Real-time Strain Research Articles

Fiber bragg grating sensors to monitor strain response of epoxy resin during curing and cryogenic temperature

The epoxy resin is one of the critical components of large-scale superconducting magnets which find wide applications in magnetic confinement fusion, high energy accelerator and magnetic resonance imaging. In general, magnetic confinement fusion, high energy accelerator and magnetic resonance will be used at cryogenic temperatures. An approach with respect to real-time monitor of epoxy curing and cryogenic process is practically significant for magnetic reliability, maintainability as well as future mass production. Fiber Bragg Grating (FBG) sensors are excellent candidates of this measurement for their anti-electromagnetic interference characteristics and high sensitivity. The aim of this work is to use the embedded Fiber Bragg Gratings (FBG) to obtain real-time strain response of curing epoxy, and the strain change of the epoxy at cryogenic temperature from 4.2K to 300K. An FBG pre-tensioning device was designed to keep the FBG embedded in the epoxy in a stretched state during the epoxy curing process. Moreover, strain gauge sensors were also embedded to monitor the curing process at the same time. There are subtle differences in strain values obtained by the two sensors, which illustrate higher sensitivity of FBGs. This work verifies the reliability of FBG monitoring the strain response of epoxy during curing process as well as the cryogenic service.

Dynamic strain measurement in Brillouin optical correlation-domain sensing facilitated by dimensionality reduction and support vector machine.

Brillouin optical correlation-domain sensing enables high-speed Brillouin gain spectrum (BGS) measurement at random positions along the optical fiber. To extract the Brillouin frequency shift (BFS) that reflects the real-time strain information, machine learning methods of principal components analysis (PCA) and support vector machine (SVM) are used in the signal processing for the BGSs. The performances of dimensionality reduction by PCA and SVM based on classification and regression are analyzed and compared. The experiment demonstrates an 8 kHz BGS acquisition repetition rate and an average BFS extraction time of 0.0104 ms, which is 27.3 times faster than the conventional method with no PCA. The proposed methods realize a real-time dynamic strain measurement at the frequency of 40 Hz.

Ultra-high temperature video extensometer: System development and experimental validation.

The video extensometer has been widely advocated for tensile/compressive strain measurement in high-temperature material testing due to its advantages of non-contact measurement, wider measuring range, and larger applicable temperature over traditional clip-on mechanical extensometers. However, existing video extensometers, despite the adoption of active imaging devices, cannot adapt to the rapidly changing thermal radiation from the heated sample and surrounding heating elements during the high-temperature tests. This is because due to the significantly intensified thermal radiation, the decorrelated images degrade the measuring accuracy or even destroy the analysis. To address this problem, we developed an ultra-high temperature video extensometer that can automatically adjust the camera exposure time for reliable thermal strain measurement. Based on the pre-established image quality evaluation criteria, the camera will choose an appropriate exposure time according to the detected thermal radiation within the region of interest, thus ensuring high-quality images for real-time strain measurement. Static tests of tungsten-molybdenum alloy samples at different temperatures were performed to evaluate the noise level of the established ultra-high temperature video extensometer. The effectiveness and accuracy of the developed ultra-high temperature video extensometer were validated through the tensile tests of tungsten-copper, tungsten-potassium, and tungsten-molybdenum alloy samples at high temperatures up to 2000 °C.

AI-based modeling and data-driven identification of moving load on continuous beams

Traffic load identification for bridges is of great significance for overloaded vehicle control as well as the structural management and maintenance in bridge engineering. Unlike the conventional load identification methods that always encounter problems of ill-condition and difficulties in identifying multi parameters simultaneously when solving the motion equations inversely, a novel strategy is proposed based on smart sensing combing intelligent algorithm for real-time traffic load monitoring. An array of lead zirconium titanate sensors is applied to capture the dynamic responses of a beam bridge, while the Long Short-Term Memory (LSTM) neural network is employed to establish the mapping relations between the dynamic responses of the bridge and the traffic load through data mining. The results reveal that, with the real-time strain responses fed into the LSTM network, the speed and magnitude of the moving load may be identified simultaneously with high accuracy when compared to the practically applied load. The current method may facilitate highly efficient identification of the time-varying characteristics of moving loads and may provide a useful tool for long-term traffic load monitoring and traffic control for in-service bridges.

