Yi Bao

Stevens Institute of Technology · Department of Civil, Environmental & Ocean Engineering

Reconfigurable modular structures are able to be assembled using prefabricated modules and reconfigured to promote automated construction and to improve sustainability and resilience of infrastructure, while the computer-aided design and modeling of the modules are unclear. This study develops a many-objective optimization approach to design the mo...

This paper presents an intelligent photo interpretation approach to automatically monitor and characterize dense interconnected microcracks in strain-hardening cementitious composite (SHCC) featuring unique crack patterns in terms of crack number and crack width. The presented approach employs a stereo vision system that integrates binocular and mo...

This paper presents an AI-guided approach to automatically discover low-carbon cost-effective ultra-high performance concrete (UHPC). The presented approach automates data augmentation, machine learning model generation, and mixture selection by integrating advanced techniques of generative modeling, automated machine learning, and many-objective o...

Distributed fiber optic sensors with protective packages have shown unique capabilities in measuring strain and crack distributions for structural health monitoring. However, the mechanics at the fiber-package interface remain unclear when debonding occurs. This paper investigates the interfacial mechanics for distributed fiber optic sensors underg...

The fatigue degradation of stud connectors is generally neglected in the fatigue analysis of steel-UHPC composite decks, which may lead to inaccurate results. This paper studies the effects of stud degradation and stud arrangement on the fatigue behavior of steel-UHPC composite decks via finite element analysis. A numerical method for the fatigue a...

Microstructures of calcium silicate hydrates (C–S–H) are relevant to the mechanical properties and durability of cement-based materials. Random growth of the microstructures of C–S–H largely compromises the mechanical properties and durability. This paper proposes to utilize cellulose nanocrystals (CNCs) to modify the microstructures of C–S–H. This...

Understanding the distribution of wind field parameters over various terrains is important for kinds of applications including condition monitoring of high-speed railways and pollutant dispersion modeling. Based on Empirical Bernstein Copula (EBC), a nonparametric joint distribution model of wind speed and direction adaptable for complex wind field...

Distributed fiber optic sensors (DFOSs) offer unique capabilities for crack monitoring via measuring strain distributions. However, manually interpreting strain distributions is labor-intensive and time-consuming. To address this challenge, this paper presents a deep learning approach for real-time automatic interpretation of strain distributions,...

Fatigue cracks in rib-to-deck joints of orthotropic steel decks (OSDs) endanger the safety of bridges and are difficult to detect. This paper proposes to monitor fatigue cracks using ultrasonic Lamb waves. An OSD specimen instrumented with ultrasonic sensors was fabricated and tested to crack under fatigue loads. Ultrasonic Lamb waves were measured...

The mixing of ultra-high-performance concrete (UHPC) featuring low water-to-binder ratios involves different evolution of microstructures and mixing torques from conventional concrete. This paper investigates the mixing kinetics of UHPC in the mixing process, presents a mixing kinetics model to predict the mixing torque at an arbitrary time instant...

Distance measurement is significant for ensuring the safety and serviceability of engineering structures. Recently, ultra-wideband (UWB) sensors have offered an alternative real-time remote sensing solution to measure distances. UWB sensors exhibit small size, low cost, low energy consumption, and high robustness to weather conditions, but their ra...

In this study, an autonomous computer vision-based method is presented to quantitatively detect loose bolts. The method integrates keypoint detection via YOLOv5 and PIPNet, distortion correction via perspective transformation, and rotation angles quantification via geometric imaging. Distortion correction is incorporated to address skewed angles an...

Distributed fiber optic sensors have exhibited superior capabilities in monitoring cracks in engineering structures through measuring detailed strain distributions. However, manually interpreting the measurements from long distributed sensors deployed in large-scale structures is time-consuming, labor-intensive, and subject to human errors. This pa...

