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An interchange is a pivotal traffic facility that connects highways and controls access. It is necessary to study their dynamic response characteristics to analyze the operational safety of ramp bridges on interchanges. Based on the numerical simulation results of the finite element model of the Fuxing Interchange Bridge, non-destructive measurement techniques were used to conduct field dynamic load tests on the bridge, including ramp strain testing and acceleration testing. These tests aimed to study the dynamic response characteristics of the ramp bridge under moving loads. Due to the design speed limitation of the ramp bridge, the grey prediction GM(1, 1) model was used to predict the maximum dynamic deflection, maximum dynamic strain, and vibration acceleration when the vehicle speed was 60 km/h. Subsequently, finite element software was used to simulate the dynamic deflection under vehicle speeds ranging from 30 to 60 km/h. The simulated value was compared with the predicted value, and the difference between the simulated value and the predicted value was slight. This model can evaluate the operational safety performance of off-ramps at different speeds. [ABSTRACT FROM AUTHOR]

To evaluate the true load-bearing capacity and engineering reliability of a large span through a simply supported steel box arch bridge, a load test was conducted on the bridge. The example used in this test is the Jingchu Avenue Bridge located in Jingmen City, Hubei Province. Specifically, the static load test delineated six operational conditions, measuring parameters encompassing strain, hanger cable force, deflection, and potential cracks. The dynamic load test gauged the bridge's dynamic response and various indicators, including pulse tests, vehicle tests, jump tests, and barrier-free vehicle tests. The findings indicated that the maximum measured strain values during the static load test surpassed the calculated values; nonetheless, the verification factors and relative residual strains adhered to the code requirements, and no cracks were detected. The dynamic load test unveiled that the measured frequency values exceeded the theoretical ones, the damping ratios were within the normal range, and the measured impact coefficients were lower than the values stipulated in the code, all of which were in conformance with the code requirements. The data obtained from this experiment can be utilized to refine the long-term maintenance plan for the bridge, especially as it holds considerable value for structural health monitoring and aging assessment. [ABSTRACT FROM AUTHOR]

Technological procedures related to the possession of tracks are often under heavy time constraints. Therefore, the attempts to apply dynamic load tests in the process of diagnostics of implemented construction works on modernised sections of railway infrastructure are increasingly frequent. When modernising constructing traffic constructions – even if dealing with technological works not related to the possession of tracks – it is often necessary to ensure a rapid progression of individual work activities or to carry out diagnostics tests in the sections with limited access to mechanisation. This test is reasonably suitable to detect critical areas not compliant with deformation standards. The combination of dynamic load tests with the static load test in these areas could, therefore, prove to save time as well as financial expenses spent on construction works inspection diagnostics. Based on the above-mentioned reasons, the presented article is focused on the analysis of set values of the dynamic modulus of deformation, obtained through light dynamic load test LDD 100, and the static modulus of deformation obtained by employing the test procedure set out in the methodology regarding the sub-ballast layers diagnostics used for German railways (DIN 18 134) and the methodology used for the Railways of the Slovak Republic (regulation ŽSR TS4). [ABSTRACT FROM AUTHOR]

The field load test is a direct and effective method for evaluating the performance of bridge structures. However, existing bridge field static load tests are costly and inefficient; moreover, they obstruct traffic and cause unavoidable damage to the bridge structure. As an alternative the the static load test, a random model update method based on bridge dynamic load tests and the Bayesian inference is proposed in this paper. The bridge static load test results were predicted with a high accuracy. To speed up the Bayesian method to infer the posterior probability density of the updated parameters, the Gaussian process was used in place of the finite element model, and the Bayesian inference used the Markov chain Monte Carlo method based on the delayed rejection adaptive Metropolis algorithm. First, the parameters to be modified for the bridge structure analysis model were determined based on the global sensitivity analysis method. Second, a uniform design sampling method was used to establish the Gaussian process optimization model to update the random model of the bridge structure. Finally, a reinforced concrete truss arch bridge was used to verify the correctness of the static load results of the bridge predicted by the random model update method based on dynamic load testing and Bayesian inference. The research results reveal that the prediction results of the bridge static load test based on the dynamic load test and Bayesian inference method agree with the actual test results. [ABSTRACT FROM AUTHOR]

The text of this submitted paper is devoted to the experimental dynamic analysis of the newly designed footbridge across the Jizera River in Mladá Boleslav. Theoretical modal analysis has shown potential risk that some of the natural frequencies of the bridge deck will belong to the range which is typical for pacing frequencies induced by pedestrians. The resonance behaviour of this structure should be reduced by Tuned Mass Dampers (TMD), which would be tuned for separate natural frequencies of this structure. Therefore, the experimental dynamic analysis was performed on the footbridge in order to assess the effectiveness of installed TMDs. The experiment was divided into two stages, the first one was realized at the footbridge when TMDs were not yet installed, and the second one was carried out on the footbridge with installed and activated TMDs. Moreover, the authors have performed an experimental modal analysis in order to verify the aptness of the computational model and its results. [ABSTRACT FROM AUTHOR]

