Four-point Bending Load Research Articles

Flexural Behavior of Prefabricated RC Bridge Deck with Different Joint Materials

This study investigated the flexural behavior of prefabricated RC bridge decks with different joint materials, normal strength concrete or UHPC (normal strength concrete for RC deck, while UHPC means ultra-high performance concrete). A total of three specimens were tested and subjected to four-point bending loads. The load–deflection curve, strain curve, load–crack width curve, and failure mode were analyzed. Numerical models with cohesive models were built and verified with test results to explore the force-transferring mechanism. The results show that UHPC effectively improved the crack strength, flexural strength, and failure mode. Compared with the joint with normal-strength concrete, the crack strength and flexural strength increased by 66.7% and 6%, respectively. The failure mode of the specimen with UHPC as joint material changed from a concentrated cracking failure of the joint to a multi-crack development failure. The behavior of the specimen with UHPC as joint material was similar to the monolithically cast specimen. In addition, the application of the current design method was evaluated and compared with test results.

Influence of UHPFRC jacketing on the static, blast and post-blast behaviour of doubly-reinforced concrete beams

This paper investigates the effects of ultra-high performance fiber-reinforced concrete (UHPFRC) jacketing on the static and blast behavior of reinforced beams. The test program included a total of six beams with dimensions of 150 mm × 200 mm × 2440 mm, including three replicate control beams, and three replicate beams retrofitted with a 20 mm UHPFRC jacket. The beams were doubly-reinforced, with provision of compression bars and ties spaced at 75 mm throughout the beam span. Each beam type included specimens tested under quasi-static four-point bending, and repeated or singly-applied blast loads applied using a shock-tube. Under static loading the UHPFRC is shown to increase beam stiffness and capacity, however the high bond capacity of the UHPFRC, crack localization effect, and relatively low steel ratio resulted in bar rupture, thereby reducing ductility. Under repeated blast loading the UHPFRC effectively reduced maximum and residual displacements at equivalent blasts, but the crack localization which initiated at the earlier blasts eventually led to bar rupture. Under the singly-applied blast, the UHPFRC was found to reduce displacements, and better control damage when compared to the companion RC beam, without bar rupture. As part of the numerical study, finite element (FE) modelling was used to predict the blast response and damage in the test beams. A parametric study is also used to examine the effects of steel ratio, jacket thickness and jacket interface location on blast behavior.

Experimental and numerical investigation of 3D-Printed bone plates under four-point bending load utilizing machine learning techniques

The fused deposition modeling (FDM) technique is widely used to produce components for various applications and has the potential to revolutionize orthopedic research through the production of custom-fit and readily available biomedical implants. The properties of FDM-produced implants are significantly influenced by processing parameters, with layer thickness being a crucial parameter. This study investigated the effect of layer thickness on the flexural properties of Polylactic Acid (PLA) bone plate implants produced by the FDM technique. Experimental results showed that the flexural strength is inversely proportional to the layer thickness due to the variation of voids in the specimens. A 3D finite element (FE) model was developed using Abaqus/Explicit software by incorporating the Gurson-Tvergaard (GT) porous plasticity model to predict the elastoplastic and damage behavior of specimens with different layer thicknesses. The characterization of the elastoplastic and GT parameters was done using a tensile test and by the calibration of a machine learning algorithm. It was shown that the FE model was able to predict the flexural behavior of 3D-printed solid plates with a maximum error of 6.13% in the maximum load. The optimal layer height was found to be 0.1 mm, providing both high flexural strength and adequate bending stiffness.

Non-linear 3D finite element analysis of built-up cold-formed steel section beam subjected to four-point bending load

The behaviour of cold-formed steel (CFS) built-up section beams under the flexural load has become an attentive area for search, especially with associated complex failure modes, such as local, distortional, lateral-torsional, and global buckling. Previous studies in this area have primarily focused on the compression capacity of CFS members, neglecting their flexural behaviour. Moreover, the CFS beam flexural analysis is more complex in terms of failure mode form and design. This study conducted A 3D non-linear finite element analysis (FEA) run on ABAQUS software on a CFS built-up section beam that was tested under four-point bending. This study examines the bending response of the built-up beam in terms of its load-bearing capacity, the ways in which it fails, and the stress distribution among its cold-formed steel components. The constitutive material laws for CFS, the screws modelling strategy and the contact interaction between the CFS components were considered in this study. The finite element model was verified by comparing it to the experimental results from a previously published study, focusing on the load–deflection response and how the beam failed. The results demonstrated that the FEA could replicate the flexural response of the CFS built-up section beam with an acceptable level of accuracy. Furthermore, the stress profile evaluation showed that the compression flange was the most affected component during the four-point bending loading. Overall, the FEA model developed in this study is a valid tool for predicting the bending behaviour of a CFS built-up section beam and assessing design variables for this type of beam under flexural loading.

