Failure modes and trend curves for load capacity and stiffness of OSB panels subjected to concentrated load

VicRoads, the road authority for the state of Victoria, Australia, has been undertaking extensive research into the load capacity and performance of cast-in-place reinforced concrete flat slab bridges. One of the key objectives of this research is the development of analytical tools that can be used to better determine the performance of these bridges under loadings to the elastic limit and subsequently to failure. The 59-year-old Barr Creek Bridge, a flat slab bridge of four short continuous spans over column piers, was made available to VicRoads in aid of this research. The static testing program executed on this bridge was therefore aimed at providing a comprehensive set of measurements of its response to serviceability level loadings and beyond. This test program was preceded by the performance of a dynamic test (a simplified experimental modal analysis using vehicular excitation) to establish basic structural properties of the bridge (effective flexural rigidity, EI) and the influence of the abutment supports from identification of its dynamic modal characteristics. The dynamic test results enabled a reliably tuned finite element model of the bridge in its in-service condition to be produced for use in conjunction with the static testing program. The results of the static testing program compared well with finite element modeling predictions in both the elastic range (serviceability loadings) and the nonlinear range (load levels taken to incipient collapse). Observed collapse failure modes and corresponding collapse load levels were also found to be predicted well using yield line theory.

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Performance of Reinforced Concrete Beams with Multiple Openings

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.857.162 ◽

2020 ◽

Vol 857 ◽

pp. 162-168

Author(s):

Haidar Abdul Wahid Khalaf ◽

Amer Farouk Izzet

Keyword(s):

Reinforced Concrete ◽

Ultimate Load ◽

Concrete Beams ◽

Load Capacity ◽

Reinforced Concrete Beams ◽

Design Parameters ◽

Ultimate Load Capacity ◽

Concentrated Load ◽

Simply Supported ◽

Group I

The present investigation focuses on the response of simply supported reinforced concrete rectangular-section beams with multiple openings of different sizes, numbers, and geometrical configurations. The advantages of the reinforcement concrete beams with multiple opening are mainly, practical benefit including decreasing the floor heights due to passage of the utilities through the beam rather than the passage beneath it, and constructional benefit that includes the reduction of the self-weight of structure resulting due to the reduction of the dead load that achieves economic design. To optimize beam self-weight with its ultimate resistance capacity, ten reinforced concrete beams having a length, width, and depth of 2700, 100, and 400 mm, respectively were fabricated and tested as simply supported beams under one incremental concentrated load at mid-span until failure. The design parameters were the configuration and size of openings. Three main groups categorized experimental beams comprise the same area of openings and steel reinforcement details but differ in configurations. Three different shapes of openings were considered, mainly, rectangular, parallelogram, and circular. The experimental results indicate that, the beams with circular openings more efficient than the other configurations in ultimate load capacity and beams stiffness whereas, the beams with parallelogram openings were better than the beams with rectangular openings. Commonly, it was observed that the reduction in ultimate load capacity, for beams of group I, II, and III compared to the reference solid beam ranged between (75 to 93%), (65 to 93%), and (70 to 79%) respectively.

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Flexural Behavior of Fire-Damaged Prefabricated RC Hollow Slabs Strengthened with CFRP versus TRM

Materials ◽

10.3390/ma13112556 ◽

2020 ◽

Vol 13 (11) ◽

pp. 2556

Author(s):

Zheng-Ang Sui ◽

Kun Dong ◽

Jitong Jiang ◽

Shutong Yang ◽

Kexu Hu

Keyword(s):