This paper presents an analysis of long, large-diameter bored piles' behavior under static and dynamic load tests for a megaproject located in El Alamein, on the northern shoreline of Egypt. Site investigations depict an abundance of limestone fragments and weak argillaceous limestone interlaid with gravelly, silty sands and silty, gravelly clay layers. These layers are classified as intermediate geomaterials, IGMs, and soil layers. The project consists of high-rise buildings founded on long bored piles of 1200 mm and 800 mm in diameter. Forty-four (44) static and dynamic compression load tests were performed in this study. During the pile testing, it was recognized that the pile load–settlement behavior is very conservative. Settlement did not exceed 1.6% of the pile diameter at twice the design load. This indicates that the available design manual does not provide reasonable parameters for IGM layers. The study was performed to investigate the efficiency of different approaches for determining the design load of bored piles in IGMs. These approaches are statistical, predictions from static pile load tests, numerical, and dynamic wave analysis via a case pile wave analysis program, CAPWAP, a method that calculates friction stresses along the pile shaft. The predicted ultimate capacities range from 5.5 to 10.0 times the pile design capacity. Settlement analysis indicates that the large-diameter pile behaves as a friction pile. The dynamic pile load test results were calibrated relative to the static pile load test. The dynamic load test could be used to validate the pile capacity. Settlement from the dynamic load test has been shown to be about 25% higher than that from the static load test. This can be attributed to the possible development of high pore water pressure in cohesive IGMs. The case study analysis and the parametric study indicate that AASHTO LRFD is conservative in estimating skin friction, tip, and load test resistance factors in IGMs. A new load–settlement response equation for 600 mm to 2000 mm diameter piles and new recommendations for resistance factors φ qp, φ qs, and φ load were proposed to be 0.65, 0.70, and 0.80, respectively. [ABSTRACT FROM AUTHOR]

In construction projects, conducting dynamic load tests on all piles proves impractical. Selective testing estimates bearing capacity, while the remaining piles rely on penetration depth for management. This approach, however, faces reliability issues due to varying conditions among piles. Technological advancements, such as non-contact hammers and sensors, have enhanced the accuracy of penetration depth measurements during final driving. Nonetheless, relying solely on penetration depth for construction and quality management remains problematic. This study, therefore, focuses on enhancing the use of driving formulas to improve pile quality management, particularly for the widely used pre-stressed high-strength concrete (PHC) piles. To improve pile quality management, existing driving formulas underwent review and refinement. Utilizing 258 dynamic load test data from various sites, the Hiley, Gates, and Danish formulas underwent validation through statistical analysis and graphical comparison. Enhancements to the Gates formula, achieved through curve fitting with actual data and the application of segment-based coefficients, demonstrated increased accuracy in bearing capacity estimation. These improvements offer a more reliable approach to pile quality management in construction projects. [ABSTRACT FROM AUTHOR]

The text of this submitted paper is devoted to the experimental dynamic analysis of the newly designed footbridge across the Jizera River in Mladá Boleslav. Theoretical modal analysis has shown potential risk that some of the natural frequencies of the bridge deck will belong to the range which is typical for pacing frequencies induced by pedestrians. The resonance behaviour of this structure should be reduced by Tuned Mass Dampers (TMD), which would be tuned for separate natural frequencies of this structure. Therefore, the experimental dynamic analysis was performed on the footbridge in order to assess the effectiveness of installed TMDs. The experiment was divided into two stages, the first one was realized at the footbridge when TMDs were not yet installed, and the second one was carried out on the footbridge with installed and activated TMDs. Moreover, the authors have performed an experimental modal analysis in order to verify the aptness of the computational model and its results.

In this paper, joint precast piles with a cross-section of 400 × 400 mm and a pin-joined connection were considered, and their interaction with the soil of Western Kazakhstan has been analyzed. The following methods were used: assessment of the bearing capacity using the static compression load test (SCLT by ASTM) method, interpretation of the field test data, and the dynamic loading test (DLT) method for driving precast concrete joint piles, including Pile Driving Analyzer (PDA by ASTM) and Control and Provisioning of Wireless Access Points (CAPWAP) methods. According to the results, the composite piles tested by the PDA (by ASTM) method differ by 15 percent compared to the static load method, while the difference between the dynamic DLT (by ASTM) method and the static load (by ASTM) method was only 7 percent. So, according to the results, the alternative dynamic method DLT (by ASTM) is very effective and more accurate compared to other existing methods. [ABSTRACT FROM AUTHOR]

