Brittle Shear Research Articles

Comparative impact behaviours of ultra high performance concrete columns reinforced with polypropylene vs steel fibres

Polypropylene (PP) fibres have primarily used to control shrinkage cracks or mitigate explosive spalling in concrete structures exposed to fire or subjected to impact/blast loads, with limited investigations on capacity improvement. This study unveils the possibility of using PP micro-fibres to improve the impact behaviour of fibre-reinforced ultra-high-performance concrete (FRUHPC) columns. Results show that the addition of fibres significantly improves the impact behaviour of FRUHPC columns by shifting the failure mechanism from brittle shear to favourable flexural failure. The addition of steel or PP fibres affected the impact responses differently. Steel fibres considerably increased the peak impact force (up to 18%) while PP micro-fibres slightly increased the peak (3%–4%). FRUHPC significantly reduced the maximum mid-height displacement by up to 30% (under 20° impact) and substantially improved the displacement recovery by up to 100% (under 20° impact). FRUHPC with steel fibres significantly improved the energy absorption while those with PP micro-fibres reduced the energy absorption, which is different from the effect of PP-macro fibre reported in the literature. The optimal fibre content for micro-PP fibres is 1% due to its minimal fibre usage and low peak and residual displacement. This study highlights the potential of FRUHPC as a promising material for impact-resistant structures by creating a more favourable flexural failure mechanism, enhancing ductility and toughness under impact loading, and advancing the understanding of the role of fibres in structural performance.

Deformation and Frictional Failure of Granular Media in 3D Analog and Numerical Experiments

Frictional sliding along grain boundaries in brittle shear zones can result in the fragmentation of individual grains, which ultimately can impact slip dynamics. During deformation at small scales, stick–slip motion can occur between grains when existing force chains break due to grain rearrangement or failure, resulting in frictional sliding of granular material. The rearrangement of the grains leads to dilation of the granular package, reducing the shear stress and subsequently leading to slip. Here, we conduct physical experiments employing HydroOrbs, an elasto-plastic material, to investigate grain comminution in granular media under simple shear conditions. Our findings demonstrate that the degree of grain comminution is dependent on both the normal force and the size of the grains. Using the experimental setup, we benchmark Discrete Element Method (DEM) numerical models, which are capable of simulating the movement, rotation, and fracturing of elasto-plastic grains subjected to simple shear. The DEM models successfully replicate both grain comminution patterns and horizontal force fluctuations observed in our physical experiments. They show that increasing normal forces correlate with higher horizontal forces and more fractured grains. The ability of our DEM models to accurately reproduce experimental results opens up new avenues for investigating various parameter spaces that may not be accessible through traditional laboratory experiments, for example, in assessing how internal friction or cohesion affect deformation in granular systems.

Analysis of failure characteristics of screen plates of ring hammer crusher used in coal handling applications

The screen plate, a critical component within a ring hammer crusher (also known as a ring granulator or rolling ring crusher), plays a vital role in the secondary crushing of coal. Functioning both as a platform for coal crushing and as a sieve to achieve the desired coal size, it is essential to understand and examine its failure characteristics to enhance its mechanical and wear resistance properties in coal handling applications. This study thoroughly explored the failure modes, mechanisms, and underlying causes of screen plate failures. Microscopic techniques such as optical microscopy (OM), scanning electron microscopy (SEM), Vickers microhardness test and spectrochemical analysis were utilised to identify the failure mechanism. Failure modes identified from the macroscopic analysis were discharged hole widening, hole wall break-off, plate edge crack, plate fracture, one-sided edge slimming, and general surface wear of the screen plate. The fractographic and wear track analysis identified the principal failure mechanisms of three-body abrasive wear, two-body sliding abrasion wear, shear-induced fatigue fracture and brittle shear fracture. The root causes of the failures are the rotor’s direct impact, defects in the parent material, the presence of hard materials in the coal and the use of unsuitable steel grade in the screen plate manufacturing. The service life of the screen plate can be improved through proper material selection, uniform crusher feeding, surface modification of the surface of the “as purchase” screen plate with appropriate wear-resistant materials, and adherence to good maintenance practices.

