scholarly journals Tension Strength Prediction of Transverse Branch Plate-to-Rectangular Joint with Concrete Filling

2020 ◽  
Vol 14 (54) ◽  
pp. 136-152
Author(s):  
Zhihua Xiong ◽  
Yongjian Liu ◽  
Bin Liu ◽  
Lei Jiang
Keyword(s):  
Ultimate Strength ◽  
Stress Reduction ◽  
Axial Stress ◽  
Reduction Factor ◽  
Displacement Curve ◽  
Strength Failure ◽  
Tensile Performance ◽  
Joint Connection ◽  
Concrete Filling ◽  
Tension Strength

This paper predicts the tension strength of Concrete-filled Branch Plate-to-Rectangular Hollow (CBPRH) joint by conducting experimental and theoretical analysis. A total of 46 X-joints with different geometric parameters were investigated, in which 4 specimens were tested under ultimate tension and 42 specimens were numerically analyzed. The joint’s strength, failure mode and load-displacement curve were obtained. Perfobond Leister Rib (PBR) was welded in part of the specimens to investigate its effect on joint’s tensile performance. It is shown that the ultimate strength of transverse CBPRH joint benefit from grouting of chord and installation of PBR. The ultimate strength of CBPRH joint with PBR is larger than the counterpart without PBR. Tension strength equations were proposed for both CBPRH joints with and without PBR by nonlinear regression. The chord axial stress reduction factor was discussed and a modified equation originated from hollow joint was recommended for CBPRH joint. Connection efficiency was presented and compared among branch plate-to-rectangular hollow (BPRH) joint, CBPRH joint and CBPRH joint with PBR.

scholarly journals A Review of Bolt Tightening Force Measurement and Loosening Detection

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3165 ◽  
Author(s):  
Rusong Miao ◽  
Ruili Shen ◽  
Songhan Zhang ◽  
Songling Xue
Keyword(s):  
Force Measurement ◽  
Axial Stress ◽  
High Stress ◽  
Bolted Joints ◽  
Practical Applications ◽  
Tightening Force ◽  
Existing Structures ◽  
Strength Failure ◽  
Joint Connection ◽  
Art Research

Pre-stressed bolted joints are widely used in civil structures and industries. The tightening force of a bolt is crucial to the reliability of the joint connection. Loosening or over-tightening of a bolt may lead to connectors slipping or bolt strength failure, which are both harmful to the main structure. In most practical cases it is extremely difficult, even impossible, to install the bolts to ensure there is a precise tension force during the construction phase. Furthermore, it is inevitable that the bolts will loosen due to long-term usage under high stress. The identification of bolt tension is therefore of great significance for monitoring the health of existing structures. This paper reviews state-of-the-art research on bolt tightening force measurement and loosening detection, including fundamental theories, algorithms, experimental set-ups, and practical applications. In general, methods based on the acoustoelastic principle are capable of calculating the value of bolt axial stress if both the time of incident wave and reflected wave can be clearly recognized. The relevant commercial instrument has been developed and its algorithm will be briefly introduced. Methods based on contact dynamic phenomena such as wave energy attenuation, high-order harmonics, sidebands, and impedance, are able to correlate interface stiffness and the clamping force of bolted joints with respective dynamic indicators. Therefore, they are able to detect or quantify bolt tightness. The related technologies will be reviewed in detail. Potential challenges and research trends will also be discussed.

scholarly journals Low-Cost Fiber Rope Reinforced Polymer (FRRP) Confinement of Square Columns with Different Corner Radii

Buildings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 355
Author(s):  
Qudeer Hussain ◽  
Anat Ruangrassamee ◽  
Somnuk Tangtermsirikul ◽  
Panuwat Joyklad ◽  
Anil C. Wijeyewickrema
Keyword(s):  
Ultimate Strength ◽  
Predictive Models ◽  
Axial Stress ◽  
Low Cost ◽  
Concrete Columns ◽  
Confined Concrete ◽  
Test Results ◽  
Stress Strain ◽  
Reinforced Polymer