Assessment of Flexural Performance of Reinforced Concrete Beams Strengthened with Internal and External AR-Glass Textile Systems

This paper is an experimental study of the effectiveness of using internal and external alkali-resistant glass fabric textile (AR-GT) layers for flexural strengthening of reinforced concrete (RC) beams. The experimental work compares internal single and triple layers of AR-GT as supplemental flexural reinforcement with textile-reinforced mortar (TRM) in RC beams subjected to four-point bending loading. In addition, a control beam specimen is cast with no AR-GT fabric. Monitoring the load–deflection curves, crack patterns, and strengthening layer performance showed that using AR-GT for internal and external layers increased the load-carrying capacity of RC beams. The failure patterns of beams with one external AR-GT layer and three internal AR-GT layers showed a similar trend, with higher loading capacity and lower deflections than the other beams. Three internal textile AR-GT layers recorded higher flexural strength (52%) than one internal layer (6.3%), compared to the control beam specimen. Moreover, using one layer of external AR-GT fabric exhibited higher flexural strength than using one or three internal layers (56.8%).

An innovative method for improving the cyclic performance of concrete beams retrofitted with prefabricated basalt-textile-reinforced ultra-high performance concrete

Retrofitting reinforced concrete structures (RC) with textile reinforced concrete is an alternative material. In this paper, the primary objective is to develop a novel type of strengthening method for RC structures by utilizing prefabricated textile-reinforced concrete composites. This study examined the flexural behavior of RC beams retrofitted with prefabricated basalt textile reinforced concrete (BTRC) panels. An experimental study was conducted on five retrofitted reinforced concrete beams to demonstrate the effectiveness of this strengthening method. A cyclic four-point bending load test was performed to determine the flexural behavior of BTRC retrofitted reinforced concrete beams. Polymer concrete is used to join the BTRC composite panel, which is constructed from layers of ultra-high performance fiber reinforced concrete (UHPFRC) and basalt textile. A comparison is made between the results obtained using cast-in-situ strengthening and those obtained using textile layers. Based on the results, prefabricated BTRC strengthening method was more effective than cast-in-place strengthening in improving the loading carrying capacity of reinforced RC beams. Compared to cast-in-situ retrofitting, the flexural strength was improved by 56%. In addition, the proposed method for connecting prefabricated BTRC composites to RC beams resulted in the tensile rupture of BTRC layers. As a result, BTRC composites can improve the flexural performance of reinforced concrete beams due to their maximum capacity. This method is an effective and affordable method, and the retrofitting technique was successful. The advantages of this method may outweigh the disadvantages of other methods.

On the Fatigue Strength of Welded High-Strength Steel Joints in the As-Welded, Post-Weld-Treated and Repaired Conditions in a Typical Ship Structural Detail

Weld quality and life extension methods of welded details in ship structures made of high-strength and ultra-high-strength steels are of high importance to overcome the issues related to the fatigue characteristics of welded high-strength steels. The current work experimentally and numerically investigated the fatigue strength of a longitudinal stiffener detail, typically present in the bulkhead connections of ship hull. Two high-strength steel grades, namely EQ47TM and EQ70QT steels, were studied in welded plate connections using gas metal arc welding with rutile-cored wires. Fatigue tests were carried out on both small-scale specimens under axial and large-scale beam specimens under four-point bending loading. In addition to the joints tested in the as-welded condition, the high-frequency mechanical impact (HFMI) treatment was considered as a post-weld treatment technique in the fatigue test series. Furthermore, the large-scale beam specimens were pre-fatigued until substantial fatigue cracks were observed, after which they were re-tested after weld repairing and post-weld treatments to investigate the potential to rehabilitate fatigue-cracked ship details. The joints in the as-welded condition were performed in accordance with the current design recommendations. Due to the severe transition from the base material to the weld reinforcement in the joints welded with the rutile-cored wire, a successful HFMI treatment required geometrical modification of weld toe using a rotary burr to avoid any detrimental sub-cracks at the HFMI-treated region. Alternatively, the use of solid filler wires could potentially overcome these issues related to the welding quality. Repaired and post-weld-treated welds performed well in the re-tests, and the fatigue strength was almost twice higher than that of tests in the as-welded condition.