Engineering punching shear strength of flat slabs predicted by nature-inspired metaheuristic optimized regression system

Reinforced concrete (RC) flat slabs, a popular choice in construction due to their flexibility, are susceptible to sudden and brittle punching shear failure. Existing design methods often exhibit significant bias and variability. Accurate estimation of punching shear strength in RC flat slabs is crucial for effective concrete structure design and management. This study introduces a novel computation method, the jellyfish-least square support vector machine (JS-LSSVR) hybrid model, to predict punching shear strength. By combining machine learning (LSSVR) with jellyfish swarm (JS) intelligence, this hybrid model ensures precise and reliable predictions. The model’s development utilizes a real-world experimental data set. Comparison with seven established optimizers, including artificial bee colony (ABC), differential evolution (DE), genetic algorithm (GA), and others, as well as existing machine learning (ML)-based models and design codes, validates the superiority of the JS-LSSVR hybrid model. This innovative approach significantly enhances prediction accuracy, providing valuable support for civil engineers in estimating RC flat slab punching shear strength.

Deformation-induced, retrograde transformation of kyanite to andalusite: An example of felsic granulite in the southern Bohemian Massif

Detailed microstructural, microfabric and chemical analyses of felsic granulite within and around a ductile shear zone at the Plešovice quarry in the southern Bohemian Massif revealed deformation-induced, retrograde transformation of kyanite to andalusite. Although andalusite is absent outside the shear zone, its fraction among Al2SiO5 polymorphs significantly increases up to ∼59% inside the shear zone, while the fraction of kyanite significantly decreases from ∼98% outside the shear zone down to ∼22% inside the shear zone. Three examples of andalusite and the relict kyanite pair suggest a common topotaxial relationship such that andalusite (010) is parallel to the precursory kyanite (100), while andalusite [100] and [001] are parallel to the precursory kyanite [010] and [001], respectively, indicating that the growth of andalusite was crystallographically controlled by the precursory kyanite.The felsic granulite in the ductile shear zone at the Plešovice quarry has been repeatedly subjected to brittle shearing accompanied by pseudotachylite formation and plastic shearing with mylonitization, suggesting development of the ductile shear zone at the brittle–plastic transition zone. Mylonitization of the felsic granulite was promoted by deformation-induced K-feldspar replacement by myrmekite at temperatures of 390–440 °C assuming a pressure of 250 MPa.

Propagation and impacts on roadway of mining-induced far-field strong tremors: insights from numerical simulations

Mining-induced far-field mine tremors, which often cause strong ground tremors, are receiving more attention due to their increasing occurrence. Investigating the rock burst risk of roadway caused by those tremors is crucial to ensure production safety. In this study, Variational Mode Decomposition was used to investigate the wave characteristics of strong mine tremors. The propagation and attenuation of these tremors were explored using the dynamic analysis of Flac3d. The amplification factor was introduced to assess the impact of these tremors on roadways. Plastic zone volume increment and Brittle Shear Ratio (BSR) are used to assess the roadway failure and the rock burst potential caused by these tremors, respectively. The main findings are as follows: 1) Compared with the main frequency of near-field mine tremor waveform, the far-field mine tremors waveform are mainly low frequency below 5 Hz; 2) In the simulation, peak vibration velocities of P-wave and S-wave follow a power-law decay as the propagation distance increases, with P-wave attenuating faster than S-wave; 3) Under similar conditions, P-wave induce higher vibration velocities than S-wave, but S-wave generally exhibit a greater amplification factor than P-wave; 4) When the direction of dynamic load is consistent with the direction of maximum principal stress, the rock burst potential of roadway is higher, which explains the phenomenon that the rock burst potential of roadway under S-wave loading is higher than that under P-wave.

The axial tensile performance of DSCW-RC joints with lap-spliced bars

Joints formed between double-skin concrete shear walls (DSCWs) and reinforced concrete (RC) foundations commonly utilize lap-spliced bars to transfer forces. However, the behavior and design of these critical connections have not been thoroughly investigated. This study experimentally analyzes a steel-reinforced DSCW-to-RC foundation anchorage joint under monotonic uniaxial tension loading. Seven 1:3 scale specimens were tested to examine the effects of varying lap-spliced bar diameter, steel plate thickness, and stud bolt spacing. Crack propagation, load-displacement response, and reinforcement strain were measured. The results characterize two potential failure modes: ductile steel yielding and brittle stud shearing. Steel strains developed linearly up to yielding, demonstrating uniform transmission of tensile loads. Increased plate thickness and decreased stud spacing enhanced capacity. To mitigate sudden shear failures, the number and strength of studs must exceed the expected tensile demand. New design recommendations are proposed, including minimum stud bolt shear strength and the use of confining tie bars. This study provides an improved understanding of the behavior of DSCW-to-RC foundation lap-spliced connections, enabling resistance to axial demands while avoiding brittle failure modes. The experimental data will inform future analytical models and design provisions for these critical structural joints.