Failure Modes ◽

Early Stage ◽

Load Capacity ◽

Peak Load ◽

Flexural Behavior ◽

Masonry Building ◽

Fire Exposure ◽

Standard Fire ◽

Four Point Bending ◽

Strengthening Technique

In this paper, carbon fiber reinforced polymer (CFRP) and textile reinforced mortar (TRM) strengthening techniques were proposed to retrofit and strengthen fire-damaged prefabricated concrete hollow slabs. A total of six slabs, from an actual multi-story masonry building, were tested to investigate the flexural performance of reinforced concrete (RC) hollow slabs strengthened with TRM and CFRP. The investigated parameters included the strengthening method (CFRP versus TRM), the number of CFRP layers, and with or without fire exposure. One unstrengthened slab and one TRM strengthened slab served as the control specimens without fire exposure. The remaining four slabs were first exposed to ISO-834 standard fire for 1 h, and then three of them were strengthened with CFRP or TRM. Through the four-point bending tests at ambient temperature, the failure modes, load and deformation response were recorded and discussed. Both CFRP and TRM strengthening methods can significantly increase the cracking load and peak load of the fire-damaged hollow slabs, as well as the stiffness in the early stage. The prefabricated hollow slabs strengthened by CFRP have better performance in the ultimate bearing capacity, but the ductility reduced with the increase of CFRP layers. Meanwhile, the TRM strengthening technique is a suitable method for the performance improvement of fire-damaged hollow slabs, in terms of not only the load capacity, especially the cracking load, but also the flexural stiffness and deformation capacity.

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An Experimental and Numerical Study on the Flexural Performance of Over-Reinforced Concrete Beam Strengthening with Bolted-Compression Steel Plates: Part II

Applied Sciences ◽

10.3390/app10010094 ◽

2019 ◽

Vol 10 (1) ◽

pp. 94 ◽

Cited By ~ 1

Author(s):

Shatha Alasadi ◽

Zainah Ibrahim ◽

Payam Shafigh ◽

Ahad Javanmardi ◽

Karim Nouri

Keyword(s):

Failure Modes ◽

Steel Plate ◽

Numerical Study ◽

Load Capacity ◽

Plate Thickness ◽

Steel Plates ◽

Experimental Program ◽

Failure Characteristics ◽

Control Beam ◽

Concrete Failure

This study presents an experimental investigation and finite element modelling (FEM) of the behavior of over-reinforced simply-supported beams developed under compression with a bolt-compression steel plate (BCSP) system. This study aims to avoid brittle failure in the compression zone by improving the strength, strain, and energy absorption (EA) of the over-reinforced beam. The experimental program consists of a control beam (CB) and three BCSP beams. With a fixed steel plate length of 1100 mm, the thicknesses of the steel plates vary at the top section. The adopted plate thicknesses were 6 mm, 10 mm, and 15 mm, denoted as BCSP-6, BCSP-10, and BCSP-15, respectively. The bolt arrangement was used to implement the bonding behavior between the concrete and the steel plate when casting. These plates were tested under flexural-static loading (four-point bending). The load-deflection and EA of the beams were determined experimentally. It was observed that the load capacity of the BCSP beams was improved by an increase in plate thickness. The increase in load capacity ranged from 73.7% to 149% of the load capacity of the control beam. The EA was improved up to about 247.5% in comparison with the control beam. There was also an improvement in the crack patterns and failure modes. It was concluded that the developed system has a great effect on the parameters studied. Moreover, the prediction of the concrete failure characteristics by the FE models, using the ABAQUS software package, was comparable with the values determined via the experimental procedures. Hence, the FE models were proven to accurately predict the concrete failure characteristics.

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Local FRP-Reinforcement of Clay Hollow Block Panels under Shear Loading

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.817.450 ◽

2019 ◽

Vol 817 ◽

pp. 450-457

Author(s):

Antonio Borri ◽

Marco Corradi ◽

Romina Sisti ◽

Alessio Molinari ◽

Chiara Quintaliani

Keyword(s):

