Bar Model Research Articles

Development and Validating the Number and Mathematical Operations Problem-Solving Framework in the Form of Higher Order Thinking Skill (HOTS) through Bar Model Strategy - A Fuzzy Delphi Methods

This study was conducted to develop and obtain the expert consensus using Fuzzy Delphi Method (FDM) on the Number And Mathematical Operations Problem-Solving Framework (NMOPSF) in the form of HOTS through Bar Model Strategy. NMOPSFthrough Bar Model strategy is developed as an important guide for pupils in solving HOTS problem-solving questions in Mathematics. Through FDM, the process of obtaining expert consensus was carried out on two stages. The first stage is a structured interview administered to 7 experts in Mathematics education to identify the components in the NMOPSFthrough Bar Model strategy. On the second stage, the consensus of 15 experts in Mathematics education was obtained using a 7-point Likert scale questionnaire. The interview conducted has identified four main components in NMOPSFthrough Bar Model strategy, namely Concept, Procedure/Algorithm, Representation and Strategy, two special components, namely the Value and ICT (Cybergogy) and two items namely Polya Model and the Bar Model Strategy. From the research conducted, it is found that all the components and items for the NMOPSFthrough Bar Model strategy have met the three main conditions of FDM which is the threshold value (dconstruct) ≤ 0.2, the percentage of expert group consensus ≥ 75% and the value of α-Cut (Fuzzy score) ≥ 0.5. These findings suggest that all the components and items for the NMOPSFthrough Bar Model strategy are necessary to help Year Five pupils solve HOTS problem-solving questions in Mathematics well.

Development Of Self-Use Module For The Problem-Solving Framework Of The Number And Mathematical Operations In The Form Of Higher Order Thinking Skill (HOTS) Using The Bar Model

The curriculum transformation implemented in the Malaysian Education Development Plan (PPPM) 2013-2025 PPPM emphasizes the concept of high-order thinking skills (HOTS) applied in Mathematical problem-solving skills. However, it is seen to surprise the pupils and was not handled well. The level of achievement of the majority of the pupils in this country in Mathematics is still unsatisfactory. Pupils have difficulty getting good performance in Mathematics especially in public examinations in Malaysia. The mathematical problem-solving framework in the form of HOTS (KP2MK) using the Bar Model strategy that has been developed is seen to help overcome this problem. Therefore, this self-use module developed to ensure that KP2MK using the Bar Model strategy can be used optimally. It can be used as a guide for teachers and pupils in applying KP2MK using the Bar Model strategy in the teaching and learning (TnL) process in the classroom. The self-use module of KP2MK using the Bar Model strategy has been developed based on the Sidek and Jamaludin Module Development Model (2005). This self-use module has obtained validation from 5 experts in the field of Mathematics education. To ensure it has high reliability, a pilot study was conducted involving 35 pupils. The findings indicated that this self-use module has good content validity of 93% (content validity coefficient > 0.70) and good reliability (Cronbach's Alpha coefficient value = 0.96). The implications of the study show that this self-use module definitely can be used as a guide for teachers and students in applying KP2MK using the Bar Model strategy optimally in the TnL process in the classroom.

An investigation of fatigue behavior and residual strength model of steel-GFRP composite bar

Steel-fiber reinforced polymer (FRP) composite bar (SFCB) combines the advantages of corrosion resistance of FRP and good ductility of steel, and is a promising reinforcement material to improve the service life of marine structures. However, the fatigue behavior of SFCB is complex and has not been explored. Therefore, in this study, fatigue tests were conducted at different stress levels (0.32, 0.36, and 0.41 of quasi-static tensile strength with a fixed stress ratio of 0.1) and tensile tests were performed after fatigue pre-damage for a certain number of cycles (25%, 50%, and 75% of the fatigue life) to investigate the fatigue behavior of SFCB. The results show that fatigue failure is caused by steel core fracture, and the FRP layer can improve the fatigue life. Compared with the change of residual strength, the stiffness degradation of SFCB during fatigue loading was not significant. Finally, a residual strength prediction model containing known parameters of the S-N curve is also proposed, which can well predict the residual strength decay of SFCB after fatigue damage. In conclusion, these findings and the proposed residual strength prediction model contribute to the understanding and design of SFCBs.