This study presents an experimental investigation on the combined effect of mechanical loads and corrosion using the designed polytetrafluoroethylene tube-packaged fiber Bragg grating (FBG) sensors, as to implement long-gauge FBG (LFBG) sensors in corrosion detection practices for structural health monitoring. A simplified LFBG-based sensing model...

Biochar has shown great promise in producing low-cost low-carbon concrete for civil infrastructure applications. However, there is limited research comparing the use of pristine and contaminated biochar in concrete. This paper presents comprehensive laboratory experiments and three-dimensional nonlinear finite element analysis on the mechanical, ec...

Engineered cementitious composite (ECC), also known as strain-hardening cementitious composite, exhibits high ductility and toughness. The high ductility and toughness of ECC are associated with finely-tuned matrix cracking, fiber rupture, and fiber-matrix debonding. This study investigates the fracture process of ECC through time-frequency analysi...

Identification of exfoliated graphene flakes and classification of the thickness are important in the nanoman-ufacturing of advanced materials and devices. This paper presents a deep learning method to automatically identify and classify exfoliated graphene flakes on Si/SiO 2 substrates from optical microscope images. The presented framework uses a...

Existing machine learning-based approaches to investigate and design concrete mainly use the mixture design variables to predict concrete properties and do not consider the physicochemical properties of ingredients such as the particle size distribution and chemical composition of various binders and aggregates. This paper presents an approach to d...

Engineered Cementitious Composite (ECC) exhibits superior mechanical properties such as high tensile strength, ductility, and toughness, which enable using thinner sections in steel-ECC composite structures. Existing design equations for the shear capacity of stud connectors were derived by regression analysis of test data from push-out specimens u...

Ultra-high-performance concrete (UHPC) has been used to enhance the mechanical behavior of orthotropic steel bridge decks through steel-UHPC composite actions. This research develops a method to evaluate the flexural behavior of steel-UHPC composite sections via experimental and analytical investigations. Four composite deck specimens were fabricat...

Externally bonding fiber reinforced polymer (FRP) to concrete structures is an effective way to enhance the mechanical performance of concrete structures. Many equations have been proposed to predict the interfacial bond strength for FRP-concrete structures but have limited accuracy due to the complexity of the bond behavior. This study proposes to...

High-performance fiber-reinforced cementitious composites (HPFRCC) have shown benefits in improving infrastructure resilience but often compromises sustainability due to the higher upfront cost and carbon footprint compared with conventional concrete. This paper presents a framework to optimize HPFRCC for improving bridge resilience and sustainabil...

Featuring high compressive and tensile strengths, ultra-high performance concrete (UHPC) is an efficient and durable alternative for conventional concrete in steel–concrete composite sections. However, few experimental studies to date have involved large diameter (≥ 25 mm) headed studs, UHPC with compressive strengths larger than 130 MPa, and relat...

Fiber Bragg grating (FBG) sensors have been applied to assess strains, stresses, loads, corrosion, and temperature for structural health monitoring (SHM) of steel infrastructure, such as buildings, bridges, and pipelines. Since a single FBG sensor measures a particular parameter at a local spot, it is challenging to detect different types of anomal...

This paper proposes to detect buckling and reconstruct three-dimensional deformations using distributed fiber optic sensors. The distributed sensors measured strain distributions with sub-millimeter resolutions based on optical frequency domain reflectometry in real time. Buckling was detected from high-resolution strain distributions measured from...

Arsenate (As(V)) in municipal wastewater leads to a public health problem due to its contamination of natural water sources. Here, we proposed to use sewer pipe made of TiO2-doped cementitious composite (TCC) for As(V) removal from municipal wastewater. The optimum composition of TCC, the performance for As(V) removal in the simulated sewer system,...

Ultra-high performance concrete (UHPC) has been used to enhance the fatigue resistance of orthotropic steel decks, but the enhancement effect is compromised by UHPC cracks in negative moment regions. This research investigates the flexural cracking behavior of reinforced UHPC (R-UHPC) overlay in composite bridge deck under static and fatigue loads....