Failure Modes ◽

Load Capacity ◽

Shear Loading ◽

Test Results ◽

Lateral Capacity ◽

Viable Solution ◽

Splitting Failure ◽

Masonry Material ◽

Frp Reinforcement ◽

Hollow Block

The use of clay hollow blocks is common for new constructions in many parts of Europe. The results of 8 full-scale shear tests of block-masonry panels (dimensions 1.60x0.90x0.25 m) are reported in this paper. Non-defective and defective wall panels were tested in shear in the laboratory. Typical failure modes are investigated, not previously reported in the scientific literature. Test results show that the lateral load capacity of the panels is highly affected by construction defects. Furthermore, CFRPs were used in this research as local reinforcement (repair) in the area around the cracks previously opened in the masonry material. The lateral capacity for CFRP-repaired panels was restored to the original value of non-defective panels, indicating that the CFRP-repair of cracked panels is viable solution. An explanation for this phenomenon is suggested, which indicates that the high tensile strength of CFRPs can be effective in repairing cracked block-masonry. It is also argued that this large stress level of the CFRPs leads to a premature tensile CFRP crisis or a splitting failure of the blocks’ shells.

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ANALYTICAL AND EXPERIMENTAL STUDY ON REPAIR EFFECTIVENESS OF CFRP SHEETS FOR RC BEAMS

Journal of Civil Engineering and Management ◽

10.3846/13923730.2013.799095 ◽

2013 ◽

Vol 20 (1) ◽

pp. 21-31 ◽

Cited By ~ 8

Author(s):

Moatasem M. Fayyadh ◽

H. Abdul Razak

Keyword(s):

Experimental Study ◽

Failure Modes ◽

Load Capacity ◽

Fe Model ◽

Rc Beams ◽

Shell Elements ◽

Cfrp Sheets ◽

Adhesive Interface ◽

Carbon Fibre Reinforced Polymer ◽

Fibre Reinforced Polymer

This paper presents the results of both analytical and experimental study on the repair effectiveness of Carbon Fibre Reinforced Polymer (CFRP) sheets for RC beams with different levels of pre-repair damage severity. It highlights the effect of fixing CFRP sheets to damaged beams on the load capacity, mid-span deflection, the steel strain and the CFRP strain and failure modes. The analytical study was based on a Finite Element (FE) model of the beam using brick and embedded bar elements for the concrete and steel reinforcement, respectively. The CFRP sheets and adhesive interface were modelled using shell elements with orthotropic material properties and incorporating the ultimate adhesive strain obtained experimentally to define the limit for debonding. In order to validate the analytical model, the FE results were compared with the results obtained from laboratory tests conducted on a control beam and three other beams subjected to different damage loads prior to repair with CFRP sheets. The results obtained showed good agreement, and this study verified the adopted approach of modelling the adhesive interface between the RC beam and the CFRP sheets using the ultimate adhesive strains obtained experimentally.

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Behaviour of hollow concrete masonry walls with one-course bond beams subjected to concentric and eccentric concentrated loading

Canadian Journal of Civil Engineering ◽

10.1139/l02-102 ◽

2003 ◽

Vol 30 (1) ◽

pp. 181-190 ◽

Cited By ~ 1

Author(s):

Junyi Yi ◽

Nigel G Shrive

Keyword(s):

Finite Element ◽

Failure Modes ◽

Three Dimensional ◽

Masonry Walls ◽

Finite Element Models ◽

Concentrated Load ◽

Concrete Masonry ◽

Out Of Plane ◽

Concentrated Loading ◽

Concrete Masonry Walls

Three-dimensional finite element models of unreinforced hollow concrete masonry walls with one-course bond beams subjected to concentrated loading have been analyzed. The walls were modelled with different loading plate sizes, different loading locations along the wall (at the midpoint of the wall, at the end of the wall, and between these points), and different out-of-plane eccentricities (e = 0, t/6, and t/3). The hollow block units, mortar, grout, and bond beam blocks in the walls were modelled separately. Both smeared and discrete cracking methods have been utilized for predicting cracking under load. Geometric and material nonlinearities and damage due to progressive cracking were taken into account in the analyses. The predicted failure modes and ultimate capacities of the walls with the concentric concentrated load applied at the midpoint or at the end of the wall compared very well with the experimental results. When the load was between the midpoint and the end of the wall, the predicted ultimate capacity was between those for the load at the midpoint and at the end. The strength of the walls decreases with increasing out-of-plane eccentricities.Key words: finite element models, hollow masonry, smeared and discrete cracking models, concentrated load, loading locations, out-of-plane eccentricities.