A general phase-field model for simulating impact-sliding contact failure

Multiple failure modes of cyclic impact-sliding contacts, including brittle fracture, shear failure, and low-cycle fatigue, are investigated within the work. For this regard, a general thermo-elasto-plastic phase-field model is developed and validated that considers brittle-ductile failure mode transitions and fatigue degradation effects. And a temperature-dependent cyclic constitutive relation, combined with thermal softening, damage degradation, strain hardening, and fatigue degradation, is introduced to explain the cyclic thermo-elasto-plastic behavior of bearing steels. Combining the dynamic point/line contact model and the general phase-field model, the damage evolution and failure mode transitions of typical bearing parts under impact-sliding contacts are studied. The results indicate that cage-pockets and balls undergo low-cycle fatigue at low impact-sliding velocities, while guiding surfaces of the cage and ring are subjected to shear failure during cyclic high-speed sliding. Moreover, it is revealed that the abnormal phenomenon of more severe damage for the harder material than the softer material is due to multiple effects of strong thermal softening, damage degradation, and fatigue degradation.

An Improved Anchorage System for L-Shaped FRP Composites to Enhance the Seismic Response of Beam-Column Joints in a Low-Strength Substandard Reinforced Concrete (RC) Frame

Reinforced concrete buildings are prone to collapse during seismic events due to the brittle shear failure of non-seismic beam-column joints (BCJ). In this study, two one-third scale reinforced concrete (RC) frames incorporating various non-seismic details were tested under lateral cyclic loading. One of the RC frames was used as control, while the other was strengthened using externally bonded carbon-fiber-reinforced polymer (CFRP) sheets in a L-Shaped configuration with particular attention to anchorage to evade debonding. For the strengthening process, L-shaped CFRP sheets were bonded to the inner face of columns, extended on beams both above and below the joint up to a hinge length. To avert debonding, the L-shaped CFRP sheets were fully wrapped with CFRP sheets around the column, both near the joint and at the end of the sheet. The sheets were also wrapped around the beam, through two slots in the slab that were adjacent to the beam-column interface and at the far end of the sheet. Test results confirmed that the installation of CFRP sheets in an L-shaped configuration altered the brittle-shear failure mechanism of the beam-column joints to a ductile failure by repositioning the hinges away from the columns. Additionally, the proposed anchorage method successfully eradicated the debonding and peel-off of the CFRP sheets. Moreover, strengthening with the CFRP sheets in the L-shaped configuration enhanced the strength and ductility of the RC frame by 45% and 43%, respectively. According to the findings of this study, the application of L-shaped CFRP sheets proved effective in strengthening RC frame structures.

Shear capacity of miniature beams with continuous staggered spiral stirrups

Scaled-down-reinforced concrete beams with rectangular staggered continuous spiral stirrups are experimentally investigated. Scale-down RC beams were considered in the current research due to ease of construction and economic feasibility. As the brittle shear failure should be avoided, continuous research trials have been conducted to find an effective technique to improve shear failure mechanism. Twenty-two beams were investigated for shear behavior under 4-point static push-over load considering the normal stirrups and compared with continuous staggered spiral ones. Stirrup spacing, shear arm ratio a/d, and shear reinforcement configurations are the main variables. All beams were designed and scaled down to be one-eighth of the full-scale beams. To minimize the size effect of using small-scale models, mortar was used instead of conventional concrete. The focus in this study was related to improved shear capacity, dissipated energy, and shear cracks propagation. It was found that using spiral reinforcement instead of normal one leads to a significant enhancement in shear capacity and dissipated energy by 33% and 45%, respectively. Therefore, the prototype RC model expected capacities were detailed calculated considering the scale-down factor used by authors. The experimental results were compared by calculated values according to international standard and specifications.

