Cable Reinforcement Research Articles

Optimal selection of cable reinforcement for concrete 3D printed lattice beam

This paper presents the optimal selection of cable reinforcement for concrete 3D-printed lattice beam. It also addresses key challenges associated with interlayer bonding and flexural strength of 3D printed elements. Three different types of reinforcement including 1.6 mm and 2 mm diameter rebar, (R1.6 & R2) and 1.5 mm wire (W1.5) with seven strings were evaluated with different stand-off distances of 10–20 mm. The interlayer bonding and flexural strength were investigated to determine the most effective reinforcement configuration. Results show that W1.5 reinforcement exhibited higher interlayer bonding and flexural strength as compared with R1.6 and R2. Subsequently, the optimal reinforcement configuration (W1.5) was embedded in a concrete 3D-printed lattice beam. The lattice beam was structurally evaluated using four-point testing, demonstrating an ultimate load-carrying capacity of 49.01 kN with a mid-span displacement of 2.99 mm. Moreover, it exhibited flexural failure with no premature failures such as inter-layer delamination.

Continuity breakageof cableinorthotropic stay rope of rectangular cross-section

Purpose. Construction of an algorithm for determining a stress-strain state of a multi-layer stay rope of a rectangular cross-section with a broken reinforcing fiber. Methods. Analytical solution of an interaction model of parallel fibers connected by elastic material of a stay rope of rectangular cross-section in the event of reinforcing element breakage using methods of mechanics of layered composite materials with soft and hard layers. Findings. An analytical algorithm for determining a stress-strain state of a composite stay rope of rectangular cross-section with a damaged reinforcing fiber is constructed.An analytical method for determining a stress-strain state of a rope with a comprehensive consideration of structure, mechanical properties of components, layout of reinforcing fibers in a cross-section, in a presence of a broken fiber, is developed in a closed form.It is established that load unevenness on fibers is practically independent of the ratio of an amount of fibers and layers in a rope and their total amount, and the ratio of fiber placement spacing in layers and spacing of layers in case of fiber breakage in a stay rope cross-section. Scientific novelty. It is established that load unevenness on fiber does not depend on a ratio of an amount of fibers and amount of layers in a stay rope. Practical significance. The developed algorithm makes it possible to determine the share of tractive capacity loss of a stay rope of rectangular cross-section due to breakage of a reinforcing element. The known value of lost strength makes it possible to establish acceptable conditions for use of a rope of rectangular cross-section. It is advisable to give a rope a shape with less resistance to air pressure by reducing the amount of layers compared to the amount of fibers in layers. Damage to a corner element of cable reinforcement is more dangerous, it leads to a load increase of almost 30 % in the most loaded fiber, while the specified parameter is less than 20 % in case of a breakage of the central fiber.

Study on Reinforcing Anchor Cable Support in Overreach Section of Deep Roadway

With the increasing depth of coal mining, the conditions of deep working face are becoming more and more complex, the stability of surrounding rock of roadway is getting worse and worse, and the problem of deep roadway support is becoming more and more prominent. In this paper, the 24100 working face of Pingdingshan No.11 Coal Mine is taken as the engineering background. In view of the problems of roof crushing and deformation and more net pockets in the return airway affected by the mining of the working face, the grouting anchor cable reinforcement and support technology in the advance section of the deep mining roadway is proposed, and the feasibility of the support effect is verified by numerical simulation. The results show that the influence range of the advance abutment pressure of the air roadway is about 60 m, and the reinforcement support strength required for the roof of the roadway is 50.6 kN/m2. The grouting anchor cable reinforcement support technology system of the return air roadway can control the deformation of the surrounding rock of the roadway and achieve safe and efficient mining.

“Shoe Shop” Lacing Technique: A New Biceps-Augmented Knotless Suture for Arthroscopic Rotator Cuff Repair

Advancements in rotator cuff tear repair have led to innovative techniques for complex cases. In this article, we introduce the “shoe shop” lacing technique, a knotless, side-to-side, and tendon-to-bone suture method augmented with the long head of the biceps tendon (LHBT) for anterior margin–deficient massive rotator cuff tears. This approach offers simplicity, durability, and potential advantages in biomechanics. The LHBT integration and knotless sutures make it a promising solution for challenging tear patterns. This technique provides an attractive option for arthroscopic repair, improving outcomes in cases where anterior cable reinforcement is essential.

