Research on flexual calculation theory of reinforced concrete t-beam strengthened by steel wire mesh and polyurethane cement (SWM-PUC) composite

In order to solve the problem of poor bonding and easy peeling of reinforced concrete structure strengthened by steel wire mesh and polymer mortar (SWM-PM). In this paper, a steel wire mesh and polyurethane cement (SWM-PUC) composite strengthening technique is presented. The flexural properties of one unreinforced beam, two SWM-PM strengthened beams and four SWM-PUC composite strengthened beams were studied experimentally. The experimental results show that the SWM-PUC composite reinforcement layer can improve the load carrying capacity and rigidity of reinforced concrete beams and limit the unfolding cracks significantly. The SWM-PUC composite strengthened beams have pure bending damage and peeling damage between the strengthening layer and the concrete has not occurred. However, SWM-PM strengthened beams with the same SWM reinforcement ratio occurred with peeling damage between the reinforcement and the concrete. On basis of an experimental study, the theoretical formulas for cracking load, ultimate load, deflection and width of crack of SWM-PUC composite strengthened beams are proposed by the simplified stress-strain constitutive relation of the material and the theoretical formulas are deduced with the code. By contrasting the test results with the theoretical computation results, the accuracy of the experiment results and the reliability of the theoretical formulas were verified. Received:                                         21.10.2024 Received in revised form:              09.04.2025 Accepted:                                         17.06.202

Effect of tangent and secant elastic constants on CCBO stress evaluation in transversely isotropic rock

The Compact Conical Borehole Over-coring (CCBO) method is employed for the determination of the three-dimensional stress state in rock environments. The method utilises a strain gauge cell to quantify the deformation of over-cored rock, the deformation characteristics of which are evaluated in the laboratory. It is assumed that the in situ rock material is homogeneous, elastic and transversely isotropic and it is, therefore, imperative to ascertain the deformation parameters of the transversely isotropic material present in situ. The tangent and secant deformation parameters were taken from previous research and then employed throughout the stress determination process. This paper outlines the fundamental principles of the method and presents results from practicalmeasurements carried out at the Grimsel Underground Research Laboratory in Switzerland. The stress results vary depending on whether alternative deformation characteristics (i.e. tangent or secant) are taken into account during the evaluation process

Assessment of electrical dyssynchrony using 12-lead ECG: A comparative analysis of proposed metrics

Cardiac resynchronization therapy (CRT) represents a well-established therapeutic strategy widely implemented in the treatment of patients with heart failure. By addressing electrical dyssynchrony, CRT improves mechanical cardiac function and reduces the risk of heart failure-related hospitalization. Current guidelines suggest QRS duration and left bundle branch block morphology for assessing electrical dyssynchrony. However, 30% of CRT patients do not respond to the therapy. This paper reviews the alternative metrics of electrical dyssynchrony derived from standard 12-lead ECG for patient selection and/or pacing programming in CRT. Specifically, a detailed analysis of recently proposed parameters of electrical dyssynchrony to elucidate whether they offer advantages over the currently used criteria was performed

Screening young adults\u27 health using non-invasive methods

Monitoring the health of young adults is essential for identifying potential risks and promoting long-term well-being. This study aimed to assess physiological and anthropometric parameters in 100 young adults (mean age 22.25 ± 0.46 years) using non-invasive methods, including ECG, blood pressure, BMI, and body composition analysis (muscle mass, body fat percentage, and visceral fat). A structured questionnaire collected demographic and lifestyle data, including physical activity and dietary habits. Participants were classified as athletes (42%) and non-athletes (58%) to examine the influence of regular physical activity on health indicators. Results showed that 74% of participants had a normal BMI, with 13% overweight and 13% obese. Elevated visceral fat was found in 12% of respondents, and total body fat was higher in non-athletes compared with athletes. Men had higher visceral and total body fat values, while athletes demonstrated greater muscle mass. ECG analysis revealed sinus bradycardia more frequently among athletes, as well as differences in PQ and QTc intervals, indicating the influence of regular exercise on cardiac electrophysiology. Following physical exertion, systolic blood pressure and heart rate significantly increased in both groups, confirming a normal cardiovascular response to exercise. Overall, regular physical activity was associated with healthier body composition and physiological cardiac adaptations, emphasizing its preventive role in reducing obesity and cardiovascular risk among young adults