Age and fluid source constraints of the Haoyaoerhudong orogenic gold deposit, North China: Evidence from geochronology and noble gas isotopes

The Haoyaoerhudong gold deposit, located in the northwestern part of the North China craton (NCC), has produced over 120 metric tonnes (t) of gold since 2007. It has a total reserve of > 240 t at average gold grade of 0.62 g/t, making it one of the largest open pit gold mines in China. The steeply dipping, large-tonnage, low-grade, vein- or veinlet-type gold orebodies are hosted in strongly-deformed Mesoproterozoic carbonaceous schist of the Bayan Obo Group. The laminated/boudinaged veins/veinlets in the sinistral ductile–brittle shear zones are dominated by quartz, biotite, gold-bearing löllingite, pyrrhotite, (arseno)pyrite, with minor native gold, titanite and xenotime. In this paper, we present new in situ U–Pb geochronological data on magmatic zircon from the pre-ore dikes, on metamorphic and hydrothermal xenotime, and on hydrothermal titanite from the hydrothermally altered carbonaceous schist and auriferous quartz–sulfides veins/veinlets, as well as He-Ar isotopic analysis on gold-bearing (arseno)pyrite in the syn-ore stage. The metamorphic xenotime U–Pb age of 426 ± 6.0 Ma (2σ) records a regional metamorphic event, possibly related to the accretion of the Bainaimiao arc onto the NCC. Two pre-ore andesitic dikes yielded similar emplacement ages at ∼ 278 Ma constrained by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) U–Pb zircon data. Hydrothermal xenotime grains from the altered carbonaceous schist and auriferous quartz–sulfides veins yielded U–Pb ages of 256.0 ± 4.1 Ma (2σ) and 254.4 ± 2.1 Ma (2σ), respectively, overlapping with that of the hydrothermal titanite at 255.4 ± 0.8 Ma (2σ) from the laminated quartz–sulfides veinlets. This indicates that the gold mineralization occurred at ca. 255 Ma. The ∼ 255 Ma gold mineralization age is much younger than the previously reported Early–Middle Permian regional magmatic activity (ca. 291 Ma to 268 Ma), and may be associated with the regional sinistral strike-slip event in the late orogenic cycle related to the collision between the Siberian craton and the NCC. The 3He/4He (R/Ra) and 40Ar/36Ar values of the gold-bearing (arseno)pyrite are 0.04 to 0.09 (average = 0.07) and 375.8 to 2023 (average = 1045), which reveal the ore-forming fluids dominantly originated from the crustal rocks, with limited involvement from the mantle. Collectively, our new geochronological data, noble gas isotopic analyses, and geological evidence support a typical orogenic gold deposit model at Haoyaoerhudong.

Hydrothermally altered shear zones: A new reservoir play for the expansion of deep geothermal exploration in crystalline settings

Our study investigates the genesis of granitic reservoirs formed within a brittle shear zone in central Finland, evaluating their feasibility as deep geothermal targets. We employ a suite of laboratory-based experiments and cutting-edge analytical mineral techniques to determine the petrophysical and thermal properties of targeted granitic rocks, elucidating their formation processes. The most favorable reservoir properties were observed in granites affected by cataclasis and mineral dissolution, leading to a notable secondary porosity of ∼20 %. Reservoir quality is largely controlled by the pore network morphology. Alongside fractures, interconnected moldic, sieve, and interparticle pores contribute to substantial permeability of ∼5 × 10−14 m2 (50mD), even under high confining pressures of 50MPa (∼2km). A new geothermal play is here presented: brittle shear zones that have undergone high-temperature (∼200–300 °C) hydrothermal alteration. These findings will significantly enhance our capacity to identify and exploit prolific permeable zones in deep crystalline settings globally, thereby making a substantial contribution to our ongoing transition to cleaner energy resources.

Experimental study on dynamic shear-behavior of H-shaped SRC columns under lateral impact loading

This paper investigates the impact resistance and damage mechanism of steel reinforced concrete columns under lateral impact loading using experimental and numerical studies. First, six specimens were subjected to impact testing utilizing a horizontal lateral impact test device. Then, the effects of impact velocity, boundary condition, and impact direction on the impact response of specimens were investigated. The damage development, final damage pattern, impact force-time history, lateral displacement, and concrete strain were obtained to figure out the damage mechanism of steel reinforced concrete columns. The test results show that all specimens exhibit brittle shear damage patterns. As the impact velocity increases, the local brittle shear damage becomes more pronounced. Following experimental investigation, a finite element model was established and validated against the experimental results. The distribution of impact energy among different components and the effect of axial load on the impact resistance of specimens were obtained using finite element models. It was found that concrete dissipates the most energy among different components. However, the percentage of energy dissipated by the profiled steel increases with the increase in impact velocity, meaning that the insertion of profiled steel into concrete elements can effectively enhance the impact resistance of the structure. It was also found that the steel reinforced concrete column is more prone to local shear damage in a large range of axial load.