Study on the effectiveness of fibre reinforcement on the engineering performance of foamed concrete

Mechanical properties, workability and pore structures of foamed concrete (FC) reinforced with different fibres were investigated. In order to characterise the cementitious matrix with entrained bubbles and fibres, X-ray computed tomography (X-CT) technology and Digital image correlation (DIC) technique were employed to analyse the pore structure and the real-time strain field distributions under applied loads, respectively. The results demonstrated that the inherent properties of fibres, including density, modulus and wettability, and bond performance between the cement matrix and fibres are two main factors in determining the mechanical properties of the fibre reinforced FC. Meanwhile, the fibres also had an influence on the workability and rheological properties of fresh FC slurry through changing the bubble numbers and distributions in the slurry. According to the strain analysis during the bending tests using the DIC technique, it was found that carbon fibre and polyacrylonitrile fibre were conducive to distributing the strain field in the FC in a homogeneous fashion and delayed crack widening after the peak loads effectively.

Laser Direct-Write Sensors on Carbon-Fiber-Reinforced Poly-Ether-Ether-Ketone for Smart Orthopedic Implants.

Mechanically close‐to‐bone carbon‐fiber‐reinforced poly‐ether–ether–ketone (CFR‐PEEK)‐based orthopedic implants are rising to compete with metal implants, due to their X‐ray transparency, superior biocompatibility, and body‐environment stability. While real‐time strain assessment of implants is crucial for the postsurgery study of fracture union and failure of prostheses, integrating precise and durable sensors on orthopedic implants remains a great challenge. Herein, a laser direct‐write technique is presented to pattern conductive features (minimum sheet resistance <1.7 Ω sq–1) on CRF‐PEEK‐based parts, which can act as strain sensors. The as‐fabricated sensors exhibit excellent linearity (R 2 = 0.997) over the working range (0–2.5% strain). While rigid silicon‐ or metal‐based sensor chips have to be packaged onto flat surfaces, all‐carbon‐based sensors can be written on the complex curved surfaces of CFR‐PEEK joints using a portable laser mounted on a six‐axis robotic manipulator. A wireless transmission prototype is also demonstrated using a Bluetooth module. Such results will allow a wider space to design sensors (and arrays) for detailed loading progressing monitoring and personalized diagnostic applications.

REAL-TIME strain elastography: Applications in musculoskeletal system

BackgroundStrain or compression sonoelastography (CE) provides a colour-coded elastogram representing tissue elasticity by measuring tissue deformability after repeated probe compression. Elastographic ultrasound (EUS) is a valuable tool for screening diagnosis and follow-up of inflammatory, degenerative, benign and malignant neoplastic pathologies of skin, subcutaneous tissue, muscles, tendons, ligaments, fascia and nerves; help in targeted biopsy; monitor healing tendons after surgery or nerve stiffness changes during physiotherapy. ObjectivesTo assess stiffness of normal tendons, muscles and nerve. To diagnose cellulitis, fasciitis, abscess, tendinopathy, myositis, muscle/tendon rupture/contusion and differentiate between benign and malignant soft tissue tumours. To derive elastic score (ES) and strain ratio (SR) in cases and controls. To correlate B-mode findings with CE. Materials and methodsA prospective study on 50 healthy subjects between 25 and 30 years and 50 cases of diffuse and focal musculoskeletal pathologies was done using B-mode and CE over 2 years. Statistical analysis of distribution, mean, associations, sensitivity, specificity, area under Receiver Operating Characteristic curve (AUROC) for B-mode, ES, SR combined B-mode/CE and their comparison was done. ResultsSignificant association was noted between SR in muscles and tendons with sex. Significant correlation was noted between ES/SR with B-mode. CE and B-mode had 100% and 52.4% sensitivity respectively for diagnosing diffuse pathologies. For differentiating benign and malignant masses sensitivity, specificity, and diagnostic accuracy of B-mode was 71.43%, 86.36% and 82.76%; of SR was 71.43%, 90.91% and 86.21%; of Combined B-mode with CE was 100%, 90.91% and 93.1% respectively. Elastographic pattern had highest diagnostic accuracy and largest AUROC. ConclusionCE as a screening test had higher diagnostic accuracy, supporting need for standardizing it for clinical use in MSK. EUS being a widely available, fast and affordable modality, can aid follow up of chronic MSK pathologies, response to medication, physiotherapy and surgery and mitigate the need for MRI.

