum bending moment which is similar to collapse mechanism adopted in this study. The use of light concentric steel reinforcement resulted into a significant increase in the ultimate load. This increase reaches up to three times of that without reinforcement. Ductility was also found to be greatly improved due to using steel reinforcement in arches. The procedure of analysis in this paper can give a simple guide for design of concrete arch.

scholarly journals Experimental studies on the transformation from firn to ice in the wet-snow zone of temperate glaciers

1997 ◽  
Vol 24 ◽  
pp. 181-185 ◽  
Author(s):  
Katsuhisa Kawashima ◽  
Tomomi Yamada
Keyword(s):  
Experimental Studies ◽  
Ice Formation ◽  
Compression Tests ◽  
Densification Rate ◽  
Overburden Pressure ◽  
Proportionality Constant ◽  
Wet Snow ◽  
Water Saturated ◽  
The Relationship ◽  
Good Agreement

The densification of water-saturated firn, which had formed just above the firn-ice transition in the wet-snow zone of temperate glaciers, was investigated by compression tests under pressures ranging from 0.036 to 0.173 MPa, with special reference to the relationship between densification rate, time and pressure. At each test, the logarithm of the densification rate was proportional to the logarithm of the time, and its proportionality constant increased exponentially with increasing pressure. The time necessary for ice formation in the firn aquifer was calculated using the empirical formula obtained from the tests. Consequently, the necessary time decreased exponentially as the pressure increased, which shows that the transformation from firn in ice can be completed within the period when the firn aquifer exists, if the overburden pressure acting on the water-saturated firn is above 0.12–0.14 MPa. This critical value of pressure was in good agreement with the overburden pressure obtained from depth–density curves of temperate glaciers. It was concluded that the depth of firn–ice transition was self-balanced by the overburden pressure to result in the concentration between 20 and 30 m.

scholarly journals Spine Examination during COVID-19 Pandemic via Video Consultation

2021 ◽  
Author(s):  
Tom Jansen ◽  
Martin Gathen ◽  
Amadeo Touet ◽  
Hans Goost ◽  
Dieter Christian Wirtz ◽  
...  
Keyword(s):  
Pain Intensity ◽  
Range Of Motion ◽  
Test Results ◽  
Risk Of Infection ◽  
Face To Face ◽  
Reliable Tool ◽  
Provocation Tests ◽  
Active Range Of Motion ◽  
Video Consultation ◽  
Good Agreement

Abstract Introduction During the current COVID-19 pandemic video consultations are increasingly common in order to minimize the risk of infection for staff and patients. The aim of this study was to evaluate the feasibility of a spine examination via video. Methods A total of 43 patients were recruited. Each participant underwent a video-based (VB) and a conventional face-to-face (FTF) spine examination. Pain intensity, active range of motion, inspection, a neurophysiologic basic exam and provocations tests were evaluated using video-based and face-to-face methods. Results The intra-rater reliability (IRR) was measured between both examinations. Good to very good IRR values were obtained in inspection (Kappa between 0,752 und 0,944), active range of motion and basic neurophysiological examination (Kappa between 0,659 und 0,969). Only moderate matches were found in specific provocation tests (Kappa between 0,407 und 0,938). A video-based spine examination is a reliable tool for measuring pain intensity, active range of motion and a basic neurophysiologic exam. Conclusion A basic spine examination during a video consultation is possible. A good agreement of the test results between video-based and face-to-face examination could be found.

Design of combined brake system for light weight scooters

2021 ◽  
pp. 095440702110240
Author(s):  
Yuan-Ting Lin ◽  
Chyuan-Yow Tseng ◽  
Jao-Hwa Kuang ◽  
Yeong-Maw Hwang
Keyword(s):  
Ride Comfort ◽  
Brake System ◽  
Force Distribution ◽  
Test Results ◽  
Systematic Method ◽  
Braking Performance ◽  
Evaluation Indexes ◽  
Low Costs ◽  
Braking Force ◽  
Good Agreement

The combined brake system (CBS) is a mechanism that links the front and rear brakes for scooters. For two-wheeled scooters, a CBS with appropriate braking force distribution can reduce the risk of crashing accidents due to insufficient driving proficiency. The design of the braking force distribution for a CBS is challenging to the designer because it has to fulfill many requirements such as braking performance, ride comfort, reliability, and low costs. This paper proposes a systematic method to optimize the parameters of CBS. The evaluation indexes for the design are first discussed. The steps to determine the critical parameter to meet the indexes and a method to predict braking performance are developed. Finally, driving tests are carried out to verify the effectiveness of the proposed method. Experimental results showed that the deceleration of the tested scooter equipped with the designed CBS achieves an average mean fully developed deceleration (MFDD) of 5.246 m/s2, higher than the homologation requirement. Furthermore, the proposed method’s prediction of braking performance is in good agreement with the test results, with errors <1%.

Experimental study of moment carrying behavior of typical Tibetan timber beam-column joints

2021 ◽  
pp. 136943322110015
Author(s):  
Ting Guo ◽  
Na Yang ◽  
Huichun Yan ◽  
Fan Bai
Keyword(s):  
Bending Moment ◽  
Structural Performance ◽  
Test Results ◽  
Timber Beam ◽  
Rotational Stiffness ◽  
Trilinear Model ◽  
Column Joint ◽  
Loading Tests ◽  
The Moment ◽  
Relationship Of

This study aimed to investigate the moment carrying behavior of typical Tibetan timber beam-column joints under monotonic vertical static load and also evaluate the influence of length ratio of Gongmu to beam (LRGB) and dowels layout on the structural performance of the joint. Six full-scale specimens were fabricated with same construction but different Gongmu length and dowels position. The moment carrying performance of beam-column joints in terms of failure mode, moment resistance, and rotational stiffness of joints were obtained via monotonic loading tests. Test results indicated that all joints are characterized by compressive failure perpendicular to grain of Ludou. Additionally, it was found that greater LRGB leads to greater initial rotational stiffness and maximum moment of the joint by an increase of restraint length for beam end; however, offsetting dowels toward column resulted smaller stiffness and ultimate bending moment of joints, particularly, offsetting Beam-Gongmu dowels toward column changed the moment-rotation curve pattern of the beam-column joint, accompanied by a hardening stiffness at last phase. Furthermore, a simplified trilinear model was proposed to represent the moment-rotation relationship of the typical Tibetan timber beam-column joint.

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