The field load test is a direct and effective method for evaluating the performance of bridge structures. However, the existing bridge static load tests on site are costly, inefficient, and obstruct traffic; moreover, improper loading may also cause some damage to the bridge structure. This paper proposes a random model update method based on bridge dynamic load tests and the Bayesian inference as an alternative to the static load test. The Gaussian process model was used instead of the finite element model to reduce the cost of model calculation. Furthermore, choose the Markov Chain Monte Carlo (MCMC) method based on delay rejection adaptive Metropolis algorithm for Bayesian inference to improve the speed of the Bayesian method inferring the posterior probability density of updated parameters. First, the parameters to be updated for the bridge structure analysis model were determined based on the global sensitivity analysis method. Second, a uniform design sampling method was used to establish the Gaussian process optimization model to update the random model of the bridge structure. Finally, a reinforced concrete truss arch bridge was used to verify the correctness of the static load results of the bridge predicted by the random model update method based on dynamic load testing and Bayesian inference. The results show that the predicted results of the bridge static load test based on the dynamic load test and Bayesian reasoning method have an excellent agreement with the measured results, and this method can effectively overcome the adverse effects of the existing bridge static load test. [ABSTRACT FROM AUTHOR]

Cable-stayed bridges (CSBs) are flexible and complex structures. Impact-induced vibrations may play an important role in the behaviours of the structural elements. Much effort has been devoted to clarifying the experimental static and dynamic responses of CSBs. However, experimental dynamic responses of the structural elements of CSBs under impact-induced vibrations have not been widely addressed in the literature. The focus of this paper is on the real experimental dynamic behaviours of cables, decks and pylons in CSBs under impact-induced vibration due to fully loaded trucks passing over a bump positioned on the deck centre. Tests were carried out on the new Kömürhan CSB under the passage of two 40 t trucks travelling at 30 km/h and passing over a timber bump of 50 mm thickness. The dynamic responses of the structural elements were recorded using load cells and two- and three-dimensional accelerometers. Forces, accelerations and frequencies of the main- and back-span cables and the acceleration responses of the deck and pylon, recorded with and without impact effects, were evaluated and compared. Significant impact-induced amplification ratios on the responses of the main- and back-span cables, deck and pylon were observed for the studied bridge. [ABSTRACT FROM AUTHOR]

An interchange is a pivotal traffic facility that connects highways and controls access. It is necessary to study their dynamic response characteristics to analyze the operational safety of ramp bridges on interchanges. Based on the numerical simulation results of the finite element model of the Fuxing Interchange Bridge, non-destructive measurement techniques were used to conduct field dynamic load tests on the bridge, including ramp strain testing and acceleration testing. These tests aimed to study the dynamic response characteristics of the ramp bridge under moving loads. Due to the design speed limitation of the ramp bridge, the grey prediction GM(1, 1) model was used to predict the maximum dynamic deflection, maximum dynamic strain, and vibration acceleration when the vehicle speed was 60 km/h. Subsequently, finite element software was used to simulate the dynamic deflection under vehicle speeds ranging from 30 to 60 km/h. The simulated value was compared with the predicted value, and the difference between the simulated value and the predicted value was slight. This model can evaluate the operational safety performance of off-ramps at different speeds.

To evaluate the true load-bearing capacity and engineering reliability of a large span through a simply supported steel box arch bridge, a load test was conducted on the bridge. The example used in this test is the Jingchu Avenue Bridge located in Jingmen City, Hubei Province. Specifically, the static load test delineated six operational conditions, measuring parameters encompassing strain, hanger cable force, deflection, and potential cracks. The dynamic load test gauged the bridge’s dynamic response and various indicators, including pulse tests, vehicle tests, jump tests, and barrier-free vehicle tests. The findings indicated that the maximum measured strain values during the static load test surpassed the calculated values; nonetheless, the verification factors and relative residual strains adhered to the code requirements, and no cracks were detected. The dynamic load test unveiled that the measured frequency values exceeded the theoretical ones, the damping ratios were within the normal range, and the measured impact coefficients were lower than the values stipulated in the code, all of which were in conformance with the code requirements. The data obtained from this experiment can be utilized to refine the long-term maintenance plan for the bridge, especially as it holds considerable value for structural health monitoring and aging assessment.

As important load-bearing structures, suspension cables have been widely used in suspension bridges, engineering ropeways, cable suspension systems and other special equipment. Their dynamic problems have always been a research hotspot. Especially for complex cable systems such as engineering ropeways and cable lifting equipment, there will be moving loads acting on multi-span continuous friction-slip cable structures, resulting in nonlinear coupled vibration. Therefore, few scholars have studied how to calculate the nonlinear coupling vibration effect between such moving loads and multi-span continuous cables considering friction slip. Therefore, this paper proposes the use of the combination of the direct stiffness method and the Newmark-β integration method to solve the nonlinear system of equations of motion, which can be derived from the coupled vibration response between the moving load and the main cable. The corresponding calculation program is prepared. Combined with the dynamic load test and simulation results of engineering cases, the correctness and reasonableness of the coupled vibration equations and the program can be verified through comparative analysis. The results show that the calculation results of the self-programmed program are in good agreement with the dynamic load test results, in which the maximum error of the vertical displacement in the span is −4.40% and 0.86%, and the error of the static calculation reaches −13.90%. The impact effect is more obvious when hoisting the weight out of the pulling cable, in which the impact coefficient of the main cable can be up to 2.0. The impact coefficient of the deviation of the cable tower is 4.0. During the traveling process of the moving load, the vertical downward deflection of the main cable at the action point is the largest, and the upward deflection is in the region of 0.2~0.8L from the action point. [ABSTRACT FROM AUTHOR]