This research investigates the behavior of square concrete columns externally wrapped by low-cost and easily available fiber rope reinforced polymer (FRRP) composites. This study mainly aims to explore the axial stress-strain relationships of FRRP-confined square columns. Another objective is to assess suitable predictive models for the ultimate strength and strain of FRRP-confined square columns. A total of 60 square concrete columns were cast, strengthened, and tested under compression. The parameters were the corner radii of square columns (0, 13, and 26 mm) and different materials of FRRP composites (polyester, hemp, and cotton FRRP composites). The strength and deformability of FRRP-confined specimens were observed to be higher than the unconfined specimens. It was observed that strength gains of FRRP-confined concrete columns and corner radii were directly proportional. The accuracy of ultimate strength and strain models developed for synthetic FRRP-confined square columns was assessed using the test results of this study, showing the need for the development of improved predictive models for FRRP-confined square columns. Newly developed unified models were found to be accurate in predicting the ultimate strength and strain of FRRP-confined columns.

scholarly journals Deriving formulations for forecasting the ultimate strength of locally dented ring-stiffened cylinders under combined axial compression and radial pressure loads

2020 ◽  
Vol 23 (3) ◽  
pp. 640-654
Author(s):  
Do Quang Thang
Keyword(s):  
Ultimate Strength ◽  
Residual Strength ◽  
Good Accuracy ◽  
Uncertainty Modeling ◽  
Radial Pressure ◽  
Mean Value ◽  
Reduction Factor ◽  
The Novel ◽  
Test Results ◽  
Parametric Studies

Introduction: This paper focuses on the derived equations to evaluate the ultimate strength of ring-stiffened cylinders with local denting damage under combined loadings. The damage generation scenarios in this research are representing the collision accidents of offshore stiffened cylinders with supply ships. Methods: Numerical analysis of structures are performed using Abaqus software after validation against the experiments from the authors. The responses from seventeen cylinder specimens are analyzed to develop the numerical methods. Results: Good accuracy results were achieved when comparing the test results and the simulation results. Parametric studies are then performed on design examples of ring-stiffened cylinders when considering both intact and damaged conditions for assessing the reduction factor. Then, the novel simple design equations to assess the residual strength of ring-stiffened cylinders after ship collision are derived based on the regression analysis. These equations have good accuracy with mean value Xm (Uncertainty modeling factor) around 1.0 and together with COV (Coefficient of Variation) lower than 5.3%. Conclusion: The accuracy and reliability of the derived equations are validated by comparing it with the existing test data in open access. It is concluded that the proposed equations have high accuracy and reliability, and convenient application for the purpose of checking the residual strength of dented offshore cylinder under ship collisions.

scholarly journals Static Strength of Friction-Type High-Strength Bolted T-Stub Connections under Shear and Compression

2020 ◽  
Vol 10 (10) ◽  
pp. 3600 ◽  
Author(s):  
Gangnian Xu ◽  
Youzhi Wang ◽  
Yefeng Du ◽  
Wenshuai Zhao ◽  
Laiyong Wang
Keyword(s):  
Friction Coefficient ◽  
Ultimate Strength ◽  
Compression Ratio ◽  
Failure Modes ◽  
Load Condition ◽  
High Strength ◽  
Shear Capacity ◽  
Displacement Curve ◽  
Clamping Force ◽  
Bolt Diameter

The friction-type high-strength bolted (FHSB) T-stub connection has been widely used in steel structures, due to their good fatigue resistance and ease of installation. While the current studies on FHSB T-stub connections mainly focus on the structural behaviors under both shear and tensile force, no research has been reported on the mechanical responses of the connections under the combined effects of shear and compression. To make up for this gap, this paper presents a novel FHSB T-stub connection, which is simple in structure, definite in load condition, and easy to construct. Static load tests were carried out on 21 specimens under different shear–compression ratios, and the finite-element (FE) models were created for each specimen. The failure modes, initial friction loads and ultimate strengths of the specimens were compared in details. Then, 144 FE models were adopted to analyze the effects of the friction coefficient, shear–compression ratio, bolt diameter and clamping force on the initial friction load and ultimate strength. The results showed that the FHSB T-stub connection under shear and compression mainly suffers from bolt shearing failure. The load–displacement curve generally covers the elastic, yield, hardening and failure stage. If the shear–compression ratio is small and the friction coefficient is large, its curve only contains the elastic and failure stage. The friction coefficient and shear–compression ratio have great impacts on the initial friction load and ultimate strength. For every 1 mm increase in bolt diameter, the initial friction load increased by about 10%, while the ultimate strength increased by about 8.5%. For each 10% increase/decrease of the design clamping force, the initial friction load decreases/increases by 7.8%, while the ultimate load remains basically the same. The proposed formula of shear capacity and self-lock angles of FHSB T-stub connection can be applied to the design of CSS-enhanced prestressed concrete continuous box girder bridges (PSC-CBGBs) and diagonal bracing.

