scholarly journals Study on flexural performance of prestressed glulam continuous beams under control influence

2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Lidan Mei ◽  
Nan Guo ◽  
Ling Li ◽  
Hongliang Zuo ◽  
Yan Zhao

AbstractTraditional glulam beam connection mode has a weak ability to transfer bending moment, leading to insufficient joint stiffness and mostly in the form of simply supported beams. To make full use of material strength, a novel prestressed glulam continuous beam was proposed. On this basis, this paper put forward a new method to further improve the mechanical performance of the beams by controlling prestress. According to the estimated ultimate loads of the beams, six different control range values were formulated, and 12 continuous beams were tested for flexural performance. The effects of prestressing control on the failure modes, ultimate load capacity, and load versus deformation relationships of the glulam continuous beams were analyzed. The test results indicated that the flexural performance of the beams with prestressed control was significantly improved compared to the uncontrolled beams, the ultimate load was enhanced by 13.60%–45.11%, and the average steel wire stress at failure was increased from 70% of the designed tensile strength to 94%. Combined with the finite element analysis (FEA), the reasonable control range of the prestressed control continuous beams was18%–30% of the estimated ultimate load. The research in this paper can provide references for the theoretical analysis and engineering application of similar structures.

2014 ◽  
Vol 501-504 ◽  
pp. 1609-1614
Author(s):  
Zhong Peng ◽  
Jun Huang ◽  
Shao Bin Dai ◽  
Ji Xiong Liu

3 medium thick-walled cold-formed steel top-and-seat angle joints were designed. The ABAQUS nonlinear finite element analysis on earthquake resistance behaviors of the joints were conducted under low cyclic loading. The results indicate that the failure processes and failure modes of 3 specimens are basically the same, the destruction of joints derive from buckling deformation of the top-and-seat angle and buckling of the steel beam flanges; the shapes of hysteresis curves of all specimens are obvious pinch together and present spindle, the displacement ductility factors are greater than 5.5, the equivalent viscous damping factors are greater than 0.158, all the specimens possess good energy dissipation capacity. The secant stiffness variations are almost similar, each specimen represents significant degradation. Increase the thickness of angle and diameter of high-strength bolt can improve the mechanical performance of the joints. Increase the bolt diameter, the ductility, energy dissipation capacity and initial stiffness enhance obviously, however, there is no apparent effect while increasing the thickness of angle.


2012 ◽  
Vol 166-169 ◽  
pp. 1489-1497 ◽  
Author(s):  
Shi Yan ◽  
Lei Liu ◽  
Peng Li ◽  
Zhi Qiang Xin ◽  
Bao Xin Qi

The dynamic response and failure mode of light-weight steel columns under blast loads were studied in this paper by using nonlinear finite element analysis (FEA) software ANSYS/ LS-DYNA, aiming to develop the degree and modes of the excessive plastic deformation during failures of the columns under diverse parameters. The damaged columns with initial blast-induced deformation may evidently influence vertical stability of light-weight steel frame structures. During the numerical simulation, the element of three dimensional solid SOLID164 was used, and the strain rate effect on material strength was included in the material model with Plastic-Kinematic (MAT-03). The main parameters included in the analysis were boundary conditions, scaled distances of explosions, and the vertical compressive load ratios applied on tops of the columns. The results showed that the column with both two fixed ends was the most beneficial to resist blast shock wave, the horizontal displacement at the middle span of the columns were obviously decreasing as increasing of the scaled distances of the explosion, and the axial compression ratio only significantly influenced the column with a sliding end. The failure modes of the developed columns may be summarized as bending failure, direct shear failure, and bending shear combination failure.