Management of Lingual Cortex Fracture of Mandible Using Lingual Arch Bar: A Finite Element Analysis of Reduction with a Pilot Clinical Trial.

Fractures of lingual cortex are frequently left untreated leading to poor resolution of patient's symptoms and function. Positioning an implant on same side of fracture would provide better reduction. The study aims at improving stability offered by Erich arch bar placed on lingual surface, by Finite element analysis (FEA) along with a pilot clinical trial. Two FEA models were generated from CT scan of an individual having lingual cortex fracture: control model with labial arch bar and study model with lingual arch bar. Parameters assessed: Stress distribution (Mpa) along lines of osteosynthesis; Separation of fracture fragments (mm) across fracture line. Associated, was a clinical trial of 5 patients, managed by placing lingual arch bar. Feasibility of arch bar, post-operative pain, radiographic inter-fragmentary gap and complications were assessed clinically. Lingual positioning of arch bar demonstrated less displacement (mm) of fracture fragments compared to labial placement (0.123 vs. 0.677) upon application of masticatory load. Insignificant lingual splay and lesser degree of stress distribution (Mpa) was observed (83.1 vs. 99.3) favoring placement of arch bar on lingual side. Clinical trial correlated with outcomes of FEA, resulting in improvement of patient's symptoms. FEA and supporting clinical trial provided an effective method of reduction for lingual cortical fracture.

Dynamic strength characteristics of fractured rock mass

Fractures play crucial role in the behavior of rock masses, yet the understanding of their natural distribution and impact on dynamic characteristics remain unclear. Here the effect of “natural” fractures on the dynamic impact strength of rock mass was investigated using numerical specimens with fractures prepared using the Split Hopkinson Pressure Bar (SHPB) model. These fractures were generated through biaxial compression simulation. Various axial stress levels and confining pressures replicated diverse natural rock fracture distributions. To capture the anisotropic distribution of fractures in natural rock and the randomness of impact direction, impact from 0°, 90°, 180° and 270° directions were imposed. The biaxial loading simulation showed that fracture increases with higher loading stress, and rapidly expands in the post-peak stress stage, with ∨ or ∧ shaped slip plane depending on confining pressure. The impact strength of the fractured specimen decreases as the number of prefabricated fractures increases, following a two-stage pattern, i.e., rapidly decrease with small number of fractures and gradually decrease with high number of fractures. Pre-existing fractures aligning with the impact direction provide stronger resistance compared with fractures deviated, and their location and distribution significantly affect the stress transmission. The impact from other directions has different stress transmission routes related to the fracture and macroscopic surface distribution. Importantly, a specimen’s loading history shapes its internal fracture distribution, thereby affecting its resistance to impact stress. This research provides invaluable insights into the role and mechanics of fractures in rock masses, thus enhancing our understanding of rock dynamics and potentially informing more effective geotechnical engineering practices.