Four-point bending behaviors of CFRP trapezoidal corrugated sandwich plates

The stiffness, failure load and failure mechanism of carbon fibre reinforced plastic (CFRP) composite trapezoidal corrugated sandwich plates (CTCSPs) subjected to four-point bending load were studied by experiment, modelling prediction and parametric analysis. With orthogonal anisotropic lay-ups containing ± θ plies (θ = 15°, 45° and 90°), three all-CFRP specimens were fabricated by mold hot pressing and secondary bonding. The four-point bending behaviors of specimens were tested and compared, and the analytical expressions of stiffness and failure load were provided. Four buckling failure modes and four strength failure modes were analytically considered. The spatial location and time sequence of eight failure modes were revealed by numerical linear buckling and progressive damage models established in ABAQUS. The modelling stiffness, failure load and failure process agreed with the four-bending experimental results. By increasing θ, the limit load of the specimens first increases and then decreases while the stiffness decrease. Correspondingly, the initial failure modes are shear corrugation fracture, debonding and face fracture. The variations in stiffness parameters and failure mechanism maps were presented; the latter can simultaneously predict the limit load and failure mode. The limit load and stiffness of CTCSPs can be improved more obviously by increasing the number of the face plies than by expanding the core plies.

Experimental study on cyclic flexural behaviour of GFRP-reinforced seawater sea-sand concrete slabs with synthetic fibres

Seawater and sea-sand (SWSS) concrete is a new type of concrete with many economic and environmental benefits. However, chloride-induced corrosion of steel reinforcement is a major problem associated with this type of concrete. Due to its excellent resistance in chloride environments glass fibre reinforced polymer (GFRP) reinforcement could be utilized in SWSS concrete as an alternative to steel Adding fibres can also improve the concrete properties reinforced with GFRP bars. Fibres can affect the post-crack response and failure mode of GFRP reinforced concrete and also improve the bond between rebar and concrete. This study focused on the flexural behaviour of GFRP reinforced SWSS concrete slabs with or without fibre incorporation which has not yet been fully addressed in the literature. Polypropylene (PP) and polyvinyl alcohol (PVA) fibres were used for the concrete reinforcement. Under-reinforced (ρ < ρb) and over-reinforced (ρ > ρb) GFRP reinforced concrete (RC) slabs were prepared and subjected to four-point cyclic bending loads. The results show that GFRP bar is a promising alternative to steel for SWSS concrete reinforcement. The GFRP RC slabs with plain SWSS concrete had a cracking moment which was 13% lower than the values predicted by the ACI 440.1R-15 provisions. However, adding fibres, particularly PP fibres, could successfully compensate for this reduction. Variation in GFRP reinforcement ratio had almost no effect on cracking moment. With the addition of fibres, the cracking moment and ultimate strength of the slabs were both improved. Crack width and crack spacing were reduced in fibre-reinforced SWSS concrete slabs compared with the plain concrete counterparts. Fibres reduced the residual deflection of the slabs at the end of each cycle. Comparing experimental deflection results with the values predicted by different models revealed that there is no available model could satisfactorily predict deflection for all the GFRP reinforced SWSS slabs.

Experimental tests of FRP-HSC hybrid beams under four-point bending

This paper provides an experimental study of a new fiber-reinforced polymer (FRP)-high strength concrete (HSC) hybrid beam, which consists of a glass FRP (GFRP) I-shaped profile beam strengthened with a layer of HSC on top and carbon FRP (CFRP) sheets on the web. In this study, a total of two GFRP I-shaped profile beams, two GFRP I-shaped profile beams strengthened with CFRP sheets on the web and nine FRP-HSC hybrid beams were tested under four-point bending loading. The test parameters varied for the existence of CFRP sheets, the flange width of the GFRP profile, the width of the HSC slab, the type of shear connectors and the interfacial connection method. The test results indicated that bonding CFRP sheets, increasing the flange width and HSC slab width all showed positive effect on the ultimate bearing capacity and initial rigidity. Compared with U-shaped GFRP shear keys and inverted T-shaped GFRP shear keys, the hybrid beams using steel bolts had the highest ultimate load capacity and initial rigidity. The hybrid beams using the composite-bond interface (CB) performed better than the hybrid beams using wet-bond (WB) and dry-bond (DB) interfaces.