Negative Moment Zone in UHPC-Strengthened Simply-Supported-to-Continuous Concrete Box Beams: Cracking Resistance Analysis

In this study, to investigate the cracking resistance of UHPC-strengthened simply-supported-to-continuous concrete box beams in the negative moment zone, a total of nine specimens were designed: one reinforced concrete box beam (comparison beam), seven UHPC-RC composite box beams (reinforced beams), and one prestressed concrete box beam (prestressed beam). The research focuses on evaluating the influence of key parameters—including reinforcement ratio, UHPC casting length in the negative moment zone, UHPC thickness, and the joint configuration between UHPC and ordinary concrete—on the cracking resistance of these beams. The results demonstrate that, under the same reinforcement ratio, UHPC strengthening in the negative moment zone significantly enhances the cracking performance of the test beams, with the cracking load increasing by 46%. As the UHPC casting length increases, the maximum crack width at the vertical interface between the full normal concrete (NC) section and the UHPC-NC composite section decreases markedly. Additionally, increasing the UHPC thickness leads to a substantial reduction in the maximum crack width at both the UHPC-NC composite section and the intermediate diaphragm section. Received:                                   28.05.2025Received in revised form:       21.01.2026Accepted:                                  19.03.202

Flexural analysis of steel mesh reinforced polyurethane concrete material

In this paper, a new method of steel mesh reinforced polyurethane concrete (SMPUC) material for bridge reinforcement is proposed because of the peeling failure of the reinforced layer of steel mesh reinforced polymer mortar (SMPM) material. Using the excellent anti-corrosion and tensile properties of high-strength steel mesh, as well as the advantages of strong adhesion and fast curing speed of polyurethane concrete, the two materials are combined together. In order to verify the feasibility of this strengthening method, the mechanical properties of SMPUC material are investigated by bending test of SMPUC material sheet. The main factors affecting the tensile properties of the composites are analyzed by considering the test variables such as specimen width, specimen thickness, glue-powder ratio and curing time. Based on the simplified tension model of high strength steel wires and the stress-strain relationship between tension and compression of polyurethane concrete, the calculation method of flexural bearing capacity of composite materials is obtained. The test results show that the flexural strength of the composite can be improved by increasing the width of the specimen, and the deflection can be reduced by increasing the reinforcement ratio, while the influence of the glue-powder ratio on the deflection is small. Received:                               07.10.2024 Received in revised form:     16.12.2024 Accepted:                               15.01.202

Effect of fibers on self-healing properties of microbial mineralized cement mortars

In this study, we selected cement mortar as the research object, used the expanded perlite (EP) which adsorbed bacteria as the self-healing agent, and mixed basalt fibers to improve the properties. The effects of different dosages and sizes of self-healing agent and basalt fibers on the mechanical properties and self-healing properties of cement mortar were investigated by compressive strength, SEM, EDS, XRD, and optical microscopy tests. The results of the study showed that the bacteria were able to survive in cement mortar using expanded perlite as a carrier and induced the generation of calcium carbonate precipitates to fill the cracks. The dosage of the healing agent is proportional to the amount of healing products generated, which can significantly improve the self-healing performance of cracks in mortar. Fibers can bond the material, play the role of bridging, and become the adsorption carrier of bacterial metabolic precipitates, which is beneficial to the dense bonding of the products. The addition of appropriate amount of basalt fiber can simultaneously improve the self-healing properties and compressive strength of mortar. The simultaneous addition of healing agent and basalt fiber can realize the complementary advantages. By adding a small amount of healing agent and a moderate amount of fiber, not only can achieve 100% self-healing performance, but also improve the compressive strength of mortar. This study provides useful theoretical guidance for the design, preparation, and application of concrete. Received:                               10.09.2024 Received in revised form:     30.12.2024 Accepted:                               12.03.202

Research on seismic resistance of combined system bridge of cable-stayed bridge and irregular arch