The buildability and flexural properties of 3D printed recycled mortar reinforced with synchronized steel cable under different reinforcement ratios

This study achieved the synchronized reinforcement of 3D printed mortar with steel cables by modifying the printing equipment. Recycled sintered brick powder replaced 30 % of cement in the 3D printed mortar mixture. The optimal range for the open time was determined through flowability tests and preliminary tests, which ranged from 10 to 40 min. Ways to improve the reinforcement ratio without compromising buildability were explored. The bond strength between the steel cables and the printed mortar was tested and found to be approximately 2–2.5 MPa. The flexural strength of the printed beams with steel cable reinforcement increased by 172%–357 %, and multiple cracks occurred at the mid-span during the failure process. A correction formula for the flexural strength was provided, with calculated values showing an error within 12 % of the test values.

Surrounding Rock Deformation Mechanism and Control Technology for the Roadway in the Fault-Disturbed Zone under Special-Shaped Coal Pillars

In order to explore the impact of residual special-shaped coal pillars and fault disturbances on the lower layered roadway, this study takes the short-distance coal seam mining in Luwa Coal Mine as the engineering background to explore the surrounding rock deformation mechanism along the mining roadway in the fault-disturbed zone under special-shaped coal pillars, it presents the roadway surrounding rock control technology and it conducts on-site industrial test verification. The study shows that the abutment pressures on the floor of special-shaped coal pillars are distributed as “three peaks and two ridges”. The part beneath coal pillars is mainly disturbed by vertical stresses, while the part below the coal pillar edge is co-affected by vertical stresses and shearing stresses, generating a stress concentration coefficient ranging from 1.26 to 1.38 in the lower coal seam. According to the superposed effects of special-shaped coal pillars and fault disturbance on the mining roadway, the mining roadway is divided into the lower section of goaf, the section crossing the coal pillar edge, the lower section of coal pillars, and the section obliquely crossing the coal pillar edge. According to the above sections, the segmental control strategies of “improving stress distribution on surrounding rock + reinforcing support on special sections” are proposed. A joint control technology of large-diameter drilling hole pressure relief and special section anchor cable reinforcement support was adopted to carry out on-site industrial testing and monitoring. Overall, the convergence rate on the roadway surrounding rock is controlled within 5%, and the deformation of roadway surrounding rock is under effective control.

A novel asymmetric stress unloading technology in two sides of coal roadway in deep mine: A case study

The existing stress unloading technology using dense equal-diameter large drilling usually results in damaging the load-bearing structure of the shallow surrounding rock of the roadway. Therefore, this study, while providing full anchor cable strong anchorage support for the roadway sides, proposes an asymmetric stress unloading technology on the two sides of a coal roadway. Small-diameter holes are directly drilled in the shallow low-stress area, and the large-diameter stress unloading hole (LSUH) is excavated in the deep stress concentration peak area for the right side of the roadway; utilizing the floor rock roadway, by drilling upward through the rock stratum, excavating the LSUH in the deep stress concentration peak area for the left side of the roadway. Full anchor cable reinforcement technology for the shallow surrounding rock of roadway sides forms a thick layer anchorage load-bearing structure, avoiding cracks further development of the shallow coal seam of the roadway side and creating a quality stress environment for the implementation of the LSUH in the deep area of the roadway side. The small drilling and the coal slag discharge of the roadway left side does not pass through the shallow anchorage area of the roadway left side, and the shallow small drilling on the roadway right side is supported reinforcement by the steel pipe, which minimize the impact of hole-manufacturing on the shallow anchorage area to the greatest extent possible. Large-diameter weak structural stress unloading holes are arranged in the deep stress concentration peak area of far away from anchorage area of the roadway side, making the high concentration stress areas around the roadway be transferred to deeper area without affect the stability of the shallow anchorage area, also making the plastic deformation of the surrounding rock in the stress concentration area of the roadway side be transferred to the weak structural area of the stress unloading holes. A numerical model for the asymmetric stress unloading technology on the two sides of a coal roadway is established to investigate the influence of different stress unloading parameters on the roadway side stress. Engineering practice shows that this technology can ensure the long-term stability of the roadway.

Numerical Investigation on the Yield Pillar Bearing Capacity under the Two-End-Type Cable Reinforcement

For underground coal mining techniques such as gob-side entry retaining (GER) or gob-side entry driving (GED), the stability of yield pillars is paramount. A well-designed yield pillar aims to withstand mining-induced stresses. This study delves into the impact of bi-terminal cable support on the stability of such pillars. Utilizing 30 distinct numerical models, each with varying pillar width/height (w/h) ratios and diverse cable support methodologies, our findings suggest an upward trend in both peak and residual strength in response to heightened support strength. Notably, pillars with a wider configuration exhibited a more pronounced increase in peak strength compared to their narrower counterparts, while the latter showcased a more pronounced residual strength enhancement. Additionally, the residual/peak strength ratio was smaller in narrower pillars and increased with the increase in the cable support strength. In view of the surrounding rock mass’s support stress distribution, numerical modelling was adopted to analyze the underlying support mechanism. The results showed the support stress zones extended farther on both sides of pillars with the decrease in the row spacing, which made the radial stresses rise effectively and ameliorated the coal pillar’s stress state. Finally, with the 8311 operation advancing towards the station, the deformation amplitude of the coal pillar was only 2.28%, and the stability of the coal pillar was effectively maintained.