Finite element modeling of debonding failure in CFRP-strengthened steel beam using a ductile adhesive

Carbon fiber-reinforced polymer (CFRP) composites externally bonded to the tensile flange of the steel beam are an effective strengthening technique. Due to the apparent effect of the adhesive toughness on the debonding behavior between the CFRP and steel, this paper focuses on the CFRP-strengthened steel beam using a ductile adhesive and the adhesive selection in the strengthening work. Three-dimensional (3-D) finite element (FE) models were proposed to simulate the mechanical response of the CFRP-strengthened steel beam under a static four-point bending load. The failure of a ductile adhesive was modeled using the trapezoidal mixed-mode cohesive zone model (CZM) coded in the user subroutine (UMAT) of ABAQUS. The effectiveness of the trapezoidal CZM was validated by the experiment in the literature, and the debonding characteristics using different laminate thicknesses and lengths were clarified by the stress and damage analysis. In terms of plate-end debonding failure mode, the ductile adhesive is more appropriate for the CFRP-strengthened steel beam due to its reduced normal stress, increased mixed-mode fracture energy, and more uniform stress distribution.

Experimental Investigation of the Effect of Steel Fibers on the Flexural Behavior of Corroded Prestressed Reinforced Concrete Beams

Rebar corrosion and its consequences are one of the most common damages to reinforced concrete (RC) structures. In structures with greater sensitivity, such as prestressed reinforced concrete (PRC) structures, where steel elements, including prestressed tendons, play a more significant role in supporting the structure, the importance of this issue increases. Methods for repairing and reinforcing such structures have been developed, including incorporating fibers into the concrete mixture to improve its mechanical properties, particularly its bending resistance. This paper presents the results of an experiment that studied the influence of steel fibers on the flexural behavior of PRC beams subjected to accelerated corrosion. Twelve beams with a rectangular cross-section of 150 mm × 300 mm and a length of 2000 mm were fabricated. The steel fibers used in the experiment were corrugated and hooked-end types, with volume fractions of 0.5% and 1.0% in the concrete. Nine beams were subjected to accelerated corrosion testing, with three of them being without fibers and the remaining six being reinforced with steel fibers at volume fractions of 0.5% and 1.0%. Each group of three beams was exposed to three different levels of corrosion, namely 5%, 10%, and 15%. The specimens were tested after exposure to corrosion through a four-point bending load. The accelerated corrosion was induced using an electric current on the prestressing tendons. The results indicated that different levels of corrosion reduced the final bearing capacity and other behavioral characteristics of the specimen, including the amount of energy absorption, effective hardness, and midspan displacement. Adding fibers to the concrete mixture positively affects the compensation of these reduced capacities. Moreover, the amount of this compensation was directly correlated with the volume fraction of used fibers.

Design of hierarchical lattice structures attainable by additive manufacturing techniques

Readiness of new materials that are simultaneously lightweight, damage-resistant, multifunctional, and sustainable is a primary need for many technology sectors. Thanks to additive manufacturing, lattice materials appear to be ideal candidates to meet this challenge. By designing their unit cells and structural organization, multiscale materials with unique combinations of properties can be obtained. Nevertheless, many gaps remain to be filled for their effective and efficient design. Nature, exploiting hierarchical architectures on a material scale, actually amplifies the properties of biological materials and combines them in ways we cannot achieve yet in synthetic materials. In materials design, we are still far from such a level of perfection. To narrow this gap and expand the current knowledge on the effects of hierarchy on the mechanical behaviour of materials, we numerically studied the mechanical response of 3D hierarchical lattice specimens under a four-point bending loading scenario. For this, we selected two types of unit cells with different structural behaviour and combined them together into different specimen topologies. The results show that, through hierarchy, it is possible to tailor lattice material performances, achieving benefits in terms of both specific mechanical properties and multifunctionality. The evidence found opens new horizons for applications such as heat exchangers, mechanical filters, scaffolds, energy storage, and packaging.