A Unified Full-Field Deformation Measurement Method for Beam-Like Structure

Full-field displacement reconstruction, which uses a few strain sensors for obtaining real-time surface strain as the input data of the monitoring system, is a crucial technology to actuate and control smart structures. In the previous reconstruction algorithm, the displacement vectors consistent with some particular kinematic assumptions of the deformation theory should be determined in advance. However, obtaining the displacement vectors of complex structures accurately and quickly is difficult in engineering. Therefore, the attentions are mainly on seeking a unified method to avoid the reconstruction errors caused by structural misidentification. For this purpose, some particular generalized quantities are adopted to replace the traditional displacement functions, and the unified displacement field of beam-like structures is proposed based on the homogenized theory. Meanwhile, the reconstruction function is established based on the classic inverse finite-element method (iFEM). Next, the transformation relationships are determined between the generalized numerical strains and the measured strains using a tailored strain measurement scheme. Finally, several beam-like structures with different slenderness ratios are used as the test examples to verify the reliability and effectiveness of the presented full-field displacement monitoring method. The simulation and experimental results demonstrate the superior precision and stable reliability of the presented measurement method for performing shape sensing of beam-like structures.

Correlation of Amount of Cigarette Smoking with Thickness and Elasticity of Distal Femoral Cartilages using Sono-Elastography Techniques of Ultrasound, a Cross-Sectional Study.

Introduction: Cigarette smoking is a well-known etiology for chronic musculoskeletal system disorders, like osteoarthritis, affecting the distal femoral cartilages. However, recent studies show protective effects of smoking against osteoarthritis. Ultrasound is an easily accessible and reliable imaging tool for the evaluation of the cartilages, measurement of their thickness, and tissue stiffness. This study seeks to objectively show the effects of smoking by affecting their knee joints’ cartilage and clarify whether it has a chondroprotective effect, or support the usual evidence that smoking is harmful at any cost. Methods: This prospective cross-sectional study compares the thickness and elasticity of distal femoral cartilage in heavy, ordinary smokers and non-smokers using B-mode scanning and real-time strain elastographic technique of ultrasound respectively. Results: Among 377 individuals with a mean age of 27.66 years, male predominance (70 %) and mean Body Mass Index (BMI) of 24.55, a higher proportion (50 %) of volunteers were ordinary smokers (pack years &lt;20). Elasticity strain ratios were found to be significantly lower in heavy smokers in both sides’ distal femoral cartilages except in right lateral cartilage (p = &lt;0.001) using Fisher’s exact test. Significantly lower thickness was noted in both cartilages of the right side (p &lt;0.001) and left lateral cartilage (p = 0.001) among heavy smokers. After adjusting for the effects of age, sex, BMI, and occupation using one-way ANOVA, similar results were obtained. Conclusions: Heavy cigarette smoking causes degradation of distal femoral cartilages by decreasing their thickness and elasticity.

Differentiation of benign and malignant superficial soft tissue lesions using real-time strain elastography

To evaluate benign and malignant cutaneous-subcutaneous lesions using real-time strain elastography (RTSE) and to compare the findings with histopathologic results. Over a period of 10 months, 72 patients (38 with benign and 34 with malignant cutaneous and subcutaneous lesions) were prospectively included in this study. Elasticity patterns and strain ratios were examined for each lesion. Lesions were evaluated in 4 groups as yellow-red (soft; pattern-1), green-yellow (moderate; pattern-2), blue-green (hard; pattern-3) and blue (hardest; pattern-4). The stiffness of the lesions was displayed with strain ratios by comparing of a nearby reference tissue. The recorded images were compared with histopathologic findings. On sonoelastograms, considering patterns 1-2 as benign and patterns 3-4 as malignant, the sensitivity, specificity, and positive and negative predictive values for the differentiation of malignant from benign lesions were 100%, 68.5%, 74%, and 100%, respectively. Considering a cut-off value of the strain ratio as > 3.05, the sensitivity, specificity, and positive and negative predictive values were 91%, 89%, 88%, and 92%, respectively. The area under the curve (AUC: 0.972) showed the excellent ability of strain elastography to differentiate benign and malignant lesions. RTSE is an important imaging tool to differentiate benign and malignant superficial soft tissue lesions. Our results suggest that RTSE can be used to predict malignancy since malignant lesions are more confidentially diagnosed than benign superficial soft tissue lesions on elastograms.