Study on failure behaviors and control technology of surrounding rock in a weakly cemented soft rock roadway: A case study

During coal mining, the deformation and failure of a weakly cemented soft rock roadway roof could cause difficulties for roadway support. In this paper, a combination of on-site measurement and theoretical analysis is used to solve this issue. Firstly this paper investigates the in situ deformation and failure behaviors of a soft rock roadway in a mine in Western China. Then, the failure mechanism and corresponding support principles are discussed and given. Third, various support schemes (bolt and cable reinforcement optimization, grouting, and single prop + top beam combined reinforcement) are proposed and tested. Results show the support capacity can meet the requirements after optimizing the bolt and cable reinforcement support. Due to the development of roof cracks and low grouting pressure, the grouting slurry did not completely fill the roof cracks, resulting in a poor roof control effect. The passive support of a “single prop + top beam” can effectively control the roof subsidence and achieve good application results.

Deformation Analysis of the Cable Reinforcement System of Large Section Box Culvert Roof Entry and Downward Penetration

For the underpass railway large-section box culvert jacking and pipe jacking project, the key to ensuring the normal operation of the existing railway is to maintain the smoothness and stability of the track, railway settlement monitoring and line reinforcement, and box culvert and pipe culvert attitude control are the keys to solving this problem. Taking the Beijing-Harbin high-speed railway project under a city road in Beijing as an example, the law of railway track settlement during the implementation of box culvert jacking was analyzed according to real-time monitoring data. The monitoring results show that accelerating the pouring of the bedding and grouting and strengthening the railway subgrade on both sides of the foundation pit can effectively control the settlement of the railway subgrade and reduce the impact of subsequent construction on the railway, and the line renovation and secondary grouting reinforcement can effectively improve the smoothness of the railway. Combined with the comparative analysis of numerical simulation results, the necessity of line refurbishment and rail fastening combination reinforcement in actual construction is verified.

Destabilization Mechanism and Stability Control of the Surrounding Rock in Stope Mining Roadways below Remaining Coal Pillars: A Case Study in Buertai Coal Mine

To study the stability control of stope mining roadways below remaining coal pillars, the present study investigates the destabilization mechanism of coal pillars and roadways in sections under the dual action of supporting pressure on the floor of the remaining coal pillar in the overlying coal seam and the mining at the working face of the lower coal seam and clarify the principle of surrounding rock stability control based on theoretical analysis, numerical simulation, and industrial testing. The results yielded the following findings. After the stope mining of the overlying coal seam working face, the stress transfer of the T-shaped remaining coal pillar significantly increased the vertical stress of the lower coal seam. The lateral support pressure generated by the stope mining at the lower coal seam working face further aggravated the stress concentration in the coal, leading to severe compression-shear failure of the surrounding rock. As the sectional coal pillar becomes wider, the roadway gradually avoids the area of peak superimposed support pressure. The vertical stress curve of the sectional coal pillar shifts from single-peaked to asymmetrically double-peaked, and the stress difference between the two roadway ribs and the stress concentration coefficients decrease continuously. A stability control method of long anchor cable reinforcement support is proposed. In-situ industrial testing showed that the surrounding rock deformation was basically stable during the service period of the 42202 stope mining roadway, thus achieving the stability control of the stope mining roadway.

Comparative study and optimal selection for different cable-stiffened latticed shells

The cable-stiffened latticed shell can be constructed in varied structural forms by diverse types of single-layer latticed shells and cable-strut systems. So, to provide references for model selection, this paper studied the efficient combination of latticed shells and cable-strut systems in different boundary conditions and proposed a performance evaluation method. The general modeling process was illustrated firstly, and several new structural forms with folded curved surfaces were proposed. Then, based on the improved equilibrium matrix theory, the force-finding analysis was carried out for the initial state, which can guarantee actual mechanical properties in the numerical model. Thus, the overall stiffness, the bearing capacity, and the cable reinforcement effect were obtained through the nonlinear stability analysis. And for the optimal selection from multiple structural forms, AHP-TOPSIS was used to judge the latticed shell system for the first time. The comprehensive structural performances were evaluated and ranked by this multi-attribute decision-making method. Finally, the results showed that the complicated cable-strut system could not necessarily lead to higher structural efficiency. Regardless of the cable-strut layouts, the spherical cable-stiffened latticed shell had a high bearing capacity when the ribbed grid was adopted. For the cylindrical structure, the folded latticed shell divided by orthogonal grids maximized the role of in-plane cables and was considered the best choice.