The large-span prestressed concrete beam bridge has been widely used due to its advantages of high structural stiffness, smooth and comfortable traffic, good seismic performance, and mature construction technology. However, after a long period of service, such bridges may develop cracks in their structure due to the long-term effects of natural environment and overloading, which can affect their safe carrying capacity. This problem is particularly prominent for long-span bridges over the sea. Therefore, in order to accurately assess the actual working condition and carrying capacity of an in- service long-span prestressed concrete beam bridge over the sea, on-site static and dynamic load tests on a bridge that has been in service for 15 years are conducted. The characteristics such as vibration mode were analyzed using finite element analysis. The research results indicate that the structural performance of the bridge remains good, but the actual carrying capacity has decreased due to structural damage and crack formation caused by the environmental conditions in the marine area and long-term service. The findings of this study can provide reference for the maintenance and strengthening of similar in-service bridges. [ABSTRACT FROM AUTHOR]

In construction projects, conducting dynamic load tests on all piles proves impractical. Selective testing estimates bearing capacity, while the remaining piles rely on penetration depth for management. This approach, however, faces reliability issues due to varying conditions among piles. Technological advancements, such as non-contact hammers and sensors, have enhanced the accuracy of penetration depth measurements during final driving. Nonetheless, relying solely on penetration depth for construction and quality management remains problematic. This study, therefore, focuses on enhancing the use of driving formulas to improve pile quality management, particularly for the widely used pre-stressed high-strength concrete (PHC) piles. To improve pile quality management, existing driving formulas underwent review and refinement. Utilizing 258 dynamic load test data from various sites, the Hiley, Gates, and Danish formulas underwent validation through statistical analysis and graphical comparison. Enhancements to the Gates formula, achieved through curve fitting with actual data and the application of segment-based coefficients, demonstrated increased accuracy in bearing capacity estimation. These improvements offer a more reliable approach to pile quality management in construction projects.

In this paper, joint precast piles with a cross-section of 400 × 400 mm and a pin-joined connection were considered, and their interaction with the soil of Western Kazakhstan has been analyzed. The following methods were used: assessment of the bearing capacity using the static compression load test (SCLT by ASTM) method, interpretation of the field test data, and the dynamic loading test (DLT) method for driving precast concrete joint piles, including Pile Driving Analyzer (PDA by ASTM) and Control and Provisioning of Wireless Access Points (CAPWAP) methods. According to the results, the composite piles tested by the PDA (by ASTM) method differ by 15 percent compared to the static load method, while the difference between the dynamic DLT (by ASTM) method and the static load (by ASTM) method was only 7 percent. So, according to the results, the alternative dynamic method DLT (by ASTM) is very effective and more accurate compared to other existing methods.

Faced with the structural performance evaluation of a large number of bridges, bridge management and maintenance departments have urgently sought a quick method for evaluating bridge performance. The load test is currently a direct and effective method for assessing the conditions of bridge structures. However, this method is costly, time-consuming, inefficient, requires closed traffic, and can cause damage to the structure itself. In response to this problem, this paper proposes a new low-cost method combined with the Kriging proxy model for fast and accurate prediction of bridge static behavior based on fast bridge dynamic load test data. To verify the correctness and feasibility of the method in this study, a three-span continuous reinforced concrete oblique-leg rigid frame bridge is considered as the engineering application test object. The research results reveal that the finite element model of the bridge can be updated based on the dynamic load test data of the bridge combined with the Kriging proxy model, and the static load test results can be accurately predicted. And the predicted results are consistent with the measured results in the field. The method proposed in this study is not associated with the negative impacts of the bridge static load test and uses more efficient, fast, and accurate means to comprehensively analyze and predict the static behavior of a large number of existing bridges. It could inform approaches for rapid evaluation of the structural performance of existing bridges and the decision-making of reinforcement and maintenance. [ABSTRACT FROM AUTHOR]