Real-Time Strain and Elasticity Imaging in Phase-Sensitive Optical Coherence Elastography Using a Computationally Efficient Realization of the Vector Method

We present a real-time realization of OCT-based elastographic mapping local strains and distribution of the Young’s modulus in biological tissues, which is in high demand for biomedical usage. The described variant exploits the principle of Compression Optical Coherence Elastography (C-OCE) and uses processing of phase-sensitive OCT signals. The strain is estimated by finding local axial gradients of interframe phase variations. Instead of the popular least-squares method for finding these gradients, we use the vector approach, one of its advantages being increased computational efficiency. Here, we present a modified, especially fast variant of this approach. In contrast to conventional correlation-based methods and previously used phase-resolved methods, the described method does not use any search operations or local calculations over a sliding window. Rather, it obtains local strain maps (and then elasticity maps) using several transformations represented as matrix operations applied to entire complex-valued OCT scans. We first elucidate the difference of the proposed method from the previously used correlational and phase-resolved methods and then describe the proposed method realization in a medical OCT device, in which for real-time processing, a “typical” central processor (e.g., Intel Core i7-8850H) is sufficient. Representative examples of on-flight obtained elastographic images are given. These results open prospects for broad use of affordable OCT devices for high-resolution elastographic vitalization in numerous biomedical applications, including the use in clinic.

Tumor microenvironment-responsive touch sensor-based pH-triggered controllable conductive hydrogel

A tumor microenvironment-responsive wireless strain-pressure hydrogel sensor based on pH-induced controllable nanoparticles was designed for cancer detection in vitro–in vivo model, with excellent ability to distinguish between cancer and normal cells. The pH-responsive nanoparticles (CD-PNB), comprising diol–diol crosslinked semiconducting carbon dots (CDs) and non-conductive polymer (PNB), are sensitive to acidic tumor microenvironments and play crucial role in demonstrating tumor-selective strain-pressure responses. Upon application of strain and pressure, CD-PNB@PVA hydrogel produced distinct electronic signals in the presence of cancer cells (HeLa, PC-3), exhibiting higher strain–pressure sensitivity compared to the normal cells (MDCK, CHO-K1). The strain and pressure gage factors for cancer-cell-treated CD-PNB@PVA hydrogel were found to be 0.7439 and 5.3052 kPa−1, which were higher than normal-cell-treated CD-PNB@PVA hydrogel (0.5009 and 4.2720 kPa−1). CD-PNB@PVA hydrogel demonstrated excellent response in tumor-bearing mice based on in situ and ex situ measurements, with no inflammation during hydrogel implantation. Moreover, wireless sensing system was used along with CD-PNB@PVA hydrogel to simplify monitoring process and obtain real-time conductivity and strain–pressure profiles on smartphone. Thus, this approach constructs a tumor microenvironment-responsive strain–pressure hydrogel sensor and presents potential for sensitive and selective tumor detection in point-of-care diagnostic applications.

Tension-Compression Fatigue Induced Stress Concentrations in Woven Composite Laminate

Tension-compression (T-C) fatigue response is one of the important design criteria for carbon-fibre-reinforced polymer (CFRP) material, as well as stress concentration. Hence, the objective of the current study is to investigate and quantify the stress concentration in CFRP dog-bone specimens due to T-C quasi-static and fatigue loadings (with anti-buckling fixtures). Dog-bone specimens with a [(0/90),(45/−45)4]s layup were fabricated using woven CFRP prepregs and their low-cycle fatigue behaviour was studied at two stress ratios (−0.1 &amp; −0.5) and two frequencies (3 Hz &amp; 5 Hz). During testing, strain gauges were mounted at the centre and edge regions of the dog-bone specimens to obtain accurate, real-time strain measurements. The corresponding stresses were calculated using Young’s moduli. The stress concentration at the specimen edges, due to quasi-static tension, was significant compared to quasi-static compression loads. Furthermore, the stress concentration increased with the quasi-static loading within the elastic limit. Similarly, the stress concentration at the specimen edges, due to tensile fatigue loads, was more significant and consistent than due to compressive fatigue loads. Finally, the effects of the stress ratio and loading frequency on the stress concentration were noted to be negligible.