CALCULATION METHODS OF MONOLITHIC REINFORCEDCONCRETE STRUCTURES WITH POST-TENSION REINFORCING ROPES

In Ukraine, the use of "post-tensioning" technology, which consists in the use of monolithic structures with pre-tensioned ropes, is growing. Domestic construction practice uses the term "prestressed reinforced concrete structures with tension of cable reinforcement on concrete." Post-tensioning technology is a modern approach to construction that allows you to create monolithic structures with great strength and stability. Its main advantage is the use of pre-tensioned ropes, whichprovide additional structural strength.In this article, the main methods of calculating such monolithic reinforced concrete structures are presented and the experience of using this technology in the construction of public buildings in Ukraine is presented.The use of prestressed reinforced concrete structures with the tension of cable reinforcement on concrete has numerous advantages. They are more durable, resistant to deformations and able to support large loads. Such structures are used in the construction of bridges, overpasses, high-rise buildings and other industrial and civil structures.Ukraine is increasingly adopting modern and efficient construction methods, which is confirmed by the increased use of this technology. This helps to improve the quality and reliability of building structures, and also ensures optimal use of materials and resources.In general, the article aims to promote the popularization, study and development of monolithic structures with pre-tensioning of cable reinforcement on concrete, as well as the creation of an appropriate regulatory and legal environment for their design and construction. This will help improve the quality and safety of building structures and ensurefurther progress in the construction industry of Ukraine.

Bi-criteria stability evaluation approach of gravity dam with pre-stressed cable reinforcement

Bi-criteria stability evaluation approach of gravity dam with pre-stressed cable reinforcement

Stability Analysis of Rock Slope with Multilayer Weak Interlayer

The existence of the weak interlayer of the rock slope changes its mechanical characteristics. To ensure the safety of the slope, it is necessary to analyze the overall stability of the slope. Taking the double-layer weak interlayer rock slope beside 318 National Road in Qiyue Mountain, Hubei Province, as an example, a slope model with a weak interlayer was established through GTS software, and the model was imported into FLAC3D for calculation, and the deformation of the slope by the double-layer soft interlayer was studied. The influence of characteristics and safety factors reveals the controlling effect of the double-layer weak interlayer on the stability of the slope and its failure mode. The potential sliding surface of the slope is determined to be the lower weak interlayer, and the weak interlayer after the anchor cable reinforcement is carried out. Numerical analysis shows that the reasonable application of anchor cables significantly improves slope stability. The research results can provide reference significance for slope stability analysis of similar projects.

Analytical Solution for the Deformation and Support Parameters of Coal Roadway in Layered Roof Strata

In order to meet the security and high-efficiency production needs, high-strength bolt (cable) reinforcement technology is usually used to maintain the stability of roadways. However, due to the great variability of lithology and mechanical properties, the failure form and stability of the layered roof in coal roadways are significant differences. The traditional supporting design method of the layered roof support in coal roadways is the engineering analogy method, which depends on experiences rather than theoretical analysis. Based on the theory of the elastic foundation beam and key stratum, this paper establishes a simplified analytical model of layered roof strata in coal roadways. Based on the Mohr-Coulomb theory, this paper gives the failure criteria of the layered roof strata, and the failure range of the layered roof strata is obtained. The length and pretightening force of bolt (cables) of the layered roof strata can be calculated based on the suspension theory and composite beam theory, which providing a quantitative theoretical basis for the determination of supporting parameters. Finally, as a case, the layered roof strata failure range and supporting parameters of the S1301 auxiliary transportation roadway in Gucheng coal mine are calculated.

Research on the Reasonable Strengthening Time and Stability of Excavation Unloading Surrounding Rock of High-Stress Rock Mass