This paper presents the development of a novel model for predicting setup of closed-ended steel pipe (CEP) piles driven in predominantly fine-grained soils using gene expression programming (GEP). The proposed GEP model incorporates both pile and soil properties and is based on dynamic pile load test data obtained from 109 piles installed at 59 different sites. Multiple variable regression analyses conducted on the compiled dataset showed that the most influential parameters in predicting the time-dependent resistance of driven piles were the resistance mobilized at the end of pile installation, time elapsed after installation, pile shaft surface area, and average silt content along the pile length. The data were divided into a training set for model calibration and a validation set for model verification. Sensitivity analysis was performed to assess the model's robustness. A comparison of the new GEP model with existing pile setup models in the literature was carried out using the collected data, which demonstrated that the proposed GEP model significantly outperformed the tested models. Additionally, data from 22 additional CEP piles were compiled from the literature for model verification purposes. The results showed that the proposed GEP model can predict the total pile resistance with good accuracy. [ABSTRACT FROM AUTHOR]

As important load-bearing structures, suspension cables have been widely used in suspension bridges, engineering ropeways, cable suspension systems and other special equipment. Their dynamic problems have always been a research hotspot. Especially for complex cable systems such as engineering ropeways and cable lifting equipment, there will be moving loads acting on multi-span continuous friction-slip cable structures, resulting in nonlinear coupled vibration. Therefore, few scholars have studied how to calculate the nonlinear coupling vibration effect between such moving loads and multi-span continuous cables considering friction slip. Therefore, this paper proposes the use of the combination of the direct stiffness method and the Newmark-β integration method to solve the nonlinear system of equations of motion, which can be derived from the coupled vibration response between the moving load and the main cable. The corresponding calculation program is prepared. Combined with the dynamic load test and simulation results of engineering cases, the correctness and reasonableness of the coupled vibration equations and the program can be verified through comparative analysis. The results show that the calculation results of the self-programmed program are in good agreement with the dynamic load test results, in which the maximum error of the vertical displacement in the span is −4.40% and 0.86%, and the error of the static calculation reaches −13.90%. The impact effect is more obvious when hoisting the weight out of the pulling cable, in which the impact coefficient of the main cable can be up to 2.0. The impact coefficient of the deviation of the cable tower is 4.0. During the traveling process of the moving load, the vertical downward deflection of the main cable at the action point is the largest, and the upward deflection is in the region of 0.2~0.8L from the action point.

Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper application of a method developed in Brazil for predicting driving transferred energy. The method was recently developed in Brazil and was used in short piles in 2019. In this more recent paper, it was sought to extend the application of the method to long piles (Pile length > 30 m) in soils of different characteristics. It is based on the pile measurements of permanent and elastic displacements during driving and calibration of the site-specific λ coefficient. The article validates the methodology in a case study of two sites with 159 dynamic tests of steel-driven piles in the cities of Santos (SP) and Itaguaí (RJ). Through calibration of λ, the energy predictions showed a good correlation to those obtained from the dynamic tests. There is an additional contribution to the original author's analysis – increasing the previous testing database – about the correlation between λ and the pile length, as the study includes piles from 36 to 60 m in length – a range that was not included during the author's first method evaluation. Its major advantage is allowing effective energy estimations in non‑instrumented piles as it is not practical to monitor every single pile of a construction driving site to assess the transferred energy. The presented method is useful in the practice of driven foundation and its quality control. [ABSTRACT FROM AUTHOR]

Prior to casting of concrete, proper supervision and attention to camber provision in bridge construction are required. It is also critical to use an appropriate quality control manual, pay due attention to reinforcement bar placement, and have a high level of formwork design before construction begins. If these issues are not properly addressed, performance of structures will be affected. In this research, performance of a 40.5m box-girder reinforced concrete bridge which was constructed without having proper camber is studied. As camber was the most important issue of the bridge under investigation, the impact on strength and serviceability requirements is compared to the standard. A dynamic load test with an Arduino type accelerometer is performed to assess the bridge's current condition in relation to the serviceability limit requirement. The deterioration of reinforced concrete (RC) sections due to reinforcement corrosion, creep, and an increase in load intensity, as well as the corresponding statistical distributions are considered to estimate the long-term effect of bridge deflection. Timevariant analysis results showed a linear decrease in deflection reliability indices with the bridge's expected service life of 58 years. After strengthening with steel plates, its service period increased to 85 years. [ABSTRACT FROM AUTHOR]

In this paper, the construction process of a cable-stayed bridge with corrugated steel webs was monitored. Moreover, the end performance of the bridge was verified by load test. Owing to the consideration of the bridge structure safety, it is necessary to monitor the main girder deflection, stress, construction error and safety state during construction. Furthermore, to verify whether the bridge can meet the design requirements, the static and dynamic load tests are carried out after the completion of the bridge. The results of construction monitoring show that the stress state of the structure during construction is basically consistent with the theoretical calculation and design requirements, and both meet the design and specification requirements. The final measured stress state of the structure is within the allowable range of the cable-stayed bridge, and the stress state of the structure is normal and meets the specification requirements. The results of load tests show that the measured deflection values of the mid-span section of the main girder are less than the theoretical calculation values. The maximum deflection of the girder is −20.90 mm, which is less than −22.00 mm of the theoretical value, indicating that the girder has sufficient structural stiffness. The maximum impact coefficient under dynamic load test is 1.08, which is greater than 1.05 of theoretical value, indicating that the impact effect of heavy-duty truck on this type of bridge is larger. This study can provide important reference value for construction and maintenance of similar corrugated steel web cable-stayed bridges. [ABSTRACT FROM AUTHOR]