Study on Stability of Elastic Compression Bending Bar in Viscoelastic Medium

In the southeastern coastal regions of China, thick layers of marine soft soil are widely distributed, exhibiting characteristics such as high compressibility, high porosity, low strength, high sensitivity, and easy thixotropy, and these viscoelastic behaviors of foundation soil have significant implications for elastic compression bending bar, as evidenced by issues such as post-construction settlement of roadbeds and long-term operation deviation of bridge pile foundations. In this study, a mechanical model of an elastic bar embedded in an elastic and viscoelastic medium, fixed at the base and free at the top, is established based on the Winkler foundation assumption. The deflection function of a bar subjected to both axial force and locally distributed horizontal load is derived using the Rayleigh-Ritz method. Utilizing the elastic-viscoelastic correspondence principle, the viscoelastic medium surrounding the bar is modeled as an elastic medium in which the ground reaction coefficient varies within phase space formulation. This study provides a robust theoretical foundation for soft soil foundation engineering projects and fills a significant gap in the literature by offering a comprehensive framework for understanding displacement in elastic bars within viscoelastic media. Drawing upon the derivation of the deformation function for elastic rods within a viscoelastic medium, the findings of this research hold significant applicability across a range of domains. These include, but are not limited to, the expansion of roadways in regions characterized by coastal soft soil, as well as the monitoring of deformation and lifespan in bridge pile foundations.

Experimental Study on the Bond Performance between Glass-Fiber-Reinforced Polymer (GFRP) Bars and Concrete

By investigating the bond performance between glass-fiber-reinforced polymer (GFRP) bars and concrete, GFRP bars can be better applied to concrete structures as a building material. This paper considered the effects of three different GFRP bar surface treatments, three bonding lengths, corrosive solution, and immersion time on the bonding strength. The test results indicated that the bond strength decreases with the increase in the diameter and bond length. The bonding between GFRP bars and concrete can be improved by treating the surface of the bars in different ways. Compared with the control group, the bond strength of the specimens in the saline solution decreased by 1.3–21.4%, and the bond strength of the specimens in the alkaline solution decreased by 26.5–38.8%. In the corrosive environment, the bond properties are degraded. A bond strength calculation formula considering the surface treatment method of the GFRP bars was proposed. The prediction formula of the bond strength retention rate between the GFRP bar and concrete in the corrosive environment was established. The formula was validated with the available research data and the calculated values agreed well with the test values. The MBPE model and CMR model are modified to establish the bond-slip model of the GFRP bars and concrete in the corrosive environment. The model curve is close to the test curve. This paper provides a theoretical basis for future research on the bond-slip performance of GFRP bars and concrete.

INFUSION OF POLYA AND DIGITAL BAR MODEL: AN ALGEBRAIC THINKING MODULE FOR SEVENTH GRADERS

Algebraic Thinking Skills (ATS) are one of the skills that students need to master in order to solve non-routine problems. These skills are also necessary as a foundation for students preparing to enter university studies and fields of work that require logical and analytical thinking. However, Malaysian students' performance in solving algebraic problems still needs to be satisfactory, according to the TIMSS 2019 and PISA 2018 reports. Therefore, the Algebraic Thinking Skills Module (ATSM) was developed to cultivate ATS through three constructs, namely i) arithmetic generalization, ii) functions, and iii) modelling. The ATSM was developed using the heuristic method by infusing the Polya and digital bars model. The bar model illustrates a rectangle representing known and unknown quantities and the relationship between quantities. The digital bar model refers to the free application of the bar model at https://mathsbot.com/manipulatives/bar. An ATS test was developed and administered as a pre-and post-test on 120 seventh graders from rural schools in Sabah. The paired sample t-test results showed a significant difference in the mean scores between the pre-test and post-test after the intervention using the ATSM. This shows that the ATSM can improve ATS through the infusion of the Polya and digital bars model. The ATSM is able to help rural schools to shape algebraic thinkers and digitally savvy students. Keywords: algebraic thinking skills, digital bar model, non-routine problem solving, Polya

Beyond time: Enhancing corrosion resistance of geopolymer concrete and BFRP bars in seawater