2021 ◽  
Vol 27 (1) ◽  
pp. 45-65
Author(s):  
Falah Hassan Ibrahim ◽  
Ali Hussein Ali

Bubbled slabs can be exposed to damage or deterioration during its life. Therefore, the solution for strengthening must be provided. For the simulation of this case, the analysis of finite elements was carried out using ABAQUS 2017 software on six simply supported specimens, during which five are voided with 88 bubbles, and the other is solid. The slab specimens with symmetric boundary conditions were of dimensions 3200/570/150 mm. The solid slab and one bubbled slab are deemed references. Each of the other slabs was exposed to; (1) service charge, then unloaded (2) external prestressing and (3) loading to collapse under two line load. The external strengthening was applied using prestressed wire with four approaches, which are L1-E, L2-E, L1-E2, and L2-E2, where the lengths and eccentricities of prestressed wire are (L1=1800, L2=2400, E1=120 and E2=150 mm). The results showed that each reinforcement approach restores the initial capacity of the bubbled slab and improves it in the ultimate load capacity aspect. The minimum and maximum ultimate strength of strengthened cracked bubbled slab increased by (17.3%-64.5%) and (25.7%-76.3%) than solid and bubbled slab, respectively. It is easier to improve behavior with an increased eccentricity of the prestressed wire than to increase its length.


Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5141
Author(s):  
Edyta Bernatowska ◽  
Lucjan Ślęczka

This paper presents the results of experimental and numerical tests on angle members connected by one leg with a single row of bolts. This study was designed to determine which failure mode governs the resistance of such joints: net section rupture or block tearing rupture. Experimental tests were insufficient to completely identify the failure modes, and it was necessary to conduct numerical simulations. Finite element analysis of steel element resistance based on rupture required advanced material modelling, taking into account ductile initiation and propagation of fractures. This was realised using the Gurson–Tvergaard–Needleman porous material model, which allows for analysis of the joint across the full scope of its behaviour, from unloaded state to failure. Through experimental testing and numerical simulations, both failure mechanisms (net section and block tearing) were examined, and an approach to identify the failure mode was proposed. The obtained results provided experimental and numerical evidence to validate the strength function used in design standards. Finally, the obtained results of the load capacity were compared with the design procedures given in the Eurocode 3′s current and 2021 proposed editions.


2021 ◽  
Vol 1021 ◽  
pp. 138-149
Author(s):  
Ali Wathiq Abdulghani ◽  
Abdulkhaliq A. Jaafer

This paper presents a nonlinear finite element analysis of RC beam-column joints. A numerical study carried out through a simulation on beam-column joints failed in flexure presented by experimental study. A verification procedure was performed on two joints by finite element analysis with ANSYS APDL. The verification with the experimental work revealed a good agreement through the load-displacement relationship, ultimate load, and displacement, and crack pattern. Also, the parametric study was implemented which including strengthening the concrete members by a variable ratio of steel fibers with normal ratios (0.5%, 1%, 1.5%, and 2%) and ratios of slurry infiltrated fiber concrete SIFCON (steel fibers up to 4%, 6%, and 8%) in addition to using of partial and full strengthening with and without stirrups. The test results revealed that steel fibers enhanced the flexural strength and ductility of the tested joint. Increase the ratio of steel fibers increased the flexural capacity by (101%, 153%, 177%, and 193%) for the four normal ratios of steel fibers respectively. SIFCON concrete ratios (4%, 6%m and 8%) enhanced ultimate strength by (521%, 802%, and 906%) respectively. The use of steel fibers reinforcement instead of steel rebar enhanced the ultimate load capacity by (101%) with large displacement. Full strengthening method by use of SIFCON presented pure flexural failure with cracks spread in the joint region but use the SIFCON concrete as a partial strengthening changed the failure mode to the shear failure.


2013 ◽  
Vol 405-408 ◽  
pp. 664-667
Author(s):  
Chun Gang Wang ◽  
Yu Fei Cao ◽  
Lian Guang Jia ◽  
Hong Liu

This paper presents finite element analysis on cold-formed steel-section columns with complex edge stiffeners and web holes under axial compression. A total of 18 channel models with different parameters such as length, thickness and flange width are simulated. Failure modes, the ultimate load and the stress distribution around web holes are researched. The analysis results show that, the main failure mode of-section columns with complex edge stiffeners and web holes is distortional buckling. The carrying efficiency is higher as the thickness-width ratio increasing. Because of perforations on the web, the position of the max stress changes from the web near the mid-height of the specimens to the location adjacent to holes.