In fuel cells, chemical energy is directly converted into heat and electricity without any emissions which makes them an attractive substitute for various energy needs. Fuel cells have high energy conversion ratio and high-power densities which make them suitable for automotive applications. However, these fuel cell systems suffer with low reliability and durability as system components develop faults during operation resulting in degradation and diminished system performance. In this context, fault detection and fault mitigation strategies are being extensively developed. Diagnostic approaches like electrochemical impedance spectroscopy, cyclic voltammetry, and galvanostatic analysis offer a truthful representation of the State of Health (SOH) of the fuel cell. However, these approaches are intrusive and require pausing the operation of the fuel cell effecting its integrity. Machine learning based fault detection and SOH estimation is a non-intrusive approach where a mapping function is established between the indicators and SOH. The SOH of a fuel cell can be correlated to the patterns in sensor signals or indicators. Indicators that influence SOH are cell voltages, current density distribution, impedance spectra, acoustic emission and magnetic fields. Developing an accurate fault detection and state estimation technique through data driven machine learning approaches will allow corrective measures to avoid irreversible faults and improve the reliability and durability of fuel cells.

Xinhe Bridge is a newly built large-span half-through steel box basket-handle arch bridge with a main span of 196 m. In order to evaluate the mechanical performance of the bridge under the service load and verify whether it reaches the design expectations, load tests have been carried out on the bridge. In the static load test, 11 control sections were selected for measuring several mechanics parameters, including strain, suspender cable force, deflection, and horizontal displacement of the abutment. In the dynamic load test, the natural frequency and the dynamic response under the vibration excitation, such as a vehicle running load, bumping load, and braking load, were tested. The results show as follows. The structural verification coefficient and relative residual meet the requirements of the code. The cable force of the suspender and the horizontal displacement of the abutment have a large surplus. The measured natural frequency is higher than the calculated frequency. The measured damping ratio is less than 5%. The measured impact amplification coefficient is 1. 176 ~ 1. 371. Each performance of the test achieves the design expectation. [ABSTRACT FROM AUTHOR]

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Based on the Yongjiang Bridge, this paper used the numerical calculation and the field dynamic load test to study the coupled vibration and dynamic response of the steel box hybrid girder cable-stayed railway bridge. Each vehicle in the train was simulated with 31 degrees of freedom, and the oscillatory differential equation of vehicle-bridge coupling was established by MATLAB software. Afterwards, the field tests were also conducted to determine the free vibration characteristics as well as the strain, displacement, and acceleration of the bridge superstructure under trains moving at different speeds and braking at a specified position from a set speed. According to the dynamic load test and Vehicle-Bridge Coupling Vibration analysis, the following conclusions are obtained: (1) The calculated results of vehicle-bridge coupling vibration agreed well with the measured ones, and the program could be used to analyze the dynamic performance of Railway cable-stayed bridges with steel box composite girders. (2) The measured first-order natural frequencies of transverse, vertical and longitudinal vibration were 0,39 Hz; 0,49 Hz and 0,88 Hz, respectively. The dynamic coefficients are 1,04 – 1,13, the maximum lateral and vertical accelerations are 1,10 m/s2 and 1,11 m/s2, and the maximum derailment coefficient and load reduction rate are 0,55 and 0,39, respectively. These data showed that the dynamic parameters of bridges and vehicles met the requirements and had good stiffness and dynamic performance. (3) This paper, using the frequency limit of simply supported beam to restrain the natural frequencies of cable-stayed bridges is not appropriate, and it is necessary to propose the natural frequency limit value of cable-stayed bridge.

Copyright of Revista Mackenzie de Engenharia e Computação is the property of Universidade Presbiteriana Mackenzie, Revista Mackenzie de Engenharia e Computacao and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Architecture & Civil Engineering is the property of Chang'an Daxue Zazhishe and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Piles driven in cohesive soils usually experience a large increase in capacity over time, known as setup or freeze. This paper presents the field results of two test piles that were driven in two different locations of Louisiana to evaluate the pile setup behavior. Laboratory and in situ soil testings (cone penetration test, CPT) were conducted to characterize the subsurface soil properties. Several dynamic load tests (DLTs) and one static load test (SLT) were conducted on each test pile at different times after end of driving (EOD) to quantify the magnitude and rate of setup. The test pile in one site was instrumented with vibrating wire strain gages to calculate the load-distribution along the length of the pile during the static load test. With the aid of Case Pile Wave Analysis Program (CAPWAP®) analyses and load distribution plots from strain gages, skin friction and end-bearing capacities were measured separately. The load test results showed that the setup was mainly attributed to increase in skin friction with time and end-bearing capacity remained almost constant. The load test results also showed that setup behavior was more significant in soft cohesive soil. The pile capacity of one test pile was also evaluated using different CPT methods (such as Schmertmann, De Ruiter and Beringen, LCPC). The result showed that all the methods can estimate the pile capacity with good accuracy. [ABSTRACT FROM AUTHOR]