To improve the durability of Basalt fiber reinforced polymer (BFRP) bars reinforced geopolymer concrete (GPC), it is important to study the time-dependent variation of the corrosion resistance ability of GPC and BFRP in a seawater environment. This paper presents an experimental investigation to study the time-dependent mechanical properties and durability of BFRP bars and geopolymer materials synthesized by granulated blast furnace slag (GGBFS), fly ash, and silica fume. The resulting GPC and Portland cement (PC) concrete were exposed to artificial seawater. The mechanical properties of GPC were evaluated by analyzing and comparing the volume expansion and strength loss rates of GPC and PC concrete in an artificial seawater environment. The corrosion resistance of geopolymer (GP) mortar and PC mortar was evaluated by studying the migration ability and pore structure in corrosive ions attack (Cl−, SO42−, Mg2+) in artificial seawater. Moreover, the time-dependent tensile strength of BFRP was comparatively investigated by immersing in different solutions (tap water, artificial seawater, and alkaline simulated seawater). In addition, the dual interface transition zones (ITZs) characteristics of BFRP reinforced GPC under artificial seawater were also investigated by SEM and BSE tests. The results showed that the volume expansion rate and strength loss rate of GPC decreased by 77.6% and 8.7%, respectively, after 360 days of seawater corrosion compared with PC concrete. This enabled the development of a time-dependent strength model of GPC in marine environments. The coefficient of ions diffusion in GP mortar is much lower than that of PC mortar, and GP mortar shows excellent resistance to ion migration. In addition, the effect of seawater corrosion on the tensile strength of BFRP bars increases with the increase of bars' diameter, and the ultimate strengths of BFRP bars with diameters of 6 mm and 8 mm were 695 MPa and 663 MPa, respectively. The tensile strength degradation model of BFRP bars in geopolymer concrete under seawater corrosion was established. After 360 days of seawater immersion, the average porosity of the ITZ between geopolymer and aggregates, and the average porosity of the ITZ between geopolymer and BFRP bars increased insignificantly compared to that of PC concrete. This research can provide a theoretical basis for the service life prediction of BFRP reinforced geopolymer concrete within marine environments.

Interlaminar Shear Property and Strength Prediction Model for Hybrid Fiber-Reinforced Polymer Bar after Exposure to Simulated Concrete Environments

The load-transfer mechanism in the fiber-reinforced polymer (FRP) bars is different from that of the conventional steel bars. The efficiency of stress transfer in FRP bars mainly depends on the mechanical properties of matrix resin, fibers, and fiber/matrix interface, which are easily degraded after long-term exposure to concrete environment. Herein, the interlaminar shear properties of a novel carbon/glass hybrid fiber-reinforced polymer (C/G-HFRP) bar were experimentally investigated by the accelerated aging tests at 60°C to study the effects of the ratio of carbon to glass fiber volume fractions, distribution configuration of carbon fiber, total fiber volume fraction, exposure environment, and exposure period. Water uptake tests, scanning electron microscopy, and Fourier transform infrared spectroscopy were employed to explore the degradation mechanisms of exposed samples. The results indicated that the interlaminar shear strength (ILSS) retention of exposed C/G-HFRP bars was higher than that of the single glass-FRP bar, which was decided by tooth force and friction. In addition, the degradation of C/G-HFRP bars was also related to water uptake rate, and then waterproof coating and fiber modification are recommended to improve the durability of C/G-HFRP bars. Finally, a model of ILSS retention was proposed for the C/G-HFRP bars after exposure to different concrete environments.

A Vehicle–Bridge Interaction Element: Implementation in ABAQUS and Verification

Vibration analysis of bridges induced by train loads is a crucial aspect of railway design, particularly considering the complexity of vehicle components such as bogie-suspension systems. Consequently, railway engineers have endeavored to improve the computational efficiency and applicability of train models using the finite-element method. This paper introduces a toolbox implemented in ABAQUS through a user-defined element (UEL) subroutine, which incorporates the vehicle–bridge interaction (VBI) element theory. This toolbox effectively handles diverse vehicle–bridge interaction systems. In the proposed theory, the wheel-track contact force is derived based on the bridge response, eliminating the need for an iterative process and significantly reducing computational workload compared to classical physics-based analysis. The presented approach is validated through a moving sprung mass model and a moving rigid bar model. Furthermore, a case study is conducted on a three-dimensional finite-element model of a high-speed railway bridge in China, based on a design sketch, to showcase the capabilities of the developed scheme. The study demonstrates the practical application of the proposed methodology in analyzing vehicle–bridge structures with high complexity.