Experimental study on the effect of flange geometry on the shear strength of reinforced concrete T-beams subjected to concentrated loads

2002 ◽  
Vol 29 (6) ◽  
pp. 911-918 ◽  
Author(s):  
Craig Giaccio ◽  
Riadh Al-Mahaidi ◽  
Geoff Taplin
Keyword(s):  
Experimental Study ◽  
Experimental Investigation ◽  
Shear Strength ◽  
Reinforced Concrete ◽  
Ultimate Strength ◽  
Failure Mechanisms ◽  
Shear Resistance ◽  
Strength Failure ◽  
Effective Depth ◽  
T Beam

This paper presents results of an experimental investigation into the effect of flange geometry on the shear strength of point-loaded, reinforced concrete T-beams. A procedure to normalise the ultimate strength and calculate a concrete contribution is implemented. This is used to discuss the effect of varying the ratio of flange width to web width and the ratio of flange depth to effective depth on the shear strength of a reinforced concrete T-beam. An increase in the ratio of flange width to web width is shown to produce an accompanying increase in the ultimate strength of a reinforced concrete T-beam, providing the ratio of flange depth to effective depth is above a certain minimum value. This increase in shear resistance with an increase in the ratio of flange width to web width continues until the flange is wide enough to allow formation of a failure mechanism whereby the load point punches through the flange.Key words: shear, T-beams, flange, reinforcing, strength, failure mechanisms.

Research Review of Seismic Failure Mode of Abutment and Influence on Deck Fall-Off

2011 ◽  
Vol 90-93 ◽  
pp. 1467-1472
Author(s):  
Xiao Li Li ◽  
Dong Liang Li ◽  
Dong Sheng Wang ◽  
Zhi Guo Sun
Keyword(s):  
Failure Modes ◽  
Seismic Analysis ◽  
Time History ◽  
Research Review ◽  
Displacement Curve ◽  
Strength Failure ◽  
Bridge Span ◽  
Bearing Stiffness ◽  
Nonlinear Time History ◽  
Beam Bridge

Well seismic performance of abutment were safety precondition of whole bridge. According to destroyed multi-span simple beam bridge of Wenchuan earthquake, failure modes of abutment were summarized. On the basis of correlation literature home and overseas, analysis methods of abutment seismic research were investigated. Nether factors should be take into account : soil-abutment interaction, abutment stiffness, bridge span number, pier’s force-displacement curve , bearing stiffness and etc.. Interspace model of seismic analysis were constituted and nonlinear time history adopted, so mechanism of abutment failure modes(strength failure, whole slide and admixture failure )was obtained. Control variables between beam and abutment were discussed. Those variables were keys of research influence on fall-off by abutment failure.

Plastic Coupling and Stress Relaxation During Nonproportional Axial-Shear Strain-Controlled Loading

2000 ◽  
Vol 123 (1) ◽  
pp. 81-87
Author(s):  
Cliff J. Lissenden ◽  
Steven M. Arnold ◽  
Atef F. Saleeb
Keyword(s):  
Stress Relaxation ◽  
Shear Strain ◽  
Stress Reduction ◽  
Large Range ◽  
Axial Stress ◽  
Axial Strain ◽  
Time Dependent ◽  
Load Path ◽  
Percent Reduction ◽  
Material Parameters

A nonproportional strain-controlled load path consisting of two segments was applied to the cobalt-based alloy Haynes 188 at 650°C. The first segment was purely axial; the axial strain was then held constant while the shear strain was increased during the second segment. The alloy exhibited about a 95-percent reduction in axial stress (298 to 15 MPa) during shear straining. This reduction was due primarily to plastic coupling, but time-dependent stress relaxation also occurred. A rate-independent plasticity model approximated the stress reduction due to plastic coupling reasonably well, but as expected was unable to account for time-dependent stress relaxation. A viscoplasticity model capable of predicting the interaction between stress relaxation and plastic coupling also predicted the plastic coupling reasonably well. The accuracy of the viscoplastic model is shown to depend greatly upon the set of nonunique material parameters, which must be characterized from a sufficiently large range of load histories.

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