Cyclic behavior and numerical study of PRC coupling beam with steel truss floor slab

The coupling beam with small span-to-depth ratio is prone to brittle shear failure under the action of earthquake, so it can not play its role as the first line of defense against earthquake. Therefore, this paper proposes a method for calculating the shear bearing capacity of PRC-connected beams with reinforced truss floor plates. A more rational calculation model should be adopted based on its mechanical mechanism. In this study, ABAQUS finite element software is utilized to explore the parameters of PRC-connected beams with steel truss plates, including the span-to-height ratio, reinforcement ratio of the internal steel plate, diameter of upper and lower chord bars, and diameter of abdominal bars. The analysis shows that the span-to-height ratio, steel plate ratio and concrete compressive strength have a significant effect on the seismic behavior of PRC coupling beams with steel truss floor slab. Based on the softened tension-compression bar model combined with the multi-strip model, the theoretical calculation method of the shear capacity of PRC connected beams with steel truss bearing plates is derived. The results of comparison test and simulation verify the accuracy of the calculation results, and provide a design basis for the engineering application of PRC connected beams with steel truss floor plates.

Study on the dynamic characteristics of pile wharves subjected to underwater explosion

A test was conducted to investigate the dynamic response characteristics and damage modes of pile wharves subjected to underwater explosions. To simulate the explosion process, a fluid-solid coupling finite element model of the pile wharf was constructed. The structural damage process, response characteristics, and failure modes of the pile wharf were analyzed based on the experimental and numerical simulation results. The results showed that the main damaged components of the pile wharf were the piles, with damage modes of cracks, spalling, and brittle shear. The probability of moderate or more significant damage to the inclined piles was 25% higher than that of the vertical piles. The inclined piles with low deformation ability were more prone to local concrete brittle failure, significantly increasing the possibility of instability and failure of the pile wharf structure. The acceleration response spectrum indicated that although the structure of the pile wharf was severely damaged, the personnel on its surface slab still had a high probability of survival. The study indicates that replacing inclined piles with alternative optimized structures benefits the blast resistance of pile wharves.

Experimental Study on the Longitudinal Mechanical Behavior of Shield Tunnel in Soft-Hard Uneven Strata and the Reinforcement Effect of Longitudinal Channel Steel

This paper investigates the longitudinal behavior and failure pattern of shield tunnel, as well as the reinforcement mechanism of longitudinal channel steel, using reduced-scale tunnel models assembled with 24 lining rings. The longitudinal behavior of the shield tunnel and the reinforcement effect are discussed in terms of vertical deformation, joint deformation, and concrete cracking. The results indicate that the shield tunnel without reinforcement longitudinally deforms in a “bending and dislocation” mode, with the failure pattern dominated by bending deformation. In contrast, the failure pattern of the shield tunnel reinforced by channel steels is characterized by brittle shearing dislocation fracture of the circumferential joint. The load at which damage occurs in the reinforced tunnel model is 1.74 times and 2.04 times that of the non-reinforced staggered and straight jointed tunnels. The reinforcement reduces the horizontal convergence discrepancy of lining rings above the soft foundation spring and the adjacent lining rings, which improves the overall integrity of the tunnel structure.

Punching shear performance of star-shaped steel plates reinforced RC slab-column connections

The progressive collapse of flat plate structures due to brittle punching shear failure of reinforced concrete (RC) slab-column connections is a major concern in structural engineering. This paper proposed an innovative star-shaped steel plates (SSPs) system to achieve an effective yet practical enhancement of the punching and post-punching performance of RC slab-column connections. SSPs were fabricated from thin steel plates, welded together, and placed in the centre of the joint. Engineering cementitious composite (ECC) was also adopted to replace the joint core concrete and work with the SSPs further to improve the punching shear behaviour of the joint. To evaluate the effectiveness of the proposed system, five large-scale RC slab-column connections with different SSPs configurations and concrete materials were tested under monotonic load. The results showed that the initial stiffness of the joint was minimally affected by the presence of SSPs, but the system significantly improved the punching shear strength, post-punching load-bearing capacity, and deformation capacity of the joint. Specimens with ECC and SSPs exhibited an even higher punching shear strength and more ductile post-punching behaviour. The study also found that the optimum enhancement of the punching shear behaviour of the slab-column joint can be realised when the SSPs yield just before the joint experiences punching shear damage. Finally, formulas were developed to reasonably predict the punching shear strength and post-punching load-carrying capacity of the SSPs reinforced slab-column connections.