Considering a great number of newly built bridges at home and abroad, this paper aims to study how to effectively check the technical status such as construction quality, and bearing capacity etc. of the prestressed concrete simply supported bridges using the dynamic and static load tests. First, the finite element calculation was conducted to simulate various construction conditions of the bridge and calculate the actual bridge's bearing capacity. Then, taking Yanxi Bridge as an example, the authors carried out dynamic and static load tests and finite element theoretical calculations to analyze the deflection and strain of the bridge structure during the static load test, as well as the frequency, damping and patterns obtained from the dynamic load test. As a result, the bridge quality was reasonably evaluated. The analysis results show that the bearing capacity and structural rigidity of the bridge meet the design requirements. The research findings shall provide references for the completion acceptance of other bridges. [ABSTRACT FROM AUTHOR]

• Field-measured bridge DLFs under random traffic excitations decrease with increasing load levels. • Specification-level bridge DLF extrapolated using deflection-measured DLFs at low load levels. • Two extrapolation methods proposed using linear regression and bivariate extreme value modeling. • Numerical traffic-bridge coupled analysis and field load tests validate extrapolation methods. • Methodology showcased with field-measured deflections on a long-span continuous girder bridge. Field-measured dynamic load factors (DLFs) are underutilized for bridge health assessment. Bridge practitioners often face confusion when comparing field-measured DLFs to specification design values owing to significant DLF variations across different traffic load levels. However, mathematical relations or methods correlating bridge DLFs and load levels are lacking. To address this challenge, this study proposes practical methods for determining specification-level DLFs using field-deflection measurements during ambient traffic excitations. Deflections from a continuous rigid-frame bridge over six months were measured, and DLFs were computed using hourly maximal total deflections and their corresponding static deflections. Two approaches were developed and validated to extrapolate the specification-level DLF using field-measured DLFs of low load levels. Extrapolated DLFs from both methods illustrated a noticeable downward trend in DLFs relative to load levels. Both methods yielded consistent results, falling within the range of 0.03–0.09, equivalent to the design DLF value of 0.05 for the bridge under study. No significant temporal-dependent changes in extrapolated DLFs were evident, indicating that bridge performance and pavement roughness met design expectations and did not deteriorate significantly. This study provides an alternative data-driven approach that utilizes field-measured DLFs to assess the health condition of bridges. [ABSTRACT FROM AUTHOR]

The static axial pile bearing capacity depends mainly on the developed pile–soil interaction. Hence, to determine a realistic and reliable ultimate pile bearing capacity, the pile–soil interaction needs to be identified and described precisely. One relevant field for this application is dynamic load tests (DLTs). During a DLT, the pile bearing capacity is deduced from measurements at the pile head. Current procedures of deriving the bearing capacity of open-ended piles from these measurements are lagging behind regarding the description of the pile–soil interaction for open-ended piles and the influence of the pore fluid response. Hence, a new technique based on the finite element method is developed, which captures the key aspects for DLT results correctly and is capable of deriving the static pile bearing capacity. The method is validated against dynamic and static load test data obtained from centrifuge tests on large diameter monopiles. An application to field test data of tubular steel piles is shown. The developed approach seems suitable to assess the static pile bearing capacity based on DLT measurements. [ABSTRACT FROM AUTHOR]

In order to evaluate the actual bearing capacity and condition of a cable-stayed bridge in detail, the static and dynamic load tests of the bridge are carried out to test and analyze the static parameters such as the strain of the main girder control section, the local strain of the bridge deck, the deflection of the main girder, the vertical deviation of the tower top and the strain of the tower root, and the dynamic response of the bridge, such as impact coefficient, natural frequency and mode of vibration. The analysis results show that the measured data of each measuring point are generally in good agreement with the calculation. The check coefficient of some measuring points is greater than 1. 0, and the impact coefficient is greater than the calculated value in the dynamic load test. The damping ratio is 0. 338%-1. 115%, which indicates that the bearing capacity of the structure is low. The research conclusion has certain significance for the analysis of the bearing capacity of similar bridges. [ABSTRACT FROM AUTHOR]