Pipelines carrying energy products play vital roles in economic wealth and public safety, but incidents continue occurring. Condition assessment of pipelines is essential to identify anomalies timely. Advanced sensing technologies obtain informative data for condition assessment, while data analysis by human has limited efficiency, accuracy, and re...

The interfacial behaviors play significant roles in various composite materials and structures. This paper presents a logic-guided neural network to seamlessly integrate data-driven methods and scientific knowledge in predicting interfacial properties of steel-concrete composites. The investigated properties include the bond strength, interface sli...

Strain transfer phenomenon in distributed fiber optic sensors (DFOS) has shown significant effects on sensor survival and measurement of strain distributions as well as detection and quantification of cracks in health monitoring and condition assessment of civil infrastructure. This review aims to establish a holistic understanding on the strain tr...

Adding a thin layer of ultra-high performance concrete (UHPC) onto the steel deck plate is an effective approach to improve the fatigue performance of orthotropic steel decks (OSDs) through increasing structural stiffness and load-carrying capacity, but a wide industrial acceptance of the approach is hindered by heat curing of UHPC. In this study,...

Curved pedestrian bridges are important urban infrastructure with the desired adaptability to the landscape constraints and with aesthetic benefits. Pedestrian bridges feature thin cross-sections, which provide sufficient load capacities but lead to low natural frequencies that make the bridges susceptible to vibration under pedestrian excitation....

This study proposes a method to repair fire-damaged concrete beams using strain-hardening cementitious composite (SHCC) and investigates their flexural behavior through full-scale tests. Eleven beams with different reinforcement ratios were fabricated. Eight beams were damaged in fire, and six of them were repaired using SHCC or basalt-fiber-reinfo...

This research investigates the flexural behavior of steel-concrete composite floor slabs with distributed fiber optic sensors based on pulse pre-pump Brillouin optical time domain analysis. The distributed sensors were embedded in trapezoidal concrete slabs and provided in-situ real-time monitoring of initiation and evolution of cracks in the profi...

Offshore wind turbines are subjected to highly-varying dynamic loadings and accelerated material degradation, resulting in the need for structural health monitoring, which increases the operation and maintenance cost and ultimately the levelized cost of electricity. Recent advances in robotics and intelligent algorithms offer new opportunities for...

Identification of the mechanically exfoliated graphene flakes and classification of the thickness is important in the nanomanufacturing of next-generation materials and devices that overcome the bottleneck of Moore's Law. Currently, identification and classification of exfoliated graphene flakes are conducted by human via inspecting the optical mic...

Strains measured by distributed fiber optic sensors with protective coatings can be different from the real strains in host matrix due to strain transfer effect. This study presents a novel inverse method to determine the real strain distributions in host matrix using strain distributions measured from distributed fiber optic sensors. Two different...

Ultra-high-performance concrete (UHPC) emerges as an advanced material that is promising to improve the fatigue performance of bridge decks. This study evaluates the fatigue performance of steel-UHPC composite deck in the Junshan Yangtze River Bridge, which is a long-span cable-stayed bridge, under in-service traffic loads. The bridge was instrumen...

Many riveted steel bridges were constructed worldwide between 1850 and 1950. A number of them are still in operation, and their fatigue damage is a major burden in maintenance. This paper presents a unified structural stress approach to evaluate the fatigue resistance of riveted joints for steel bridges. The presented approach was utilized to estab...

This study investigates the dynamic responses of a long-span cable-stayed railway bridge with steel–concrete hybrid girders in different train load scenarios. The investigated scenarios included driving and braking of running trains. The bridge was instrumented with different types of sensors to measure strains, displacements, and accelerations dur...

Plastic viscosity is a key property of ultra-high-performance concrete (UHPC) and must be controlled during the mixing to achieve desired fresh and hardened properties. This paper presents a video recognition technology for real-time assessment of plastic viscosity using a video captured by a camera during the mixing of UHPC. A long-term recurrent...