Analytical elastoplastic model for stress and strain of the equivalent representative volume element and material testing application

For unidirectional loaded specimens consisting of isotropic-homogeneous ductile materials, an analytical elastoplastic model for the equivalent stress and strain of the representative volume element at the median point were derived based on energy density equivalence and dimensional analysis. Then, a data processing method for various specimen types was proposed to obtain the equivalent stress–strain in real time without presetting the constitutive parameters. Finite element analyses of six specimen types and experiments with four selected specimen types were conducted to verify the method. The results show that the stress–strain curves obtained using this method were consistent with the preset stress–strain curves in the finite element analysis and with the standard tensile results. Using the proposed model and relevant data processing method to obtain the stress–strain curves is effective and, with the theoretical basis, could promote the application of non-tradition and small specimens for obtaining the material mechanical properties.

Real-time strain monitoring of reinforced concrete under the attacks of sulphate and chloride ions based on XCT and DIC methods

In this work, the influences of different sulphate and chloride laden environment on the corrosion of reinforced concrete have been examined in real time by the digital image correlation (DIC) technology combined with a traditional strain measurement, and the applicability of DIC technology for monitoring the entire life cycle of reinforced concrete is verified. The main testing parameters include: (1) electrical current between steel bar and stainless steel sheet are measured by ampere meter, (2) expansion strain values are obtained by the traditional strain measurement, (3) micro-strain fields are obtained by the DIC technology. According to the above parameters, the influence of chloride and sulphate ions on the corrosion process of concrete reinforcement can be compared and analysed. The obtained results reveal that sulphate ions inhibit the corrosion of steel bars and suppress the corrosion effect produced by chloride ions. In addition, a model for predicting the corrosion-induced expansion stress at the steel–concrete interface is established, and its time variation is accurately quantified. The critical corrosion-induced expansion stress generated in reinforced concrete under the action of a single chloride salt solution is 2.25 MPa, and the corresponding initial cracking time is equal to 100 h. Meanwhile, the corrosion-induced expansion stress of the reinforced concrete specimen exposed to a composite solution of chloride and sulphate ions is 2.0 MPa, and its initial cracking time equals 150 h.

Grain-size effect on dynamic behavior of sandstone based on high-speed 3D-DIC technique

The grain size effect on the dynamic behavior of sandstone was investigated through the compression tests on coarse-grained (CG), medium-grained (MG) and fine-grained (FG) sandstones by split Hopkinson pressure bar (SHPB) tests under the strain rates of 69–83 s–1 based on the thin section and electron scanning microscopic (SEM) images analysis, the CG, MG and FG sandstone were mainly composed by quartz with the average grain size of 200–500, 90–500 and 55–120 µm, respectively. With the increasing grain size, the percentage of clay mineral was decreased correspondingly from 8% to 1%. During the dynamic compression, two high-speed cameras were applied to capture the deformation of sandstone at frame rate of 2×105 s–1 and resolution of 256×256. The real-time strain fields of rock were obtained by high-speed three-dimensional digital image correlation (3D-DIC) technique, the dynamic deformative properties, particularly the lateral strain of the specimen, were extracted by averaging the lateral strain field by pixels. The fracturing behavior of three sandstones was analyzed through the strain localization evolution within the strain fields. Results show that the critical strain rate for reversible release of elastic strain energy increases with the decreasing grain size. The dynamic strength ascends along with the reduction of grain size, while the strain rate sensitivity to the dynamic strength has an opposite trend. Compared to the quasi-static case, the dynamic elastic modulus increases by 2–3 times for MG and FG sandstone, particularly 5 times for CG sandstone. The Poisson’s ratio under dynamic loading in FG sandstone is grown by 25%, but drops at 70% of the static one in MG sandstone. The crack primarily generates inside the specimen and propagates to the surface of the specimen afterwards. The crack development is advanced under dynamic loadings, where the normalized stress threshold for crack initiation in FG sandstone is only 10%. Based on the microscopic analysis, mineral structure and clay percentage dominate the dynamic property and fracturing behavior of sandstone, respectively.

A micro-vibration apparatus for dynamic mechanical analysis of ultrathin polymer films.