The effect of surface treatments on the adhesive bond in all-ceramic dental crowns using four-point bending and dynamic loading tests

The aim of this study was to determine the effect of sandblasting, grinding and plasma treatment on the adhesive bond strength between framework ceramic (Y-TZP) and veneering ceramic (feldspar ceramic). Therefore, four-point bending specimens (n = 180) were cut from densely sintered 3Y-TZP blanks. Subsequently, 80 of these samples received surface treatment by sandblasting and 80 samples by grinding. A reference group (20 samples) was not processed. Half of the specimens that received a surface treatment were additionally exposed to an oxygen plasma treatment. After processing, all specimens were manually veneered with feldspar ceramic and examined with a four-point bending test to evaluate the strain energy release rate G. The surface treatment parameters that achieved the highest and lowest G were transferred to real geometries of a posterior crown (n = 45). The crowns’ ceramic framework was sandblasted and veneered by hand. The all-ceramic crowns were tested in a dynamic loading test and Wöhler curves were evaluated. Four-point bending samples blasted at an angle of 90° at 6 bar and a working distance of 1.5 cm without plasma treatment achieved the highest energy release rate. Samples blasted at an angle of 90° at 2 bar and a working distance of 1 cm with plasma treatment achieved the lowest energy release rate. Overall, plasma treatment did not improve bond strength. In the dynamic loading test, the group blasted with 2 bar showed the best results.

Hierarchical bioinspired architected materials and structures

Designing new materials that are both lightweight, damage-tolerant, and sustainable is a primary requirement for the advancement of many technological fields. To date, lattice materials appear to be ideal candidates for achieving such multifunctionality at the material scale and leveraging the structural hierarchy can pave the way to amplify their performance. Nature teaches us that, by designing multiscale architectures through a “bottom-up” logic, it is possible to improve and fine-tune the properties of biological building blocks to get robust and multifunctional materials. Yet, we are still far from achieving such a level of perfection that Nature has. In an attempt to narrow this gap and understand the role of hierarchical strategies in lattice structures, we studied, by finite element modeling, 3D hierarchical lattice structures formed by “beam-based” elementary units. Specifically, we selected two types of unit cells with different mechanical behaviors, we combined them into different topological configurations – through hierarchy and engineering approach – and we studied their mechanical behavior under four-point bending loading. The results of this study are twofold: introducing structural heterogeneity by mixing different unit cell types can be beneficial in terms of mechanical properties, while introducing structural hierarchy does not lead to significant improvements in the deformation behavior of the lattice structures analyzed. The latter, however, significantly changes the surface-to-volume ratios of the lattice structures and thus extends their functionality. The evidence found may open new horizons for applications such as heat exchangers, mechanical filters, tissue regeneration scaffolds, energy storage systems, and packaging.

Impedance-based damage assessment of steel-ECC composite deck using piezoelectric transducers

The excellent crack and fatigue resistance of Engineering Cementitious Composites (ECC) materials makes it promising to be used in orthotropic bridge deck system. However, overloading and fatigue load might cause structural damage and, consequently, structural performance degradation. In this work, the piezoelectric lead-zirconate-titanate (PZT) transducers are used to identify the structural damage of the steel-ECC composite deck by implementing both experimental test and numerical simulation. Two steel-ECC composite deck are prepared and four-point bending loading tests are performed on the two specimens to introduce several damage scenarios by gradually increasing the load. The impedance output signals of the piezoelectric sensors are measured under different damage scenarios, and the damage index are extracted to identify the structural damage. A finite element model of the steel-ECC composite deck is established, and the impedance signals with different damage scenarios are calculated and used to assess the structural damages. According to the experimental test and numerical simulation, the impedance-based technology performs to be an effective way to identify the structural damage of the steel-ECC composite deck.

Damage evolution detection in a pipeline segment under bending by means of acoustic emission

A steel pipeline segment of 2.5 m length was subjected to quasi-static four-point bending load in three steps for studying the initial cracking and damage accumulation based on the Acoustic Emission (AE) technique and by the direct current potential drop (DCPD) technique. For the latter, a new post-test analysis method was established. AE is found more sensitive to crack initiation than DCPD. Formation of mesoscopic and macroscopic cracks as well as their closure and the resulting friction generate weighted peak frequencies below 400 kHz, whereas microscopic cracking produces AE with broad band spectra identifiable by weighted peak frequencies above 400 kHz. Critical states alike the maximum load level and the leak opening were accompanied by peak amplitudes above 85 dBAE. This rather fundamental study provides a data base for possibly developing advanced strategies of detection and alarm systems based on acoustic monitoring of pipelines, or at least, steel structures.