Progressive collapse behaviour of advanced precast reinforced concrete joints with headed bars and plastic hinge relocation

This study proposed three types of precast concrete (PC) wet joints, viz., using Headed bars (Type H) to replace hooked bars, placing an Additional bottom bar layer (Type A), or implementing plastic hinge relocation method with X-bent bars (Type X) in the beam-joint region. These detailing features could compensate for negative effects caused by geometric discontinuity at the joint interface and prevent pull-out failure, as observed in conventional PC joints with hooked bars. An experimental investigation based on four interior joints showed that based on the steel content in Type H joint, by increasing respective steel contents of 7% and 8% in Type A and Type X joints, structural resistance to collapse could be enhanced by 34% and 47%, respectively. A fourth specimen of Type A joint incorporated the slab. It was found that although the slab could slightly enhance flexural resistance, it also reduced the joint rotational capacity. Subsequently, component-based joint models (CBM) with a bond-slip model of headed bars were proposed for the three types of PC joints and validated against the test results with satisfactory accuracy. Based on the validated CBMs, parametric studies were conducted for different cases, such as exterior and penultimate joints, under a penultimate column removal scenario. It was found that if the exterior column was too weak, compressive arch action and catenary action could not be effectively triggered, and column failure governed joint behaviour. Hence, to mitigate progressive collapse, the exterior columns and joints must be required to possess a sufficient level of horizontal resistance and stiffness.

SCAD model of solid finite elements: calculation of reinforced concrete waffle slabs

Introduction. Current requirements for structural engineering oblige designers to use structures capable of resisting progressive collapse. Such structures include multiribbed reinforced concrete waffle slabs. Spatial systems are multiple indeterminate, their calculation is carried out in software systems based on the finite element method. Models of ribbed structures can be developed from different types of finite elements. The forces determined by different models can vary significantly, which is confirmed by the examples available in the literature.Aim. To detect a simple and accurate finite element model for computer-aided calculating the ribbed reinforced concrete waffle slab.Materials and methods. The study was carried out by comparing the bending moments obtained analytically and in the SCAD software by the finite element method for beams in waffle slabs of 12.0 × 18.0 m in plan with caissons of 1.5 × 2.25 m. The bar model consisting of a T-beam-and-girder construction and a solid model of bulk finite elements are calculated.Results. The bending moments, calculated both analytically and using a solid model, have similar values. The maximum deviations of the computer calculation from the analytical method are from -3.2 to +2.6 %. The maximum deviations of the values of bending moments obtained when comparing the solid model with the bar model are from -9.2 to +4.0 %.Conclusion. The finite element model, which is based on solving the volumetric problem of the elastic theory, is an effective verification model for studying complex systems; however, it is time-consuming and difficult for data analysis. A solid model can be recommended for studying individual structures or their critical zones.

Establishing a novel adaptive fuzzy control algorithm for an active stabilizer bar with complex automotive dynamics model

Rollovers can cause many hazards to the passengers in the car. The main cause of this problem is the driver's sudden steering at high speed to avoid an obstacle or enter a roundabout. To limit this phenomenon, it is necessary to equip the car with an active stabilizer bar. In this article, we use a new fuzzy control method to direct an active stabilizer bar. This method is established based on five points of view regarding the stability and responsiveness of the system, so it is called the novel adaptive fuzzy algorithm (NAFC). This is a completely new point in the article compared to previous studies. A combined dynamics model that is a fusion of the seven DOFs spatial dynamics model and the three DOFs motion model. The simulation and calculation occur in the Simulink® interface, with two cases representing the steering angles J-turn and Fish-hook. The speed of the car is changed according to three specific values. According to the calculation results, the vehicle body roll angle is greatly reduced when using active stabilizer bars controlled by the novel adaptive fuzzy algorithm. Besides, the minimum dynamic force value at the rear wheel is better guaranteed. The car's roll index is also sharply reduced when applying this algorithm to the hydraulic stabilizer bar model. In addition, rollover occurs when the car steers the J-turn at v3 and the fish hook at v2 and v3 (if stabilizer bars are unavailable). Meanwhile, car’s stability is always guaranteed in the case of a car with a stabilizer bar using the NAFC algorithm. The article's achievements can be used as a basis for developing more complex control algorithms in the future.