2011 ◽  
Vol 243-249 ◽  
pp. 5582-5588
Author(s):  
Ming Liu ◽  
Hua Huang ◽  
Jian Ling Hou ◽  
Bo Quan Liu

Rehabilitation of RC members with stainless steel wire mesh and permeability polymer mortar is a new method of structural strengthening with the advantages of resistance to fire, corrosion and ageing. Experiments were conducted to investigate the shear behavior of eight strengthened RC rectangular beams and one comparative RC beam. The shear mechanism of strengthened beams was analyzed, and the influences of the strengthening manners, bolts’ amount, bolts’ distance on the shear behavior of strengthened beams were discussed. The test results show that the rehabilitation greatly increase the beam’s shear load-carrying capacity, shear stiffness, and its ductility. But the range of load capacity improvement is greatly influenced by the bolts’ amount and distance, too much and dense bolts badly weaken the shear behavior of beam itself. The influences of the strengthening manners on the load capacity are puny, but the beams’ failure modes are different.


2021 ◽  
Vol 11 (5) ◽  
pp. 2348
Author(s):  
Min Sook Kim ◽  
Young Hak Lee

Many structural retrofitting methods tend to only focus on how to improve the strength and ductility of structural members. It is necessary for developing retrofitting strategy to consider not only upgrading the capacity but also achieving rapid and economical construction. In this paper, a new retrofitting details and technique is proposed to improve structural capacity and constructability for retrofitting reinforced concrete beams. The components of retrofitting are prefabricated, and the components are quickly assembled using bolts and chemical anchors on site. The details of modularized steel plates for retrofitting have been chosen based on the finite element analysis. To evaluate the structural performance of concrete beams retrofitted with the proposed details, five concrete beams with and without retrofitting were tested. The proposed retrofitting method significantly increased both the maximum load capacity and ductility of reinforced concrete beams. The test results showed that the flexural performance of the existing reinforced concrete beams increased by 3 times, the ductility by 2.5 times, and the energy dissipation capacity by 7 times.


2021 ◽  
Vol 27 (1) ◽  
pp. 45-65
Author(s):  
Falah Hassan Ibrahim ◽  
Ali Hussein Ali

Bubbled slabs can be exposed to damage or deterioration during its life. Therefore, the solution for strengthening must be provided. For the simulation of this case, the analysis of finite elements was carried out using ABAQUS 2017 software on six simply supported specimens, during which five are voided with 88 bubbles, and the other is solid. The slab specimens with symmetric boundary conditions were of dimensions 3200/570/150 mm. The solid slab and one bubbled slab are deemed references. Each of the other slabs was exposed to; (1) service charge, then unloaded (2) external prestressing and (3) loading to collapse under two line load. The external strengthening was applied using prestressed wire with four approaches, which are L1-E, L2-E, L1-E2, and L2-E2, where the lengths and eccentricities of prestressed wire are (L1=1800, L2=2400, E1=120 and E2=150 mm). The results showed that each reinforcement approach restores the initial capacity of the bubbled slab and improves it in the ultimate load capacity aspect. The minimum and maximum ultimate strength of strengthened cracked bubbled slab increased by (17.3%-64.5%) and (25.7%-76.3%) than solid and bubbled slab, respectively. It is easier to improve behavior with an increased eccentricity of the prestressed wire than to increase its length.


2020 ◽  
Vol 13 (3) ◽  
pp. 167-174
Author(s):  
Kareem Mohamed Alnebhan ◽  
Muhaned A. Shallal

In this study, three specimens of Warren truss girders composite with concrete deck slab were tested experimentally under a central monotonic load to study the effect of the existence of concrete inside the chords. The load capacity, deflection, slip between the concrete slab and steel tube, and failure modes were reported. Both chords were filled with concrete to the first specimen, only the lower chord was filled with concrete and the upper chord remained hollow to the second specimen and both chords were kept hollow in the third specimen. The result indicated that the existence of concrete inside the chords has a significant effect on the load capacity, failure pattern, and the slip. The steel tubes of the upper chord filled by concrete prevent surface plasticity failure of the upper chord under loading and increase the ultimate load by 6.68 %. Also, filling the lower chord with concrete prevents the surface plasticity failure in the supports zone and caused an increase in the ultimate load by 39.59 %. The slip at the end of the specimen of two chords filled with concrete is less by 71% than the end slip of specimen of hollow top chord and higher by 46.8 % than the specimen of two hollow chords.


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