Experimental study on shear performance of basalt fiber concrete beams without web reinforcement

In this study, we report the results of an experimental investigation conducted under a four-point bending loading in order to evaluate the shear performance of concrete beams reinforced with basalt fiber without web reinforcement. According to the experimental results, it is evident that the final failure morphology of concrete-basalt fiber concrete composite beams and conventional concrete beams was shear failure, whereas the failure morphology of concrete beams reinforced with full basalt fiber was bending failure. Moreover, the results also indicate that the cracking load and ultimate bearing capacity of concrete composite beams reinforced with concrete-basalt fiber are lower than those of conventional concrete beam. This is mainly due to the interface between ordinary post-cast concrete and concrete reinforced with hardened basalt fiber. Due to the superior tensile properties of fiber, composite beams and all basalt fiber concrete beams exhibit a higher degree of ductility than conventional concrete beams. Utilizing the existing calculation theory for concrete beams reinforced with fiber, it was calculated that the cracking load and ultimate load of basalt fiber beams were calculated, and the calculation results were consistent with the experimental results. Based on the results of the evaluation and the theoretical analysis, this study proposes a finite element modeling method for basalt fiber composite beams. The results of the analysis were consistent with the experimental results of all investigated beams. The established model was employed in order to investigate the influence of shear span ratio on the shear performance of basalt fiber beams.

Improvement of performance of the RC beams using the longitudinal spiral reinforcements

PurposeThis study aims to investigate the effects of using circular spirals as the longitudinal reinforcing bars on the performance of the concrete beams subjected to four-point bending load.Design/methodology/approachThe effects of using circular spirals as the longitudinal reinforcing bars on the performance of the concrete beams subjected to four-point bending load are investigated in this study. Employing circular spirals as the main longitudinal reinforcement is a novel idea presented in this paper. In this regard, a finite element model of the beam with spiral longitudinal reinforcement was developed. After model verification, several configurations of concrete beams reinforced by longitudinal spirals were simulated under the four-point loading condition.FindingsObtained results showed that using the longitudinal spirals in place of the conventional longitudinal reinforcing bars can improve the bearing capacity of the concrete beam, but at the same time, increases its ductility unacceptably. In other words, the spirals reduce the initial stiffness of the beam significantly. To solve the problem, the authors decided to use the longitudinal spirals as the auxiliary bars added to the main conventional longitudinal bars in the beams. New gained results were satisfactory. By adding the longitudinal spirals to the conventional bars, not only the bearing capacity of the beam increases between 24% and 63%, but also the initial stiffness and ductility of the beam raises between 11%–29% and 3%–57%, respectively, in comparison to the corresponding beam reinforced with conventional longitudinal bars.Originality/valueEmploying circular spirals as the main longitudinal reinforcement is a novel idea presented in this paper.

Numerical simulation of cost-effective green high-ductility engineered cementitious composites based on meso-scale particle flow model

To promote the sustainable development of building materials and reduce their cost, the cost-effective green high-ductility engineered cementitious composites (ECC) was developed by using domestic low-cost polyvinyl alcohol (PVA) fibers, ordinary river sand and high-volume incorporation of fly ash (FA) and silica fume (SF). The effects of different river sand particle sizes, sand-binder ratio and water-binder ratio on the bending and tensile properties of ECC were studied. Meanwhile, the meso-scale particle flow model based on discrete element method (DEM) is used to simulate the multi cracking behavior of ECC under four-point bending load and uniaxial tensile load. This is a new application of particle flow model in ECC. Moreover, the distribution characteristics and temporal-spatial evolution law of the of micro-cracks in ECC are simulated by using the DEM. Further on, the distribution of the force chain of the ECC are analyzed, and the visualization of the force chain under bending and tensile load is realized for the first time. Simulation results show that the multi cracking behavior mainly occurs in the pure bending section under four-point bending load, and the micro-cracks under uniaxial tensile load is uniformly distributed on the sample surface. Meanwhile, the unstable fracture of the strong force chain arch is the essential reason for the ECC failure. The curves and failure patterns obtained by simulation is compared to experimental results to verify the effectiveness of the numerical model.