Enhancing the lateral stability of the vehicle by using a fuzzy algorithm to control the active stabilizer bar

This article studies the instability of automobiles when steering at high speeds. In this article, the model of spatial dynamics is used to simulate vehicle oscillation. Besides, the model of nonlinear double-track dynamics is also combined to determine the effects of the wheel when steering. To limit the instability when steering, the hydraulic stabilizer bar is suggested. The performance of the system depends on the previously designed controller. The FLC algorithm with two inputs is used to control the operation of the system. The membership function and fuzzy rules are determined based on the designer’s experience. The simulation is performed by MATLAB software with three specific steering cases. In each case, the speed of the vehicle will be increased gradually. The results of the article show that the value of the roll angle is greatest in the third case, corresponding to the speed of v3 = 100 (km/h). If the vehicle does not have a stabilizer bar, the vehicle can roll over at any time. In contrast, when the active stabilizer bar was combined with the proposed FLC algorithm, the vehicle’s stability was significantly improved. The vehicle’s roll angle and the difference in vertical force at the wheels were also significantly reduced when using this algorithm for the stabilizer bar model. This result should be further verified through the experimental process.

On developing accurate prediction models for residual tensile strength of GFRP bars under alkaline-concrete environment using a combined ensemble machine learning methods

GFRP (Glass-fiber reinforced polymer) bars are recognized as a structural material enabling replace existing steel rebar. However, GFRP bars exhibit a decrease in tensile strength under severe conditions such as strong alkalinity, high salinity, and humid environment. Thus, a predictive model for such GFRP tensile strength deterioration attempts to be developed, but model accuracy still needs improvement. Therefore, this paper proposes a more enhanced ensemble machine learning model to predict the residual tensile strength of GFRP bars accurately. For this end, tensile strength retention (TSR) experiment results of GFRP bars are utilized. Critical parameters for GFRP TSR are diameter, fiber volume fraction, pH, temperature, and exposure time. Regarding the TSR prediction model of GFRP bar, single machine learning models such as multiple linear regression, nonlinear regression, support vector machine, artificial neural network, and Gaussian process regression show 0.482–0.894 for training and 0.412–0.813 for testing, based on the accuracy of coefficient of determination (R2). Individual ensemble learning machine learning models of bagging and stacking show an accuracy of about 0.897 for training and 0.816 for testing. The proposed model shows an accuracy of about 0.912 for training and 0.834 for testing, which improves about 4–22% compared to previous study model performances.

Quantifying the influence of bars on action-based dynamical modelling of disc galaxies

ABSTRACT Action-based dynamical modelling, using stars as dynamical tracers, is an excellent diagnostic to estimate the underlying axisymmetric matter distribution of the Milky Way. However, the Milky Way’s bar causes non-axisymmetric resonance features in the stellar disc. Using RoadMapping (an action-based dynamical modelling framework to estimate the gravitational potential and the stellar distribution function), we systematically quantify the robustness of action-based modelling in the presence of a bar. We construct a set of test-particle simulations of barred galaxies (with varying bar properties), and apply RoadMapping to different survey volumes (with varying azimuthal position, size) drawn from these barred models. For realistic bar parameters, the global potential parameters are still recovered to within ∼1–17 per cent. However, with increasing bar strength, the best-fitting values of the parameters progressively deviate from their true values. This happens due to a combination of radial heating, radial migration, and resonance overlap phenomena in our bar models. Furthermore, the azimuthal location and the size of the survey volumes play important roles in the successful recovery of the parameters. Survey volumes along the bar major axis produce larger (relative) errors in the best-fitting parameter values. In addition, the potential parameters are better recovered for survey volumes with larger spatial coverage. As the Sun is located just ∼28°–33° behind the bar’s major axis, an estimate for the bar-induced systematic bias – as provided by this study – is therefore crucial for future modelling attempts of the Milky Way.