We present the designand validation of an apparatus, which is developed based on micro-vibration in cyclic bulge and contraction, to determine dynamic mechanical properties of ultrathin polymer films. By controlling air pressure acting on a polymer membrane, the apparatus exerts simple harmonic or other type periodic stresses on the film, and the resultant real-time deformation of the freely standing film is recorded by using a high-speed CCD camera. From the image frame sequences and the gas pressure data, the real-time stress and strain of the polymer film are attained. Consequently, the dynamic mechanical properties, including biaxial storage and loss moduli, and loss factor can be determined for polymer films with thickness down to 20nm. This apparatus could also be used to determine other mechanical properties such as fatigue and yield for nanoconfined films of soft matter.

A Compensation Method for Active Phased Array Antennas: Using a strain-electromagnetic coupling model

Physical deformation due to service loads seriously degrades the electromagnetic performance of active phased array antennas. However, traditional displacement-based compensation methods are moderately difficult to use because displacement measurements generally require stable references, which are hard to realize for antennas in service. For deformed antennas, strain information is directly related to their displacement, and strain sensors can overcome carrier platform constraints to measure real-time strain without affecting the antenna radiation-field distribution. We thus present a compensation method based on strain information for in-service antennas. First, the minimum number of strain sensors is determined as the main modal-order-based modal effective mass fraction. According to the modal method and analysis of spatial phase-distribution errors related to strain, a coupled strain-electromagnetic model is established to evaluate antenna performance from the measured strain. The corresponding excitation phase from the measured strain is adjusted to compensate antenna performance. Finally, the method is experimentally validated using an X-band active phased array antenna under the influence of typical deformation conditions for both boresight and scanned beams. The results demonstrate that the presented method can effectively compensate for the performance of service antennas directly from the measured strain information.

A Simple Reverse Transcriptase PCR Melting-Temperature Assay To Rapidly Screen for Widely Circulating SARS-CoV-2 Variants.

ABSTRACTThe increased transmission of SARS-CoV-2 variants of concern (VOC), which originated in the United Kingdom (B.1.1.7/alpha), South Africa (B1.351/beta), Brazil (P.1/gamma), the United States (B.1.427/429 or epsilon), and India (B.1.617.2/delta), requires a vigorous public health response, including real-time strain surveillance on a global scale. Although genome sequencing is the gold standard for identifying these VOCs, it is time-consuming and expensive. Here, we describe a simple, rapid, and high-throughput reverse transcriptase PCR (RT-PCR) melting-temperature (Tm) screening assay that identifies the first three major VOCs. RT-PCR primers and four sloppy molecular beacon (SMB) probes were designed to amplify and detect the SARS-CoV-2 N501Y (A23063T) and E484K (G23012A) mutations and their corresponding wild-type sequences. After RT-PCR, the VOCs were identified by a characteristic Tm of each SMB. Assay optimization and testing was performed with RNA from SARS-CoV-2 USA WA1/2020 (wild type [WT]), B.1.1.7, and B.1.351 variant strains. The assay was then validated using clinical samples. The limit of detection for both the WT and variants was 4 and 10 genomic copies/reaction for the 501- and 484-codon assays, respectively. The assay was 100% sensitive and 100% specific for identifying the N501Y and E484K mutations in cultured virus and in clinical samples, as confirmed by Sanger sequencing. We have developed an RT-PCR melt screening test for the major VOCs that can be used to rapidly screen large numbers of patient samples, providing an early warning for the emergence of these variants and a simple way to track their spread.

Study on The Technical Plan of Continuous Beam Rotation Construction Monitoring and Early Warning

The rotating construction of the bridge is the better choice, the continuous beam rotation intelligent monitoring system was built by the Academy of Railway Sciences and was developed and applied based on the “Smart Construction Site” project of the Huzhou-Hangzhou Railway. Firstly, this article introduces the system. The system is based on Beidou’s high-precision satellite positioning solution system to calculate the attitude of the bridge during the construction of the rotating body. The key stress level and change of the bridge can be obtained through the stress sensor,which can obtain the response trend of the pontic structure, and effectively control the stress damage and dangerous points in the first time. Secondly, it continuously moitors the temperature and humidity of the rotating bridge, wind speed, bridge pier strain, inclination angle, and rotation angle in real time during the entire course of the bridge rotation to ensure the safety of construction. Thirdly, points out the location of the sensor buried in the foundation pit during the bridge construction process. Finally, the principle and composition of the bridge health warning technology scheme based on BIM technology are introduced, and its significance and advantages are summarized. Provides solutions and experience for the long-term monitoring of bridges in rotating construction.