Postfire performance of pultruded wood-cored GFRP sandwich beams

Wood-cored sandwich components have been extensively used in constructions of buildings and bridges. However, the existing studies on the postfire behavior of these components are very limited. This study aims to quantitatively evaluate the postfire residual properties of the pultruded wood-cored GFRP sandwich (PWGS) beams. This paper mainly comprises three parts: (i) review of fire experiment of the PWGS beams; (ii) postfire bending experiments conducted on the PWGS beams with different fire scenarios and (iii) numerical study on thermal and postfire thermomechanical responses. It was found the failure modes mainly depended on the number of exposed sides and the fire damage degree. For the three-sided fire-exposed specimens (except for the one with a 25 mm-thick calcium silica board), the progressive tension rapture of the charred fibers was the dominant failure mode. The other specimens, however, exhibited the brittle in-plane shear failure of the web. Moreover, after cooling down from 250 °C to 20 °C, the GFRP and wood exhibited 68 % and 35 % of recoveries of elastic modulus respectively. A three-dimensional thermal model with kinetic thermophysical sub-models considering heat transfer, water evaporation and decomposition was developed. The developed thermal model accurately predicted the temperature responses and charring profiles. Furthermore, a thermomechanical model considering the material damage was developed to accurately predict the elastic modulus distribution, postfire residual bending capacity and failure modes. This study provides the basis for the retrofit and the reinforcement of the fire-damaged PWGS beams. In the future, study on the fire resistance of the PWGS components in fire will be required.

Effect of stirrups on shear performance of geometrically-similar reinforced concrete deep beams: An experimental study

In practical engineering, reinforced concrete (RC) beams with stirrups are the predominant form of RC beams. The geometric dimensions of RC beams are large, and the brittle shear failure of them maybe show the characteristics of size effect. However, current research primarily focuses on the size effect of shear failure in RC beams without stirrups, with less emphasis placed on those with stirrups. Furthermore, when the minimum stirrup ratio is exceeded, there is no consensus regarding on whether the size effect still exists. Therefore, the objective of the present work is to discover the influence of the stirrup ratio on the size effect in RC deep beams. In this work, the shear failure experiment of RC deep beams considering the structural size (maximum beam height of 900 mm) and stirrup ratio (0%∼0.942%) is designed and completed. The experiment results indicate that: 1) for the beams without stirrups, clearly, the corresponding size effect on the shear strength is the most obvious, with beam depth increases from 300 mm to 900 mm, the nominal shear strength decreases approximately by 41%; 2) as the stirrup ratio increases from 0 to 0.942%, the size effect is weakened with the presence of stirrups; 3) however, size effect cannot be completely eliminated even when the stirrup ratio reaches as high as 0.942%; (4) generally, for the stirrup ratio of 0.3%, there is a decrease in nominal shear strength by 20%, indicating that consideration of size effects should be taken seriously in practical concrete structure design; (5) moreover, Jin et al.’s size effect law is also compared and validated by the present test data.

Modelling of Shear-critical, Lightly Reinforced Concrete T-beams with Externally Bonded CFRP using ATENA Science

This paper presents the finite element modelling of shear-critical reinforced concrete beams strengthened with U-wrapped CFRP fabrics using ATENA. Fracture-plastic constitutive models, implemented in the context of smeared crack and crush-band approach, were employed to represent the nonlinear behaviours of concrete. CFRP U-wraps were modelled as smeared rein­forcement and bonded to the concrete surface using an interface element, considering appropriate bond properties. To this end, two large lightly reinforced concrete T-beams from tests undertaken by Brindley in 2018 were analysed and predictions of the load-deflection response and failure mode are presented to demonstrate the accuracy of the modelling. Moreover, parametric analyses were performed to assess the effectiveness of CFRP U-wraps for strengthening deteriorated members. It is shown that the response of the beams can be predicted accurately, capturing successfully the brittle shear failure mode observed experimentally. It is also shown that CFRP U-wraps are useful for reducing the brittleness of shear-critical beams.