Bridges are prone to damage during earthquakes, with large-scale or complex structural systems being particularly sensitive to seismic impacts. Taking the bridge that integrates a cable-stayed bridge with a backless slanted tower and a lower-supported irregular arch bridge as the background, this paper establishes a spatial analysis model for Xiangfeng River Bridge using the finite element software Midas Civil. Based on the concept of structural vibration control design, the concept of time-history response influence factors is introduced to conduct a time-history response parameter analysis of the structure. The study investigates the effects of wind brace arrangement, concrete elastic modulus, length of arch rib concrete sections, and the inclination angle of the pylon on the seismic performance of the bridge. It further compares and analyzes structural vibration control and damping, conducts structural seismic checks, and performs elasto-plastic time-history response analysis at the consolidated positions of the tower, beam, and pier by defining elasto-plastic materials and fiber hinges. The research results indicate that the sensitivity of the overall seismic performance of the structure to different parameters follows the order from strongest to weakest as: pylon inclination angle > length of arch rib concrete sections > concrete elastic modulus > wind brace arrangement. “K”-shaped wind braces are more conducive to structural seismic resistance compared to parallel wind braces, and omitting wind braces will significantly impact the seismic performance of the structure. Increasing the short length of the arch rib concrete sections affects the structural spatial mass distribution and reduces the overall lateral stability of the structure.   Received:                                           26.06.2025 Received in revised form:                10.09.2025 Accepted:                                           24.11.202

Numerical study on the TBM mucking performance in EH project and optimization of the supporting ribs

To study the cutterhead’s muck transfer performance of the TBM applied in EH project, China, a discrete element method (DEM) based numerical model was built and the mucking process was simulated at different penetration rates and cutterhead rotational speed. It is found that the conventional straight-supporting-rib cutterhead performed well at different penetration rates and low RPMs, but the muck excessive-thrown problem was serious when the RPM was higher than 10 rev/min. To overcome this problem, a new arched-supporting-rib cutterhead was proposed. The curvature radius of the arched supporting ribs is suggested between 1.25 m and 1.75 m, and the offset angle is suggested between 40° and 45°. The newly proposed arched-supporting-rib cutterhead can performed well in muck transfer at a greater RPM range of 4~13 rev/min, which allow the TBM to excavated at low, medium and high RPMs considering ground conditions and requirement of construction progress. Received:                                         22.10.2024 Received in revised form:              04.04.2025 Accepted:                                         22.05.202

Calculating the dynamic disturbances of weapon systems on unmanned ground vehicles

This paper investigates the dynamic disturbances affecting weapon systems mounted on unmanned ground vehicles (UGVs), which pose a significant challenge in maintaining aiming accuracy when moving across uneven terrain. These disturbances arise from terrain-induced vibrations, complex hull movements, suspension-induced vibrations, and cross-inertial interactions between the gun barrel and the turret, particularly under asymmetrical road excitations. This research aims to develop a comprehensive mathematical model describing the dynamic disturbances caused by mass imbalances and cross-inertial effects in weapon-UGV systems and to analyse the influence of asymmetrical and non-uniform road surfaces on weapon system vibrations. The proposed nonlinear dynamic model is constructed using Euler rotation matrices and coordinate transformation methods, incorporating suspension-induced disturbances. An uneven road model with varying roughness heights between the left and right sides and asymmetrical profiles was introduced, including sequential semi-sinusoidal, trapezoidal, and rectangular ridge shapes to represent battlefield-like terrain conditions. The governing equations were solved in MATLAB-Simulink to evaluate weapon vibrations, angular deviations, and disturbance torques. The simulation results showed that asymmetrical road excitation significantly amplified the disturbances to the weapon system during aiming. A scaled UGV model was used to conduct experiments on vehicle body vibrations while moving over a rough terrain section, assessing the effect of suspension and uneven road surfaces on the weapon system. The results demonstrate that the developed dynamic disturbance model provides a solid basis for future stabilisation and compensation control strategies. It improves the firing accuracy of weapon systems mounted on unmanned ground vehicles operating in real-world conditions