This study is aimed at better understanding the deformation and failure mechanism of surrounding rock during excavation unloading of a high-stress rock mass and determining the reasonable reinforcement time for the surrounding rock. To fulfill this aim, true triaxial tests were carried out on different loading and unloading paths during the unilateral unloading of a high-stress rock mass. The variational condition for minimization of plastic complementary energy is obtained, the optimal reinforcement time is determined, and the range of the plastic zone in the surrounding rock reinforced by anchor mesh-cable-grouting is compared and analyzed. The results are as follows: (1) Based on the Mohr-Coulomb yield criterion and the deformation reinforcement theory of surrounding rock, the stable state with the minimum reinforcement force is obtained. (2) After the true triaxial tests on the unilateral unloading of the third principal stress were carried out under different confining pressures, loading continued to be performed. Compared with rock failure without confining pressure, in the conventional uniaxial compression test, the failure of samples is dominated by composite splitting-shear failure; the unilateral unloading stress-concentration failure is a progressive failure process of splitting into plates followed by cutting into blocks and then the ejection of blocks and pieces. (3) The relationship between the time steps of the surrounding rock stability and the excavation distance is obtained. The supporting time can be divided into four stages: presupport stage, bolt reinforcement stage, anchor cable reinforcement stage, and grouting reinforcement stage. (4) In the range of within 5 m behind the tunneling face, the plastic zone of the surrounding rock with support is reduced by 7 m as compared with that with no support. In the range of over 5 m behind the tunneling face, the plastic zone of the roadway floor with support is reduced by 2.6 m as compared with that without support, and the deformation is reduced by 90%. These results can serve as a reference for controlling the behavior of surrounding rock during excavation unloading of high-stress rock masses.

Three‐Dimensional Physical Simulation and Control Technology of Roof Movement Characteristics in Non‐Pillar Gob‐Side Entry Retaining by Roof Cutting

An overlying rock structure plays a key role in controlling the roof deformation of nonpillar gob‐side entry retaining by roof cutting. On the bases of the actual geological conditions of II 632 Haulage Roadway at the Hengyuan coal mine, a similar three‐dimensional simulation experiment of roof precutting is conducted. Thereafter, the caving characteristics and migration law of the roof strata in the strike and dip directions are obtained. Moreover, the roof of the retained roadway and key strata of the goaf can form a hinge structure of the key blocks. By monitoring the deformation of the surrounding rock and stress distribution of the roof, the skew deformation characteristics of roadway roof are obtained. By observing the borehole peeping technology, the roof subsidence near the goaf is determined to be greater than that of the solid coal side, and the roof subsidence of the gob‐side entry retained by roof cutting is greater than that of the floor heave and two sides approaching. Results of the three‐dimensional similar simulation experiment indicate that the mechanical structure model of the key block of the retained roadway roof is constructed, and the mechanical analytical solution of the required support resistance of the retained roadway roof is obtained. This study proposes the constant resistance and large deformation anchor cable reinforcement support method to control the roof deformation of the retaining roadway. Through engineering application, the maximum value of the roof and floor movement of the retained roadway is stable at approximately 650 mm. The retained roadway can meet the demand of the next mining face.

The effect of eccentricity on the strength characteristics of glued rods made of steel cable reinforcement in solid wood

The article is devoted to the study of the behavior of glued rods made of hot-rolled steel reinforcement and steel cables in a solid wood based on experimental tests of beam elements. The influence of eccentricity on the deformation - strength characteristics is studied with a straight-line gluing of reinforcing rods. The comparative analysis of the deformability indices of the centered and lateral gluing performed by milling with fillet groove U - shaped milling cutters was carried out. The technology of manufacturing samples, which consists of preparing wood, milling and pasting rebar into the groove, were described. The diagrams of deformation - strength characteristics of samples of various types were obtained and correlated. The conclusions were drawn about a local increase in strength in the case of using a steel cable as reinforcement and the negative effect of eccentricity on the strength of the adhesive joint during tensile tests. A visual analysis of the damage occurring during the test showed that in the manufacture of full-scale structures, glued rods should be closed with an array of wood. The conclusions were drawn about the optimal depth of milling of grooves for reinforcement, taking into account the use of adhesive compositions on epoxy resin filled with quartz sand - 1.5 depth of reinforcing bar diameter.

Out-of-plane reinforcement of masonry walls using joint-embedded steel cables

The out-of-plane mechanism (rocking) of walls often causes fatalities and collapses of historic buildings during earthquakes. This paper addresses the problem of assessing the seismic resistance of walls subjected to out-of-plane bending, before and after reinforcement. A new retrofitting method, consisting in the use of high-strength steel cables fully embedded in the mortar bed joints was studied. An experimental investigation using full-scale brickwork specimens was therefore conducted in an attempt to assess the walls’ structural response when these are subject to out-of-plane loads. Test results demonstrated that it is possible to increase the out-of-plane capacity with the proposed method. A simplified macro-element procedure is also presented along with recommendations for the calculation of the walls’ capacity before and after the application of the steel cable reinforcement. Predictions of the magnitude of horizontal force required to cause out-of-plane failure using the proposed procedure and quasi-static analysis procedures are compared with the results of laboratory experiments.