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This paper presents a new approach of estimating pile setup starts from the end-of-drive (EOD) resistance by the use of a power function model followed by a log-linear function. Often pile setup is estimated using the Skov and Denver(in: Proceedings of the 3rd international conference on the application of stress-wave theory to piles, Canada, 1988) model, which requires knowing the pile resistance at a reference time (to). This requires additional effort for testing the pile at the reference time (to). This effort may cause delay in the foundation construction and thus increasing the cost of construction. Pile load testing program was conducted on seven 914 (36 in.) square close-ended prestressed concrete (PSC) test piles at the Caminada Bay bridge project in coastal Louisiana to develop a methodology to estimate pile setup effectively starting from EOD resistance. Several dynamic load tests (DLTs) were performed on each test pile, with waiting periods of 60 min to 55 days after installation, to measure the magnitude and rate of setup. Static load tests (SLTs) were also performed at the end of the load testing program to validate the results of dynamic load tests. The load testing results showed that the total resistance increased up to 12 times of the EOD resistances after 28 days from EOD. The Skov and Denver (1988) setup parameter “A” was calculated for each test pile using different initial reference times (to). The results showed that the setup parameter “A” was highly variable and uncertain for to less than 1 day. This paper proposes a new power pile setup model that can be used to estimate pile setup immediately after EOD to the initial reference time, to, which is usually 1 day for a log-linear model. The proposed model was validated using results from published case studies for various geological conditions, which shows that the results of the model effectively match the setup test results within a small tolerance. [ABSTRACT FROM AUTHOR]

Structural assessment of masonry bridges is of great importance due to long service-life and deterioration of masonry and a growing demand for increasing the axle load. An important factor in doing so is the dynamic amplification factor (DAF), which accounts for dynamic impact of moving trains on a bridge. Accurate evaluation of DAF leads to sustainable management of existing bridges. A total of 845 dynamic load tests are carried out on 11 masonry arch bridges in Iranian railway network and results are used to assess the effect of train formation, train speed, span length, rise/span ratio, first natural frequencies in vertical and lateral directions, and combined modulus of elasticity of masonry and mortar on DAF. The correlation coefficients between first vertical frequency and modulus of elasticity and DAF are 0.53 and 0.56, respectively, which are the highest amongst studied parameters. Moreover, root mean square deviation between experimental DAF values and those determined according to various standards are determined and compared. [ABSTRACT FROM AUTHOR]

The present paper analyzes the accuracy of the load capacity prediction using the semi-empirical methods Aoki and Velloso (1975), Decourt (1996) and Brasfond (1991), seeking a better approximation to the results obtained in loco through dynamic load test in stakes of the root type realized in an infrastructure work. The objective is to present a methodology that advances the quality of predicted behavior of injected cuttings, demonstrating the efficiency of the proposed methods through statistical analysis and linear correlations, evaluating the semi-empirical method that best approximates the results obtained in loco. Observing that the injection factor with air blow application is decisive with respect to the increase of the section of the stake and load capacity, due to the physical indexes of the adjacent soil. It was verified that the method of Decourt (1996) is the one closest to the load of rupture obtained through six tests of dynamic load, proving the effectiveness of the method through the prediction of load associated with the statistical analyzes. [ABSTRACT FROM AUTHOR]

Estimation of bearing capacity and settlement plays an essential role in designing pile foundations of buildings. This paper presents the results of pile static and dynamic loading tests taken place in the construction sites of Caspian Sea Port Prorva and Tengiz. The static loading tests (SLT) and static compression loading tests (SCLT) were carried out according to the Kazakhstan GOST and ASTM standards correspondingly. The dynamic loading tests (DLT) were performed by GOST, as well as by pile dynamic analyzer (PDA) in accordance with ASTM standards. According to the results of DLT of driven joint piles (with a cross-section of 40×40 cm, lengths of 25 m and 27 m) performed by PDA, the bearing capacity of the piles was 2143 kN. In the construction site of Prorva, the bearing capacities of driven joint piles according to the results of SCLT were 2067 kN and 2042 kN. In the construction site of Tengiz, the bearing capacities of driven piles tested by SLT were 1000 kN and 1605kN. These investigations are important for the understanding of soil-structure interaction, especially of driven piles with a cross-section of 40x40 cm and lengths of 12 and 16m in construction site Tengiz. [ABSTRACT FROM AUTHOR]

The typical properties of Lightweight Concrete Pile (LCP) are low density, low strength and high porosity. Such inherent properties made use of LCP for deep foundation are still rare. In spite of Normal Concrete Pile (NCP) has been widely used in civil engineering industry, the use of LCP such as palm oil clinker concrete pile (p-LCP) and foamed concrete pile (f-LCP) for floating foundation must be verified. The purpose of this study was to perform the static and dynamic load tests for assessing the performance of p-LCP and f-LCP and that of NCP as reference. The physical characteristics of either p-LCP or f-LCP have higher average values of compressive stress and driving resistance comparing with NCP. Features of good performance for p-LCP and f-LCP can be used for deep foundation of particular structures in soft soil and were verified to contribute to material and structural perspectives for the future of geotechnical engineering. [ABSTRACT FROM AUTHOR]