Intelligent Modeling of Edge Components of Prefabricated Shear Wall Structures Based on BIM

Building Information Modeling (BIM) is a digital tool that can be used to create three-dimensional models of components. BIM technology, with its parameterized modeling scheme, can effectively address design changes. The use of BIM technology in prefabricated shear wall structures can significantly enhance component design accuracy and production efficiency. The Tekla software offers significant advantages in BIM deepening design. By utilizing the C# language, secondary development of the Tekla software, and the development of an intelligent modeling program for the edge components of prefabricated shear wall structures, the deepening design efficiency of such structures can be improved. The creation of BIM models is a crucial step in program development. Different types of reinforcements require various modeling methods, which, when combined with the design specifications of concrete structures, can be compiled to create the fine reinforcement model. This allows for the automatic creation of three-dimensional reinforcement models: “linear-shaped,” “T-shaped,” and “L-shaped” joints of the edge member. The BIM visualization characteristics can then display the three-dimensional model of the steel bar of the edge member in the cast-in-place area, deriving the engineering quantity of the steel bar for the production and construction of the prefabricated members. The modeling program’s development concept can serve as a reference for similar engineering applications, promoting the intelligent development of prefabricated building design and enhancing the efficiency of design and construction.

Application of BIM to Rebar Modeling of a Variable Section Column

A planar construction drawing is usually used to guide the construction of reinforced concrete structures in the construction industry. Due to a lack of effective technical methods, the accuracy of rebar engineering lofting is insufficient. The rejection rate of rebar is high, which results in high processing costs. Under the background of intelligent construction and BIM technology, the prefabricated factory adopts an automatic production mode to concentrate on steel bar processing, which improves production quality and processing efficiency and reduces production costs. Based on Revit secondary development, using the C# programming language, combined with the Revit API development interface, an automatic 3D modeling plugin for a reinforced concrete variable cross-section column is developed. The BIM model of steel bars is quickly generated, and the engineering quantity of steel bars is automatically calculated, which saves time for the designer to build the BIM model. It is conducive to the automatic assembly and intelligent construction of reinforced concrete engineering, which promotes the information and intelligent development of reinforced concrete structure construction.

Bond Stress Distribution and Bond–Slip Model of Deformed Steel Bars in Iron Tailing Sand Recycled Aggregate Concrete

In this study, the bond stress distribution and bond–slip model of steel bars and iron tailing sand recycled aggregate concrete (ITRAC) were investigated using central pullout tests on 33 steel bars and ITRAC bonded specimens. The results show three failure modes for the bonded specimens: splitting, pullout, and splitting–pullout. Compared with the maximum bond strength of nature sand concrete (NAC), the maximum bond strength of the iron tailing concrete and ITRAC specimens increased by 23.12% and 6.08–23.96%, respectively. After adding 1% steel fiber, the maximum and residual bond strengths of ITRAC increased by 40.82% and 129.10%, respectively, compared with those of NAC. The maximum bond strength of ITRAC decreased after the configuration of the stirrups. The bond stress distribution characteristics of the ITRAC specimens resembled those of recycled aggregate concrete (RAC). Generally, two bond stress peaks emerged, and the uniformity of the bond stress distribution improved after adding RAC to the iron tailing sand (ITS). The results of the proposed ITRAC bond–slip constitutive model agreed with the test results.