This paper presents feasibility and benefits of utilizing off-specification fly ash (OSFA), which would have otherwise been landfilled, in preparing ultra-high-performance concrete (UHPC). Effects of mixture design variables, including OSFA content, water-to-binder ratio, and slag content, on compressive and flexural properties of UHPC were tested....

Frost heaving is one of the major diseases of post-tensioned prestressed concrete structures in cold regions. This study investigates the effects and underlying mechanisms of frost heaving damages on the mechanical behaviors of full-scale post-tensioned prestressed concrete girders of a highway bridge. Forensic investigations were performed for thr...

Machine learning methods are promising to predict key properties of concrete and expedite design of advanced concrete, but the existing methods have limitations in accuracy and generalization performance, because limited dataset size and anomalous data are used to train predictive models. This study presents an auto-tune learning framework for pred...

This study develops a framework for property prediction and multi-objective optimization of strain-hardening cementitious composites (SHCC) based on automated machine learning. Three machine learning models are developed to predict the compressive strength, tensile strength, and ductility of SHCC. A tree-based pipeline optimization method is enhanc...

This paper presents an experimental study on the punching shear behavior of concrete flat slabs partially reinforced with ultra-high-performance concrete (UHPC). The effects of the area and depth of UHPC on the failure mode and punching shear capacity are investigated. Test results indicate that the application of full-depth UHPC at the punching sh...

When carbon fiber reinforced polymer (CFRP) is used to strengthen steel structures, interfacial debonding between CFRP and steel can substantially compromise the composite action and trigger structural failure. This study investigates eddy current thermography (ECT) for nondestructive evaluation of CFRP-steel interface. Four CFRP-steel specimens wi...

The dataset was developed to predict the compressive strength, flexural strength, workability, and porosity of Ultra-high-performance concrete (UHPC). The dataset has 1,228 experimental data covering 24 mix design variables of UHPC. The input variables can be grouped into four categories: (1) Category 1: variables of the cementitious systems, (2) C...

This paper investigates flexural behavior of composite bridge decks composed of corrugated steel deck and ultra-high-performance concrete (UHPC) slab connected via modified clothoid-shaped (MCL-shaped) dowels. Six composite bridge deck specimens were fabricated and tested under different shear span lengths. A finite element model was established an...

To upcycle waste concrete through producing strain-hardening cementitious composites (SHCC) for sustainable and resilient structures, this research investigates the effect of fine recycled concrete powder on the fresh and hardened properties, optimizes the mixture design, evaluates the structural behavior, and assesses the life-cycle performance of...

This paper presents game theory-based strategies incorporated with metaheuristics to improve the computation efficiency and effectiveness in design optimization of civil engineering structures. The idea is that a structural optimization problem can be treated as a multiplayer game with optimization algorithms as the players. This study presents an...

High-performance fiber-reinforced cementitious composites (HPFRCCs) feature high mechanical strengths, crack resistance, and durability. Under excessive loading, HPFRCCs demonstrate dense microcracks that are difficult to identify using existing methods. This study presents a computer vision method for identification, quantification, and visualizat...

Inclined single-tower self-anchored suspension bridges feature a high adaptability to geological conditions but involve complicated structural behaviors during construction due to system transformation. The erection of the tower and main cable is accompanied by changes in internal loading and represents a challenge in bridge construction. This pape...

In this study, the dynamic behavior of a three-span hybrid continuous arch bridge under vehicle loading is investigated. The natural vibration characteristics of the bridge were analyzed through pulsation test. In the dynamic loading test, the vibrations of the bridge under different truck speeds and different pavement conditions were tested, and t...

This paper presents a distributed monitoring approach for detection, visualization, quantification, and warning for pipe corrosion using a single-mode telecommunication-grade fiber optic cable as a distributed sensor. The distributed sensor can be deployed on the surface of a pipe to measure corrosion along the pipe based on optical frequency domai...