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PERFORMANCE OF AXIALLY LOADED TAPERED CONCRETE-FILLED STEEL COMPOSITE SLENDER COLUMNS

Journal of Civil Engineering and Management ◽

10.3846/13923730.2013.799094 ◽

2013 ◽

Vol 19 (5) ◽

pp. 705-717 ◽

Cited By ~ 1

Author(s):

Alireza Bahrami ◽

Wan Hamidon Wan Badaruzzaman ◽

Siti Aminah Osman

Keyword(s):

Finite Element ◽

Failure Modes ◽

Load Capacity ◽

Special Kind ◽

Nonlinear Analyses ◽

Composite Columns ◽

Finite Element Software ◽

Tapered Angle ◽

Steel Composite ◽

Slender Columns

This paper focuses on the performance of a special kind of tapered composite columns, namely tapered concrete-filled steel composite (TCFSC) slender columns, under axial loading. These efficient TCFSC columns are formed by the increase of the mid-height depth and width of straight concrete-filled steel composite (CFSC) slender columns, that is, by the enhancement of the tapered angle (from 0° to 2.75°) of the tapered composite columns from their top and bottom to their mid-height. To investigate the performance of the columns, finite element software LUSAS is employed to carry out the nonlinear analyses. Comparisons of the nonlinear finite element results with the existing experimental results uncover the reasonable accuracy of the proposed modelling. Nonlinear analyses are extensively performed and developed to study effects of different variables such as various tapered angles, steel wall thicknesses, concrete compressive strengths, and steel yield stresses on the performance of the columns. It is concluded that increasing each of these variables considerably enhances the ultimate axial load capacity. Also, enhancement of the tapered angle and/or steel wall thickness significantly improves the ductility. Moreover, confinement effect of the steel wall on the performance of the columns is evaluated. Failure modes of the columns are also presented.

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Ultimate Limit Design of Strengthened Steel Columns by Mortar-Filled FRP Tubes

Mathematical Problems in Engineering ◽

10.1155/2021/6676267 ◽

2021 ◽

Vol 2021 ◽

pp. 1-9

Author(s):

Jian Hou ◽

Li Song

Keyword(s):

Failure Mode ◽

Failure Modes ◽

Load Capacity ◽

Local Buckling ◽

Ultimate Load Capacity ◽

Composite Columns ◽

Steel Columns ◽

Frp Tube ◽

Frp Tubes ◽

Ultimate Limit

The present study investigated the various failure modes of strengthened steel columns by mortar-filled fiber-reinforced polymer (FRP) tubes to analytically formulate the ultimate capacities of these steel columns. A simple and effective method, wherein a mortar-filled FRP tube was sleeved outside the steel member, was also formulated to enhance the buckling resistance capacity of compressed steel members. In addition, to facilitate the connection of the column to other structural members, the length of the sleeved mortar-filled FRP tubes is less than that of the original steel columns. Theoretical analyses were also performed on the critical sections of such composite columns at their ultimate states to identify their potential failure modes, such as FRP-tube splitting at the ends or on the insides of wrapped areas, local buckling at the steel ends of transition zones, and global buckling of the composite columns. The corresponding ultimate capacity of each failure mode was then analytically formulated to characterize the critical failure mode and ultimate load capacity of the columns. The current theoretical results were compared with those from literature to validate the applicability of the developed ultimate limit design approaches for FRP-mortar-steel composite columns.

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