Operation safety and efficiency of high-speed trains are prone to strong winds. This study proposes a wind hazard warning system to predict wind speed and provide warning for safe and efficient operation of trains, and shows the implementation to the Lanzhou-Xinjiang High-Speed Railway. The system is composed of monitoring, remote and central proce...

Ultra-high-performance concrete (UHPC) is a type of cement-based composite for new construction and/or restoration of existing structures to extend service life. UHPC features superior workability, mechanical properties, and durability compared with conventional concrete. However, some challenges limit the wider application of UHPC, such as low wor...

The Lanzhou-Xinjiang High-speed Railway runs through a region of over 500[Formula: see text]km that is amenable to frequent winds. The strong wind and rainfall pose a great threat to the safe operation of high-speed trains. To tackle the aforementioned climate challenges, this paper investigates the dynamic response of the high-speed train-track-br...

This research proposes an innovative steel–concrete joint, which utilizes front and rear bearing plates and concrete filled steel cells, for long-span railway hybrid box girder cable-stayed bridges. This study investigates the mechanical behavior of the steel–concrete joint through a model test and finite element analysis, aiming to understand the...

Current development of high-performance fiber-reinforced cementitious composites (HPFRCC) mainly relies on intensive experiments. The main purpose of this study is to develop a machine learning method for effective and efficient discovery and development of HPFRCC. Specifically, this research develops machine learning models to predict the mechanic...

Fiber optic sensors represent an innovative technology for automated measurement of cable forces which are critical in construction and operation of many civil engineering structures. This paper reviews the fiber optic sensors that have been developed and applied to measure cable forces, including fiber Bragg grating, interferometer, and fully dist...

In recent years, broad interests in ductile Engineered Cementitious Composites (ECC) have been accompanied by increasing amount of laboratory investigations of this material. Both wet and air curing have been applied in the preparation of specimens. However, the effect of curing condition on mechanical properties of ECC has yet to be elucidated. Th...

As an increasing amount of waste glass is produced every year, recycling glass in manufacturing concrete shows economic and environmental benefits. Recently, glass has been used as one of the ingredients to prepare high-performance fiber-reinforced cementitious composites (HPFRCCs), such as ultra-high-performance concrete and strain-hardening cemen...

Monitoring corrosion in reinforced concrete is critical to assess the health condition of structures at an early stage and enable effective and efficient asset management. Various novel fiber optic sensors have been developed and demonstrated many advantages in monitoring corrosion in reinforced concrete under different conditions. However, current...

Measuring distance is critical for safety and quality in construction and operation of engineering structures. This paper proposes a framework to utilize cost-effective and robust ultra-wideband radio technology for wireless sensing of distance, presents a machine learning method based on extreme gradient boosting decision tree, and incorporates er...

Measuring distance is essential for health monitoring and condition assessment of civil engineering structures. This paper reviews recent advances in remote sensing technologies for measuring distance based on electromagnetic waves. Specifically, four families of technologies are reviewed, which are the Global Navigation Satellite Systems, microwav...

Bridges are subjected to long-term deformations in addition to deformations under design loads. In high-speed railway bridges, long-term bridge deformation and potential degradation of materials may adversely impact the operation safety and riding comfort of the railway. While a high-speed railway network is being established in China, it is signif...

This study develops a method to measure crack width using a distributed fiber optic sensor. To this end, a customized specimen was designed to manipulate cracks under precise displacement control. An optical fiber was attached on the specimen and served as a distributed sensor which measured strain distributions along the fiber based on optical fre...

This paper presents a method to measure and visualize strains and cracks in high-performance fiber-reinforced concrete using distributed fiber optic sensors based on optical frequency domain reflectometry. Two beams were prepared using high-performance concrete with two types of fibers and post-tensioned with carbon-fiber-reinforced polymer (CFRP)...